US2420824A - Fluid removal device for drying drums - Google Patents

Description

y 1947- L. HORNBOSTEL ET AL 2,420,824

FLUID REMOVAL DEVICE FOR DRYING DRUMS Filed April 1, 1944 2 Sheets$heet l lZa.

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y 1947- L. HORNBOSTEL ET AL 2,420,824

FLUID REMOVAL DEVICE FOR DRYING DRUMS Filed April 1, 1944 2 Sheets-Sheet 2 40140 flaeusvsrnc @Wdwhv E GOOoWML/g.

Patented May 20, 1947 FLUID REMOVAL DEVICE FOR DRYING DRUMS Lloyd Hornbostel and John E. Goodwillie, Beloit, Wis., assig'nors to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Application April 1, 1944, Serial No. 529,210

7 Claims. 1

The present invention relates to fluid removing devices for cylinders, and it is particularly directed to a device that is adapted to eflectively remove fluid from the interior of a Yankee drier drum. in a paper making machine.

In the drying of certain types or grades of paper in a paper making machine, it has been found that in the paper sheet leaving the Yankee drier drum that is equipped with the usual type of liquid removal devices, there are different degrees of moisture in the sheets, or variations of the moisture or the dried sheet may have moist areas. This condition is not serious in the average paper sheet, but it has proven critical in special types of paper that require extremely accu rate drying entirely across the length of the drum, especially when the drum is running at high speed. Investigations have disclosed that this unevenness of drying is due to the fact that the clippers or shoes which are usually employed for picking up or scooping the water in the drum are of relatively small dimensions as compared to the length of the drum and that these shoes are disposed in contact against the inside surface of the drum and are usually secured directly thereto. As a result of this prior arrangement the heating medium, such as steam, does not pass between the contacting surfaces of the drum and clippers and therefore is not fully effective upon the continuous portions of the drum surface with which the paper sheet is engaged. Also when the drum is rotated at high speed the liquid forms a film on the inside surface of the drum and is not picked up except at the location of the relatively narrow clippers or shoes. Consequently the superficial areas of the outer surface of the drum at the location of the shoes were not heated to the same extent as were the remaining areas of the drying surface on the drum, and the film created at high speeds prevented the steam coming into direct contact with the inner drum surface. The present invention aims to overcome this serious condition by providing an effectively operating liquid removal device having dippers or shoes that are constructed and arranged to permit the heating medium to be effective directly upon the entire interior surface of the drum.

It is one of the principal objects of this invention to simplify the construction of a fluid removing device such as contemplated herein, and to improve the efficiency, operation and dependability of such fluid removal device.

Also it is a principal object to provide a liquid removing device that will effectively overcome the objectionable condition above stated especially as applied to the Yankee drier drum of a paper making machine.

It is also one of the principal objects of this invention to provide a device that is arranged to remove the fluid across substantially the entire inner surface of the cylinder when the cylinder is rotating at relatively slow speeds and the fluid thereby tends to form in a puddle in the bottom or lower segment of the cylinder. This device also is effective to remove a film of liquid that will form on or cling to-the inner surface of the cylinder as a result of the high rotational speed of the Yankee drum when drying special types of paper.

Another object is to provide a fluid removing device that will not interfere with the heating of the entire surface of the drier drum, so that it will thereby avoid the creation of insufficiently heated spots on the drum and the resultant uneven drying of the paper sheet carried by the drum.

A further object hereof resides in providing a fluid removal device that is supported by the heads or ends of the drum and which is suspended in spaced relation to the inner surface of the cylindrical wall of the drum, to permit the steam or other heating medium to circulate or pass beneath the device in intimate relation with the wall of the drum to heat the latter through out its circumference.

Another object of this invention is to provide a fluid pick-up dipper or shoe assembly for a fluid removal device that is effective to remove the condensate liquid regardless of whether the drier drum is rotating at fast or slow speed. This dipper or shoe is constructed so as to function as a scoop when the drier. drum is revolving slowly, and it acts as a sweeping device when the drier is running at a speed that is fast enough to create a fllm on the inner surface of the drum.

Still another object is to provide a fluid removal device with a pick-up dipper or shoe that has a restricted ingress area entrance space that is less than the area of the drain pipe that con veys the liquid out of the drum, whereby the fluid is retained in the drain pipe and prevented from back-flow or retrograde movement after it has passed the entrance portion of the shoe. I

In other words, this fluid removal device which constitutes the present invention is of a selfthrottling character.

It is a further object of the invention to provide means on the pick-up dipper or shoe of a fluid removal device to define a tapered throat and a channel next to the drum surface for directing the liquid to the ingress portion of the removal device and for allowing the heated vapor to travel between the dipper and the drum.

