CN113985950B - High vacuum environment test piece temperature control device - Google Patents

Abstract

A high-vacuum environment test piece temperature control device, which includes a vacuum tank, a sealing flange for sealing the end of the vacuum tank, a heat sink inside the vacuum tank for adjusting and controlling the temperature of the test workpiece, and The pipeline connected with the heat sink and the external temperature control unit. The vacuum tank body is a horizontal cylindrical structure. The heat sink includes a bottom heat sink and an annular heat sink; the bottom heat sink and the annular heat sink form a test cavity for placing a test workpiece. A plurality of sets of heat fins for contacting and conducting heat with the test workpiece are installed on the surface of the heat sink inside the test cavity. The heat fins include an inner heat fin and an outer heat fin whose two ends are overlapped and fixed on the surface of the heat sink; arcuate elastic structure. The invention has the beneficial technical effects of good adaptability and high heat conduction efficiency.

Description

A high vacuum environment test piece temperature control device

technical field

The invention belongs to the field of high-vacuum environment testing equipment, in particular to a high-vacuum environment test piece temperature control device.

Background technique

In recent years, space flight activities such as space stations and satellites in my country have become increasingly complex, the working life of spacecraft has become longer and longer, and the requirements for reliability of space equipment have become higher and higher. When the pressure is lower than 10-7Pa, the moving parts such as switches, relays, connectors and other key electrical and electronic components and components working in a vacuum environment will have a cold welding effect under the action of temperature and high vacuum stress, thus Leading to mechanical and electrical failure of the spacecraft.

When the metal solid is under ultra-high vacuum conditions, the gas adsorbed on its surface escapes. Under the condition that various organic pollution films disappear and the metal oxide layer is broken, the metal surfaces directly contact each other. At this time, the friction between the metals The friction force under relatively atmospheric conditions will increase by more than ten times. At this time, the molecules will diffuse with each other and bond to different degrees. If the surface is clean at the atomic level, further overall adhesion will occur under a certain pressure load, that is, cold welding will occur.

Through years of research at home and abroad, it is generally believed that the main factors affecting adhesion and cold welding are: surface cleanliness, pressure load, contact time, material properties and temperature.

The vacuum degree selected for the high vacuum cold welding ground simulation test is usually between 10-7Pa and 10-9Pa, and the heat sink temperature is -55°C to 90°C. The industry believes that a vacuum with a pressure below 1×10-7Pa is called an ultra-high vacuum. At this time, the number of molecules per unit volume is only 1/1,000,000,000,000 of normal atmospheric pressure.

At present, the latest version of the high vacuum cold welding test method that can be referred to in China is "QJ 20422.5-2016 Aerospace Component Environmental Test Method Part 5: Vacuum Cold Welding Test", which is the aerospace industry standard of the People's Republic of China. Among them, the description of temperature control in Appendix A (reference part) is "Article A5.1.3c) d) The vacuum chamber shall install component heating devices and cooling devices (sometimes replaced by heat sinks). Article 5.1.5 The test temperature control system has The function of temperature control of test components, and corresponding status display. It has alarm prompt, query and storage functions."

The vacuum cold welding test process is summarized as follows:

Before the test, the specimen should be cleaned and treated without oil. Install the sample in the vacuum chamber, seal the vacuum chamber with a metal sealing ring, choose different installation methods according to the shape of the test piece, it can be installed on the fixed base plate or fixed on the corresponding device through the installation flange, and connect the power supply Lines and related test signal lines, after preliminary confirmation that the seal is reliable, start pumping. The vacuum should be at least 1×10-7Pa, and the heat sink of the temperature control device should reach the specified temperature. Keep the corresponding time according to the regulations, and check the performance of the test piece.

Since heat cannot be transferred by convection in a vacuum environment, the main way to control the temperature in a vacuum environment in the existing test methods is through heat sink conduction or radiation, but most of the test pieces have irregular geometric shapes and cannot be adopted by fixtures. The heat sink is conductive, and when the vacuum degree is less than 1×10-7Pa, the molecular density of the environment in the test chamber is extremely low, and the radiation effect not only transfers heat slowly but also makes it difficult to control the temperature of the test workpiece. The test piece cannot reach the specified temperature conditions or the uniformity is poor during the test, so that the assessment purpose of the test cannot be achieved.

