Novel low-temperature refrigerating system based on electromagnetic valve liquid level control

Abstract

The invention discloses a novel low-temperature refrigerating system based on electromagnetic valve liquid level control, which belongs to the field of low-temperature refrigerating technology application and comprises a compressor, a condenser, a liquid storage tank, a liquid level sensor, a controller, an electromagnetic valve and an evaporator. According to the system, the scheme of throttling expansion of an expansion valve or a capillary tube is improved, a liquid storage tank is arranged behind a condenser to store condensed liquid refrigerant, the liquid level is measured through a liquid level sensor, when the liquid level reaches a set position, an electric signal is output through a controller, an electromagnetic valve is opened, and the liquid refrigerant is conveyed into an evaporator to be vaporized and absorb heat; the gaseous refrigerant is continuously condensed in the condenser, and enough liquid-phase refrigerant is always in the evaporator for phase change vaporization. The problem that in traditional throttling expansion, the refrigerant flow is insufficient due to the fact that the opening degree of an expansion device is too small can be solved, meanwhile, the liquid refrigerant entering the evaporator is directly sucked through an inlet of the compressor, a low-temperature and low-pressure refrigeration state is formed, it is guaranteed that the refrigerant flow and the refrigerating capacity are sufficient and controllable, and meanwhile the lower refrigeration temperature is achieved.

Description

Technical Field

[0001] The invention belongs to the field of low-temperature refrigeration technology application, and in particular relates to a novel low-temperature refrigeration system based on solenoid valve liquid level control. Background Art

[0002] Compression steam refrigeration is a process in which the refrigerant is repeatedly compressed, condensed, and expanded in a closed refrigeration system, and then evaporated to absorb heat to achieve cooling and refrigeration. It transfers heat energy from a low-temperature object to a high-temperature object by consuming electrical energy. It is the most widely used in the current refrigeration industry. In traditional refrigeration applications, the lowest effective refrigeration temperature that can be achieved through single-stage steam compression is usually above -40°C (233K). If you want to achieve a lower refrigeration temperature, such as in low-temperature cold storage, gas liquefaction and other scenarios, the refrigerant needs to reach a lower evaporation pressure to achieve a lower temperature.

[0003] The expansion process of the traditional refrigeration cycle requires the expansion and pressure reduction of high-pressure refrigerant through structures such as throttling expansion valves or capillaries. The enthalpy value before and after the process remains unchanged, but a large amount of kinetic energy is lost through friction loss during the pressure reduction process, resulting in reduced energy efficiency. At the same time, in order to achieve lower refrigeration temperature and pressure, its opening degree is often lower to achieve a greater refrigerant pressure drop. Considering that the expansion valve and capillary tube need to achieve pressure reduction through the rapid contraction of the refrigerant pipeline during throttling expansion, the high-pressure liquid refrigerant generated by the condenser will be significantly blocked when passing through a narrow pipe diameter, resulting in a significant decrease in the refrigerant flow rate through the throttling device to the subsequent evaporation link, and insufficient cooling capacity.

[0004] In order to overcome the above problems of the traditional refrigeration cycle, a new type of compressed steam refrigeration system is proposed. In this system, the liquid refrigerant in the condenser does not pass through the throttling device, but is directly input into the evaporator, and through the suction action of the compressor, it undergoes violent expansion and phase change vaporization in the evaporator. In this way, sufficient refrigerant flow can be maintained while ensuring a low evaporation pressure and temperature. In order to achieve the control and regulation of the refrigeration system, the scheme uses a liquid level sensor to measure the real-time liquid level in the condenser, and adjusts the amount of refrigerant discharged to the evaporator and the discharge interval through the controller to achieve the purpose of regulating the evaporation temperature and cooling capacity. Summary of the invention

[0005] In view of this, the present invention proposes a new low-temperature refrigeration system based on solenoid valve liquid level control, and its specific technical solution is as follows:

[0006] A new type of low-temperature refrigeration system based on solenoid valve liquid level control, consisting of a compressor, a condenser, a liquid storage tank, a liquid level sensor, a controller, a solenoid valve, an evaporator, etc.:

