Test system for simulating and detecting refrigerant leakage

Abstract

The utility model provides a test system for simulating and detecting refrigerant leakage, which comprises a water pipeline simulation system in a heat pump unit. The heat pump unit inner water pipeline simulation system comprises a first check valve, a refrigerant leakage detection device in pipeline connection with the water outlet end of the first check valve, an exhaust tank connected with the water outlet end of the refrigerant leakage detection device and an electric stop valve connected with the water outlet end of the exhaust tank, and the refrigerant leakage detection device is electrically connected with the input end of the controller. The output end of the controller is electrically connected with the electric stop valve, a first safety assembly is installed at an exhaust port of the exhaust tank, an air inlet is formed in a pipeline between the first check valve and the refrigerant leakage detection device, and the gas filling system is connected with the water pipeline simulation system in the heat pump unit through the air inlet. According to the utility model, the refrigerant pressure and the leakage speed of the heat pump unit in different operation conditions can be simulated truly, the response time and the control function of the detection device can be verified effectively, the safety is high, and the time and the cost are saved.

Description

Technical Field

[0001] This utility model belongs to the field of air conditioning heat pump operation detection technology, and in particular relates to a test system for simulating and detecting refrigerant leakage. Background Technology

[0002] With the advancement of refrigerant substitution programs both domestically and internationally, flammable refrigerants such as R290 and R32 are increasingly widely used in air conditioning heat pump units due to their excellent environmental performance. However, the flammability of these refrigerants poses significant safety risks. Taking an air conditioning heat pump unit as an example, the refrigerant cools or heats water or other media within the heat exchanger, and the resulting chilled (hot) water is sent to the user-side terminals, such as fan coil units or underfloor heating, to achieve cooling and heating. However, when the heat exchanger, such as a plate heat exchanger, experiences internal leakage due to mechanical vibration or icing, the refrigerant in the refrigerant system can enter the water system from the leak point and then flow with the water system to the user-side terminals, creating a safety hazard. Therefore, detecting leaks of flammable refrigerants and implementing timely system protection when leaks occur is an urgent problem to be solved. However, directly using the heat pump unit for testing poses certain safety risks and is costly. Based on the above, this utility model provides a testing system for simulating and detecting refrigerant leaks to solve the aforementioned problems. Summary of the Invention

[0003] The problem this invention aims to solve is to provide a test system that can realistically simulate refrigerant pressure and leakage rate when a heat pump unit leaks under different operating conditions, effectively verify the response time and control effectiveness of the detection device, and is highly safe and low-cost for simulating and detecting refrigerant leaks.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a test system for simulating and detecting refrigerant leakage, comprising:

[0005] A water pipeline simulation system for heat pump units is used to simulate the operating conditions of water pipelines within heat pump units.

[0006] An external water pipeline simulation system is connected between the inlet and outlet of the internal water pipeline simulation system of the heat pump unit, and is used to simulate the operating conditions of the external water pipeline of the heat pump unit.

[0007] The gas charging system is connected to the water pipeline simulation system inside the heat pump unit to simulate refrigerant leakage conditions.

[0008] The heat pump unit's internal water pipeline simulation system includes a first check valve, a refrigerant leak detection device connected to the outlet pipe of the first check valve, an exhaust tank connected to the outlet pipe of the refrigerant leak detection device, and an electric shut-off valve connected to the outlet pipe of the exhaust tank. The refrigerant leak detection device is electrically connected to the input of a controller, and the output of the controller is electrically connected to the electric shut-off valve. A first safety component is installed at the exhaust port of the exhaust tank via a second shut-off valve. An air inlet is provided on the pipeline between the first check valve and the refrigerant leak detection device. The gas filling system is connected to the heat pump unit's internal water pipeline simulation system through the air inlet.

[0009] Furthermore, the gas filling system includes a gas cylinder, and a pressure reducing valve, a second check valve, a fine-tuning valve and a first shut-off valve are sequentially connected to the valve port of the gas cylinder, with the outlet of the first shut-off valve connected to the inlet pipe.

[0010] Furthermore, the external water pipeline simulation system includes an inlet pipeline, the inlet end of which is connected to a booster pump, and the outlet end of which is connected to a first branch and a second branch respectively. The other end of the first branch is connected to the outlet of an electric shut-off valve. A third shut-off valve is installed on the pipeline of the first branch, and a second safety component is installed at the outlet of the third shut-off valve. The other end of the second branch is connected to the inlet of a first check valve. A manual regulating valve, a water pump, a flow meter, and an expansion tank are installed sequentially along the water flow direction on the second branch.

[0011] Furthermore, both the first and second safety components include a safety valve, an automatic vent valve, and a pressure gauge installed in parallel.

