CA1187281A - High turbulence heat transfer oven - Google Patents
High turbulence heat transfer ovenInfo
- Publication number
- CA1187281A CA1187281A CA000444252A CA444252A CA1187281A CA 1187281 A CA1187281 A CA 1187281A CA 000444252 A CA000444252 A CA 000444252A CA 444252 A CA444252 A CA 444252A CA 1187281 A CA1187281 A CA 1187281A
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- Prior art keywords
- air
- fan
- objects
- housing
- oven
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
HIGH TURBULENCE HEAT TRANSFER OVEN
ABSTRACT OF THE DISCLOSURE
Disclosed is a high turbulence heat transfer oven for drying objects, including a housing having a continuous common essentially open interior through which objects to be dried are passed along an open path of travel and fan means disposed at spaced intervals along the path and in the common open interior of the housing for cooperating in producing a circulation of air in the interior from the front side of each of the fan means toward the objects and thence around to the back sides of the fan means. Each fan means directs air against the objects and spaced heating means along the path of travel provide for heating only a portion of the air as it is returned to the back sides of each of the fan means for inter-mixing with the air in the essentially open interior. Control means may be provided for individually t respectively controlling the amount of heat delivered by the heating means. Alternatively, control means may be provided for individually, respectively controlling the speed of the fan means.
ABSTRACT OF THE DISCLOSURE
Disclosed is a high turbulence heat transfer oven for drying objects, including a housing having a continuous common essentially open interior through which objects to be dried are passed along an open path of travel and fan means disposed at spaced intervals along the path and in the common open interior of the housing for cooperating in producing a circulation of air in the interior from the front side of each of the fan means toward the objects and thence around to the back sides of the fan means. Each fan means directs air against the objects and spaced heating means along the path of travel provide for heating only a portion of the air as it is returned to the back sides of each of the fan means for inter-mixing with the air in the essentially open interior. Control means may be provided for individually t respectively controlling the amount of heat delivered by the heating means. Alternatively, control means may be provided for individually, respectively controlling the speed of the fan means.
Description
~L~1372~
EIIGH TURB~LENCE HF~T TQ~ISE'ER 0~1E~I
BACKGROI~lD OF T~E I~VENTIOM
This application is a division of Canadian Serial ~o.
418,716, filed December 29, 1982 which is a division o~
Canadian Serial No. 337,590, filed October 15, 1979.
1 Field of the Invention .
This invention relates to an apparatus and process for heating and drying objects and is more particularly concern-ed with a forced convection heat transfer oven through which objects are passed Eor drying and in which heated air is circulated.
EIIGH TURB~LENCE HF~T TQ~ISE'ER 0~1E~I
BACKGROI~lD OF T~E I~VENTIOM
This application is a division of Canadian Serial ~o.
418,716, filed December 29, 1982 which is a division o~
Canadian Serial No. 337,590, filed October 15, 1979.
1 Field of the Invention .
This invention relates to an apparatus and process for heating and drying objects and is more particularly concern-ed with a forced convection heat transfer oven through which objects are passed Eor drying and in which heated air is circulated.
2 Description of the Prior Art .
In the past ovens have been used to dry paint and other coatings on appliances, furniture and automobile bodies and other objects and articles of manuacture. In some instances electric and gas Eired infra red heaters have been used Eor the heat source in these ovens. ~ther ovens have used air as the heat transfer medium with little or no turbulence generated around the object to be heated (free convection oven). other ~0 ovens have employed turbulent air or air that is discharged at relatively high velocity. In previous applications where turbulent air was used it has been necessary to develop static pressures by the use of centrifugal fans in order to develop the relative high discharge velocity required. This method of generating turbulence requires large horse power.
Exhaust fans are also quite common where painting is being done to remove the fumes of the paint and the air which carries the paint.
21~1 SUMMARY OF THE I~;lV~:~lTION
In one aspect the lnven-tion ~ertains to a hiqh turbulence heat transfer oven Eor drying objects, includin~ a housing having a continuous common essentially open interior throuah which objects to be dried are passed along an open path of travel and fan means disposed at spaced intervals along the path and in the common open interior of the housing for cooperating in producing a circulation of air in the interior from the front side of each of the fan means toward the objects and thence arouncl to the back sides o~ the fan means. Each ~an means directs air against the objects and spaced heating means along the path of travel provide for heating only a portion of the air as it is returned to the back sides of each of the fan means for inter-mixing with the air in the essentially open interior. Control means may be provided for individuall~, respectively controlling the amount of heat delivered by the heating means. Al~ernatively, control means may be provided for individuall~, respectively controlling the speed of the fan means.
Another aspect of the invention pertains to an oven :Eor drying objects d~spnsed therein and haviny heating means, ~herein the housing having a wall deines an interior through which objects to be dried pass. A fan assen~ly is carried by the wall, the an asse~bl~ including a hollow tubular sleeve protruding through and supported by the wall. A motor is in one end of the sleeve and the sleeve is open for the passage of air through the motor, the motor having a shaft protrudirlg from the sleeve, with a fan on the end of the shaft and within the housing.
~0 rlore particularly, disclosed is an oven having walls through which shafts, supported by fixed sleeves, project.
~37~
Radially extending propel]er blades are pro~ided on the ends of the shafts. The blades are spaced from the ~,/alls and direct air toward the surface which is to be dr:ied. In one embodiment, heat exchangers, which carry steam, are disposed on ahout the same Plane as the blades so as to heat the air passing to the back slde of the blades. Another embodiment shows the fans in staggered relationship. Sti]l another embodiment shows the fans operation in alternate directions and heaters between the fans so that the exhaust of one fan delivers air through the heater to the next fan.
Other embodiments teach gas fired heaters discharging to the back side of the fans and fixed within a duct for heating air delivered to the fans.
In operation, the apparatus of the pxesent invention moves Iarge volumes of air over th~ surfaces to be dried with no appreciable back pressure and with great efficiency in the use of power. The surfaces to be dried are thus heated ~uite rapidl~. Since the air is not blown toward an entrance or exit opening through which the object passes, and air is exhausted from wi~hin the oven, there are no appreciable losses of heat to the interior of a fac-tor~ and no appreciable contamination of air in the factory. Thus, no ap~reciable sealing of the oven is necessary.
The oven can be quite readil~ and easil~ zoned bath as to zones o~ diEerent temperature and ~ones of different air velocity. The cost o~ producing and operating the ovan is qui~e nominal since small motors are used as opposed to the large motors used ~ centrifugal blowers.
Other aspects, Eeatures and advantages ~f the present inven-tion will ~ecome apparent from the ollowing description when taken in conjunction with the accom~an~ing drawings where like characters of reference designate corresponding ~arts thxoughout the several views.
~7~
BRIEF DESCRIPTION OF THE DRAWING
Fig. lA is a side elevational vie~" of a portiorl of a form of oven for drying the surfaces of objec-ts, the oven being constructed in accordance with the present invention;
~ ig. ls is a side elevational view of the remainder of the oven shown in Fig. lA;
Fig. 2A is a top plan view of that portion of the oven shown in Fig. lA;
Fig. 2B is a top plan view of that portion of the oven shown in Fig. lA;
Fig. 3 i5 an end view of the front end of the oven shown in Figs. lA, lB, 2A and 2B;
Fig. 4 is an exploded perspective view of one of tne fan assemblies o~ the oven shown in Figs. lAr lB, 2Ar 2B and 3;
Fig. 5 is an end elevational view of another form of the oven of the present invention;
Fig. 6 is a fragmentary top plan view of the oven shown in Fig. 5;
Fig. 7 is an end elevational ~iew of still another form of oven of the present invention;
Fig. 8 is a fragmentary side elevational view of the oven shown in Fig. 7;
Fig. 9 is a top plan view o the oven shown in Fi~s.
7 and ~;
Fig. 10 is an end elevatlonal ~iew o another form o oven of the prasent invention;
Fig. 11 is a fragmentary side elevational view of the oven sho~ in Fig. 10;
Fig. 12 is a fragmentary side elevational view of still another oven of the present invention;
Fig. 13 is an end view of one end of the oven shown in Fi~. 12;
~37Z~:~
DESCRIPTION OF THE PREFERRED EMsoDIMENTs -Referring now in detail to the embodiments chosen for the purpose of illustrating the present invention, numeral 20, in Figs. lA, lB, 2A, 2B and 3, denote generally an inverted U shaped or channel shaped, oven housing or casing. The housing 20 includes abutting side panels 24 secured side to side to form opposed, parallel side walls 21 while abutting top panels 25, secured together in side to side fashion form the top wall 22 o the oven. Each o panels 24 and 25 includes appropriate sheets of insulation ~7 disposed within the interior o the panel and innar and outer metal sheets 27a and 27b sandwiching the insulation sheets 27.
At the ront end of the housing 20 there is an entxallce vestibule, denoted generally by numeral 30. This entrance vestibule 30 is also an inverted U-shaped or channel shaped member but is o gn~llerdimensions than the housing 20. The vestibule 30 thus has abutting opposed parallel, rectanguiar, upright, side panels 31 resting by thèir lower edges on the floor and top panels 32 joining the upper edges of the side panèls 31 to orm a roo.
3L~L8~
The housing 20 is provided ~ith a front ~aneL or wall 26 closing the front of housing 20, excep~ ~or an access opening defined by inner edges of the panel 26. The inner edges of the vestibule 30 are connected to the inner edges of the panel 26 while the outer end of the vestibule 30 is open to provide a passageway through the vestibule 30 and into the larger housing 20.
The housing 20 also has a back panel or wall 28 which has an exit opening of the same dimensions as the access opening of panel 26. Thus, an unobstructed passageway 35 is provided through which successive objects 100, carried on a conveyor 85, are fed or drying by the oven.
