US2300782A - Heat exchange coil - Google Patents

Description

Nov. 3, 1942 CIE. GoLLMl-:R

HEAT EXCHANGE COIL Filed ot. si, 1938 Patented Nov. 3, 1942 USNlTED STATES HEAT EXCHANGE COIL Carl E. Gollmer, Hoopeston, assignor .tovFood Machinery Corporation, San Jose, Calif., a corporation of Delaware 3 Claims.

This invention relates to heat exchange apparatus and, more particularly, to coil or piping systems adapted to accommodate and circulate steam or other heating medium for the purpose of heating or cooking the contents -of a vat, kettle, or the like.A

In the cooking of fruit and vegetable pulps, prior to the canning or preserving of the same, there is frequently used aY large vat or tank containing a set of coiled tubes through which live steam is passed, the heat furnished by the same resulting in the heating and cooking of the pulp contained within the tank. There are numerous desiderata relative to these steam coils, among which are efficient transfer and utilization of heat, uniform heating and avoidance of local overheating, rapid and complete drainage of con clensate, simplicity of design with a minimum of fittings inside the vat, and so on.

t is an object of the present invention to provide a construction and arrangement of heat exchange coils which is simple, inexpensive to construct and install and highly eicient in operation.

Another object is to provide a steam coil for heating the contents of a vat, and a manner of operating the same, whereby highly efficient utilization of the heat is obtained accompanied by uniform distribution of the same so that the contents of the vat is heatedquickly and evenly and localized overheating is avoided.

Another object is to provide a steam coil from which condensate will drain rapidly and substantially completely with little or no tendency to back up in the coil.

A further objectv of the invention is to provide a steam coil wherein there will be minimum steam expansion, high velocity of the steam, and rapid discharge of the condensate, thus insuring a maximum of heat transfer per square foot of coil surface;

Another object of the present` invention is to provide a steam supply header for a plurality of heat exchange coils whereby steam from a single source of supply may be admitted to each of said coils at an equal pressure and velocity and with a minimum of steam expansion, skin friction and turbulence.

A still further object of the invention is to provide a novel discharge header for a plurality of coils whereby condensate may be discharged separately from each coil and whereby pressure differential in the coils will have no influence on the individual coils. n

With these and other objects in View, the invention consists in the construction, operation and novel combination and arrangement of parts described in detail in the following description, illustrated in the accompanying drawing,- and particularly pointed out in the appended claims, it beingV understood, of course, that various changes inthe form, proportions and vminor details and arrangements of parts may vbe resorted to, within the scope of the claims, without departing from the spirit `of the invention or sacrificing any of the advantages thereof.

In the drawing:

Fig. l is a vertical section through a tank or. vat showing a set of coils, constituting an embodiment of the present invention, inI place therein, the coils being shown in elevation.

Fig. 2 is averticalsectional view through the coils and headers, taken approximately on the line 2 2 of Fig. 3.

Fig. 3 is a top plan view of the coils vof Figs.

1 and 2. i

Referring to Fig. 1 of the drawing, there has been shown a vat or vessel 4 which may be constructed of Wood, metal or any other suitable material. The vessel 4 is provided with a bottom 5 preferably sloping gently downwardly to a centrally disposed outlett, normally closed by a suitableplug or valve l, and communicating With an outlet or discharge pipe 8. It is understood that the Vessel 4 isl adapted to be lled with any desired fluid material, such as, a vegetable pulp, which may be discharged through vthe outlet and dischargepipe 8 upon completion ofthe heating or cooking operation.

The vat 4 is preferably circular is cross-section although it may,.of course, assume any cross# sectional configuration desired, and the bottom 5 is provided at a point adjacent its peripheryv with an opening adapted to receive a nipple ,9,

secured to a steam supply header or riser I 0 in any convenient manner. The nipple 9 extends through the opening and protrudes rbelow the` ATENT OFFICE At its upper end the header I is surmounted by a fitting or distributor I5 which may best be described as a double reversed elbow having one section I8 thereof faced in one direction and the other section I'I thereof faced in the opposite direction. This fitting may be integral with the header I0 or, of course, may be attached thereto in screw threaded manner or in any other suitable or desired fashion.