Contents of the invention

The purpose of the invention is to solve the problem of low heat conduction efficiency of a test piece during a vacuum cold welding test.

In order to solve the above problems, the present invention proposes a high-vacuum environment test piece temperature control device, which is used to control the temperature of the test piece and improve the uniformity of temperature conduction in a high-vacuum environment (vacuum degree is less than 1×10-7Pa), so as to solve the current problem. There are problems of inaccurate temperature control, poor uniformity and low efficiency in the technology.

The high vacuum environment test piece temperature control device includes a vacuum tank body, a sealing flange for sealing the end of the vacuum tank body, a heat sink inside the vacuum tank body for adjusting and controlling the temperature of the test workpiece, and The pipeline connected with the heat sink and the external temperature control unit.

The external temperature control unit is a heat transfer oil unit, which can control the temperature of the test workpiece from -85°C to 200°C, and the control accuracy can reach plus or minus 0.1°C.

The vacuum tank body is a horizontal cylindrical structure.

The heat sink includes a bottom heat sink and an annular heat sink; the bottom heat sink and the annular heat sink form a test cavity for placing a test workpiece.

The test workpiece is also equipped with a workpiece mounting plate, which is used for testing the conditions of cold welding with the test workpiece under various temperature and vacuum conditions. At the same time, the workpiece mounting plate also has positioning, support and thermal conductivity. When the parts to be tested are matched in groups and the size and shape are suitable for the inner space of the vacuum tube body, there is no need to use the workpiece mounting plate; from the actual needs of testing cold welding, the material of the workpiece mounting plate is required and tested The workpiece is in working condition to match the same material as the part, therefore, the workpiece mounting plate can also be regarded as a component or accessory of the test workpiece.

A plurality of sets of heat fins for contacting and conducting heat with the test workpiece are installed on the surface of the heat sink inside the test chamber.

The heat fins include an inner heat fin and an outer heat fin whose two ends are overlapped and fixed on the surface of the heat sink; arcuate elastic structure.

The hot fins are fabricated from beryllium bronze strips.

The arcuate top ends of the inner heat fins and the outer heat fins are separated by 2-3mm.

The cutting size of the beryllium copper strip is 100mm×10mm×0.2m.

A 6 mm long fixing area is reserved at both ends of the inner heat fin for compression and fixing with the heat sink.

A 15 mm long fixing area is reserved at both ends of the outer heat fin for compression and fixing with the heat sink.

The difference S between the fixed area at the end of the inner thermal fins and the outer thermal fins is not less than 3 mm.

The ratio of the height A of the outer thermal fins to the width B of the middle arched structure is 0.3-0.8.

The vacuum tank body also includes a connecting pipe for vacuum pumping.

The vacuum pump suction system connected to the vacuum tank consists of two parts: a pre-pump system and a main pump system. The pre-pump system consists of a set of imported molecular pumps and a scroll dry pump. The main pump The system consists of an ion pump and a titanium sublimation pump. The vacuum protection system helps the equipment obtain the vacuum degree required for the test, mainly including vacuum pump exhaust system, vacuum valve, supporting pipeline and vacuum measuring device, etc.

The temperature guarantee of the vacuum pump exhaust system is realized by the temperature control unit in cooperation with the heat sink in the vacuum chamber. The interior of the cavity is composed of two sets of heat sinks, namely the bottom heat sink and the ring heat sink. The bottom heat sink is mainly used for large test samples and can be used as an auxiliary heat source. The heat exchange between the heat sink and the test piece is realized through the elastic heat conduction structure of the heat wing, which is a special structure specially designed to solve the temperature conduction in the ultra-high vacuum environment, and can ensure the uniformity of the heat conduction temperature of the test piece good.

The hot wings have high elasticity, wear resistance and ideal temperature conduction, and have good vacuum performance at the same time. While ensuring temperature conduction, they do not release gas and affect the decrease of vacuum degree.

The test workpiece is in elastic contact with a plurality of heat wings, the heat conduction area is large, the efficiency is high, and the heat conduction heat is uniform. The heat transfer between the heat sink and the test piece is guaranteed to the greatest extent without affecting the vacuum degree in the chamber. The size of the "hot wing" can be adjusted according to the size of the vacuum chamber itself and the size of the sample, and finally realize the soft connection heat conduction mode in the test chamber.

