SU832197A1 - Shaft vacuum seal - Google Patents

Description

I

The invention relates to vacuum technology and, in particular, can be used in installations for physical physics research, vacuum metallurgy and other ultra-high vacuum installations that require rotational-oscillatory movement of objects under ultrahigh vacuum conditions.

Vacuum seals are known on the spherical surface in the form of rubber cuffs 1.

However, they cannot be used in ultra-high-voltage installations due to low temperature resistance and high gas-neutral temperature.

Closest to the proposed invention is a vacuum shaft seal, which contains a bath with an inner wall and a liquid seal mounted on the housing, as well as a separating cup and a pre-dilution chamber 2 tightly connected to the shaft.

However, the known seal does not seal against oscillatory movements of the shaft.

The purpose of the invention is to provide a sealed shaft for rotational oscillation.

The goal is achieved by the fact that, in a known seal, the inner wall of the bath is made in the form of a spherical shell fixed on the base of the bath, the latter is connected to the shaft with a ball joint, the preliminary dilution chamber is formed by the base of the bath and the elastic membrane placed between the housing and shaft, iron this separating cup is designed as a no.iy sphere.

In addition, the spherical joint is formed by an insert with an external spherical surface connected with a separating cup by a thin-walled tube. The membrane is connected to the shaft with a lip seal and made reinforced.

The drawing shows a high vacuum shaft seal.

Claims (2)

The seal P1e contains a bath 2 installed on the housing with a liquid hardener 3. A low-melting Mora.iui is used as a sealant (oto, INDIA or iix eutectic cii / iaB. Ll the sealant 2 reduces the number of sealant with a spherical shell 4. On the shaft 5 hermetically sealed separating cup 6, made in the form of a hemisphere, h spherical ball 7, mounted in a conical recess a, made in the wall of bath 2. The cylindrical part b of the ball joint 7, which is a thin-walled tube, is used as heat bridge to reduce heat flow to the shaft 5. The ball joint 7 is secured using elastic elements 8 and a tapered sleeve 9 having a spherical recess B. To improve the sealing working conditions and increase its reliability, grooves are made on the surface a and b balls 10. In the lower part, the shaft 5 is sealed by a forevacuum seal 11 with a bearing 12. The seal 11 is hermetically connected to the housing 1 by an elastic reinforced membrane 13, which is the bottom wall of the pre-discharge chamber stress. A heater 14 is used to obtain the liquid phase of the seal 3. The fixing of the bath 2 to the working volume of the high-vacuum unit (not shown) is carried out with the help of the flange 15. The seal works as follows. Before using the seal in the bath 2, the molten seal 3 is poured into the bath. In order to ensure the tightness of the wall, the bath 2 and the separator cup 6 must be coated or coated with methane, 1 liter, well-wetted sealant. Then the connecting flange 15 is hermetically sealed to the working volume of the installation (not shown) and the working chamber of the installation and the pre-dilution seal are pumped out. After this the seal is READY to work. In order to transmit the desired type of movement, either the compaction shaft 5 is inserted or pumped. A simultaneous vibrational-oscillatory movement of the shaft 5 is possible. During oscillatory movement of the shaft, the separator cup 6 enters the bath 2, bounded on one side by the cylindrical wall, on the other by the spherical shell 4. At the same time, the ball joint 7 rotates and oscillates but the balls 10. during the continuous pumping out of the internal cavity of the seal with the aid of a forevacuum pump (not shown in the drawing). The membrane 13 provides the possibility of oscillating movement of the shaft 5. The proposed seal can be used in installations with pressures up to 5-10 mm Hg. Art. and below. The seal has a high tightness, characterized by total leakage. lower limit of the maximum sensitivity of modern mass spectrometric means of leak detection. In addition, the seal has a small amount of gassing (10 ° L-m. Mer) and leakage (5 10 2 l-mm Hg. Art./s), high reliability, the ability to transfer high torque, long service life ( 10,000 hours), the possibility of oscillatory movement of the shaft in the working volume of the chamber and the absolute accuracy of the transmitted movements due to the rigid connection. Claim 1. Vacuum shaft seal, a tub with an inner wall and a liquid seal installed on the body, as well as a separating cup and a pre-dilution chamber sealed to the shaft, characterized in that, in order to seal the shaft, it is vracially oscillatory motion, the inner wall of the bath is made in the form of a spherical shell fixed on the base of the bath, the latter is connected to the shaft with the aid of a ball joint, a preliminary dilution chamber osnovanie.m bath would be formed and the elastic membrane raz.meshennoy between the housing and the shaft, wherein the glass spacer is designed as a hemisphere. 2. A seal according to claim 1, characterized in that the ball joint is formed by an insert with an external ball surface connected with a separating cup by a thin-walled tube. 3. Seal on PP. 1 and 2, characterized in that the membrane is connected to the shaft with a lip seal. 4. Sealing on PP. 1--3, characterized in that the membrane is made reinforced. Sources of information taken into account in the examination 1. B. Danilin. Fundamentals of designing vacuum systems. M., “Energie, 1971, p. 222-225. 2. USSR author's certificate number 177715, cl. F 15 T 15/52, 1963 (prototype). Pumping out