WO1994003744A1

WO1994003744A1 - Sliding ring packing

Info

Publication number: WO1994003744A1
Application number: PCT/CZ1993/000018
Authority: WO
Inventors: Josef Strnad
Original assignee: Královopolská, A.S.
Priority date: 1992-08-03
Filing date: 1993-08-02
Publication date: 1994-02-17
Also published as: SK277917B6; PL307239A1; FI950471A; AU4557093A; EP0653031A1; HU9500339D0; SK240592A3; FI950471A0; HUT69576A; CZ240592A3; CA2140780A1; CZ278856B6

Abstract

A sliding ring packing between two parts, in particular a packing on the inlet part of a drum filter comprising a stationary packing ring (2) fixed to one of the parts and, pressed onto it, a moving ring (1) coupled with the other of the two parts. To the moving ring (1) is fixed one end of a resilient ring membrane (4) whose the other end is fixed between a guiding ring (8) and a supporting ring (6) between which is seated an overlapping resilient packing (9) providing for the pressure of the guiding ring (8) on the supporting ring (6).

Description

Sliding Ring Packing

Technical Field

The invention relates to a sliding ring packing between two parts, in particular to a packing on the inlet part of a drum filter comprising a stationary packin ring fixed to one of the parts and, pressed onto it, a moving ring coupled with the other of the two parts on which is fixed a su porting ring.

Background of the Invention

Sliding ring packings of large-diameter rotary surfaces are used for instance in drum filters serving for cleaning soiled waste water. In known drum filters, the soiled waste water is led into the inner space of the rotary drum filter whose lower part is in the filtered water, the level of the soiled waste water inside the drum of the drum filter being higher than the level of the filtered water outside the drum of the drum filter. The packing on the inlet part of the drum filter serves to prevent the unfiltered water outside the drum of the drum filter from getting into the space between the stationary and the rotary parts of the drum of the drum filter due to the hydrostatic pressure produced by the level difference inside and outside the drum of the drum filter. A typical feature of these sliding ring packings consists in the large diameter of the packed surface and in the risk of unwanted radial and axial movements of the rotary part of the drum filter due to inaccurate seating.

The heretofore known packing of the drum filter consists of a hose filled with water under adjustable pressure and seated between the stationary and the rotary part of the drum filter. The hose spreading provides for eliminating the gap between the stationary and the rotary parts of the drum filter. Even if the rubber hose can be replaced by a hose made of another elastic material, this packing is marked by low service life, unreliable working, increased need both to check its function and to carry out its maintenance. At the same time, this type of packing features high resistance against the rotation of the drum filter.

Another known sliding ring packing, described in US 4,854.598, is used in pumps for liquids. The packing comprises a ring made of a hard material and fixed in the moving wheel of the pump. Onto this ring made of a hard material is pressed a sliding ring made of a graphite-saturated resin by means of an axially acting spring. This packing is intended for small diameter packings and high rotation speeds.

The use of this design for drum filter packings is impossible, because the sliding ring would get worn-out in a very short time, and the packing would cease to fulfil its function due to the fact that the minimal pressure force of the spring must be adjusted for the minimal required pressure force at the maximal wear of the sliding ring, so that the pressure force is uselessly excessive for the sliding ring not yet worn out.

Disclosure of Invention

The above specified drawbacks of the state of art are removed by a sliding ring packing according to the invention comprising a stationary ring fixed to one of the parts and, pressed onto it, a moving ring coupled with the other of the two parts. The principle of the invention consists in that on the moving ring there is fixed one end of a resilient membrane whose other end is fixed between a supporting ring and a guiding ring between which is mounted an overlapping resilient packing providing for pushing the guiding ring to the supporting ring.

To improve the fixing of the resilient membrane between the supporting and the guiding ring and to improve the tightness of the sliding ring packing, the second end of the ring membrane is set on the guiding ring by means of which the resilient ring membrane is fixed on the supporting ring, said end of the resilient ring membrane being pressed by the resilient packing to the guiding ring.

The supporting ring can carry a torsion spring whose free end leans against the moving ring.

Brief Description of the Drawing

An example of embodiment of the sliding ring packing is shown in the accompanying drawing.

Modes for Carrying Out the Invention

The sliding ring packing of large-diameter rotary parts will be described on the example of embodiment of the sliding ring packing of the inlet part of a drum filter.

The drum filter comprises a stationary frame 3_ having a hole to let soiled water or another liquid to be filtered enter the inner space of the drum fil¬ ter. Around said hole and fixed to the stationary frame _3 is a stationary packing ring 2_ contacted by a moving ring 1 whose inner diameter is in the shown embodiment larger than the diameter of the hole of the stationary packing ring 2_. As the smallest suitable inner diameter of the moving ring _1_ may be taken the diameter of the hole of the stationary packing ring 2_ . The moving ring j_ is coupled with the face _7. °f a drum _5_ made as a ring disc which is a part of the supporting frame of the drum 5_ carrying and having fixed thereto well-known filter cloths through which passes and thus filters in well-known manner the soiled liquid passing during the filtering process into the space outside the drum _5 of the drum filter where it is collected and in a not represented well-known manner taken away.The diameter of the hole provided in the face 7_ of the drum 5_ is equal or superior to the inner diameter of the moving ring 1_. The level difference between the soiled liquid inside the drum _5_ and the filtered liquid outside the drum _5 provides for hydrostatic pressure indispensable for the working of the drum filter. However, at the same time, it is necessary to prevent the soiled liquid from entering the space outside the drum 5_ except the filter cloths which could occur between the face 7_ of the drum _5 and the moving ring 1_, and also between the moving ring 1_ and the stationary packing ring 2_ .