Additional objects, aims and advantages of the invention contemplated herein will be apparent to persons skilled in the artafter the construction and operation of the fluid removal device is understood from the within description. It is preferred to accomplish the numerous objects of this invention and to practice the same in substantially the manner hereinafter fully described and as more particularly pointed out in the appended claims. Reference is now made to the accompanying drawings for a better understanding of this invention.

Figure 1 is a longitudinal elevation of a Yankee dried drum fo a paper making machine, with the cylindrical wall broken away and disclosing the instrumentalities of the present invention installed therein;

Figure 2 is a transverse vertical section along the plane of line II-II of Figure 1 looking in the direction of the arrows and drawn to an enlarged scale Figure 3 is a top plan of a pick-up shoe or dipper constituting a portion of the present invention;

Figure 4 is an enlarged transverse vertical section taken along the plane of line IV-IV on Figure 3; and

Figure 5 is an enlarged front elevation of an end portion of the fluid pick-up shoe or dipper looking toward the leading edge thereof with the adjacent portion of the drum in section.

The drawings are to be understood as being more or less of a schematic character for the purpose of disclosing a typical or preferred form of the. improvement contemplated herein.

The drum shown herein is preferably'a Yankee drier drum of a paper making machine that comprises a hollow cylindrical wall 10, to the ends of which concavo-convex heads II are secured in any suitable manner to provide end walls having convex inner surfaces. Openings are made in these heads H to receive the axle or shaft of the drum which shaft comprises axially aligned hollow or tubular members I2 and I3, the proximate .ends of which abut a dividing plate N that has a thickened margin or rim portion [5. Annular flanges l6 and I! are formed on the inner ends of the tubular members l2 and I3, respectively, that are drawn towards each other and clamped to the rim portion l5 of the dividing plate I4 by bolts that pass through said flanges and said dividing plate.

Radially disposed bores I8 are. drilled through the thickened rim portion l5 of the dividing plate l4 to establish communication between the interior of the shaft member I3 and the interior of the drum cylinder [0, and steam nozzles 19 are threaded into these bores l8 for discharging steam into the drum from the tubular shaft member [3. The outer ends of the tubular shaft members l2 and 13 are suitably anchored to heads I l and project outside the same to provide hollow trunnions [2a and I3a, respectively, for journaling the drier drum for rotation in bearings 20 and 2|, respectively on pedestals 22.

The trunnion l2a has a liquid removing pipe 23 in it and a seal ring or other sealing device (not shown) is interposed between the trunnion and the pipe to seal the clearance between these parts and prevent escape of the heating vapor or steam therebetween. This arrangement also permits the pipe 23 to remain'stationary while the trunnion In is rotating with the drum. The outer end of pipe 23 leads into a condenser tank 24 from which liquid is withdrawn through a pipe 25 b a pump 26 or other fluid displacement device that is actuated by a prime mover such as an electric motor 21. The inner end of pipe 23 is in communication with the interior of the hollow shaft member I 2 to receive the liquid that is discharged thereinto by the drain pipes 28 of liquid removal devices.

The drain pipes 28 are formed with intermediate expansion loops 29 and have their end portions 30 inserted radially through suitable holes in diametrically opposite segments of tubular shaft member I2 to communicate with the interior thereof and they are held in place on said shaft member by seal couplings 3| so that said drain pipes will travel with the shaft and drumduring rotative movement thereof. The other end portions of the pipes 28 are curved as at 32 in the direction of rotation of the drum and near the inner surface of the drum they are provided with oppositely disposed branches 33 that extend laterally away from the pipes toward the heads ll of the drum.

The ends of the drain pipe branches 33 are fitted into holes 34 in the adjacent segments of elongated tubes 35 of relatively larg diameter that 'extend the length of the drum and preferably constitute the header portions of the fiuid removing shoes or dipper assemblies. These header tubes 35 are close to but they are in non-contacting, slightly spaced relation to the adjacent inside surface of the drum ID as clearly shown in Figures 2, 4 and 5, and branches 33 are secured in the holes 34 of the headers by welding, brazing, or any other suitable manner to effect a rigid assembly therewith.

The outer portions of one of these fluid pickup shoes or dippers, which is shown in detail in Figures 3, 4 and 5, will now be described. The shoe or dipper is mounted upon and carried by the heads I I of the drum by means of a bracket and a fitting device. The bracket comprises a plate 36 having a concave outer face to conform with the curvature and fit against the inner surface of the head H of the drum, and it is brazed or otherwise secured thereto. An inwardly extending plate 31 back of header 35 has one of its end edges abutting and welded to the plate 36 so that it projects inward therefrom. An other plate 38 of substantially the same length as plate 31 has its adjacent end edge welded to the lower portion of the concave plate 36 and has its leading edge engaged with and secured, preferably by welding, to the lower margin of the longitudinal plate 31. This arrangement provides a rigid bracket that has a somewhat box shape.

