System and method for judging blow-by fault

Abstract

The invention discloses a blow-by fault judgment system and method, and the system comprises a power supply which supplies power to a compressor; the compressor generates high-pressure gas and recovers low-pressure gas; the motor drives the refrigerator to operate; the high-pressure gas pipeline is used for supplying high-pressure gas generated by the compressor to the refrigerating machine A and the to-be-detected equipment B; the low-pressure gas pipeline is used for returning expanded gas of the refrigerating machine A and the to-be-detected equipment B to the compressor; the valve is used for closing or opening a high-pressure and low-pressure gas loop of the to-be-detected equipment B; the refrigerator A comprises a rotary valve and an air distribution valve; the temperature sensor is used for collecting the temperature of the refrigerator A, the data acquisition instrument is used for collecting temperature data collected by the temperature sensor, and whether the to-be-detected equipment B has a blow-by fault or not is judged by monitoring the temperature change of the refrigerator A. The blow-by fault judgment system is simple, and the method is efficient and easy to implement.

Description

Technical Field

[0001] This invention belongs to the field of cryogenic technology and relates to a system and method for determining gas leakage faults. Background Technology

[0002] Equipment gas leakage faults are difficult to detect due to their high degree of concealment, complex location and diagnosis, and numerous interfering factors. Taking the GM refrigerator as an example, as a type of valve-controlled refrigerator, the GM refrigerator controls the switching of high and low pressure gas circuits through valves to achieve a continuous Simon expansion refrigeration process. In this process, the regenerator in the refrigerator gradually accumulates cold energy during the continuous Simon expansion, and then outputs the generated cold energy to the object being cooled through the cold end heat exchanger. This refrigeration method is safe, stable, and has a long service life, with a wide range of applications, such as zero-evaporation MRI systems, helium purification and liquefaction systems, and CPMS high-precision measuring instruments that use GM refrigerators.

[0003] The safety and stability of GM refrigerators in use have been proven in practice. However, during the assembly of GM refrigerators, there is still a problem of low first-pass yield, requiring rework. When faced with GM refrigerators that need rework, it is first necessary to determine the cause of the malfunction in order to troubleshoot the problem and improve production efficiency. However, GM refrigerators have a complex structure and are prone to many problems. For example, if the rotary valve and the gas distribution valve are not tightly matched, it can cause gas leakage in the GM refrigerator. This means that some high-pressure gas flows directly into the low-pressure pipeline circuit without passing through the regenerator and cylinder, and does not participate in the expansion and refrigeration process. At the same time, as high-pressure gas enters, the pressure in the low-pressure circuit rises, which also causes the expansion efficiency of the high-pressure gas in the cylinder to decrease when expanding into the low-pressure circuit. Ultimately, under the combined influence of the above two factors, the cooling capacity of the refrigerator decreases significantly. Summary of the Invention

[0004] Purpose of the invention: The present invention aims to quickly determine whether a faulty device is experiencing a gas leakage fault, and provides a gas leakage fault determination system and method.

[0005] Technical solution: The present invention provides a gas leakage fault detection system, comprising: a power supply, a compressor, a motor, a high-pressure gas pipeline, a low-pressure gas pipeline, valves, a data acquisition instrument, a temperature sensor, a refrigeration unit A, and at least one device B to be tested to detect whether a gas leakage fault exists; wherein, The power source is used to power the compressor; The compressor is used to generate high-pressure gas and recover low-pressure gas. The motor is used to drive the refrigeration unit A. The high-pressure gas pipeline is used to supply the high-pressure gas generated by the compressor to the refrigerator A and the device under test B; the low-pressure gas pipeline is used to return the expanded gas from the refrigerator A and the device under test B to the compressor; the high-pressure gas pipelines of the refrigerator A and the device under test B are connected in parallel to the high-pressure side of the compressor, and the low-pressure gas pipelines of the refrigerator A and the device under test are connected in parallel to the low-pressure side of the compressor. The valve is used to close or open the high-pressure and low-pressure gas circuits of the device B to be tested. The refrigeration unit A includes a rotary valve, a gas distribution valve, and a regenerator. The gas distribution valve and the rotary valve are tightly fitted together. High-pressure gas first enters the regenerator from the high-pressure gas pipeline, and then expands from the regenerator to the low-pressure gas pipeline, thereby completing a refrigeration cycle. The temperature sensor is used to collect the temperature of the refrigerator A, and the data acquisition instrument is used to collect the temperature data collected by the temperature sensor. By monitoring the temperature change of the refrigerator A, it is possible to determine whether there is a gas leakage fault in the device B under test.

