Refrigeration optimization system and refrigeration optimization method of low-temperature mechanical testing machine

Abstract

The invention provides a refrigeration optimization system and a refrigeration optimization method of a low-temperature mechanical testing machine, and relates to the technical field of refrigeration, the refrigeration optimization system comprises a testing machine main body, a test box, a self-pressurization liquid nitrogen tank and a temperature control device; the test box is placed on the testing machine main body; a to-be-tested sample is placed in the test box, and a low-temperature environment is provided for the to-be-tested sample through the test box; one end of the self-pressurization liquid nitrogen tank is communicated with one side of the test box, and the self-pressurization liquid nitrogen tank is used for providing cold source liquid nitrogen for the test box; the temperature control equipment is arranged in the test box and is in communication connection with an upper computer, and the temperature control equipment monitors the temperature in the test box in real time and feeds back the temperature to the upper computer in real time, so that the flow rate of cold source liquid nitrogen supplied to the test box by the self-pressurization liquid nitrogen tank is adjusted in real time, and then the temperature of the test box is controlled. According to the scheme, the refrigeration efficiency and the temperature stability of the whole system are improved.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and in particular to a refrigeration optimization system and an optimization refrigeration method for a low-temperature mechanical testing machine. Background Art

[0002] In the field of materials science and engineering, high-precision products and components need to be used in extremely low-temperature environments, and it is particularly important to accurately evaluate the low-temperature mechanical properties of products. Traditional liquid nitrogen refrigeration has problems such as low refrigeration efficiency, inaccurate temperature control, and waste of nitrogen resources. Refrigeration technology has certain limitations. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a refrigeration optimization system and an optimized refrigeration method for a low-temperature mechanical testing machine, so as to realize efficient transportation and precise control and regulation of liquid nitrogen, so as to ensure precise control and regulation of temperature in the system, improve refrigeration efficiency and reduce resource waste.

[0004] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0005] The present invention first provides a refrigeration optimization system for a low-temperature mechanical testing machine, comprising:

[0006] Testing machine body;

[0007] A test box, the test box is placed on the test machine body; the test box is suitable for placing the sample to be tested, and the test box provides a low temperature environment for the sample to be tested;

[0008] A self-pressurizing liquid nitrogen tank, one end of which is connected to one side of the test box, for providing cold source liquid nitrogen for the test box; and

[0009] A temperature control device is arranged in the test box and is communicatively connected with the host computer. The temperature control device monitors the temperature in the test box in real time and feeds back to the host computer in real time, so as to adjust the flow rate of the cold source liquid nitrogen supplied from the self-pressurized liquid nitrogen tank to the test box in real time, thereby controlling the temperature of the test box.

[0010] In one embodiment, the test chamber comprises:

[0011] Box;

[0012] Sample clamps are arranged in pairs, the sample clamps are arranged in pairs opposite to each other and spaced apart in the box, one end of one of the sample clamps is fixed in the box via a first connecting rod, and one end of the other sample clamp is fixed in the box via a second connecting rod; and

[0013] A switch door is covered on one side of the box body and is hinged to the side.

[0014] In one embodiment, the box body includes a first cavity and a second cavity arranged in sequence from the outside to the inside; wherein

[0015] The first cavity and the second cavity are spaced apart and form a circulation layer between the first cavity and the second cavity, and an air inlet is provided at corresponding positions on one side of the first cavity and on one side of the second cavity, an exhaust port is provided on one side of the first cavity, the second cavity is connected to one end of the self-pressurized liquid nitrogen tank through the air inlet, and the circulation layer is connected to the outside through the exhaust port.

[0016] In one embodiment, a second overflow port is provided at the bottom of the second cavity, a first overflow port is provided at the top of the second cavity and opposite to the second overflow port, and a connecting pipe is provided in the wall of the second cavity, through which the second cavity and the circulation layer are connected.

[0017] In one embodiment, a pressure control valve is provided on the air inlet pipeline connecting the self-pressurizing liquid nitrogen tank and the air inlet, and the pressure control valve is communicatively connected with the host computer for controlling the flow rate of the cold source liquid nitrogen supplied by the self-pressurizing liquid nitrogen tank to the second cavity.

