Circulating liquid temperature control system and control method

Abstract

The invention discloses a circulating liquid temperature control system and method, and the system comprises a refrigeration module which transmits the energy of a cold source to a circulating liquid in a circulating liquid module through an evaporator; according to the circulating liquid module, circulating liquid receives energy from the refrigeration module through an evaporator, temperature adjustment is conducted through a heater, and the circulating liquid flows back to the evaporator again after being conveyed to a load through a distribution pipe through a water pump; the heater is communicated with the liquid storage tank, and the liquid storage tank is used for supplementing circulating liquid; and the control module is used for collecting operation parameters of the circulating liquid temperature control system and controlling the refrigeration module and the circulating liquid module to work. According to the invention, the circulating liquid temperature control system can work normally under the conditions of long piping and high-low fall; according to the circulating liquid temperature control system, the exhaust device of the whole system is additionally arranged, so that gas in the long piping can be exhausted from the circulating liquid temperature controller in time, meanwhile, the problem that the heater is prone to empty burning after the structure of the circulating liquid temperature control system is improved is solved, and the working stability and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature control equipment, and particularly to a circulating liquid temperature control system and a control method thereof. Background Art

[0002] A circulating liquid thermostat is a device that controls the temperature of a liquid and commonly used in industrial production, which includes water cooling and air cooling. It can provide a circulating liquid with constant temperature, constant flow, and constant pressure for the load to meet the required temperature rise, temperature drop, and constant temperature requirements. Before working, the circulating liquid thermostat needs to inject a specified amount of circulating liquid into its own water tank. In the refrigeration mode, the circulating liquid is cooled by the refrigeration system of the circulating liquid thermostat, and then the low-temperature circulating liquid is sent to the load that needs to be cooled by a water pump. The circulating liquid exchanges heat with the load, takes away heat, and the temperature rises. Then it flows back to the evaporator and is cooled by the refrigeration system. This cycle is repeated to achieve the cooling effect of the equipment, and the heating process is the opposite. The existing circulating liquid thermostats can work normally in the case of short pipelines, but in the actual use environment, there will be situations where the thermostat works with a pipeline of dozens of meters for the target load, and there are also height differences of up to several meters or even more than ten meters along with this usage condition. In this case, there will be problems such as only the front end of the circulating liquid outlet in the long pipeline having liquid, no liquid in the circulating liquid inlet pipeline, and a large amount of gas in the liquid in the front pipeline; the water pump makes abnormal noises and runs idly, etc., seriously affecting the working stability of the temperature control system and the accuracy of temperature control.

[0003] "A Circulating Liquid Temperature Control Device" disclosed in the Chinese patent literature, with the publication number CN115654771A and the publication date of January 31, 2023, includes an adjustment circuit. The adjustment circuit includes a compressor, a four-way reversing valve is connected to one side of the compressor, the four-way reversing valve is connected to a heat exchanger, the heat exchanger is connected to a first temperature control component, the first temperature control component is connected to a heat exchange component, the heat exchange component is connected to the other side of the compressor, the first temperature control component is also connected to a second temperature control component, and a circuit is formed between the first temperature control component and the second temperature control component and the heat exchanger; the adjustment circuit is connected to a circulating liquid circuit flowing through the load. It solves the problems of low energy efficiency ratio, slow response, and low precision existing in the current circulating liquid temperature control device; this technology can achieve the refrigeration and heating of the circulating liquid by setting an adjustment circuit and a circulating liquid circuit; by setting temperature control components, precise temperature control can be achieved, and the pressure in the circuit can be kept stable. However, this technology is only applicable to the case of short pipelines. When working with a long pipeline for the target load, problems such as no liquid in the circulating liquid inlet pipeline, a large amount of gas in the liquid in the pipeline, and abnormal noises of the water pump are likely to occur, seriously affecting the working stability and temperature control accuracy. Summary of the Invention

[0004] The present invention aims to overcome the problems of the existing circulating liquid temperature control system, which is only applicable to normal operation in the case of short piping. When working on a target load with long piping, situations such as no liquid in the circulating liquid inlet pipeline, a large amount of gas in the pipeline liquid, and abnormal noise of the water pump are likely to occur, seriously affecting the working stability and temperature control accuracy. A circulating liquid temperature control system and a control method are provided.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A circulating liquid temperature control system, comprising: A refrigeration module that transfers the energy of the cold source to the circulating liquid in the circulating liquid module through an evaporator; A circulating liquid module, where the circulating liquid receives the energy from the refrigeration module through the evaporator, undergoes temperature adjustment through a heater, and is pumped by a water pump through a pipeline to the load and then returns to the evaporator; the heater is communicated with a liquid storage tank, and the liquid storage tank replenishes the circulating liquid; A control module that collects the operating parameters of the circulating liquid temperature control system and controls the operation of the refrigeration module and the circulating liquid module.

