RU2531482C1 - Magnetic fluid shaft seal ps36 - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: magnetic fluid seal of the shaft containing magnetic system, composed from ring-type constant magnets, facing to each other with the same poles, and polar attachments, the surfaces of which one are made aflush with the magnet surfaces lapping the shaft and forming with the shaft a clearance filled with the magnetic fluid. On surfaces of polar attachments facing to the shaft, and shaft opposite to magnets the grooves are made. The magnetic system is made as the uniform block and is fixed motionlessly through the face surface on the intermediate disk. The seal is additionally equipped with a sleeve, placed on the shaft, laps the magnetic system outside and forms with it a clearance filled with the magnetic fluid. On the surfaces of polar attachments facing to the sleeve, and on the sleeve surface against magnets the circular grooves are made.

EFFECT: improved retention capacity of magnetic fluid seals.

1 dwg

Description

The invention relates to a sealing technique and can be used to seal magnetic and non-magnetic shafts operating under differential pressure conditions.

A magneto-liquid seal is known (USSR Author's Certificate No. 1283476, IPC F16J 15/40, 1985), containing an annular permanent magnet, pole attachments with conical protrusions, stacked washers with non-magnetic gaskets between them, while the protrusions of adjacent washers adjoin the conical protrusions of opposite consoles polarity.

The disadvantages of this magneto-liquid seal are the design complexity and the insufficiently low held pressure drop. The latter drawback is due to the high scattering fluxes of the magnetic system.

Known magneto-liquid seal (USSR Author's Certificate No. 1308803, IPC F16J 15/40, 1987), adopted as a prototype, in which the magnetic system consists of permanent magnets facing each other with the same poles and separated by pole attachments, the surface of the latter facing the shaft, made flush with the surfaces of the magnets, while ring grooves are made on the surfaces of the pole attachments and the shaft opposite the magnets.

The disadvantages of this magneto-liquid seal are insufficient holding capacity and large dimensions.

The technical result achieved by the invention is to increase the holding capacity of the magneto-liquid seals.

The technical result is achieved in that a magnetically liquid shaft seal containing a magnetic system consisting of ring permanent magnets and pole attachments facing each other by the same poles, the surfaces of which are flush with the surfaces of the magnets, covering the shaft and forming a gap filled with magnetic fluid with the shaft, at this, on the surfaces of the pole attachments facing the shaft and the shaft opposite the magnets, grooves are made, the magnetic system is made in the form of a single unit, fixed Clearly through the end surface on the intermediate disk, the seal is additionally equipped with a sleeve that is placed on the shaft, covers the magnetic system from the outside and forms a gap with it filled with magnetic fluid, while on the surfaces of the pole attachments facing the sleeve and on the surface of the sleeve opposite the magnets are made annular grooves.

Figure 1 shows the proposed magneto-liquid shaft seal.

The magneto-liquid seal consists of a magnetic system containing annular permanent magnets 1, which face each other with the same poles, and between which annular pole attachments 2 are mounted. The outer and inner surfaces of the pole attachments are flush with the surfaces of the magnets. The magnetic system covers the shaft 3 and forms a gap 4 with the shaft. The magnetic system is made in the form of a single block and is fixed motionless through the end surface on the disk 5, equipped with an opening for mounting on the shaft. Magneto-liquid seal through the disk 5 is attached to the housing of the sealed device. A sleeve 6 is fixed on the shaft 3, which covers the magnetic system, forming a gap 7. Magnetic fluid 8 is introduced into the gaps 4 and 7. On the surfaces of the pole attachments 2 facing the gap 4, annular grooves 9 are made, on the surfaces of the pole extensions 2 facing the gap 7, made of annular grooves 10. On the shaft 3 opposite the permanent magnets made grooves 11, on the sleeve 6 opposite the permanent magnets made grooves 12.

Sealing works as follows. Permanent magnets 1 in the seal serve as a source of magnetic field. The magnetic flux generated by two adjacent magnets is divided into two parts. One part of the pole prefixes 2 is brought to the gap 4 between the pole prefixes 2 and the shaft 3, passes through the gap 4, is divided into two parts, closes to adjacent pole consoles adjacent to the opposite poles of the magnets. The second part of the magnetic flux by the pole prefix is brought to the gap 7 between the pole prefixes 2 and the sleeve 6, passes through the gap 7, is divided into two parts, closes to adjacent pole consoles adjacent to the opposite poles of the magnets. In the gaps 4 and 7 opposite the pole attachments, a high magnetic field is created, where magnetic fluid 8 is drawn in and forms sealed annular plugs with increased internal pressure. Each magneto-liquid plug is capable of perceiving a certain pressure drop, depending on the maximum induction under the pole attachment in the gap. The pressure drop held by the seal is determined by the sum of the drops of all the magneto-liquid plugs in gaps 4 and 7.

The implementation of pole prefixes 2 flush with permanent magnets helps to reduce the surfaces from which the magnetic flux comes out, and to increase the magnetic flux concentration in the gaps, i.e. increase the maximum field strength. The small width of the pole attachments (t≈δ, where t is the thickness of the pole attachment, 8 is the value of the working gap) allows us to achieve high field strengths in the working gaps and, accordingly, a high differential pressure kept by the seal.

The grooves 9 and 10 on the pole attachments when using small working gaps 4 and 7 (2δ <t) create an additional magneto-liquid plug in the gap under each pole attachment, which additionally increases the pressure drop that is kept.

The execution on the surface of the shaft of the grooves 11 and on the surface of the sleeve of the grooves 12, located opposite the permanent magnets, allows you to increase the volume of refueling fluid 8, and therefore, increase the life of the seal between the refills. When sealing magnetic shafts, the grooves reduce the scattering fluxes and, therefore, increase the energy efficiency of permanent magnets. The seal is universal and can be used to seal both magnetic and non-magnetic shafts.

This seal in comparison with the prototype more than doubles the kept differential pressure. This is due to the fact that the sleeve 6 of the shaft 3 allows you to double the number of magneto-liquid seal tubes, using magnetic fluxes, which were previously scattering fluxes.

Thus, the proposed seal can significantly increase the retained differential pressure or for a given differential to reduce the dimensions of the seal.

Claims (1)

A magneto-liquid shaft seal containing a magnetic system consisting of ring permanent magnets and pole attachments facing each other by the same poles, the surfaces of which are flush with the surfaces of the magnets, enclosing the shaft and forming a gap filled with magnetic fluid with the shaft, while on the surfaces of the pole consoles, facing the shaft, and on the surfaces of the shaft, opposite the magnets, grooves are made, characterized in that the magnetic system is made in the form of a single unit and is fixed stationary about through the end surface on the disk, and the seal is additionally equipped with a sleeve that is located on the shaft, covers the magnetic system and forms a gap with it filled with magnetic fluid, while on the surfaces of the pole attachments facing the sleeve, and on the surface of the sleeve opposite the magnets are made ring grooves.