Full-automatic low-temperature control equipment suitable for mechanical property experiment

Abstract

The invention discloses full-automatic low-temperature control equipment suitable for a mechanical property experiment, in particular to a low-temperature automatic control device in an experiment process, which comprises a liquid nitrogen tank, a low-temperature electromagnetic valve, a solid-state relay, a temperature process controller and a low-temperature experiment box. The low-temperature experiment box comprises a polystyrene box body, a transportation inner pipe, a thermocouple, a sliding heat preservation plate and a heat preservation observation opening. The liquid nitrogen tank is connected with a transportation inner pipe in the low-temperature environment experiment box through a transportation outer pipe, the transportation outer pipe is provided with a low-temperature electromagnetic valve, the low-temperature electromagnetic valve is connected with a solid-state relay and a power supply in series, the solid-state relay is electrically connected with a temperature process controller, and the temperature process controller is directly connected with the power supply; and a thermocouple is arranged in the low-temperature experiment box and is electrically connected with the temperature process controller. The device is cooperatively used with a mechanical property test instrument, so that the mechanical property test of the test piece from the normal temperature to the theoretical value of minus 196 DEG C can be realized, and the selection range of the size of the experimental test piece is greatly widened.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical experiments, and in particular to a fully automatic low-temperature control device suitable for mechanical property experiments. Background Art

[0002] Understanding the sensitivity of engineering materials and components to cryogenic environments and their mechanical properties at extremely low temperatures is a necessary condition to ensure that engineering materials and components can serve reliably in engineering applications in cryogenic environments. The key to accurately evaluating the experimental parameters of the mechanical properties of engineering materials and components at low temperatures is to ensure the stability of the experimental temperature. However, the current experimental temperature control device faces great challenges and difficulties in the implementation of low-temperature environments. The inventors have found that the existing experimental temperature control device in low-temperature environments has the following problems: Poor experimental temperature stability: The refrigeration system needs to be manually adjusted according to the real-time temperature of the experiment to achieve the purpose of cooling. It cannot guarantee that the experiment will continue stably at the preset temperature.

[0003] High consumption of human resources: Experimenters must always pay attention to the changes in real-time temperature during the experiment and make timely adjustments. The experimental process is too dependent on manual control.

[0004] The range of experimental specimen size selection is small: the size of existing low-temperature control devices is fixed, and often only experiments can be carried out on specimens with small volume, regular shape and small number.

[0005] The experimental device has poor flexibility: the experimental box provided is made of metal, which is inconvenient to disassemble, heavy and difficult to carry, requires a large amount of storage space, and has poor coordination with existing loading experimental equipment.

[0006] The manufacturing cost of the device is relatively high: the components of existing low-temperature control devices are mostly metal products, the material cost is relatively high, the device is relatively complex, the installation cost is relatively high, and the overall robustness is not high.

[0007] Small experimental observation space: No experimental observation window is set or it is only set on a single side of the device, and the range of the observation window is limited. During the experiment, it is impossible to fully observe or even impossible to observe the deformation, cracks and fractures of the specimen. Summary of the invention

[0008] In order to solve the problems existing in the existing low-temperature control devices, the present invention provides a fully automatic low-temperature control equipment suitable for mechanical properties experiments, which can not only realize a precise, stable and large-scale low-temperature experimental environment, but also automatically monitor the experimental temperature and adjust it. The temperature fluctuation error is less than 3°C, and it can meet the experimental requirements of specimens of various sizes. The equipment is simple to assemble, easy to move, and economical in cost. It can be used in conjunction with various types of mechanical properties testing instruments, and can clearly observe the mechanical properties testing process of the specimen in the whole process and from all angles.

[0009] In order to solve the above problems and achieve the purpose of the invention, the present invention adopts the following technical solutions: A fully automatic low-temperature control device suitable for mechanical property experiments includes a liquid nitrogen tank, a low-temperature solenoid valve, a solid-state relay, a temperature process controller and a low-temperature test box. The liquid nitrogen tank is connected to the low-temperature test box through an outer transport tube, an inner transport tube is arranged inside the low-temperature test box and connected to a port of the outer transport tube, and a low-temperature solenoid valve is arranged on the outer transport tube.

[0010] Furthermore, the low-temperature solenoid valve is in a closed state by default, and is connected in series with the solid-state relay and the power supply; the solid-state relay is in a disconnected state by default, and is electrically connected to the temperature process controller and the latter is directly connected to the power supply; a thermocouple is arranged inside the low-temperature experimental box and is electrically connected to the temperature process controller.

