US3033762A

US3033762A - Straining tank

Info

Publication number: US3033762A
Application number: US853330A
Authority: US
Inventors: Frank H Schwaiger; Robert C Gadsby; Schwaiger Joseph
Original assignee: Anheuser Busch Companies LLC
Current assignee: Anheuser Busch Companies LLC
Priority date: 1959-11-16
Filing date: 1959-11-16
Publication date: 1962-05-08
Anticipated expiration: 1979-05-08

Description

May 8, 1962 Filed Nov. 16, 1959 F. H. SCHWAIGER ET AL STRAINING TANK 4 Sheets-Sheet 1 R770 xA/f ys,

May 8, 1962 F. H. SCHWAIGER ET AL 3,033,762

STRAINING TANK 4 Sheets-Sheet 2 Filed Nov. 16, 1959 May 8, 1962 F. H. scHwAlGl-:R ET AL 3,033,762

STRAINING TANK 4 Sheets-Sheet 3 Filed Nov. 16, 1959 F. H. SCHWAIGER ET AL STRAINING TANK 4 Sheets-Sheet 4 May 8, 1962 Filed Nov. 16, 1959 FIG] 3,633,762 STRAWING TANK Frmk H. Schwaiger', La Ene, Robert C. Gadshy, St..Louis County, and .loseph Schwaiger, Aton, Mo., assigner-s to Anheuser-Busch, incorporated, St. Louis, Mo., a corporation of lvissonri Filed Nov. 16, 1959, Ser. No. 853,338 6 Claims. (Cl. 195-135) This invention relates to an improved straining tank or grain extractor or lauter tub, and more particularly to an improvement in an existing kind of lauter tub presently in widespread use in the brewing industry to remove extract from brewers grains.

This invention relates to an improvement in existing lauter tubs having agitators therein which increases the etliciency or reduces the draw-o time to about twothirds of the time previously required. This is important because the lautering step in the brewing process has in the past been one of the slowest and one of the bottlenecks in the production of beer. In' other words, in' the usual brewing operation today, the capacity of the step which uses lauter tubs or straining tanks largely determines the capacity of the brewery.'

In our co-pending applications Serial No. 724,561, tiled March 28, 1958, now Patent No. 2,916,421, granted December S, 1959, and Serial No. 7 88,689, tiled January 23, 1959, now Patent No. 2,936,236, granted May 10, 1959, We disclose a new type of straining tank and method, which completely replaces lauter tubs of earlier designs having agitators therein. The straining tank described in said co-pending application is especially useful in new installations, such `as when new breweries are built or when new lauter tubs are required in existing facilities.

The purpose of the present invention is to improve the operation and/ or efliciency of existing lauter tubs which are still in good condition and which cannot be economically replaced. At present, the conventional type lauter tub used in the brewing industry is a relatively large `and expensive piece of equipment. ltsl diameter is usually from about 12 feet to 27 feet and it has a heavy and expensive power driven rake or lauter machine which rotates therein to agitate and loosen the grains. This is sometimes referred to as an agitator. Typical devices of this Sort are shown in United States Patent Nos. 2,014,- 945, 2,150,009, 2,262,863, and others.

One of the principal objects oi the present invention is to modify and improve existing lauter tubs to materially increase their capacity in the brewing operation or reduce the time required for the straining operation. Another object is to reduce the straining time by as much as one-third by modifying the existing lauter tub in a relatively simple and inexpensive manner. Another object is to provide a lauter tub in which the pull of the wort through the thick grain bed is relatively easy since the grains do not tend to compact as much as in conventional lauter tubs. Another object is to maintain the grain bed in a loose condition so that the grains near the false bottom are relatively loose. Another object is to provide for greatly improved operation with only a minor and relatively inexpensive change in the existing equipment.

Still another object is to provide an additional drawoif level over that heretofore usedin conventional lauter tubs in order to improve the efhciency of the operation and maintain excellent quality at the same time.

