US2281294A - Press for paper making machines - Google Patents

Description

April 28, 1942. B. A. MALKIN PRESS FOR PAPER MAKING MACHINES Filed June 20, 1940 INVEMTOB/ ERNARDAMALKI ATTGRNE S designed in accordance Patented Apr. 1942' PBESS FOB PAPER MAKING MACHINES Bernard Abbott Malkin; Lachlne, Quebec, Can

ada, assign Limited,

or to Dominion Engineering Works Lachine; Quebec. Canada Application June 20, 1940, Serial No. 341,514

4 Claims.

This invention relates to three roll presses and is a continuation, in'part, of the invention disclosed in my co-pending application Serial No.

, 159,939, filedAug. 19, 1937.

In its preferred embodiment my invention comprises a top press roll and two bottom press rolls arranged with their centers at the corners of a triangle. The first bottom roll is preferably a suction roll while the top roll and the second bottom roll are preferably plain rolls. A pressure applying means is arranged to act against the top roll to give an evenly distributed line pressure between both hips and is controllable to vary the intensity of such pressure. A second pressure applying means is also arranged to act against the top roll to give an additional nip pressure between bottom roll so that this nip pressure is greater than the nip pressure between the top roll and the first bottom roll. The line of action of the first mentioned pressure applying means is midway between the centers of the two bottom rolls and perpendicular to a line joining said centers. The line of action of the second pressure applying means is substantially along the projection of a line through the centers of the top roll and the second bottom roll. The two pressure applying means are independently controllable so that the intensity of the evenly distributed line pressure obtained through the agency of the first mena tioned pressure applying means may be varied without varying the ratio which the nip pressure on the second roll bears to the nip pressure on the first roll or so that the ratio of the two nip pressures-can be varied without varying the intensity of the evenly distributed line pressure obtained through the agency of the first mentioned pressure applying means. It is also possible that the pressure applying means described herein may be controlled to vary both the ratio of the nip pressures and the intensity of the evenly distributed line pressure by varying the action of both or the pressure applyingmeans. I

Proceeding now to a more detailed description reference will behad to the accompanyi g draw...

ing. inwhich I Fig. 1 is an end elevation of a three roll press with this invention.

pressed from the paper web during its passage through the first nip of the press. The press felts are generally indicated at It and H and may be guided and tensioned by a suitable arrangement of guide and stretcher rolls.

The top press roll i2 is positioned between and rests upon the bottom rolls and 6 so that the v.centers of the three rolls are located at the three the top roll and the second As shown in the drawing, the first and second 1 bottom rolls 5 and 6 are respectively journalled in suitable bearings 1 mounted on the frame 8.,

The first bottom roll 5 is preferably a suction roll which may be of any suitable design and serves. in addition to its pressing function, as a convenient means for quickly removing the water corners of a triangle. Each end of the top roll shaft i3 is journalled in a split bearing ll provided at the lower end of a link [5. The upper end of link I5 is fastened, by a pivot it, to the end lid of a pressure applying lever l6. As here shown each lever i8 is intermediately pivoted, as at i'l, to a bracket I8 rising from the frame 8 adjacent the suction roll 5. The end I9 of each lever is connected by a link 20 to one end of a lever 2| which is intermediately pivoted to the bracket I! as indicated at 22. The remainin end of lever 2| is pivoted to the upper extremity of a piston rod 23 having its lower extremity fastened to a piston 24 working in a cylinder 25, the

lower portion of said cylinder being pivoted to the frame 8 as indicated at 26 to provide a pivotal axis about which the cylinder is free to oscillate. Pressure fluid, such as air or liquid, is alternately supplied to and exhausted from the upper and lower ends of cylinder 25 through ports 21 and 28 provided for this purpose. The cylinder 2 5 is preferably connected in circuit with a source of fluid under pressure so that, through the agency of suitable control valves (not shown) pressure fluid may be supplied to the upper end of the cylinder 25 through port 21 and simultaneously exhausted from the lower end of the cylinderthroughport 28 and viceversa. When pressure fluid is supplied to the upper end of cylinder 25 the resulting downward pressure on piston24 is transmitted, through the piston rod 23, lever 2|, link 20, lever 16 and link I 5, to the top roll i2. When the press is in operation the link i5 occupies the inclined position shown in the drawing so that one side of this link is spaced from a shoulder formed by a lateral projection l6c of the pressure applying lever It. In this connection it will be noted that the centers of the rolls 6 and I2 and the pivot point it are aligned so that the line of action of the downward pressure applied to the top roll by the pressure applying levers I6 is along the projection of a line throughthe centers of the rolls 1 and i2.

' Consequently, the downward pressure applied to the top roll through the linkslS-and pressure applying levers It gives a greater nip pressure as compared with the nip pressure between the top roll and the first bottom roll 5, The intensity of the downward pressure thus applied to the top roll l2 can, of course. be varied by appropriate operation of control valvesv included in the hydraulic connections between the cylinder 25 and the source or fluid under pressure.