[0006] The circulating liquid temperature control system in the present invention is a temperature control device with high energy efficiency ratio, fast response, and high precision. It supplies the circulating liquid to the load through vapor compression cooling and heater heating to achieve the purpose of precise temperature control. At the same time, through the improvement of the specific structure, the circulating liquid temperature control system can work normally in the case of long piping and height differences; an exhaust device for the whole system is added, which can timely discharge the gas in the long piping from the circulating liquid thermostat, avoiding liquid splashing when the water tank cover is opened due to a large amount of gas stored inside the water tank; the internal pipeline of the circulating liquid temperature control system is simplified, reducing energy loss and improving the cop; at the same time, the problem that the heater is prone to dry burning after the structure of the circulating liquid temperature control system is improved is solved, improving the working stability and reliability.

[0007] Preferably, the circulating liquid module includes an evaporator. The circulating liquid output end of the evaporator is connected to the inlet of the heater through a heater liquid delivery pipe, the outlet of the heater is connected to the inlet of the water pump through a water pump liquid replenishing pipe, the outlet of the water pump is connected to the inlet of the load through a circulating liquid outlet pipe, and the outlet of the load is connected to the circulating liquid input end of the evaporator through a circulating liquid return pipe.

[0008] Preferably, the liquid storage tank is communicated with the heater through a heater liquid replenishing pipe to replenish the circulating liquid in the liquid storage tank into the heater; The heater is also communicated with the liquid storage tank through a heater exhaust pipe to discharge the gas in the heater into the liquid storage tank.

[0009] Preferably, a circulating liquid drain port is connected to the water pump liquid supplement pipe between the heater and the water pump, and a sixth valve is provided at the circulating liquid drain port; The circulating liquid outlet pipe and the circulating liquid return pipe are connected through a circulating liquid return loop, and a third valve is provided on the circulating liquid return loop.

[0010] Preferably, a fifth valve is provided at one end of the circulating liquid outlet pipe close to the load, a fourth valve is provided at one end of the circulating liquid return pipe close to the load, and a second filter is provided at one end of the fourth valve away from the load; A first temperature sensor is provided at one end of the circulating liquid outlet pipe close to the water pump, and a second temperature sensor is provided at one end of the second filter close to the evaporator.

[0011] Preferably, the heater exhaust pipe enters the liquid storage tank vertically, the outlet of the heater exhaust pipe is close to the top of the liquid storage tank and higher than the liquid level in the liquid storage tank; the diameter of the heater liquid supplement pipe is larger than the diameters of other pipelines in the circulating liquid module; an exhaust pipe is provided on the liquid storage tank, and a one-way valve is provided on the exhaust pipe.

[0012] Preferably, the water pump is located below the heater, and the outlet of the heater is located at the bottom of the heater.

[0013] Preferably, a flow meter is provided in the circulating liquid module to measure the flow rate of the circulating liquid, and the flow meter is provided at a position on the circulating liquid return pipe close to the evaporator; A temperature protector is provided on the heater to monitor the heating temperature in the heater.

[0014] A control method for a circulating liquid temperature control system includes: Circulate the circulating liquid when the heater is not started, and measure the flow rate of the circulating liquid at a position on the circulating liquid return pipe close to the evaporator; judge the stability of the circulating liquid flow rate; If the stability of the circulating liquid flow rate meets the requirements, start the heater; otherwise, continuously circulate the circulating liquid without starting the heater until the stability requirements are met.

[0015] Preferably, after starting the heater to heat the circulating liquid, monitor the heating temperature in the heater through the temperature protector; when the monitored heating temperature exceeds the preset temperature threshold, stop the operation of the heater and give an alarm.

