FI120419B - An arrangement for controlling the loading pressure of a shoe roll - Google Patents

Description

An arrangement for controlling the loading pressure of a shoe roll

The present invention relates to material web machines such as fiber web machines, such as various paper machines, pulp machines, board machines. More particularly, the present invention relates to a stiffening device for controlling the loading pressure of a shoe roll, the roll casing being subjected to a succession of internally loaded cylinders and / or parallel loading cylinders with a pressurized loading cylinder with successively loaded loading cylinders.

U.S. Patent No. 5,980,438 discloses a deflection control of a deflection compensated roll, wherein the pressurizing chamber of the roll shell loading cylinder being loaded with the pressurized medium communicates with the center passageway of the roll axis through successive spacings of the roll axes. From patent applications FI20001452 and EP 99850014.4 there are also known solutions for introducing a pressurized medium through the axis of a roll into a pressurizing chamber or pressurization chambers for controlling the loading pressure.

According to said US Patent No. 5,980438, for the quick release of the loading pressures of the loading cylinders or loading shoes, the interconnecting channel of each pressurized chamber may be associated with a pressurized fluid discharge channel communicating with a discharge valve disposed on the outer circumference of the deflection roller shaft. The actuation of the release valves is implemented in accordance with this US publication by a common control means which is moved in the axial direction of the roll 25 to simultaneously open and / or close the release valves. An essential problem with the prior art is that, in order to control the web, it must be possible to release the loading pressure of the roll very quickly, if necessary. Known roll tubing or boreholes do not achieve sufficiently rapid control of the loading pressure, in particular the quick release of the loading pressure of the loading cylinder in the shoe roll, since prior art arrangements have been developed for deflection compensated rolls with no discharge rate As a result of the problem, the slow release rate of the load pressure can cause the belt or felt, for example, to be damaged in the event of a web break.

2

In a shoe roll, a solution for deflecting a deflection compensated roll is not applicable, because on the one hand it is essential to achieve a rapid release pressure on the load and on the other hand there is no flow through the shoe roll cylinder.

It is an object of the present invention to eliminate or at least substantially reduce the problems of the prior art and to provide a novel inventive arrangement for controlling the loading pressure of a shoe roll. Another object of the present invention is to improve the rapid discharge of the loading pressures of the loading cylinders or loading shoes.

The objectives may generally be achieved by the above arrangement for controlling the loading pressure of a shoe roll, for example by accommodating a loading cylinder or parallel loading cylinders in a loading cylinder block provided with a pressurized fluid discharge valve communicating with the pressurizing medium of the loading cylinder.

15

According to a preferred embodiment of the invention, the discharge channel extends from the pressure chamber of the loading cylinder through the wall of the loading cylinder or the wall of the loading cylinder block and to the discharge valve. Preferably, each load cylinder block is provided with a separate discharge valve. The control of the discharge valve may be hydraulically arranged. It is preferred that the discharge valve is hydraulically biased. The discharge valve control and / or pilot control may also be implemented electrically and / or wirelessly

According to the invention, it is preferable that a separate discharge valve is provided for each group of loading cylinders in order to achieve a quick discharge operation. In this case, it is recommended that the pressure state of each load cylinder of each set of load cylinders is communicated via a separate discharge channel 25 to a common discharge valve, whereby all discharge valves operate simultaneously with a minimized delay.

For other aspects of the invention, reference is made to the appended claims.

The advantages of the invention may be further mentioned: • that the release force of the roll pair can be set to the same, which significantly saves the roller bearings, since the balance of power can be controlled during the unloading process; • that the loading pressure can be discharged directly into the shoe roll through the release valve; and 3 • that the discharge pressure can be quickly triggered by a common pre-control valve which can open all the discharge valves simultaneously, making the arrangement reliable and safe, whereby all the discharge valves can be controlled by a single pre-control valve with hydraulic, electrical and / or wireless control.

5

In the following specific part of the specification, the present invention will be described by way of two embodiments with reference to the accompanying drawing, in which FIG. 1 is a side and partial cross-sectional view of an inner loading shoe of a shoe roll which may be provided with the arrangement of the invention; and FIG. 3 shows an arrangement according to another embodiment of the invention

Referring to FIG. 1 is a side elevational and partial cross-sectional view of a shoe roll 10 having a casing 11 loaded by an inner loading shoe 12. The loading shoe is loaded by a loading cylinder 1, 2 consisting of cylinder 1 and piston 2 and having a pressure space or pressure chamber for receiving the pressurized fluid.