According to the present invention, drying is accom-plished by heated high velocity air driven by a plurality of fan assemblies 40 spaced successively along the pathway or passageway 35.
As best seen in Fig. 4, each ~an assembly 40 includes a hollo~ rectangular or square tubular casing or slee~e 41, open at both ends.~ Secured within the inner end of the casing 41 ~ is an inner or lower bearing 42 which journals a central drive shaft 43. Secured within the outer end of the casing 41 is an outer bearing alignèd with inner bearing 42 and also receiving shat 43. This outer bearing, as illustrated, i~ a thrust bearing, includes opposed bearing sections 44a and 44b. The lower or inner bearing 4~ journals the shaft 43 for both rota-tional movement and axial movement whereby the shat 43 may expand and contract with heat changes.
372~
The shaft 43 extends inwardl~ beyond beariny 42 and its inner end is provided with a bladed air propeller, fan or impeller 45. The propeller 45 includes a central hub formed of a collar 46 secured to the end of the shaft 43 and a square hub plate 47. In the present èmbodiment four flat paddle li~e blades 48 radiate from the hub 47, each blade 48 being disposed at an angle to the shaft 43 to drive the air inwardly when shaft 43 is rotated in a counterclockwise direction as viewed in Fig. 4.
For cooling the shaft 43 and bearing 42, a pair of holes 49a and 49b are provided in the casing 41 respectively adjacent the bearing formed by segments 44a, 44b and bearing 42. The suction or aspirating effect created at its back side by fan 45 induces a flow of air as indicated by the arrows 50 in Fig. 4.
The sleeve or casinq 41 projects through an appropriate hole in panel 25 and ls secured b~ an intermediate portion to one of the panels 25. For this purpose, the casing 41 has a central perime~ral flange 51 which abuts the outer surface of panel 25. T~o opposed, angle iron, brackets or straps 52, passing on opposite sides o~ the casing 41 and respectively over opposite port~ons of flange 51, extend over the surface of panel 25 and are secured by riVets or bolts 53, thereto.
Thus, the casing 41 is disposed in a fixed position extending perpendicularly through the roof panel 25 and the hole 49a is disposed externally of the housing 20.
7~
The outer end of the shaft 43 is provided ,lith a puLle-~
or sheave 55 clriven by belts 56 from a pulle~ or sheave 57 on the shaft 54 of an electric motor 58. A motor mountiny bracket 59, secured to an outer suLface of casing 41, extends Late~all~
from the casing 41 and is provided, at its outer end po~tion, with a motor mounting plate 60. Bolts (not shown) mount motor 58 on plate 60 so as to dispose its shaft 54 parallel to and spaced from shat 43. Thus, motor 58 is spaced away from and outwardly of panel 25. Also, the fan 45 is spaced an appreciable distance inward from the inner sheet 27b of panel 25.
In the present embodiment, three longitudinally spaced fan assemblies 40 are provided for housing 20~ the sha~ts 43 thereof being disposed along a lonqitudinal center line of the roof or top 22, as seen in Figs. 2A and 2B. The central fan assembly 40 is midway o housing 20 and the axes of the front and back fan assemblies 40 are equidistant from the axis o the central fan assembly 40 preferably being respectively about half the distance from the axis of the central asse~bly 40 to the ront and back panel 26 or 28, as the case may be.
The shats 43 of assemblies 40 are, thus, disposed vertically parallel to each other and are equally spaced longitudinally along the pathway o the objects 100~ Each o ~he shafts 43 disposes its fan or propeller 45 in a common hori~ontal plane, parallel ~o roo wall 22, and generally coincides with the plane o~ tha roo panels 32, as shown in Fig. 3. The diameter o each an or propeller 45 is about one-ourth to about three-ourths the width o the housing 20 ~rom side wall 21 ~o side wall 21. Preferably the diameter is about one-hal such distance.
Within the housing 20 and outboard on opposite sides of the fans or propellers 45 o~ the three assemblies 40 are a pair of parallel, longitudinally extending, heat exchangers 65a, 65b. These heat exchangers 65a and 65b are in staggered longitudinally overlapping relationship and each is a right prism or rectangular box-like member containing steam coils over which the air circulates.
As seen best in Figs. 2A and 2B ~he heat exchanger 65b extends along the right side of the front fan 45 and middle lQ or central fan 45. The heat exchanger 65a is disposed along the leEt side of the middle or central fan 45 and the rear fan 45. Thus, air circulated by the front fan 45 will pass essentially through only the hea~ exchanger 65b, the air circu-lated b~ the central fan 45 will circulate through both heat exchangers 65a and 65b, and the air Girculated by the rear Ean 45 will pass essentially through only the rear heat e~changer 65a.
Steam ls supplied to both heat exchangers 65a and 65b ~rom a supply connaction and control valve 66, mounted on the outer surface of rear panel ~8, via supply pipes 67a, 67b and 67c, to the rear ends o~ both heat exchan~ers 65a, 65b.
Return water and steam ~rom heat exchanger 65a is fedr via con~
duit 68a t to a steam trap and steam return member 70 on front pane~ 26. Return water and steam from hea~ exchanger 65b is ~ed, via conduit 68b, to member 70. A control box 71 above member 70 contains the thermostatic controls by which the temperature of the oven can be regulated.
z~
For exhausting air, vapors and f~es from the inter-ior of housing 20, a vertically disposed hoLlotr~, cylindrical, exhaust stack or duct 80 is provided in housing 20, as seen in Figs. 1~ and 2A. The stack protrudes through one roof panel 25 and projects down into the interior to terminate at mouth 83 in an area well below the level of fans 45, as shown in Fig. lA. The stack 80 is laterally offset rrom the first fan assembly 40 so as to be about midway or in the forwar~ inter-mediate portion along the passageway formed by the vestibule 30 and housing ~0. An exhaust fan 81 is disposed with its motor 82 in the upper end portion of duct 80. The lower end or mouth 83 is open and provides an intake port through which all air is drawn from the interior into the duct 80. For protection, a screen or grid 36 is disposed horizontally in the oven below blades 45.
In operation the oven of Fig. lA, lB, 2A, 2B, 3 and ~ is brought up to temperature and the motors 58 are energized to operate the fans 45. The objects 100 to be dried are then passed successively on conveyor 8S through the passagewa~r 35 in the direction of the arrows in Fig. 1~ and Fig. lB.
The fans 45 each direct the air in circular paths as shown in Fi~. 3, down onto the object 100 and then up througll the heat exchanger 65a or 65b which is adjacent to the particular fan 45. Thusr heated high ~relocity air is directed onto the object 100 so that it is dried quite quickly. Since the drying is proportional to the temperature of the air and its velocity over the object, the high volume of air, thus delivered, dries the object in a fraction of the time previously taken. The impelling of the air against the object to be dried reduces to a minimum ~7%1~
the boundary layer of the surface coating.
In the embodiments of Fiys. 5 and 6, it is seen that if there is a problem with low ceilings in a plant, the Mo~or 158 can be mounted by brackets 159 to a side panel 12~, adjacent its upper edge, so that the shaft 154 of the motor 159 protrudes about the surface of roof panel 125. Thus, the drive belt 156, which drives the fan shaft 143, extends over the roof panel 125 of the housing 120, closely adjacent and parallel to panel 125. The fan assemblies 40 are identical to fan assem~lies 40 and the shaft 143 thus dri~es the fan 145.
The remaining structure of Figs. 5 and 6 are other-wise identical to Figs. lA, lB, 2A, 2B, 3 and 4, however, the vestibule 30 is eliminated. In this embodiment, the heaters 165a and 165b are identical to heaters 65a and 65b and feed to a steam trap member 170 which is similar to trap ~ember 70~
The control box 171 on front panel 126 corresponds to control box 71.
In the embodiment of Figs. 7, 8 and 9, the oven is illustrated as having an inverted channel shaped housing 220 ormed of side panels ~2~ and roof panels 225. The housing 220 also has ront panels 226 defining an entrance opening of an open passageway 235 through the housing 220.
A p~urality of fan assemblies 240, identical to assemblies ~0, are disposed in and supported by the side panels 224 so that the ans 245 thereof, which are spaced inwardly of the inner suraces of pa~els 22~, direct the air, horizont-ally inwardly Erom both sides, as shown by the arrows 234 of Fig~ 7 and 9.
28~L
In the present embodiment, there are opposed vertical inner walls 231 from the floor to the roof of housing 220, in~
wardly parallel to the side panels or vertical walls 22~. Air can readily pass through these walls 231 as illustrated by arrows 234 in Fig. 9. End panels such as front panels 226 join the ends of walls 224 and 231 on both sides of housing 220, to define plenums 236.
The inner end of casing 241 of each fan assembly 240 protrudes into a circular opening in its associated inner wall 231 so that an annular shroud or cowling 232, carried by the wall 231, defines the opening surrounding the fan 245. A
grid or mesh cover 233 extends over each cowling 232.
The fan assemblies 240 in each side of housing 220 are disposed in parallel horizontal rows as shown in Fig. 8.
The fan assemblies 240 in each row are equally spaced from each other and are staggered with respect to the fan assemblies 240 o the adjacent hori20ntal row.
Furthermore, the ~an assemblies 240 on one side of housing 240 are staggered with respect to the fan asse~blies 240 on the other side thereof as shown in Fig. 9.
Carried in walls 231, below the fans 245 and their cowlings 232, are a plurality of steam heat exchangers 265.
Each o the heat exchangers 265 have a steam coil over which the airr entering the plenums 236 from the interior of housing 220, passes. The heat exchangers 265 are arranged between both walls 224 an~ 231 in rows, below ~he fans 245, as shown in Fig. 8.
