US2340009A - Press - Google Patents

Description

Jan. 25, 1944. E. T. MEAKIN 2,340,009

PRESS Fil ed Oct. 14, 1940 2 Sheets-Sheet 1 INVENTOR. 06 44 7: Mmmw ATTORNEY L Jan. 25, 1944. E. T. MEA KIN 2,340,009

PRESS I Filed Oct. 14, 1940 2 Sheets-Sheet 2 INVENTOR. EDGAR 7-. ME'AK/N BYMQM I I ATTORNEY Patented Jan. 25, 1944 acrobat rnsss age: a. Me San Francisco, cam. Application October 1d, 1940, Serial No.361,045 '7 (Cl. loo-as) Claims.

My invention relates to presses, and more particularly to control means for presses of the screw type. .v

In presses adapted, for example, to the extrusion of juice or oil from fruits, seeds, fish or the like, as the case may be, most satisfactory and efficient operation, and consequently, a resuiting greater recovery, is realized within the region of a certain operating pressure within the extrusion chamber. What this pressure will be is determined in large measure by the kind and type of material to be operated on. Any factor which tends to load or lighten the load on the press will result in a departure from the best operating conditions within the extrusion chamber, even to the extent at times of causing lamming of the press. The pressure within the extrusion chamber must, as a consequence, shift outside of the relatively narrow range of eflicient operating pressures, to a value representing a lower recovery and, consequently, poorer efllciency. It is, therefore, desirable to maintain a substantially constant pressure within the extrusion chamber, in spite of any factors tending to upset this condition.

Prior attempts to solve this problem have not been entirely satisfactory, such attempts, for the most part, taking the form of manually controllable cone operating means for the solids discharge passage from the extrusion chamben. An operator, finding the machine-not operating properly, makes whatever manual adjustment be desires or thinks necessary to remedy the situation,

often discovering the condition too late to preclude upsetting the operating pressure or jamming of the press.

Among the objects of my invention are to provide a newly designed extrusion press-'-' (1) In which the operating pressure shall be maintained within relatively narrow limits, in spite of any factors tending to shift such pressure beyond these limits,

(2) In which any tendency for jamming to occur will bring about a rapid and complete release of the contents of the extrusion chamber, as a step toward restoring the machine to normal operation, 1

(3) In which the operating pressure will be maintained through hydraulic means,

(4) In which the proper operating conditions shall-be maintained automatically,

(5) In which pressure maintaining mean is provided that'is adjustable tomaintain different values of operating pressures, and

(6) In which thepressure regulating means is made automatically responsive to the load variations which the press during operation places upon its driving motor.

Additional objects of my invention will be brought out in the following description of the same taken in conjunction with the accompanying drawings wherein- Figure 1 is a sectional view in a vertical plane through a continuous type press with a preferred embodiment of my improved control system incorporated therein,

ferred embodiment, I provide a hydraulic control system which normally tends to urge the cone to closing position in the discharge passage from .the extrusion chamber, but which is rendered responsive to an overload on the press driving motor, for quickly retracting the cone to its extreme open position. If such overload value be selected which is indicative of a condition in the press extrusion chamber, conducive'to jamming of the press, then maximum opening of the solids passage'of the press will occur only under such extreme condition of operation, to preclude the development of dangerous pressureswithin the extrusion chamber and permit elimination from such chamber of the solid products tending to clog the same.

For conditions of less seriousness, developing in the press, which may have a tendency to fluctuate the pressure condition therein, lie system is provided with a relief valve which will operate to maintain a normal. pressure goondition, by permitting the cone to vary the discharge opening in accordance with such factors tending to alter the operating pressure.

For a more detailed description of my invention, reference will be made to the accompanying drawings wherein I have disclosed my'invention as appliedto a continuous screw type press for the extrusion of juices or oils from various products. r

This type of press, in generahcomprises an extrusion chamber l having at one end an inthe hydrautegrally formed hopper 3 for the introduction of the products to be pressed, while at the other end, the extrusion chamber is open for the discharge of the solid products remaining after the recovery of the juices or oils therefrom. The juices or oils are extruded through an intermediate portion of the extrusion chamber which is formedof heavy screening 5 reinforced by longitudinal ribs 6 and transverse ribs I. At its open end, the extrusion chamber is supported upon a standard 8.

