SU761720A1 - Cooling-turbine shaft combined sealing assembly - Google Patents

Description

The invention relates to refrigeration, in particular to the turbo-refrigerators of the air conditioning system.

Known combined sealing units containing an external contact mechanical seal enclosed in a housing with a central hole for the shaft, and screw-sealing the seal [1].

A disadvantage of the known structures is that the contactless screw-seam sealing in combination with the external contact mechanical seal is ineffective and worsens the working conditions of the latter, creating an increased pressure drop on the sealing contact pair, reducing the reliability and tightness of the sealing assembly.

The purpose of the invention is to improve the operational reliability and tightness of the sealing unit.

This goal is achieved by the fact that the sealing unit additionally contains a sleeve mounted on the shaft in the area of the screw-and-seals seal, on which a contactless labyrinth seal with parallel annular grooves is made, and the groove of the screw-sealing cup is made on the edges of the end grooves of the contactless labyrinth pack 2

and has the opposite direction to the shaft rotation.

In addition, the groove of the screw sealing is additionally made on the surface of the housing 5 in the zone of the central opening and has a direction opposite to the direction of the groove made on the ribs; the grooves of the screw-sealing seals are made multiple; Yu annular grooves on the sleeve are made with a rough surface; the end part of the sleeve from the side of the sealed medium is made with a conical widening; A sleeve made of antifriction material, mainly a composition of polyimide with graphite or disulfide, is fixed in the central opening of the housing;

molybdenum.

FIG. Figure 1 shows schematically the described sealing assembly; in fig. 2— face seal with a helical groove on the surface of the central hole; in fig. 3 - labyrinth seal sleeve with screw grooves made on its 25 ribs; in fig. 4 - sealing

knot with anti-friction. sleeve.

The sealing unit contains an external mechanical seal consisting of a spring-loaded sleeve 1 and a rotating sleeve up to 2, enclosed in a housing 3 with a central

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761720

hole 4 for the shaft 5. On the surface of the hole 4 are made grooves 6 screw-sealing. A shaft 7 is installed on the shaft 5, on which a contactless labyrinth seal is made with parallel annular grooves 8. On the fins 9 of the grooves 8, a groove 10 of the screw-top sealing can be made. The helical grooves 10 have a direction opposite to the direction of rotation of the shaft 5, and the grooves 6 are opposite to the direction of the grooves 10. The helical grooves 6 and 10 can be made multiple-threaded. The annular grooves 8 are made with a rough surface. The end part of the sleeve 7 from the side of the medium to be sealed is made with a conical widening 11. In the central hole 4 a sleeve 12 of antifriction material can be installed. The sleeve 2 is adjacent to the impeller 13, and the sleeve 7 - to the oil-reflecting washer 14. The static sealing element of the mechanical seal can be made in the form of an elastic, for example rubber, ring 15. Between the screw-sealing and mechanical seals there is a cavity 16.

The described sealing assembly operates as follows.

The main sealing element in the operating mode of the turbo-cooler is a labyrinth seal with annular grooves 8. During the periods of starting and stopping the turbo-cooler, the shaft rotation speed is insufficient for efficient operation of non-contact seals. During these periods, as well as with a non-rotating shaft 5, the hermetic stability of the turbo-cooler is ensured by a torzetm seal of the sleeves 1-2. In a non-working turbo-cooler, oil may enter the cavity

16. Evacuating the oil back into the cavity with the medium to be sealed is carried out with the help of helical grooves 6 and 10 in the initial period of acceleration when the turbo cooler starts, when the shaft rotational speed is still low. Under these conditions, the labyrinth seal with annular grooves 8 works with reduced efficiency and does not prevent the movement of oil along the helical grooves.

The surface roughness of the ring grooves, due to increased friction with adjacent air layers, contributes to ’increase in the intensity of ring vortices locking the working gap between the rotating sleeve 7 and the housing 3. Conical broadening 11 contributes to more intensive discharge of oil from the rotating sleeve 7 to the Starting moment of the turbo-hollower.

The sleeve 12 of antifriction material, built into housing 3, improves the reliability of the seal in terms of vibration, preventing jamming of rotating and non-rotating seal parts when they are in contact.

The economic effect from the use of this invention is to increase the operational reliability and efficiency of the turbo-cooler.

Claims (7)

Claim 15 1. Combined sealing unit a turbo-cooler shaft, containing an external contact mechanical seal enclosed in a housing with a central hole for the shaft, and screw-sealing, characterized in that, in order to increase operational reliability and tightness by suction of oil from the contact mechanical seal, the assembly further comprises a sleeve, 25 mounted on a shaft in the zone of an early-sealing seal, on which a non-contact labyrinth seal with parallel grooves is made. 2. The node in π. 1, characterized in that 30 that the groove of the screw sealing is made on the edges of the annular grooves of the contactless labyrinth seal and has a direction opposite to the direction of rotation of the shaft. 35 3. The node under item 2, characterized in that that the groove of the screw sealing is additionally made on the surface of the body in the zone of the central hole and has a direction opposite to the direction of the groove made on the ribs. 4. Node on PP. 1-3, characterized in that the grooves screw-cutting sealing made multiple. 5. Node on PP. 1-4, characterized in that the annular grooves on the sleeve are made with a rough surface. 6. Knot on PP. 1-5, characterized in that the end part of the sleeve from the side of the sealed medium is made with a conical widening. 7. Knot on π. 1, characterized in that a sleeve made of antifriction material, preferably a polyimide composition with graphite or molybdenum disulfide, is fixedly mounted in the central opening of the housing.