7~
As seen best in Fig. 7 in the central portion o -the roof of housing 220 is the intake end 283 of an exhaust duct 280 which extends up a short distance and then horizontally transversely across the roof of housing 220 to terminate at and communicate ~ith ~he intake of a centrifugal blower 281 mounted on the roof adjacent on side wall 224 and driven by an electric motor 282 through belt 284. The blower 281 dis-charges, upwardly~
In operation of the oven of Figs. 7, 8 and 9, the 10 motors 258 of the fan assemblies 240 are energi~ed to rotate the fans 245 thereof and produce horizontally inwardly directed currents of air in alternate counter flow relationship, as shown by arrows 234 in Figs. 7 and 9. The fans 245 draw a slight`partial vacuum in the plenum chambers 236 so as to draw air into the chambers 236 through the wall 231 and some air over the coils of the heat exchangers 265. Thus, high velocity air is directed onto objects ~not shown) which are passed successively throu~h the interior o the housing 220 and be~
tween the opposed ban~s of Eans 245.
In the embodiment of Figs. 10 and 11, a closed gas ired oven is disclosed. This oven includes an inverted U-shaped ~ousing 320 with side walls 324 and a roof 325 formed of ~butting insulated panels and resting on the floor. Two spaced, longitud-inally centered, ans 345 carried by fan assemblies 340 direct air in a downward direction in the interior o the oven. Each fan assembly 340 is identical in construction to the fan Z~3~
assembly 40 and has an external motor 358 carried by bracket 359, driving a belt 356 to rotate the vertically disposed shaft 343 in casing 341 to rotate fan 345.
In the housing 320, the front and back are identical, each as the case may be. Doorjamb 331 in the wall 326 respec-tively support hinged opposed doors 332, by hinges 333, so that the entrance or exit opening may be closed or opened by manual manipulation of the doors 332.
Above the doors 332, a pair of spaced straight tracks 335 extend in parallel relationship, parallel to the walls 324 through the interior of the oven. The tracks 335 pass generally tangentially adjacent to and below the path of travel o the tips of fans 345. Qb]ects (not shown) to be dried are suspended from the tracks 335 and passed into the oven and then out of the oven.
Adjacent to one side wall 324 is a vertical exhaust stack 380 which has a mouth or exhaust openin~ 383 at one side adjacent its bottom. 1'he opening 383 communicates with the interior of the housing 320 at a level well below fans 345.
20 The stack 380 protrudes above the roof 325 and is closed at both ends by end plates 384 and 386. A sidewise extending duct 387, at the upper end portion of stack 380 communicates with the intake o~ a centrifugal exhaust blower 381 driven by motor 382. The blower 381 is mounted on the roof 325 and dis-charges upwardly.
~18~7~8~
A substantia] portion of the air introduced into ~he oven or housing 320 is through an air blo~ler 360 of a heater or burner assembly 365. The blower 360 is driven b~ a motor 361 and discharges air into a gas burner 362 which directs a mixture of air and gas as a flame sidewise through an opening 363 in side wall 324. The burner assembly 365 is carried on the upper central portion of a side wall 324, as shown in Figs.
10 and 11, so as to direct the flame into the interior of the housing 320 above the plane of rotation of the fans 345 and mldway between the fan assemblies 340. Thus, the fans 345 will direct the heated air downwardly onto the objects to be dried in the oven. Gas for the burner 362 is supplied via a gas valva 364 through gas manifold 366 and pipes 367.
In the embodiment o~ Figs. 12 and 1~ a gas fired oven is disclosed. This oven has the inverted U-shaped housing 420, provided with opposed vertical side walls 424~ the upper edges oE which are joined by a flat roof 425. The oven has at its ends, smaller entrance and exit vestibules, similar ~o the entrance vestibule 430 which is connected to the end walls 426 o~ the housing 420. The vestibule 43Q is a tunnel like member, identical in construction to vestibule 30 of Figs. lA and 2~. Thus,more detailed disclosure is not deemed necessary. Su~ice it to state that successive objects tnot shown) pass through the front vestibule 430, then pass throu~h the interior of housing 420 and, thence, through the ~ear vestibule tnot shown) to the exterior.
Carried by the roof 425 and disposed at equa~l~ spaced intervals along the longitudinal centerline of th~ housinc3 420 are the fan assemblies 440 which are each identical to the fan assembly 40. Thus each has a vertical shaft 443 rotated by an external motor 458 to drive a fan 445 for rotation about the vertical axis of the shaft 443. Thus, a high velocity downdraft in housing 420 is generated.
Disposed longitudinally along the interior common edge between the roof 425 and one wall 424 is a rectangular air distribution duct 465. This duct 465 e~tends through~
out the length of the interior of the housing 420, from one end wall 426 to the other. Approximately ~idway between adjacent fan assemblies 440, are sidewise opening discharge ports 466 in the duct 465.
In the central portion and extending transversely across the roof 425 is a rectangular heater duct 467~ One end portion of duct 467 opens downwardly and communicatesr through roof 425, with a central port in the air distribution duct 465. The other end portion of duct 467 terminates ~0 in an end plate 468 through which a gas burner 469 projects.
A pipe 470 supplies gas to burners 469 and an air blower 471 supplies air for producing a combustible mixture which is dischar~ed into a hollow tubular open ended flame tube 472 wi~hin the interior of duct 467.
~ 7213~
The other end of duct 467 is closed by a supply fan 473. The function of supply fan 473 is to accelerate the pro-ducts of combustion received by duct 467 as they pass from duct 467 to duct 465 so that they are dist~ibuted to the long-itudinally spaced discharge ports 466. An access door 474 is provided in the side of duct 467.
For exhausting air from the interior of housing 420, a vertically disposed exhaust duct 480 is provided. This duct 480 protrudes through the roo 425 and downwardly, adjacent the side wall 424 which is opposite to duct 465. The open lo~er end or mouth 483 of duct 480 terminates well below the horizon-tal plane of fans 445. The upper end of exhaust duct 480 has an end plate 484 which receives a smaller cylindrical duct 486 provided with a transversely pivotally mounted flapper valve 485 which functions as a damper.
An exhaust blower 481 driven by a motor 482 has its suction side connected via condu~t 488 to the upper side o the end portion of duct 480. The blower 481 exhausts upwardly.
The setting of damper 485 determines the amount of air withdrawn via duct 480 rom the interior of housing 420.
In Figs. 12 and 13 the air is circulated as indicated by arrows 490 for drying the objects tnot shown) disposed in the interior of the housing 420.
8~
The next ernbodiment is depicted in Figs. 14 and 15, wherein an inverted U-shaped housing 520 is provided, the housing 520 having side walls 524 and a roof 525. Objects to be dried enter the housin~ 520 through an appropriate opening 527 in the front 526 of the housing 520. They then travel longitudinally through the housing 520. Disposed o~
opposite sides of the path of travel of the object through the housing 520 are a plurality of equally spaced fan assemblies 540a and 540b which are substantially identical in construction to the ~an assembly 40, except that the ~an assembly 540a rotates the fan 545a so as to draw air into it and the fan assembly 540b rotates its blade 545b in a direction to thrust air away from the an assembly 540b, as illustrated by arrows 534 in Fig. 14.
Each fa~ assembly 540a which is disposed in one side 524, has an opposing ~an assembly 540b transversely opposite to it and supported by the other side wall 5~4.
PreEerably, the an assemblies are arranged in rows as shown in Fig. 15, one row bein~ disposed above the other. In ~uch a row, the an assemblies 540a and 540b are arranged alternately. Also, the Ean asse~nblies 540a are arranged verti-cally one above the other and the an assemblies S40b are likewise arranged one above the other on a sin~le side.
Disposed between adjacent ~an assemblies 540a and 540b are heat exchangers 565 which are supplied with steam and have steam coils in substantially the same manner as de-scribed ~or the heat exchangers 65a and 65b. These heat exchangers 565 are mounted vertically to the inside ~37;~
surfaces of walls 524 and extend forwardly so as to terrninate in a position forwardly of the plane of the blades of ans 545a and 545b of their associated fan assemblies 5~0a and 540b. Thus, the air drawn in by these fans 545a is directed through the heat exchan~ers 565 which are disposed on one or both sides of the fan 545a and this air is delivered then to the fans 545b so as to be discharged into the interior of the housing 520 and against the object to be dried.
The next embodiment of the present invention is de-picted in Figs. 16a, 16b, 16c, and 17. In this embodimentr the object to be dried is subsequently cooled so that it can be handled as soon as it emerges from the drier~ Referring specifically to Fig. 16a, it is seen that the housin~ 620 is formed o a pair of vertically disposed parallel opposed side walls 624 joined along their upper edge by a roof 625 as shown in Fig. 17. Thus, like the preceding embodiments the housin~
6~0 is an inverted U-shaped member. Its ~ront end, however, is closed by an end wall 627 and one~side thereof, adjacent to the end wall 627 is open to communicate ~ith a ves~ibule, denoted ~enerally by numeral 630. The vestibule 630 is sub-stantially identical in construction to the vestibule 30 and hence no detailed description is required e~cept to state that there is an e~haust fan, denoted ~enerally by numeral 635 disposed in the roof 632 of the vestibule 630. The vestibule 630 is open at the front and receives successive objects ~not shown) which are moved by a conveyor tnot 6hown) along a path of travel, denoted by the broken line 636.
~B7~
Upon passing through the vestibule 630, the objects are fed successively sidewise into the front end o~ the hous$ng 620 and, thence, longitudinally along the path of travel de~oted by the broken line 636 as shown in Fig. 16a. Along this path of travel are a plurality o fan assemblies, denoted by the numeral 640. Each fan assembly is carried by the roof 625 so that its fan 645 is rotated about a vertical axis and is spaced below the inner surface of the roof 625. Since the fan assembly 640 is identical to the fan assembly 40, no more detailed description is provided o the same except to state that the fan assemblies 640 are ar~anged in two parallel longitudinally extending rows parallel to the side walls 624 and are respectively staggered so that the fan assembly 640 in one row is adjacent one wall 624 and the next fan assembly 640 is adjacent the other wall 624.