[0018] In one embodiment, the test chamber further comprises at least one of the following:

[0019] A spray nozzle, the spray nozzle is disposed in the second cavity and fixedly connected to the air inlet pipe at the air inlet;

[0020] Circulation fans are arranged in pairs in the second cavity and the air outlets of the circulation fans are arranged opposite to the air inlet.

[0021] In one embodiment, through holes for the first connecting rod and the second connecting rod to pass through are provided at corresponding positions at both ends of the first cavity and at both ends of the second cavity; and / or,

[0022] The temperature control device is a temperature sensor, which is disposed in the second cavity and monitors the temperature in the second cavity in real time.

[0023] In one embodiment, the first cavity and the second cavity are both filled with a solid body of polyurethane foam material.

[0024] In one embodiment, the refrigeration optimization system of the cryogenic mechanical testing machine further includes:

[0025] A nitrogen recovery tank is connected to the circulation layer through the exhaust port; after the low-temperature test, the waste nitrogen in the second cavity enters the circulation layer through the second overflow port, the connecting pipe and the first overflow port in sequence, and enters the nitrogen recovery tank through the exhaust port after circulating around the second cavity in the circulation layer.

[0026] The present invention also provides a refrigeration optimization method based on the refrigeration optimization system of the cryogenic mechanical testing machine, comprising:

[0027] Step 11, after fixing the sample to be tested with a sample fixture, close the switch door of the test box, and set up an image acquisition device outside facing the observation window according to the requirements of the low-temperature mechanical test;

[0028] Step 12: Before the test, open the pressure control valve on the air inlet pipe connected to the self-pressurized liquid nitrogen tank, start the host computer and perform a self-check to ensure that all components are working properly;

[0029] Step 13, after the host computer sets the target temperature of the test box, the low temperature test is started, and liquid nitrogen is transported from the air inlet pipe through the pressure control valve, and is vaporized into nitrogen in the air inlet pipe and evenly sprayed into the second cavity of the test box through the spray nozzle;

[0030] Step 14, simultaneously starting the circulation fan in the second cavity to make the air flow in the cavity and ensure that the temperature in the cavity is evenly distributed;

[0031] Step 15, continuously monitoring the temperature in the second cavity through a temperature sensor and feeding it back to the host computer, and controlling the nitrogen flow rate by adjusting the opening of the pressure control valve to ensure that the temperature is stable within the set target temperature range;

[0032] Step 16, after the test is completed, the waste nitrogen with a certain low temperature enters the circulation layer through the second overflow port, the connecting pipe and the first overflow port in sequence, and circulates around the second cavity in the circulation layer for one cycle before entering the nitrogen recovery tank through the exhaust port, and is re-constituted into liquid nitrogen through the nitrogen recovery tank.

[0033] The above solution of the present invention includes at least the following beneficial effects:

[0034] 1. A low-temperature test chamber is designed for axial fatigue tests on special or universal material testing machines, and the test chamber body is a multi-layer insulation shell setting, which reduces the low energy loss and temperature fluctuations during the entire low-temperature test process.

[0035] 2. The temperature in the test chamber is monitored and fed back in real time through the temperature control equipment, and the nitrogen flow rate supplied to the test chamber is sensitively adjusted to ensure accurate control of the test chamber temperature and improve the temperature stability of the test chamber during the low-temperature test.

[0036] 3. The high-concentration waste nitrogen after the test is recovered through the nitrogen recovery tank, and the high-concentration waste nitrogen is used to re-prepare liquid nitrogen. While forming a complete refrigeration system integrating nitrogen recycling and production and use, it can also avoid environmental pollution and realize the recycling of resources.

[0037] 4. The low-temperature nitrogen is evenly distributed and circulated in the test chamber through the spray nozzle and the circulating fan, so that the temperature and space uniformity in the test chamber meet the test conditions.

[0038] It should be understood that the implementation of any embodiment of the present invention does not mean that multiple or all of the above-mentioned beneficial effects must be possessed or achieved at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0040] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment in size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0041] Figure 1 is a front view of a refrigeration optimization system of a cryogenic mechanical testing machine provided by an embodiment of the present invention;

[0042] Figure 2 is a cross-sectional view of a test box provided by an optional embodiment of the present invention;

[0043] Figure 3 It is a front view of a test box provided by an optional embodiment of the present invention.

