US2432756A - Sludge tank having a u-shaped conduit having arm portions inclined downward to the lower part of said tank and a conduit opening into said tank connecting said portions - Google Patents

Description

-HAPMAN 2,432,756 SHAPED CONDUIT HAVING ARM PORTIONS INCLINED Dec. 16, 1947.

SLUDGE TANK HAVING A U DOWNWARD TO THE LOWER PART OF SAID TANK AND A CONDUI'I' OPENING INTO SAID TANK CONNECTING SAID PORTIONS Filed Jan. 15, 1944 3 Sheets-Sheet 1' n 2 a M \w ULHHHH. x Wil uhl hl hnl Ri n n E 17 (Q 3 I w r u 2 I 2 IIIJ 4 3 w M 15% avg zi! Dec. 16, 1947. w, HAPMAN 2.432.756

SLUDGE TANK HAVING A U-SHAPED CONDUIT HAVING ARM PORTIONS INCLINED DOWNWARD TO THE LOWER PART OF SAID TANK AND A CONDUIT OPENING INTO SAID TANK CONNECTING SAID PORTIONS Filed Jan. 15, 1944 3 Sheets-Sheet 2 INVENTOR.

Dec. 16, 1947., w, HAPMAN 2,432,755

SLUDGE TANK HAVING A U-SHAPED CONDUIT HAVING ARM PORTIONS INCLINED DovmwARD TO THE LOWER PART OF SAID TANK AND A CONDUI'I OPENING INTO SAID TANK CONNECTING SAID PORTIONS Filed Jan. 15, 1944 3 Sheets-Sheet 3 I WW M SLUDGE TANK HAVING DUIT HAVING ABM AND INTO SAID TANK TIONS A U-BHAPED GON- PORTIONS INCLINED THE LOWER PART OF CONDUIT OPENING CONNECTING SAID POR- Henry w. Hapman, Detroit, Mich. Application January 15, 1944, serum. 51am 14 Claims. (01. 210-55) The present invention relates to self-cleaning coolant tanks, and more particularly, to an apparatus for collecting sludge and the like from said tank.

The primary object of the invention is to provide a self-cleaning coolant tank in the system of a grinding machine or the like employing a coolant for reducing the temperature of the work while being ground and to provide a device which is portable and may be readily moved from one location to another adjacent the grinding machine.

Another object of the invention is to provide a, coolant tank of the above-mentioned type having a sludge conveying and collecting system iorcontinuously moving the sludge and other foreign matter in the coolant liquid so that the coolant liquid may be recirculated to the grinding machine. 1

Another object of the invention is to provide a self-cleaning coolant tank of the above-mentioned character which may be operated continuously or during intervals so "as to maintain the coolant liquid in a clean condition and to prevent the collection of large quantities of sediment in the bottom of the tank to. contaminate the coolant liquid.

Another object of the invention is to provide a self-cleaning coolant tank which is entirely automatic and requires very little attention on the part oi the grinding machine operator so as to maintain the coolant liquid free of sediment and sludge collected during the grinding operation.

Another object of the invention is to provide an inlet for the coolant liquid as it is discharged from the grinding machine directly above a compertinent formed by a bailie plate so that foam and the like may be removed from the surface of" the liquid through an opening at one side of the coolant tank directly opposite the inlet.

Another object of the invention is to provide a self-cleaning coolant tank of the above-mentioned character having a uniquely constructed sediment and sludge collector of the endless conveyor type which is adapted to travel a circuitous path and traverse the bottom 01' the self-cleaning coolant tank during a portion of said circuitous path.

Other objects and advantages of the invention will become apparent during the course of'the following description of the accompanying drawings, wherein:

Figure 1 is a side elevational view of the cool-- ant tank embodying the invention,

illustrating the same in position adjacent the centerless grinding machine, and illustrating the manner in which the conveyor is arranged to collect sludge and sediment from the tank and convey the same to a point of discharge;

Figure 2 is a top plan view of the coolant tank showing the conveyor disconnected therefrom to illustrate the general shape and design of the casing structure;

Figur 3 is a top plan view of the conveyor tubing illustrating the general shape thereof and showing the reduced intermediate section for being welded to the sloping walls of the coolant tank so that the free ends may project upwardly to a point of discharge; 7

Figure 4 is an enlarged cross-sectional view illustrating the manner in which the. sloping walls of the coolant tank are welded to the intermediate portion 01' the'conveyor tube;