[0007] For the flow pipeline of the refrigerant, the compressor outlet is connected to the condenser inlet, the condenser outlet is connected to the liquid storage tank inlet, the liquid storage tank outlet is connected to the solenoid valve inlet, the solenoid valve outlet is connected to the evaporator refrigerant inlet, and the evaporator refrigerant outlet is connected to the compressor inlet;

[0008] The liquid level sensor is fixedly installed inside or on the outer surface of the liquid storage tank according to actual working needs, and the height can be set according to actual needs. The sensor is connected to the controller and the solenoid valve through a circuit. When the liquid level in the liquid storage tank does not reach the set height, the sensor is in an open circuit state, the system does not produce an action, and the refrigerant pipeline at the solenoid valve is in a closed state. When the liquid level reaches the set position of the sensor, the sensor closes and outputs an electrical signal to make the relay in the controller energize, and then outputs a signal to the solenoid valve to open it, so that the refrigerant passes. When the liquid level is lower than the set position, the liquid level sensor is open again, the control signal is disconnected, and the solenoid valve returns to the closed state, and then the work is repeated periodically.

[0009] Another object of the present invention is to provide a method for using the above system, the main working process of which includes:

[0010] During the refrigeration process, the high-temperature and high-pressure refrigerant output by the compressor is input into the condenser for cooling and liquefaction, and then the refrigerant is input into the liquid storage tank. Initially, the liquid level does not reach the height of the liquid level sensor, the solenoid valve is closed, the liquid accumulates in the liquid storage tank, and the liquid level gradually rises. When the liquid level reaches the position of the liquid level sensor, the sensor closes and outputs an electrical signal, and the solenoid valve is opened through the controller. The liquid refrigerant in the liquid storage tank is discharged into the evaporator in time, and the solenoid valve is closed again after the liquid level drops back. Under the strong suction effect of the compressor, the liquid refrigerant is forced to expand and reduce pressure and temperature in the evaporator, and the input air is cooled by heat exchange. The refrigerant after absorbing heat and vaporization is input into the compressor again, completing a refrigeration cycle.

[0011] Furthermore, the installation height of the liquid level sensor can be adjusted according to the actual system power and the refrigerant filling amount, and the drainage time after the solenoid valve is powered on each time can also be set according to needs.

[0012] Furthermore, the liquid level sensor may adopt various working types including but not limited to float type, buoy type, static pressure type, capacitance type, optical type and the like.

[0013] Furthermore, the present invention can be applied to the refrigeration needs of various gaseous and liquid working media including air.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] Innovatively combines liquid level measurement with solenoid valve control in the refrigeration cycle, replacing traditional throttling expansion valves and capillaries, regulating the gas-liquid composition relationship of the refrigerant between the condenser and the evaporator, and directly transporting the liquid refrigerant in the condenser to the evaporator without throttling. The evaporator always maintains sufficient liquid refrigerant for phase change vaporization. This solution can avoid the problem of insufficient refrigerant flow caused by the small opening of the expansion device in traditional throttling expansion. The liquid refrigerant entering the evaporator is directly sucked through the compressor inlet to form a significant low temperature and low pressure state, ensuring sufficient and controllable refrigerant flow and cooling capacity while achieving lower refrigeration temperature, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0017] Figure 1 This is a schematic diagram of a novel low-temperature refrigeration system based on solenoid valve liquid level control proposed by the present invention;

[0018] Reference numerals:

[0019] 1- compressor, 2- condenser, 3- liquid storage tank, 4- liquid level sensor, 5- controller, 6- solenoid valve, 7- evaporator, 8- input air. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0023] Embodiment 1, as Figure 1 As shown, a novel low-temperature refrigeration system based on solenoid valve liquid level control includes a compressor 1, a condenser 2, a liquid storage tank 3, a liquid level sensor 4, a controller 5, a solenoid valve 6, and an evaporator 7. For the flow pipeline of the refrigerant, the outlet of the compressor 1 is connected to the inlet of the condenser 2, the outlet of the condenser 2 is connected to the inlet of the liquid storage tank 3, the outlet of the liquid storage tank 3 is connected to the inlet of the solenoid valve 6, the outlet of the solenoid valve 6 is connected to the refrigerant inlet of the evaporator 7, and the refrigerant outlet of the evaporator 7 is connected to the inlet of the compressor 1.

