US2690099A - Vacuum slice for paper machines - Google Patents

Description

F. J. REILLY VACUUM SLICE FOR PAPER MACHINES Sept. 28, 1954 Filed March 15, 1950 Patented Sept. 28, 1954 UNITED STATES PATENT OFFICE 2,690,099 VACUUM 'SLICE FOR PAPER MACHINES Franklin J. Reilly, Chicago, Ill. Application March 15, 1950, Serial No. 149,697

2 Claims.

a substantial pool of water to be collected between the slice and the nip of the adjacent press rolls.

According to the present invention, the conventional pool-forming placed by a vacuum slice which operates to remove the expressed water at a rate which is to prevent the formatmn of any substantial pool slice above referred to is reconsidered practicable, thereby increase the productive capacity of the machine. 1

It is also an object of the present invention to provide water removing equipment of the charing equipment without significant alterations to the paper making machine or the press roll section thereof.

Other objects and advantages of the invention will be understood by reference to the following specifications and accompanying drawing in which there is illustrated a vacuum slice embodying a selected form of the invention and the manner in which the same is associated with a pair of press rolls of a paper making machine.

In the drawing,

Fig. 1 is a more or less schematic end'view illustrating the manner in which the improved vacuum slice is associated with a pair of press rolls and the paper carrying felts which are acted upon by the press rolls;

Fig, 2 is a plan section approximately 'on the line 22 'of Figs. land 3;

Fig. 3 is a cross section on the line 3-'3' of Fig. 2.

In the drawing, one pair of press rolls is represented by upper and lower rolls 1 and 2 respectively, these rolls acting on a pair of paper carrying felts which are directed between the rolls. An upper felt is indicated at 3 and a lower felt at 4, a paper web 5 being confined between these felts pressure which they exert on the paper carrying felts. Some of the water squeezed out of the paper flows downwardly over the lower roll 2 and out of the upper surface of the upper felt 3 and tends to collect on the surface of the felt and against the surface of the roll I. This follows from the fact that the felts are moving at a fairly fast speed toward the rolls l and 2 so that any water collected on the surface of the upper felt is carried toward the surface of the roll I.

To remove the water which collects in this'manner on the top of the felt 3, I provide a slice 6 which extends transversely over the entire width and preferably, somewhat beyond the edges of the felts. This slice is pivotally supported adjacent its front edge by a cross shaft I so that its rear or intake edge '8 may be vertically adjusted relative to the surface of the upper felt 3. The cross shaft 1 is suitably supported on the framework of the paper machine by brackets or any other acceptable manner, and the intake edge 8 of the slice is supported to bear on the felt 3 under controlled pressure. To that end there is provided at each end of the slice, an adjusting device which comprises a screw-threaded rod 3 suitably anchored to the slice as indicated at it and extending downwardly and slidably through a suitably apertured ear or bracket element ii which is rigid with the frame structure of the press section of the paper machine, A pair of nuts W. on the threaded rod 9 above the supporting ear or lug ii serves to sustain the intake edge 8 of the slice in the desired relationship to the surface of the upper felt 3. Spring means indicated at it about the rod ii and under compression between the lower side of the ear or lug i l and a wing nut Ed on the rod serves to yieldingly hold the intake edge of the slice against upward displacement.

The supporting bolt 9 should be adjusted to cause the intake edge or toe of the slice to ride on the surface of the overlying felt with an ironing or smoothing action thereon, whereby smooth paper web formation is attained and objectionable bunching and wrinkling of the felts avoided. The slice comprises a rigid frame structure having a pair of end members iii and it which are rigidly interconnected by means of a longitudinally extending bar ii. This frame structure may be formed as an integral unit by casting or it may be fabricated from separate pieces as pre-' ferred.

A bottom plate It is suitably secured to the frame members it, it and ii on the rearward or pressure roll side of the member H and a cover plate is is secured to said members it, it and H in overlying relation to the bottom plate iii, thereby to cooperate with the latter and with said members it, it and ii to form a chamber 26. This chamber it is closed except at the rear edge of the slice where an intake opening or slot is provided as indicated at 2 i. This intake opening or slot is provided between the rear edge 22 of the bottom plate 88 and a bead 23 which is formed at the rear edge of the cover plate 19. This bead may be bent up or down to adjust the width of said slot or intake opening 2!. The width of this opening does not appear to be critical and adjustl ment thereof by bending said bead as aforesaid is an adequate provision for that purpose. However, other forms of adjustment may be provided if desired. The said bead or lip 23 provides a baiiie which serves to prevent or at least reduce the flow of water over the nozzle and thence endwise along the nozzle and off the same beyond the edges of the felts.