Figure 5 is a vertical cross-sectional view showing the discharge end of the conveyor tubes greatly enlarged, illustrating the manner in which the sludge and sediment is removed by the endless conveyor;

Figure 6 is a plan view showing in detail one of the conveyor flights for the conveyor illustrating the manner in which the same is cut outlto accommodate the conveyor chain;

Figure 7 is a transverse cross-sectional view through the conveyor chain illustrating the manner in which the conveyor flights are bolted thereto by oppositely extending lugs on opposite sides of the conveyor chain;

Figure 8 is a cross-sectional view online 8-8 in Figure 1 showing th manner in which the free ends of the conveyor tube are welded to an interconnecting plate which is welded or otherwise fastened in place; I

Figure 9 is a top view greatly enlarged showing the manner in which the motor support and conveyor sprocket are adjustably supported adjacent the free end of. the conveyor tube;

Figure 10 is a longitudinal sectional view on line lll-I|l in Figure 9 looking in the direction of the arrows, illustrating in detail the manner in ner in which the sprocket 3 which'the adjustable motor and sprocket supporting plates are carried by the free ends of the conveyor tubes; and

Figure 11 is an end elevational view of the adjustable motor supporting base showing the manis supported for being driven by the motor on the underside of said plate.

Brief description of the invention The invention broadly comprises a tank having sloping bottom walls and battle partitions for the reception of a coolant fluid circulated over the grinding wheels of a centerless grinder so as to cool the work during grinding. The coolant with the particles of metal or the like is then returned to the tank and the sludge therein and other sediment is collectedin the bottom of the tank where it is adapted to be removed by an endless conveyor arranged and positioned so as ,to convey the sludge and sediment to a point of discharge remote from the tank. In grinding machines of the centerless type, the coolant tank associated with the circulatory system becomes filled with sediment and sludge to such an extent as to stop circulation of the coolant liquid and create obnoxious odors, and it is frequently necessary to remove the sludge and sediment by manual labor which requires the centerless grinding machine to be thrown out of operation until the removal of the sediment and sludge has been completed.

The above objections and disadvantages are overcome by providing a uniquely constructed tank which may be presented to the discharge of the centerless grinder so as to collect the coolant with the abrasive and other particles so that the particles will be collected at the bottom of the tank and discharged over a suitable receptacle which may be easily emptied when full and thereby prevent the centerless grinder from being out of operation over long periods of time and at the same time maintain the coolant liquid in clear, clean condition. Another advantage inherent in the coolant tank embodying this invention resides in the fact that foam and the like may be removed from the tankfrom the liquid level thereof adjacent the inlet opening of the tank so that said foam will not overflow and cause objectionable odors and appearance.

Detailed description of the invention In the drawings, Figure 1 shows a preferred form of the invention comprising a collection and sediment tank of rectangular construction having a pair of side walls 5 connected at one end by an end wall I and at the other end by an end wall 8. Connecting the side walls 6 and welded or otherwise secured to the sloping edge 9 thereof is a sloping bottom wall ll (Figure 4). having a depending flange portion l2 and the extreme lower portion of the sloping bottom wall II is tapered inwardly at both ends as at IS. A sloping bottom wall l4 extends from the end wall 8 to a point adjacent the lower end of the sloping wall H and said end wall is also provided with a depending flange l5 similar to the flange l2 and arranged in parallel relationthereto. The sloping wall i4 is slightly reduced in width as shown in Figure 2 in dotted lines and is spaced from the side walls 6 and the tapered portion l3 of the sloping wall as well as the reduced sloping wall II. A plate I1 is welded in place to the side wall 6 adjacent each end or side of the reduced sloping bottom wall l4. Said -to the top edge of the side walls plates may be welded along the edges to the reduced sloping wall l4 and may have extensions adjacent the lower portions provided with armately cut out areas to facilitate the passage of the conveyor structure which will be hereinafter more fully described.