Between the first two fan assemklies 640 in one row, as seen in Fig. 16a, heater assembly, denoted generally by the numeral 665, is provided in the roof 625. This heater assembly 665 is a direct ired burner and includes a combustion 20 air blower 666 and a burner body 667 which receives the air and gas to produce a combustible mixture and directs the product o~ combustion downwardly through the roo~ 625 so that the flame burns within the interior of the housing 620. Addi~ional heaters 665a, 665b, and 665c are disposed in staggered relationship in the roof 625, as shown in Figs. 16a and 16b.
The burner assembly 665a is disposed between the second and third fan assembly 640 on the right side and the burner assembly 2~
665b is disposed between the 4th and 5th fan assembl~ 640 on the lef-t side. The burner assembly 665c is disposed be-tween the last two fan assemblies 640 on the right side of the oven. Each provides a combustible mixture of gas and fuel in a downwardly directed flame.
It will be observed in Fig. 17 that all fans 645 of the fan assembly 640 are disposed in a common horizontal plane spaced below the lower surface of the roof 625. A pro-tective screen 670 is disposed in spaced relationship parallel to and below the plane of ans 645, the screen 670 being sup-ported by the side walls 624, as illustrated in Fig. 17.
Cowling 668 supported by the screen 670 respectively surround the fans 645.
Connected in tandem to the discharge or rear end of the housing 6~0 is a second vestibule, denoted by the numeral 630a in Fig. 16c~ This vestibule 630a has a roof 632a supported by side walls 631à. ~t also has an exhaust fan 635a in the central portion of the roof 632a. The walls 631a are extensians of the walls 624 while the roof 632a is 2n in a common horizontal plane with the roof 632 and is at approximately the same hèight as the protective screen 670.
Any excess air, fumes, vapor and gases which accumu-late in the housing 620 are withdrawn by the exhaust fans 635 and 635a.
- 2~ -~18~Z !3~
Connected in tandem to the discharge or rear ~nd of the vestibule 630a is a cooling chamber, denoted cJenerall~
by the numeral 680. This cooling chamber 680 has side walls 681 and a roof 682. It too is an inverted U-shaped member which corresponds to the cross sectional dimensions o~ the housing 620. It too is provided with stag~ered cooling fan assemblies 74~ mounted through the roof 682. ~ach fan assembly 740 is identical to the fan assembly 40 and has a fan 745 disposed in a common horizontal plane which coincides with the common ho~i~ontal plane of the fans 645. It too has a protective screen ~not shown) and cowling 768 for the fans 745. Since there is no heating element associated with the fans 7~0, they function to quite rapidly cool the surfaces of the objects which pass therebeneath. Hence, the objects are successively discharged from the rear end 683 of the cooling chamber 680. It will be understood by those skilled in the art, that if desired, coolin~ coils in a heat exchanger, such as heat exchanger 685, may be incorporated in the roo 682 of the chamber 680, if desired. Thus t additional coolin~ of the objects may be readily pro~ided.
In the embodiments shown in Fig. 18 o~ the present invention, still another form o the present invention is depicted. This oven is or drying ~reshly painted pipes or other cylindrical members as they are passed rom one ènd to the other through the housin~, denoted ~enerally by ~he numeral 820. In more detail, the housing 820 has side walls 824 and a roof 825 and is closed at both ends by end walls which are substantially identical. Thus, only one end wall 826 is illustrated.
7Zl~
Within the central portion of the end ~,/all 826 i~
a square or rectangular central opening, over which extend3 a sheet metal plate 827, being secured to the end wall ~26 by means of screws 828. A plurality of juxtaposed circum~eren-tially disposed flexible closure plates 829 are secur~d to the plate 827 so as to protrude into the opening defined by the circular inner edge of the plate 827. The purpose of the flexible closure plates are simply to reduce the effective diameter of the opening in the plate 827 so that there is very little space between the surface of a cylindrical object such as a piece of pipe which has a Diameter D and is fed from one end of the housing 820 through to the other end of the housing 820, being supported externally at an appropriate hei~ht.
Within the housing 820 are a pair of opposed fans 845 which are disposed on opposite sides of the path of travel of the object. These fans 845 are rotated about aligned horizontal axes of their shafts 843. The fans 845 and shafts 843 form elements of the fan assemblies 840 which are identical to the fan assemblies 40 and are supported, as illustrated in Fig. 18, by the side walls 824. A heater, denoted generally by the numeral 865, includes a blower 866 and a burner 867.
The burner 867 is mounted in one of the end walls 826, as illustrated in Fig. 18, and directs the mixture of either gas or oil and a~r into the interior of the housing 820 in essentially a hori~ontal path below the roof 825 and above .~ !37Z~3~
the path of travel of the object. Thus, the ~ans ~5 draw the heated products of combustion in pairs as ilLustr~ted by the arrows 868 in Fig. 18 and direct this heated gas against opposite sides OL the object, simultaneously.
In the embodiments hereinbefore described, it is important -that the fans 45, 145, 245, 345, 445, 545, 645, 745 and 845 be spaced from their associated ~all or roof by at least about two feet and not more than about six feet. By so positioning the fans, there is very little vacuum drawn on the back sides Of the fans in delivering a very high velocity of air. The hea-~ers which are disposed in various rela-tionships to the fans are all arranged so that the air is heated imm~diately prior ~o being delivered to the back sides of the fans. Further-more~ the return velocity of the air where it, at times,is again heated by the heating elements, is quite low~ thereby enabling substantial heat transfer before the air is again delivered by the fans at high velocity. Since the velocity of the air is low, on return, there is little trash picked up from the Eloor. The heat can be fed into the oven at substantially any place and will be quite readily disseminated throu~hout the oven. Therefore, the oven is quite uniformly heated.
~Ieat introduced, however, should be generally transverse to the path o~ travel of the propeller or fan blades.
In the fan assembly 40, the inner bearing, which permits both rotational movement and a~ial movement, is cooled by the flow of air in the casing 41 and the shaft is, likewise, 3L~L1 37z~
cooled. The air is introduced from the exterior down past the shaft and past the inner bearing, due to the low prcssuxc or slight vacuum generated on the back side of the fans.
Since the air is delivered quite rapidly and at hi~h velocity of the surfaces to be dried, there is little need for heating the oven beyond about 900F to achieve very rapid drying of the surfaces of the objects.
Thus, aluminized steel plates may be utilized for the panels from which the housings are made. In the event that temperatures from about 900F to about 1800F are contemplated for the interior of the oven, it is recommended that stainless steel be used for the panels and that Incone ~ blades be employed for the fans.
As seen in Figs. 19 and 20, a modified form of fan assembly 940 which is particularly suited to low temperature ovens, i.e. ovens which do not heat above about 350F is shown.
The fan assembly includes a hollow tubular sleeve or casing 941 which is rectangular in cross-section~ The sleeve 941 is preerably made up of opposed channel members 941a, 941b, the edges of which have opposed abutting 1anges 942 bolted together by spaced bolts and nuts 944.
A motor 958 is secured in the inner end portion of the sleeve 941 and has an outwardly protruding motor shaft 943 protruding inwardly; perp~ndicularly to the wall 924. The end of shaft 943 is provided with a rotary or bladed propeller 945 which includes a collar 946 secured to a hub 947 and blades 948 which radiate from the hub 947. In front of the fan 945 7~1 is a protective screen 970 supported by the ~,~alls o~ thc housing 920.
The outer end of sleeve 941 protrudes throucl~ a side wall or roo~ wall 92~ and is supported in place by anqle iron brackets 952 and 953. Since the outer end of sleeve ~1 is open to the ambient air, the rotation of the fan 945 by motor 958 will generate a draft through the sleeve 343, t~rough the motor 958 and into the interior of the housing ~20. This flo~
of air through motor 958 keeps the motor 958 cool.
A feature o~ the invention is the ability to provide temperature zones within a single oven. This is accomplished by using independent temperature controls on the steam coils or the gas or oil burner~ The benefit of beina able to zone the oven is that the most efficient rate Gf heat transfer for a specific portion of the cure cycle can be provided.
In addition to zoning the temperature, the velocity at which the air is impinged on the processed part or object can also be zoned by varying the RPM's of the fans throughout the length of the oven.
I have found from actual tests that the heat transfer o the ovens discussed above are from 5 to 10 times ~reater or faster than the heat transfer o~ ovens with only limited circulation. Thus, unusually fast drying of surfaces of objects is achieved. Through -the high velocity of air delivered by the fans against the objects, the boundary layer is minimized and the solvent of paints is quite rapidly removed from the paint so that the painted surfaces are quite rapidly dried.
It will be understood that while I have disclosed the use of steam coils and the use of gas or oil burners, 7Z~
electric heating coils may be used in place of the steam colls, if desired and any combination of steam, electric, oiL or gas heating may be employed, if desired.
It will be obvious to those skilled in the art that many variations may be made in the embodiments here chosen for ~he purpose of illustrating the present invention and full result may be had to the doctrine of equivalents without departing from the scope of the present invention as defined by the appended claims.
~87~
electric heating coils may be used in place of the steam coi.ls, if desired and any combination of steam, electric, oiL or gas heating may be employed, if desired.
It will be obvious to those skilled in the art that many variations may be made in the embodiments here chosen for the purpose of illustrating the present invention and full result may be had to the doctrine of equivalents without departing from the scope of the present invention as defined by the appended claims.
