US2696148A - Combined fluid pressure and suction press - Google Patents

Description

Dec. 7, 1954 L. HORNBOSTEL COMBINED FLUID PRESSURE AND SUCTION PRESS Filed Jan. 7, 1950 mmxVllll United States Patent COIVIBINED FLUID PRESSURE AND SUCTION I PRESS Lloyd Hornbostel, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Application January 7, 1950, Serial No. 137,378

7 Claims. (CI. 92-49) The present invention relates to a combined fluid pressure and suction press and more particularly to a paper machine press in which fluid under pressure is employed to aid a conventional suction arrangement for removing water from a moist paper Web.

Various types of suction presses have long been used in paper machines. However, in such presses moisture removal from the wet web has been limited by the degree of vacuum to which the web may be subjected.

The present invention now provides an improved combined fluid pressure and suction press in which the fluid pressure area is confined to the nip of the press and lies within the suction area. The fluid under pressure, such as air or other gas, acts directly against the suction area of the press, so that the most favorable conditions for etficient water removal are present at the nip. In addition, the suction roll of the press is provided with a resilient cover or peripheral coating so that an effective fluid seal is formed at the press nip by deformation of the suction roll, this deformation also providing an enlarged nip area adapted to directly receive fluid under pressure. In this manner, it is possible to effectively employ the combined fluid pressure at the press nip in order to insure eflective water removal from the moist web.

It is, therefore, an important object of the present invention to provide an improved combined fluid pressure and suction press for a paper making machine.

Another important object of the present invention is to provide a paper machine press in which fluid under pressure and suction are employed in combination at the press nip to effectively remove moisture from a wet paper web.

It is another important object of the present invention to provide an improved press for a paper making machine including a plurality of press rolls defining a pressure nip and provided with means for subjecting the moist Web to cooperating fluid pressure and suction at the press nip to aid in the'removal pressure from the wet web.

Still another important object of the present invention is to provide a paper machine press including a suction roll having a resilient peripheral covering and an interior suction gland, and a superimposed roll cooperating with the suction roll to define a press nip and having means for subjecting the paper web passing through the nip to fluid under pressure to aid the suction roll in removing moisture from the web.

Other and further improvement objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

On the drawings:

Figure 1 is a schematic side elevational view of a combined fluid pressure and suction press of the present invention;

Figure 2 is a greatly enlarged radial sectional view of the nip of the press of Figure 1; and

Figure 3 is a greatly enlarged sectional view, similar to Figure 2, of a modified form of combined press of the present invention.

On the drawings:

In Figure 1, reference numeral refers generally to a combined fluid pressure and suction press of the present invention.

The press assembly 10 comprises an upper roll 11 and a lower roll 12 journaled for rotation about parallel longitudinal axes and cooperating to define therebetween a restricted pressure nip 13. The nip 13 receives therethrough a press felt 14 carrying on its upper surface a moist paper web 15.

As best shown in Figure 2, the rolls 11 and 12 are in pressure contact and cooperate to remove water from the moist web 15. The lower roll 12 is a conventional suction roll which is provided with a suction gland 16 of conventional design, the gland terminating in spaced arms 16a carrying packing strips 17 contacting the inner periphery 18 of a rotatable, cylindrical, perforated suction drum or shell 19. The drum 19 is provided with a peripheral resilient cover or sheath 20 formed of rubber or the like material, the sheath 20 also having apertures therethrough communicating with the apertures of the drum 19.

The upper roll 11 has a gland 21 provided with spaced terminal arms 21a similar to the arms 16a hereinbefore defined, each of the arms carrying a terminal packing strip 22 which contacts the inner periphery 23 of a shell or drum 24 similar to the drum 19. The drum 24 also is provided with an enveloping sheath 25 of resilient material similar to the sheath 20 hereinbefore described.