The heat fins are installed and pressed tightly on the inner wall of the heat sink to ensure that they are flat and tightly attached to the heat sink, thereby effectively improving the heat conduction efficiency. Put it as a whole on the cold and hot test platform in the vacuum test chamber, and verify the temperature conduction performance of the heat conduction device through the temperature of the heat sink, test sample mounting plate and test piece.

One end of the heat wing is close to the heat sink in the cabin, and the other end is a flexible structure, which can be changed arbitrarily according to the shape and structure of the test piece, so as to maximize the contact with the surface of the test piece, so as to better transfer heat to the test piece The product reaches the temperature specified in the test conditions. For samples of different volumes, the number of "hot fins" can be appropriately increased or decreased. For larger specimens, except for the "hot wings" in the annular area of the cabin, which can be attached to the sample, the bottom can also be used to control the temperature by installing "hot wings". The use of elastic heat conduction contacts can adapt to test workpieces of different sizes and shapes, and the use of contact heat conduction is faster and more efficient than space heat radiation and can easily control the temperature of the test workpiece. The rapid heating or cooling of the test workpiece can be realized, and the temperature requirements of the experiment on the test workpiece can be met with higher precision and efficiency.

In summary, the present invention has beneficial technical effects of good adaptability and high heat conduction efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the principle of the present invention;

Fig. 2 is a sectional view of the heat sink structure of the present invention;

Fig. 3 is a side view of the heat wing structure of the present invention;

In the figure: 1. Vacuum tank: 2. Sealing flange; 3. Test workpiece; 4. Heat sink; 5. Heat conduction oil unit; 6. Pipeline; 7. Vacuum pump exhaust system; Hot wing layer; 31. Workpiece mounting plate; 41. Bottom heat sink; 42. Ring heat sink; 71. Molecular pump; 72. Vortex dry pump; 73. Ion pump; 74. Titanium sublimation pump; 75. Self-pressurization Liquid nitrogen tank; 76. Vacuum valve; 81. Inner heat fin; 82. Outer heat fin; 311. Support flange.

Detailed ways

The technical solution will be further described below in conjunction with accompanying drawings 1-2 and specific embodiments, so as to help understand the content of the present invention.

As shown in Figure 1, the temperature control device for the high vacuum environment test piece includes a vacuum tank body 1, a sealing flange 2 for sealing the end of the vacuum tank body 1, and the inside of the vacuum tank body 1 for Test the heat sink 4 controlled by the temperature adjustment of the workpiece 3 and the pipeline 6 connected with the heat sink 4 and the heat transfer oil unit 5 .

The heat sink 4 is connected to the heat transfer oil unit 5 through pipelines, and the heat is transferred to the heat sink 4 through the heat transfer oil unit 5 , so as to realize the heating or cooling of the test workpiece 3 .

The vacuum tank body 1 is connected with the vacuum pump exhaust system 7, and the vacuum pump exhaust system 7 includes a pre-extraction system and a main extraction system; the pre-extraction system is composed of a molecular pump 71, a scroll dry pump 72 and a vacuum valve 76; The main pumping system consists of an ion pump 73 , a titanium sublimation pump 74 and a self-pressurized liquid nitrogen tank 75 . Vacuum pumping system 7 obtains the vacuum degree required for the test for the equipment.

The vacuum tank body 1 is a horizontal cylindrical structure.

As shown in FIG. 2 , the heat sink 4 includes a bottom heat sink 41 and an annular heat sink 42 ; the bottom heat sink 41 and the annular heat sink 42 form a test cavity for placing a test workpiece. Wherein the bottom heat sink 41 is mainly used for large test samples and can be used as an auxiliary heat source.

The test workpiece 3 is installed in the workpiece mounting plate 31 to test the cold welding between the test workpiece 3 and the workpiece mounting plate 31 under various temperature and vacuum conditions; the workpiece mounting plate 31 is a cylindrical member , which has a support flange 311 for positioning and heat conduction of the test workpiece 3 inside; the support flange 311 is in close contact with the test workpiece 3 and makes the bottom of the test workpiece 3 suspended.

A plurality of sets of heat fins 8 are installed on the surface of the heat sink 4 inside the test chamber for contacting the outer surface of the workpiece mounting plate 31 for heat conduction.