- ~8 -
In the past ovens have been used to dry paint and other coatings on appliances, furniture and automobile bodies and other objects and articles of manuacture. In some instances electric and gas Eired infra red heaters have been used Eor the heat source in these ovens. ~ther ovens have used air as the heat transfer medium with little or no turbulence generated around the object to be heated (free convection oven). other ~0 ovens have employed turbulent air or air that is discharged at relatively high velocity. In previous applications where turbulent air was used it has been necessary to develop static pressures by the use of centrifugal fans in order to develop the relative high discharge velocity required. This method of generating turbulence requires large horse power.
Exhaust fans are also quite common where painting is being done to remove the fumes of the paint and the air which carries the paint.
21~1 SUMMARY OF THE I~;lV~:~lTION
In one aspect the lnven-tion ~ertains to a hiqh turbulence heat transfer oven Eor drying objects, includin~ a housing having a continuous common essentially open interior throuah which objects to be dried are passed along an open path of travel and fan means disposed at spaced intervals along the path and in the common open interior of the housing for cooperating in producing a circulation of air in the interior from the front side of each of the fan means toward the objects and thence arouncl to the back sides o~ the fan means. Each ~an means directs air against the objects and spaced heating means along the path of travel provide for heating only a portion of the air as it is returned to the back sides of each of the fan means for inter-mixing with the air in the essentially open interior. Control means may be provided for individuall~, respectively controlling the amount of heat delivered by the heating means. Al~ernatively, control means may be provided for individuall~, respectively controlling the speed of the fan means.
Another aspect of the invention pertains to an oven :Eor drying objects d~spnsed therein and haviny heating means, ~herein the housing having a wall deines an interior through which objects to be dried pass. A fan assen~ly is carried by the wall, the an asse~bl~ including a hollow tubular sleeve protruding through and supported by the wall. A motor is in one end of the sleeve and the sleeve is open for the passage of air through the motor, the motor having a shaft protrudirlg from the sleeve, with a fan on the end of the shaft and within the housing.
~0 rlore particularly, disclosed is an oven having walls through which shafts, supported by fixed sleeves, project.
~37~
Radially extending propel]er blades are pro~ided on the ends of the shafts. The blades are spaced from the ~,/alls and direct air toward the surface which is to be dr:ied. In one embodiment, heat exchangers, which carry steam, are disposed on ahout the same Plane as the blades so as to heat the air passing to the back slde of the blades. Another embodiment shows the fans in staggered relationship. Sti]l another embodiment shows the fans operation in alternate directions and heaters between the fans so that the exhaust of one fan delivers air through the heater to the next fan.
Other embodiments teach gas fired heaters discharging to the back side of the fans and fixed within a duct for heating air delivered to the fans.
In operation, the apparatus of the pxesent invention moves Iarge volumes of air over th~ surfaces to be dried with no appreciable back pressure and with great efficiency in the use of power. The surfaces to be dried are thus heated ~uite rapidl~. Since the air is not blown toward an entrance or exit opening through which the object passes, and air is exhausted from wi~hin the oven, there are no appreciable losses of heat to the interior of a fac-tor~ and no appreciable contamination of air in the factory. Thus, no ap~reciable sealing of the oven is necessary.
The oven can be quite readil~ and easil~ zoned bath as to zones o~ diEerent temperature and ~ones of different air velocity. The cost o~ producing and operating the ovan is qui~e nominal since small motors are used as opposed to the large motors used ~ centrifugal blowers.
Other aspects, Eeatures and advantages ~f the present inven-tion will ~ecome apparent from the ollowing description when taken in conjunction with the accom~an~ing drawings where like characters of reference designate corresponding ~arts thxoughout the several views.
~7~
BRIEF DESCRIPTION OF THE DRAWING
Fig. lA is a side elevational vie~" of a portiorl of a form of oven for drying the surfaces of objec-ts, the oven being constructed in accordance with the present invention;
~ ig. ls is a side elevational view of the remainder of the oven shown in Fig. lA;
Fig. 2A is a top plan view of that portion of the oven shown in Fig. lA;
Fig. 2B is a top plan view of that portion of the oven shown in Fig. lA;
Fig. 3 i5 an end view of the front end of the oven shown in Figs. lA, lB, 2A and 2B;
Fig. 4 is an exploded perspective view of one of tne fan assemblies o~ the oven shown in Figs. lAr lB, 2Ar 2B and 3;
Fig. 5 is an end elevational view of another form of the oven of the present invention;
Fig. 6 is a fragmentary top plan view of the oven shown in Fig. 5;
Fig. 7 is an end elevational ~iew of still another form of oven of the present invention;
Fig. 8 is a fragmentary side elevational view of the oven shown in Fig. 7;
Fig. 9 is a top plan view o the oven shown in Fi~s.
7 and ~;
Fig. 10 is an end elevatlonal ~iew o another form o oven of the prasent invention;
Fig. 11 is a fragmentary side elevational view of the oven sho~ in Fig. 10;
Fig. 12 is a fragmentary side elevational view of still another oven of the present invention;
Fig. 13 is an end view of one end of the oven shown in Fi~. 12;
~37Z~:~
DESCRIPTION OF THE PREFERRED EMsoDIMENTs -Referring now in detail to the embodiments chosen for the purpose of illustrating the present invention, numeral 20, in Figs. lA, lB, 2A, 2B and 3, denote generally an inverted U shaped or channel shaped, oven housing or casing. The housing 20 includes abutting side panels 24 secured side to side to form opposed, parallel side walls 21 while abutting top panels 25, secured together in side to side fashion form the top wall 22 o the oven. Each o panels 24 and 25 includes appropriate sheets of insulation ~7 disposed within the interior o the panel and innar and outer metal sheets 27a and 27b sandwiching the insulation sheets 27.
At the ront end of the housing 20 there is an entxallce vestibule, denoted generally by numeral 30. This entrance vestibule 30 is also an inverted U-shaped or channel shaped member but is o gn~llerdimensions than the housing 20. The vestibule 30 thus has abutting opposed parallel, rectanguiar, upright, side panels 31 resting by thèir lower edges on the floor and top panels 32 joining the upper edges of the side panèls 31 to orm a roo.
3L~L8~
The housing 20 is provided ~ith a front ~aneL or wall 26 closing the front of housing 20, excep~ ~or an access opening defined by inner edges of the panel 26. The inner edges of the vestibule 30 are connected to the inner edges of the panel 26 while the outer end of the vestibule 30 is open to provide a passageway through the vestibule 30 and into the larger housing 20.
The housing 20 also has a back panel or wall 28 which has an exit opening of the same dimensions as the access opening of panel 26. Thus, an unobstructed passageway 35 is provided through which successive objects 100, carried on a conveyor 85, are fed or drying by the oven.
According to the present invention, drying is accom-plished by heated high velocity air driven by a plurality of fan assemblies 40 spaced successively along the pathway or passageway 35.
As best seen in Fig. 4, each ~an assembly 40 includes a hollo~ rectangular or square tubular casing or slee~e 41, open at both ends.~ Secured within the inner end of the casing 41 ~ is an inner or lower bearing 42 which journals a central drive shaft 43. Secured within the outer end of the casing 41 is an outer bearing alignèd with inner bearing 42 and also receiving shat 43. This outer bearing, as illustrated, i~ a thrust bearing, includes opposed bearing sections 44a and 44b. The lower or inner bearing 4~ journals the shaft 43 for both rota-tional movement and axial movement whereby the shat 43 may expand and contract with heat changes.
372~
The shaft 43 extends inwardl~ beyond beariny 42 and its inner end is provided with a bladed air propeller, fan or impeller 45. The propeller 45 includes a central hub formed of a collar 46 secured to the end of the shaft 43 and a square hub plate 47. In the present èmbodiment four flat paddle li~e blades 48 radiate from the hub 47, each blade 48 being disposed at an angle to the shaft 43 to drive the air inwardly when shaft 43 is rotated in a counterclockwise direction as viewed in Fig. 4.
For cooling the shaft 43 and bearing 42, a pair of holes 49a and 49b are provided in the casing 41 respectively adjacent the bearing formed by segments 44a, 44b and bearing 42. The suction or aspirating effect created at its back side by fan 45 induces a flow of air as indicated by the arrows 50 in Fig. 4.
The sleeve or casinq 41 projects through an appropriate hole in panel 25 and ls secured b~ an intermediate portion to one of the panels 25. For this purpose, the casing 41 has a central perime~ral flange 51 which abuts the outer surface of panel 25. T~o opposed, angle iron, brackets or straps 52, passing on opposite sides o~ the casing 41 and respectively over opposite port~ons of flange 51, extend over the surface of panel 25 and are secured by riVets or bolts 53, thereto.
Thus, the casing 41 is disposed in a fixed position extending perpendicularly through the roof panel 25 and the hole 49a is disposed externally of the housing 20.
7~
The outer end of the shaft 43 is provided ,lith a puLle-~
or sheave 55 clriven by belts 56 from a pulle~ or sheave 57 on the shaft 54 of an electric motor 58. A motor mountiny bracket 59, secured to an outer suLface of casing 41, extends Late~all~
from the casing 41 and is provided, at its outer end po~tion, with a motor mounting plate 60. Bolts (not shown) mount motor 58 on plate 60 so as to dispose its shaft 54 parallel to and spaced from shat 43. Thus, motor 58 is spaced away from and outwardly of panel 25. Also, the fan 45 is spaced an appreciable distance inward from the inner sheet 27b of panel 25.
In the present embodiment, three longitudinally spaced fan assemblies 40 are provided for housing 20~ the sha~ts 43 thereof being disposed along a lonqitudinal center line of the roof or top 22, as seen in Figs. 2A and 2B. The central fan assembly 40 is midway o housing 20 and the axes of the front and back fan assemblies 40 are equidistant from the axis o the central fan assembly 40 preferably being respectively about half the distance from the axis of the central asse~bly 40 to the ront and back panel 26 or 28, as the case may be.