The bottom plate it has its rear edge portion bevelled or charnfered as indicated at M to pro vide a smooth non-cutting felt engaging surface.

For adapting the slice to various widths of felts, adjustable end walls are provided adjacent the opposite ends of the slice between the bottom plate It and cover it. These end walls 25 may each be made of a single plate element, but as here shown, they each comprise two parts indicated at 26 and 21, each part having a screw post 23 rotatably secured thereto. The screws 28 are threaded through suitably tapped openings which extend through the end members it or Iii. By rotating the screws 2%, the end wall sections or parts will be moved inwardly or outwardly according to the direction of turning of the screws and the direction of the threading. By this means, the effective length of the nozzle opening 2! and the chamber 25 may be substantially conformed to the width of the felts as shown. l lieeting edges of the members 26 and all are preferably formed by bevelled faces indicated at Inside of the chamber it), there is provided a vacuum pipe 3! which extends along the entire length of the slice and projects through said end members if) and i6. At one end, the vacuum pipe 3! is closed by a screw plug 32. The other end of the pipe is screw-threaded or provided with any other suitable fitting for facilitating connection of the pipe to an exhaust pump or other source of suction. Such connection is preferably made by means of flexible tubing such as high pressure hose which will resist collapsing under the effect of suction. The pipe may be removably or fixedly secured to the frame members it and it, and in this instance it may be assumed to be fixedly welded or brazed to said frame members.

The suction pipe 3i is provided with a plurality of laterally extending branches in this instance three such branches, disposed at suitably spaced intervals to approximately uniformly distribute the suction eifect of the nozzle ends 34, of said branches over the effective length of the slice. In the construction illustrated, the slice is shown as tapering in its width from the main body portion thereof containing the suction pipe iii to a reduced width or thickness at its intake edge. This facilitates positioning of the intake edge of the slice quite close to the nip of the press rolls. The branch suction conduits or pipes have their intake ends somewhat flattened as indicated at 36 to permit such end portions to closely approach the intake edge of the slice.

The suction pipe M with its branches pro-- vides an effective means for removing and carrying away any water which collects on the surface of the top felt. This suction pipe and branches, without the enclosing structure provided by the bottom and top plates it and I8 and the frame member ll, may be employed for the purpose of removing water but much greater efficiency is obtained by enclosing said suction pipe structure in the chamber 29.

It will be observed that the branch suction pipes 33 and their inlet ends are of relatively small cross section and that the combined areas of the passageways in said suction pipes 33 is but a small fraction of the area of the intake opening or slot 2i of the nozzle of the slice. The branch suction pipes 33 are normally operated under a degree of vacuum or suction which 131K," duces a high velocity flow of water into the said suction pipes. The high velocity of water iiow results in a water flow rate through said suction pipes which may be maintained substantially equal to the water flow rate through said nozzle opening 2! into the nozzle so that a balanced or substantially constant condition may be maintained in respect of the depth of water the nip of the press roll and felt during normal operating conditions.

Although the flow rates of water into the sue-- tion pipes 33 taken as an entirety, and into the nozzle through the inlet opening 2i is approzrimately the same, it should be observed that the flow in the pipes 33 will be much greater than the velocity of the water flow through the relatively large nozzle intake opening 2i. The high velocity of the water flow in the suction pipes 33 tends to prevent plugging of said pipes by the lodging of water-carried solid material around the inlet openings of said pipes. The

mea e99 relatively large size of the opening 2 in the accurate adjustment-of the water removing effect of the slice to permit maintenance of a substantially constant water pool the hip and in and around the mouth-endpor'tion of the nozzle of the slice. 7

Accordingly it has been found practicable to maintain only a small pool of water in the nip but one which is nevertheless sufficient to maintain the suction pipe in-lets immersed so as to prevent objectionable air sucking. The suction applied may be adjusted by suitable valve means (not shown) in the suction line leading to the slice. By adjustment of the suction, the amount of water permitted to collect in front of the press rolls and in thermouth edge portion of the slice may be effectively regulated.