[0024] The liquid level sensor 4 in the system is fixedly installed inside or on the outer surface of the liquid storage tank 3 according to actual working needs, and the height can be set according to actual needs. The liquid level sensor 4 is connected to the controller 5 and the solenoid valve 6 through a circuit. When the liquid level in the liquid storage tank 3 does not reach the set height, the liquid level sensor 4 is in an open circuit state, the system does not produce an action, and the refrigerant pipeline at the solenoid valve 6 is in a closed state. When the liquid level reaches the sensor set position, the refrigerant liquid pushes the float, lever and other mechanical structures of the liquid level sensor 4, so that the liquid level sensor 4 closes and outputs an electrical signal, so that the relay in the controller 5 is attracted, and then outputs a signal to the solenoid valve 6 to open it, so that the refrigerant passes. When the liquid level is lower than the set position, the liquid level sensor 4 is open again, the control signal is disconnected, and the solenoid valve 6 returns to the closed state, and then performs periodic repeated work.

[0025] During the refrigeration process of the system, the high-temperature and high-pressure refrigerant output by the compressor 1 is input into the condenser 2 for cooling and liquefaction, and then the refrigerant is input into the liquid storage tank 3. Initially, the liquid level does not reach the height of the liquid level sensor, and the solenoid valve 6 is closed. The liquid accumulates in the liquid storage tank 3, and the liquid level gradually rises, and the sensor float rises accordingly. When the liquid level reaches the position of the liquid level sensor 4, the float enters the detection range of the probe, the sensor closes and outputs an electrical signal, and the solenoid valve 6 is opened through the controller 5. The liquid refrigerant in the liquid storage tank 3 is discharged into the evaporator 7 in time, and the solenoid valve 6 is closed again after the liquid level drops back. Under the strong suction effect of the compressor 1, the liquid refrigerant is forced to expand and reduce pressure and temperature in the evaporator 7, and the input air 8 on the hot side is cooled by heat exchange. The refrigerant after absorbing heat and vaporization is input into the compressor 1 again, completing a refrigeration cycle.

[0026] In the embodiment of the present invention, the height position of the liquid level sensor 4 can be adjusted according to the actual system power and the refrigerant filling amount, and the drainage time after each power-on of the solenoid valve can also be set according to the needs. With the cooperation of the solenoid valve and the liquid level meter, the intermittent liquid replenishment of the evaporator 7 is realized. When the required evaporation amount in the evaporator 7 is large, the height of the liquid level meter can be appropriately lowered to shorten the on-off switching interval of the solenoid valve 6 and increase the frequency of liquid replenishment in the evaporator 7. Although the refrigerant flow in the evaporator 7 increases during the conduction period, the evaporation pressure rises, the evaporation temperature rises, and the refrigeration effect decreases. Therefore, the drainage time of each power-on of the solenoid valve 6 should not be too long and needs to be set flexibly.

[0027] In the embodiment of the present invention, the liquid level sensor 4 can adopt various working types such as but not limited to float type, buoy type, static pressure type, capacitance type, optical type, etc., and the actual selection can be flexibly selected according to the working conditions and the type of working fluid. When the liquid level in the liquid storage tank 3 changes, the liquid level sensor 4 forms a closed or open state due to the effect of the liquid level, outputs a high level or low level control signal to the controller end, and controls the on and off of the solenoid valve 6 through the logic circuit. In addition to automatic control through liquid level sensing, the controller 5 can also realize level output regulation through manual active control to improve the controllability of the system.

[0028] In the embodiments of the present invention, the present invention can be applied to the refrigeration requirements of various gaseous and liquid working media including air, water, etc.

[0029] In the embodiment of the present invention, the type of refrigerant can be flexibly selected according to the actual refrigeration temperature requirement range.

[0030] In the embodiments of the present invention, the pipelines involved have good pressure resistance and thermal insulation performance and can withstand long-term operation under high pressure and low and high temperature conditions.