The shats 43 of assemblies 40 are, thus, disposed vertically parallel to each other and are equally spaced longitudinally along the pathway o the objects 100~ Each o ~he shafts 43 disposes its fan or propeller 45 in a common hori~ontal plane, parallel ~o roo wall 22, and generally coincides with the plane o~ tha roo panels 32, as shown in Fig. 3. The diameter o each an or propeller 45 is about one-ourth to about three-ourths the width o the housing 20 ~rom side wall 21 ~o side wall 21. Preferably the diameter is about one-hal such distance.
Within the housing 20 and outboard on opposite sides of the fans or propellers 45 o~ the three assemblies 40 are a pair of parallel, longitudinally extending, heat exchangers 65a, 65b. These heat exchangers 65a and 65b are in staggered longitudinally overlapping relationship and each is a right prism or rectangular box-like member containing steam coils over which the air circulates.
As seen best in Figs. 2A and 2B ~he heat exchanger 65b extends along the right side of the front fan 45 and middle lQ or central fan 45. The heat exchanger 65a is disposed along the leEt side of the middle or central fan 45 and the rear fan 45. Thus, air circulated by the front fan 45 will pass essentially through only the hea~ exchanger 65b, the air circu-lated b~ the central fan 45 will circulate through both heat exchangers 65a and 65b, and the air Girculated by the rear Ean 45 will pass essentially through only the rear heat e~changer 65a.
Steam ls supplied to both heat exchangers 65a and 65b ~rom a supply connaction and control valve 66, mounted on the outer surface of rear panel ~8, via supply pipes 67a, 67b and 67c, to the rear ends o~ both heat exchan~ers 65a, 65b.
Return water and steam ~rom heat exchanger 65a is fedr via con~
duit 68a t to a steam trap and steam return member 70 on front pane~ 26. Return water and steam from hea~ exchanger 65b is ~ed, via conduit 68b, to member 70. A control box 71 above member 70 contains the thermostatic controls by which the temperature of the oven can be regulated.
z~
For exhausting air, vapors and f~es from the inter-ior of housing 20, a vertically disposed hoLlotr~, cylindrical, exhaust stack or duct 80 is provided in housing 20, as seen in Figs. 1~ and 2A. The stack protrudes through one roof panel 25 and projects down into the interior to terminate at mouth 83 in an area well below the level of fans 45, as shown in Fig. lA. The stack 80 is laterally offset rrom the first fan assembly 40 so as to be about midway or in the forwar~ inter-mediate portion along the passageway formed by the vestibule 30 and housing ~0. An exhaust fan 81 is disposed with its motor 82 in the upper end portion of duct 80. The lower end or mouth 83 is open and provides an intake port through which all air is drawn from the interior into the duct 80. For protection, a screen or grid 36 is disposed horizontally in the oven below blades 45.
In operation the oven of Fig. lA, lB, 2A, 2B, 3 and ~ is brought up to temperature and the motors 58 are energized to operate the fans 45. The objects 100 to be dried are then passed successively on conveyor 8S through the passagewa~r 35 in the direction of the arrows in Fig. 1~ and Fig. lB.
The fans 45 each direct the air in circular paths as shown in Fi~. 3, down onto the object 100 and then up througll the heat exchanger 65a or 65b which is adjacent to the particular fan 45. Thusr heated high ~relocity air is directed onto the object 100 so that it is dried quite quickly. Since the drying is proportional to the temperature of the air and its velocity over the object, the high volume of air, thus delivered, dries the object in a fraction of the time previously taken. The impelling of the air against the object to be dried reduces to a minimum ~7%1~
the boundary layer of the surface coating.
In the embodiments of Fiys. 5 and 6, it is seen that if there is a problem with low ceilings in a plant, the Mo~or 158 can be mounted by brackets 159 to a side panel 12~, adjacent its upper edge, so that the shaft 154 of the motor 159 protrudes about the surface of roof panel 125. Thus, the drive belt 156, which drives the fan shaft 143, extends over the roof panel 125 of the housing 120, closely adjacent and parallel to panel 125. The fan assemblies 40 are identical to fan assem~lies 40 and the shaft 143 thus dri~es the fan 145.
The remaining structure of Figs. 5 and 6 are other-wise identical to Figs. lA, lB, 2A, 2B, 3 and 4, however, the vestibule 30 is eliminated. In this embodiment, the heaters 165a and 165b are identical to heaters 65a and 65b and feed to a steam trap member 170 which is similar to trap ~ember 70~
The control box 171 on front panel 126 corresponds to control box 71.
In the embodiment of Figs. 7, 8 and 9, the oven is illustrated as having an inverted channel shaped housing 220 ormed of side panels ~2~ and roof panels 225. The housing 220 also has ront panels 226 defining an entrance opening of an open passageway 235 through the housing 220.
A p~urality of fan assemblies 240, identical to assemblies ~0, are disposed in and supported by the side panels 224 so that the ans 245 thereof, which are spaced inwardly of the inner suraces of pa~els 22~, direct the air, horizont-ally inwardly Erom both sides, as shown by the arrows 234 of Fig~ 7 and 9.
28~L
In the present embodiment, there are opposed vertical inner walls 231 from the floor to the roof of housing 220, in~
wardly parallel to the side panels or vertical walls 22~. Air can readily pass through these walls 231 as illustrated by arrows 234 in Fig. 9. End panels such as front panels 226 join the ends of walls 224 and 231 on both sides of housing 220, to define plenums 236.
The inner end of casing 241 of each fan assembly 240 protrudes into a circular opening in its associated inner wall 231 so that an annular shroud or cowling 232, carried by the wall 231, defines the opening surrounding the fan 245. A
grid or mesh cover 233 extends over each cowling 232.
The fan assemblies 240 in each side of housing 220 are disposed in parallel horizontal rows as shown in Fig. 8.
The fan assemblies 240 in each row are equally spaced from each other and are staggered with respect to the fan assemblies 240 o the adjacent hori20ntal row.
Furthermore, the ~an assemblies 240 on one side of housing 240 are staggered with respect to the fan asse~blies 240 on the other side thereof as shown in Fig. 9.
Carried in walls 231, below the fans 245 and their cowlings 232, are a plurality of steam heat exchangers 265.
Each o the heat exchangers 265 have a steam coil over which the airr entering the plenums 236 from the interior of housing 220, passes. The heat exchangers 265 are arranged between both walls 224 an~ 231 in rows, below ~he fans 245, as shown in Fig. 8.
7~
As seen best in Fig. 7 in the central portion o -the roof of housing 220 is the intake end 283 of an exhaust duct 280 which extends up a short distance and then horizontally transversely across the roof of housing 220 to terminate at and communicate ~ith ~he intake of a centrifugal blower 281 mounted on the roof adjacent on side wall 224 and driven by an electric motor 282 through belt 284. The blower 281 dis-charges, upwardly~
In operation of the oven of Figs. 7, 8 and 9, the 10 motors 258 of the fan assemblies 240 are energi~ed to rotate the fans 245 thereof and produce horizontally inwardly directed currents of air in alternate counter flow relationship, as shown by arrows 234 in Figs. 7 and 9. The fans 245 draw a slight`partial vacuum in the plenum chambers 236 so as to draw air into the chambers 236 through the wall 231 and some air over the coils of the heat exchangers 265. Thus, high velocity air is directed onto objects ~not shown) which are passed successively throu~h the interior o the housing 220 and be~
tween the opposed ban~s of Eans 245.
In the embodiment of Figs. 10 and 11, a closed gas ired oven is disclosed. This oven includes an inverted U-shaped ~ousing 320 with side walls 324 and a roof 325 formed of ~butting insulated panels and resting on the floor. Two spaced, longitud-inally centered, ans 345 carried by fan assemblies 340 direct air in a downward direction in the interior o the oven. Each fan assembly 340 is identical in construction to the fan Z~3~
assembly 40 and has an external motor 358 carried by bracket 359, driving a belt 356 to rotate the vertically disposed shaft 343 in casing 341 to rotate fan 345.
In the housing 320, the front and back are identical, each as the case may be. Doorjamb 331 in the wall 326 respec-tively support hinged opposed doors 332, by hinges 333, so that the entrance or exit opening may be closed or opened by manual manipulation of the doors 332.
Above the doors 332, a pair of spaced straight tracks 335 extend in parallel relationship, parallel to the walls 324 through the interior of the oven. The tracks 335 pass generally tangentially adjacent to and below the path of travel o the tips of fans 345. Qb]ects (not shown) to be dried are suspended from the tracks 335 and passed into the oven and then out of the oven.
Adjacent to one side wall 324 is a vertical exhaust stack 380 which has a mouth or exhaust openin~ 383 at one side adjacent its bottom. 1'he opening 383 communicates with the interior of the housing 320 at a level well below fans 345.
20 The stack 380 protrudes above the roof 325 and is closed at both ends by end plates 384 and 386. A sidewise extending duct 387, at the upper end portion of stack 380 communicates with the intake o~ a centrifugal exhaust blower 381 driven by motor 382. The blower 381 is mounted on the roof 325 and dis-charges upwardly.
~18~7~8~
A substantia] portion of the air introduced into ~he oven or housing 320 is through an air blo~ler 360 of a heater or burner assembly 365. The blower 360 is driven b~ a motor 361 and discharges air into a gas burner 362 which directs a mixture of air and gas as a flame sidewise through an opening 363 in side wall 324. The burner assembly 365 is carried on the upper central portion of a side wall 324, as shown in Figs.