[0016] The present invention has the following beneficial effects: Through the improvement of the specific structure, the circulating liquid temperature control system can work normally under the conditions of long piping and height difference; the exhaust device of the whole system is added, which can discharge the gas in the long piping from the circulating liquid thermostat in time, avoiding the liquid splash when the water tank cover is opened due to a large amount of gas stored inside the water tank; the internal pipeline of the circulating liquid temperature control system is simplified, reducing energy loss and improving the COP; at the same time, the problem that the heater is prone to dry burning after the structure of the circulating liquid temperature control system is improved is solved, improving the working stability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. is a schematic diagram of the circulating liquid temperature control system in the present invention.

[0018] Figure 2 FIG. is a schematic diagram of the structure on one side of the circulating liquid module in the present invention.

[0019] Figure 3 FIG. is a schematic diagram of the structure on the other side of the circulating liquid module in the present invention.

[0020] Figure 4 FIG. is a schematic diagram of the circulating liquid module in the present invention.

[0021] Figure 5 FIG. is a schematic diagram of an existing circulating liquid module.

[0022] Figure 6 FIG. is a flowchart of the control method of the circulating liquid temperature control system in the present invention.

[0023] In the figure: 1, variable frequency compressor; 2, first pressure sensor; 3, hot bypass circuit; 31, first electronic expansion valve; 4, condenser; 5, cooling water inlet pipe; 51, first filter; 52, first valve; 6, cooling water outlet pipe; 61, second valve; 7, plant water system; 8, dryer filter; 9, sight glass; 10, return circuit; 101, second electronic expansion valve; 11, refrigeration circuit; 111, third electronic expansion valve; 12, second pressure sensor; 13, evaporator; 14, liquid storage tank; 141, liquid storage tank cover; 142, exhaust pipe; 143, heater liquid supply pipe; 144, heater exhaust pipe; 15, liquid level gauge; 16, heater; 161, heater liquid delivery pipe; 17, high temperature protector; 18, low temperature protector; 19, water pump; 191, water pump liquid supply pipe; 20, water pressure gauge; 21, first temperature sensor; 22, circulating liquid return circuit; 221, third valve; 23, second temperature sensor; 24, flow meter; 25, circulating liquid return pipe; 251, Y-shaped second filter; 252, fourth valve; 26, circulating liquid outlet pipe; 261, fifth valve; 27, circulating liquid drain port; 271, sixth valve; 28, load. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0025] The circulating liquid thermostat plays an important role in fields such as medical treatment and semiconductors. With the development of technology, scientific research institutions have continuously increased their requirements for the precision of equipment and instruments. Among them, there are requirements for controlling the temperature and temperature stability of experimental targets. The existing circulating liquid thermostat can work normally during short pipe matching, but in the actual use environment, it will encounter the situation where the thermostat works with a load of dozens of meters of pipelines, and along with this usage condition, there are height differences of up to several meters or even more than ten meters. In this case, there will be only liquid at the front end of the circulating liquid outlet in the long pipe, no liquid in the circulating liquid inlet pipeline, and a large amount of gas in the liquid in the front pipeline; the water pump makes abnormal noises and has an idling phenomenon, etc., seriously affecting the working stability of the temperature control system and the accuracy of temperature control.

[0026] In order to solve the problems existing in the prior art, the present invention provides a Figure 1 circulating liquid temperature control system as shown in a refrigeration module that transfers the energy of the cold source to the circulating liquid in the circulating liquid module through the evaporator; a circulating liquid module, where the circulating liquid receives the energy from the refrigeration module through the evaporator, undergoes temperature adjustment through the heater, and is pumped by the water pump through the pipeline to the load and then returns to the evaporator; the heater is connected to the liquid storage tank, and the liquid storage tank replenishes the circulating liquid; a control module that collects the operating parameters of the circulating liquid temperature control system and controls the operation of the refrigeration module and the circulating liquid module.

[0027] It should be noted that the circulating liquid temperature control system in the present invention is a temperature control device with high energy efficiency ratio, fast response, and high precision. It supplies the circulating liquid to the load through the steam compression cooling and heater heating methods to achieve the purpose of precise temperature control. At the same time, through the improvement of the specific structure, the circulating liquid temperature control system can work normally in the case of long pipelines and height differences; an exhaust device for the entire system is added, which can timely discharge the gas in the long pipeline from the circulating liquid thermostat, avoiding liquid splashing when the water tank cover is opened due to a large amount of gas stored inside the water tank; the internal pipeline of the circulating liquid temperature control system is simplified, reducing energy loss and improving the cop; at the same time, the problem that the heater is prone to dry burning after the structural improvement of the circulating liquid temperature control system is solved, improving the working stability and reliability.