Due to the pressure contact of the resilient sheaths Ztl and 25 of the drums 19 and 24 respectively, that portion of each of the sheaths at the pressure nip 13 is deformed so as to provide a relatively fiat pressure area 26. The gland 16 is adapted to be evacuated by suitable means as well understood in the art, and this vacuum is transmitted through the drum 19 and its sheath 20 to the pressure nip area 26 to withdraw moisture from the moist paper web 15. The gland 21 within the press roll 11 is adapted to receive fluid, such as air, dry steam, carbon dioxide, nitrogen, or other gaseous fluid under pressure and this pressure will likewise be exerted at the flattened pressure area 26. Thus increased superatmospheric fluid pressure is exerted on the upper surface of the web 15 and a reduced subatmospheric pressure is exerted upon the under surface of the web at the nip 13, with the porous press felt 14 offering little resistance to fluid pressure or vacuum. In this manner, more eflicient pressing action is obtained at the nip 13 and the dewatering of the web 15 is more efficient for this reason.

It will be noted that the area defined by the packing strips 22 is slightly less than the pressure nip area 26, in other words, the strips 22 lie within the limits of the nip area 26, so that there is no loss of air pressure at the nip. This prevention of pressure loss is the result of the registry of the perforations of the drum 24 and the sheath 25 with the flattened, effectively sealed pressure nip area 26 and with the vacuum area between the strips 17 at the pressure nip area 26. The pressure area between the packing strips 22 is also less than the suction area between the vacuum strips 17, so that in this manner all of the air under pressure from the gland of the upper roll 11 is ejected directly against the suction area of the lower roll 12, thus conserving fluid pressure. In addition, the resilient sheaths or envelopes 20 and 25 form a flattened area 26 and this area aids in effectively sealing both fluid pressure and vacuum at the nip. No vacuum is lost between the packing strips 17, inasmuch as the moist web 15 and the felt 14 completely lap the suction area of the lower roll 12.

In the embodiment of the present invention as shown in Figure 3, the lower roll 12 is substantially identical with that shown in Figure 1 of the drawings and like reference numerals refer to like portions of the apparatus. The upper roll 27 is also substantiallyidentical to the roll 11 hereinbefore described with the exception that the outer resilient sheath 25 of the roll 11 has been eliminated. Inasmuch as the hard surface of the upper roll 27 acts against the resilient surface of the under roll 12, a concavo convex suction area 28 is formed at the point of contact between the rolls. Thus, the hard surface upper roll 27 flattens a contact area of the resilient sheath 20 of the under roll 12 to form a pressure area corresponding to the area 26 hereinbefore described with the attendant advantages of fluid pressure sealing, enlarged pressure contact area, etc.

From the foregoing description, it will be appreciated that the present invention provides a novel form of combined pressure and suction press which is effective to remove larger quantities of moisture from a wet paper web than has been heretofore possible by the employment of a combined suction press. The present invention directs fluid under pressure against the web within the limits of the pressure nip of the press, and the combined fluid pressure and suction effect exerted upon the web results in improved moisture removal. Further, fluid pressure is not wasted but is exerted directly against the suction area at the nip with all of the fluid under pressure being directed into the suction area. The employment of a suction roll having a resilient peripheral sheet provides a flattened pressure nip having a relatively large pressure area, while at the same time providing an effective fluid seal.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

1 claim as my invention:

.1. A paper machine press for removing moisture from wet paper webs comprising a pair of cooperating press rolls defining a pressure nip therebetween having a limited circumferential dimension, oneof said rolls having a resilient peripheral covering thereon which is deformed radially of said one roll throughout the circumferential dimension at said nip, and opposing suction and gaseous fluid superatmospheric pressure means carried by said rolls at said nip for generating a differential fluid pressure exerted against said web passing therethrough with the deformed portion of said one roll providing a fluid tight seal at said nip, the superatmospheric pressure means being limited to the circumferential dimension of the nip.

2. A fluid pressure and suction press comprising upper and lower press rolls defining therebetween a pressure nip, a suction gland in one of said rolls, means for evacuat ing said suction gland to subject said nip to a diminished fluid pressure, a pressure gland in the other of said rolls for forming an opposing superatmospheric pressure area at said nip, said pressure area being confined to said nip and smaller than said suction area, and means for introducing gaseous fluid under superatmospheric pressure to said pressure gland, whereby a moist paper web passing through said pressure nip is subjected to a differential fluid pressure which is the aggregate of the vacuum in said suction gland and superatmospheric fluid pressure in said pressure gland.

