GB2036889A

GB2036889A - Sealing

Info

Publication number: GB2036889A
Application number: GB7938249A
Authority: GB
Original assignee: Rieter Werke Haendle GmbH
Current assignee: Rieter Werke Haendle GmbH
Priority date: 1978-11-06
Filing date: 1979-11-05
Publication date: 1980-07-02
Also published as: BE879805A; DD147085A5; GB2036889B; FR2440503A1; IT7969156A0; DE2942841A1; SE7908873L; DE7930011U1

Abstract

A conveyor mechanism for a pasty mass has a conveying drum 2 rotatably mounted in a housing 8 and whose end is sealed with respect to the housing 8. The sealing is effected via a labyrinth seal 18 and radial sealing faces of sealing flange 26 and ring 30. Arranged between the labyrinth seal 18 and the sealing faces is an annular channel 20 for the return of leaked mass to the inlet side of the conveyor mechanism. To improve the sealing outwardly, one sealing face 28 is connected via sealing ring 30 to a radially aligned supporting face 34 of a thrust ring 32 prestressed by means of a pressing device 36 between the conveying member 2 and the housing. A lubricating device 38 is provided for supplying lubricant to the sealing faces. The pressing device may comprise piston-cylinder units or springs. <IMAGE>

Description

SPECIFICATION Improvements in Sealing Devices for Pasty Mass Conveyors The invention is concerned with a sealing device in a conveyor mechanism for pasty masses, particularly but not exclusively, for clay or clay-like materials.

A sealing device of this kind is disclosed, for example, in CH-PS 533,007, the conveyor in this case being designed as a drum press. With such conveyor mechanisms the difficulty arises that the masses to be conveyed, especially when clay or clay-like material is concerned, can penetrate into the sealing faces where they lead to considerable wear, so that the seals become ineffective very quickly. Not only can leaked masses thereby be forced outwardly, but a pressure loss is produced within the conveyor mechanism.

The object of the invention is to provide such a conveyor mechanism with a sealing device which does not have the above-mentioned disadvantages.

According to the invention there is provided a conveyor mechanism for a pasty mass, comprising a conveying member rotatably mounted in a housing whose end is sealed with respect to the housing by means of a sealing device including a labyrinth seal and a sliding seal, there being disposed between the labyrinth seal and the sliding seal an annular channel for returning leaked mass to the inlet side of the conveyor mechanism, wherein the sealing faces of the sliding seal are radially aligned and are urged together by means of a thrust ring stressed by means of a pressing device disposed between the conveying member and the housing, and including a lubricating device adapted to supply lubricant to the sealing faces.

It has been discovered that the sealing effect can be substantially improved in a surprising way if the sliding seal is compressed by means of the pressing device and is lubricated. The pasty mass is thereby largely prevented from being able to penetrate into the sealing faces. The lubricant supplied via the lubricating device serves, on the one hand, to reduce friction between the sealing faces and, on the other hand, further to improve the sealing action. In so doing, the supply of lubricant is preferably adjusted so that a small quantity of lubricant penetrates into the annular channel between the labyrinth packing and the sealing faces. There consequently results a sealing device which not only is especially efficient, but also has a long service life.

The pressing device may comprise a plurality of compression springs which are distributed over the periphery of the thrust ring. This makes for quite a simple construction. However it is preferred that the pressing device comprises a plurality of piston-cylinder units actuated by pressure medium which are distributed over the periphery of the thrust ring, since it permits not only a more sensitive adjustment of the contact pressure, but also a readjustment of the thrust ring in dependence on the wear, while simultaneously maintaining the desired contact pressure. In both cases the contact pressure of the pressing device is preferably adjustable.

The lubricating device may be adapted for the supply of liquid lubricant, but preferably for the supply of pasty lubricant, since the latter results in a more efficient sealing. It is possible to supply the lubricant without especial excess pressure, notably when a liquid lubricant is concerned.

However, the supply of lubricant under pressure by means of a pressure generator is more advantageous.