[0028] It should be noted that the circulating liquid temperature control system mainly consists of three modules, namely the refrigeration module, the circulating liquid module and the control module. The refrigeration module and the circulating liquid module are physically connected structures. The control module controls the opening and closing of each valve by collecting the operating parameters on the refrigeration module and the circulating liquid module, so as to realize the control of different working states of the circulating liquid temperature control system. The refrigeration module provides a cold source for the temperature control system. The circulating liquid module transfers the energy of the refrigeration module to the circulating liquid through the evaporator, then adjusts the temperature through the heater in the circulating liquid module, and finally transports the circulating liquid at an appropriate temperature to the load through the water pump in the circulating module. In the present invention, the improvement is mainly aimed at the actual structure of the circulating liquid module.

[0029] As a specific embodiment, the refrigeration module includes a condenser 4. The refrigerant output end of the condenser 4 is connected to the refrigerant input end of the evaporator 13 through a refrigeration circuit 11 with a third electronic expansion valve 111. The refrigerant output end of the evaporator 13 is connected to the inlet of the variable frequency compressor 1. A second pressure sensor 12 (which is a low-pressure sensor) is provided near the inlet of the variable frequency compressor 1. The outlet of the variable frequency compressor 1 is connected to the refrigerant input end of the condenser 4. A first pressure sensor 2 (which is a high-pressure sensor) is provided near the outlet of the variable frequency compressor 1.

[0030] The cooling water output end of the condenser 4 is connected to the inlet of the plant utility water system 7 through a cooling water outlet pipe 6. The outlet of the plant utility water system 7 is connected to the cooling water input end of the condenser 4 through a cooling water inlet pipe 5. A second valve 61 is provided on the cooling water outlet pipe 6. A first valve 52 and a first filter 51 (the first filter is a Y-type filter) are sequentially provided on the cooling water inlet pipe 5 from the plant utility water system 7 to the condenser 4.

[0031] It should be noted that the refrigeration module part has a refrigeration circuit part formed by a variable frequency compressor 1, a condenser 4, a third electronic expansion valve 111, an evaporator 13 and the pipes connected in series therewith, which are controlled by a variable frequency power supply to adjust the speed. After being compressed by the variable frequency compressor 1, the refrigerant becomes a high-temperature and high-pressure gas state and enters the condenser 4. The low-temperature cooling water in the plant utility water system 7 passes through the first valve 52 and the first filter 51, and flows from the cooling water inlet pipe 5 to the condenser 4 to transfer the heat of the condenser 4. The refrigerant passing through the condenser 4 becomes a medium-temperature and high-pressure liquid, flows through a drying filter 8 and a sight glass 9 in sequence, and becomes a low-temperature and low-pressure gas-liquid two-phase state through the throttling action of the third electronic expansion valve 111. Then, through the evaporator 13, the refrigerant exchanges heat with the circulating liquid, and the refrigerant absorbs the heat of the circulating liquid, reducing the temperature of the circulating liquid. The refrigerant is converted from a low-temperature and low-pressure gas-liquid two-phase state to a low-temperature and low-pressure gas, and flows back to the variable frequency compressor 1, completing one cycle of the refrigerant circuit. The circulating liquid whose heat is absorbed by the refrigerant is transported to the load that needs to be temperature-controlled by the customer through a water pump 19, playing a role in temperature control.

[0032] Further, in addition to the refrigeration circuit portion, the refrigeration module further includes a hot bypass circuit 3 and a return circuit 10. The hot bypass circuit 3 is connected between the outlet of the variable-frequency compressor 1 and the refrigerant input end of the evaporator 13, and a first electronic expansion valve 31 is provided therein; the return circuit 10 is connected between the refrigerant output end of the condenser 4 and the inlet of the variable-frequency compressor 1, and a second electronic expansion valve 101 is provided therein; between the inlet of the return circuit 10 and the refrigerant output end of the condenser 4, a drying filter 8 and a sight glass 9 are sequentially connected.