A cover plate l9.is welded or otherwise secured 6 and end walls I and 8 and said cover l9 terminates at one of its ends a short distance from one of the walls 1 so as to provide a space therebetween, a portion of which is adapted to be closed by a hinged closure 20 hinged to the top wall l9 as at 2|. The remaining portion of the opening is closed by a frame 23 having sloping walls 24 to form a framework for a screened inlet 25. One endof the casing has its side wall 6 cut away as at 26 at a point near the liquid level of the coolant tank so that foam collecting on the top of the liquid may be withdrawn or removed by scooping the same toward one end of the casing. The closure 20 is adapted to facilitate the replenishing of the coolant liquid and the addition of various ingredients thereto from time to time. Extending between the side walls 6 and terminating adjacent the sloping bottom wall I I is a partition 28 which extends downwardly from the edge of the top wall l9 so as to form a compartment adjacent the entrance or coolant liquid inlet so that the heavier particles will be directed downwardly toward the sloping bottom wall II when the coolant liquid is circulated through the tank. Similarly, a partition wall 29 extends between the reduced sloping floor l4 and terminates at short distance from the top wall 19 and said partition interconnects the plates l1 and the end wall 8 so as to form a chamber for the sludge and sediment in the tank. The coolant liquid passing through the tank is adapted to overflow the baflie 29 at the top thereof as at 30 so as to fill a compartment having tapering walls 3| and an end wall 32. The end wall 8 forms the other wall of the liquid coolant chamber and completes the structure with the bottom wall 33 extending between the end walls 8 and 32. The top of the liquid coolant chamber on the left side of the tank is closed by a cover plate 34, and mounted on said cover plate is a circulatory pump apparatus 35 including a motor and suitable gearing with the motor shaft extending downwardly through a tube 36 to a point adjacent the floor 33 where it is connected to the rotor of a sump pump 31. The outlet side 38 of the sump pump is connected by a tube or conduit 39 to a supply pipe 40 the end of which is connected to the centerless grinder for supplying the coolant liquid to the wheels thereof. The sump pump 31 may be of the centrifugal type and is provided with a centrally positioned inlet in communication with the coolant liquid chamber to the left of the coolant tank.

Secured to the depending flanges 12 and iii of the respective sloping bottom walls II and I4 is a short length of pipe 4| (Figure 4) diametrically divided and cut away a distance equal to the space-between the edges of the sloping wall l4. The depending flanges l2 and I5 are welded as at 42 to the edge of the divided pipe to form a trough 43 of semi-circular shape. The ends of the semi-circular trough'43 are welded to the plates l1 adjacent the openings therein so as to aid in spacing said plates. Elbow sections 45 are welded or otherwise secured to the outer sides of the plates l1 and the ends of the semi-circular trough portion 43, and said elbow fittings 45 are provided with relatively straight portions 48 terminating in angularly disposed discharge and inlet ends 41 and 48 respectively. The extreme free ends of the pipes 41' and 48 are flared outwardly as at 48 and 58 to allow the free passage of the endless conveyor adapted to travel through the tubes 41 and 48 and also traverse the semicircular trough 43. As shown in Figure 1, the relatively straight portions 48, 41 and 48 of the conveyor tubes are angled with respect'to the horizontal and are inclined upwardly from the semi-circular trough 43 to a point of termination adjacent the top 5. It is to be noted that the free end portions 41 and 48 extend along the side walls 3| of the coolant chamber and an angle bracket 52 is welded to the end wall 32 of the coolant chamber for supporting the tubes 41 and 48 at each end thereof.

Mounted between the free projecting ends of the tubes 41 and 48 is a supporting plate 53 having obliquely cut edges 54 which are adapted to be welded as at 55 (Figure 8) along the top of the conveyor tubes 41 and 48. The plate 53 is adapted to hold the free ends of the conveyor tubes together and to form a support for a motor sprocket drive including a pair of spaced parallel bars 58 (Figure 9) bolted or otherwise fastenedto the plate 53 as at 51. The bars 58 project beyond the plate 53 and bolted to the bars. 58 is a pair of similar bars 58 strips 58.. Bolts 58 spaced by means of spacer are passed through the strips 58, 58 and 58 and it is noted that the space between the strips 58 and 58 forms receiving a sliding plate 8| having a lug at one end thereof as at 82 to which is pivotally attached a screw-threaded shaft 83 by means of a, pivot pin or the like as at 64.. The screw shaft83 is received in an aperture formed in a, lug 85 connected with the plate 53 and suitable nuts 88 are mounted on the rod 63 in threaded relation therewith, and on opposite sides of the lug 65 to permit adjustment of the sliding plate 6| along the ways provided by the spaced parallel bars 55 and 58.

