Cascade control system for ultralow-temperature test chamber

Abstract

The utility model relates to an ultralow temperature test chamber cascade control system, which comprises a main controller and an auxiliary controller, the main controller is electrically connected with the auxiliary controller through a communication line, the main controller is connected with a high-precision sensor module, and the auxiliary controller is connected with an actuating mechanism; the main controller is connected with a refrigerant detection module and a fault diagnosis module, and the auxiliary controller is connected with an automatic alarm module. The executing mechanism comprises a compressor, a condenser, an electronic expansion valve, an evaporator and a gas-liquid separator; an outlet pipeline of the compressor is connected with an inlet pipeline of the condenser, an outlet pipeline of the condenser is connected with an inlet pipeline of the electronic expansion valve, an outlet pipeline of the electronic expansion valve is connected with an inlet pipeline of the evaporator, and an outlet pipeline of the evaporator is connected with an inlet pipeline of the compressor through the gas-liquid separator. According to the utility model, accurate control and stable adjustment of the internal temperature of the test box can be realized, real-time monitoring and fault diagnosis functions are realized, and abnormal conditions can be found and handled in time.

Description

[Technical field]

[0001] The utility model relates to the technical field of test chamber control systems, in particular to a cascade control system for an ultra-low temperature test chamber. [Background Technology]

[0002] Ultra-low temperature test chambers are used to test the performance parameters of electrical, electronic, and other product materials in high- and low-temperature environments, or in constant test environments. Their low-temperature range extends from 0°C to -80°C. Ultra-low temperature test chambers can be used to assess and determine the suitability of electrical, electronic, or other materials for storage and use in low-temperature environments generated by temperature cycles. Forced air circulation is also used to maintain temperature uniformity within the chamber.

[0003] For example, Chinese patent CN211148223U discloses an ultra-low temperature test chamber capable of temperature cycling, which comprises: a multi-layered box body, a cooling system, and a control system; the box body comprises a steel plate outer box that supports and protects the equipment, an insulation box for insulation, and an inner box for carrying test pieces; the steel plate outer box is formed by bending and welding multiple layers of 304 stainless steel, with reinforcing ribs at the stress-bearing positions; the insulation box is arranged inside the steel plate outer box, and the inner box is arranged inside the insulation box; the cooling system is arranged inside the insulation box; and the control system is control-connected to the cooling system.

[0004] However, this technology has the following problems: this technology uses a temperature sensor that cannot accurately collect the temperature of each part of the test chamber; this technology uses a single-stage control system that cannot achieve precise control of the temperature in the test chamber.

[0005] Based on this, the utility model designs a cascade control system of an ultra-low temperature test chamber to solve the above problems. [Utility Model Content]

[0006] In view of the above-mentioned shortcomings of the prior art, the utility model provides a cascade control system for an ultra-low temperature test chamber.

[0007] To achieve the above objectives, a cascade control system for an ultra-low temperature test chamber is designed, comprising a main controller and a sub-controller, the main controller and the sub-controller being electrically connected via a communication line, the main controller being connected to a high-precision sensor module for detecting the temperature inside the test chamber, and the sub-controller being connected to an actuator for adjusting the temperature inside the test chamber;

[0008] The main controller is connected to a refrigerant detection module for refrigerant quality detection and a fault diagnosis module for judging the high-precision sensor module, and the sub-controller is connected to an automatic alarm module for alarm reminder;

[0009] The actuator includes a compressor, a condenser, an electronic expansion valve, an evaporator and a gas-liquid separator; the outlet pipe of the compressor is connected to the inlet pipe of the condenser, the outlet pipe of the condenser is connected to the inlet pipe of the electronic expansion valve, the outlet pipe of the electronic expansion valve is connected to the inlet pipe of the evaporator, and the outlet pipe of the evaporator is connected to the inlet pipe of the compressor through the gas-liquid separator.

[0010] Furthermore, the sub-controller and the compressor, condenser, electronic expansion valve, and evaporator are all electrically connected to the main controller.

[0011] Furthermore, the evaporator is connected to the refrigerant detection module and the circulation mechanism.

[0012] Furthermore, the high-precision sensor module includes temperature sensor 1, temperature sensor 2, temperature sensor 3 and temperature sensor 4, and the temperature sensor 1, temperature sensor 2, temperature sensor 3 and temperature sensor 4 are all electrically connected to the main controller.

[0013] Furthermore, the circulation mechanism includes a circulation fan, a solenoid valve and an exhaust valve. One end of the circulation fan is connected to the evaporator, the other end of the circulation fan is connected to one end of the solenoid valve, the other end of the solenoid valve is connected to the test box, and the exhaust valve is fixedly installed on the test box. The circulation fan, solenoid valve and exhaust valve are all electrically connected to the sub-controller.

