US2538270A - Film processor - Google Patents

Description

1951 v. E. PRATT ETAL FILM PROCESSOR 2 Sheets-Sheet 1 Filed Dec. 25, 1947 INVENTORS VERNEU/ E. PRH GEORGE E GRAY UWMJM IQTTOP/VEYS Jan. 16, 1951 v. E. PRATT ET AL FILM PROCESSOR 2 Sheets-Sheet 2 Filed Dec. 25, 1947 III'IIIIIIIIIIIIIIIIII'llIIIIIIIIIHIIIIIIIII'll!- INVENTORS VEAWEl/R E. PRATT 650265 E 626V Um Mafia.

4 TTOIP/VE YS Patented Jan. 16, 1951 FILM rnocassoa Verneur E. Pratt and George F. -Gray, Norwalk, Conn.

Application December 23, 1947, Serial No. 793,360-

This invention relates to improvements in film processors, and has for an object the provision of a processor for film or other light-sensitive coated strips adapted to automatically develop, fix, wash, and dry the strips and roll them up again ready for use. Such a machine makes it unnecessary to have to employ a skilled technician to operate the machine.

Another object of the invention is the provision in a film processor of an array of U-shaped tubes which constitute the tanks for containing the processing fluids and through which the exposed light-sensitive strip is passed.

Yet another object. of the invention is the provision in a film processor of the character described, and means for circulating the processing fluid in the individual ll -shaped tubes, said means including a pump the outlet of which delivers the fluid to a manifold adjacent to the inlet end of one leg of the U-shaped tube, and the provision of an overflow catcher adjacent to the open end of the other leg of the U-shaped tube, the further provision of a small tank or sump into which the bottom of the U-shaped tube extends, said tank or sump being adapted to catch the fluid overflowing from said tube, and the provision of a connection between said sump and the with the interior of a manifold, connections between said manifold and a source of water, said 19 Claims. (Cl. 95-434) 1 manifold extending from one leg of the U around the bottom and embracing a substantial portion of the other leg of the U, said manifold terminating in a tank-like vessel having a drain connected thereto and valved so that water is discharged therefrom via said drain when a predetermined level in the vessel has been reached by the water.

Yet another object of' the invention is the provision in a film processor of roller means adjacent to and meeting along a line above the open end of the inlet leg of the first U-shaped tube in the array, said roller means being adapted to remove film from a reel and deliver it to the first U- shaped tube in said array, other roller means engaging the film between adjacent legs of others of the U-shaped tubes in said array for guiding the film from the exit leg of one -U-shapedtube to the inlet leg of the succeeding one, and the further provision of roller means which include a drive .roller and a free roller urged in squeegeeing relation with the drive roller above the exit leg o-f the. washing tube for squeegeeing excess water from the film strip before it enters a drier.

Other objects. and advantages of the invention will be apparent to those skilled in the art and upon a study of the specification and the accompanying drawings.

Referring to the drawings:

Figure 1 is a side elevation partly in section of a complete processor;

Figure 2 is a plan view taken along the lines 2-2 of Figure l, and showing the arrangement for driving the drive rollers;

Figure 3 is an elevation taken along the lines 33 of Figure 1;

Figure 4 is a sectional view of one of the U- shaped tubes taken along the lines 4-4 of Figure 1;

Figure 5 is a cross sectional elevation take along the lines 55 of Figure 1; and m Figure 6 is an enlarged detailed view of the film pickuprdevice.

Referring first to Figure 1, the processor is housed in a cabinet l0 which has a closable door, not shown. The door is omitted in Figure 1 to reveal the entire interior of the casing,and what is seen in Figure 1 would be seen when the door is open, 7

Thecabinet has an intermediate wall H (see also Figure 2) Journaled in a bearing bushing on the wall I i is a stud. shaft 12 upon which the reel vof film 3 to be developed, is supported. Behind the wall H, in spaced relation thereto, is a support plate ii. A bracket i5 has a shaft 16 therein journaled in bearing holes formed in the supportsv l! and it. The bracket I5 has formed i11- tegral therewith a lateral arm portion ii and the boss is which extends through the arcuate hole Journaled on the bosslS is a free roller 2E having a rim 2] thereon formed of rubber-like material. A bearing bushing 22 is pressed into a hole in the supporting wall I l, and a like bushing 23 is pressed into a hole in the support M in alignment with the bushing 22.