10 and 11, so as to direct the flame into the interior of the housing 320 above the plane of rotation of the fans 345 and mldway between the fan assemblies 340. Thus, the fans 345 will direct the heated air downwardly onto the objects to be dried in the oven. Gas for the burner 362 is supplied via a gas valva 364 through gas manifold 366 and pipes 367.
In the embodiment o~ Figs. 12 and 1~ a gas fired oven is disclosed. This oven has the inverted U-shaped housing 420, provided with opposed vertical side walls 424~ the upper edges oE which are joined by a flat roof 425. The oven has at its ends, smaller entrance and exit vestibules, similar ~o the entrance vestibule 430 which is connected to the end walls 426 o~ the housing 420. The vestibule 43Q is a tunnel like member, identical in construction to vestibule 30 of Figs. lA and 2~. Thus,more detailed disclosure is not deemed necessary. Su~ice it to state that successive objects tnot shown) pass through the front vestibule 430, then pass throu~h the interior of housing 420 and, thence, through the ~ear vestibule tnot shown) to the exterior.
Carried by the roof 425 and disposed at equa~l~ spaced intervals along the longitudinal centerline of th~ housinc3 420 are the fan assemblies 440 which are each identical to the fan assembly 40. Thus each has a vertical shaft 443 rotated by an external motor 458 to drive a fan 445 for rotation about the vertical axis of the shaft 443. Thus, a high velocity downdraft in housing 420 is generated.
Disposed longitudinally along the interior common edge between the roof 425 and one wall 424 is a rectangular air distribution duct 465. This duct 465 e~tends through~
out the length of the interior of the housing 420, from one end wall 426 to the other. Approximately ~idway between adjacent fan assemblies 440, are sidewise opening discharge ports 466 in the duct 465.
In the central portion and extending transversely across the roof 425 is a rectangular heater duct 467~ One end portion of duct 467 opens downwardly and communicatesr through roof 425, with a central port in the air distribution duct 465. The other end portion of duct 467 terminates ~0 in an end plate 468 through which a gas burner 469 projects.
A pipe 470 supplies gas to burners 469 and an air blower 471 supplies air for producing a combustible mixture which is dischar~ed into a hollow tubular open ended flame tube 472 wi~hin the interior of duct 467.
~ 7213~
The other end of duct 467 is closed by a supply fan 473. The function of supply fan 473 is to accelerate the pro-ducts of combustion received by duct 467 as they pass from duct 467 to duct 465 so that they are dist~ibuted to the long-itudinally spaced discharge ports 466. An access door 474 is provided in the side of duct 467.
For exhausting air from the interior of housing 420, a vertically disposed exhaust duct 480 is provided. This duct 480 protrudes through the roo 425 and downwardly, adjacent the side wall 424 which is opposite to duct 465. The open lo~er end or mouth 483 of duct 480 terminates well below the horizon-tal plane of fans 445. The upper end of exhaust duct 480 has an end plate 484 which receives a smaller cylindrical duct 486 provided with a transversely pivotally mounted flapper valve 485 which functions as a damper.
An exhaust blower 481 driven by a motor 482 has its suction side connected via condu~t 488 to the upper side o the end portion of duct 480. The blower 481 exhausts upwardly.
The setting of damper 485 determines the amount of air withdrawn via duct 480 rom the interior of housing 420.
In Figs. 12 and 13 the air is circulated as indicated by arrows 490 for drying the objects tnot shown) disposed in the interior of the housing 420.
8~
The next ernbodiment is depicted in Figs. 14 and 15, wherein an inverted U-shaped housing 520 is provided, the housing 520 having side walls 524 and a roof 525. Objects to be dried enter the housin~ 520 through an appropriate opening 527 in the front 526 of the housing 520. They then travel longitudinally through the housing 520. Disposed o~
opposite sides of the path of travel of the object through the housing 520 are a plurality of equally spaced fan assemblies 540a and 540b which are substantially identical in construction to the ~an assembly 40, except that the ~an assembly 540a rotates the fan 545a so as to draw air into it and the fan assembly 540b rotates its blade 545b in a direction to thrust air away from the an assembly 540b, as illustrated by arrows 534 in Fig. 14.
Each fa~ assembly 540a which is disposed in one side 524, has an opposing ~an assembly 540b transversely opposite to it and supported by the other side wall 5~4.
PreEerably, the an assemblies are arranged in rows as shown in Fig. 15, one row bein~ disposed above the other. In ~uch a row, the an assemblies 540a and 540b are arranged alternately. Also, the Ean asse~nblies 540a are arranged verti-cally one above the other and the an assemblies S40b are likewise arranged one above the other on a sin~le side.
Disposed between adjacent ~an assemblies 540a and 540b are heat exchangers 565 which are supplied with steam and have steam coils in substantially the same manner as de-scribed ~or the heat exchangers 65a and 65b. These heat exchangers 565 are mounted vertically to the inside ~37;~
surfaces of walls 524 and extend forwardly so as to terrninate in a position forwardly of the plane of the blades of ans 545a and 545b of their associated fan assemblies 5~0a and 540b. Thus, the air drawn in by these fans 545a is directed through the heat exchan~ers 565 which are disposed on one or both sides of the fan 545a and this air is delivered then to the fans 545b so as to be discharged into the interior of the housing 520 and against the object to be dried.
The next embodiment of the present invention is de-picted in Figs. 16a, 16b, 16c, and 17. In this embodimentr the object to be dried is subsequently cooled so that it can be handled as soon as it emerges from the drier~ Referring specifically to Fig. 16a, it is seen that the housin~ 620 is formed o a pair of vertically disposed parallel opposed side walls 624 joined along their upper edge by a roof 625 as shown in Fig. 17. Thus, like the preceding embodiments the housin~
6~0 is an inverted U-shaped member. Its ~ront end, however, is closed by an end wall 627 and one~side thereof, adjacent to the end wall 627 is open to communicate ~ith a ves~ibule, denoted ~enerally by numeral 630. The vestibule 630 is sub-stantially identical in construction to the vestibule 30 and hence no detailed description is required e~cept to state that there is an e~haust fan, denoted ~enerally by numeral 635 disposed in the roof 632 of the vestibule 630. The vestibule 630 is open at the front and receives successive objects ~not shown) which are moved by a conveyor tnot 6hown) along a path of travel, denoted by the broken line 636.
~B7~
Upon passing through the vestibule 630, the objects are fed successively sidewise into the front end o~ the hous$ng 620 and, thence, longitudinally along the path of travel de~oted by the broken line 636 as shown in Fig. 16a. Along this path of travel are a plurality o fan assemblies, denoted by the numeral 640. Each fan assembly is carried by the roof 625 so that its fan 645 is rotated about a vertical axis and is spaced below the inner surface of the roof 625. Since the fan assembly 640 is identical to the fan assembly 40, no more detailed description is provided o the same except to state that the fan assemblies 640 are ar~anged in two parallel longitudinally extending rows parallel to the side walls 624 and are respectively staggered so that the fan assembly 640 in one row is adjacent one wall 624 and the next fan assembly 640 is adjacent the other wall 624.
Between the first two fan assemklies 640 in one row, as seen in Fig. 16a, heater assembly, denoted generally by the numeral 665, is provided in the roof 625. This heater assembly 665 is a direct ired burner and includes a combustion 20 air blower 666 and a burner body 667 which receives the air and gas to produce a combustible mixture and directs the product o~ combustion downwardly through the roo~ 625 so that the flame burns within the interior of the housing 620. Addi~ional heaters 665a, 665b, and 665c are disposed in staggered relationship in the roof 625, as shown in Figs. 16a and 16b.
The burner assembly 665a is disposed between the second and third fan assembly 640 on the right side and the burner assembly 2~
665b is disposed between the 4th and 5th fan assembl~ 640 on the lef-t side. The burner assembly 665c is disposed be-tween the last two fan assemblies 640 on the right side of the oven. Each provides a combustible mixture of gas and fuel in a downwardly directed flame.
It will be observed in Fig. 17 that all fans 645 of the fan assembly 640 are disposed in a common horizontal plane spaced below the lower surface of the roof 625. A pro-tective screen 670 is disposed in spaced relationship parallel to and below the plane of ans 645, the screen 670 being sup-ported by the side walls 624, as illustrated in Fig. 17.
Cowling 668 supported by the screen 670 respectively surround the fans 645.
Connected in tandem to the discharge or rear end of the housing 6~0 is a second vestibule, denoted by the numeral 630a in Fig. 16c~ This vestibule 630a has a roof 632a supported by side walls 631à. ~t also has an exhaust fan 635a in the central portion of the roof 632a. The walls 631a are extensians of the walls 624 while the roof 632a is 2n in a common horizontal plane with the roof 632 and is at approximately the same hèight as the protective screen 670.
Any excess air, fumes, vapor and gases which accumu-late in the housing 620 are withdrawn by the exhaust fans 635 and 635a.
- 2~ -~18~Z !3~
Connected in tandem to the discharge or rear ~nd of the vestibule 630a is a cooling chamber, denoted cJenerall~
by the numeral 680. This cooling chamber 680 has side walls 681 and a roof 682. It too is an inverted U-shaped member which corresponds to the cross sectional dimensions o~ the housing 620. It too is provided with stag~ered cooling fan assemblies 74~ mounted through the roof 682. ~ach fan assembly 740 is identical to the fan assembly 40 and has a fan 745 disposed in a common horizontal plane which coincides with the common ho~i~ontal plane of the fans 645. It too has a protective screen ~not shown) and cowling 768 for the fans 745. Since there is no heating element associated with the fans 7~0, they function to quite rapidly cool the surfaces of the objects which pass therebeneath. Hence, the objects are successively discharged from the rear end 683 of the cooling chamber 680. It will be understood by those skilled in the art, that if desired, coolin~ coils in a heat exchanger, such as heat exchanger 685, may be incorporated in the roo 682 of the chamber 680, if desired. Thus t additional coolin~ of the objects may be readily pro~ided.
