SU1635029A1 - Stand for impact tests of products at cryogenic temperatures - Google Patents

Abstract

This invention relates to a testing technique. The purpose of the invention is to increase efficiency by reducing the heat input to the test product through a waveguide that provides the transfer of shock load — achieved by using vapors of a cryogenic liquid that cools the test product for subsequent cooling of the waveguide. The stand contains a cryostat 1, a working chamber 3 connected to the source 4 of liquid helium by means of a nozzle 5 hermetically inserted into the chamber 3, a table 8 for mounting the product 9, a shock load causative agent 10 and a rod-waveguide placed in the guide sleeve 11 12 and textolite 13 rods. The sleeve 11 has on its inner surface a helical groove 15 for vapor removal, liquid helium along the rod 13 into the gas tank 16. When the product 9 is cooled with helium supplied from the nozzle 5, the helium vapor enters the helical groove 15 and, along the rod 13, removes heat flow through it to product 9. This reduces the consumption of helium and accelerates the testing process. 1 il. I Yu

Description

The invention relates to testing equipment, in particular to stands for testing products for impact at cryogenic temperatures.

The purpose of the invention is to increase the cost-effectiveness of tests by reducing the heat influx to the test product by using vapors of a cryogenic liquid cooling the test product for the subsequent cooling of the waveguide rod, which transfers the dynamic load from the load exciter to the test product. fifteen

The drawing shows the proposed stand for testing products for impact at cryogenic temperatures.

The stand contains a cryostat 1 with a vacuum jacket 2, a working chamber 3 located in it 20, connected to a liquid helium source 4 by means of a nozzle 5, a pipe 6 and a valve 7, which is hermetically inserted into the chamber 3, and a table 8 is placed in the chamber 3 for 25 installation of the test product 9 , shock exciter 10 and a waveguide rod located in the guide sleeve 11, consisting of a steel rod 12 coaxially mounted and in acoustic contact, interacting with the exciter 10, and thermal rod 13 in contact with the table 8 ’elastic material (for example, tech-stolite). The working chamber 3 is hermetically connected to the sleeve 11 by means of screws 14. The sleeve 11 is made with a helical groove 15 on the inner surface, which serves to divert liquid helium vapor from the chamber 3 along the waveguide rod to the gas holder 16, which serves to discharge helium gas. The sleeve 11 is made of a heat-insulating material and mounted on the exciter housing 10. From the second of the chamber 3, there is a gap 17 between the sleeve 11 and the rod 13 for supplying helium to the groove 15. The nozzle 5 is inserted into the cryostat 1 through the heat-insulating gasket 18, and into the chamber 3 50 through an airtight gasket 19. The cryostat 1 is attached to the lower flange of the sleeve 11 through the heat-insulating gasket 20. The outer surface of the sleeve 11 is covered by a cooling 55 spiral pipe 21 connected to a liquid nitrogen source 22. The cavity of the cryostat 1 is filled with a heat insulating medium 23. A dense acoustic contact ’of the rods 12 and 13 is ensured by means of rubber rings 24 о. Vacuumization of the jacket 2 is carried out using a vacuum pump 25.

The proposed stand for testing products for impact at cryogenic temperatures is as follows.

To install the test product 9, remove the cryostat 1 and the working chamber 3. After installing the product on the table 8, collect the cryostat 1 and vacuum the jacket 2. Cool the cryostat 1 by passing liquid nitrogen through a spiral pipe 21. Opening valve 7, liquid helium is fed through nozzle 5 into working chamber 3. The product 9 is cooled by liquid helium vapor, which is formed when the nozzle 5 exits the nozzle. Due to the fact that liquid helium is fed through the nozzle 5 under pressure, the vapor of liquid helium is pushed through the annular gap 17 and then along helical groove 15, cooling the waveguide rod. Then the bunks of liquid helium are collected in the gas tank 16 for their subsequent regeneration. The helical groove 15 of the guide sleeve 11 provides a large path for the interaction of liquid helium vapor with the surface of the rod 3, creating optimal heat transfer conditions, which reduces the heat flux going through the rod 13 to the test product 9.

Upon reaching the required temperature in the cavity of the chamber 3, the shock exciter 10 strikes the lower end of the rod 12. The resulting compression wave is transmitted through the rod 13 and table 8 to the test product. to 9.

The cryostat 1 and chamber 3 do not experience impact during the tests, since they are mechanically isolated from the shock exciter through a fixed guide sleeve 11.

The use of liquid helium vapor cooling the test article 9 to remove the heat flow going to the foot 8 along the rod 13 allows to reduce the flow of liquid helium and accelerate the achievement of the required cooling temperature, which improves the efficiency of the tests.

Claims (1)

Claim A stand for testing products for impact at cryogenic temperatures, comprising a cryostat with a working chamber, connected to a source of cryogenic liquid, a table placed in the working chamber, used to fix the test product, an impact exciter mounted outside the cryostat, and a water wave rod placed in the guide sleeve, serving to transfer a dynamic load from the pathogen to the table, characterized in that, in order to increase the efficiency of the tests by reducing the heat flow to the tested product, the working the chamber is hermetically connected to the guide sleeve, and the sleeve is made with a helical groove on the inner surface, which serves to divert the vapor of the cryogenic liquid.