CS206509B1 - Steady packing with sliding ring,especially for medium with delaterious effects - Google Patents

Abstract

Gland seal which is axially slidable includes a primary axially slidable sealing ring abutting a rotary sealing collar, the sealing ring being guided for axial displacement and rotary constraint in a sleeve which is fast with a cap. Sleeve encloses a compression mandrel one end of which presses a sec. sealing ring made of PTFE against the adjacent face of the sealing ring, whilst the other end is pressed in the direction of the sealing ring by a packet of torsional springs. Sealing ring is permitted limited axial displacement in a setting ring which is enclosed by the cap attached to the housing. Used in acid pumps having metallic or plastics parts. Seal is arranged about pump impeller shaft adjacent the impeller. Seal provides adequate protection against aggressive agents and improves service reliability of pumps. Seal permits of relief of pressure on secondary sealing ring, adjustment of wear.

Description

BACKGROUND OF THE INVENTION The present invention relates to a stationary slide ring seal for sealing environmental media and substances on rotating shafts of an aggregate, particularly for aggressive environments in acid pumps.

It is known that seals are installed at shaft or axle passageways to prevent leakage of environment from the inside of the unit · In recent years, the use of sliding ring seals has been increasingly used ·

The peculiar eaten, ^and of vznikaaí ^p ut s ^{n of} the IP ^and the power unit ^P in the chemical rslu r ^um, especially ^E on pumps which dopaazují highly corrosive environments and 'therefore are made of a camper maaeeiálu resistant to corrosion. For these applications, gaskets with a sliding ring of pol-ytetrafluoroethylene and its compounds are known, the basic design of which consists of a cylindrical bellows or bellows.

In these known sliding ring seals, the suspension is carried out both by means of a single spring and group cushioning. The sliding surfaces are connected to the bellows by sintering or are fixed in a different way and are countercirculated via the suspension.

Furthermore, stationary seals with a sliding ring are known, which as a component are inserted into the sealing space and whose sliding ring is cut into the rotating counter-ring.

In the case of metal seals with a sliding ring, it is known to use rings of different profiles, such as round, kilos, etc., of various plastics, preferably polymers, for sealing axial leak paths.

These sliding ring seals have disadvantages which are mainly based on the physical properties of the material, in particular polytetrafluoroethylene, i.e. the compressive loadability of cylindrical bellows or bellows at given diameter and wall thickness ratios is low and leads to unacceptable deformations of bellows folds at higher temperatures. short-term failure of the slide ring seal.

Stationary sliding ring seals require high manufacturing accuracy and low axial tolerance of the unit to be sealed, since the possible installation length is limited and no additional adjustment is possible from the outside when the unit is assembled.

The compression springs used are made of stainless steels and acid-resistant steels and, moreover, are directly or indirectly more or less effectively protected against the harmful effects of the sealed environment, both of which are large in size and tear due to the constantly oscillating loading of small cylindrical springs. they flatten the coatings, making the springs ineffective, especially when directly exposed to aggressive environments.

Used secondary sealing members of polytetrafluoroethylene are subject to cold creep when subjected to constant pressure loads.

Since the time between pump installation and commissioning, especially in new investments, may be greater than the average operating time of the slide ring seal, the absence of unloading potential may already render the secondary seal members inoperable.

The purpose of the invention is to provide a sliding ring seal which, despite simple construction, guarantees a perfect sealing of the spaces, especially in acid pumps, provides optimum protection against aggressive environments and substances, increases the functional reliability and durability of the seal, and finally guarantees replaceability of functional elements and easy maintenance.

SUMMARY OF THE INVENTION The present invention is based on the task of providing, for aggressive environments in pumps, particularly acid pumps, a seal which, independently of the operating temperature, manages high operating pressure and has optimum corrosion resistance to the pump materials. the pump mounted state allows the wear path to be adjusted as well as the relief of the built-in secondary sealing members even when the pump is mounted.

According to the invention, the sliding ring group suspension is provided with a corrosion-resistant, adjustable, pressure-resistant and contamination-resistant spring cassette consisting of a thrust sleeve surrounding a partially sliding ring and a shaft sleeve and overlapped with axial clearance by the guide sleeve towards the sliding ring. using a stopper, abutting against the wedge ring at one end and slidingly covered by a spring support at the other end, and a corrosion-resistant suspension is placed between the thrust sleeve and the spring support, the spring support being located in and attached to the guide sleeve and an adjusting ring is provided, which is axially settable for pressure relief of the wedge ring and, together with the guide sleeve, is fastened to the pump housing by means of a sleeve flange over the cover.

The suspension consists of rotary springs which are wrapped with a polytetrafluoroethylene hose and are capped at the ends, whereby the sealing point between the hose and the cap is permanently under axial pressure and is thus additionally loaded for sealing in force contact.

All parts which come into contact directly or indirectly with the sealed environment consist of alumina, industrial carbon and plastics, in particular polytetrafluoroethylene and its compounds.

The sealing of the sealing chamber, which is under pressure, occurs by the relative movement of the slide ring and the counter ring. The counter ring rotates and is axially fixed by the impeller collar with the shaft sleeve and is flat with respect to the shaft! seals. The wedge ring, which is under elastic tension, seals the gap between the slide ring and the guide sleeve. The sliding ring and the elastic support are secured against turning by pins. Additional adjustment of the sliding ring for wear is ensured by the rear sealing of the spring cushioning of the spring cassette. The thrust of the sliding ring against the counter ring is exerted by the group suspension and, when there is an internal pressure, is generated mainly by this pressure.