The fitting device comprises a longitudinal back plate 39 disposed fiat against the front face of the plate 31 of the bracket to which it is secured by bolts 40. A plurality of relatively tall fins 4| project laterally and forwardly from the back plate 39 to extend over and around portions of the circumference of the header tube 35 to which they are suitably attached with their leading edges projecting beyond or in front of the header. 35. The back plate 39 and fins 4| of this assembly provide a rigid support for the dipper or shoe and suspend it on the heads I! in non-contacting relation to the inner surface of the drum. A plurality of shorter fins 42 project forwardly from the header 35 on the circumference thereof between the groups of tall fins 4| at the ends of the header 35. The lower edges ofthe fins 4| and 42 that are nearest the inner surface oi. the drum in are arcuately curved and have a scoop-shapedconcavo-convex lip 43 secured to them.- Thus the intermediate portion of the header is reinforced.

It will be seen by reference to Figure 4 that thelip 43 constitutes a forwardly extending vane on the lower portion of the tubular header'35 and, with the surface of the drum, defines a tapered throat a: leading to a channel 1 that is coextensive with the length of the drum beneath the dipper assembly.' At the juncture of the lip 43 with the tubular header 35 the latter has a longitudinally disposed elongated slot 44 that extends the entire length of said header. This slot 44 is in the lower segment of the tube forming header and near the drum to admit the condensate fluid from the throat a: into the interior of the header across the length of the drum. The leadingedge of the slot 44 is at or adjacent the trailing edge of lip 43, while. the other edge of said slot is in the segment of the header that is nearest to the inner surface of the drier drum. Conceivably, in lieu of the full-length slot 44, the opening into the tubular header 35 may be a plurality of adjacently disposed slots, or a plurality of round apertures that are bored into the header.

For the purpose of effecting a controlof the fluid after it has entered the dipper assembly, suitable throttling means are provided that comprise a base plate 45 secured to the segment of the header 35 that is nearest the drum and arranged tangent to the circumference of the header at the rear or trailing edge of the slot 44. The leading edge of base plate 45 is forward of the juncture between the lip 43 and the header, and said leading edge is separated from said lip 43 by a spacer strip 46 having a plurality of apertures 47 therethrough for effecting the passage of the fluid into the elongated chamber 48 that is provided between the plate 45 and the lip 43. The fluid is admitted to said chamber 48 through apertures 41 and it then enters the header 35 through the elongated slot 44. The apertures 4'! are of such dimension that the total area thereof is below or less than the area of the drain pipe 32 that communicates with the header 35 of the fluid pick-up shoe or dipper. As shown in the radial relation to the shaft or axle of the drum,

drawing, the fluid flow passage area. of the opening 44, the header 35, and the bore of hollow member l2 are also of greater area than the total area of apertures 41. Accordingly all fluid passages between inlet apertures 41 and the exterior of the drum are of greater area than the total area of apertures 41. This construction provides a tangently disposed ingress or intake nozzle for the device, and also constitutes a self-throttling arrangement that prevents retrograde movement or back-flow of the liquid into the drier drum after it has been picked up by the fluid removal device. The ingress nozzle is spaced from the inside surface of the drum and provides a passage way y the length of the drum to allow steam to pass therethrough toheat the surface continuously.

The live steam or heating medium is introduced into the drum through a conduit 49 from a suitable source, and a Venturi device 50 is interposed in this conduit adjacent to the trunnion l3a of the drum. The end of the conduit within the trunnion [3a is in sealed relation with respect to said trunnion to prevent escape of steam. The

and after the fluid passes through the drain pipes 28 it is discharged through the ends of said pipes into the hollow axle section l2 from which it is conducted through pipe 23 to the condenser 24. It will be seen that the entire structure of the shoes or dippers are maintained in spaced relation to the inner surface of the cylindrical wall 10 of the drum so that there will be no interference withthe heating of the drum surface by the steam or other heating medium with which the drum is charged and consequently the outer surface of said drum will be maintained at a uniform drying temperature throughout its entire surface. The ingress or intake nozzle portions of the dippers are close enough to the drum to scoop up the film of liquid that is created on the adjacent drum surface during high rotational speed, and said ingress portions will also enter a puddle of liquid that accumulates in the bottom of the drum when the latter is rotating at a slow speed.

