US2204434A - Rolling mill - Google Patents

Description

June 11, 1940. 1 1,1, MUNSQN' 2,204,434

ROLLING 1111.1.

Filed July 16, 1937 2 Sheets-Sheet 1 INVENTOR JOSEPH J. MUNSON BY HIS ATTORNEYS June 1940. J. J. MUNSON 2,204,434

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Filed July 16, 1937 2 Sheets-Sheet 2 I L I 272 FIE? Z INVENTOR v JOSEPH J MUNSON v BY HIS ATTORNEYS Patented June 11, 1940 UNITED STATE v non-momma.

Joseph-J. Munson, Houma, La. Application July 16, 1937, Serial No. 154,058

8 Claims.

This invention relates to rolling mills of the type in which one or more floating pressure rolls are employed in opposition to one or more fixedaxis rolls in order to accommodate material of varying bulk as it passes between the rolls of the mill. More particularly the invention relates. to an hydraulic and pneumatic accumulator system for applying pressure to the floating rolls in mil of the type just mentioned.

10 In rolling mills of the aforementioned type as heretofore constructed the floating roll is provided for accommodating varying quantities of material passing through the mill. It is desirable to increase the pressure on the floating roll and on the material as the roll moves to accommodate larger masses of material. Many difllculties have been encountered in attempting to provide for a uniform increase of this pressure proportionate to the movement of the floating roll. In certain prior constructions the pressure has been constantly applied to the rolls by hydraulic means through the agency of plungers working in by draulic cylinders and acting to press the rolls against the material being crushed. These hydraulic cylinders were connected by conduits to an hydraulic accumulator, most commonly of the weight type. In this type a piston rises in proportion to the amount of fluid forced into the accumulator from the pressure cylinder at the floating roll as that roll rises. In order to increase the pressure in the hydraulic system and on the rolls in this type of mill, the accumulator piston was loaded automatically with a heavy weight after the piston had risen a predetermined distance, or it was loaded progressively with a series of weights as it reached predetermined points in its rise.

One defect of this type of accumulator is that the weight or weights must be started from rest and accelerated quickly to rather high velocity in order to take care of the varying displacements of the roll. Overcoming the inertia of the weights causes undue resistance when the roll moves quickly to accommodate heavy feeds and subjects the roll to undue shocknwhen it moves in the opposite direction in readjusting itself to normal or to lighter feeds. this type of accumulator is that it gives a nonuniform rate of applying the increase in load, or 50 if weights are progressively added then successive shocks occur; Another disadvantage of this weight type of accumulator is that due to the heavy moving parts there is often undue binding in the attempt of the machine to hold the heavy masses in line against their guides. A fourth Another disadvantage of (oi. loo-4'1) disadvantage occurs when lt is desired to change the pressure on the rolls for at that time it becomes necessary to remove or to add heavy weights, which make it impossible to'get quick changes in the loading.

A general object of myinvention'is to provide a pneumatic and hydraulic'accumulator system for applying pressure to the floating roll of a rolling mill to avoidthe aforementioned disadvantages and drawbacks of prior rolling millconstructions. 10

Another object of my invention is to provide a system for applying continuous pressure upon the floating rolls' of a rolling mill, which pressure is capable of automatic uninterrupted increase or decrease in response to an increase or decrease 15 in the work required of the mill.

1 Another object of my invention is to provide a system for applying pressure to the fl'oating roll of a rolling mill, which system will permit quick changes in the normal working pressure on the 20 floating pressure rolls and which will at the same time permit any desired variation in the normal W(1)1lking pressure within the pressure limits of the Another object of my invention is to provide apparatus for a system for applying pressure to the floating'roll of a rolling mill, which will avoid the -use of heavy or cumbersomeparts having a tendency to bind in their movement. This object is to beaccomplished while providing pressures 3 upon the movable roll equally as great as those in prior constructions.

Other objects and-advantages of my construction will become apparent as itis described in connection with the accompanying drawings. 85

This application is a continuation-in-part of my prior application Serial No. 1457, filed on J anuary 12, 1935, patented Dec. 7,1937, No. 2,101,266. and entitled Rolling mills. The invention in the present applicationas well as in my prior ap- 40 plication is illustrated as applied to a rolling mill for crushing of sugar cane, but is capable of other 7 uses.

of apparatus embodying the principles of my new system for controlling pressure rolls.