The stationary seal is sealed externally with a circular ring which is mounted in the pressure ring and fixed by the adjusting ring. In order to complicate the manufacturing tolerances of the pumps of the unit, but also to re-adjust after re-use, the prescribed slide ring bias is achieved by turning the adjusting ring and thereby achieving the displacement.

The invention will now be described by way of example with reference to the drawing.

Giant. 1 shows a longitudinal section through a pump housing using a sliding ring seal.

Giant. 2 · is a view of a rotating spring.

The slide ring seal shown in FIG. 1 is located in the sealing space 1 which is formed in the pump housing 2. With the outer diameter of the guide sleeve 4, the slide ring seal in the headspace sealing chamber 14 and the lid 24 are pressed against the pump housing 2 and locked by a professional ring via the compression ring 14 secured against rotation by the pin 16 in the longitudinal groove 21 and the adjusting ring 15. 19 Dec

The sliding ring 8 is guided axially slidingly in the parent sleeve 2 and is secured against rotation by the pin 16 in the longitudinal groove 19. The straight profile ring 10, designed as a slip ring, causes a secondary sealing of the environment in the sealing space.

The rotating counter-ring is held on the shaft 3 between the shaft sleeve 4 and the impeller collar 2 and is sealed on both sides to the shaft 2 by gaskets. A closed spring cassette -22 is provided to press the stationary slide ring 8 onto the rotating counter-ring. The closed spring cassette 22 consists of a thrust sleeve 11 which is axially displaceable in the guide sleeve 4 and at the same time secured against rotation of the pin 16 in the longitudinal groove 20, and a spring support 12 which is slidable over the thrust sleeve 11 and Pinned by pins 17.

By means of the compression sleeve 11 and the spring support 12, the spring cassettes 22 in opposed bores 28 are fitted with rotating springs 11j with their ends which are closed by caps 25 and are fixed permanently behind the bias in their position. The closure of the spring cassette and the use of the rotary springs thus protected prevent the destruction of the suspension even if the gaseous product is leaking or leaking. when there are small leaks. Through the adjusting ring 15 and the thrust ring 14, an axial adjustment of the sliding ring 8 with respect to the counter ring 8 is carried out by means of a thread 20 on the guide bushing 8, thereby simultaneously adjusting the load of the rotary springs 13 and thus the load of the secondary seal.

According to FIG. 2, the complete rotary spring 11 consists of a spring 26 which is coated with a hose 27, preferably of polytetrafluoroethylene, and whose ends are tightly closed by caps 25.

The slide ring seal is preferably used as a seal in metal and non-metallic pumps that convey aggressive environments and substances. Accordingly, the main advantage of a stationary slide ring seal is that the functional members are corrosion resistant and protected against contamination for optimum sealing, thereby ensuring greater operational reliability and safety of the slide ring seal. Further advantages result from the inventive connection of the spring cassette and the adjusting ring, whereby the pumps can be mounted with pressure-relieving secondary seals until they are introduced into the vehicle. Due to the sealing of the stationary seal with the outer ring inwards, optimum tightness is achieved. The prestressing necessary for the seal can be adjusted from the outside via the stationary slide ring seal when the pump is installed. Dimensional differences due to manufacturing tolerances can be overtightened in standardized sealing spaces without any additional work, thus greatly. simplifies assembly of the entire pump.

Moonoot makes it easy to replace sliding rings and PM-rings without altering the design of the seals by using materials that are favorable to the operating parameters.

Claims (4)

Stationary seals with slip ring, especially for aggressive environments in acid pumps with slip ring, which bears on the counter-ring fixed between the impeller and the shaft sleeve, is axially loadable and displaceable via the group suspension and is radially secured against a guide bushing lockable in the pump housing, wherein the slide ring is sealed by a secondary sealing member, such as a wedge ring of polytetrafluorooretly ^, to the guide bushing, characterized in that the group suspension of the slide ring (8) is formed by a spring cassette (22) resistant corrosion which is pressure-adjustable and sealed against contamination and consists of a thrust sleeve (11) which partially surrounds the slide ring (8) and the shaft sleeve (4) and is covered with axial clearance by a guide bushing (9) provided with a slide ring and tops at one end on the wedge ring (10) and on the other end slidingly covered by a spring support (12) and a compression sleeve (11) is provided by the compression sleeve (11) and the spring support (12), the spring support (12) being provided an axially adjustable adjusting ring (15) is provided in the guide sleeve (9) and connected thereto and on the guide sleeve (9) for pressure relief of the wedge ring (10), which is flange mountable on the pump housing (2) via the cover (24), which surrounds it together with the guide sleeve (9). 2. The sliding ring seal according to claim 1, characterized in that the suspension consists of coated rotary springs (26). 3. The sliding ring gasket according to claim 2, characterized in that the rotation springs (26) are wrapped with a polytetrafluoroethylene hose (27) sealed at the end with caps (25), the rotating springs (26) being mounted so that wherein the sealing point between the hose (27) and the cap (25) is permanently below the axial thallium. * 4. A stationary slide seal according to Claims 1 to 3, characterized in that all parts which come into contact directly or indirectly with the sealing medium consist of technical ceramics, technical carbon with suitable impregnations and plastics, preferably polytetrafuoretlylene and of its compounds.