[0006] Furthermore, the temperature sensor includes a primary temperature sensor and a secondary temperature sensor, which are used to collect the primary and secondary temperatures of the refrigerator A, respectively.

[0007] Furthermore, the device to be tested, B, is one unit; the high-pressure gas pipeline includes a high-pressure inlet main line, a high-pressure inlet A line, and a high-pressure inlet B line; the low-pressure gas pipeline includes a low-pressure return gas main line, a low-pressure return gas A line, and a low-pressure return gas B line; the high-pressure inlet A line and the high-pressure inlet B line are connected in parallel to the high-pressure inlet main line; and the low-pressure return gas A line and the low-pressure return gas B line are connected in parallel to the low-pressure return gas main line.

[0008] Furthermore, the valve includes a high-pressure valve and a low-pressure valve, with the high-pressure valve located at the high-pressure air inlet B path and the low-pressure valve located at the low-pressure air return B path.

[0009] Furthermore, the device B to be tested is a GM refrigerator, a GM-type pulse tube refrigerator, or other devices that may have gas leakage faults.

[0010] Another aspect of the present invention is to provide a method for determining gas leakage faults using the above-described system, comprising the following steps: S1. Close the valve and start the refrigeration unit A; S2. After the temperature of the refrigeration unit A stabilizes, connect the device B to be tested and open the valve; S3. Determine if there is a temperature fluctuation in refrigeration unit A. If so, determine that the device B under test has a gas leakage fault. S4. If not, then the device B under test does not have a gas leakage fault; S5. Close the valve and remove the device B to be tested.

[0011] Furthermore, step S1 is the initial operation start point, and step S2 is the normal operation start point. The refrigeration unit A maintains normal operation in step S2. Subsequently, it is only necessary to connect the device B to be tested to the gas leakage fault determination system to quickly determine whether the device B to be tested has a gas leakage fault.

[0012] Beneficial effects: (1) This invention provides a fast, indirect and efficient gas leakage fault determination system and method, which diagnoses whether the equipment under test has gas leakage fault by monitoring the performance degradation of a normally operating refrigeration unit, without the need for complex disassembly of the equipment under test or reliance on expensive special testing equipment. (2) By real-time monitoring of the first and second temperature changes of normal refrigeration unit A before and after the device under test is connected, the present invention can quickly obtain diagnostic signals. This method avoids the time-consuming process of traditional shutdown and pressure holding tests, and greatly shortens the fault determination time. (3) The system of the present invention is simple, low in cost and easy to implement. It mainly relies on existing refrigeration infrastructure and only requires the addition of valves to isolate faulty machines, as well as temperature sensors and data acquisition instruments to monitor performance changes, thus reducing costs. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the working state of the rotary valve and the air distribution valve under normal conditions, where (a) is the high-pressure air intake stage and (b) is the low-pressure air return stage.

[0014] Figure 2 This is a schematic diagram of the working state of the rotary valve and the distribution valve under the fault of gas leakage, where (a) is the high pressure intake stage and (b) is the low pressure return stage.

[0015] Figure 3 This is a schematic diagram of a gas leakage fault detection system according to one embodiment of the present invention.

[0016] Figure 4 This is a flowchart of a method for determining gas leakage faults according to the present invention.

[0017] In the diagram: 20 - Gas leakage fault detection system; 1 - Power supply; 2 - Compressor; 3, 4 - Motor; 5 - High-pressure air intake main circuit; 51 - High-pressure air intake A circuit; 52 - High-pressure air intake B circuit; 6 - Low-pressure air return main circuit; 61 - Low-pressure air return A circuit; 62 - Low-pressure air return B circuit; 71 - High-pressure valve; 72 - Low-pressure valve; 8 - Data acquisition instrument; 91 - Primary temperature sensor; 92 - Secondary temperature sensor; A - Refrigeration unit A; B - Device under test B; 10 - Rotary valve; 11 - Gas distribution valve; 12 - Gap space; 13 - Regenerator. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0019] Figure 1 This diagram illustrates the operating state of the gas distribution valve 11 and rotary valve 10 under normal conditions. The structure mainly consists of rotary valve 10, gas distribution valve 11, high-pressure inlet A-path 51, low-pressure return A-path 61, and regenerator 13. Under normal conditions, during the high-pressure inlet and low-pressure return phases, gas distribution valve 11 and rotary valve 10 are tightly closed. High-pressure gas first enters the regenerator 13 from high-pressure inlet A-path 51, and then expands from the regenerator 13 to low-pressure return A-path 61, thus completing one refrigeration cycle.