The heat fin 8 includes an inner heat fin 81 and an outer heat fin 82 whose two ends are overlapped and fixed on the surface of the heat sink; both ends of the inner heat fin and the outer heat fin are fixed in the middle The bow-shaped elastic structure with suspended protrusions.

As shown in FIG. 3 , the heat fins 8 are installed and pressed against the inner wall of the heat sink by means of heat fin bead 9 to ensure that they are flat and closely attached to the heat sink 4 , thereby effectively improving heat conduction efficiency.

The hot wings 8 are made of beryllium copper strips.

The arcuate top ends of the inner layer heat fins 81 and the outer layer heat fins 82 are separated by 2-3mm.

The cutting size of the beryllium copper strip is 100mm×10mm×0.2m.

The length of the fixing area at both ends of the inner heat fin 81 is 6 mm long for pressing and fixing with the heat sink 4 .

A 15 mm long fixing area is reserved at both ends of the outer heat fin for compression and fixing with the heat sink.

The difference S between the end fixing areas of the inner heat fins 81 and the outer heat fins 82 is 9mm.

The ratio of the height A of the outer heat fins to the width B of the middle arched structure is 0.45;

The vacuum tank body 1 also includes a connecting pipe for vacuum pumping.

The heat exchange between the heat sink 4 and the test workpiece 3 is realized through the elastic heat conduction structure of the heat wing 8, which is a special structure specially designed to solve the temperature conduction in the ultra-high vacuum environment, which can ensure the test The heat conduction temperature and uniformity of the workpiece 3 are good.

The hot fins 8 have high elasticity, wear resistance and ideal temperature conduction, and have good vacuum performance, while ensuring temperature conduction, they do not release gas and affect the decrease of vacuum degree.

The workpiece mounting plate 31 is in elastic contact with a plurality of heat wings 8, and has a large heat conduction area, high efficiency, and good heat conduction and heat uniformity. The heat transfer between the heat sink 4 and the test workpiece 3 is ensured to the greatest extent without affecting the vacuum degree in the chamber.

The above only discloses the preferred application examples of the present invention, and cannot limit the scope of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application and the content of the description of this invention belong to the patent of the present invention. range covered.

Claims (7)

1. The utility model provides a high vacuum environment test piece temperature control device which characterized in that: the device comprises a vacuum tank body, a sealing flange used for sealing the end part of the vacuum tank body, a heat sink used for testing the temperature regulation and control of a workpiece in the vacuum tank body, and a pipeline connected with the heat sink and an external temperature control unit;

the heat sink comprises a bottom heat sink and an annular heat sink; the bottom heat sink and the annular heat sink form a test cavity for placing a test workpiece;

a plurality of groups of heat fins for contacting with a test workpiece to conduct heat are arranged on the surface of the heat sink on the inner side of the test cavity;

the heat fins comprise an inner layer heat fin and an outer layer heat fin, and the two ends of the inner layer heat fin and the two ends of the outer layer heat fin are overlapped and fixed on the surface of the heat sink; the inner layer hot fin and the outer layer hot fin are both of arch-shaped elastic structures with two ends fixed with middle suspending bulges.

2. The temperature control device for the high vacuum environment test piece according to claim 1, characterized in that: the vacuum tank body is of a horizontal cylindrical structure.

3. The temperature control device for the high vacuum environment test piece according to claim 1, characterized in that: the heat wing is made of beryllium bronze strip.

4. The temperature control device for the high vacuum environment test piece according to claim 1, characterized in that: the interval between the top ends of the inner layer hot fin and the outer layer hot fin is 2-3 mm.

5. The temperature control device for the high vacuum environment test piece according to claim 3, characterized in that: the cutting size of the beryllium bronze strip is 100mm multiplied by 10mm multiplied by 0.2m.

6. The temperature control device for the high vacuum environment test piece according to claim 1, characterized in that: and fixing areas with the length of 6mm are reserved at two ends of the inner-layer heat fin for pressing and fixing with the heat sink.

7. The temperature control device for the high vacuum environment test piece according to claim 1, characterized in that: fixing areas with the length of 15mm are reserved at two ends of the outer layer heat fin for pressing and fixing with the heat sink.

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