[0044] Description of Figure Numbers:

[0045] 1. Testing machine body; 21. First connecting rod; 22. Second connecting rod; 3. Sample fixture; 4. Test box; 401. Through hole; 402. First cavity; 403. Circulation layer; 404. Second cavity; 405. First overflow port; 406. Connecting pipe; 407. Second overflow port; 408. Polyurethane foam material; 5. Open / close door; 6. Sealing ring; 7. Nitrogen recovery tank; 8. Check valve; 9. Exhaust pipe; 10. Self-pressurized liquid nitrogen tank; 11. Inlet pipe; 12. Pressure control valve; 13. Exhaust port; 14. Inlet port; 15. Spray nozzle; 16. Circulation fan; 17. Temperature sensor; 18. Observation window; 19. Hinge; 20. Support.

[0046] The same or corresponding symbols in the drawings indicate the same or corresponding parts. DETAILED DESCRIPTION

[0047] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0048] In the description of the present invention, it is to be understood that the terms "include / comprise", "consist of" or any other variation thereof are intended to cover non-exclusive inclusion, so that a product, device, process or method including a series of elements includes not only those elements, but also other elements not explicitly listed when necessary, or also includes elements inherent to such product, device, process or method. In the absence of further restrictions, the elements defined by the phrases "include / comprise...", "consist of..." do not exclude the presence of other identical elements in the product, device, process or method including the elements.

[0049] It should also be understood that terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “top”, “bottom”, “inside” and “outside” to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the device, component or structure referred to must have a specific direction, be constructed or operate in a specific direction, and should not be understood as a limitation on the present invention.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] First of all, it should be noted that the refrigeration optimization system provided in the following embodiments of the present invention is suitable for axial mechanical property testing of metal materials under low temperature conditions, and provides an efficient and environmentally friendly low temperature testing solution for scientific research on metal materials.

[0053] like Figures 1 to 2 As shown, an embodiment of the present invention provides a refrigeration optimization system for a low-temperature mechanical testing machine, comprising:

[0054] Testing machine body 1;

[0055] The test box 4 is placed on the test machine body 1; the test box 4 is used to place the sample to be tested, and the test box 4 provides a low temperature environment for the sample to be tested;

[0056] A self-pressurizing liquid nitrogen tank 10, one end of which is connected to one side of the test box 4, for providing cold source liquid nitrogen for the test box 4; and

[0057] The temperature control device is arranged in the test box 4 and is connected to the host computer for communication. The temperature control device monitors the temperature in the test box 4 in real time and feeds back to the host computer in real time, so as to adjust the flow rate of the cold source liquid nitrogen supplied to the test box 4 from the pressurized liquid nitrogen tank 10 in real time, thereby controlling the temperature of the test box 4.

[0058] In this embodiment, the testing machine body 1 is a testing machine for axial mechanical testing, on which a testing box 4 is placed. The testing box 4 is insulated and heat-insulated in a sealed state, providing a stable low-temperature environment for the sample to be tested, ensuring that the low-temperature test can be carried out smoothly.

[0059] The self-pressurizing liquid nitrogen tank 10 is a refrigeration source, which contains liquid nitrogen and vaporizes the low-temperature liquid nitrogen into low-temperature nitrogen gas by self-pressurization and transports it to the test box 4.

[0060] Furthermore, a temperature control device is provided in the test box 4, which monitors the temperature in the test box 4 in real time. At the same time, the temperature control device is connected to the host computer for communication, and synchronizes the real-time monitored temperature in the test box 4 to the host computer in real time, so as to control the flow rate of vaporized nitrogen supplied from the pressurized liquid nitrogen tank 10 to the test box 4, thereby realizing the control of the temperature in the test box 4 and achieving rapid cooling. At the same time, the temperature in the test box 4 is monitored and fed back by the temperature control device in real time to ensure precise temperature control, thereby improving the temperature stability of the test box 4 during the low-temperature test.

[0061] like Figure 1 As shown, in an optional embodiment of the present invention, the test box 4 first includes:

[0062] Box.