[0020] Figure 2 This illustration shows the operating states of the gas distribution valve 11 and rotary valve 10 in the event of a gas leakage fault in the refrigeration unit. The structures involved, in addition to those described above... Figure 1 The structure also includes a high-pressure intake B-channel 52, a low-pressure return B-channel 62, and a gap space 12. The gap space 12 is located between the distribution valve 11 and the rotary valve 10. In this configuration, some of the high-pressure gas in the high-pressure intake B-channel 52 does not enter the regenerator 13 but instead directly enters the low-pressure return B-channel 62 through the gap space 12. This results in insufficient gas entering the regenerator 13, thus affecting the cooling capacity of the refrigerator. Furthermore, as the high-pressure gas directly enters the low-pressure return B-channel 62, the pressure in the low-pressure return B-channel 62 increases. This causes a decrease in gas expansion efficiency when the high-pressure gas in the regenerator 13 expands into the low-pressure return B-channel 62, further reducing the cooling capacity of the refrigerator.

[0021] like Figure 3 As shown, the gas leakage fault determination system of this embodiment includes: a power supply 1, a compressor 2, a motor 3, a high-pressure gas pipeline, a low-pressure gas pipeline, valves, a data acquisition instrument 8, a temperature sensor, a refrigerator A, and at least one device B to be tested for gas leakage faults. The power supply 1 supplies power to the compressor 2; the compressor 2 generates high-pressure gas and recovers low-pressure gas; the motor 3 drives the refrigerator A; the high-pressure gas pipeline supplies the high-pressure gas generated by the compressor 2 to the refrigerator A and the device B to be tested; the low-pressure gas pipeline returns the expanded gas from the refrigerator A and the device B to the compressor 2; the high-pressure gas pipelines of the refrigerator A and the device B to be tested are connected in parallel to the high-pressure side of the compressor 2, and the low-pressure gas pipelines of the refrigerator A and the device B to be tested are connected in parallel to the low-pressure side of the compressor 2; the valves are used to close or open the high-pressure and low-pressure gas circuits of the device B to be tested; the temperature sensor collects the temperature of the refrigerator A, and the data acquisition instrument 8 collects the temperature data collected by the temperature sensor. By monitoring the temperature change of the refrigerator A, the system determines whether the device B to be tested has a gas leakage fault.

[0022] In the specific implementation process, the device to be tested, B, can be one or more. The device to be tested, B, can be a GM refrigerator, a GM-type pulse tube refrigerator, or other devices that may have gas leakage faults. These devices to be tested are connected in parallel with the refrigerator A.

[0023] In one specific implementation, the device to be tested, B, is a single unit and is also a refrigeration unit, defined as refrigeration unit B. In this embodiment, the gas leakage fault determination system 20 includes a power supply 1, a compressor 2, a motor 3, a motor 4, a high-pressure air intake main 5, a high-pressure air intake A duct 51, a high-pressure air intake B duct 52, a low-pressure return air main 6, a low-pressure return air A duct 61, a low-pressure return air B duct 62, a high-pressure valve 71, a low-pressure valve 72, a data acquisition instrument 8, a primary temperature sensor 91, a secondary temperature sensor 92, refrigeration unit A, and refrigeration unit B. Power supply 1 supplies power to compressor 2, ensuring its normal operation; compressor 2 provides high-pressure gas and recovers low-pressure gas after expansion to the gas leakage fault detection system 20; motor 3 drives refrigeration unit A; high-pressure intake main 5 and low-pressure return main 6 provide high-pressure gas and recover low-pressure gas after expansion to the gas leakage fault detection system 20, respectively; high-pressure valve 71 and low-pressure valve 72 open or close the refrigeration unit B circuit; data acquisition instrument 8 records and saves the primary and secondary temperature values ​​of refrigeration unit A collected by primary temperature sensor 91 and secondary temperature sensor 92, to determine whether refrigeration unit A has reached a stable state.

[0024] Combination Figure 4 As shown, the determination method using the gas leakage fault determination system 20 is explained.

