US2714349A - Apparatus for making filtermass cakes - Google Patents

Description

Aug. 2, 1955 H. s. JOHNSTON 2,714,349

APPARATUS FOR MAKING FILTERMASS CAKES Filed NOV. 50, 1950 5 L75 ]z (Lg- 3 I YY\\ K Zia INVENTOR. /70m/d,1. 70fii2 riwa /2/Is 7 TOR/Vi United States Patent Ofiice 2,714,349 Patented Aug. 2, 1955 APPARATUS FOR MAKING FILTERMASS CAKES Harold S. Johnston, Waupaca, Wis., assignor, by mesne assignments, to The Pfaudler Co., Rochester, N. Y., a corporation of New York Application November 30, 1950, Serial No. 198,278

1 Claim. (Cl. 100-73) This invention relates to methods and means for making filtermass cakes.

The object of the invention is to make pads or cakes of filtermass, used in the various filtermass pulp filters, such as the Enzinger, Klein, Kiefer, etc. of a more uniform density than heretofore possible.

A further object is to make such cakes under better working conditions, and by'machine, without the hand of man touching the pulp. The present types of manufacture require the use of the hands in the attempted leveling or evening of the pulp, which at the best does not provide a uniform texture of the finished cake.

The invention consists of an improved method of making filter cakes, which consists in subjecting a predetermined amount of pulp corresponding in fiber content to the fiber content of the desired cake, to an atmospheric pressure diiferential while passing it through a partial desiccation or dehydration, and then compressing the residue to substantially complete water elimination corresponding to that of the known filtermass cake content, without the hand of man mixing the pulp during such cake formation, whereby a cake of uniform fiber distribution is obtained, homogeneous throughout, and in fiber symmetry.

The invention also contemplates an improved machine, wherein the cake is made under substantially automatic conditions, thus avoiding the use of the hands of the operators, and comprises, essentially a cylinder or mold to hold the required amount of pulp in 2 to 3% water suspension, to correspond to a filtermass cake of the standard size or any special size as may be specified, a screen below the pulp contents, and a means below the screen to carry away the free water descending from the screen, said means providing a minus pressure below the screen (otherwise generally called a partial vacuum), a ram or press member to press the pulp remaining after the free water has passed through the screen under the influence of the positive atmospheric pressure, the level of the pulp, and means removing the cylinder or mold from the formed cake to permit its removal from above the sieve.

For convenient operation, said apparatus is provided with measuring device to measure the desired amount of the charge of pulp to be treated in the cylinder or mold, and with means for repositioning the forming cylinder or mold after it has been removed from the sieve for the removal of the completed cake to enable the next cake to be made.

Also, a means is provided to remove excess water during the compression action, and lastly, perforated plate sup* ports are provided to prevent a bending or buckling of parts of perforated plates.

The invention will be further described hereinafter, an embodiment shown in the drawing, and the invention will be finally pointed out in the claim.

In the accompanying drawings,

Fig. 1 is a sectional view of an embodiment of the invention;

Fig. 2 is an enlarged section of part of Fig. 1, showing the cylinder or mold removed from the sieve, with the completely pressed filter mass cake ready to be removed from the sieve; and

Fig. 3 is a diagrammatic drawing showing the operation of the plus-minus pressures upon the pulp charge.

Similar characters of reference indicate corresponding parts throughout the various views.

Referring to the drawings, the filter cake forming sieve or perforated plate 1%) is supported on a hollow casing 11, to which a water discharge pipe 11a is secured, and which serves to draw of: or drain the water under reduced pressure or vacuum action. This reduced pressure may be obtained by any suitable means, as a vacuum pump device, etc. generally indicated by 12 and of known construction. The sieve is formed by a circular perforated plate which rests on preferably radial V-shaped supports 13 held by a ring 1311 supported by the casing 11.