[0014] Furthermore, the automatic alarm module includes an alarm light and a broadcaster, the alarm light and the broadcaster are fixedly installed on the upper end of the test box, and the alarm light and the broadcaster are electrically connected to the sub-controller.

[0015] Furthermore, the refrigerant detection module includes a refrigerant dosing device, a refrigerant detection device and a drain valve. The refrigerant dosing device is fixedly installed on the evaporator, the refrigerant detection device is fixedly installed inside the evaporator, and the outlet pipe of the evaporator is connected to the drain valve.

[0016] Furthermore, the refrigerant detection device is electrically connected to the main controller.

[0017] Compared with the prior art, the present invention has the following advantages: the main controller of the present invention calculates the temperature difference that needs to be adjusted in the test chamber according to the preset target temperature and the real-time feedback of the high-precision sensor module, and uses the difference as the input signal of the sub-controller; the sub-controller fine-tunes the temperature control actuator according to the input signal and the PID+PWM control algorithm preset in the sub-controller, thereby controlling the flow of refrigerant in the electronic expansion valve, and performing quality detection on the refrigerant in the evaporator through the refrigerant detection module; that is, the system adopts a cascade control structure, and through the coordinated work of the main controller and the sub-controller, it can achieve precise control and stable regulation of the temperature inside the test chamber; at the same time, the system also has real-time monitoring and fault diagnosis functions, which can promptly detect and handle abnormal situations. [Brief Description of the Drawings]

[0018] Figure 1 The connection frame of the utility model Figure 1 ;

[0019] Figure 2 The connection frame of the utility model Figure 2 ;

[0020] In the figure: 1. Main controller; 2. Sub-controller; 3. High-precision sensor module; 31. Temperature sensor 1; 32. Temperature sensor 2; 33. Temperature sensor 3; 34. Temperature sensor 4; 4. Actuator; 41. Compressor; 42. Condenser; 43. Electronic expansion valve; 44. Evaporator; 45. Gas-liquid separator; 5. Circulation mechanism; 51. Circulation fan; 52. Solenoid valve; 53. Exhaust valve; 6. Automatic alarm module; 61. Alarm light; 62. Broadcaster; 7. Refrigerant detection module; 71. Refrigerant dosing device; 72. Refrigerant detection device; 73. Drain valve; 8. Fault diagnosis module. [Specific implementation method]

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0022] Example 1: In some embodiments, please refer to the accompanying drawings of the specification. Figure 1-Figure 2 , a cascade control system for an ultra-low temperature test chamber, comprising a main controller 1 and a sub-controller 2, the main controller 1 and the sub-controller 2 being electrically connected via a communication line, the main controller 1 being connected to a high-precision sensor module 3 for detecting the temperature in the test chamber, and the sub-controller 2 being connected to an actuator 4 for adjusting the temperature in the test chamber;

[0023] The main controller 1 is connected to a refrigerant detection module 7 for refrigerant quality detection and a fault diagnosis module 8 for judging the high-precision sensor module 3, and the sub-controller 2 is connected to an automatic alarm module 6 for alarm reminder;

[0024] The actuator 4 includes a compressor 41, a condenser 42, an electronic expansion valve 43, an evaporator 44 and a gas-liquid separator 45; the outlet pipe of the compressor 41 is connected to the inlet pipe of the condenser 42, the outlet pipe of the condenser 42 is connected to the inlet pipe of the electronic expansion valve 43, the outlet pipe of the electronic expansion valve 43 is connected to the inlet pipe of the evaporator 44, and the outlet pipe of the evaporator 44 is connected to the inlet pipe of the compressor 41 through the gas-liquid separator 45.

[0025] The sub-controller 2 , the compressor 41 , the condenser 42 , the electronic expansion valve 43 , and the evaporator 44 are all electrically connected to the main controller 1 .

[0026] The evaporator 44 is connected to the refrigerant detection module 7 and the circulation mechanism 5 .

[0027] The sub-controller 2 has a built-in PID+PWM control algorithm, where the PID (proportion integration differentiation) algorithm refers to a proportional, integral, and differential control algorithm; and the PWM (Pulse Width Modulation) algorithm refers to a pulse width modulation.

[0028] The main controller 1 calculates the temperature difference that needs to be adjusted within the test chamber based on the preset target temperature and real-time feedback from the high-precision sensor module 3, and uses this difference as the input signal for the sub-controller 2. Based on the input signal and the PID+PWM control algorithm preset by the sub-controller 2, the sub-controller 2 fine-tunes the temperature control actuator 4 to control the refrigerant flow in the electronic expansion valve 43. The refrigerant detection module 7 also performs quality inspections on the refrigerant in the evaporator 44. The system also features real-time monitoring and fault diagnosis capabilities, enabling timely detection and resolution of abnormalities.

