US3160553A

US3160553A - Suction roll scavenging means

Info

Publication number: US3160553A
Application number: US213312A
Authority: US
Inventors: Donald A Ely
Original assignee: Beloit Corp
Current assignee: Beloit Corp
Priority date: 1962-07-30
Filing date: 1962-07-30
Publication date: 1964-12-08
Anticipated expiration: 1981-12-08

Description

Dec. 8, 1964 ELY SUCTION ROLL SCAVENGING MEANS Filed July 30, 1962 INVENTOR. Dona/a A. E/y

BY 2%. a

ATTORNEYS 3,160,553 SUCTIGN RGLL ESCAVENGENG MEANS Bonaid A. Ely, Beioit, Wis assignor to Beloit (lei-porntion, Beloit, Win, a corporation of Wisconsin Filed July 3%, 1962, Ser. No. 213,312 4 (Ilaims. {CL 162-274} The present invention relates to improvements in paper machines and more particularly to an improved mecha nism for removing water from a rotating roll such as a perforated suction roll.

In various locations on paper machines drilled suction rolls are employed and the holes in the roll receive water in the performance of their appointed function in the machine. This water must be removed during rotation. An example is the suction roll in a press nip wherein a drilled suction roll is used, and the holes receive water in the nip and some water collects on the surface of the roll which must be removed from the roll at a location after the nip so that the holes and surface are clear before again entering the nip.

It has heretofore been proposed to use such items as foils or scrapers in nip defining relationship with the suction roll to remove the excess water therefrom. The scrapers or foils tend to force water into the holes as it is removed from the land areas between the holes. Another proposed method is to use a pressure gland within the suction roll shell to blow the remaining water out of the suction shell holes. The pressure gland removes the water from the holes but tends to ignore the land area. A combination of the two is impractical, and other methods employed have met with disadvantages.

It is accordingly an object of the present invention to provide an improved mechanism for removing water from the rotating roll which receives water during operation.

A further object of the invention is to provide an improved mechanism for the effective removal of water from both the openings and the land areas tncrebetween of a perforate suction roll.

A feature of the invention is the provision of a suction roll scavenging means for a rotatable perforate roll receiving liquid during operation having a scavenging roll in close running relation to the perforate roll such as to form a narrow gap of uniform width therebetween forming a scavenging nip, and driving the scavenging roll in an opposite direction of rotation than the perforate roll so that the surfaces at the nip travel in the same direction, and preferably driving the scavenging roll at a higher surface speed and employing a relatively small scavenging roll so that water is effectively removed from the openings in the perforate roll and from the surface thereof. A saveall enclosure is provided enclosing the major portion of the perforate roll and the scavenging roll for receiving the removed water.

Other objects, advantages and features will become more apparent with the teachings of the principles of the invention in connection with the disclosure of the preferred embodiment thereof in the specification, claims and drawings, in which:

FIGURE 1 is a schematic front elevational view shown partially in section and taken from the end of a section of a paper machine having a suction roll scavenging means constructed and operating in accordance with the principles of the present invention;

FIGURE 2 is a schematic fragmentary side elevational view showing another arrangement; and

FIGURE 3 is a schematic fragmentary front elevational view similar to FIGURE 1 illustrating a further arrangement.

As shown on the drawings:

The features of the invention are illustrated as being embodied in a two roll press couple. The press con- United States Patent f 3,15%,553 Patented Dec. 8, 1984 sists of a plain top roll 1 and a perforate drilled suction roll 2 which is in the form of a shell. A suction box 3 is provided within the shell having suitable suction and drainage means of conventional design, which need not be shown.

The press rolls 1 and 2 define a press nip N therebetween through which runs a press felt 4 supporting a paper web 5. The press felt 4 is supported on

guide rolls

6 and 7 and is formed in a loop.

As is known from conventional operation, as the web 5 and the felt 4 pass through the nip N water is pressed from the web 5 into the felt, and the suction box 3 draws water from the felt into the drilled perforations 4. Some water is of course thrown off of the surface of the roll 2 by a centrifugal action but a certain amount adheres to the surface and is retained within the holes in the roll 2 due to surface tension. The water which is thrown off is gathered by a saveall enclosure it? provided with suitable drainage means.

Positioned adjacent the surface of the roll 2 after it leaves the press nip N is a scavenging roll 8. The scavenging roll is shown as positioned beneath the perforate roll 2 and forms a scavenging nip N therewith. The scavenging roll 8 is driven by a suitable drive means illustrated in the form of a motor J, preferably at a higher surface speed than the perforate roll 2. On the oifgoing side of the nip N the suction roll is evacuated from air and water on its circumference and within the holes. The water is sucked from within the holes and the surface of the perforate roll 2 and is thrown out outwardly as illustrated to be caught by the saveall pan 10.