[0025] After connecting the normally functioning refrigerator A and the refrigerator B to be tested to their respective positions, close the high-pressure valve 71 and the low-pressure valve 72, and then turn on the power supply 1. The compressor 2, after being powered on, immediately begins to drive refrigerator A. At this time, due to the closure of the high-pressure valve 71 and the low-pressure valve 72, refrigerator B is not actually connected to the gas circulation of the gas leakage fault determination system 20. That is, any state of refrigerator B will not affect the normal operation of refrigerator A. At this time, the data acquisition instrument 8 will collect the primary and secondary temperature data of refrigerator A during operation through the primary temperature sensor 91 and the secondary temperature sensor 92. Then, based on the trend of the primary and secondary temperature values ​​of refrigerator A, it will determine whether refrigerator A has reached a stable state.

[0026] When the temperature data of the first and second stages of the refrigerator A collected by the data acquisition instrument 8 continue to change within a certain range, it indicates that the refrigerator A has reached a stable state.

[0027] After the primary and secondary temperatures of refrigeration unit A stabilize, simultaneously open high-pressure valve 71 and low-pressure valve 72 to connect refrigeration unit B to the cross-flow fault detection system 20. At this time, if refrigeration unit B does not have a cross-flow fault, meaning that rotary valve 10 and distribution valve 11 are in a tightly coordinated normal operating state, such as... Figure 1 As shown, since the refrigerator B is not powered on, the rotary valve 10 and the gas distribution valve 11 in the refrigerator B will not move relative to each other, that is, there will be no switching between the high and low pressure gas circuits. At this time, the refrigerator B plays the same role as the high pressure valve 71 and the low pressure valve 72, blocking the connection between the high pressure intake B line 52 and the low pressure return B line 62 of the refrigerator B side loop. That is, the refrigerator B is connected to the cross-flow fault judgment system 20. The pressure in the high pressure intake A line 51 and the low pressure return A line 61 at both ends of the refrigerator A will not change. That is, the refrigerator B will not affect the operation of the refrigerator A. The primary and secondary temperatures of the refrigerator A will remain stable within the previous fluctuation range.

[0028] Conversely, if the refrigeration unit B has a cross-flow fault, that is, the rotary valve 10 and the gas distribution valve 11 exhibit... Figure 2 The operating state is such that the rotary valve 10 and the gas distribution valve 11 are not tightly fitted, and there is a gap space 12 between them. When the high-pressure valve 71 and the low-pressure valve 72 are opened, although the refrigerator B is not powered on, the rotary valve 10 and the gas distribution valve 11 will not move relative to each other, that is, there is no switching between the high-pressure and low-pressure gas circuits; however, due to the existence of the gap space 12, some of the high-pressure gas in the high-pressure intake B passage 52 can still directly enter the low-pressure return B passage 62, the low-pressure return A passage 61, and the low-pressure return main passage 6 through the gap space 12. This will result in a reduction in the amount of high-pressure gas entering the refrigerator A through the high-pressure intake A passage 51, causing fluctuations in the refrigeration temperature of the refrigerator A; on the other hand, as the high-pressure gas in the high-pressure intake B passage 52 enters the low-pressure return A passage 61, the pressure in the low-pressure return A passage 61 will rise accordingly. Therefore, when the refrigerator A expands into the low-pressure return A passage 61, the expansion efficiency of the refrigerator A will decrease, which will further lead to greater temperature fluctuations in the refrigerator A. The above analysis shows that when the refrigeration unit B with the gas leakage fault is connected to the gas leakage fault determination system 20, the refrigeration unit B will affect the operation of the refrigeration unit A, and cause the primary and secondary temperatures of the refrigeration unit A to be unstable within the previous normal range.

[0029] Table 1 shows the measured performance changes of refrigerator A when a certain refrigerator B with a gas leakage fault is connected to the fault determination system 20. Subsequently, valves 71 and 72 are closed, refrigerator B is removed from the gas leakage fault determination system 20, and gas leakage fault handling is performed. After the handling is completed, the above steps are repeated.

[0030] Table 1: The impact of a certain gas leakage fault in refrigerator B on the performance of refrigerator A

[0031] As can be seen from Table 1, when a faulty chiller B is connected, it has a significant negative impact on the primary and secondary refrigeration performance of the normal chiller A, causing its operating temperature to rise under the same load.