Secured to the sliding plate 8| is an electric motor 88 having a reduction gear casing 58 in the lower portion thereof and the shaft of said reduction gearing is adapted to project through an opening 18 in the plat 8| so as to be drivingly connected to a. sprocket wheel 1| suitably keyed thereto as by means of a ib and slot connection. A spacer sleeve 12 is mounted on the shaft between a washer 13 on the underside of the plate 8| and the sprocket 1| o as to space the sprocket a suflicient distance from the plate El and perwit the conveyor structureto pass under. A switch 14 is provided on the motor 88 and said switch maybe connected with a domestic source of current to supply the motor 88.

Extending through the conveyor tubes 41. and

88 in the relativelystraight sections 46 and trained over the sprocket 1| is a conveyor chain generally designated by the reference character 15 comprising links 18 having alternate pivot pins 11' and. pivot pin socket members 18. Each chain link 16 is provided with a pair of oppositely extending wing-like lug members 18 projecting from opposite sides of said links in a lateral direction and the free ends of said lugs are apertured for the passage of bolts 88 which bolts are adapted to pass through the openings .8l'in the conveyor flight members 82 (Figure 6). Nuts 83 may be threaded on, the bolts 88.'to retain the disc-shaped flights 82 in place and said flights are backed by a g-uideway for a disc-like plate 84 to-add a certain amount of the upper wheel 1| as the flights pass therearound. It is to be noted that the conveyor flights 82 and backing plates 84 while being of difierent diameters are shaped and formed so as to traverse the trough 48 and remove the sediment or sludge therefrom deposited from the tank 5.

The discharge conduit 41 is provided with a shield plate 88 welded or otherwise fastened in place as shown in Figure 5 and said shield plate is adapted to catch drippings from the flared end 48 and prevent the same from flowing downwardly along theoutside of the conveyor tube 41.

The side walls 8 of the tank 5 are provided with vertical leg members 88 while the end wall 32 of the coolant chamber is provided with an ad- Justable leg 88 having a foot portion 8| to facilitate the supporting of the less grinder generally indicated by the reference character G. The leg 88 is adjustably held in place by means of bolts or the like as at 82. A relatively large receptacle 83 may be positioned under the sprocket wheel 1|, discharge end of the conveyor tube 41 and directly below the depending lip 88 so as to catch the discharge' from the tank 5'when the motor 88 is in operation, and facilitate the removal of the sludge and sediment therein from a, point remote from the tank.

The grinder G is typical of a conventional centerless grinder and embodies a base B having spindle supports C for rotatably mounting a pair of grinding wheels D. The frame B is provided with an extension trough E directly beneath the grinding wheels D so as to catch and collect the coolant liquid after the same has passed over the ma terial being ground between the grinding wheels D. A dischargeopening or spout F is formed in the trough E and said discharge spout F is adapttrough E directly into the tank 5. After the coolant liquid passes into the tank' through the screened opening 25 it is caused to travel downwardly adjacent the sloping floor II and under the baille 28 so that the heavier particles will be guided downwardly toward the semi-circular trough 43. The coolant liquid will then pass over the top edge 38 of the baflle wall 28 where it will enter the coolant chamber so as to be recirculated back to the grinder G by means of the centrifugal sump pump 31 through the tube 48. The tube 48, generally a part of the grinder, is coupled with end Of the discharge tube 38 and upon operation of the motor 35 circulation of the liquid will be effected. As the sludge or sediment c01- lects in the semi-circular trough 43 in the lower part of the sloping walls II and I4 it may be desired to remove the sludge so as to be collected in a receptacle 83. In order to remove the sludge. the motor 68 is started by manipulating the switch 14 so as to cause the conveyor chain to traverse the sprocket wheel 1| and pass through the conveyor tubes 41 and 48 so as to withdraw the sludge and sediment to the outer flared end 48.

In addition to permitting the conveyor flight to pass around the sprocket wheel, the slots 88 allow the coolant liquid to return from successive flights as they reach the flared opening 48 and thereby prevent pumping of the coolant liquid and removal of the sludge S..

If desired, the pipe section 4| may be slightly tank adjacent a center-' smaller in diameter than the conduit sections 46,

41 and 48 so that as the conveyor flights traverse the semi-circular trough 43, a relatively tight fit therebetween will be had while conveyor flights travelling through the conveyor tubes 48, 41 and 48 will be permitted a greater clearance so that the coolant liquid may run back from one flight to the other and prevent the same from being pumped out of the discharge tube 41. It is also to be noted that the flared end 49 of the discharge l0 tube 41 relieves the flights of any pumping action as they near the flared end by the greatly increased diameter of. the discharge pipe so as to further eliminate pumping of the coolant liquid as it travels toward said discharge.