Referring to Figure l of the drawings, a. portion of one of the rolling mill sections of a sugar cane crushing and rolling mill is shown for the purpose of illustrating the invention. In practice a main bedplate serves to mount axially spaced side frames or standards 2 of the mill. Journalled within the side frame are front and rear cane crushing rolls (not shown) with their axes of rotation arranged substantially in a common horizontal plane. The axes of these rolls are fixed and the rolls are journalled in suitable bearings which are maintained in suitable relative position in the side frames or standards. To simplify the showing of the invention these fixed rolls have been omitted from' the drawings. Mounted above and substantially centrally with respect to the lower fixed rolls is a top floating pressure roll I which may move vertically and partake of a tilting movement during the application of pressure to its bearing. As shown in Figure l the upper bearing member of each journal of the floating roll is constructed in the form of a bearing block 8 which carries a pressure block 9. This pressure block is provided with an upper bearing surface l0 shaped to permit the pressure block to adjust itself angularly over the concave lower perimetric surface of a chambered cap I! which is joined to the bottom end of a hydraulic plunger 52. During the rising and falling movement of the floating pressure roll the bearing members or blocks are in slidable engagement with guide surfaces formed in the side frames and operate to counter-balance the binding effect in the manner described in my copending application Serial No. 1,457. The plunger I2 is mounted for reciprocation in a cylinder I3, which is closed at the top by a cover block l4 arranged below and held in place by the mill housing cap I5. The cap is bolted to the side frame or pedestal.

The hydraulic pressure chamber in cylinder 13 may be sealed above and below by leather packing cups l6 and IT. For holding the packing cups in place circular plates Hi and I! may be seated within the cups and pressed against them by a compression spring l8. The chamber within the cylinder l3 may be connected to a source of pressure liquid, as hereinafter described by means of pipe 22.

In order that a portion of the heavy pressures which are usually transmitted through the contacting metal surfaces of the plunger l2 and pressure block 9 may be transmitted by direct application of hydraulic pressure to the pressure block 9, the plunger l2 may be provided with an opening or passage l9 extending through to an auxiliary pressure fluid chamber 20 formed between the lower end of the plunger l2 and the top wall of the pressure block 9. By this means the contacting metal surfaces are relieved of any desired portion of the friction-creating stresses transmitted through the contacting portions of the hydraulic plunger [2 and pressure block 9.

In order that the force on plunger l2 may be intensified or in order that the displacement of liquid from cylinder 13 may be accommodated, the pipe 22 connects with an hydraulic cylinder 23 through a T-fitting 24, one branch of which fitting is connected to a supply pipe 25 from an hydraulic pump (not shown). A hand valve 26 may be included in the supply pipe 25 for controlling the admission of oil to the hydraulic system from the pump. Working vertically within the cylinder 23 is an hydraulic plunger 21 whose upper end extends outside the cylinder 23 and has mounted upon it a piston 28 which works within a cylinder 29. This cylinder 29 is of larger diameter than the cylinder 23 and is supported upon columns 3| rising from the bedplate 32 of the hydraulic cylinder 23. During the operation of the apparatus this cylinder 29 is always full of oil or other pressure liquid. The oil is initially supplied to cylinder 29 through a supply pipe 48 connected to a neck or fitting 50 located on the head of the cylinder 29 for oil passage in and out of the cylinder. The pipe 48 may be connected with a suitable supply of oil and the delivcry of the oil may be controlled by inserting control valve-4! in the pipe line.

Mounted preferably above the cylinder 29 is an accumulator which is connected to cylinder 29 by the pipe 34 leading from the bottom of the accumulator to the neck in the head 33 of the cylinder 29. This accumulator 35 is only partially filled with oil from the cylinder 29. The upper part of the accumulator contains air under compression, received through a pipe 3'! connected to a compressed air tank 36. The accumulator is thus a combined pneumatic and hydraulic accumulator. In order that the oil within the accumulator 35 may not get into the compressed air system, the connection of the pipe 31 will preferably be made to the top of the accumulator.

In order that the pressure within the pipe line 31 shall not rise above a predetermined amount a safety valve 39 is provided therein. In order that a predetermined pressure shall be maintained in the accumulator 35 a check valve 40 is also provided in the pipe line 31. A pressure reduction valve 38 is also placed in the pipe line 31 between the compressed air source 36 and the accumulator 35. This reduction valve has a bypass fil around the check valve and safety valve. The by-pass is connected to a diaphragm 42 of the pressure reduction valve, this diaphragm working against the resistance offered by the compression spring 38 for operating the reduction valve. The reduction valve may be easily adjusted. Thus the normal loading of the accumulator may be easily and quickly varied in contrast to the slow cumbersome process which had to be gone through in prior systems.