Upon the sieve supporting casing 11 is placed a hollow cylindrical member or mold 15 of suitable height to contain a charge of pulp in solution. Guide members 15a serve to guide the mold when reciprocated. A height of 34" with an approximate diameter of 19 /2 inches is suitable for a 2-3% solution to produce a filter cake of desired standard depth. However, diameter, height and depth of cake may be varied, depending on the character of the cake desired. Important is the fiber contents in solution in the charge to correspond with the fiber contents in the completed cake, or reasonably so, depending on unavoidable leakages.

Within the mold is a piston acting plunger 16 of an outer diameter substantially equal to the inner diameter of the mold 15. As there may be some leakage between the plunger and mold the upper side of the plunger is provided with a concave circular or annulus portion 1'7 to collect the leakage liquid, and a hose or flexible pipe 18 is provided to remove by pumping or siphoning this surplus liquid. The plunger 16 is suitably operated for its downward compressing action, by means generally shown by 19, consisting preferably of the cylinder 20, piston 21, which acts also to again raise the plunger 16, after it has done its compression of the partially formed pulp into a cake. A constant pressure Water pump connected to pipes 29a and 20b to the cylinder 20, is used to assure uniform pressure on the cylinder ram or piston 21.

The mold 15 is raised from its sieve enclosing position (Fig. l), a suitable vertical distance to enable the completed cake 50 to be removed from the sieve 10, as seen in Fig. 2. Such means may be a hydraulic lifting cylinder 24, having pipes 24a and 2412, operating a lifting rod 25, connected with a projection 23 on the mold 15, to lift the mold 15 to enable the finished cake to be removed from the sieve and to reposition the mold on the sieve casing 11 for the next charge to be treated.

The mold 15 is charged with a charge of pulp in solu- 0 tion measured as to quantity in a device adapted to retain the amount of the charge. It is a tank or casing 31 having a baffie 32 forming two chambers 33 and 34 with a stock inlet at 35 and a stock outlet 36. The circuitous path of the stock around the lower end of the baflie 32 which is spaced from the bottom of the casing 31, by a space 32a assures a thorough mix, and the casing is emptied by a pipe 37 controlled by a valve 48 connected at said bottom and discharging at its outlet end 38 into the mold below the uppermost position of the plunger 16 and above the intended level of the charge 151) when in the mold. When the predetermined contents of the casing has been discharged into the mold 15, a bypass arrangement serves to conduct the stock of the supply tank 40 with a pipe 43a pumped by a pump 43 to the valve 4-5 back to the supply tank 4t) by a pipe 41. One way of bypassing is to provide three valves 44, 5 and 46, and a pipe 47 connected at each end to pipes 41 and 42. When valves 44 and 46 are closed and valve 45 is open, the pulp passes from pipe 42 through the connecting pipe 47 controlled by the open valve 45, and into pipe 41 and supply tank 40, and the stock is then circulated to keep it in satisfactory solution, while the tank 31 is being emptied. After the tank 31 has been discharged of its contents, valve 45 is closed, and valves 44 and 46 opened, andthen the stock is circulated through the measuring device 30, until the mold 15 is ready for its next charge. The valves are given as an illustration; simpler and more automatic means may be readily substituted.

The operation of the apparatus is asfollowsz.

The mold 15 is placed upon the sieve casing 11 to embrace the sieve andheld down tightly. Pulp of a measured amount coming from pipe end 38 substantially fills the mold to gauge b. The drain pipe 11a with a minus pressure with the positive pressure above the level of the liquid in the mold, causes the free liquid to descend through the sieve 10, leaving the fiber pulp on the sieve partially free from water. When the free water has been drained, the pulp is subjected to compression and the remaining water pressed out, until the cake of the usual consistency is formed. Then the mold 15 is raised to enable the cake to be removed by the rod 25.

The method contemplates the utilization of a ditferential pressure applied hydrostatically to both ends of an open ended cylinder, with the positive pressure above and the less or minus pressure below, whereby an even distribution of pressure throughout the cylindrical contents takes place, which is important in that it stabilizes the cake forming accumulation. if, for instance, at a certain point of the upper surface of the fiber mass an opening should form, then there would be a compensatory increase in velocity of movement of the fibers toward the opening, which would then quickly fill, and the rest of the upper surface would receive its even deposit or accumulation. Thereby, the improved method secures uniform density of the complete filter mass.