[0029] The system adopts a cascade control structure (i.e. the main controller 1 and the sub-controller 2 work in series) to achieve precise control and stable regulation of the internal temperature of the test chamber through the coordinated work of the main controller 1 and the sub-controller 2.

[0030] The high-precision sensor module 3 includes a temperature sensor 1 31 , a temperature sensor 2 32 , a temperature sensor 3 33 and a temperature sensor 4 34 , and the temperature sensor 1 31 , the temperature sensor 2 32 , the temperature sensor 3 33 and the temperature sensor 4 34 are all electrically connected to the main controller 1 .

[0031] The circulation mechanism 5 includes a circulation fan 51, a solenoid valve 52 and an exhaust valve 53. One end of the circulation fan 51 is connected to the evaporator 44, the other end of the circulation fan 51 is connected to one end of the solenoid valve 52, the other end of the solenoid valve 52 is connected to the test box, and the exhaust valve 53 is fixedly installed on the test box. The circulation fan 51, the solenoid valve 52 and the exhaust valve 53 are all electrically connected to the sub-controller 2.

[0032] First, temperature sensor 1 31, temperature sensor 2 32, temperature sensor 3 33, and temperature sensor 4 34 are used to collect the temperatures at different locations in the test chamber and upload them to the main controller 1. The main controller 1 calculates the temperature difference that needs to be adjusted based on the preset target temperature and real-time feedback of the collected temperature, and uses the difference as the input signal of the sub-controller 2.

[0033] The sub-controller 2 controls the compressor 41 to compress the refrigerant into a high-pressure and high-temperature gas, and then cools the high-temperature and high-pressure gas into a liquid state through the condenser 42 .

[0034] Then, the liquid refrigerant passes through the electronic expansion valve 43 and becomes a low-temperature, low-pressure liquid. The sub-controller 2 fine-tunes the electronic expansion valve 43 according to the input signal and the preset PID+PWM control algorithm, thereby controlling the flow of refrigerant entering the evaporator 44.

[0035] The refrigerant enters the evaporator 44, and the sub-controller 2 controls the circulation fan 51 to start, and the solenoid valve 52 is opened. The circulation fan 51 draws the gas inside the test box into the evaporator 44 for cooling, and then discharges it into the test box;

[0036] In the evaporator 44, the low-temperature, low-pressure liquid refrigerant absorbs the heat in the test chamber, and then turns into gas and is sucked into the compressor 41 again through the gas-liquid separator 45. This cycle can reduce the temperature in the chamber, thereby achieving temperature regulation of the test chamber.

[0037] In addition, in order to maintain the ultra-low temperature environment inside the test chamber, the test chamber will also be insulated with thermal insulation materials with extremely strong thermal insulation properties.

[0038] Embodiment 2: In some embodiments, as Figure 2 As shown, as a preferred embodiment of the present invention, the automatic alarm module 6 includes an alarm light 61 and a broadcaster 62, and the alarm light 61 and the broadcaster 62 are fixedly installed at the upper end of the test box, and the alarm light 61 and the broadcaster 62 are electrically connected to the sub-controller 2.

[0039] The main controller 1 calculates the temperature difference that needs to be adjusted based on the temperatures collected by temperature sensor 1 31, temperature sensor 2 32, temperature sensor 3 33, and temperature sensor 4 34, and uses the difference as the input signal of the sub-controller 2. The sub-controller 2 controls the opening of the evaporator 44 and the circulation fan 51 according to the signal of the main controller 1 to adjust the temperature of the test chamber;

[0040] However, after the temperature of the test chamber is adjusted, the temperatures collected by temperature sensor 1 31, temperature sensor 2 32, temperature sensor 3 33, and temperature sensor 4 34 received by the main controller 1 do not change. The fault diagnosis module 8 determines that a device in the system has failed. The main controller 1 sends the fault information to the sub-controller 2. The sub-controller 2 controls the alarm light 61 and the broadcaster 62 to sound an alarm. The alarm light 61 and the broadcaster 62 warn the on-site staff to investigate the cause of the fault.

[0041] The refrigerant detection module 7 includes a refrigerant dosing device 71, a refrigerant detection device 72 and a drain valve 73. The refrigerant dosing device 71 is fixedly installed on the evaporator 44, the refrigerant detection device 72 is fixedly installed inside the evaporator 44, and the outlet pipe of the evaporator 44 is connected to the drain valve 73.

[0042] The refrigerant dosing device 71 adopts an air conditioning refrigerant dosing device disclosed in patent CN210602375U.

[0043] The refrigerant detection device 72 is electrically connected to the main controller 1 .