These and other objects and advantages Vwill become apparent hereinafter.

This invention is embodied in a lauter tub of the existing and conventional type having an agitator therein, said lauter tub having a slotted ring tube inwardly ofthe vertical lauter tub wall, the top of said tube positioned slight*- ice ly below the top level of the grain bed; said slotted ring tube having draw-ott pipes leading to a header for controlling the low from said slotted ring tube, and a pipe from said header to` the grant, said grant also receiving wortV in the normal manner through pipes leading from the `false bottom through which much of the wort is drawn.

The invention is also embodied ina system for drawing oit the first wort from an upper point slightly below the top of the grain bed, continuing the draw-off from said upper point, and thereafter drawing od the wort from boththe upperpoint and through the falsebottom in the usual manner, thereby reducing the draw-oli time substantially.

This invention also consists in the parts and in the arrangements and combination of parts hereinafter described and claimed. In the accompanying drawings which` form part of the specification and wherein like numerals and symbols refer to like parts wherever they occur:

FIG. 1 is a side elevational View, partly in section, illustrating a lauter tank embodying the present invention,

FIG. 2 is a horizontal cross-sectional view taken along the line 2,-2 ofFlG. 1,

FIG. 3 is a bottom plan View of the draw-off tubes and control valves which are located beneath the lauter tank,

FIG. 4 is an enlargedvertical cross-sectional view taken along the line 4-4' in FIG; 2 showing the slotted ring tube,

FlG. Sis-an enlarged fragmentary top plan view of a portion of said slotted ring tube,

FIG. 6 is anY enlarged view of one of the removable sections of said slotted ring tube, and

FIG. 7 is a front elevational view of the controls for controlling the pull and the draw-oit of the wort from the false bottom and from the slotted ring tube.

Referring now to the drawings in detail, which show a lauter tub about 27 feet in diameter, it will be seen that the embodiment of the invention which has been illustrated is provided in a straining tank or lauter tub 1 having ya cover member 2 and a bottom member 3 with a cylindrical wall 4 therebetween. The cover member 2 is provided with a vent stack 5 `and openings or manholes 6. The cylindrical wall 4 is insulated yas indicated by the reference numeral 7. The bottom member 3 is suitably supported, as-at 8, `and is provided with a plurality of spaced draw-olf connections 9 which are connected by suitable piping 10.

The straining tank- 1 is provided with a rotating mechanism or agitator 11 which subjects the batch of grain, not shown, in the tank to a momentary separation. The lauter rotating mechanism 11 comprises a vertical shaft 12 which extends upwardly from the bottom memlber 3 along the central axis of the straining tank 1. The shaft 12 is operatively connected to a hydraulic cylinder 13 which is operated by a rotating shaft 14 extending upwardly from a gear unit 15 which is actuated either by a low-speed drive shaft 16 vor a high-speed drive shaft 17 driven by prime movers not shown. The low-speed prime mover preferably causes the rotating shaft 1 4 to" rotate about 0.25 rpm., whereas the variable speed larger prime mover causes the shaft 14 to rotate between 4 to 10 r.p.m.

Two agitating arms 18 extend radially outwardly from said vertical shaft 12 and each arm 18 is provided with a plurality of rotatable or adjustable spaced knife members 19. vThese spaced knife members 19 are adjusted by suitable control means Ztl mounted on said arms 18. AV

substantially horizontal inner or false bottom 21 is provided below the bottom edges of the knife members 19 and above the bottom member 3. The bottom member 3 is shown with valleys or sloping portions to direct the How of wort, but the bottom may be of any suitable design. The inner bottom 2,1 is provided with openings or slots 22 over its entire surface.

Suitable grain discharge slide gates 23 are provided in the bottom member 3 for removing the grain from the lauter tub 1. The inner or false bottom 21 is preferably formed from la plurality of perforated false bottom sections 24, each supported by upstanding pedestals and locking devices which maintain the inner bottom 21 and bottom member 3 in spaced relation. The false bottom 21 is also provided with a grain discharge slide gate which registers with the slide gate 23. A suitable grain inlet 26 is positioned in the wall 4 of the tank.