To the face 7_ of the drum _5 is fixed a shaped supporting ring 6 fitted on its rim with reinforcing bendings between which is in the shown example of embodiment provided a cylindrical part whose outward part can be used in a well-known way for embracing with a well-known, not represented supporting and driving means, for instance with a belt. Inside the supporting ring 6_^ is fixed a stop J_0 which can consist of a ring body fixed to the supporting ring _6, for instance by welding, or it can be made as one piece with the supporting ring 6_.

Fixed on the outward circumference of the moving ring J^, on the side adjacent the face 7_ of the drum 5_, is a resilient ring membrane 4_ whose free end is put on the inner end of the guiding ring JB inserted in the space inside a carrying ring b_. The inner diameter of the inner end of the guiding ring 8_ is superior to the outer diameter of the moving ring _1_ by more than four times the thickness of the resili¬ ent ring membrane 4.

The minimal length in which the resilient ring membrane h_ is put on the guiding ring 8_ is equal to the size of the contacting surface of the guiding ring 8_ on the stop 1_0 of the supporting ring 6_. Between the part of the outer surface of the guiding ring J3 and the part of the inner surface of the supporting ring 6_^ is inserted an overlapping resilient packing 9_ filling and packing the space between the guiding ring 8_^ and the supporting ring _. The inserted resili¬ ent packing 9_ serves also to fix the resilient ring membrane 4_ on the guiding ring 8_, the guiding ring 8_^ being pressed together with the resilient ring mem¬ brane 4_ to the stop 1_0 of the supporting ring 6_^.

Under the action of the hydrostatic pressure exerted from inside on the resilient ring membrane 4_ and due to the fixed connection of the membrane 4_ with the moving ring 1_, the moving ring _1_ is pressed onto the surface of the stationary packing ring 2_ made of abrasion resistant material. Due to this arran¬ gement, at sufficient length of the resilient membrane _ can the moving ring 1_ made of a known material con¬ taining graphite wear by as much as three quarters of its length without decreasing the packing effect. The pressure force acting on the moving ring J_ is not affected by the wear and can be therefore throughout set at the minimum. The pressure force acts on the moving ring _!_ even when the drum 5_ does no t r o ta te .

As is the case in the shown embodiment, to the supporting ring J5 can be fixed a guiding 1 2^ having seated thereon a torsion spring _1_1_ whose free end leans against the inner face of the moving ring J^ and which serves to create additional pressure of the moving ring _1_ on the stationary packing ring 1_ . The torsion spring \ \_ provides for the pressure on the moving ring 1_ when the drum filter is being set into operation, when the drum 5_^ is being fed with liquid and the moving ring 1_ is not yet pressed onto the stationary packing ring 2_ by the hydrostatic pres¬ sure, because the level of the liquid in the drum 5_ has not yet reached the resilient ring membrane .

In another, not shown embodiment, the stationary packing ring 2_ can be mounted (seated) on the face 7_ of the drum 5_, and the moving ring _1_ together with the other related parts of the sliding ring packing can be seated on the stationary frame 3^.

In the drum filter operation, soiled liquid is in a well-known manner fed into the drum J5 in the direction of the arrow through the hole provided in the stationary frame J3 through the sliding ring packing and is due to the hydrostatic pressure resulting from the level difference inside and outside the drum 5_ in a well-known way filtered through the filter cloths of the drum 5_. Said hydrostatic pressure acts on the resilient ring membrane k_ and through its free part between the moving ring _1_ and the place of gripping between the stop j_;_0 of the supporting ring 6_ and the guiding ring _8 exerts pressure force on the moving ring _1_. Thus, the resilient ring membrane _4 acts at the same time as a packing member of the inner space of the drum 5_ and as a driving member of the moving ring ]_.

Non-uniform deposition of soiled matter on the cloths of the drum 5_ can result during the drum rotary movement in impacts leading to radial or axial swings of the drum J5. Radial swing of the drum 5_ results in a reversing radial displacement of the moving ring 1_ on the stationary packing ring 2_. Axial swing of the drum 5_ results in axial swing of the supporting ring j) fixed to the drum 5_. The motion of the support¬ ing ring β_ is shared by the resilient packing member 9_ , guiding ring 8_^, and by the part of the resilient ring membrane 4^ gripped between the guiding ring 8_ and the stop _10 °f ^tne supporting ring 6_ . In each of these cases, the guiding ring 8_ remains pressed to the stationary packing ring 2_^ due to the hydrostatic pressure on the resilient ring membrane 4_.

Field of Application

The sliding ring packing according to the invention can be used for the packing of the inlet parts of the drum filters of waste water or for the packing of other large-diameter slowly or interruptedly rotating parts.

Claims

PATENT CLAIMS

1. A sliding ring packing between two parts, in particular a packing on the inlet part of a drum filter comprising a stationary packing ring fixed to one of the parts and, pressed onto it, a moving ring coupled with the other of the two parts, characterized by that to the moving ring (1) there is fixed one end of a resilient ring membrane (4) whose the other end is fixed between a guiding ring (8) and a supporting ring (6) between which is seated an overlapping resilient packing providing for the pressure of the guiding ring (8) on the supporting ring (6).

2.A sliding ring packing as claimed in Claim 1, characterized by that the other end of the resilient ring membrane (4) is put on the guiding ring (8) by means of which the resilient ring membrane (4) is fixed to the supporting ring (6), said end of the resilient ring membrane (4) being pressed by the resi¬ lient packing member (9) to the guiding ring (8).

3. A sliding ring packing as claimed in Claim

1, characterized by that on the supporting ring (6) there is seated a torsion spring (11) whose free end leans against the guiding ring (8).