We claim as follows:

1. In combination with a rotatable cylinder having end heads and means for introducing a heating fluid into the cylinder, a fluid-removing device in said cylinder extending the length of the cylinder, means carried by said end heads supporting said device in non-contacting closely spaced relation to the inner surface of the cylinder, said device defining an inlet passage facing in the direction of rotation of the cylinder, a lip on said device coacting with the inner surface of the cylinder to provide a throat for directing fluid toward the inlet passage, and said inlet passage having a wall in closely spaced relation to the inner surface of the cylinder for coacting therewith to define a passageway accommodating flow of fluid between the device and the cylinder.

2. In combination with a steam-heated rotatable cylinder wherein steam that is introduced thereinto is adapted to condense and form a puddle of liquid at the bottom thereof at low rotational speeds of the cylinder or form a. liquid film on the inner surface of the cylinder at high rotational speeds, a liquid-removing device comprising a pipe in said cylinder extending along with the inner surface of the cylinder to direct fluid toward the inlet, and a drain tube connecting said pipe for drainage of liquid out of the cylinder whereby said lip is effective to direct liquid from a puddle or a film in excess of the width of the passageway into the pipe while said passageway accommodates passage of thin film of liquid between the pipe'and cylinder.

3. A dipper for removing condensate from a rotatable steam-charged cylinder which comprises an elongated pipe for extending along the length of said cylinder. said pipe having a slot along its length, a tangential ingress nozzle secured on said pipe for directing condensate through the slot thereof, and an apertured plate in said nozzle limiting the effective opening of the nozzle to throttle flow of condensate into the pipe.

4. A dipper for removing condensate from a rotatable steam charged cylinder which comprises a hollow header extending along the length of said cylinder and having a slot along the length thereof, and a vane secured on said header adjacent one edge of said slot adapted to cooperate with the inner surface of the cylinder to direct fluid toward said slot, and a plate-like member secured on said header adjacent the other edge of said slot and adapted to lie intermediate said vane and the inner surface of the cylinder, said plate-like member cooperating with said vane to define an ingress nozzle for said slot.

5. .A dipper assembly for removing condensate liquid from the drier drum of a paper making machine, comprising a hollow header having a slot along the length thereof; an ingress nozzle secured on said header along the length thereof communicating. with said header through the slot to provide a tangential inlet for the header; and a lip projecting in front of the inlet portion of said nozzle for directing condensate liquid to the nozzle from the inner surface of the drier drum, and supports for holding said assembly in non-contacting relation to the inner surface of the drum for effecting passage of the steam therebetween to heat the cylinder adjacent said dipper assembly.

6. In combination with the rotatable drier drum of a paper making machine that is charged with a heating vapor, a liquid removing device therefor carried by the end Walls of the drum and comprising a hollow header having a longitudinal slot, said header extending the length of the drum in non-contacting relation to the inner surface thereof to effect passage of the heating vapor therebetween; a tangential ingress nozzle communicating with said header throughout the length of said slot thereof; a lip projecting in front of said nozzle for directing condensate liquid from the inner surface of said drum to the intake-portion of said nozzle; and a drain pipe communicating at one end with said header to receive the liquid therefrom. the other end of said pipe being disposed to discharge the liquid outside the drum.

7. In combination with the rotatable drier drum of a paper making machine that is charged with a heating vapor, a liquid removing device therefor comprising an elongated dipper having an inlet passage extending the length of the drum; means for suspending said dipper in said drum with one longitudinal passage defining wall thereof disposed adjacent to but spaced from the inner surface of said drum, thereby defining a flow path for heating yapor intermediate said dipper and the adjacent surface of the drum; a vane projecting frogn the other longitudinal passage defining wall m a circumferential direction with respect to the drum and cooperating with the adjacent drum surface to provide a throat between said vane and the wall of the drum for directing fluid toward said inlet passage, and means for conveyin the liquid from the dipper and discharging the liquid outside the drum.

LLOYD HORN'BOSTEL.

JOHN E. GOODWILLIE.

' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 543,051 Phillips 1 July 23, 1895 784,821 White Mar, 14, 1905 1,670,113 Harrison May 15, 1928 1,108,077 Kilberry Aug. 18, 1914 1,181,099 Coppage Apr. 25, 1916 1,555,624 Barrus Sept. 29, 1925 1,919,416 Cram July 25, 1933 1,643,973 Woodsome Oct. 4, 1927 1,662,095 Woodsome Mar. 13, 1928 2,328,321 Berry Aug. 31, 1943 FOREIGN PATENTS Number Country Date 370,621 Great Britain Apr. 14, 1932

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