[0033] As a specific embodiment, as Figure 1 shown, the circulating liquid module includes an evaporator 13. The circulating liquid output end of the evaporator 13 is connected to the inlet of a heater 16 through a heater liquid delivery pipe 161. The outlet of the heater 16 is connected to the inlet of a water pump 19 through a water pump liquid supply pipe 191. The outlet of the water pump 19 is connected to the inlet of a load 28 through a circulating liquid outlet pipe 26. The outlet of the load 28 is connected to the circulating liquid input end of the evaporator 13 through a circulating liquid return pipe 25. A circulating liquid drain port 27 is connected to the water pump liquid supply pipe 191 between the heater 16 and the water pump 19, and a sixth valve 271 is provided at the circulating liquid drain port 27; the circulating liquid outlet pipe 26 and the circulating liquid return pipe 25 are connected through a circulating liquid return circuit 22, and a third valve 221 is provided on the circulating liquid return circuit 22.

[0034] It should be noted that the circulating liquid flowing out of the evaporator 13 enters the heater 16 for heating, and the heated circulating liquid is then transported by the water pump 19 to the circulating liquid outlet pipe 26 and flows to the load 28 to control the temperature of the load 28 through heat exchange; the circulating liquid flowing through the load 28 then flows back to the circulating liquid input end of the evaporator 13 through the circulating liquid return pipe 25 to complete the temperature control cycle. In addition, a circulating liquid drain port 27 is connected to the water pump liquid supply pipe 191 between the heater 16 and the water pump 19, and the circulating liquid that has undergone multiple cycles can be discharged, and new circulating liquid can be replenished to operate the circulating liquid module. The sixth valve 271 controls whether to discharge the circulating liquid that needs to be discarded by closing and opening.

[0035] It should be noted that a fifth valve 261 is provided at one end of the circulating liquid outlet pipe 26 close to the load 28, and a fourth valve 252 is provided at one end of the circulating liquid return pipe 25 close to the load 28. A second filter 251 (the second filter is a Y-type filter) is provided at one end of the fourth valve 252 away from the load 28; a flow meter 24 is also provided at the input end of the circulating liquid return pipe 25 close to the evaporator 13 to detect the flow rate of the circulating liquid flowing back in the circulating liquid return pipe 25. A first temperature sensor 21 and a water pressure gauge 20 are provided at one end of the circulating liquid outlet pipe 26 close to the water pump 19, and a second temperature sensor 23 is provided at one end of the second filter 251 close to the evaporator 13. All valves in the system are connected to the control module, and the opening or closing of the valves can be controlled by specific instructions of the control module, so as to control the connection situation of the corresponding pipelines.

[0036] Furthermore, when the circulating liquid module performs the circulating operation of the circulating liquid, due to the discharge of the waste gas circulating liquid or other various influencing factors, the circulating liquid in the pipelines of the circulating liquid module may not be in a full state. In this case, it is necessary to supplement the circulating liquid in the pipelines of the circulating liquid module. In the entire circulating liquid module, the key lies in the situation of the circulating liquid at the heater. In order to avoid dry burning of the heating device in the heater, it is necessary to ensure that the entire heating device is submerged in the circulating liquid, and the amount of circulating liquid flowing out of the heater and flowing into the heater is balanced. Therefore, the source of the supplement of the circulating liquid in the heater can come from the evaporator in addition to the liquid storage tank.

[0037] Specifically, the liquid storage tank 14 is communicated with the heater 16 through a heater liquid supply pipe 143 to supplement the circulating liquid in the liquid storage tank 14 into the heater 16; the heater 16 is also communicated with the liquid storage tank 14 through a heater exhaust pipe 144 to discharge the gas in the heater 16 into the liquid storage tank 14.

[0038] It should be noted that a certain amount of circulating liquid is stored in the liquid storage tank 14, and there is a certain gap between the liquid level of the circulating liquid and the top of the liquid storage tank 14. A liquid storage tank cover 141 is provided on the liquid storage tank 14. After the liquid storage tank cover 141 is opened, new circulating liquid can be added to the liquid storage tank 14. An exhaust pipe 142 is also provided on the liquid storage tank 14. After the gas from the heater 16 is discharged into the liquid storage tank 14, it is discharged from the exhaust pipe 142. A liquid level gauge 15 is also provided in the liquid storage tank 14. A high-temperature protector 17 and a low-temperature protector 18 are also provided on the heater 16 to ensure that the heater 16 is within the normal working temperature range.