The scavenging roll is positioned parallel to the perforate roll 2 and preferably is positioned to obtain a narrow gap between the scavenging roll 8 and the suction roll 2. The nip opening or gap is uniform along the length of the rolls for a uniform water removal effect.

In some structures the suction roll is heavily crowned, as illustrated in FIGURE 2 by the suction roll 12. In such event, a scavenging roll 13 may be used which is formed with a concave surface to form a nip N of uniform width.

Another method of operation is to slightly force the scavenging roll 8 against the suction roll 2, as illustrated in FIGURE 3. Suitable pressure applying means shown schematically at 11 may be employed so that the nip N is closed. The water film on the surface of the suction roll is adequate to provide for the necessary lubricant. In the event that a closed nip is used as illustrated in FIGURE 3, the scavenging roll 8 may be of the Mount Hope type. In each of the arrangements of FIGURES 1, 2 and 3, with an open nip such as shown in FIGURES 1 and 2, or closed nip such as shown in FIGURE 3, the scavenging roll is maintained in what may be termed close running relationship with the surface of the suction roll 2 to provide an effective removal of water from the holes and from the surface of the suction roll.

In summary, in the present arrangement a high speed rotating scavenging roll is provided positioned in close running relation to the roll to be dewatered, and in driving the scavenging roll at a high speed a substantial vacuum at the outgoing side of the nip is provided which effectively removes the water and throws it into the surrounding saveall pan 10.

While the use of the mechanism has been described in connection with a suction press roll, it will be understood that the principles of the invention may be applied to any roll in a paper machine which is constantly in contact with Water. For example the invention may be employed with a suction couch roll on a Fourdrinier, or to a plain or suction breast roll. Suction rolls of felt presses may also e constructed in accordance with the principles described.

The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. In a roll assembly including a rotatable roll having water receiving recesses in the surface receiving water during operation, a roll scavenging means comprising, a scavenging roll parallel to said rotatable roll and in close running relation thereto forming a scavenging nip therebetween, and drive means separate from the rotatable roll positively driving said scavenging roll in a rotational direction opposite to the rotatable roll at a positive periph eral speed independent of the speed of the rotatable roll so that the surfaces will travel in the same direction in the nip.

2. In a roll assembly including a rotatable roll having water receiving recesses in the surface receiving water during operation, a roll scavenging means comprising, a scavenging roll in close running relation to the rotatable roll and forming a scavenging nip therebetween, and drive means separate from the rotatable roll for driving said scavenging roll at a faster peripheral speed than the rotatable roll and in a rotational direction opposite to the rotatable roll so that the surfaces will travel in the same direction in the nip.

3. In a roll assembly including a rotatable roll having water receiving recesses in the surface receiving water during operation, a roll scavenging means comprising, a scavenging roll parallel to said rotatable roll and spaced therefrom to form a narrow gap of uniform Width therebetween forming a scavenging nip, and drive means separate from the rotatable roll for driving said scavenging roll in a rotational direction opposite to the rotatable roll so that the surfaces will travel in the same direction in the 4. In a press comprising a pair of press rolls forming a nip therebetween for receiving a felt carrying a paper web, one of said rolls having water receiving recesses, the combination comprising, a scavenging roll in close running relation to the recessed roll and forming a scavenging nip therebetween, drive means separate from the recessed roll for driving said scavenging roll at a faster peripheral speed than the recessed roll and in a rotational direction opposite to the recessed roll so that the surfaces will travel in the same direction in the nip, and a saveall enclosure enclosing the scavenging roll and a major portion of the recessed roll for receiving and draining liquid removed from the recessed roll.

References Cited in the file of this patent UNITED STATES PATENTS 1,934,543 Johnson Nov. 7, 1933

Claims

1. IN A ROLL ASSEMBLY INCLUDING A ROTATABLE ROLL HAVING WATER RECEIVING RECESSES IN THE SURFACERECEIVING WATER DURING OPERATION, A ROLL SCAVENGING MEANS COMPRISING, A SCAVENGING ROLL PARALLEL TO SAID ROTATABLE ROLL AND IN CLOSE RUNNING RELATION THERETO FORMING A SCAVENGING NIP THEREBETWEEN, AND DRIVE MEANS SEPARATE FROM THE ROTATABLE ROLL POSITIVELY DRIVING SAID SCAVENGING ROLL IN A ROTATIONAL DIRECTION OPPOSITE TO THE ROTATABLE ROLL AT A POSITIVE PERIPHERAL SPEED INDEPENDENT OF THE SPEED OF THE ROTATABLE ROLL SO THAT THE SURFACES WILL TRAVEL IN THE SAME DIRECTION IN THE NIP.