SU1576755A1 - Labyrinth packing - Google Patents

Abstract

The invention relates to a sealing technique and can be used as a non-contact seal for rotating shafts. The purpose of the invention is to reduce the leakage of the medium through the seal by providing a guaranteed gap between the scallops and the shaft. The seal contains a strip 2 with scallops 3 installed in the housing, the top of each of which has a protrusion 4 from the side of the low-pressure cavity A and a protrusion 5 from the side of the high-pressure cavity B. Between the protrusions 4 and 5 there are jumpers 7 located along the axis of the shaft 6. The scallops 3 are designed so that the projection of point 0, dividing the comb base in half, on a plane parallel to the axis of the shaft 6, lies closer to cavity A than the projection on this the plane of the point K, which lies at the top of the protrusion 5. 2 Il.

Description

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The invention relates to a sealing technique and can be used as a non-contact sealing of rotating shafts.

The purpose of the invention is to reduce the leakage of the medium through the seal by providing a guaranteed gap between the scallops and the shaft.

Figure 1 shows the seal, a longitudinal section; in FIG. 2, node I in FIG.

The seal contains a strip 2 with scallops 3 installed in the housing 1, the top of each of which has a protrusion 4 located on the side of the low-pressure cavity A, and a protrusion 5 located on the side of the high-pressure cavity B, covering the shaft 6. Between the protrusions of the tops of each comb are made lintels 7 located along the shaft axis b. The scallops 3 are made in such a way that the projection of point 0, which halves the base of the scallop 3 in half, on a plane parallel to the axis of the shaft b, lies closer to cavity A than projects to this plane of point K lying on top of a protrusion 5 located on the side of the cavity B.

Seal works as follows.

Distance H between the top of the protrusion

5 and point 0, which divides the base of the scallop 3 in half, is selected from the ratio

R — 0.05 mm H R — 0.02 mm where R is the distance between point 0 and shaft 6.

The seal is mounted on the shaft 6 with tension. With this, the protrusions 4 are in contact with the shaft 6, the protrusions 5 are protected from damage during assembly. At the beginning of the start-up, the scallops 3 are folded back towards a greater pressure of 0.03 mm, which is ensured by their ductility. Protrusion

6 the comb 3 is located closer to the shaft 6 than the protrusion 5. In this case, when the unit is stopped and started, the protrusion 5 is protected from abrasion.

With a radial runout of the shaft 6, an uneven gap is created with the protrusion 4 of the scallop 3. In an area with a smaller gap, an excessive pressure is created. To keep it in a zone with a small gap and to avoid leaks in the radial direction between two adjacent scallops 3 to the zone with a large radial gap between

shaft 6 and the protrusion 4 of the scallop 3, between the latter are located jumpers 7.

Thus, the overpressure increases the pressure drop on the scallop 3 in the zone of a small gap with the shaft b and bends

the comb 3 in the direction of the cavity of lesser pressure, ensuring a constant clearance. In the zone with a large gap between the scallops 3 and the shaft b, a decrease in the pressure differential causes a decrease in the gap, so

as a zone of reduced pressure is created which reduces the pressure drop on the scallop 3. This is caused by the elasticity of the scallops 3, which are pre-deformed during the assembly of the seal.

Using the proposed seal design in the gas pumping unit will reduce the amount of gas leakage and increase the reliability of the unit as a whole.

Claims (1)

The invention of the labyrinth seal, made in the form of separating cavities of high and low pressures of the shaft of inclined scallops with a backlash, which are successively installed in the housing, with obliquity scallops with vertices consisting of two protrusions of different lengths, in order to reduce medium leaks through the seal by providing a guaranteed gap between the scallops and the shaft, the protrusion of the apex of each scallop, located on the side of the low pressure cavity, is made with a smaller gap relative to shaft with a protrusion located on the side of the high pressure cavity, whereby the projection of the point dividing the base of the scallop is. floors on a plane parallel to the axis of the shaft lies closer to the low pressure cavity, than the projection of the point lying on top of the protrusion located on the side of the high-pressure cavity, with bridges between the protrusions of the tops of the scallops directed along the axis of the shaft. 0 FIG. one