Development of a low temperature vacuum test system

In order to satisfy the measurement of physical and mechanical properties of solid and coated materials at low temperatures, a set of cryogenic vacuum testing system has been developed. The device uses solid conduction to cool the heat sink rapidly, simulating the effect of high vacuum and cold black environment on the main performance of the sample. The related technical parameters, such as the cooling rate of heat sink, temperature uniformity and temperature control precision in the equipment are tested and verified, and the result has reached the expected target.

The space environment includes vacuum, electromagnetic radiation, high-energy particle radiation, plasma, micro meteoroid, planetary atmosphere, magnetic field and gravitational field. For aerospace materials, due to the harsh outer space environment, it is necessary to test the aerospace materials. A lot of environmental tests are needed in aerospace technology to detect defects that may occur in products.

At present, the thermal vacuum equipment of TENNEY and BEMCO abroad can adopt the magnetic levitation technology without lubrication and the molecular pump of special speed control motor. The domestic research institute of space technology has developed a lot of thermal vacuum test cases, and the number of manufacturers and products of the specialized thermal vacuum test equipment are numbered, and none of them serialized the equipment like the TENNEY and BEMCO in the United States. In order to meet the needs of the vigorous development of the national space industry, the thermal vacuum test box based on its own development has become a new topic of environmental test equipment.

The cryogenic vacuum testing system is a special experiment and a microcosm of a typical thermal vacuum test equipment. It belongs to customized projects and has a relatively narrow application. In order to test the product at low temperature -180 and vacuum limit of 1 * 10-5 Pa, the system is developed. The final reliability of the product is tested according to the test results.

1. The main technical parameters

The cryogenic vacuum testing system mainly consists of four parts: vacuum vessel, vacuum system, refrigeration system and measurement and control system.

1.1. Vacuum vessel

A, the design size is 600mm x 800mm

B, empty limit vacuum degree: better than 1 x 10-5 Pa;

The total leakage rate of C and vacuum vessel is better than 1 * 10-9 Pa m3/s.

D, the effective size of heat sink: 400mm x 400mm

The surface of E and heat sink is nickel plated and the interior surface is black painted. The emissivity of the inner surface is more than 0.90.

1.2. Vacuum system

A, main vacuum pump adopts Sumitomo cryogenic pump (model: CP-8, limit vacuum 1 * 10-7 Pa).

B, coarse pumping system adopts Japanese dry rock pump (type: ISP-250C, pumping speed 1.5L/s).

1.3. Refrigeration system

When a and heat sink drop from normal temperature to -180 C, the chiller provides cold source (the Japanese Sumitomo model: CH-110).

B, heat sink cooling rate: 0.8 centigrade /min;

1.4. Measurement and control system

A, temperature range: 77K to normal temperature;

B, heat sink temperature uniformity: + 1.5 C;

C, the temperature precision of heat sink: + 0.5 C;

D, heating mode: electric heating.