[0063] In this embodiment, the box body is placed as a whole on the testing machine body 1. Preferably, four supports 20 are evenly arranged on the bottom of the box body, one end of the support 20 is fixedly connected to the bottom of the box body, and the other end of the support 20 is placed on the testing machine body 1, so that the bottom of the box body of the test box 4 is suspended on the testing machine body 1; more preferably, the support 20 can be set as a four-corner support with adjustable height, the adjustable height setting is for facilitating the test operation, and the four corners are set to ensure stability during placement.

[0064] In an optional embodiment of the present invention, the test box 4 further includes:

[0065] The sample clamps 3 are arranged in pairs, and the sample clamps 3 are arranged in pairs opposite to each other and at intervals in the box body. One end of one of the sample clamps 3 is fixed in the box body by a first connecting rod 21, and one end of the other sample clamp in the pair is fixed in the box body by a second connecting rod 22.

[0066] In this embodiment, the sample clamps 3 are arranged in pairs and opposite to each other in the box body, and the oppositely arranged sample clamps 3 are arranged at intervals to facilitate fixing the samples to be tested; a first connecting rod 21 and a second connecting rod 22 are arranged opposite to each other on the testing machine body 1, and the paired sample clamps 3, the first connecting rod 21 and the second connecting rod 22 are distributed along the axis of the testing machine body 1; wherein, one end of the first connecting rod 21 is fixed to one end of the testing machine body 1, and the other end of the first connecting rod 21 penetrates into the box body and is fixedly connected to one end of one of the paired sample clamps 3; one end of the second connecting rod 22 is fixed to the other end of the testing machine body 1, and the other end of the second connecting rod 22 penetrates into the box body and is fixedly connected to one end of the other sample clamp in the paired sample clamp 3; preferably, the first connecting rod 21 and the second connecting rod 22 are sealingly sleeved on the box body to ensure the sealing of the box body.

[0067] In an optional embodiment of the present invention, the test box 4 further includes:

[0068] The switch door 5 covers one side of the box body and is hinged to the side.

[0069] like Figure 3 As shown, the switch door 5 is arranged on one side of the box body, which side can be the front side of the box body, and an opening is opened on the front side, the switch door 5 covers the opening, and one side of the switch door 5 can be hinged and fixed to the front side of the box body by a hinge 19, so as to place the sample to be tested; preferably, a sealing ring 6 is fixedly connected to the side surface of the switch door 5 facing the inside of the box body, and more preferably, the sealing ring 6 can be made of fluororubber; when the switch door 5 is closed, the sealing ring 6 surrounds the outer periphery of the opening on the front side to seal the contact surface between the switch door 5 and the box body to ensure the temperature inside the box body.

[0070] In an achievable example of the present invention, an observation window 18 is provided on the front of the switch door 5, and the observation window 18 is made of glass, so that according to the needs of the low-temperature test, the changes of the sample to be tested in the box can be observed from the outside of the box through the observation window 18, or image acquisition can be performed by an image acquisition device installed in front of the observation window 18 to meet the relevant needs of collecting process images, in-situ tests, etc. in the mechanical properties test of the specimen; preferably, the observation window 18 can be a double-layer glass structure, and the interior of the double-layer glass structure is in a vacuum state without heat transfer, so as to avoid affecting the thermal insulation performance of the test box 4, thereby ensuring the stability of the low-temperature environment in the box.

[0071] like Figure 2 As shown, in an optional embodiment of the present invention, the shell between the inner wall and the outer surface of the box is composed of a multi-layer thermal insulation structure, and the multi-layer thermal insulation structure is arranged to improve the thermal insulation performance and temperature stability of the system and reduce the low energy loss during the entire test process; specifically, the multi-layer thermal insulation structure of the box includes a first cavity 402 and a second cavity 404 arranged in sequence from the outside to the inside; wherein the first cavity 402 and the second cavity 404 are arranged at intervals and a circulation layer 403 is formed between the first cavity 402 and the second cavity 404, and an air inlet 14 is provided at corresponding positions on one side of the first cavity 402 and on one side of the second cavity 404, an exhaust port 13 is provided on one side of the first cavity 402, and the second cavity 404 is connected to one end of the self-pressurized liquid nitrogen tank 10 through the air inlet 14, and the circulation layer 403 is connected to the outside through the exhaust port 13.