[0012] Furthermore, an electric heater is installed on the second branch between the manual regulating valve and the water pump.

[0013] Furthermore, pressure taps are provided on both sides of the first check valve and the refrigerant leakage detection device, and the pressure taps on both sides are connected to the differential pressure sensor through conduits.

[0014] Compared with the prior art, the advantages and beneficial effects of this utility model are:

[0015] 1. Since the refrigerant pressure in a heat pump unit is related to the type of heat exchanger and the specific operating conditions, this utility model uses a pressure reducing valve and a fine-tuning valve in the gas charging system to adjust the gas pressure and flow rate, thereby simulating different refrigerant pressures and leakage rates during actual leaks. Simultaneously, after the refrigerant enters the water pipeline simulation system within the heat pump unit, the refrigerant leak detection device detects an abnormal signal and transmits it to the controller. The controller then controls the electric shut-off valve to close. After the electric shut-off valve closes, it works in conjunction with the first check valve, effectively cutting off the unit's water system from the user's water pipeline after an actual leak. Simultaneously, the response time of the refrigerant leak detection device under simulated operating conditions can be recorded, and the control functions of key components can be verified. Compared to testing with an actual heat pump unit, this method offers higher safety and saves costs.

[0016] 2. In the heat pump unit internal water pipeline simulation system of this utility model, the gas entering during the refrigerant gas filling process will be stored in the exhaust tank. When the gas filling amount is large or the gas filling time is long, the volume of the exhaust tank is insufficient to hold all the gas. Then the second shut-off valve is opened, so that the gas entering the exhaust tank is discharged from the automatic exhaust valve in the first safety component. This effectively prevents the gas from flowing through the exhaust tank and entering the downstream components, causing the added refrigerant gas to circulate twice in the refrigerant leak detection device, which would affect the test accuracy. Attached Figure Description

[0017] Figure 1 This is a system flowchart of a test system for simulating and detecting refrigerant leakage according to a first embodiment of the present invention.

[0018] Figure 2 This is a system flowchart of Embodiment 2 of the test system for simulating and detecting refrigerant leakage according to this utility model.

[0019] In the diagram: 1-Simulation system of internal water pipeline of heat pump unit; 2-Simulation system of external water pipeline; 3-Gas filling system; 4-First check valve; 5-Refrigerant leak detection device; 6-Exhaust tank; 7-Electric shut-off valve; 8-Controller; 9-Air inlet; 10-Gas cylinder; 11-Pressure reducing valve; 12-Second check valve; 13-Fine adjustment valve; 14-First shut-off valve; 15-Water inlet pipeline; 16-First branch; 17-Second branch; 18-Manual regulating valve; 19-Water pump; 20-Flow meter; 21-Expansion tank; 22-Second shut-off valve; 23-Safety valve; 24-Automatic exhaust valve; 25-Pressure gauge; 26-Electric heater; 27-Pressure tap; 28-Conduit; 29-Differential pressure sensor; 30-Third shut-off valve; 31-Pressure pump. Detailed Implementation

[0020] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0021] Example 1

[0022] like Figure 1 As shown, a test system for simulating and detecting refrigerant leaks includes:

[0023] A water pipeline simulation system 1 for heat pump units is used to simulate the operating conditions of water pipelines within heat pump units. The water pipeline simulation system 1 includes a first check valve 4, a refrigerant leak detection device 5 connected to the outlet pipe of the first check valve 4, an exhaust tank 6 connected to the outlet pipe of the refrigerant leak detection device 5, and an electric shut-off valve 7 connected to the outlet pipe of the exhaust tank 6. The refrigerant leak detection device 5 is electrically connected to the input of a controller 8, and the output of the controller 8 is electrically connected to the electric shut-off valve 7. A first safety component is installed at the exhaust port of the exhaust tank 6 through a second shut-off valve 22. An air inlet 9 is provided on the pipeline between the first check valve 4 and the refrigerant leak detection device 5.

[0024] Specifically, in the heat pump unit's internal water pipeline simulation system 1, when refrigerant gas is being added through the inlet 9, and the gas flows through the refrigerant leak detection device 5 with the water flow, the detection device outputs an abnormal signal to the controller 8. The controller 8 outputs a feedback signal to perform a protective action, closing the electric shut-off valve 7. After the electric shut-off valve 7 closes, it cooperates with the first check valve 4, which is equivalent to cutting off the unit's water system from the user's water pipeline after an actual leak. At the same time, it can record the response time of the refrigerant leak detection device 5 under simulated operating conditions and verify the control functions of key components. Compared with testing with an actual heat pump unit, it is safer and saves costs.