The lubricant may be supplied, for example, radially from outside. However, it is preferred that the lubricating device includes at least one delivery line which passes through the thrust ring substantially perpendicularly to the sealing faces, since the lubricant thereby arrives directly at the faces adjacent one another.

The sealing device is suitable for the most diverse conveyor mechanisms, that is, for example, for screw pressures, drum presses and the like. Also, the sealing device for conveyor mechanisms is suitable for pasty masses of the most diverse types. However, especially advantageous is a construction and arrangement of the sealing device on a conveyor mechanism for clay or clay-like materials.

An embodiment of the conveyor mechanism with sealing device according to the invention will now be described in detail with reference to the accompanying drawing which shows an end of a conveyor mechanism in vertical (axial) section.

The-conveyor mechanism shown in the Figure contains a conveying member 3 designed as a conveying drum and provided with continuous ribs 4 forming between them annular spaces 6 in which the mass to be conveyed is carried along.

The conveying member 2 lies in a housing 8 and is mounted in a bearing 12 via a stub shaft 10.

The conveying space 14 in which the pasty mass is conveyed is sealed outwardly via a sealing device 16.

The sealing device 1 6 has firstly a labyrinth seal 18 which leads into an annular channel 20 serving for the return of leaked mass. Said leaked mass is supplied via a scraper 22 to the inlet side 24 of the conveyor mechanism. The labyrinth seal is designed so that practically no excess pressure is present in the annular channel 20, so that the leaked mass can be returned without pressure to the inlet side of the conveyor mechanism. The annular channel 20 is closed on the side remote from the conveying member by a radial flange 26 which forms on the outside a radial sealing face 28 on which a sealing ring 30 abuts. This sealing ring 30 is urged against the radial sealing face 28 by means of a thrust ring 32 which has a radial supporting face 34 and which is mounted in the housing and optionally screwed thereto. Three piston-cylinder units 36 arranged about the periphery of the thrust ring 32 generate the necessary contact pressure for the thrust ring 32.

A hydraulic pressure medium may be used which stands, for example, under the pressure of 10 bars.

The sealing device 1 6 also has a lubricating device 38 containing a delivery line 40 which extends through the thrust ring 32 and the sealing ring 30 up to the inner radial sealing face 28. For example, a lubricating grease may be supplied periodically or preferably continuously with the lubricating device, whereby the pressure may amount, for example, to 50 bars. As a result, one delivery line 40 is sufficient, but several delivery lines distributed around the periphery may optionally be provided.

Claims

1. A conveyor mechanism for a pasty mass, comprising a conveying member rotatably mounted in a housing whose end is sealed with respect to the housing by means of a sealing device including a labyrinth seal and a sliding seal, there being disposed between the labyrinth seal and the sliding seal an annular channel for returning leaked mass to the inlet side of the conveyor mechanism, wherein the sealing faces of the sliding seal are radially aligned and are urged together by means of a thrust ring stressed by means of a pressing device disposed between the conveying member and the housing, and including a lubricating device adapted to supply lubricant to the sealing faces.

2. A conveyor mechanism according to claim 1, in which the pressing device comprises a plurality of piston-cylinder units actuated by pressure medium which are distributed over the periphery of the thrust ring.

3. A conveyor mechanism according to claim 1, in which the pressing device comprises a plurality of compression springs which are distributed over the periphery of the thrust ring.

4. A conveying mechanism according to claim 2 or 3 in which the contact pressure of the pressing device is adjustable.

5. A conveyor mechanism according to any of the preceding claims in which the lubricating device is adapted for the supply of liquid lubricant.

6. A conveyor mechanism according to any of claims 1 to 4, in which the lubricating device is adapted for the supply of pasty lubricant.

7. A conveyor mechanism according to any of the preceding claims in which the lubricating device includes a pressure generator to supply the lubricant under pressure.

8. A conveyor mechanism according to any of the preceding claims in which the lubricating device includes at least one delivery line which passes through the thrust ring substantially perpendicularly to the sealing faces.

9. A conveyor mechanism for a pasty mass including a sealing device substantially as hereinbefore described with reference to the accompanying drawings.