[0011] Beneficial effects: This solution inputs the preset experimental temperature of the low-temperature experiment box on the temperature process controller, so that the preset experimental temperature and the real-time experimental temperature in the low-temperature experiment box have a temperature difference, so that the solid-state relay changes from the default disconnected state to the closed state, and the low-temperature solenoid valve on the series circuit changes from the default closed state to the open state, so that the liquid nitrogen vapor enters the transport inner tube in the low-temperature experiment box from the liquid nitrogen tank through the transport outer tube, and the transport inner tube releases the liquid nitrogen vapor in the low-temperature experiment box to achieve the purpose of refrigeration; when the low-temperature experiment box reaches the preset temperature, the solid-state relay is disconnected, the low-temperature solenoid valve is closed, and no liquid nitrogen vapor enters the low-temperature experiment box, ensuring the temperature stability in the experiment box. At the same time, the electrical connection of the low-temperature solenoid valve, solid-state relay, temperature process controller and thermocouple makes the equipment easy to install and remove.

[0012] Furthermore, the outer transport tube and the inner transport tube are heat-insulating transport tubes, and metal hoses, plastic hoses and other transport tubes may be used. The connection between the outer transport tube and the liquid nitrogen tank and the low-temperature test box is filled with heat-insulating sealant.

[0013] Beneficial effects: The metal hose has good pressure resistance, sealing and mechanical properties, is in direct contact with the external environment, can be used in various complex liquid nitrogen transportation environments, and is not easily damaged; the plastic hose has good low-temperature resistance and good deformability, has a low purchase cost, and can be bent and fixed inside the low-temperature test box; the connection of the outer transport pipe is filled with thermal insulation sealant, which not only ensures the airtightness of the pipeline connection, but also makes the pipeline easy to dismantle and install.

[0014] Furthermore, the low-temperature experiment box includes a polystyrene box, a thermocouple, an inner transport tube, a pressure relief valve, a sliding insulation board and an insulation observation port; an opening is set in the middle of the two opposite sides of the polystyrene box, and the sliding insulation boards are respectively installed, and the sliding insulation boards are used in conjunction with the mechanical properties testing instrument by moving, and insulation materials are filled in the gaps; the inner transport tube is set at the lower end of the low-temperature experiment box, and a number of circular holes are set on it, which is fixed around the inside of the experiment box and releases nitrogen flow; the pressure relief valve is installed on the low-temperature experiment box; the insulation observation port is set on several observation surfaces of the low-temperature experiment box, and heat-insulating glass is respectively installed, and insulation sealant is filled at the joints.

[0015] The beneficial effects of adopting the above technical scheme are: the polystyrene box not only has good thermal insulation performance and low thermal conductivity, but also has an economical purchase price and convenient processing method, which avoids the loss of coldness of the low-temperature test box to the greatest extent, can realize large-scale processing and modification in a short time, and can accommodate test pieces of various sizes for experiments; the sliding insulation board on the mobile polystyrene box can enable the low-temperature test box to be used in conjunction with different types of mechanical properties testing instruments, thereby expanding the scope of use of this equipment, and the gaps are filled with insulation materials to ensure the overall air tightness of the low-temperature test box; the transport inner tube is arranged around the lower end of the low-temperature test box, and a number of circular holes are arranged on it, which can achieve a more uniform cooling effect; a pressure relief valve is installed on the polystyrene box to ensure the stability of the air pressure inside the low-temperature test box; several observation surfaces of the low-temperature test box are provided with observation windows with heat-insulating glass to ensure comprehensive observation of the test pieces during the experiment, and the glass gaps are filled with insulation sealant to ensure the air tightness of the low-temperature test box.

[0016] Furthermore, the temperature process controller has a visual control panel that can input and display the preset temperature of the experiment. It is electrically connected to the thermocouple in the low-temperature experimental box and displays the real-time temperature of the experiment. The temperature difference is converted into an electrical signal and output to the solid-state relay.

[0017] Beneficial effects: The temperature process controller displays the preset temperature and real-time temperature of the experiment at the same time, and can convert the temperature difference into an electrical signal and output it to the solid-state relay. The solid-state relay opens or closes according to the change in the difference, thereby controlling whether the low-temperature solenoid valve blocks the delivery of liquid nitrogen. It not only realizes the visualization of the experimental temperature difference, but also realizes the automatic delivery of liquid nitrogen and automatic control of the experimental temperature, freeing up human resources and avoiding temperature errors caused by manual temperature control. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the fully automatic low-temperature control equipment of the present invention.