When the conveyor 15, including the chain structure 16 and the flight elements 82, has become worn on one of their diametrical sides, the conveyor may be removed and reversed so as to bring the other diametrical side in contactual 20 wiping engagement with the tubes 84 and the tubes 41 and 48 and trough 43. Since it is necessary to mount the conveyor 1n the position reversed to its position shown in the drawing during such a change, it is obvious that the motor 68 would have to be reversed so as to change the direction of conveyor travel. In this event the discharge tube 48 would become the outlet and the tube 41 the inlet.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred embodiment of the same and that various changes may be made in the shape, size and arrangement of parts without departing from the spirit of the invention or the 5 scope of the subjoined claims.

What I claim is:

1. A sludge removal apparatus comprising a receptacle having a downwardly-sloping bottom wall, an approximately U-shaped conduit struc 4n ture having tubular arm portions inclined downward to the lower part of said receptacle and a connecting conduit portion extending through the lower part of -said receptacle and interconnecting said arm portions, said connecting portion hav- 45 ing an opening in the upper part thereof for the passage of the sludge settling downward in the receptacle, an endless conveyor mounted in said conduit structure and having a portion extending externally thereof, and power-actuated driving mechanism drivingly engaging the external portion of said flight conveyor for moving said conveyor'through said conduit structure.

2. A sludge removal apparatus comprising a receptacle having. a downwardly-sloping bottom wall, an approximately U-shaped conduit structure having tubular arm portions inclined downward to the lower part of said receptacle and a connecting conduit portion extending through the lower part of said receptacle and interconnecting said arm portions, said connecting portion having an opening in the upper part thereof for the passage of the sludgesettling downward in the receptacle, an endless conveyor mounted in said conduit structure and having a portion extending externally thereof, and power-actuated driving mechanism drivingly engaging the external portion of said flight conveyor for moving said conveyor through said conduit structure, said driving mechanism including a driving wheel mounted betweenandadiacent the outer ends of said arm portions of said conduit structure and. drivingly engaging said conveyor.

3. A sludge removal apparatus comprising a receptacle having a downwardly-sloping bottom nal portion of said wall, an approximately U-shaped conduit structure having tubular arm portions inclined downward to the lower part of said receptacle and a connecting conduit portion extending through the lower part of said receptacle and interconnecting said arm portions, said connecting portion having an opening in the upper part thereof for the passage of the sludge settling downward in the receptacle, an endless conveyor mounted in said conduit structure and having a portion extending externally thereof, and power-actuated driving mechanism drivingly engaging the exterflight conveyor for moving said conveyor through said conduit structure, said driving mechanism including a driving wheel mounted between and adjacent the outer ends of said arm portions of said conduit structure and drivingly engaging said conveyor, the lower portions of said flight conveyor being guided solely by said conduit structure whereby to obviate guide wheels in said receptacle.

4. A sludge removal apparatus comprising a receptacle having a downwardly-sloping bottom wall, an approximately U-shaped conduit structure having tubular arm portions inclined downward to the lower part of said receptacle and a connecting-conduit portion extending through the lower part of said receptacle and interconnecting said arm portions, said connecting portion having an opening in the upper part thereof for the passage of the sludge settling downward in the receptacle, an endless conveyor mounted in said conduit structure and having a portion extending externally thereof, and power-actuated driving mechanism drivingly engaging the external portion of said flight conveyor for moving said conveyor through said conduit structure, said conduit structure having bends therein adjacent the junctions of said arm portions with said connecting portion and said flight conveyor directly engaging the inner walls of said bends for guidance and alteration of direction of travel.