In the embodiments shown in Fig. 18 o~ the present invention, still another form o the present invention is depicted. This oven is or drying ~reshly painted pipes or other cylindrical members as they are passed rom one ènd to the other through the housin~, denoted ~enerally by ~he numeral 820. In more detail, the housing 820 has side walls 824 and a roof 825 and is closed at both ends by end walls which are substantially identical. Thus, only one end wall 826 is illustrated.
7Zl~
Within the central portion of the end ~,/all 826 i~
a square or rectangular central opening, over which extend3 a sheet metal plate 827, being secured to the end wall ~26 by means of screws 828. A plurality of juxtaposed circum~eren-tially disposed flexible closure plates 829 are secur~d to the plate 827 so as to protrude into the opening defined by the circular inner edge of the plate 827. The purpose of the flexible closure plates are simply to reduce the effective diameter of the opening in the plate 827 so that there is very little space between the surface of a cylindrical object such as a piece of pipe which has a Diameter D and is fed from one end of the housing 820 through to the other end of the housing 820, being supported externally at an appropriate hei~ht.
Within the housing 820 are a pair of opposed fans 845 which are disposed on opposite sides of the path of travel of the object. These fans 845 are rotated about aligned horizontal axes of their shafts 843. The fans 845 and shafts 843 form elements of the fan assemblies 840 which are identical to the fan assemblies 40 and are supported, as illustrated in Fig. 18, by the side walls 824. A heater, denoted generally by the numeral 865, includes a blower 866 and a burner 867.
The burner 867 is mounted in one of the end walls 826, as illustrated in Fig. 18, and directs the mixture of either gas or oil and a~r into the interior of the housing 820 in essentially a hori~ontal path below the roof 825 and above .~ !37Z~3~
the path of travel of the object. Thus, the ~ans ~5 draw the heated products of combustion in pairs as ilLustr~ted by the arrows 868 in Fig. 18 and direct this heated gas against opposite sides OL the object, simultaneously.
In the embodiments hereinbefore described, it is important -that the fans 45, 145, 245, 345, 445, 545, 645, 745 and 845 be spaced from their associated ~all or roof by at least about two feet and not more than about six feet. By so positioning the fans, there is very little vacuum drawn on the back sides Of the fans in delivering a very high velocity of air. The hea-~ers which are disposed in various rela-tionships to the fans are all arranged so that the air is heated imm~diately prior ~o being delivered to the back sides of the fans. Further-more~ the return velocity of the air where it, at times,is again heated by the heating elements, is quite low~ thereby enabling substantial heat transfer before the air is again delivered by the fans at high velocity. Since the velocity of the air is low, on return, there is little trash picked up from the Eloor. The heat can be fed into the oven at substantially any place and will be quite readily disseminated throu~hout the oven. Therefore, the oven is quite uniformly heated.
~Ieat introduced, however, should be generally transverse to the path o~ travel of the propeller or fan blades.
In the fan assembly 40, the inner bearing, which permits both rotational movement and a~ial movement, is cooled by the flow of air in the casing 41 and the shaft is, likewise, 3L~L1 37z~
cooled. The air is introduced from the exterior down past the shaft and past the inner bearing, due to the low prcssuxc or slight vacuum generated on the back side of the fans.
Since the air is delivered quite rapidly and at hi~h velocity of the surfaces to be dried, there is little need for heating the oven beyond about 900F to achieve very rapid drying of the surfaces of the objects.
Thus, aluminized steel plates may be utilized for the panels from which the housings are made. In the event that temperatures from about 900F to about 1800F are contemplated for the interior of the oven, it is recommended that stainless steel be used for the panels and that Incone ~ blades be employed for the fans.
As seen in Figs. 19 and 20, a modified form of fan assembly 940 which is particularly suited to low temperature ovens, i.e. ovens which do not heat above about 350F is shown.
The fan assembly includes a hollow tubular sleeve or casing 941 which is rectangular in cross-section~ The sleeve 941 is preerably made up of opposed channel members 941a, 941b, the edges of which have opposed abutting 1anges 942 bolted together by spaced bolts and nuts 944.
A motor 958 is secured in the inner end portion of the sleeve 941 and has an outwardly protruding motor shaft 943 protruding inwardly; perp~ndicularly to the wall 924. The end of shaft 943 is provided with a rotary or bladed propeller 945 which includes a collar 946 secured to a hub 947 and blades 948 which radiate from the hub 947. In front of the fan 945 7~1 is a protective screen 970 supported by the ~,~alls o~ thc housing 920.
The outer end of sleeve 941 protrudes throucl~ a side wall or roo~ wall 92~ and is supported in place by anqle iron brackets 952 and 953. Since the outer end of sleeve ~1 is open to the ambient air, the rotation of the fan 945 by motor 958 will generate a draft through the sleeve 343, t~rough the motor 958 and into the interior of the housing ~20. This flo~
of air through motor 958 keeps the motor 958 cool.
A feature o~ the invention is the ability to provide temperature zones within a single oven. This is accomplished by using independent temperature controls on the steam coils or the gas or oil burner~ The benefit of beina able to zone the oven is that the most efficient rate Gf heat transfer for a specific portion of the cure cycle can be provided.
In addition to zoning the temperature, the velocity at which the air is impinged on the processed part or object can also be zoned by varying the RPM's of the fans throughout the length of the oven.
I have found from actual tests that the heat transfer o the ovens discussed above are from 5 to 10 times ~reater or faster than the heat transfer o~ ovens with only limited circulation. Thus, unusually fast drying of surfaces of objects is achieved. Through -the high velocity of air delivered by the fans against the objects, the boundary layer is minimized and the solvent of paints is quite rapidly removed from the paint so that the painted surfaces are quite rapidly dried.
It will be understood that while I have disclosed the use of steam coils and the use of gas or oil burners, 7Z~
electric heating coils may be used in place of the steam colls, if desired and any combination of steam, electric, oiL or gas heating may be employed, if desired.
It will be obvious to those skilled in the art that many variations may be made in the embodiments here chosen for ~he purpose of illustrating the present invention and full result may be had to the doctrine of equivalents without departing from the scope of the present invention as defined by the appended claims.
~87~
electric heating coils may be used in place of the steam coi.ls, if desired and any combination of steam, electric, oiL or gas heating may be employed, if desired.
It will be obvious to those skilled in the art that many variations may be made in the embodiments here chosen for the purpose of illustrating the present invention and full result may be had to the doctrine of equivalents without departing from the scope of the present invention as defined by the appended claims.
- ~8 -
Claims (2)
1. A high turbulence heat transfer oven for drying objects comprising:
(a) a housing having a continuous common essentially open interior through which objects to be dried are passed along an open path of travel;
(b) fan means disposed at spaced intervals along said path and in said common open interior of said housing for cooperating in producing a circulation of air in said interior from the front side of each of said fan means toward said objects and thence around to the back sides of said fan means, each fan means directing air against said objects;
(c) spaced heating means along said path of travel for heating only a portion of the air as it is returned to the back sides of each of said fan means for inter-mixing with the air in said essentially open interior and (d) control means for individually, respectively controlling the amount of heat delivered by said heating means.
(a) a housing having a continuous common essentially open interior through which objects to be dried are passed along an open path of travel;
(b) fan means disposed at spaced intervals along said path and in said common open interior of said housing for cooperating in producing a circulation of air in said interior from the front side of each of said fan means toward said objects and thence around to the back sides of said fan means, each fan means directing air against said objects;
(c) spaced heating means along said path of travel for heating only a portion of the air as it is returned to the back sides of each of said fan means for inter-mixing with the air in said essentially open interior and (d) control means for individually, respectively controlling the amount of heat delivered by said heating means.
2. A high turbulence oven for drying objects com-prising:
(a) a housing having a common essentially open interior through which objects to be dried are passed along a path of travel;
(b) fan means disposed in said open interior at spaced intervals along said path for cooperating in producing a circulation of air in said interior from the front side of each of said fans toward said objects and thence around to the back sides of said fan means, each for means directing air against said objects;
(c) spaced heating means along said path of travel for heating only a portion of the air as it is returned to the back sides of each of said fan means for inter-mixing with the air in said essentially open interior; and (d) control means for individually, respectively controlling the speed of the fan means.
(a) a housing having a common essentially open interior through which objects to be dried are passed along a path of travel;
(b) fan means disposed in said open interior at spaced intervals along said path for cooperating in producing a circulation of air in said interior from the front side of each of said fans toward said objects and thence around to the back sides of said fan means, each for means directing air against said objects;
(c) spaced heating means along said path of travel for heating only a portion of the air as it is returned to the back sides of each of said fan means for inter-mixing with the air in said essentially open interior; and (d) control means for individually, respectively controlling the speed of the fan means.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/916,214 US4235023A (en) | 1978-06-16 | 1978-06-16 | High heat transfer oven |
| CA000337590A CA1141534A (en) | 1978-06-16 | 1979-10-15 | High turbulence heat transfer oven |
| US06/282,531 US4426792A (en) | 1978-06-16 | 1981-07-13 | High turbulance heat transfer oven |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000418716A Division CA1160830A (en) | 1978-06-16 | 1982-12-29 | High turbulence heat transfer oven |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1187281A true CA1187281A (en) | 1985-05-21 |
Family
ID=27166440
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000444252A Expired CA1187281A (en) | 1978-06-16 | 1983-12-23 | High turbulence heat transfer oven |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1187281A (en) |
-
1983
- 1983-12-23 CA CA000444252A patent/CA1187281A/en not_active Expired
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| MKEX | Expiry |