[0019] In the figure: 1 liquid nitrogen tank; 2 low temperature solenoid valve; 3 solid state relay; 4 temperature process controller; 5 low temperature experiment box; 6 transport outer tube; 7 transport inner tube; 8 thermocouple; 9 polystyrene box; 10 pressure relief valve; 11 sliding insulation board; 12 insulation observation port; 13 power supply; 14 mechanical property testing instrument. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is described in detail below with reference to the accompanying drawings and examples.

[0021] The present invention inputs the preset temperature of the experiment on the temperature process controller 4, so that the real-time temperature in the low-temperature experiment box 5 and the preset temperature generate a temperature difference to control the solid-state relay 3 to close, further open the low-temperature solenoid valve 2, and allow the liquid nitrogen vapor to be transported from the liquid nitrogen tank 1 to the inside of the low-temperature experiment box 5 to reach the preset temperature of the experiment, and use the temperature difference to automatically control the operation of the low-temperature solenoid valve 2 to ensure the temperature stability inside the low-temperature experiment box 5. The present invention is used in conjunction with the mechanical properties testing instrument 14, the sliding insulation board 11 on the polystyrene box 9 is moved, the low-temperature experiment box 5 and the mechanical properties testing instrument 14 are adjusted to be fixed, the sliding insulation board 11 is closed, and the insulation material is filled in the gap, and the fully automatic low-temperature control equipment can start working.

[0022] Example: Mechanical experiments at low temperatures Assemble the present invention, prepare the test pieces to be tested, select a suitable mechanical property testing instrument 14, move the sliding insulation board 11 on the polystyrene box 9, combine the low-temperature test box 5 and the mechanical property testing instrument 14 together, close the sliding insulation board 11 in turn, fill the gap with insulation material, and ensure the air tightness of the test box.

[0023] Turn on the switch of the liquid nitrogen tank 1, connect the power supply 13 of the present invention, input the preset temperature of the experiment on the temperature process controller 4, the thermocouple 8 monitors the real-time temperature inside the low-temperature experiment box 5 and transmits it to the temperature process controller 4, the temperature process controller 4 converts the difference between the preset temperature and the real-time temperature into a closing signal and transmits it to the solid-state relay 3, the solid-state relay 3 is closed to energize the series circuit, so that the low-temperature solenoid valve 2 is changed from the default closed state to the open state, so that the liquid nitrogen vapor is transported from the liquid nitrogen tank 1 to the transport inner tube 7 in the low-temperature experiment box 5 through the transport outer tube 6, and the liquid nitrogen vapor is evenly released in the low-temperature experiment box 5 through the circular holes on the transport inner tube 7, thereby reducing the temperature inside the box.

[0024] When the real-time temperature in the low-temperature experiment box 5 is the same as the preset temperature, the temperature process controller 4 transmits the disconnection signal to the solid-state relay 3, the solid-state relay 3 is disconnected to open the series circuit in which it is located, the low-temperature solenoid valve 2 is closed, and the liquid nitrogen vapor supply is stopped, so that the temperature in the low-temperature experiment box 5 remains unchanged. At this time, the mechanical properties testing instrument 14 is turned on to start the experiment; as the experiment proceeds, the temperature in the low-temperature experiment box 5 begins to rise, and the appearance of the temperature difference reopens the low-temperature solenoid valve 2 again, thereby automatically ensuring the stability of the experimental temperature. At the same time, as the liquid nitrogen vapor continues to enter the low-temperature experiment box 5, the pressure in the box gradually increases, and the pressure relief valve 10 automatically opens and releases pressure. During the experiment, the deformation, cracks, fractures, etc. of the specimen can be observed through the insulation observation port 12, so that the whole process of the mechanical properties experiment can be clearly observed from all directions.

Claims

1. A fully automatic low temperature control device suitable for mechanical properties experiments, characterized by: The equipment includes a liquid nitrogen tank, a cryogenic solenoid valve, a solid-state relay, a temperature process controller and a cryogenic test box; the liquid nitrogen tank is connected to the cryogenic test box through an outer transport tube, and an inner transport tube is arranged inside the cryogenic test box to connect with a port of the outer transport tube; A low-temperature solenoid valve is arranged on the outer transport tube, and the low-temperature solenoid valve is in a closed state by default, and the low-temperature solenoid valve is connected in series with a solid-state relay and a power supply; the solid-state relay is in a disconnected state by default, and is electrically connected to a temperature process controller, and the temperature process controller is directly connected to a power supply; a thermocouple is arranged inside the low-temperature experimental box and is electrically connected to the temperature process controller.