The hopper end of the extrusion chamber enters a wall 9 of a gear housing II. and is afllxed thereto by suitable belts or the like. The gear housing, in turn, is supported on a standard or base l3, whereby the hopper end of the extrusion chamber will be maintained at a common level with the open end of the extrusionchamber.

this end of the screw shaft and the extrusion chamber constituting the discharge opening for the solid products of the press. The tapered shaft ll carries a spiral rib or thread 33 from the hopper end of the screw shaft toan inter mediate point along the screen 5, short of the discharge end of the extrusion chamber. This rib is of a height causing the same to practically A reach the wall surface of the extrusion chamber.

The screw I5 is mounted for rotation, at its driven end, by a shaft extension 25 supported in suitable bearings 21 and 29 at opposite sides of the gear housing. This shaft extension carries a drive gear 3| which is in mesh with a drivin pinion 33 fixed to the shaft 35 of a driving-motor S'i. Lubrication of the gear and pinion assembly is effected by an oil reservoir 39 at the bottom of the gear casing, and into which the gear 3| At its enlarged hollow end, the screw shaft I1 is provided with a shaft extension 4| passing out through the open end of the extrusion chamher. The end portion of this shaft extension is of reduced cross section. A U-shaped bracket 42 aflixed to the open end of the extrusion chamber carries a bearing 43' through which the reduced portion of the shaft extension passes and is joumalled.

In the operation of a press of this character, the product to be pressed'is placed in the hopper 3 and, due to the screw construction, such material is compressed to an increasingly higher degree, as the product is carried along by the screw I5 toward the discharge end oi the extrusion chamber. The juice or oil thus pressed from the product passes through the screen I of the extrusion chamber and is caught in a tank 45 positioned below the" extrusion chamber for the purpose. A suitable guard casing 48 may be placed around the extrusion chamber as aprotection.

It has been found that maximum recovery. and accordingly higher eiliciency of operation,

.may be expected in a press of this character.

when operating within a very narrow range of pressures, the particular range dependinlupon the type and quality ofthe product to be operated on. Many factors, however, tend to disturb such operating condition within the extrusion chamher, and as an example of this, it might be pointed out that any variation in moisture content, or physical characteristic, or degree of ripeness in the product to be pressed, may tend to vary the load on the press and upset the desired pressure conditions therein. Such disturbing factors can be compensated for and eliminated in accordance with my invention, by varying the effective size of the discharge passage to relieve any tendency for such avariation in' pressure condition within the extrusion chamber to develop; and under extreme conditions, where jamming tends to occur, the solids or discharge passage will be opened to its maximum extent to permit discharge of the accumulations which have built up within the extrusion chamber.

To this end, on the shaft extension ll, I slidablymount a hollow cone 4'! with itssmall end open and adapted to slide over the hollow end 19 of the screw shaft. The cone is Provided with an inwardly directed collar 49 which is preferably, though not necessarily, keyed to the shaft extension, to preclude relative rotation of the cone with respect to the shaft, without impairing its ability to slide along such shaft extension. The base SI of the cone is formed with a plurality of integral bosses 53 distributedconcentrically of the shaft extension 4| for the purpose of anchoring therein a number of bolts 55 extending parallel to the shaft extension.

The shaft extension M is provided with a fixed piston 51, to each side of which there is aflixed a cupped leather washer 59 in which is placed a filler ring ti. These filler rings are held in place and at the same time serve to hold the cupped leather washers 59 in position against the piston, by means of a plurality of rivets or bolts 63, the heads of which are permitted to protrude from the filler rings.