The distributor elbow portions I6 and I1 are provided with openings IISa and IIa, respectively, for attachment of the free ends of heat transfer coils I8 and I9 by means of welding, shrinking or the like. The openings I6a and I'Ia of the distributor I-5 are both positioned at the same level and are furthermore equally spaced from the vertical axis of the supply header I0. In this way the steam inlet portions of the coils I8 and I9 are located in such a manner with respect to the vertical portion Illa of the steam supply header as to eliminate variations in steam pressure and velocity therein.

Y 'I'he arrangement and construction of the steaml supply header I0 prevent heat losses due to expansion of steam which would otherwise materially effect the eihciency of the device.

The distributor portion I5 includes further a downwardly converging steam dividing section I5a for facilitating admission of steam from the header Ill to the heat exchange coils without any appreciable amount of skin friction and turbulence.

The heat transfer coils of the present invention preferably take the rform of a pair of coiled and nested tubes I8 and I9. In the illustrated embodiment, each of these coils is shown to consist of 21/2 turns or convolutions, which has been found to supply adequate heating surface in most instances. It will be understood, of course, that any number of convolutions may be used to suit thev particular requirements in each case. The innermost tube I8 is suitably connected in the elbow section I6 and from there describes 21/2 convolutions in a counterclockwise direction, with a considerable drop in elevation of each, and terminates in suitable connection with one of the elbow sections 2| of another reversed double elbow fitting 20, similar to the double elbow I 5, and located at a point substantially diametrically opposite from the latter. The outer coil I 9 is suitably connected in the elbow section I'I, and after making 21/2` convolutions in a clockwise direction with substantial drop in the elevation of each, terminates in suitable connection with the elbow section 22 of the fitting 20 which faces in a direction opposite to that of the section 2I The `double elbow fitting 20 forms a part of or is attached to a discharge header 23. More specifically the discharge header 23 includes a portion 24 extendingv through a suitable opening in the bottom 5 of the vat 4 and is clamped therein through the medium. of annular flange 25 and nutv 26 cooperating with a suitably sore7 threaded portion at the end of the section 24. Washers 25a and 25a adjacent the flange 25 and nut 25 respectively may be provided to establish a fluid tight seal between the discharge header 23 and the bottom 5 of the vessel 4. The discharge header is divided internally into two sections by means of a diametrically disposed partition 2'I which bisects the double elbow tting 20 land divides the header 23 into two approximately equal halves 28 and 29. It will be noted that the inner coil I8 communicates with the manner.

discharge header` section 29 through the elbow 2|, and that the outer coil I9 communicates with the other header section 28 through the elbow 22. It will be understood that the partition 2I is a solid one, completely bisecting the tting 20 and the header 23 into two separate and noncommunicating portions so that there may be no communication between the respective coils I8 and I9 at their discharge ends.

In the embodiment shown, the lower end of the discharge header 23 is closed as at 30, and the opposite sides of the header taper down to the closed end of portion 30. At the tapered areas there are provided internally screw threaded openings 3I and 32, respectively, which are adapted to receive the externally screw threaded ends of discharge pipes 33 and 34 in known It will be obvious that the portion of the header or passageway 28 communicates with the discharge pipe 33 while the opposite passage 29 communicates with the discharge pipe 34. Each of the discharge pipes is provided with conventional strainer 35, steam trap 36 and control valve 3'I for a purpose which will be manifest to those skilled in the art. The discharge pipes 33 and 34 may lead ultimately to the boiler, to a water storage tank or to any other desirable place for disposal of the water of condensation.