2. The fully automatic low temperature control equipment suitable for mechanical properties experiments according to claim 1, characterized in that: The outer transport tube and the inner transport tube are heat-insulating transport tubes, and are made of metal hoses, plastic hoses and other materials. The connections between the outer transport tube and the liquid nitrogen tank and the low-temperature test box are filled with heat-insulating sealant.

3. The fully automatic low temperature control equipment suitable for mechanical properties experiments according to claim 1, characterized in that: The low-temperature experiment box includes a polystyrene box, a thermocouple, an inner transport tube, a pressure relief valve, a sliding insulation board and an insulation observation port; an opening is set in the middle of any two opposite sides of the polystyrene box, and a sliding insulation board is installed respectively. The sliding insulation board is used in coordination with a mechanical property testing instrument by moving, and insulation materials are filled in the gaps; the inner transport tube is arranged at the lower end of the low-temperature experiment box, and a plurality of circular holes are arranged on it, which is fixed around the inside of the experiment box and releases nitrogen flow; the pressure relief valve is installed on the low-temperature experiment box; the insulation observation port is arranged on a plurality of observation surfaces of the low-temperature experiment box, and heat-insulating glass for convenient observation is installed, and insulation sealant is filled at the joints.

4. The fully automatic low temperature control equipment suitable for mechanical properties experiments according to claim 1, characterized in that: The temperature process controller is provided with a visual control panel, which can input and display the preset temperature of the experiment. It is electrically connected to the thermocouple in the low-temperature experiment box and displays the real-time temperature of the experiment. The temperature difference is converted into an electrical signal and output to the solid-state relay.

5. The fully automatic low temperature control equipment suitable for mechanical properties experiments according to claim 1 is characterized in that: By inputting the preset temperature of the experiment on the temperature process controller, the real-time temperature in the low-temperature experiment box and the preset temperature produce a temperature difference, which controls the solid-state relay to close, opens the low-temperature solenoid valve, and allows liquid nitrogen vapor to be transported from the liquid nitrogen tank to the inside of the low-temperature experiment box to reach the preset temperature of the experiment. The temperature difference is used to automatically control the operation of the low-temperature solenoid valve to ensure the temperature stability inside the low-temperature experiment box; the fully automatic low-temperature control equipment is used in conjunction with the mechanical properties testing instrument, the sliding insulation board on the polystyrene box is moved, the low-temperature experiment box and the mechanical properties testing instrument are adjusted to be fixed, the sliding insulation board is closed, and the gap is filled with insulation material, and the fully automatic low-temperature control equipment can start working.

6. The fully automatic low temperature control equipment suitable for mechanical properties experiments according to claim 1, characterized in that: The mechanical experiment process at low temperature is as follows: After assembly, prepare the test pieces to be tested, select the appropriate mechanical properties test instrument, move the sliding insulation board on the polystyrene box, combine the low-temperature test box and the mechanical properties test instrument together, close the sliding insulation board in turn, fill the gap with insulation material, and ensure the airtightness of the test box; Turn on the liquid nitrogen tank switch, connect the power supply, input the preset temperature of the experiment on the temperature process controller, the thermocouple monitors the real-time temperature inside the low-temperature experiment box and transmits it to the temperature process controller, the temperature process controller converts the difference between the preset temperature and the real-time temperature into a closing signal and transmits it to the solid-state relay, the solid-state relay closes to energize the series circuit, and the low-temperature solenoid valve changes from the default closed state to the open state, so that the liquid nitrogen vapor is transported from the liquid nitrogen tank through the outer transport tube to the inner transport tube in the low-temperature experiment box, and the liquid nitrogen vapor is evenly released in the low-temperature experiment box through the circular holes on the inner transport tube, thereby reducing the temperature inside the box; When the real-time temperature in the low-temperature experiment box is the same as the preset temperature, the temperature process controller transmits a disconnection signal to the solid-state relay. The solid-state relay is disconnected to open the series circuit in which it is located, the low-temperature solenoid valve is closed, and the liquid nitrogen vapor supply is stopped, so that the temperature in the low-temperature experiment box remains unchanged. At this time, the mechanical properties testing instrument is turned on to start the experiment; as the experiment proceeds, the temperature in the low-temperature experiment box begins to rise, and the appearance of the temperature difference causes the low-temperature solenoid valve to reopen again, thereby automatically ensuring the stability of the experimental temperature; at the same time, as liquid nitrogen vapor continues to enter the low-temperature experiment box, the pressure in the box gradually increases, and the pressure relief valve automatically opens and releases the pressure; during the experiment, the deformation, cracks, and fractures of the specimen are observed through the insulation observation port, so that the entire process of the mechanical properties experiment can be clearly observed from all directions.

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