The piston 57 is surrounded or enclosed by a movable cylinder ii iwhich is afiixed to the base ll of the cone, This cylinder includes a plate mounted on the bolts 55 and shaft extension 4|, in abutment against the cone bosses 53, and

.a flanged collar 81 slidably mounted about the shaft extension and having a flange 69 at one end and smaller flange II at the other end. The

I3 which is clamped therebetween by the application of clamping nuts 15 to the ends of the bolts. The internal end surfaces of the cylinder thus formed, are each provided with a cupped leather washer l6 and a filler ring 11 similar to those applied to the fixed piston 51. The holding rivets or bolts I8 for these washers I6 and rings 11, are positioned in alignment with the corresponding elements. 63 on the piston, so that when either end of the cylinder abuts against the piston, a residual chamber or space will remain. The cone and the cylinder, by reason of the construction just outlined, are accordingly ca pable of movement along the shaft extension, as a unit. The. extent of such movement is controlled by amovement limiting collar 19 which is threadedly attached to a cylindrical mounting 8| on the shaft extension ll, in spaced relationship to the shaft extension, and has an inturned flange 83 adapted to function as a limiting abutmentin the movement of the flanged collar 01 in either direction. The extent of travel or movement of the cone in the direction of opening of the discharge passage, may be increased by adjustment of this adjusting collar in the desired .opening direction, the adjusting collar being At the end portion of the shaft extension, provision is made for effecting a fluid connection from the outside, to each of these longitudinal bores. This portion of v the shaft extension is surrounded by a flanged stationary cap 9I which is bolted to the bearing supporting portion of the U-shaped bracket 42, with a partitioning wall 93 between the bracket and the cap, to create a chamber within the cap.

The cap chamber is divided into two compartments 95 and 97. One of these compartments 95 is connected with one of the longitudinal bores 85 by means of a connecting lateral bore 98, and provides for connection to an external duct or conduit 99 through an opening in the wall of the cap. Similarly, the second compartment 91 provides for connecting the other longitudinal bore 971 with an external conduit I91.

Each of the compartments in the cap is formed by a pair of oppositely disposed cupped leather washers I93 and I05, each witha flller ring IDI and I09, respectively, nesting therein. The oppositely disposed leather washer and flller ring assemblies are maintained in spaced relationship by a. spacer ring III which is perforated radially to maintain fluid connection between a longitudinal bore 85 or 81 in the shaft extension and its associated conduit 99 or IIII, respectively. These associated conduits 99 and IIII leading from the termed a "four way valve, may be of any well known construction or type ofwhich there are many on the market. The one which I have depicted as an element of the system, includes a valve chamber I23 of tubular shape. The two conduits 99 and I III connect to this chamher at spaced points on one side thereof, while the conduit I19 from the pump II5 enters the chamber from an opposite side thereof and at a point intermediate the connections of the other conduits, The return conduit Ml to the lubricant reservoir enters the valve chamber through the bottom thereof.

The valve H3 includes a plunger I25 within the tom of the plunger to intersect a transverse bore it I in the stem portion I33 of the plunger. The function of this bore is to provide for a liquid passage connection between the load conduit 99 and the return conduit IZI, when the plunger is cap compartments, connect with the load side of a flow reversin valve 3. The load side of such valve is considered as that part of the valve which is fluid connected to the load, which in this case is the adjusting cone assembly.

The source, of liquid utilized in the hydraulic control of the cone adjustment, preferably constitutes the lubricant reservoir in the gear housing I I, which, under the circumstances, performs the two entirely unrelated functions of (1) serving as the lubricant for the gear and pinion as.-

- sembly in the gear housing, and (2) constituting bricant reservoir, and is chain driven from a pulley I I! on the screw shaft extension 25 in the gear housing. A conduit 9 extends from the pressure side of the pump, and makes connection with the pump side of the flow reversing valve II3. A similar conduit I2I connecting with the flow reversing valve, also on the pump side thereof, extends back to the gear housing and terminates therein at a point preferably below the level of the lubricant therein, and serves to return the hydraulicfluid to the reservoir.