Recognizing the extreme variation across a pad, variations of 3040% in breweries of high standards of control, and noting also the extremely disagreeable conditions under which the pad is made, particularly in the winter months when the water at the mold is cold, the improved machine makes uniform pads, in such a manner as to completely eliminate all contact of hands of the operator when forming the cake, with much less labor involved. It overcomes the objections to the present equipment, in which the pulp in the final arrangement on the forming screen is distributed in a concentrated lumpy mass by the operator trying to get uniform distribution by pushing or working the lumpy material to approximate uniform density, uniform density being a physical impossibility with the practices heretofore known.

With the proposed press and totally contrary to the known practices, the stock is held in a suspended mass of dilute (.2%3%) concentration of water, the vacuum is applied at a point below the screen and without pressure from the ram. The stock is completely fluid as it forms in an even mass on and above the screen and continues to form evenly because the water carrying the stock flows to the weakest part or point of the pad, thus automatically forming a pad of extremely even density.

The measuring device is a specially designed two compartment tank through which the stock flows from the supply tank continuously except at the instant of discharge to the mold. The peculiar two compartment counterflow tank assures uniform measurement of the stock, without separation or channelling, when stock is not flowing to .the mold.

In the operation of this press the water from the mold is held completely within the apparatus itself and none 4 reaches the floor or working area of the room. The working conditions are much improved and the operator needs no rubber clothing such as boots, apron, and gloves as are necessary in the operation of present equipment.

In breweries where several men are needed to supply the required number of cakes per day, a very marked labor saving results.

One man can operate this equipment and produce one cake per minute, by continuous operation.

A summary of the improved results may be stated as follows:

1. Uniform cakes, (a) greater capacity; (b) uniform flow; (c) less line pressure drop over same period of time; (d) sharper filtration due to lack of weak spots in the pad;

2. Improved working conditions, (a) a drier press room; (b) less labor;

3. Labor saving and speed of operation.

I wish it to be understood that I do notdesire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:

In an apparatus for. making filtermass. cakes, the combination of a hollow cylindrical casing, means providing a partial vacuum in said casing, a sieve above said casing, the entire lower side of which is exposed to the hollow space of said casing, a cylindrical hollow mold above the sieve resting on said sieve in one of its positions and aligned with. said casing to provide a liquid tight joint therewith, meansv vertically moving said mold, a piston in said mold, means reciprocating said piston the length of its stroke within said mold limited to a stroke of fixed length having an upper limit and a lower limit, saidmold having an orifice for supplying a charge of pulp below the piston when the piston is at its upper limit, and means including a measuring container of at least the same capacity as said charge to said mold, a discharge pipe connecting said measuring container with. said. charge inlet. orifice, a, pulp supply tank, a first pipe from said tank to the measuring container, a second pipe from, said measuring container to said tank, a circulating pump. for said first pipe, means connecting saidfirst and second pipes to each other for bypassing said pulp from said measuring tank when said measuring device is emptying into said. mold, whereby when said charge of. pulp is in the cylinder mold the water of the pulp first drains off, then the pulp is compressed on its upper side to a cake, while a suction acts on the lower side of. the cake withdrawing the water through said sieve, whereupon said mold is raised by said moving, means. to discharge said cake, the mold returned to said sieve, the piston raised above the charge inlet orifice forpanew charge, the pulp being at all times in circulation, both when in said measuring container and when by-passed.

References Cited in the file of this patent UNITED STATES PATENTS 772,472 Neill Oct. 18, 1904 906,044 Malcolm Dec. 8, 1908 1,426,163 Emrick Aug. 15, 1922 1,527,200 Louisot Feb. 24, 1925 1,676,798 OBrien July 10, 1928 1,861,849 Frobisher June 7, 1932 1,983,553 Manson Dec. 11, 1934 2,070,040 Chapman Feb. 9, 1937' FOREIGN PATENTS 680,344 France Apr. 28, 1930

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