The described vacuum slice may be employed in association with both the baby and main press rolls of a paper machine or at any point in a paper machine or like apparatus Where water tends to accumulate on a surface. In an experimental installation of a vacuum slice embodying substantially the construction shown, on a cylinder paperboard mill, it was possible to increase the speed of paper production from about eighty-seven feet per minute to about one hundred fifty feet per minute Without adversely affecting the characteristics of the paper web produced. The accelerated removal of water may be effected without changing the pressure of the press rolls on the paper web carrying felts, and good results may be attained even if the pressure is reduced somewhat. However, because of the decreased amount of water remaining in the sheet of paper and in the supporting felts, the press roll pressure may actually be increased Without causing crushing of the rather fluid paper web. By improved removal of the water (called white water in the trade) the felts are kept cleaner and the life thereof is greatly extended. By the improved removal of water, the drier section of the paper machine is relieved of a considerable portion of its normal work so that substantial economies are possible in the operation of the drier section.

To facilitate adjustment of the slice toward and from the nip of the press rolls, the side members 45 and I6 may be slotted as shown at 35 to slidably fit on the hanger rod 1. Side plates 36 and 31 are provided With bearing bosses 38 which fit on the rod 1. These plates 36 and 37 are adjustably attached to said frame sides !5 and It by means such as pairs of bolts 39 which pass through slots 48 in the plates and are threaded into the frame sides l5 and I8. The pressure controlling bolts 9 are attached at I 0, as aforesaid, to a lug which is attached to the side plates 36 and 37. The slice structure is thus adjustits side plates 36 and 37, the bolts 39 serving when tightened to lock the structure in selected position of adjustment. Certain of pipe will serve to flush out the main pipe 3] and some will be diverted through the branch pipes 3'3 to clean the same. Other openings may be provided, if desired, to afford access to the charm The various parts erably made of no the plane of the felt.

In some installations, means may be provided for counterbalancing the weight of the slice to facilitate adjustment thereof in extremely small increments and to support the slice in very light, readily yielding frictional engagement with the felt. The mounting and supporting arrangement may, of course, be varied l. A vacuum slice for withdrawing water from the nip closely approach said intake opening, the combined intake area of the inlet ends of all of said suction pipes being substantially less than the area of said nozzle intake opening, said nozzle being provided with a substantially rigid, smooth-surfaced bottom part adapted to tightly engage the felt across the entire width thereof to substantially prevent water leakage between said nozzle and the felt, and means for maintaining said bottom part of the nozzle tightly engaged with the felt as aforesaid.

2. A vacuum slice for withdrawing water from the nip formed between the upper roll of a pair of press rolls and the upper felt of a pair of felts which carry a wet paper web between such press rolls to enable the latter to squeeze water out of the web and felts, said slice comprising a nozzle adapted to be positioned so as to project into such a nip and having an elongated slot-like intake opening, the nozzle being of a width to extend across substantially the entire widths of such felts and having end walls adapted to be substantially aligned with the edges of said felts, and said nozzle having an upturned lip which serves as a baffle to prevent water from flowing over the top of the nozzle, a suction manifold associated with said nozzle and adapted to be connected to a source of suction, a plurality of suction pipes connected to said manifold and having inlet ends disposed within said nozzle in spaced relation to each other across the width of said nozzle, said suction pipes having inlet ends adjacent said intake opening of the nozzle, said inlet ends being flattened to permit said inlet ends to closely approach said intake opening, the combined intake area of the inlet ends of all of said suction pipes being substantially less than the area of said nozzle intake opening, said nozzle being provided with a substantially rigid, smooth-surfaced bottom part adapted to tightly engage the felt across the entire width thereof to substantially prevent water leakage between said nozzle and the felt, and yieldable means for maintaining said bottom part of the nozzle tightly engaged with the felt as aforesaid.

References Cited in the file of this patent UNITED STATES PATENTS Number Number Name Date Savery Sept. 2'7, 1898 Millspaugh May 17, 1910 Coppage Feb. 1, 1916 Johnson Apr. 19, 1921 Cramer July 18, 1922 Kutter May 20, 1924 Severini July 15, 1930 Sinclair July 14, 1931 Berry June 15, 1937 Hornbostel July 11, 1939 Worden June 15, 1948 Haubecky Dec. 26, 1950 FOREIGN PATENTS Country Date Great Britain July 10, 1939

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