The fiow reversing valve H3, sometimes .75 in the dlechanelwer has a valve stem I" at the extreme end of one of its strokes, in its lowermost position, for example, as indicated in the drawings. In such position, the load conduit I0] associated with the closing operation of the cone, will be in liquid communication with the conduit "9 leading from the pump, and consequently will serve to carry fluid under pressure, to that side of the piston which will cause the cylinder to move the cone in the direction of closing of the discharge passage.

Any fluid in the cylinder on the other side of the piston will necessarily have to be discharged therefrom, to permit such movement of the cylinder, and such fluid will accordingly discharge through the other conduit 99, and through the return conduit I2I via the bore I29 in the plunger, from which conduit, the fluid will be discharged into the lubricant reservoir in the gear housing.

With the plunger in its uppermost position, the direction of flow in the load conduits 99 and I9] be reversed, and that portion of the cylinder ,to the right of the piston in Figure l will receive lubricant under pressure, to effect withdrawalof the cone from its previous position; Under such condition, the liquid on the other side of the piston will discharge through the load conduit IIII and valve chamber I23,

directly into the return conduit I2I, to the lu- Are-lief valve assembly I35 interconnects the 1 pump conduit "9 an'dthe return conduit I2I. This valve comprises a valve casing I31 partltioned by a-valve seat I39 to provide an intake chamber ill to which the pump conduit I I9 connects, and adischarge chamber I43 which connects with the return conduit I2I. A valve I protruding therefrom. A spring I, under compression, bears against the valve in the direction of seating the same. An adjusting screw I5I permits adjustments in the spring pressure to alter the operating pressure characteristics of the valve assembly.

K For all conditions or factors, short of producing jamming in the press, no change in the flow reversing valve is contemplated. Fluctuations or changes in the position of the cone 41, to vary the discharge path opening, are nevertheless provided for, to compensate for such conditions or factors, by the relief valve, the passage through which will vary in accordance with the prevailing pressure differential existing at any instant between the two sides of the hydraulic system. Such pressure diiferential will vary in response to any movement of the cone, brought about by the development of such factors or conditions which tend to disturb the existing pressure condition within the extrusion chamber. Thus, the pressure on the cone side of the piston will tend to increase in accordance with any tendency toward an increase in the pressure developing in the press. Such tendency toward an increase in pressure is in opposition to the pumping pressure, and consequently will cause opening of the relief valve to an extent sufiicientto take care of the overload on the pump and bring about a reduction in the prevailing tendency to-increase the pressure on the cone side of the piston. Such pressure relief is attributable directly to a slight reverse or back-flow of hydraulic fluid permitted by the opening of the relief valve. The relief valve is preferably made sufllciently sensitive to such tendencies toward pressure changes, that the pressure on the cone side of the-piston, under the conditions noted, will never be permitted to vary beyond the narrow range conducive to efiicient operation of the press.

The movement of the cone against such maintained hydraulic pressure, in the direction indicated, serves to relieve the increasing pressure condition developing within the press, while pre eluding. any substantial variation in the pressure within the extrusion chamber. Following elimination of the cause, the pressure within the press will tend to drop, -whereupon the cone will then move in the direction of its former position, under the hydraulic pressure: developed by the pump to maintain the pressure at the desired operating value, the relief valve in the meantime also being restored to its normal position.

As previously indicated, it is desired that the flowreversing valve 3 operate preferably only under such conditions as are apt to cause jamming of the press, and such reversal can be governedor controlled by the load placed upon the driving motor 31 undersuch conditions. Accordingly, the valve is provided with. a solenoid whereupon the plunger I25 will be moved to its other. extreme position, andbring about a reversal of flow of the liquid in the load conduits 99 and IllI. Such reversal of flow will shift the pressure from the cone side of'the piston 57, which normally tends to move the cone to closing position, to the other side of the piston, which shift of pressure will operate to slide the cone to its maximum permissible open position. With the cone in its maximum permissible open position, the greatest relief is offered to the press,

and such maximum open position will bemaintained so long as the relay I53 is energized, and this will be determined by the continued existence of such conditions within the press, tending to produce jamming. As soon as the, press becomes relieved of such condition, as by the discharge of any accumulated solid products from the extrusion chamber, the load on the driving motor will diminish to normal, causing the relay to drop out, and permit the plunger ofthe flow reversing valve to drop to its normal operating position.