[0032] The above is the procedure that the cross-flow fault determination system 20 needs to perform when it is first run. After the cross-flow fault determination system 20 is running, the refrigerator A will continue to operate normally. Subsequently, it is only necessary to connect the refrigerator B to be tested to the cross-flow fault determination system 20 to quickly determine whether the refrigerator B to be tested has a cross-flow fault.

[0033] As explained above, the gas leakage fault determination system 20 according to the embodiment can effectively determine whether the refrigeration unit B has a gas leakage fault, thereby improving the speed of eliminating gas leakage faults in the refrigeration unit and increasing the production speed of the refrigeration unit.

[0034] This invention is not limited to the above-described embodiments. Those skilled in the art will understand that various design changes can be implemented and various modifications can exist, and such modifications are also included within the scope of this invention.

Claims

1. A gas leakage fault detection system, characterized in that, include: The system includes a power supply, compressor, motor, high-pressure gas pipeline, low-pressure gas pipeline, valves, data acquisition instrument, temperature sensor, refrigeration unit A, and at least one device B to be tested for potential gas leakage faults; among which, The power source is used to power the compressor; The compressor is used to generate high-pressure gas and recover low-pressure gas. The motor is used to drive the refrigeration unit A. The high-pressure gas pipeline is used to supply the high-pressure gas generated by the compressor to the refrigerator A and the device under test B; the low-pressure gas pipeline is used to return the expanded gas from the refrigerator A and the device under test B to the compressor; the high-pressure gas pipelines of the refrigerator A and the device under test B are connected in parallel to the high-pressure side of the compressor, and the low-pressure gas pipelines of the refrigerator A and the device under test are connected in parallel to the low-pressure side of the compressor. The valve is used to close or open the high-pressure and low-pressure gas circuits of the device B to be tested. The refrigeration unit A includes a rotary valve, a gas distribution valve, and a regenerator. The gas distribution valve and the rotary valve are tightly fitted together. High-pressure gas first enters the regenerator from the high-pressure gas pipeline, and then expands from the regenerator to the low-pressure gas pipeline, thereby completing a refrigeration cycle. The temperature sensor is used to collect the temperature of the refrigerator A, and the data acquisition instrument is used to collect the temperature data collected by the temperature sensor. By monitoring the temperature change of the refrigerator A, it is possible to determine whether there is a gas leakage fault in the device B under test.

2. The gas leakage fault determination system according to claim 1, characterized in that, The temperature sensor includes a primary temperature sensor and a secondary temperature sensor, which are used to collect the primary and secondary temperatures of the refrigeration unit A, respectively.

3. The gas leakage fault determination system according to claim 1, characterized in that, The device to be tested, B, is one unit. The high-pressure gas pipeline includes a high-pressure inlet main line, a high-pressure inlet A line, and a high-pressure inlet B line. The low-pressure gas pipeline includes a low-pressure return gas main line, a low-pressure return gas A line, and a low-pressure return gas B line. The high-pressure inlet A line and the high-pressure inlet B line are connected in parallel to the high-pressure inlet main line, and the low-pressure return gas A line and the low-pressure return gas B line are connected in parallel to the low-pressure return gas main line.

4. The gas leakage fault determination system according to claim 3, characterized in that, The valve includes a high-pressure valve and a low-pressure valve. The high-pressure valve is located at the high-pressure air inlet B, and the low-pressure valve is located at the low-pressure air return B.

5. The gas leakage fault determination system according to claim 1, characterized in that, The device B to be tested is a GM refrigerator, a GM-type pulse tube refrigerator, or other devices that may have gas leakage faults.

6. A method for determining gas leakage faults using the system described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Close the valve and start the refrigeration unit A; S2. After the temperature of the refrigeration unit A stabilizes, connect the device B to be tested and open the valve; S3. Determine if there is a temperature fluctuation in refrigeration unit A. If so, determine that the device B under test has a gas leakage fault. S4. If not, then the device B under test does not have a gas leakage fault; S5. Close the valve and remove the device B to be tested.

7. The method for determining gas leakage faults according to claim 6, characterized in that, Step S1 is the initial start point for operation, and step S2 is the normal operation start point. The refrigeration unit A maintains normal operation in step S2. Subsequently, it is only necessary to connect the device B to be tested to the gas leakage fault determination system to quickly determine whether the device B to be tested has a gas leakage fault.

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