[0072] In this embodiment, the second cavity 404 is arranged in the first cavity 402, and the second cavity 404 and the first cavity 402 are spaced apart to form a hollow circulation layer 403 in the middle to form a multi-layer insulation structure of the box; in an achievable example of the present invention, the first cavity 402 and the second cavity 404 are both formed by solid filling of hard polyurethane foam material 408, which further ensures the temperature inside the box, and thus ensures the stability of the low-temperature environment inside the box.

[0073] Here, the air inlet 14 runs through the first cavity 402 and the second cavity 404 to ensure that the low-temperature vaporized nitrogen is directly supplied into the second cavity 404 after the air inlet pipe 11 of the self-pressurized liquid nitrogen tank 10 passes through the air inlet 14, providing a low-temperature environment for the sample to be tested, and the air inlet 14 is opened on the other side of the first cavity 402 and the upper end of the second cavity 404, so as to supply the low-temperature vaporized nitrogen from the top of the second cavity 404; the exhaust port 13 is arranged on the first cavity 402 and communicated with the circulation layer 403, and the exhaust port 13 is opened on the other side of the lower end of the first cavity 402, and is connected to the outside through the air outlet pipe 9.

[0074] In an optional embodiment of the present invention, through holes 401 for the first connecting rod 21 and the second connecting rod 22 to pass through are provided at corresponding positions at both ends of the first cavity 402 and at both ends of the second cavity 404; here, through holes 401 are provided at the upper and lower ends of the first cavity 402 and the upper and lower ends of the second cavity 404, and the through holes 401 are respectively sealed and sleeved with the first connecting rod 21 and the second connecting rod 22, which can ensure the sealing of the box while fixing the second cavity 404, thereby realizing seamless connection between the low-temperature box and the testing machine; preferably, the sealing sleeve gap between the through hole 401 and the first connecting rod 21 and the second connecting rod 22 can be filled with thermal insulating asbestos to further improve the sealing of the box.

[0075] In an optional embodiment of the present invention, a second overflow port 407 is provided at the bottom of the second cavity 404 , and a first overflow port 405 is provided at the top of the second cavity 404 at a position opposite to the second overflow port 407 .

[0076] In this embodiment, the second overflow port 407 is opened on one side of the bottom of the second cavity 404, and the first overflow port 405 is opened on one side of the top of the second cavity 404, and the first overflow port 405 and the second overflow port 407 are positioned opposite to each other; preferably, the first overflow port 405 and the second overflow port 407 are connected through a vertical connecting pipe 406 arranged in the left side wall of the second cavity 404.

[0077] During the entire low-temperature test process, driven by the pressure of the nitrogen gas transported to the second cavity 404 of the cryogenic box 4, the vaporized nitrogen gas acts in the second cavity 404 for a period of time, enters the connecting pipe 406 through the second overflow port 407, flows out from the first overflow port 405, and reaches the circulation layer 403; here, the nitrogen gas that has acted for a period of time enters the circulation layer 403 mainly depends on the air pressure in the second cavity 404, the designed second overflow port 407, the connecting pipe 406 and the first overflow port 405, thereby improving the effectiveness of the nitrogen circulation flow in the second cavity 404 of the system.

[0078] In an optional embodiment of the present invention, the temperature control device is a temperature sensor 17 , which is disposed in the second cavity 404 and monitors the temperature in the second cavity 404 in real time.

[0079] like Figure 2 As shown, in this embodiment, the temperature control device can be a temperature sensor 17, which is arranged on the side wall inside the second cavity 404 and is communicated with the host computer for real-time monitoring and feedback of the temperature inside the second cavity 404, so as to control the flow rate of nitrogen supplied from the pressurized liquid nitrogen tank 10, and then accurately control the temperature inside the second cavity 404.

[0080] In an optional embodiment of the present invention, a pressure control valve 12 is provided on the air inlet pipe 11 connecting the self-pressurized liquid nitrogen tank 10 and the air inlet 14. The pressure control valve 12 is communicatively connected to the host computer and is used to control the flow rate of the cold source liquid nitrogen supplied from the self-pressurized liquid nitrogen tank 10 to the second cavity 404.