5. A sludge removal apparatus comprising a receptacle having a downwardly-sloping bottom wall, an approximately U-shaped conduit structure having tubular arm portions inclined downward to the lower part of said receptacle and a connecting conduit portion extending through the lower part of said receptacle and interconnecting said arm portions, said connecting portion having an opening in the upper part thereof for the passage of the sludge settling downward in the receptacle, an endless conveyor mounted in said conduit structure and having a portion extending externally thereof, and power-actuated driving mechanism drivingly engaging the external portion of said flight conveyor for moving said conveyor through said conduit structure, the lower part of said receptacle having openings in its opposite ends aligned with saidconnecting portion and said conduit arm portions extending downward outside said receptacle and communicating with said connecting portion through said open- E- 6. A sludge removal apparatus for reconditioning and recirculating coolant liquid for machine tools. comprising a receptacle having side and end walls connected by downwardly sloping bottom walls and having an inlet for sludge-contaminated coolant liquid, said bottom walls converging at their lower ends and terminating in an open-topped trough open at each end, tubular conveyor tubes connected to the trough and extending obliquely upward to the upper portion of saidreceptacle, a support mounted at the free ends of said conveyor tubes, a sprocket joumaled on said support, a motor carried by said support and drivingly connected to said sprocket, an endless conveyor connected to said sprocket and pass ing through said conveyor tubes into said trough, and a pump in communication with said receptacle at a location remote from said coolant liquid inlet and the trough for circulating said liquid to the machine tool.

-7. A sludge removal apparatus for reconditioning and recirculating coolant liquid for-machine tools, comprising a receptacle having side and end walls connected by downwardly sloping bottom walls and having an inlet for sludge-contaminated coolant liquid, said bottom-walls. converging at their lower ends and terminating in an open-topped trough open at each end, tubular conveyor tubes connected to the trough and extending obliquely upward to the upper portion or said receptacle, a support mounted at the free ends of said conveyor tubes, a sprocket journaled on said support, a motor carried by said support and drivingly connected to saidsprocket, an endless conveyor connected to said sprocket and passing through said conveyor tubes into said trough, and a pump in communication with said receptacle at a location remote from said coolant liquidinlet and the trough for circulating said liquid to the machine tool, said conveyor having spaced apart flight members adapted to remove sediment from said trough and convey the same to a point remote from the receptacle.

8. A sludge removal apparatus for reconditioning and recirculating coolant liquid for machine tools, comprising a receptacle having side and end walls connected by downwardly slopin bottom walls and having an inlet for sludge-contaminated coolant liquid, said bottom walls converging at their lower ends and terminating in an opentopped trough open at each end, tubular conveyor tubes connected to the trough and extending obliquely upward to the upper portion of said receptacle, a support mounted at the free ends of said. conveyor tubes, a sprocket journaled on said support, a motor carried by said support and convey the same to a point oi! discharge remote drivingly connected to said sprocket, an endless conveyor connected to said sprocket and passing through said conveyor tubes into said trough, and a pump in communication with said receptacle at a location remote from said coolant liquid inlet and the trough for circulating said liquid to the machine tool, said conveyor includ ing an endless chain having disc shaped conveyor,

flights secured thereto adapted to remove sediment from said trough and convey the same to a point exterior of said receptacle.

9. A sludge removal apparatus for reconditioning and recirculating coolant liquid for machine tools, comprising a receptacle having side and end walls connected by downwardly sloping bot-' tom walls and having an inlet for sludge-contaminated coolant liquid, said bottom walls converging at their lower ends and terminating in an open-topped trough open at each end, tubular conveyor tubes connected to the trough and extending obliquely upward to the upper portion of said receptacle, a support mounted at the free ends of said conveyor tubes, a sprocket jour- I naled on said support, a motor carried by said support and drivingly connected to said sprocket, an endless conveyor connected to. said sprocket and passing through said conveyor tubes into said trough, and a pump in communication with said receptacle at a location remote from said coolant liquid inlet and the trough for circulating from said receptacle.-

10. A sludge removal apparatus for reconditioning and recirculating coolant liquid for machine tools, comprising a receptacle having side and end walls connected by downwardly sloping bottom walls and having an inlet for sludgecontaminated coolant liquid, said bottom walls converging at their lower ends and terminating in an open-topped trough open at each end, tu-

bular conveyor tubes connected to the trough and extending obliquely upward to the upper portion of said receptacle, a, support mounted at the free ends of said conveyor tubes, a sprocket journaled on said support, a motor carried by said support and drivingly connected to said sprocket, an endless conveyor connected to said sprocket and passing through said conveyor tubes into said trough,

and,a pump in communication with said receptacle at a location remote from said coolant liquid inlet and the trough for circulating said liquid to the machine tool, at least one of said conveyor tubes having its free end flared outwardly to prevent pumping of the liquid by said conveyor.