[0039] Such as Figure 5Shown is a schematic diagram of an existing circulating liquid module. The liquid storage tank 14 and the circulating liquid flowing through the evaporator 13 supply liquid to the heater 16. The heater 16 then supplies liquid to the water pump 19 through the water pump liquid supply pipe 191. Finally, the water pump 19 outputs the circulating liquid to the load 28 end of the customer. In the scenario of using short pipes (the total pipe length of the circulating liquid temperature control system connecting to the customer's load end does not exceed 10 m), this set of water circuit systems can work properly. However, after converting to the scenario of using long pipes (when the total pipe length of the circulating liquid temperature control system connecting to the customer's load end is about 40 m or other longer distances), the following problems will occur in this set of water circuit systems.

[0040] First, there is only liquid at the circulating liquid output end of the evaporator in the long pipe, and there is no liquid in the circulating liquid input end pipe near the evaporator, and the liquid in the circulating liquid pipe contains a large amount of gas. Second, the water pump makes abnormal noises and shows an idling phenomenon. Third, there is a large amount of gas in the liquid storage tank, and obvious high-pressure expansion will occur when the liquid storage tank cover is opened.

[0041] Regarding the above problems, the entire circulating liquid module was disassembled and analyzed. It is considered that the main reason for the failure is that compared with short pipes, long pipes require more air to be discharged from the pipes, and the currently designed circulating liquid module does not have a device configured to discharge a large amount of exhaust gas.

[0042] In the subsequent improvement, first, an experimental verification was carried out on setting an external exhaust valve for the exhaust direction. The external exhaust valve was respectively installed at the liquid outlet and liquid inlet of the circulating liquid module for simulation experiments. It was found that the effect of external exhaust is very limited. Although the external exhaust valve can discharge gas, the exhaust volume is limited, and the above-mentioned faults have not been improved. The pipe exhaust scheme has also changed direction due to problems such as the risk of liquid leakage. Then the focus of the transformation was shifted to the water pump. It is considered that the generation of the exhaust problem may also be caused by the water pump not injecting the circulating liquid into the long pipe, so that the air in the long pipe is replaced by the circulating liquid. Analyzing in the direction of the water pump liquid supply, it is found that there are two sources of water pump liquid. One is that the liquid storage tank supplies liquid to the heater, and the water pump then sucks the circulating liquid from the heater. The other is that after the circulating liquid module operates normally, the liquid returning from the load flows through the evaporator again to the heater and is then sucked by the water pump. In the case of long pipes, it is impossible to circulate the liquid normally again, so the current liquid source of the water pump is only the liquid supply from the liquid storage tank. And in the design of the existing circulating liquid module, in order to prevent the heater from dry burning, the liquid suction port of the water pump is placed at the upper end of the heater, as Figure 5 shown. In this way, it is necessary for the liquid storage tank to fill the heater first before the water pump can suck the circulating liquid. Tests have found that the liquid supply speed of the liquid storage tank is slower than the liquid suction speed of the heater, resulting in the water pump idling.

[0043] Therefore, in a long piping system, the harsh usage conditions prevent the water pump from receiving the system's returned liquid to replenish the circulating liquid. The insufficient liquid replenishment of the water pump causes the pump to run idly. The idle running of the pump results in insufficient liquid discharge, and the lack of liquid discharge ultimately leads to the inability of the entire system to return liquid. The problem has become a closed loop. To break this closed loop, considerations are made from the perspective of the liquid replenishment volume of the water pump. What needs to be done is to increase the liquid replenishment speed of the liquid storage tank to the heater so that it is greater than the liquid suction speed of the water pump to the heater.

[0044] In the present invention, as Figure 2 , Figure 3 and Figure 4 shown, the specific improved structure of the circulating liquid module is that the water pump 19 is located below the heater 16, and the outlet of the heater 16 is at the bottom of the heater 16. The heater exhaust pipe 144 enters the liquid storage tank 14 vertically, and the outlet of the heater exhaust pipe 144 is close to the top of the liquid storage tank 14 and higher than the liquid level in the liquid storage tank 14; the diameter of the heater liquid replenishment pipe 143 is larger than that of other pipelines in the circulating liquid module; a exhaust pipe 142 is provided on the liquid storage tank 14, and a one-way valve is provided on the exhaust pipe 142. A flow meter 24 is provided in the circulating liquid module to measure the flow rate of the circulating liquid, and the flow meter 24 is arranged at the circulating liquid return pipe 25 near the evaporator 13; a temperature protector is provided on the heater 16 to monitor the heating temperature in the heater, and the temperature protector includes a low-temperature protector 18 and a high-temperature protector 17.