[0081] In this embodiment, liquid nitrogen is stored in the self-pressurized liquid nitrogen tank 10, and the liquid nitrogen outlet of the self-pressurized liquid nitrogen tank 10 is connected with the first cavity 402 and the air inlet 14 on the second cavity 404 through the air inlet pipe 11; after the low-temperature test starts, the liquid nitrogen flows out from the liquid nitrogen outlet of the pressurized liquid nitrogen tank 10, and the liquid nitrogen is transported through the air inlet pipe 11, and is converted from liquid to low-temperature nitrogen during the transportation process. The low-temperature nitrogen enters the second cavity 404 through the air inlet 14 to control the temperature in the cavity to drop rapidly to the required temperature.

[0082] Here, the pressure control valve 12 can be arranged on the air intake pipe 11 near the air intake port 14 , so as to adjust the delivery amount of the low-temperature nitrogen by adjusting the opening of the pressure control valve 12 , thereby accurately controlling the temperature in the second cavity 404 .

[0083] In an optional embodiment of the present invention, the test box 4 further includes at least one of the following:

[0084] A spray nozzle 15, the spray nozzle 15 is disposed in the second cavity 404 and fixedly connected to the air inlet pipe 11 at the air inlet 14;

[0085] The circulation fans 16 are arranged in pairs in the second cavity 404 and the air outlets of the circulation fans 16 are arranged opposite to the air inlet 14 .

[0086] In this embodiment, the spray nozzle 15 is fixedly connected to one end of the air inlet pipe 11. When liquid nitrogen is used as a low-temperature cooling source and is input into the second cavity 404 through the air inlet pipe 11, the spray nozzle 15 is sprayed in the entire second cavity 404 to control the temperature in the second cavity 404 to quickly drop to the required temperature; here, the spray nozzle 15 can also be replaced by two nitrogen spray heads so that the vaporized nitrogen can be sprayed in the entire second cavity 404 in the form of mist.

[0087] The circulating fans 16 are arranged in pairs, are arranged at intervals and fixedly connected to the inner wall of the second cavity 404, and are arranged relative to the air inlet 14; preferably, they are arranged opposite to the spray nozzle 15. During the entire low-temperature test process, the circulating fans 16 are in operation to enable the flow and convection of air and low-temperature nitrogen in the second cavity 404, so that the low-temperature nitrogen can be evenly distributed in the second cavity 404, so as to evenly adjust the internal temperature of the second cavity 404, thereby ensuring that the temperature and spatial uniformity in the second cavity 404 meet the test condition requirements.

[0088] In an optional embodiment of the present invention, the refrigeration optimization system of the cryogenic mechanical testing machine further includes:

[0089] The nitrogen recovery equipment, such as a nitrogen recovery tank 7, is connected to the circulation layer 403 through the exhaust port 13. After the low temperature test, the waste nitrogen in the second cavity 404 enters the circulation layer 403 through the second overflow port 407, the connecting pipe 406 and the first overflow port 405 in sequence, and enters the nitrogen recovery tank 7 through the exhaust port 13 after circulating around the second cavity 404 in the circulation layer 403 for one cycle.

[0090] In this embodiment, the nitrogen recovery tank 7 is connected to the exhaust port 13 through the outlet pipe 9. The nitrogen recovery tank 7 recovers the high-concentration waste nitrogen after the test in the second cavity 404, and at the same time, the high-concentration waste nitrogen is used to re-prepare liquid nitrogen inside the nitrogen recovery tank 7 to achieve the recycling of resources.

[0091] Here, the nitrogen recovery tank 7 can be a small gas compression recovery device, which recovers the high-concentration waste nitrogen after the test by gas compression to form a complete refrigeration system integrating nitrogen recycling and production.