In order to limit the pressure rise within the accumulator 35 to a predetermined amount a safety valve 44 is connected to one branch of a T-fitting 43 attached to the upper end of the accumulator. A hand operated valve is connected to the other branch of this fitting for the purpose of unloading the accumulator. This hand valve is a valuable part of the invention for by means of it the system may be quickly unloaded and the rolls relieved of pressure as occasion arises, for example, when the normal loading is to be varied. A pressure gauge 46 may be connected to the accumulator above the surface of the oil.

The operation of the system just described is as follows:

Before the mill is put into operation, the floating pressure roll I will be in its lowermost position, as illustrated in Fig. 1, and the plunger 21 will be at the bottom of its cylinder 23. The valve 26 in the oil supply line 25 for the hydraulic pressure end of the system will now be opened in order to admit oil to the lower end of cylinder 23 to fill pipe 22 and roll pressure cylinder I3, after which thevalve is allowedto redistance of approximately 6 in. Valve 28 will "now be closed. The valve 41 in the oil supply line for the pneumatic end of the system will now be opened and the cylinder 28 will fill with oil and the accumulator will be filled up to some level such as indicated by the dotted line K. Valve 41 will then be closed. Manual valve 48 in pipe line- 31 will now be opened to admit compressed air from the compressed air source 38 through the reducing valve 88 and check valve '48 to the top of accumulator 85. The manual valve 48 is left open during the operation of the system. It may now be seen that the pressure from the pneumatic accumulator system (consisting oi the apparatus between the compressed air source 88.

and the piston 28) will be communicated to the hydraulic pressure system (consisting of the apparatus between the plunger 21 and the roll bearing 8) in the following manner: The pressure in the accumulator is transmitted through the oil 30 within the cylinder 28 to the piston 28 and plunger 21 and through the oil in the pipe 22 to the roll-pressure cylinder l3 and plunger l2 working therein, and through the plunger l2 and associated parts to the roll 1, putting the roll under pressure. The piston 28 and plunger 21, it may be seen, forms the tie between the hydraulic and the accumulator systems. j

As the mill is'put in operation rise of the pressure roll 1 will be accompanied by a rise of the plunger i 2 and displacement of the oil within cylinder I 3 will cause a rise of the'plunger 21 and proportionate displacement of the oil within the cylinder 29. This will raise the level of the oil in the accumulator 35 to some such point as M and reduce the volume of the fixed quantity of air above the oil, thus increasing the pressure in the accumulator according to the laws of behaviour of fixed quantities of perfect gases. The rate of increase (or decrease) of pressure will be uniform inthe sense that it is continuous and uninterrupted, although the variation in pressure is not in direct proportion tothe rise in oil level but is expressed by the exponential equation for the behaviour of gases, as will be apparent to those familiar. with laws of the expansion and contraction of gases. Obviously the degree of pressure increase may be controlled by varying the height of the oil in the accumulator, or in other words, by varying the initial volume of air in the accumulator. Check valve 48 during increase of pressure within the accumulator will prevent loss of pressure by air flowing back to the compressed air source through the pipe 31.

Obviously the total load imposed upon the roll 1 through its bearing may be changed at will by changing initial air pressure within the accumulator.

In Figure 2 of the drawings another form of the invention is diagrammatically illustrated in which the pipe I22 affords a direct communication between the roll pressure cylinder l3 and the In a system of this form the accumulator i35. relation of the volume of oil displaced within the pressure cylinder I3 (at the roll) to the volumeof the accumulator must be proportioned sothat the proper amount of pressure increase, as the roll moves, is provided by the decreasing air volume in the accumulator.

In Figure 3 another form of the invention is illustrated. In this formthe showing of the mill has been omitted but it will be observed that the pipe 22 is provided for connecting the mill to an hydraulic cylinder 223 in which works vertically a plunger 221'whose' top extends outside the cylinder 223 and has mounted upon it a piston 228. To indicate the position of the plunger 221 and its piston 228 and to prevent them from rotating about their axes, a pair of parallel guide rods 268 are provided in position to extend from the lower face of the piston through the bottom of a hollow cylindrical casing 235". Said bottom may be formed integrally with the cylinder 223 at its upper end. The casing 285 may have a top flange 264 which is secured to a flange 212. on the bottom of the upper section 235. of an accumulator cylinder. Suitable packing may be applied to the top surface and secured thereon or ordinary piston rings 210 may be used in connection with piston 228to prevent leakage. The piston works in the lower section 235 oi! the accumulator as illustrated. As in the previously described forms of the invention, oil or other liquid maybe fed to the hydraulic system by a pipe 25 through a valve 26 therein from the oil supply and to the pipe 22. As in the previously described form the accumulator 235 is partially filled with oil.