The straining tank 1 is provided with a sparge line 27 which extends vertically upwardly along the cylindrical Wall 4 and enters the lauter tank 1 through an opening 28 in the cover member 2. The sparge line 27 feeds two `

circular headers

29 and 30 each having a plurality of holes or openings 31 positioned in the upper portion of the lauter tank 1 for washing the rotating mechanism 11 as well as the inside surface of the lauter tank 1 and includes spraying and supplying Water to grain bed for purpose of extracting wort.

The draw-off connections 9 have suitable draw-o tubes extending therefrom which lead to connections 32 which in turn lead to control valves 33. A separate control valve 33 is provided for each of the drawoff connections 32 and these valves are preferably positioned close together, as shown in FIG. 3.

By use of the three valves 33, the flow of the wort from the evenly spaced draw-oil? connections 9 can be controlled. These valves 33 can be regulated so that each draw-off connection 9 draws off the same amount of Wort. In the well known manner, the valves 33 can be controlled to properly deliver the Wort from each

pipe

10 and 32 through the line 34 to the grant 35. The line 34 is also provided with a slide valve 36 and suitable pipes for cold water Iand for sparge Water.

The structure described in detail in the last several paragraphs hasA beenrknown in the prior art and has given good results for many years. Our improvement which greatly improves the operation of the lautering step comprises adding'an additional draw-off means or slotted ring tube 40 at a critical position within the lauter tub 1. We have found that the draw-off time can be reduced from 140 minutes to 92 minutes in a typical vlauter tub having a diameter of about 27 feet simply by using the slotted ring tube 40 and piping hereinafter described.

In practice, We have found that the slotted ring tube 40 should preferably be ofthe cross-section shown in FIG. 4. A This shape is Y generally pointed at the top 4l `and has two sides 42 Yand 43 which curve gradually into a cur/ed bottom portion d4. This shape tends to prevent grains from accumulating on the tube 40. The vertical -height ofthe ring tube 40 in a lauter tub about 27 feet 4in' diameter from therpoint 41 to the lowermost portion of the curvedbottom 44 is` approximately 5 inches and its greatest horizontal width between the side wall 43 and 'the remote joining of the side .wall 42 and curved bottom 44 is about 5 inches.V The gradual curves and absence of sharp corners facilitate cleaning. The ring tube iti ,contains a pluralty of openings or slots 45 which are slightly staggered. These slots are approximately 1/2 inch long and 0.025-inch wide although holes of the same width may be used if desired. The 0.025 inch dimension `is critical for grains of the size normally used in a typical brewingV operation and should not be increased even as Amuch as 0.002 inch since such will allow undesired par- Aticles from the grains or husks to get into the wort draw-off system thereby causing the Wort to be cloudy or otherwise unsatisfactory. The preferred distance between the slots is about 1//s inch, although this distance can be varied within limits for maximum eiliciency.

The precise position of the ring tube 40 in the lauter tub 1 is critical for the most eliicient operation. We have found that the most important distance is the distance which the point 41 of the ring tube 40 is positioned below the top level of the grains in normal operation. This distance should preferably be about 2 inches although it can be varied between about one and three inches. Any further deviation outside of the one to three inches preferred range results in gradual but marked decreased eliiciency as the distance varies from the preferred 2 inches. However, there will be increased etliciency at almost any vertical distance which the ring tube 40 is placed in the upper half of the grain bed, as compared to a lauter tub having no ring tube 40 therein. We prefer to attach the ring tube 40 by suitable means, preferably Welded brackets directly to the cylindrical wall 4 so that there is a space S of about three inches between the cylindrical wall 4 and the closest portion of the generally vertical side wall 43 of the ring tube 40. This distance can be varied slightly within limits, but should not be increased so greatly as to interfere with the knife members 19 which are required for suitable separation and agitation of the grain bed in a lauter tub of the conventional type. With this preferred distance, only the outer knife blade 19 needs to be removed from the arm 18 to provide the necessary outer annular space 47 for the ring tube dit. With new lauter tubs of this design, the arm 18 can initially be made shorter so as to provide the necessary space 47 between the outermost knife blade 19 and the cylindrical wall 4.