[0025] The exhaust tank 6 is used to store the injected gas. A level gauge can be installed on the exhaust tank 6 to indicate the amount of injected gas. After the refrigerant gas passes through the refrigerant leak detection device 5, it is stored in the exhaust tank. When the gas filling amount is large or the filling time is long, the volume of the exhaust tank is insufficient to hold all the gas. Then the second shut-off valve is opened, allowing the gas entering the exhaust tank to be discharged from the automatic exhaust valve in the first safety component. This effectively prevents the gas from flowing through the exhaust tank and entering the downstream components, causing the added refrigerant gas to circulate twice in the refrigerant leak detection device, which would affect the test accuracy.

[0026] The gas filling system 3 is connected to the water pipeline simulation system 1 in the heat pump unit to simulate refrigerant leakage conditions. The gas filling system 3 includes a gas cylinder 10. A pressure reducing valve 11, a second check valve 12, a fine-tuning valve 13 and a first shut-off valve 14 are connected in sequence at the valve port of the gas cylinder 10. The outlet of the first shut-off valve 14 is connected to the gas inlet 9.

[0027] Specifically, nitrogen can be filled into the gas cylinder 10 to simulate refrigerant gas. In the gas filling system 3, the gas pressure and flow rate are adjusted by the pressure reducing valve 11 and the fine-tuning valve 13 to simulate different refrigerant pressures and leakage rates during actual leakage. The second check valve 12 is used to prevent water in the water pipeline simulation system 1 of the heat pump unit from flowing back into the gas filling system 3.

[0028] An external water pipeline simulation system 2 is connected between the inlet and outlet of the internal water pipeline simulation system 1 of the heat pump unit, and is used to simulate the operating conditions of the external water pipeline of the heat pump unit. The external water pipeline simulation system 2 includes an inlet pipeline 15, the inlet end of which is connected to a booster pump 31, and the outlet end of which is connected to a first branch 16 and a second branch 17 respectively. The other end of the first branch 16 is connected to the outlet of an electric shut-off valve 7. A third shut-off valve 30 is installed on the pipeline of the first branch 16, and a second safety component is installed at the outlet of the third shut-off valve 30. The other end of the second branch 17 is connected to the inlet of a first check valve 4. A manual regulating valve 18, a water pump 19, a flow meter 20, and an expansion tank 21 are installed sequentially along the water flow direction on the second branch 17.

[0029] Specifically, the inlet pipe 15 is used to connect to external water supply to add or drain water to the entire system; the booster pump 31 is used to pressurize the water in the system and adjust the system pressure to the water-side pressure of the heat pump unit to be simulated; the water pump 19 has a flow regulation function and can be used with the manual regulating valve 18 to adjust the flow for small flow rates; the flow meter 20 is used to display the system flow rate; and the expansion tank 21 is used to help stabilize the system pressure.

[0030] Furthermore, both the first safety component and the second safety component include a safety valve 23, an automatic exhaust valve 24, and a pressure gauge 25 installed in parallel.

[0031] Specifically, before testing, during the water filling process, if there is air in the system pipeline, the second shut-off valve 22 and the third shut-off valve 30 can be opened, and the air in the system can be discharged by the automatic air vent valve 24 in the first and second safety components. After the flow and pressure of the water system stabilize, the second shut-off valve 22 is closed, and the third shut-off valve 30 is in the normally open state. When the gas filling test begins, the injected refrigerant gas is stored in the air vent 6. The first safety component does not work. Due to the high gas pressure in the system, the safety valve 23 in the second safety component plays a pressure relief role, so that the water system pressure is always stable within the set pressure range. When the required gas filling amount is large or the gas filling time is long, the volume of the air vent 6 is insufficient to hold all the gas. Then the second shut-off valve 22 is opened, so that the gas entering the air vent 6 is discharged from the automatic air vent valve 24 in the first safety component. At this time, the safety valve 23 in the first and second safety components simultaneously play a pressure relief and stabilization role, making the water pressure more stable.

[0032] It should be noted that the refrigerant leak detection device 5 in this utility model can be a vortex flow meter, which uses the turbulence characteristics of water to detect refrigerant leaks. The vortex flow meter is based on the Karman vortex street principle. A vortex generator is set in the measuring pipeline. After the fluid flows through, regular vortices will be generated alternately on both sides of the vortex generator. By measuring the vortex generation frequency and the width of the vortex generator, the fluid velocity can be calculated, and thus the flow rate can be obtained. The output of the vortex flow meter is a frequency signal. When the fluid contains air bubbles, it will change the turbulence characteristics of the fluid and affect the regularity of vortex generation. At this time, the flow meter output frequency is abnormal, such as rapidly increasing, decreasing or oscillating. After receiving this abnormal frequency signal, the controller 8 will determine that gas has leaked into the fluid, and then control the electric shut-off valve 7 to close. However, this utility model is not limited to detecting refrigerant leaks based on the turbulence characteristics of water. Detecting refrigerant leaks by measuring water flow rate and changes in water level in the device is also within the protection scope of this utility model.

