SU892075A1 - Magnetic liquid sealing - Google Patents

Description

(54) MAGNETIC RESISTANCE SEAL

one

The invention relates to a sealing technique and can be applied in all sectors of the industry where sealing of rolls is required when transferring rotation to various chemical, gas and biological environments.

A magnetic liquid seal is known, in which the magnetic system is located directly on the shaft, and the body and the cover are made of ferromagnetic material and with annular grooves on the walls facing the pole attachments. The seal also includes bearings and poles 1.

The disadvantage of the design lies in the fact that under the action of magnetic tension and axial movement of the shaft the gap between the poles changes, and if we consider that the working gap is 0.05-0.15 mm, it is possible that the seal is jammed. In addition, the pressure drop retained on the seal is reduced.

The purpose of the invention is to eliminate the possibility of changing the working gap of the seal when the shaft is axially moved, i.e. increased seal reliability.

This goal is achieved by the fact that the poles, between which there is a spacer sleeve, are mounted on

E poddipniki, located directly on the shaft, and on the surfaces of them facing the body, made annular grooves.

The drawing shows the construction ..j qi seal.

On the non-magnetic shaft 1 there is a magnetic system consisting of an annular permanent magnet 2 with adjacent pole attachments 3, which forms with a ferromagnetic body 4 and poles 5, located on the bearings 6, a closed zone filled with magnetic composition 7. Between the poles 5 installed spacer sleeve 8,

20 provided with annular protrusions, and on the surfaces of the loluses facing the housing / annular grooves are cut to obtain an uneven magnetic field in the gap.

25 Magnet 2, poles, attachments 3, poles 5 and housing 4 form a closed magnetic circuit. In the static mode (the shaft is stationary) the magnetic force resulting from

30, magnetic fluid interaction

rings with a permanent magnet field, prevents the magnetic composition from flowing out under the influence of an external pressure drop. The spacer 8, abutting with its annular ledges on the poles 5, prevents the working gap between the poles 5 and the pole attachments 3.

In the dynamic mode, with the axial movement of the shaft, the entire magnetic system is relocated relative to the housing and the working gap between the poles 5 and the pole attachments remains unchanged. The presence of annular grooves on the surfaces of the poles 5 facing the body increases the gradient of the magnetic field and, with it, the differential pressure held in the gap between the poles 5 and the body 4,

The proposed seal design eliminates the contact between the working parts and, therefore, their wear is practically absent; simple in construction and cheap to manufacture, as it does not require thorough surface treatment; can work for a long time without recharging, since there is practically no leakage of ferrofluid; provides extremely small leaky packs. These advantages make it possible to apply the proposed design in various technical devices: for compacting the shafts of pumps, compressors, turbines, etc. In addition, it can be used to protect against contamination of, for example, biological media.

Claims (1)

1. USSR author's certificate in application number 2729330 / 25-08, cl. F 16 J 15/40, 1979.