Since cleanliness is so important to proper brewing operations, several removable sections 48 are provided in the slotted ring tube 40. These sections 48 have suitable fastening means 49 and Sil thereon for engaging and disengaging the ends of the permanently mounted sections 51 of the ring tube 40. Each removable section 48 can be cleaned separately and each permanent section 51 can be cleaned by inserting a hose or a cleaning rod through its open ends which are exposed when a removable section 48 is disengaged. The ring tube 40 is generally concentric with the cylindrical wall 4 and substantially horizontal.

The ring tube 40 has several draw-off connections 52 spaced equally apart, each provided with a shut-off valve 52a. The connections 52 lead to draw-off tubes 53 and pipes 54 having control valves 55 therein. Each drawoff tube 53 is preferably 2 inches in diameter and leads toV a 3 inch diameter connecting pipe 54 which is connected to a larger pipe 56 which leads to an upstanding header 57 whose upper portion extends at least to the level of the point M, The valves 55 connected to the tubes 53 and pipes 54, which have hydrometers connected therein, are necessary for uniformity of extract. As shown, the four draw-olf connections 52 are spaced ninety degrees apart and the tubes 53 on the left, as shown in FIG. 3, are the same length as their opposite tubes 53 on the right. `That is, the two tubes 53 which lead to a common Vjunction with each of the two pipes 54 should preferably be of equal length to give proper ilow and pull.

lThe header 57 has a sight tube 58 thereon for determining the head or liquid level within the header 57. A pipe 59 with a control valve 60 therein connects the header 57 with the grant 35. This piping is best shown in `FIGS. 3 and 7, the Vformer of which shows a bottom elevational view of the piping leading to the grant.

ring tube in a loose condition. In practice, the liquid level in the header is maintained slightly higher than the level of the ring tube de and the high point 63 of the gooseneck 64 connected with the false bottom 21 is positioned yslightly above the level of said false bottom 21. The valve 36 can be closed or opened to allow wort to pass through the gooseneck 64 or the pipe 65 which leads into the grant 35 near the bottom thereof.

A sight tube 66 is provided to indicate the height of the liquid in the tub 1, and another sight tube 67 is provided to indicate the pull through the false bottom 2l just as the sight tube 5S indicates the pull through the ring tube 4i?. The

sight tubes

58, 66, and 67 are preferably positioned close together so they can be read with ease. Each is provided with a drain at the bottom with ya valve therein. The sight tube 58 should also have a sight tube, not shown, which indicates the level of the liquid in the tub, associated with it for comparison purposes, just as the sight tube 67 has the tu-be 66. If desired, this sight tube may be a take off from the tube 66. Such a tube can be eliminated, however, if the

sight tubes

58, 66, and 67 are closely positioned.

The operation of a lauter tub embodying the present invention is the same yas the operation of a conventional lauter tub without the slotted ring tube 40 as are its plping, normal maintenance, loading and unloading of the grains, basic cleaning, and other matters except as follows. With all parts yabsolutely clean and controls in their proper position, the lauter tub is lled with mash or brewers grains with -suliicient water. This is pumped in through the inlet until the top level of Said mixture reaches about to the point M in the tub. The inlet 26 is then closed. This requires about l0 minutes. After a proper period during the claritlcation and rest, hereinafter described, the grains settle to a level at the point G which is just below the arm 18 and about 2 inches above the top 41 of the ring tube 4%.