[0033] The working process of this utility model is as follows: First, water is added to the entire test system through the water inlet pipe 15. The second shut-off valve 22 and the third shut-off valve 30 are opened. The first and second safety components are used to vent the entire test system. At the same time, the water pump 19 is turned on. The water flow rate of the test system is adjusted to the water-side flow rate of the heat pump unit to be simulated through the water pump 19 and the manual regulating valve 18. The system pressure is adjusted to the water-side pressure of the heat pump unit to be simulated through the pressurization pump 31. After the flow rate and pressure of the test system stabilize, the second shut-off valve 22 is closed. The pressure reducing valve 11 and the fine-tuning valve 13 in the gas injection system 3 are adjusted. The first shut-off valve 14 is opened, and the gas enters the test system. The refrigerant leak detection device 5 flows into the water. After a certain response time, the refrigerant leak detection device 5 outputs an abnormal signal to the controller 8. The controller 8 outputs a feedback signal to perform a protective action, controlling the electric shut-off valve 7 to close. After the electric shut-off valve 7 closes, it works in conjunction with the first check valve 4, which is equivalent to cutting off the unit's water system from the user side after an actual leak. After the test, the gas filling system 3 is closed first, and then the second shut-off valve 22 on the top of the exhaust tank 6 is opened. The stored gas will be discharged from the automatic exhaust valve 24 in the first safety component. During the test, the response time of the refrigerant leak detection device 5 can be recorded and the protection functions of the controller 8, electric shut-off valve 7, and other components can be verified.

[0034] Example 2

[0035] like Figure 2 As shown, unlike Embodiment 1, an electric heater 26 is installed on the second branch 17 between the manual regulating valve 18 and the water pump 19. The electric heater 26 heats the water in the test system to simulate the actual hot water outlet temperature of the heat pump unit and improve the realism of the simulation.

[0036] Furthermore, pressure taps 27 are provided on both sides of the pipelines of the first check valve 4 and the refrigerant leakage detection device 5. The pressure taps 27 on both sides are connected to the differential pressure sensor 29 through conduits 28. The first check valve 4 and the refrigerant leakage detection device 5 are components of the heat pump unit in the test system. It is necessary to measure their water resistance under different water flow rates to ensure the stability of the heat pump unit operation. Therefore, by setting pressure taps 27 upstream and downstream of the first check valve 4 and the refrigerant leakage detection device 5, and connecting them to the differential pressure sensor 29 through conduits 28, the differential pressure sensor 29 can directly display the pressure difference, i.e., the water resistance, of the relevant components upstream and downstream.

[0037] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A test system for simulating refrigerant leaks and detection, comprising: The application relates to a water pipeline simulation system for a heat pump unit. The water pipeline simulation system comprises a first check valve, a refrigerant leakage detection device connected to the water outlet end of the first check valve, an exhaust tank connected to the water outlet end of the refrigerant leakage detection device, and an electric cut-off valve connected to the water outlet end of the exhaust tank. The refrigerant leakage detection device is electrically connected to the input end of a controller, and the output end of the controller is electrically connected to the electric cut-off valve. The first safety assembly is installed at the exhaust port of the exhaust tank through a second cut-off valve. The pipeline between the first check valve and the refrigerant leakage detection device is provided with an air inlet.

2. The test system of claim 1, wherein: The gas filling system comprises a gas cylinder, a pressure reducing valve, a second check valve, a fine adjustment valve and a first cut-off valve connected in sequence to the valve port of the gas cylinder.

3. The test system of claim 1, wherein: The outlet of the first cut-off valve is connected to the air inlet.

4. The test system of claim 3, wherein: The water pipeline simulation system comprises a water inlet pipeline.

5. The test system for simulating refrigerant leakage and detection of claim 3, wherein: The water outlet end of the water inlet pipeline is connected to a first branch and a second branch.

6. The test system of claim 1, wherein: The other end of the first branch is connected to the water outlet of the electric cut-off valve. A third cut-off valve is installed on the first branch. The second safety assembly is installed at the outlet of the third cut-off valve. The other end of the second branch is connected to the water inlet of the first check valve. A manual regulating valve, a water pump, a flow meter and an expansion tank are installed in sequence on the second branch along the water flow direction. The first safety assembly and the second safety assembly each comprise a safety valve, an automatic exhaust valve and a pressure gauge installed in parallel. An electric heater is installed on the second branch between the manual regulating valve and the water pump. Pressure taps are arranged on the pipelines on both sides of the first check valve and the refrigerant leakage detection device. The pressure taps on both sides are respectively connected to a differential pressure sensor through a conduit.

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