A shaft 24 is journaled. in the bearings 22 and 23, and has secured thereto a worm gear 255-, the gear being fixed on the shaft by means of a pin 26 extending through the hub inating end play. The shaft 24 is stepped and supported on the stepped portion is a backing Irubber-like material.

3 washer 29 and a roller 30 which is secured thereon by means of a screw 3| engaging an axially threaded hole in the shaft. The roller 30 has a rim 32 of rubber-like material.

In lateral alignment with and spaced apart from the bearing bushing 22 is a bearing bushing 33 which is pressed into a hole formed in the supporting wall A like bushing 34 is pressed into a corresponding hole in the support plate l4 so that it is in alignment with the bushing 33. A shaft 35 is journaled in the bushings 33 and 34 and carries a worm gear 36 which is secured to the shaft by means of a pin 31 extending through its hub and through the shaft. A collar 38 pinned to the shaft 35 abuts the bearing 34 and a like collar 39 pinned to the shaft abuts the bearing 33. The shaft 35 is stepped, and mounted on the stepped portion is a backing washer 49 and a roller 4| which are secured to the shaft by .means of a screw 42; The roller 4| has a rim 43 of rubber-like material. The supporting wall H and the support plate l4 also carry, in spaced relation to the bearing 33, aligned bearing bushings 44 and 45 respectively, and journaled' in these bearing bushings is a shaft 46 which has pin collars 4'! and 48 respectively abutting the bearings 44 and 45. The shaft also has a worm gear 49 thereon which is keyed thereto by a pin 50. The shaft 46 on its outer end is stepped, and mounted on the stepped portion is a backing washer and a roller 52 which are secured on the shaft by means of a screw 53. The roller 52 also has a rim 54 of rubber-like material. The supporting wall II, and the support plate l4 carry, in spaced relation to the bushing 44, aligned bushings 55 and 56 respectively in which a shaft 5'! is journaled. The shaft has thereon a collar 58 abutting the bushing 55 and a collar :66 which cooperates with the roller 4|, and the axis of the shaft 61 of this roller is substantially on a vertical plane cutting the axis of the roller M. The roller 66' preferably has a rim 68 of The bracket 69 has sup-, 'ported therein a roller ll] which cooperates with the roller 52, and the axis of the shaft H of this roller is substantially on a vertical plane cutting the axis of the roller 52. The bracket 69 is identical with the bracket 66, and with an- 'other bracket to be presently described. There- 'fore, it is believed that a detailed description extends through a sleeve 18 which forms a hubof the roller and is secured therein by means of a set screw 19. An elongated hole 80, formed in the leg 11 has, in alignment therewith, a second elongated hole 8| formed in the leg 16. The

roller 10 is a free roller which cooperates with the roller 52 under the urge of gravity, therefore, the weight of the roller 16 is important. This roller has a rim 82 of rubber-like material so that the film 83, engaged between the rollers 52 and 76, does not come in contact with the metallic surfaces of any roller.

A bracket 84, identical with the brackets 65 and 69, has supported therein a roller 85 which cooperates with the roller 63, and the axis of the shaft 86 of this roller is substantially on a vertical plane cutting the axis of the roller 63. The roller 85 preferably has a rim 8'! of rubberlike material.

A U-shaped conduit 88'has an inlet leg 89 and an outlet leg 99. The axis of the inlet leg is preferably below and substantially in line with the lineof contact between the rollers 29 and 3B, and the axis of the outlet leg 90 is adjacent to the surface of the left side of the roller 4| (as seen in Figure 1). The U-shaped conduit is supported on the supporting wall II as follows: A bracket 9| embraces the conduit near the mouth of the left leg and this bracket is secured to the supporting wall H by means of screws 92; a second bracket 93, which may be identical with the bracket 9|, embraces the left leg 89 of the conduit in spaced relation to the bracket 9| and is secured to the supporting wall I by the screws 92. A bracket 94 embraces the leg 96 near the mouth thereof and is secured to the wall II by means of the screws 92. The lower end (of ;the U-shaped portion per se) of the conduit 88 extends into a receptacle 96. This receptacle is removably supported in the cabinet I6 on a plate member 9'! which is secured to a horizontal partition 98 by means of wing bolts 2, and which has a portion 97a which extends through an opening 99 in said partition and forms a resting place for the container 96.

Mounted on the vertical wall H is an angle bracket |90a which is secured thereto by means of screws |0|a, and secured to the horizontal portion of this bracket is a mounting plate |02a of a pump I93a. The pump has a boss 1411 which extends rearwardly through a hole |65a formed in the vertical wall II, and the shaft of the pump may have secured thereto agrooved pulle |06a.