The

valves

33 and 36 are then opened to clarify the wort in the regular manner through the false bottom 2l. This requires about l0 minutes, but after the tirst 7 minutes the valves 55' and 6G from the ring tube 40 are opened so that clarification also takes place through the ring tube 49. Thus, clariiication of the wort requires about l() minutes, the iirst 7 minutes of which results from clarification only through the false bottom 2l and the last 3 minutes of which takes place through the false bottom 2.1 and through the ring tube 40. After the wort indicates that clariiication has started, the grains are aliowed to rest for a proper time, usually 2O minutes, during which time the agitator rotates slowly to keep the grains separated.

The false bottom 21 and the ring tube 40 are then tapped at the same time by opening the valves 36 and 61) to draw-oit the iirst wort. The rst wort continues to be drawn oil `for a short time, usually 30-40 minutes, and sparging `thereafter -begins in the regular way after the valve 36 has been closed to direct the wort through the gooseneck 64. Sparging is accomplished by opening Ia valve to allow water tofenter the grain bed through the pipes 29 and '39 as wort -is--being extracted through the

pipes

32 and 54. Drawing o of the wort continues through the false bottom 2l and the ring tube 44) until such time as the-extract at the ring tube level is reduced to about 2.0 Balling, after which the valve 60 is closed to shut ott the iiow from the ring tube 40. VThe valves 33 and 5S are used to regulate the llow. The draw-off continues through the false bottom 2l until the wort is reduced to about 1.0 to 2.0 Balling at which time the draw-oil is discontinued. The grain traps 23 and 25 are then opened and all of the grains are removed.

With the grain traps Z4 and 25 still open most of the time, the tank is flushed and cleaned. This is accomplished by opening the water valves and allowing water to surge through the

circular headers

29 and 36. After a limited number or" brews, the tub is completely hosed and cleaned making certain that the walls d, the ring tube 49, the false bottom 2l, and all other portions are clean. This is done in the usual manner.

In practice, we have found that the ring tube 49 can be used to draw-off the `lirst Wort completely and and can be used for extraction during the sparging period for about one-third of the time required for sparging. This decreases the time required for theentire step by as much as one-third. In actual production with a 27 foot diameter tub wherein the mash has a depth of about 32 to 36 inches and the grain bed `or bed of solids is about l2 to 14 inches high, we have been able to reduce the total time of the lautering step from about minutes to 92 minutes. It is believed that this great increase in eiiiciency results from the fact that the pull through the false vbottom is lessened so that the grains at the false bottom 21 yare maintained in a loose condition and are less tight and the entire grain bed remains relatively loose, as compared to a conventional lauter tub without the ring tube and its piping. This relatively loose condition remains even after the ring tube is shut oil.

In practice, we have taken as much as half of the wort from the ring tube 4t), the remaining half coming through the false bottom 2l. This reduces the amount of wort or liquid moving downwardly through the entire grain bed. This is important since a so-called upper dough or coagulated protein forms on the top of the grain bed in normal operation. The upper dough oats readily and generally is pulled into the grain bed toward the false bottom 'by the action of the agitator blades where it gathers andfurther tends to restrict the flow. `Our ring tube 40 reduces the movement of the upper dough due to a lesser volume of wort being drawn through the false bottom. Even after the ring tube is shut oil in our operation, the general condition of the grain bed for the remaining portion of the step remains in a relatively loose condition.

ln a conventional tub, the great pull of the wort through the grain bed tends to compact the grains and slows Vstraining with the result that the operator then moves the controls to increase the pull to obtain wort at a faster rate which in turn tends to compact the grains more tightly. The ring tube 40 serves as an additional drawoff means located at a critical point so as to receive wort with a high Balling and to serve as a relief against compacting of the grains. lf the operator Wishes to drawol wort as quickly as possible, he may control the ow through the ring tube 40 as well as the false bottom 21 thereby not increasing the Vpull through the false bottom 21 with the resulting endless cycle of compacting the grains, increasing the pull, which in turn compacts the grains further.