The entire system is a fully automatic one, requiring no attention on the part of any operator. Any conditions developing in the press will accordingly'receive prompt response by the system, to compensate'for such conditions and relieve the same, to restore.the press to normal operation.

The system may, if desired, be made responsive to manual control on the part-of an operator, and the change is readily made, by eliminating the solenoid control on the flow reversing valve and incorporating in'the valve structure, a handle on the plunger stem I33, for operation by an operator, as and when desired.

It will be apparent from the above description of my invention that the same is capable of modification and alteration, without departing from the spirit of the invention, and I accordingly do not desire to be limited in my protection to the'specific details disclosed, except as may be necessitated by the prior art and the appended claims.

I claim:

1. An extrusion press comprising a compression chamber; means for compressing material in said chamber, said chamber having an opening therein through which to discharge material therefrom; and means for automatically maintaining a substantially constant pressure in said chamber in spite of pressure changing condi- I tions developing therein, said last means includ- I53 about the plunger stem I33, and this solenoid is connected across two of the lines suppwing the motor. If the motor is a three phase motor, as is indicated in the drawings, then the solenoid will be connected across any one of the phases. This solenoid circuit normally includes the open contacts I55 of a relay I51 in one of the reached, the relay will close its normally open contacts I55 and energize the solenoid I53,

ing an adjustable closure for said discharge opening, capable of opening in response to pressure increasing conditions developing in said chamber, a hydraulic system for controlling movement of said closure and including a cylinder and piston operatively associated with said closure, a source of liquid for said system, a feed line leading to said cylinder, a return line from said cylinder, a pump in said system for developing pressure liquid in said feed line, and a pressure sensitive shunt interconnecting said feed line and said return line to cause. a slight reversal in the flow of liquid sufiicient to maintain the pressure substantially constant.

2. In combination, an extrusion press having a pressure chamber with a discharge passage therefrom, a closure in said discharge passage adapted for operation to alter the capacity of said discharge passage to handle the discharge from said pressure chamber, a compression member in said pressure chamber, a motor in swim-y athrough said open end,

driving connection with compression member, a hydraulic system iorapplyliig pressure to said closure inthe direction of closing the same, i

a reversing valve in said sgstem adapted upon actuation, to reverse the pressure on said closure, and means responsive to an overload on through said open end, a shaft through said open end and ,apiston, a closure slidahly moimted on said shaftior operation into and out of said open end the e therethreugh; said closure'yha a new.

connected thereto and siidably encl :vi

'piston tocreate a piston c on eiside' of said piston, means for developing hydrac pressure'in one of said piston r movemeni; of said elosm-e toward open end of said compression chamber, a reversing valve for shifting said hydraulic Q'ressure so the other of said piston chambers and autamatic for actuating said valve noon the occurrence of an overload in said comon r 4. An extmsion press com a commsion chamber having an open end, a compression material fed therein and discs the e *insaid element in said r adapted to com gg said open end fps-altering the rge w i means or efieeising afull and quick one 1 response to an overload press-me.

8,8118. thrcugh said open endand a piston, a. closureslidaiiLv tfor operaiion mm and auto! said open to adjus the discharge therethrmlsh, said closure having a chamber connected thereto and slidably enclosing said nisbonto create a piston chamber on either side oi said piston, means for developing hydraulic in'one or said piston ciialii-v hers saidclosureandurgingthesame 'iowardthe opeziend or said-pressure chamber,

a relief valve includedin said hydraulic pres-- sure developing means; permitting movement of 7 said closure away ironfsaid open end in re said 1: while main 'saba:- hydraulic pressure against in 381d fed therein and 7 said open end, an adiustable cl at at said e'ndQmems normally urging said clasm' fig 13c the p of said disge, and

said clcsure in

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