To accomplish this purpose a pipe 216 is connected to the upper accumulator section 235 and to the bottom oi! an oil supply tank 218. A valve 280 may be placed in the pipe 216 to control the flow of oil into the accumulator. An oil inlet connection is provided on the top of the oil- As in'the previously described forms of the invention air under compression is supplied to the accumulator by a pipe 231 connected to the top of the accumulator section 235 and leading from a source of compressed air 236. In this pipe 231 a manual control valve 248, a pressure reduction valve 238 and a check valve 240 are inserted, as previously. The accumulator also is provided with safety valve 244 and a manual unloading valve 245.

In order that the force of the compressed air may be used to force the oil from the oil tank '218 into the various parts of the apparatus a pipe 282 from the. compressed air: supply 236 to the top of the oil tank 218 is provided. A manual control valve 284 is provided in this pipe adjacent the tank.

The operation of the form shown in Figure 3 is similar in principle to the form illustrated in Figure 1. In Figure 3 the oil is admitted to the hydraulic cylinder 223 through pipe 25 and control valve 26 in the same manner as the admission of oil to cylinder 23 in Figure 1. This fills up the hydraulic end of the system and elevates the piston 228 to a suitable height, such as shown in Figure 3. The valve 26 is then closed.

To admit oil to the accumulator the valve 249 in the compressed air line is closed andthe valve 284 is opened, admitting air to the oil tank 218 and forcing oil through the pipe 216 into the accumulator through valve 280 which will be open. When the oil has reached a suitable height, such as shown at K, the valves 280 and 286,. are closed. The operation of the accumulator from this point is similar to the form shown in Figure 1, it being obvious that as the piston 228 rises, due to the movement of the pressure rolls, so also will the level of the oil in the accumulator rise to a point such as M, and in so doing there is created a gradually increasing back pressure which is transmitted through the system to the rolls.

Although the system as described is for one mill only it may be adapted for additional mills by providing additional accumulators, piping and valves since the compressed air source 236 and oil receptacle 218 may serve any number of mills. It will be understood that. the application of pressure to the rolls may be at each end of each roll, thus permitting tilting of the roll in the usual manner but under the control of my improved accumulator pressure system.

From the foregoing it will be apparent that my system eliminates the use of heavy weights or masses which would have to be started from rest and accelerated to high velocities as the material passing between the rolls varied in mass and that my system avoids the undue resistance to raising of the roll and undue shocks as the roll adjusts and readjusts itself to various feeds. It will also be apparent that by the use of my pneumatic system the desire for automatically increasing the pressure on the rolls in a continuous uninterrupted manner is completely satisfied and the defect in prior devices of non-uniform loading overcome. It will also be observed that by the use of light, though ample, guides for the light moving parts, I have overcome the defect in the prior devices of lateral binding. Finally it will be observed that by reason of the provision of the reducing-valve and vent valve the mill may be instantly unloaded or'the load may be quickly increased to provide any desired loading within the strength limits of the mill, thus avoiding the delay incident to change of loading of prior apparatus for a similar purpose.

Obviously the form of the accumulator and various other parts employed in my invention may be varied by those skilled in the art without departing from the scope of the invention. Therefore I do not limit myself to the specific form of the various parts as illustrated and described.

I claim:

1. In a mill for rolling sugar cane and like materials requiring extremely high pressures, a floating roll, a plunger for applying pressure to said roll, and hydraulic means to apply pressure to said plunger comprising a cylinder, a plunger in said cylinder for placing said hydraulic means under pressure, said second plunger being of less cross-sectional area than said first plunger, pneumatic, means for normally supplying constant pressure and comprising a second cylinder, and

a piston in said second cylinder subjected to the pressure of said pneumatic means, said piston being of greater diameter than said second plunger and connected for unitary movement with said second plunger, and said pneumatic means increasing the pressure on the roll in a continuous and uninterrupted manner in response to movement of the roll in accommodating increased masses of material passing through the mill.