[0045] It should be noted that to make the liquid replenishment speed of the liquid storage tank 14 to the heater 16 greater than the liquid suction speed of the water pump 19 to the heater 16, first, the liquid replenishment port of the heater 16 to the water pump 19 is moved to the lower end to avoid the need to fill the heater 16 to full liquid before providing liquid to the water pump 19. This modification enables the heater 16 to directly provide circulating liquid to the water pump 19 after receiving the circulating liquid. However, this will cause the problem of dry burning of the heater 16. The reason for the dry burning problem is that when the heater 16 operates, the inside is not fully filled with liquid, and the heating device inside the heater 16 continuously heats without heat exchange. Dry burning will lead to the following three situations.

[0046] Overheating: The heating device continuously heats without a load, which may cause the device temperature to be too high, and may even burn out the device or cause a fire. Damaging the heater: Prolonged dry burning will cause the heating device inside the heater to be damaged due to overheating, thereby shortening the service life of the heater. Energy waste: The heater still consumes electric energy without an object, which will cause unnecessary energy waste.

[0047] To solve the problem of the heater running dry, one or more of the following combined methods are adopted in the present invention. 1. An exhaust pipe with a one-way valve (the direction is from the liquid storage tank to the outside) is added at the liquid storage tank as the exhaust device of the liquid storage tank, so that gas can be discharged from the liquid storage tank at any time during operation, reducing the air content in the heater, thereby increasing the liquid replenishment speed of the liquid storage tank to the heater. 2. Increase the diameter of the liquid replenishment pipe from the liquid storage tank to the heater to improve the liquid replenishment flow rate to the heater. 3. The exhaust pipe leading from the heater to the liquid storage tank enters the liquid storage tank vertically to increase the exhaust speed in the heater. 4. The control module is used to control the heater to start after the circulating liquid circulates normally. The circulating liquid module judges whether the circulating liquid circulates normally by detecting whether the flow rate of the circulating liquid is stable through the built-in flow meter. 5. A temperature protector is added in the heater to monitor the temperature of the heater. Once it runs dry, the power supply of the whole machine will be cut off. After the above improvements, the circulating liquid temperature control system can operate normally under the condition of long pipeline.

[0048] In addition to providing a circulating liquid temperature control system, the present invention also provides a control method for a circulating liquid temperature control system as shown in Figure 6 and includes: Circulate the circulating liquid when the heater is not started, and measure the flow rate of the circulating liquid near the evaporator in the circulating liquid return pipe; judge the stability of the circulating liquid flow rate; If the stability of the circulating liquid flow rate meets the requirements, start the heater; otherwise, continuously circulate the circulating liquid without starting the heater until the stability requirements are met.

[0049] It should be noted that the control method of the present invention is stored in the control module correspondingly. After the control module obtains the detection data of the flow meter, it processes the circulating liquid flow rate according to the preset data processing method, judges whether it meets the stability requirements, and executes the corresponding operation of starting the heater or not starting the heater according to the final result. When the circulating liquid flow rate is stable, it indicates that the circulating liquid in the circulating liquid module can flow out of the heater normally, exchange heat through the load, and then return to the evaporator to complete the whole cycle. At this time, it indicates that the circulating liquid flowing into and out of the heater is relatively balanced, and the liquid replenishment of the liquid storage tank to the heater can avoid the heater running dry. If the circulating liquid flow rate is unstable, it may occur that the circulating liquid flowing out of the heater is more than the circulating liquid flowing in, and there is a risk of running dry. Therefore, the heater needs to be started after the circulating liquid flow rate is stable.

[0050] It should be noted that there are various different ways to judge the stability of the circulating liquid flow rate. First, after the flow meter obtains the circulating liquid flow rate data within a period of time, the maximum value and the minimum value can be selected to calculate the difference. If the difference is less than the preset difference threshold, it indicates that the circulating liquid flow rate is in a stable state; alternatively, the variance or standard deviation of the circulating liquid flow rate data within a period of time can be calculated. If the variance or standard deviation is less than the difference threshold, it can also indicate that the circulating liquid flow rate is in a stable state.