Each of the split bearings H in which the top roll i2 is journalled is provided with a downwardly directed lug 38 which is fastened by a coupling link 3| to the upper end of a rod 32. The lower end of rod 32 is attached to a pin extending at right angles to the main portion of the rod to provide an arm 33 which is seated in a notch 34 provided in the lower edge of a lever 35 having one endpivoted to a bracket 36 carried by the frame 8. The remaining end of lever 35 is pivoted to the upper end of a piston rod 31 connected to a piston 38 working in a cylinder 39, the lower end of said cylinder being pivoted to the frame 8 as indicated at 40. Cylinder 39 is provided with ports 4! and 42 which correspond to and serve the same purpose as the ports 21 and 28 of the previously mentioned cylinder 25. Cylinder 39 is also connected in a hydraulic circuit including a source of fluid under pressure so that fiuid may be admitted to the upper end of cylinder 39 through port 4| and simultaneously exhausted from the lower end of said cylinder through port 42 and vice versa. When pressure fluid is admitted to the upper end of cylinder 39 through port 4| the downward pressure on piston 38 is transmitted to the top press roll i2 through the agency of piston rod 31, lever 35, rod 32, link 3|, lug 30 and bearing l4. It

will be noted that the rod 32 and the terminal pivots of the link 3| are aligned with each other and with the central vertical axis of the roll l2. Consequently, it will be seen that the line of action of the downward pressure transmitted to the roll l2 through the agency of the rod 32 is midway between the centers of the two bottom rolls 5 and 6 and is perpendicular to a line Joining said centers. It will therefore be seen that when downward pressure is applied to piston 38 the tension developed in the nip pressure rods 32 gives an evenly distributed line pressure on both nips which may be varied in intensity without varying the difference in nip pressure between the first and second nips.

Each of the tension rods 32 is adjustable in length, being made in two sections connected by a turn buckle 3211.

When it is desired to lift the top roll 12 clear of the bottom rolls 5 and 6, this may be accomplished by disrupting the connection between the top roll and the tension rods 32 and supplying fluid to the lower ends of cylinders 25 to force the pistons 24 upwardly. This upward movement of pistons24 acts through the piston rods 23, levers 2|, links 20, pressure applying levers i6 and pressure distributing links l5 to raise the top roll l2 and the latter may be held in its raised position by engaging a hook 43 beneath a portion of pivot 22. In this connection it will be noted that hook 43 is pivoted to a bracket 44 carried by the pressure applying lever l6. It will also be noted that during the upward movement of the levers IS the lateral projections or shoulders l6c act against the adjacent sides of the pressure distributing links I 5 to raise the top roll i2.

If desired, the top roll i2 may be a hollow heated roll to which steam or other heating medium is supplied in any desired or well known manner.

The invention also contemplates the employment of a suction roll as the top roll or second bottom roll of the press in which event the first bottom roll would be a plain roll. These and other desirable modifications are contemplated as falling within the scope and spirit of the invention as defined'by the appended claims.

Having thus described my invention, what I claim is: l. A press for paper making machines comprising a top Dress roll and two bottom press rolls arranged in triangular formation, pressure applying means acting against the top roll to give an evenly distributed line pressure between both him and a second pressure applying means also arranged to act against the top roll to give an additional nip pressure between the top roll and the second bottom roll so that this nip pressure is greater than the nip pressure between the top roll and the first bottom roll, said flrst mentioned pressure applying means comprising a 7 cylinder, a piston working in said cylinder and a pressure transmitting connection through which downward pressure on said piston is transmitted to the top press roll so that the line of action of the pressure thus transmitted is along the projection of a line through the center oi the top roll midway between the centers of the two bottom rolls and perpendicular to "a line joining the two last mentioned centers.

2. A three roll press comprising a top roll and two bottom rolls arranged in triangular formation and means for exerting downward pressure on the top roll to give a nip pressure between the top roll and the second bottom roll which is greater than the nip pressure between the top roll and the first bottom roll, said means comprising a pair of pivotally mounted pressure applying levers, inclined links connected between the levers and the top roll, said links being pivoted to said levers so that the centers of the pivotal connections between these parts lie on the projection of a line through the centers of the top roll and the second bottom roll, a pair of cylinders, pistons working in said cylinders and pressure transmitting connections between said pistons and said levers.

3. A press for paper making machines comprising a top press roll and two bottom press rolls arranged in triangular formation, pressure applying means acting against the top roll to give an evenly distributed line pressure between both nips and a second pressure applying means also arranged to act against the top roll to give an additional nip pressure between the top roll and the second bottom roll so that this nip pressure is greater than the nip pressure between the top roll and the first bottom roll, said second pressure applying means comprising a pair of pressure applying levers intermediately pivoted to swing about a common horizontal axis located at one side of the top roll, said levers being arranged so that one end of each layer extends inwardly over the first botttom roll while the other end is disposed at the side of the first bottom roll remote from the top roll, means for exerting up-' ward pressure on the last mentioned ends of the levers and pressure transmitting connections through which downward pressure is transmitted to the top roll along the projection of a line through the centers of the top roll and the second bottom roll, said connections comprising pressure transmitting links having their upper ends pivoted to said levers and having bearings at their lower ends in which the shaft of the top roll is the top press roll along the projection of a line through the center of the top roll midway between the centers of the two bottom rolls and perpendicular to a line joining the two last mentioned centers, a second movable pressure applying member and pressure transmitting con nections through which downward pressure is transmitted from said last mentioned member to the top roll along the projection of a line through the centers of the top roll and one of said bottom rolls.

BERNARD A. MALKIN.

pressure is transmitted from said member to

Images