2. In a roll mill for rolling sugar cane and like materials requiring extremelyhigh pressures, the combination with a floating roll, of a bearing for said floating roll, an hydraulic press for applying pressure to said bearing, and hydraulic press and accumulator means for applying continuous pressure to said bearing press and for causing increased pressure on said bearing as the roll moves to accommodate increased feed, said press and accumulator means comprising an hydraulic cylinder connected to said bearing press, a plunger operating in said cylinder, a compressed air and liquid accumulator, and a piston working within said accumulator having cross-sectional area greater than the cross-sectional area of said plunger and connected for unitary movement with said plunger.

3. In a roll mill for rolling sugar cane and like materlals'requiring extremely high pressures, the combination with a floating roll, a bearing for said floating roll, an hydraulic press for applying pressure to said bearing, and hydraulic press and accumulator means constructed and arranged for applying continuous pressure to said bearing and for causing increased pressure on said hearing as the roll moves to accommodate increased feed, said press and .accumulator means comprising an hydraulic cylinder connected to said bearing, a plunger operating in'said cylinder, a pneumatic and liquid accumulator, a piston working within said accumulator and having a larger cross-.sectional area than the cross-sectional area of said plunger, and means to vary the quantity of liquid in said accumulator for the purpose of varying the maximum possible volume of gas therein and correspondingly varying the degree of pressure variation per unit of piston movement.

- 4. Ina mill for rolling sugar cane and like materials requiring extremely high pressures, a floating roll, a plunger for applying pressure to said roll hydraulic means to apply pressure to said pllnger, pneumatic means for normally supplying constant pressure, and means for transmitting the pressure of said pneumatic means to said hydraulic means comprising a cylinder, 2. piston in said cylinder subjected to the pressure of said pneumatic means, a second cylinder of less diameter than said first cylinder, and a plunger operating in said second cylinder to apply pressure to said hydraulic means, said second plunger being of less cross-sectional area than said first plunger and said second plunger and piston being connected for operation as a unit, and said pneumatic means being responsive to movement of said roll to increase and decrease in a continuous and uninterrupted manner the pressure on said roll as heavy and light feeds pass through the mill.

5. In a mill for rolling sugar cane and like materials requiring extremely high pressures and having a floating bearing, the combination with an hydraulic press having a plunger for applying pressure to said floating bearing, of a pressure accumulator, a cylinder connected to said pressure accumulator and hydraulic press, a differential piston in said cylinder forming therein upper and lower variable volume compartments of different cross-sectional areas, the compartment of greater cross-sectional area being connected to said accumulator, the compartment of lesser cross-sectional area being connected to said press, and means to maintain the pressure in said accumulator up to a. predetermined minimum pressure.

6. In a roll mill for rolling sugar cane and like materials requiring extremely high pressures, the combination with a floating roll, of a bearing for said roll, and hydraulic press and accumulator means for applying continuous pressure to said bearing and for causing increased pressure on said bearing as the roll moves to accommodate increased'feed, said press and accumulator means comprising a hydraulic cylinder connected to apply pressure to said bearing, a plunger operating in said cylinder, a pneumatic and liquid accumulator, and a piston working within said accumulator, said plunger and said piston having diflerent cross-section area sizes and being constructed and arranged to transmit the movement of the roll to said pneumatic means with multiplied effect.

'7. In a mill for rolling sugar cane and like materials requiring extremely high pressures, a floating roll, a bearing for said roll, and hydraulic means to apply pressure to said bearing, comprising a cylinder, a plunger in said cylinder under pressure, pneumatic means for supplying continuous pressure and including a second cylinder, and a piston in said second cylinder subjected to the pressure of said pneumatic means, said piston being of greater diameter than said plunger and connected for unitary movement with said plunger, and said pneumatic means including a body of liquid forming a seal for said piston and being responsive to movement of said roll to increase and decrease in a continuous and uninterrupted manner the pressure on the roll as increased masses of material pass through the mill.

, 8. In a mill for rolling sugar cane andlike materials requiring extremely high pressures and having a floating bearing, the combination of a hydraulic press having a plunger for applying pressure to said floating bearing, 01' .a pressure accumulator, having a cylinder containing a liquid body and a volume of gas, a piston for moving said liquid bodyand having a larger area than said plunger whereby to transmit the movement of said bearing to said accumulator with multiplied eflect, and means to maintain the pressure of said gas up to a predetermined minimum, and means associated with said pressuremaintaining means to vary the volume of liquid in said accumulator whereby the rate of pressure increase and decrease in response to movemen of said hearing may be varied.

JOSEPH J. MUNSON.

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