[0044] The refrigerant detection device 72 adopts existing mature technology, and the refrigerant detection device 72 adopts a refrigerant identification instrument.

[0045] When the present invention is in use, the refrigerant detection device 72 detects the concentration of the refrigerant in the evaporator 44 and uploads it to the main controller 1. If the main controller 1 detects that the concentration of the refrigerant is lower than the concentration set in the main controller 1, the main controller 1 controls the drain valve 73 to open, and discharges the refrigerant in the evaporator 44 to the recovery device. The staff re-adds refrigerant to the evaporator 44 through the refrigerant dosing device 71, thereby realizing real-time monitoring of the refrigerant concentration and preventing refrigerant problems from affecting the temperature control of the test chamber.

[0046] The contents not described in detail in this specification belong to the existing technology known to professional and technical personnel in this field. The standard parts used can be purchased from the market, and special-shaped parts can be customized according to the description in the specification and drawings. The specific connection methods of each part adopt mature conventional means such as bolts, rivets, welding, etc. in the existing technology. The machinery, parts and equipment all adopt conventional models in the existing technology, and the circuit connections adopt conventional connection methods in the existing technology, which will not be described in detail here.

[0047] The present invention is not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A cascade control system for an ultra-low temperature test chamber, characterized in that: The invention comprises a main controller (1) and a sub-controller (2), wherein the main controller (1) and the sub-controller (2) are electrically connected via a communication line, the main controller (1) is connected to a high-precision sensor module (3) for detecting the temperature in the test chamber, and the sub-controller (2) is connected to an actuator (4) for adjusting the temperature in the test chamber; The main controller (1) is connected to a refrigerant detection module (7) for detecting refrigerant quality and a fault diagnosis module (8) for judging the high-precision sensor module (3), and the sub-controller (2) is connected to an automatic alarm module (6) for alarm reminder; The actuator (4) comprises a compressor (41), a condenser (42), an electronic expansion valve (43), an evaporator (44) and a gas-liquid separator (45); the outlet pipe of the compressor (41) is connected to the inlet pipe of the condenser (42), the outlet pipe of the condenser (42) is connected to the inlet pipe of the electronic expansion valve (43), the outlet pipe of the electronic expansion valve (43) is connected to the inlet pipe of the evaporator (44), and the outlet pipe of the evaporator (44) is connected to the inlet pipe of the compressor (41) through the gas-liquid separator (45).

2. The ultra-low temperature test chamber cascade control system according to claim 1, characterized in that: The auxiliary controller (2), the compressor (41), the condenser (42), the electronic expansion valve (43), and the evaporator (44) are all electrically connected to the main controller (1).

3. The ultra-low temperature test chamber cascade control system according to claim 2, characterized in that: The evaporator (44) is connected to the refrigerant detection module (7) and the circulation mechanism (5).

4. The ultra-low temperature test chamber cascade control system according to claim 3, characterized in that: The high-precision sensor module (3) comprises a temperature sensor 1 (31), a temperature sensor 2 (32), a temperature sensor 3 (33) and a temperature sensor 4 (34), and the temperature sensor 1 (31), the temperature sensor 2 (32), the temperature sensor 3 (33) and the temperature sensor 4 (34) are all electrically connected to the main controller (1).

5. The ultra-low temperature test chamber cascade control system according to claim 4, characterized in that: The circulation mechanism (5) comprises a circulation fan (51), a solenoid valve (52) and an exhaust valve (53); one end of the circulation fan (51) is communicated with the evaporator (44); the other end of the circulation fan (51) is connected to one end of the solenoid valve (52); the other end of the solenoid valve (52) is connected to the test box; the exhaust valve (53) is fixedly mounted on the test box; the circulation fan (51), the solenoid valve (52) and the exhaust valve (53) are all electrically connected to the sub-controller (2).

6. The ultra-low temperature test chamber cascade control system according to claim 5, characterized in that: The automatic alarm module (6) comprises an alarm light (61) and a broadcaster (62), wherein the alarm light (61) and the broadcaster (62) are fixedly mounted on the upper end of the test box, and the alarm light (61) and the broadcaster (62) are both electrically connected to the sub-controller (2).

7. The ultra-low temperature test chamber cascade control system according to claim 6, characterized in that: The refrigerant detection module (7) comprises a refrigerant dosing device (71), a refrigerant detection device (72) and a drain valve (73); the refrigerant dosing device (71) is fixedly mounted on the evaporator (44); the refrigerant detection device (72) is fixedly mounted inside the evaporator (44); and the outlet pipe of the evaporator (44) is connected to the drain valve (73).

8. The ultra-low temperature test chamber cascade control system according to claim 7, characterized in that: The refrigerant detection device (72) is electrically connected to the main controller (1).

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