A second U-shaped tube I91 isidentic'al with the U-shaped tube 88. It has a vertical inlet leg I98 and a vertical outlet leg I 99. These legs are joined b a U-shaped portion H9 to form a unitary structure, and the U-shaped portion ||0 extends into a receptacle III which is identical with the receptacle 96. The receptacle III also rests on the plate 91 so that by removing the wing bolts 2 the plate may be lowered with both the receptacle 96 and the receptacle l resting thereon. The inlet legs 89 and IE8 both have apertures ||3 formed therein near the top thereof and embracing the legs about the apertures are casings Ma and I I4 respectively. Since the leg 89 of the tube 88 is shown in elevation, the casing ||4a mounted thereon is also shown in elevation, and the leg I98 of the tube It! is shown in section; the casing 4 thereof is shown in section. The casings ||4a and II 4 are secured to the respective legs 89 and I08 in fluid-tight relation both above and below the apertures H3, and a pipe I I5 has its upper end connected to the casing 4. A like pipe ||5a is connected to the casing 4a. The lower'end of the pipe ||5a is connected to the discharge port ||6a of the pump |03a and thereby the fluid pumped by the pump |03a is delivered "into the casing use and it enters the we ta via the apertures therein like the apertures I13.

the top thereof, are perforations H9, and like perforations l I9a are formed in the leg so of the U-shaped tube 88.

The pipe II5a' delivers fluid from the pump I031; via the casing H40: and the perforations --I I3a,"and this liquid fiows down the leg 39 around the U-shaped-bottom of the conduit and up the leg 90 until-it encounters the perforations 'IIBa. These perforations allow the fluid to flow out into the flared portion Ilsa and thence the liquid flows downwardly between the tubular member Illa and the outer surface of the leg 99 and is delivered into the receptacle 93.

A pipe I2Eia extends below the liquid level in the receptacle 93 and .has its upper end connected to the inlet I2Ia of the pump. 7

I From the above it will be observed that there is a continuous circulation of the processing fluid from the receptacle 93 via the pump and via the pipe II5a and the casing II 5a into the leg 89 of the U-shaped conduit, thence around the conduit in the direction of the movement of the film and outwardly through the perforations II9a into the flared portion IIBa and thence downwardly within I I'Ia to the tank.

The pipe H5 delivers fluid from the pump I93 via the casing I I9 and the perforations I I3. This liquid flows down the leg I93 around the U-shaped bottom of the conduit and up the leg I39 until it encounters perforations II9. These perforations allow the fluid to flow out into the flared portion H8 and thence downwardly between the tubular member I I! and the outer surface of'the leg I39, and is delivered into the receptacle III A pipe I23 connected to the-inlet IZI of the pump I93 delivers liquid from the receptacle III to the pump thereb a continuous circulation of the processing fluid from the receptacle III is circulated in the manner described through the U-shaped tube I91.

A third U-shaped tube I22 is mounted on the wall II so as to be arrayed in alignment with the tubes 83 and IIl'i. This tube is employed for washing the film after it has been processed in the preceding tubes, therefore, no pump is necessary if a source of Water under pressure is available. The U-shaped tube I22 has a series of perforations I24 formed in its walls. A U-shaped water conduit I25 embraces the U shaped tube I22 throughout its entire length, with the exception of a portion of the inlet leg I23 near the mouth thereof anda portion I26 of the outlet leg thereof. The tube I22 is secured within the U-shaped water conduit in any suitable manner and the combination is supported on brackets I92 and I93 which are mounted on the wall II. The U-shaped conduit 125 has an enlarged portion I21 which is sealed to the inlet leg I23 in fluid tight relation at the point I28. The portion I21 has a pipe connection I29 communicating therewith and connected to this is a pipe I39 ,Which terminates ina valve I3] belowth hori zontal partition 98, and this valve is adapted to be connected to a source of water under pressure.