[0051] After starting the heater to heat the circulating liquid, the heating temperature in the heater is monitored by the temperature protector; when the monitored heating temperature exceeds the preset temperature threshold, the heater is stopped and an alarm is issued. When the heater is in dry burning, since there is no circulating liquid object to be heated, its temperature will rise sharply far beyond the normal heating temperature. Therefore, when the temperature protector monitors that the heating temperature exceeds the normal temperature threshold, it can be judged that the heater is in dry burning state, and power needs to be cut off to stop working and an alarm is issued.

[0052] The above embodiments are further elaborations and explanations of the present invention for the convenience of understanding, and are not any limitations to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A circulating liquid temperature control system, characterized in that, Comprising: A refrigeration module that transfers the energy of a cold source to the circulating liquid in the circulating liquid module through an evaporator; A circulating liquid module, where the circulating liquid receives energy from the refrigeration module through the evaporator, undergoes temperature regulation through a heater, and is pumped by a water pump through a pipe to the load and then returns to the evaporator; the heater is connected to a liquid storage tank, and the liquid storage tank replenishes the circulating liquid; A control module that collects the operating parameters of the circulating liquid temperature control system and controls the operation of the refrigeration module and the circulating liquid module.

2. The circulating liquid temperature control system according to claim 1, wherein The circulating liquid module includes an evaporator. The circulating liquid output end of the evaporator is connected to the inlet of the heater through a heater liquid delivery pipe. The outlet of the heater is connected to the inlet of the water pump through a water pump liquid replenishing pipe. The outlet of the water pump is connected to the inlet of the load through a circulating liquid outlet pipe. The outlet of the load is connected to the circulating liquid input end of the evaporator through a circulating liquid return pipe.

3. The circulating liquid temperature control system according to claim 1 or 2, characterized in that, The liquid storage tank is connected to the heater through a heater liquid replenishing pipe to replenish the circulating liquid in the liquid storage tank into the heater; The heater is also connected to the liquid storage tank through a heater exhaust pipe to discharge the gas in the heater into the liquid storage tank.

4. A circulating liquid temperature control system according to claim 2, characterized in that A circulating liquid drain port is connected to the water pump liquid replenishing pipe between the heater and the water pump, and a sixth valve is provided at the circulating liquid drain port; The circulating liquid outlet pipe and the circulating liquid return pipe are connected through a circulating liquid return loop, and a third valve is provided on the circulating liquid return loop.

5. A circulating liquid temperature control system according to claim 2 or 4, characterized in that, A fifth valve is provided at one end of the circulating liquid outlet pipe close to the load, a fourth valve is provided at one end of the circulating liquid return pipe close to the load, and a second filter is provided at one end of the fourth valve away from the load; A first temperature sensor is provided at one end of the circulating liquid outlet pipe close to the water pump, and a second temperature sensor is provided at one end of the second filter close to the evaporator.

6. The circulating liquid temperature control system according to claim 3, characterized in that, The heater exhaust pipe vertically enters the liquid storage tank, and the outlet of the heater exhaust pipe is close to the top of the liquid storage tank and higher than the liquid level in the liquid storage tank; the diameter of the heater liquid replenishing pipe is larger than the diameters of other pipes in the circulating liquid module; an exhaust pipe is provided on the liquid storage tank, and a one-way valve is provided on the exhaust pipe.

7. A circulating liquid temperature control system according to claim 2 or 4 or 6, characterized in that, The water pump is located below the heater, and the outlet of the heater is located at the bottom of the heater.

8. A circulating liquid temperature control system according to claim 7, characterized in that, A flow meter is provided in the circulating liquid module to measure the flow rate of the circulating liquid, and the flow meter is provided at a position on the circulating liquid return pipe close to the evaporator; A temperature protector is provided on the heater to monitor the heating temperature in the heater.

9. A control method for a circulating liquid temperature control system, applicable to the circulating liquid temperature control system according to any one of claims 1-8, characterized in that, Comprising: Circulate the circulating liquid when the heater is not started, and measure the flow rate of the circulating liquid at a position on the circulating liquid return pipe close to the evaporator; Judge the stability of the circulating liquid flow rate; If the stability of the circulating liquid flow rate meets the requirements, start the heater; otherwise, continuously circulate the circulating liquid without starting the heater until the stability requirements are met.

10. The control method of a circulating liquid temperature control system according to claim 9, characterized in that, After starting the heater to heat the circulating liquid, monitor the heating temperature in the heater through the temperature protector; when the monitored heating temperature exceeds the preset temperature threshold, stop the operation of the heater and give an alarm.

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