It will be seen that the invention comprises a lauter tub having a slotted ring tube critically positioned with in the tank in a manner which does not interfere with the preferred agitation of the grain bed and through which a portion of the wort can be drawn to reduce the pull through the false bottom thereby tending to improve the loose characteristic of the grain bed and reduce the total time forextraction.

The distances referred to herein are preferable for max* imum eciency but can be varied within limits with lauter tubs of different sizes. Eiiiciency drops and moves toward the normal eliiciency of a conventional tub as one moves away from the preferred distances used for a particular size of conventional lauter tub.

This invention is intended to cover all changes and `modiiicationso't the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

What we claim is:

l. A straining tank having a bottom, a cover positioned above said bottom with a tubular wall there etween, 'said tank having an inlet therein for receiving granular material which forms a bedof solids and an outlet Vin the bottom thereof for removing said material, means for directing water into said tank, said tank having an agitator therein which moves through said granular material, said bottom having a slotted false bottom positioned thereabove through which wort may drain, a slotted ring tube positioned above said false bottom and below the top level of said bed of solids and being positioned substantially in the upper half thereof and inwardly of said tubular wall, and draw-olf pipes from said ring tube and said bottom below said false bottom for controlling the ilow of wort from said tank.

2. A straining tank having a bottom, a cover positioned above said bottom with a tubularwall therebetween, said tank having an inlet therein for receiving granular material which forms a bed of solids and an outlet in the bottom thereof for removing said material, means for directing water into said tank, said tank having an agitator therein which moves through said granular material, said bottom having a slotted false bottom positioned thereabove through which wort may drain, a slotted ring tube positioned above said false bottom and slightly below the top level of said bed of solids and being positioned substantially in the upper half thereof, said ring tube being positioned adjacent to and slightly inwardly of said tubular wall and supported thereby, and draw-oil pipes from said ring tube and said bottom below said false bottom with valves therein for controlling the flow of wort from said tank.

3. A straining tank comprising an upright tubular body portion with a bottom and false bottom adjacent to the bottom portion thereof and a cover adjacent to the top portion thereof, said tank having an agitator rotatably mounted therein at a level between said false bottom and said cover, a slotted ring tube positioned between said false bottom and said cover, said slotted ring tube positioned inwardly of and adjacent to said tubular body portion andin circumscribing relation to said agitator, an inlet and an outlet in said tank for receiving and removing granular material, an inlet for directing water into said tank, and draw-Dif pipes from said bottom below said false bottom and ring tube for drawing-off wort from said tank.

4. A straining tank comprising an upright cylindrical body portion with a bottom and slotted false bottom adjacent to the bottom portion thereof and a cover adjacent to the top portion thereof, said tank having an agitator rotatably mounted therein at a level between said false bottom and said cover adjacent to said false bottom, a slotted ring tube positioned between said false bottom and said cover, said slotted ring tube secured to said tubular body portion in circumscribing relation to said agitator, an inlet and an outlet in said tank for receiving and removing granular material, an inlet for directing Water into said tank, said last mentioned inlet being positionedhigher than said slotted ring tube, draw-oil pipes from said bottom below said false bottom and ring tube for drawing-off wort from said tank, said draw-olf pipes from said ring tube connected to a vertical header with a control valve connected therewith for regulating the flow from said ring tube.