[0092] The specific working process of the refrigeration optimization system of the cryogenic mechanical testing machine provided by the above embodiment of the present invention when performing a cryogenic test is as follows:

[0093] Step 11, before conducting the low-temperature mechanical properties test, fix the sample to be tested with the sample fixture 3 and close the switch door 5 of the test box 4; and further set up an image acquisition device outside facing the observation window 18 according to the needs of the low-temperature test;

[0094] Step 12, before the test, open the pressure control valve 12 on the air inlet pipe 11 connected to the self-pressurized liquid nitrogen tank 10, and start the host computer and perform a self-check to ensure that all components are working properly;

[0095] Step 13, after the host computer sets the target temperature of the test box 4, the low temperature test is started, and liquid nitrogen is transported from the air inlet pipe 11 through the pressure control valve 12, and is vaporized into nitrogen in the air inlet pipe 11 and evenly sprayed into the second cavity 404 of the test box 4 through the spray nozzle 15, so as to quickly reduce the temperature in the second cavity 404 to the set target temperature;

[0096] Step 14, simultaneously start the circulation fan 16 in the second cavity 404 to make the air flow in the cavity and ensure that the temperature in the cavity is evenly distributed;

[0097] Step 15, continuously monitor the temperature in the second cavity 404 through the temperature sensor 17 and feed it back to the host computer, and control the nitrogen flow rate by adjusting the opening of the pressure control valve 12 to ensure that the temperature is stable within the set target temperature range;

[0098] Step 16, after the test is completed, the waste nitrogen with a certain low temperature enters the circulation layer 403 through the second overflow port 407, the connecting pipe 406 and the first overflow port 405 in sequence, and circulates around the second cavity 404 in the circulation layer 403 for one cycle before entering the nitrogen recovery tank 7 through the exhaust port 13, and is re-constituted into liquid nitrogen through the nitrogen recovery tank 7.

[0099] The refrigeration optimization system in the above embodiment improves the thermal insulation performance and temperature stability of the entire system by designing the test box as a multi-layer shell structure with a nitrogen circulation layer in the middle; the self-pressurized liquid nitrogen tank 10 cooperates with the temperature sensor 17 and the pressure control valve 12 to control the flow rate of nitrogen, so as to achieve rapid cooling of the test box 4 and precise temperature control. At the same time, with the use of the circulating fan 6 and / or the spray nozzle 15, the temperature and air field uniformity in the test box 4 can be adjusted; the waste nitrogen after the test is recovered by the nitrogen recovery tank 7, and the waste nitrogen is compressed by gas compression to re-prepare liquid nitrogen. On the one hand, it can avoid the waste nitrogen from polluting the environment, and on the other hand, it also realizes the recycling of resources.

[0100] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A refrigeration optimization system for a cryogenic mechanical testing machine, It is characterized in that include: Testing machine body (1); A test box (4), the test box (4) being placed on the test machine body (1); the test box (4) is suitable for placing a sample to be tested, and the test box (4) provides a low-temperature environment for the sample to be tested; A self-pressurizing liquid nitrogen tank (10), one end of which is in communication with one side of the test box (4) and is used to provide cold source liquid nitrogen for the test box (4); as well as A temperature control device is provided in the test box (4) and is communicatively connected to a host computer. The temperature control device monitors the temperature in the test box (4) in real time and provides feedback to the host computer in real time, so as to adjust in real time the flow rate of the cold source liquid nitrogen supplied from the self-pressurized liquid nitrogen tank (10) to the test box (4), thereby controlling the temperature in the test box (4).

2. The refrigeration optimization system for a cryogenic mechanical testing machine according to claim 1, It is characterized in that The test box (4) comprises: Box; Sample clamps (3) are arranged in pairs, the sample clamps (3) are arranged opposite to each other and spaced apart in the box, one end of one of the sample clamps (3) is fixed to the box via a first connecting rod (21), and one end of the other of the sample clamps (3) is fixed to the box via a second connecting rod (22); and A switch door (5), the switch door (5) covers one side of the box body and is hinged to the side.

3. The refrigeration optimization system for a cryogenic mechanical testing machine according to claim 2, It is characterized in that The box comprises a first cavity (402) and a second cavity (404) which are arranged in sequence from the outside to the inside; wherein the first cavity (402) and the second cavity (404) are arranged at intervals and a circulation layer (403) is formed between the first cavity (402) and the second cavity (404), and an air inlet (14) is provided at corresponding positions on one side of the first cavity (402) and on one side of the second cavity (404), an exhaust port (13) is provided on one side of the first cavity (402), the interior of the second cavity (404) is communicated with one end of the self-pressurizing liquid nitrogen tank (10) through the air inlet (14), and the circulation layer (403) is communicated with the outside through the exhaust port (13).