The right leg I32 of the U-shaped conduit I25 has its upper end enlarged to form an open tank or receptacle I33 and the right wall of this receptacle has a flared portion I34 which is positio'ned beneath the roller 63. A drain pipe I35 has its upper end threadedly engaging a boss I36 formed on the tank I33 and communicates with the interior of the receptacle I 33. A ball float-I31 normally rests on a seat formed adjacent to the This ball is retained in this portion of the receptacle I33 by means of a cag I38. The lower end of the pipe I35 is adapted to be connected to a conduit for conveying the waste water away from the device. Where the pipes I39 and I35 pass through the horizontal partition 98 they are secured in shakeproof relation b means of interlocking threaded bushings I39. When the machine is set into motion the receptacles 96 and III have the necessar processing fluids therein and the valve I3! is open so that water will flow into the portion I2I of the U-shaped conduit I32, and this water flows both within the U-shaped tube and the u shaped conduit entering the U-shaped tube via the perforations I24. Now, when the water passes around the U-shaped conduit and the U-shaped tube it enters the tank I33 and starts rising therein. When it has reached a level suflicient to raise the iloat I37, water may leave the receptacle I33 via the pipe I35. Thus the ball float arrangement makes sure that not less than a predetermined level of water is always present in the U-shaped tube I22 when the machine is operating.

Between the rollers 52 and I53 the wall II carries a boss Itfi which has a hole therein threadedly engaged by a shouldered screw MI. Journaled on the shouldered screw MI is a bracket I42 carrying a shouldered shaft I43 upon which a squeegee roller I44 is journaled, the roller being retained thereon by means of an end screw I45. The bracket I32 has a spring boss I46 thereon to which one end of a spring IE1 is connected. The other end of the spring is con} nected to a post I98 on the wall II, thus the bracket I42 and its roller I44 are urged upwardly so that the roller me squeegees water from the surface of the film leaving the leg I25 of the tube I22. The film, after it passes between the rollers 63 and the squeegee roller I44, encounters a guide member I49, which has a clearance opening formed therein for the roller 83, and passes between the rollers 63 and 85 and thence downwardly into a drying conduit I59. To insure the proper entrance of the film into the drying con duit a. guide member I5I is provided in spaced relation to the guide I49 below the ce'nter line of, and to the right the roller 63 (as shown in Figure l). Drying air is led into the drier via a passage I92. Since the drier per se forms no part of the present invention, as any good film drier may be used, it will not be described herein in detail. It is usual to supply such driers with warm air and, consequently, a blower and an air heater may be employed. The film 83,

I as it leaves the drier, encounters a drive roller I52 carried on a driven shaft I53 and having a rubber-like rim, and a cooperating free roller I54 which is journaled on a shaft I55 supported on a bracket I53 which is in turn journaled on a shouldered screw I51 supported in the wall II.

A spring I38 has one end connected to the bracket I56 and the other end secured to a post I59 extending from thewall II.

Spaced apart from the rollers I52 and I54 is a take-up reel shaft I68 which carries a takeup reel I6I. The end of the film is provided with a leader having several holes near the end thereof and these holes engage one or more of the hook members I62 provided on the hub of the reel. For guiding the end of the leader to the hooks a pivoted member I63 has aligned lugs I64 which are pivotally supported on the stud shaft I65 mounted in the plate II. The member consists of a channel strip I66 having spaced pairs of lateral lugs I61 thereon; each pair of lateral lugs supports a shaft I68 and journaled on each shaft is a, free roller I69. The film 83 passes down the channel and is retained therein by the rollers I69, and the pivoted member I63 is urged toward the reel by means of a spring I18 which has one end secured to the post I65 and the other end bearing against the pivoted member I63. plate II is provided for limiting the swing of the pivoted member I63 in a counter-clockwise direction as seen in Figure 1. Now when the film 83 passes down the channel I66 and is engaged by one of the hooks I62 it begins winding up on the reel I6I and as the film builds up on the reel the pivoted member I63 is displaced toward the left or in a clockwise direction.

Mounted between the wall II and the support plate I4 is a reduction gear box I12 which has an input shaft I13 carrying a pulley I14. Extending 98 degrees with respect to the input shaft I13 are aligned output shafts I and I16. The

shaft I15 is journaled in bearing brackets I11,

secured to the plate II, and I18 secured to the support plate I4. The bearing support I18 is positioned on the plate I4 so as to leave the clearance for the arm I1. The shaft I15 has secured thereto a worm which meshes with the worm gear 36. The shaft I16 is journaled in bracket bearings I8I and I82 which are secured to the plate I I, and the shaft I16 carries a worm I83 which meshes with the worm gear 49, and a worm gear I84 which meshes with the worm gear 68. The pulley I14 may be connected by means of a belt to a corresponding pulley on a motor, not shown, for driving the same and consequently driving the shafts I15 and I16 at a substantially slower rate and thereby causing the rollers 38, M, 52 and 63 to rotate in unison.