11. A sludge removal apparatus for reconditioning and recirculating coolant liquid for machine tools, comprising a receptacle having side and end walls connected by downwardly sloping bottom Walls and having an inlet for sludge-contaminated coolant liquid, said bottom walls converging at their lower ends and terminating in an open-topped trough open at each end, tubular conveyor tubes connected, to the trough and extending obliquely upward to the upper portion of said receptacle, a support mounted at the free ends of said conveyor tubes, a sprocket journaled on said support, a motor carried by said support and drivingly connected to said sprocket, an endless conveyor connected to said sprocket and passing through said conveyor tubes into saidtrough, and a pump in communication with said receptacle at a location remote from said coolant liquid inlet and the trough for circulating said liquid to the machine tool, said receptaclehaving partition walls to cause liquid fed to said receptacle to follow a sinuous path directly above said trough. 7

12. A sludge removal apparatus for reconditioning and recirculating coolant liquid for machine tools, comprising a receptacle having side and end walls connected by downwardly sloping bottom walls and having an inlet for sludge-contaminated coolant liquid, said bottom walls converging at their lower ends and terminating in an open-topped trough open at each end, tubular conveyor tubes connected to the trough and extending obliquely upward to the upper portion ant liquid irom said machine tool and direct the said support, amotor carried by same downwardly into the vicinity of said trough.

13. A sludge removal apparatus for reconditioning and recirculating coolant liquid for machine tools, comprising a receptacle having side and end walls connected by downwardly sloping bottom walls and having an inlet jor. sludge-contaminated coolant liquid, said bottom walls converging at their lower ends and terminating in an opentopped trough open at each end, tubular conveyor tubes connected to the trough and extending obliquely upward to the upper portion or said receptacle, a support mounted at the free ends of said conveyor tubes, a sprocket journaled on said support and drivingly connected to said sprocket, an endless conveyorconnected to said sprocket and passing through said conveyor tubes into said trough, and a pump in communication with said receptacle at a location remote from said coolant liquid inlet and the trough for circulating said liquid to the machine tool, a partition in said receptacle separating said circulating pump from the remainder of said receptacle and a motor drive mechanism on the top of the receptacle above said pump for driving the same.

14. A sludge removal apparatus .for reconditioning and recirculating coolant liquid for machine tools, comprising a receptacle having side and end walls connected by downwardly sloping bottom walls and having an inlet for sludge-contaminated coolant liquid, said bottom walls converging at their lower ends and terminating in an open-topped trough open at each end, tubular conveyor tubes connected to the trough and extending obliquely upward to the upper portion of said receptacle, a support mounted at the tree ends of said conveyor tubes, 9, sprocket journ'aled on said support, a motor carried by said support and drivingly connected to said sprocket, -an endless conveyor connected to said sprocket and passing through said conveyor tubes 12 into said trough, and a pump in communication with said receptacle at a location remote from said coolant liquid inlet and the trough for circulating said liquid to the machine tool, said receptacle having in its upper portion at one side thereof a foam removal opening whereby to facilitate the removal of foam from the receptacle.

HENRY W. -HAPMAN.

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

UNITED STATES PATENTS Number Name Date 233,623 Imhorst Oct. 26, 1880 719,406 Wolfe Jan. 27, 1903 765,802 Wise July 26, 1904 801,204 Baum Oct. 10, 1905 876,713 Harden Jan. 14, 1908 1,209,654 Anderson Dec. 26, 1916 1,404,873 McGee Jan. 31, 1922 1,422,514 Arbuckle July 11, 1922 1,778,389 Hund Oct. 14, 1930 1,802,847 Btolte Apr. 28, 1931 1,928,036. Soderberg Sept. 26, 1933 1,991,667 Goldberg Feb. 19, 1935 2,128,569 Velz Aug. 30, 1938 2,139,096 Piquerez Dec. 6, 1938 2,140,289 Hurtt et al. Dec. 13, 1938 2,163,452 Schmieg June 20, 1939 2,244,442 Blauvelt --June 3, 1941 2,273,438 Entwistle et al. Feb, 17, 1942 2,291,641 Lemmon Aug. 4, 1942 2,318,524 Read May 4, 1943 2,323,223 Johnson June 29, 1943 2,378,798 Schneible June 19, 1945 FOREIGN PATENTS Number Country Date 420,429 Great Britain Dec. 3, 1934

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