3. A combined fluid pressure and suction press comprising a lower press roll having a rotatable perforated shell and means defining a suction area at the inner periphery of said shell, and an upper press roll having a rotatable perforated shell and means defining a superatmospheric gaseous fluid pressure area at the interior periphery thereof, each of said areas traversing the pressure nip between said rolls and said pressure area being confined to the pressure nip in directly opposed relation to said suction area, said pressure area being entirely encompassed within said suction area, and both of said areas coacting to subject a moist paper web passing through the nip to a differential gaseous fluid pressure effective to remove water therefrom through said suction area.

4. A combined fluid pressure and suction press com prising upper and lower press rolls defining therebetween a pressure nip, said upper roll including a rotatable radially perforated shell, means for introducing gaseous fluid under superatmospheric pressure to the interior of said shell, and means for confining gas fluid under superatmospheric pressure escaping through the periphery of said shell to the area of said nip, and said lower roll including a rotatable radially perforated shell, a resilient perforated cover for said shell, means for evacuating the interior of said shell, and means defining a suction area at the inner periphery of said shell at said nip and in advance thereof, said suction area covering a greater nip area than said pressure area of said upper roll and the resilient envelope of said lower roll being deformed by nip contact with said upper roll to define an enlarged fluid sealed nip area at which substantially all of the gaseous .fluid under superatmospheric pressure from said pressure area is directed into, said suction area.

5. A combined fluid pressure and suction press comprising an upper rotatable perforate shell, a perforate resilient cover enclosing said upper shell, means for introducing gaseous fluid under superatmospheric pressure into the interior of said upper shell, means confining the superatmospheric gaseous fluid pressure to a relatively small pressure area at the inner periphery of said upper shell, a lower rotatable perforate shell, ,a resilient perforate cover enclosing said lower shell, means for evacuat ing the interior of said lower shell, and means for confining the evacuation of ,said lower shell to a relatively small portion thereof, said shells cooperating to define a pressure nip therebetween at which said resilient covers are each deformed radially of said shells to define an enlarged flattened gaseous fluid sealed pressure nip through which fluid under superatmospheric pressure within said first shell is directed and from which .the evacuated area of said lower shell receives the gaseous filllllldl under superatmospheric pressure from said upper s e 6. A combined fluid pressure and suction press for a paper making machine comprising a pair of cooperating suction press rolls defining a pressure nip therebetween, each of said rolls having a resilient peripheral cover, pressure contact of said rolls at said nip deforming said covers radially to provide aflattened enlarged fluid pressure sealed nip area, a suction area within the lower of said rolls at said nip and immediately in advance thereof, and means in the other of said rolls for directing a gaseous fluid under superatmospheric pressure at said nip in opposed relation to the suction area of said lower roll, said gaseous fluid under superatmospheric pressure being directed against said web solely at said nip and being totally confined within the suction area of the lower roll.

7. A combined fluid pressure and suction press for a paper making machine .c'omprisinga pair of suction press rolls having radial perforations and defining a pressure nip therebetween, one of said .rolls having a resilient perforated peripheral cover which is flattened by pressure contact with said other roll at said nip, means in one of said rolls forexerting suction through its perforations at the nip and in advance thereof on a web trained through said nip, a source of gas under superatmospheric pressure, and means communicating with said source in the other of said rolls for directing the gas under superatmospheric pressure against ,said web .at said nip, said gas under superatmospheric pressure being directed against said web through only those perforations of said other roll which register with the flattened portion of said cover, said gas under superatmospheric pressure thus being totally confined within the suction area of the one roll.

References Cited in the file-0f this patent UNITED STATES PATENTS Number Name Date 266,307 Parent .Oct. 24, 1882 689,400 Keeney Dec. 24, 1901 1,701,226 Collins Feb. 5, 1929 2,144,770 Millspaugh Jan. 24, 1939 2,174,744 Hill Oct. 3, 1939 2,288,675 Berry July 7, 1942 2,441,169 Roman May 11, 1948 FOREIGN PATENTS Number Country Date 170,871 Great Britain Oct. 31, 1921

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