The pumps I83 and E8311 may be driven by a motor, not shown, having a pulley corresponding to and belted to pulleys I86 and I85a on the pumps I83 and I83a respectively. Since the pumps are driven at a high rate of speed no gear reduction is necessary for it is preferable to move the processing fluids at a substantial speed so as to wash off any deposits on the surface of the emulsion.

Referring to Figure 4, the processing and washing tubes 88, I81, and I22 may be formed of strip material in the form shown in Figure 4. One strip has spaced portions I 85 and I88 the faces of which are in alignment. The strip also includes a portion I81 which is parallel to the portions I 85 and I88. Joining the portions I85 and I81 is an annular portion I 88 and joining the portions I86 and I81 is an amiular portion I89. The portion I86 has a narrow web I98 the surface of which is substantially at right angles to the surface of the portion I86. Now when a second strip, in which the same portions bear the same numerals followed by the letter a, is

positioned in cooperative relation with the first A stop pin I1I mounted in the strip, the portion Ia abuts the right angled portion I98 and the two edges are secured in fluid-tight relation by a line of welding I9I. Likewise, the portion I85 of the first strip abuts the right angled portion I9l1a of the second strip and the two edges are secured together in fluidtight relation by a line of weld I9Ia. When the tube is so formed the interior of the apex formed by the portions I89 and I88a clear the edge of the film 83 and likewise the inner apex formed by the portions I88 and I89a clear the right edge of the film 83. When the film is in position in the tube it divides the stream of processing fluid passing through the tube into two parts, as may readily be seen in Figure 4.

For guiding the film 83 into the inlet leg 89 of the U-shaped tube 88 a guide strip I93 has a rectangular opening formed therein through which the roller 28 extends, and a second guide strip I94 has a rectangular hole therein through which the roller 38 extends. These guide strips are secured to the inlet le 89 and extend upwardly to a position where the end of the film may be inserted between them and engaged by the rollers 28 and 38. I

Fo guiding the film from the outlet leg 98 of the tube 88 into the inlet leg I88 of the tube I81, the guide strip I95 is secured to said legs so as to guide the film onto the roller 4| as it leaves the leg 98. This guide strip has a rectangular opening formed therein through which the roller 66 may extend to contact the roller M. A second guide strip I98 is secured to the adjacent faces of the legs 98 and I 88 and has a rectangular opening through which a portion of the roller 4| extends so that film leaving the leg 98 passes between the guide strips I95 and I96 and passes over the roller 4| and between thi roller and the roller 66, and thence into the inlet leg I 88 of the tube I81. Between the outlet leg I89 and the inlet leg I23 guide strips which are identical with the guide strips I95 and I 96 are provided, and since these are identical they are designated by the same numerals followed by the letter a.

What is claimed is:

1. In a film processor, a U-shaped conduit having its legs vertically disposed, film supporting and conveying means above the open ends of said legs for delivering film into the inlet leg of said conduit for pushing said film down said leg, around the bottom thereof and up the outlet leg thereof and for removing said film from the outlet leg thereof at substantially the same rate, a tank at least a portion of which is positioned below the level of the upper ends of said legs, a circulating pump having its inlet port connected to remove fluid from said tank having its outlet port connected to deliver said fluid into said inlet leg, and vertical overflow means carried on said outlet leg below the open end thereof via which fiuid therefrom may return by gravity to said tank, said overflow means including a tubular guide embracing said outlet leg and extending into said tank.

2. In a film processor, a plurality of upright U- shaped conduits having thei legs vertically disposed arranged in a series with film guides therebetween, means for supporting and for conveyin and pushing a film through said conduits in a series of upright and inverted loops, at least two of said conduits having individual circulating means connected thereto for circulating processing fluid therethrough in the direction of movement of the film, thereby abetting the pushing effect by said first means overflow means on each of said last mentioned conduits, and individual tubular guide means vertically disposed on and embracing the leg of each of said conduits having said overflow means therein to lead fluid therefrom to the respective circulating means.