In operation, a suitable quantity of material to be heated or cooked is run into the tank 4, the valve 'I, of course, being closed to hold the material in the tank. The pipe I3 being in communication with a suitable source of steam, the valve I4 is manipulated to allow the passage of steam through the pipe I3 and up into the supply header I0. At the top of the header, in the double reversed elbow I5, the flow of steam will be split into two portions, one entering the coil I8 and traveling in a counter-clockwise ldirection as indicated by the arrow in Fig. 3, and the other entering the coil I9 and flowing in a clockwise direction as indicated by the arrow. One of the main features of the invention is the arrangement whereby in a set of nested concentric coils the steam travels in opposite directions in each. The inlet header I0 and tting I5 distribute the steam equally to coils I8 and I9 with very little drop in pressure, and at a very high velocity, the arrangement being so constructed as to cause very little skin friction in dividing the steam.

After flowing in a counterclockwise direction through the 21/2 convolutions of coil I8, the water of condensation and any remaining uncondensed steam discharge into the elbow 2| of f1tting 20 and flow downwardly through the passageway 29 of the discharge header 23 and ultimately through the discharge pipe 34 to a suitable destination. In like manner, the steam travels through steam coil I9, flowing in a clockwise direction and discharging through the elbow 22, passage 28 and discharge pipe 33.

Due to the difference in their respective volumes, there will generally be a differential in the pressure in each of the coils I8 and I9. Were i they to discharge through a single undivided passageway or header, this pressure differential might tend to cause condensate to back up in the coil having the lower pressure. Manifestly, this condition is obviated by providing the discharge header 23 with its central partition 21 so that the discharge passageways 28 and 29 for the respective coils are entirely separate and distinct so that each may discharge properly Without being at all influenced by the pressure in the other. By thus having the two coils discharge through a single header, the necessity for a plurality of openings through the bottom of the tank is obviated, thus simplifying construction and installation to a considerable degree.

It will be seen that the pitch or inclination of each of the tubes constituting the coils I8 and I9 is considerable so that the ow of steam through the tubes may be at high Velocity and drainage of condensate will be rapid and substantially complete. Thus, there is little likelihood of any substantial amount of condensate remaining in the coils to interfere with eiicient utilization of the heat.

It also will be noted that there is required only one steam supply header and thus, only one opening in the bottom of the tank for the same. This header supplies steam at exactly the same temperature and pressure to each of the coils, and since the steam travels in opposite directions at the same time in the respective coils, there is more even distribution of the heat to the contents of the vessel throughout the entire surface area of the coils.

I claim:

1. A heat exchange apparatus comprising a pair of oppositely convoluted steam conducting coils, an inlet header for supplying steam to said coils, said inlet header comprising a tubular supply conduit having an end wall closing one end thereof and being provided with a pair of oppositely directed laterally disposed openings adjacent said closed end, said coils being respectively connected with said openings, and an inwardly protruding deflecting ridge formed on the inner face of said end wall in line with the axis of said supply conduit to evenly divide and direct steam flowing through said conduit to said openings.

2. A heat exchange apparatus comprising a steam supply header made up of a tubular supply conduit having a generally S-shaped hollow discharge fitting centrally mounted on one end thereof, said tting being provided with a pair of oppositely directed openings at its ends facing laterally with respect to said supply conduit, a pair of oppositely convoluted steam conducting coils respectively connected with said openings, and an inwardly protruding deflecting ridge formed on the inside of said tting in line with the axis of said supply conduit to evenly divide and direct steam flowing through said conduit to said coils through said openings.

3. In heat exchange apparatus, a steam supply header comprising a tubular supply conduit having a distributor portion at its upper end provided with a pair of openings positioned at the same levell and equidistant with respect to the vertical axis of said header, a pair of nested oppositely convoluted helical tubular coils having their inlet ends respectively connected with said openings, and av downwardly converging steam dividing protuberance in said distributor portion in line with the axis of said supply conduit to evenly divide and direct steam iiowing upwardly in said conduit to said openings.

v CARL E. GOLLMER.

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