In order to load the diaper 11 by means of a concave loading shoe 12, the inner loading cylinders 1,2, or groups of parallel loading cylinders, are spaced in succession in the axial direction of the roll 10. The axial loading shoe 12 and its loading cylinder are arranged in a block 3 of the loading cylinder (s).

The loading pressure of the pressurizing chamber, i.e. the load cylinder 1, 2, can be rapidly discharged by a pressurized fluid discharge channel 4 and a discharge valve 5 arranged in the block 3 of the load cylinder (s) (cf. Figs. 2 and 3).

Referring to FIG. The loading cylinder block 3 comprising the loading cylinder 1, 2 is provided with a pressurized fluid discharge valve 5 which communicates with the pressures of the loading cylinder via the pressurized fluid discharge channel 4.

Thus, each load cylinder 1, 2 is provided with its own pressurized fluid discharge valve 5, to which the pressure cylinder pressure space is connected via a separate discharge channel 4. The pressurized medium can thus be discharged via the shortest possible path / path, i. from the pressure cylinder of the loading cylinder through the discharge channel and the discharge valve to the inside of the roll 10.

4

Referring to FIG. A loading cylinder block 3 comprising two parallel loading cylinders 1, 2 is provided with a pressurized fluid discharge valve 5 which communicates with the pressures of the loading cylinder via a pressurized fluid discharge channel 4.

Then, in each load cylinder block 3, the set of load cylinders 1, 2 has its own pressurized fluid discharge valve 5, and the pressures of each load cylinder of each set of load cylinders are connected via a separate discharge channel 4 to a common discharge valve. The pressurized medium can thus be discharged via the shortest possible path / path, i. the pressure space of the loading cylinder 10 through the discharge channel and discharge valve, inside the roll 10.

It is not essential to the invention how the discharge valve control is implemented, since various controls for the valves and / or the quick release / quick shutoff valves are known per se. Thus, for the sake of simplicity and clarity, it is noted that for the purpose of implementing the invention, the control of the discharge valve is provided hydraulically, whereby the discharge valve may be hydraulically pre-controlled. Alternatively, the control / pre-control of the discharge valve may be implemented as electrical control and / or wireless control may be applied.

The invention has been described above only by way of examples. This is, of course, not limited in any way to the present invention, but various alternative solutions and modifications as well as functionally equivalent solutions are possible within the scope of the appended claims.

Claims (10)

1. Arrangement for controlling loading pressure of a shoe roller (10), a sheath (11) of which the roller is loaded in a direction of the roller axis of internal load cylinders (1,2) arranged at a distance from each other and / or parallel load cylinders , to which the loading cylinder is connected to the pressing chamber of the loading cylinder to receive medium under pressure via an inlet channel of the intermediate pressure, characterized in that the loading cylinder (1,2) or the parallel loading cylinders (1,2) are arranged to a loading block (3). ), which is provided with a pressure relief valve (5) of medium under pressure, which discharge valve is connected to the pressure space of the load cylinder via at least one pressure relief channel (4) of medium. 2. Arrangement according to claim 1, characterized in that the relief duct (4) extends from the pressure chamber of the load cylinder through the wall of the load cylinder (1, 2) or the wall of the load cylinder block (3) to the relief cylinder (5). 3. Arrangement according to claims 1 and / or 2, characterized in that a separate relief valve (5) is arranged for each load cylinder block (3). 4. Arrangement according to claim 3, characterized in that the pressure space of each load cylinder (1, 2) of each load block (3) is connected via a separate relief channel (4) to a common relief valve (5). 5. Arrangement according to any of the preceding claims, characterized in that, under pressure, medium 25 releases the relief cylinders (1,2) via the relief channel (4) and the relief valve (5) into the roller (10). Arrangement according to any of the preceding claims, characterized in that the relief valve control is arranged hydraulically. 30 Arrangement according to claim 6, characterized in that the relief valve (5) is hydraulically controlled and / or controlled. Arrangement according to any of the preceding claims, characterized in that the control and / or pre-release of the relief valve (5) is electrical. 9. Arrangement according to any of the preceding claims, characterized in that the control and / or pre-relief of the relief valve (5) is a treeless control. Arrangement according to any of the preceding claims 7-9, characterized in that the pre-flow valve is common to all the relief valves (5). 10