5. A straining tank ,comprising an upright cylindrical wall having a bottom andra false bottom adjacent to the bottom portion thereof and a cover adjacent to the top portion thereof, saidtank having an inlet therein for receiving granular material which forms a bed of solids and an outlet in the bottom therefor for removing said grains, an inlet for directing water into said tank, said tank having an agitator therein which moves through said grains, said agitator comprising a laterally extending arm with depending blades thereon, said arm positioned above the normal top level of said grains and said blades extending into said grains below the top level thereof, said false bottom having slots therein through which wort may drain, a slotted ring tube positioned in said tank below the top level of said bed of solids and being positioned substantially in the upper half thereof, said ring tube positioned inwardly of said cylindrical wall and circumferentially outwardly from said blades, draw-olf pipes from said bottom below said false bottom with valves therein for drawing-olf and controlling the ow of wort through said false bottom, draw-oil pipes from said ring tube with valves therein for drawing-off and controlling the ow of wort from said ring tube, said latter mentioned draw-olf pipes connected to an upstanding header having a control valve connected therewith for regulating the ilow through said ring tube, said header having a height at least as high as the level to which the incoming granular material and water are lilled initially in the tank.

6. A straining tank comprising an upright cylindrical wall having a bottom and a false bottom adjacent to the bottom portion thereof and a cover adjacent to the top portion thereof, said tank having an inlet therein for receiving granular material which forms a bed of solids and an outlet in the bottom thereof for removing said material, an inlet for directing water into said tank, said tank having an agitator therein which moves through said grains, said agitator comprising a laterally extending arm with depending blades thereon, said arm positioned above the normal top level of said grains and said blades eX- tending into said grains below the top level thereof, said false bottom having slots therein through which wort may drain, a slotted ring tube positioned in said tank below the top level of said bed of solids and being positioned substantially in the upper half thereof, said ring tube secured to said cylindrical Wall circumferentially outwardlyl from said blades, said ring tube positioned below the level of said inlet for directing water into said tank, and draw-off pipesA from said bottom below said false bottom with valves therein for drawing-oit and controlling the ilow of wort through said false bottom, draw-off pipes from said ring tube with valves therein for drawing-off and controlling the flow of Wort from said ring tube, said latter mentioned draw-oli pipes connected to an upstanding header having a control valve connected therewith for regulating the flow through said ring tube, said header having a height at least as high as the level to which the incoming granular material and water are filled initially in the tank.

References Cited in the le of this patent UNITED STATES PATENTS 603,587 Dorn May 3, 1898 804,979 Rach Nov. 2l, 1905 1,010,244 Fairlield Nov. 28, 1911 1,041,533 Wagner Oct. 15, 1912 1,272,458 Keller July 16, 1918 1,914,850 Foster June 20, 1933 2,262,863 Schock Nov. 18, 1941 2,604,443 Fipps July 22, 1952 2,782,013 Dittrich Feb. 19, 1957 2,852,369 Eyolfson Sept. 16, 1958 2,916,421 Schwaiger et al. Dec. 8, 1959 FOREIGN PATENTS 13,819 Great Britain Nov. 12, 1885

Claims

1. A STRAINING TANK HAVING A BOTTOM, A COVER POSISTIONED ABOVE SAID BOTTOM WITH A TUBULAR WALL THEREBETWEEN, SAID TANK HAVING AN INLET THEREIN FOR RECEIVING GRANULAR MATERIAL WHICH FORMS A BED OF SOLIDS AND AN OUTLET IN THE BOTTOM THEREOF FOR REMOVING SAID MATERIAL, MEANS FOR DIRECTING WATER INTO SAID TANK, SAID TANK HAVING AN AGITATOR THEREIN WHICH MOVES THROUGH SAID GRANULAR MATERIAL, SAID BOTTOM HAVING A SOTTED FALSE BOTTOM POSITIONED THEREABOVE THROUGH WHICH WORT MAY DRAIN, A SLOTTED RING TUBE POSITIONED ABOVE SAID FALSE BOTTOM AND BELOW THEA TOP LEVEL OF SAID BED OF SOLIDS AND BEING POSITIONED SUBSTANTIALLY IN THE UPPER HALF THEREOF AND INWARDLY OF SAID TUBULAR WALL, AND FRAW-OFF PIPES FROM SAID RING TUBE AND SAID BOTTOM BELOW SAID FALSE BOTTOM FOR CONTROLLING THE FLOW OF WORT FTOM SAID TANK.