3, In a film processor according to claim 2, in which each of said circulating means is individually interconnected with a tank for containing processing fluid, and in which each of said tubular guides insures the return of the overflow fluid to the tank associated with its respective circulating means. a

4. In a film processor wherein a plurality of upright U-shaped conduits is arranged in a series, and in which means'is provided for supporting and conveying film through all said conduits in a Series of upright and inverted loops, one of said conduits forming a washing conduit and comprised of a U-shaped member, a second U- shaped member within said first member, said first member being imperforate and having means on its inlet end for connection to a source of water under pressure and having its outlet end substantially enlarged and carrying means therein for maintaining a constant liquid level therein, said second member having its walls perforate, whereby it functions to guide the film there through and to lay open both surfaces of the film to the washing action of the water, and overflow means connected to said enlarged portion of said first member.

5. A film processor according to claim 4, in which said means for supporting and conveying the film include a drive roller having its face tangent to a plane extending through the outlet leg of said washing conduit, and in which a pivoted bracketcarries a squeegee roller cooperating with and spring loaded toward said last men-- tioned roller so as to firmly engage the film and remove wash-water therefrom.

6. In a film processor, a plurality of upright U- shaped conduits arranged in a series with film guide therebetween, film supporting and conveying means between said conduits and said guides for pushing the film through said conduits and guides in a series of upright and inverted loops; individual circulating means connected to at least one of said conduits for circulating processing fluid therethrough in the same direction as the film is moved therethrough, thereby abetting the pushing action of said first means, a tank positioned beneath said last mentioned conduit and having the lower end of the latter extending into it, said circulating means including a pump having an inlet connection extending into said tank below the liquid level therein and having its outlet connected to deliver said fluid to one leg of said last conduit, and overflow means including a vertical tubular guide mounted on and embracing the other leg of said conduit for returning said fluid to said tank.

7. In a film processor, a casing having an inher vertical wall and a horizontal wall therebelow, a plurality of upright U-shaped conduits mounted on said vertical wall in a series with film guides therebetween, external film supporting and conveying means for pushing film through said conduits and said guides in a series of upright and inverted loops, a removable panel in said horizontal wall, an opening tank positioned on said panel and having the lower end of at least one of said U-shaped conduits extending into it, and circulating means for removing liquid from said tank and delivering it to the inlet leg of said last conduit so that it moves in the' direction of movement of the film therethrough and abets the pushing action of said first means, and overflow means on and comprising a vertical tubular guide embracing the exit leg of said last conduit at least below the upper end 'jof said tank for returning said fluid to said tank, said panel being adapted to be removed so as to lower said tank to a point beneath said horizontal wall.

8 .'""In a film processor, a U-shaped conduit, film supporting and conveying means for delivering film into the inlet leg of said conduit, pushing the film through the conduit and for removing film from the outlet leg of said conduit at substantially the same rate, an opening tank positioned below the levels of the upper ends of said legs, a circulating pump connected to receive fluid from said tank and to deliver fluid to one le of said conduit, overflow means on the other leg of said conduit via which fluid therefrom may return by gravity to said tank, said last means including a series of perforations formed in said last mentioned legnear the upper end thereof and a vertical tubular guide embracing said last leg and having its upper end adjacent to said perforations enlarged to receive fluid leaving said last mentioned leg via said perforations, and individual motor means for driving said circulating pump.

9. In a film processor, a U-shaped conduit, a U-shaped member within said conduit having its walls perforate thereby providing free communication between the interiors of said conduit and said member, means to convey a film through said U-shaped member, connections between one end of said conduit and a source of fluid, and overflow means connected to the other endof said U-shaped conduit whereby both surfaces of the film are freely contacted by said fluid via the perforated wall of said member.

10. In a film processor, a U-shaped conduit, a U-shaped member within said conduit having its walls perforate thereby providing free communication between the interiors of said conduit and said member, means to convey a film through said U-shaped member, connections between one end of said conduit and a source of washin water, and overflow means connected to the other end of said U-shaped conduit whereby both surfaces of the film are freely contacted by the wash water via the perforated wall of said member.

VERNEUR E. PRATT. GEORGE F. GRAY.

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

UNITED STATES PATENTS Number Name Date 1,172,116 Devericks Feb. 15, 1916 1,292,230 Barbieri et al. Jan. 21, 1919 1,707,709 Comstock Apr, 2, 1929 1,881,612 *Ingman et a1. Oct. 11, 1932 2,085,188 Gerlach June 29, 1937 2,401,185 Pratt et a1 May 28, 1946 2,428,681 Pratt et a1. Oct. 7, 1947 FOREIGN PATENTS Number Country Date 99,619 Germany Oct. 15, 1898 350,544 Germany Mar. 25, 1922

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