4. The refrigeration optimization system for a cryogenic mechanical testing machine according to claim 3, It is characterized in that A second overflow port (407) is provided at the bottom of the second cavity (404), a first overflow port (405) is provided at the top of the second cavity (404) and at a position opposite to the second overflow port (407), and a connecting pipe (406) is provided in the wall of the second cavity (404), and the second cavity (404) and the circulation layer (403) are connected via the connecting pipe (406).

5. The refrigeration optimization system for a cryogenic mechanical testing machine according to claim 3, It is characterized in that A pressure control valve (12) is provided on an air intake pipe (11) connecting the self-pressurizing liquid nitrogen tank (10) and the air intake port (14); the pressure control valve (12) is communicatively connected to the host computer and is used to control the flow rate of the cold source liquid nitrogen supplied by the self-pressurizing liquid nitrogen tank (10) to the second cavity (404).

6. The refrigeration optimization system for a cryogenic mechanical testing machine according to claim 3, It is characterized in that The test box (4) further comprises at least one of the following: a spray nozzle (15), the spray nozzle (15) being arranged in the second cavity (404) and fixedly connected to the air intake pipe (11) at the air intake port (14); Circulation fans (16), the circulation fans (16) being arranged in pairs in the second cavity (404) and the air outlets of the circulation fans (16) being arranged opposite to the air inlet (14).

7. The refrigeration optimization system for a cryogenic mechanical testing machine according to claim 3, It is characterized in that Through holes (401) for the first connecting rod (21) and the second connecting rod (22) to pass through are provided at corresponding positions at both ends of the first cavity (402) and at both ends of the second cavity (404).

8. The refrigeration optimization system for a cryogenic mechanical testing machine according to claim 3, It is characterized in that The first cavity (402) and the second cavity (404) are both filled with a polyurethane foam material; and / or, The temperature control device comprises a temperature sensor (17), wherein the temperature sensor (17) is arranged in the second cavity (404) and monitors the temperature in the second cavity (404) in real time.

9. The refrigeration optimization system for a cryogenic mechanical testing machine according to claim 4, It is characterized in that Also includes: A nitrogen recovery tank (7), the nitrogen recovery tank (7) being connected to the circulation layer (403) via the exhaust port (13); after the low-temperature test is completed, the waste nitrogen in the second cavity (404) enters the circulation layer (403) via the second overflow port (407), the connecting pipe (406) and the first overflow port (405) in sequence, and enters the nitrogen recovery tank (7) via the exhaust port (13) after circulating around the second cavity (404) in the circulation layer (403) for one cycle.

10. A refrigeration optimization method based on the refrigeration optimization system of the cryogenic mechanical testing machine according to any one of claims 1 to 9, It is characterized in that include: Step 11, after fixing the sample to be tested with a sample fixture, close the switch door of the test box, and set up an image acquisition device outside facing the observation window according to the requirements of the low-temperature mechanical test; Step 12, before the test, open the pressure control valve (12) on the air inlet pipe (11) connected to the self-pressurized liquid nitrogen tank (10), and at the same time start the host computer and perform a self-check to ensure that all components are working properly; Step 13, after the host computer sets the target temperature of the test box (4), the low temperature test is started, and liquid nitrogen is transported from the air inlet pipe (11) through the pressure control valve (12), and is vaporized into nitrogen gas in the air inlet pipe (11) and evenly sprayed into the second cavity (404) of the test box (4) through the spray nozzle (15); Step 14, simultaneously starting the circulation fan (16) in the second cavity (404) to allow air to flow in the cavity to ensure that the temperature in the cavity is evenly distributed; Step 15, continuously monitoring the temperature in the second cavity (404) through the temperature sensor (17) and feeding back to the host computer, and controlling the nitrogen flow rate by adjusting the opening of the pressure control valve (12) to ensure that the temperature is stable within the set target temperature range; Step 16, after the test is completed, the waste nitrogen with a certain low temperature enters the circulation layer (403) through the second overflow port (407), the connecting pipe (406) and the first overflow port (405) in sequence, and circulates around the second cavity (404) in the circulation layer (403) for one cycle before entering the nitrogen recovery tank (7) through the exhaust port (13), and is re-converted into liquid nitrogen through the nitrogen recovery tank (7).

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