US 5,688,375 AGranted

Shoe press roll for a paper machine

AssigneeVoith Sulzer Papiermaschinen GmbH

InventorChristian Schiel

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Abstract

A shoe press roll for a paper machine which, together with a backing roll, forms a press nip through which a press jacket guided over the shoe press roll travels together with a paper web. The shoe press roll comprises a press shoe which can be pressed by at least one hydraulic element against the backing roll. The hydraulic element is developed as a cylinder/piston unit that acts between a stationary support member and the press shoe. The unit includes a first pressure chamber which can be acted on by hydraulic pressure and is in communication via a small diameter throttle point passing through the piston with a second pressure chamber which is open toward the press shoe. The edge of the piston rests with a sealing surface against the press shoe. Hydraulic pressure is transmitted from the first pressure chamber under approximately static conditions, to the second pressure chamber through the throttle point and thus to the press shoe. Should the press shoe tilt permitting pressure to escape from the second chamber at the shoe, the throttle point prevents rapid continuous flow of hydraulic pressure out of the first pressure chamber. The tilting produces a pressure drop in the second pressure chamber which causes the press shoe to apply itself against the cylinder/piston unit as a result of the external pressure applied from the first pressure chamber.

Claims20

Dependent claims

A shoe press roll for a paper machine, wherein the shoe press roll cooperates with a backing roll to form a press nip through which pass a press jacket on which a web to be dewatered is supported as they travel together through the press nip when the backing roll rotates through the press nip and the press jacket moves through the press nip, the shoe press roll comprising:

a stationary support with a cylinder defined therein opening radially outward toward the press nip and the backing roll;
a press shoe located toward the radial outside of the cylinder, the shoe having an outward surface toward the backing roll which defines the press nip with the backing roll and having an inward surface facing toward the cylinder;
a piston located in the cylinder, the piston having first and second sides below and above the piston, respectively, and the piston being sealingly movable along the cylinder toward and away from the backing roll;
a first pressure chamber in the cylinder below the first side of the piston away from the press shoe, and means for communicating hydraulic pressure to the first pressure chamber;
the piston being shaped for defining a second pressure chamber above the second side of the piston toward the press shoe, the piston second side and the press shoe inward surface being normally cooperatingly shaped for sealing the second pressure chamber;
and
a passage from the first pressure chamber to the second pressure chamber, the passage having a cross section sized for defining a throttle point for permitting throttled passage of hydraulic pressure from the first pressure chamber to the second pressure chamber, the passage having a cross section for preventing a rapid reduction of pressure in the first pressure chamber, occurring by a sudden reduction of pressure in the second pressure chamber, thereby permitting continued urging of the piston toward its sealing position against the press shoe for sealing the second pressure chamber.

4 more elements

A shoe press roll for a paper machine, wherein the shoe press roll cooperates with a backing roll to form a press nip through which pass a press jacket on which a web to be dewatered are supported as they travel together through the press nip when the backing roll rotates through the press nip and the press jacket moves through the press nip, the shoe press roll comprising:

a press shoe for being urged toward the backing roll;
a stationary support member;
a hydraulic element developed as a cylinder/piston unit located between the stationary support member and the press shoe, the cylinder/piston unit comprising:
a first pressure chamber, and means for delivering hydraulic pressure to the first pressure chamber;
a second pressure chamber which is open toward the press shoe and edge means defining an edge around the second pressure chamber, the edge means resting sealingly against the press shoe;
a passage having a cross section sized for defining a hydraulic pressure throttle point communicating between the first and second pressure chambers, and the passage being sized so that a reduction in the pressure in the second pressure chamber with reference to the pressure in the first pressure chamber does not cause an immediate reduction in the pressure in the first pressure chamber.

3 more elements

Dependencies are inferred from the claim text.