[0031] Embodiment 2, as Figure 1 As shown, a novel low-temperature refrigeration system based on solenoid valve liquid level control includes a condenser 2, a compressor 1 and an evaporator 7. The system is also provided with:

[0032] A liquid storage tank 3, wherein the inlet of the liquid storage tank is connected to the outlet of the condenser, and the outlet of the liquid storage tank is connected to the inlet of the solenoid valve 6;

[0033] Solenoid valve 6, the outlet of the solenoid valve is connected to the refrigerant inlet of the evaporator;

[0034] A liquid level sensor 4, used to monitor the liquid level in the liquid storage tank;

[0035] The controller 5 is electrically connected to the liquid level sensor 4 and the solenoid valve 6 .

[0036] The high-temperature and high-pressure refrigerant output by the compressor 1 is liquefied by the condenser 2 and enters the liquid storage tank 3. When the liquid level sensor 4 detects that the liquid level reaches the set height, the controller 5 controls the solenoid valve 6 to open, so that the liquid refrigerant flows into the evaporator 7 for evaporation and cooling. The evaporated refrigerant enters the compressor 1 again to complete the refrigeration cycle.

[0037] In some embodiments, the liquid level sensor 4 is fixedly installed on the inner or outer surface of the liquid storage tank 3 .

[0038] In some embodiments, the controller 5 controls the switching state of the solenoid valve 6 according to the signal of the liquid level sensor 4 .

[0039] In some embodiments, the liquid level sensor 4 is connected to the controller 5 via a circuit to transmit liquid level information.

[0040] In some embodiments, the liquid level sensor 4 can be a float type, a buoy type, a static pressure type, a capacitive type or an optical type.

[0041] In some embodiments, the installation position of the liquid level sensor 4 can be adjusted according to the system power and the refrigerant filling amount.

[0042] In some embodiments, the signal output by the liquid level sensor 4 controls the switching state of the solenoid valve 6 .

[0043] In some embodiments, the single discharge duration of the solenoid valve 6 can be set by the controller 5 .

[0044] Furthermore, this embodiment uses R22 as the refrigerant, the volume of the liquid storage tank 3 is 2L, the installation position of the liquid level sensor 6 is the upper and lower end surfaces of the liquid storage tank 3, the type of the liquid level sensor 6 is capacitive, and its output signal is high potential, corresponding to the liquid level range of 0-10cm. The setting value of the controller 8 is equal to the output signal being high potential, corresponding to the liquid level of 5cm. When the signal of the liquid level sensor 6 is higher or lower than the setting value, the controller 8 controls the solenoid valve 6 to close or open respectively. The single discharge time of the solenoid valve 6 is 1s.

[0045] The working process of this implementation is as follows:

[0046] Start the compressor 1 to compress the low-temperature and low-pressure refrigerant vapor output from the evaporator 7 into high-temperature and high-pressure refrigerant vapor, and send it to the condenser 1 for cooling;

[0047] In the condenser 1, the high-temperature and high-pressure refrigerant vapor exchanges heat with the air, releasing heat to the environment, and condenses into liquid refrigerant, which flows into the liquid storage tank 3 for storage;

[0048] When the liquid level in the liquid storage tank 3 is lower than 5 cm, the signal output by the liquid level sensor 6 is at a high potential, which is equal to the set value of the controller 8. At this time, the solenoid valve 6 is in a closed state and does not deliver liquid refrigerant to the evaporator 7;

[0049] When the liquid level in the liquid storage tank 3 reaches 5 cm, the signal output by the liquid level sensor 6 is less than 2.5 V. The controller 8 detects the signal change and controls the solenoid valve 6 to open to deliver liquid refrigerant to the evaporator 7. The solenoid valve 6 is opened for 1 second each time.

[0050] In the evaporator 7, the liquid refrigerant exchanges heat with the input air, transferring the heat absorbed by the refrigerant to the input air, and at the same time evaporates into low-temperature and low-pressure refrigerant vapor, which flows back to the compressor 1 for recompression, completing the refrigeration cycle;

[0051] When the liquid level in the liquid storage tank 3 is lower than 5 cm, the signal output by the liquid level sensor 6 is at a low potential. The controller 8 detects the signal change and controls the solenoid valve 6 to close, stopping the supply of liquid refrigerant to the evaporator 7 until the liquid level is lower than 5 cm again, and repeats the above steps.

[0052] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0053] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A new low-temperature refrigeration system based on solenoid valve liquid level control, including a condenser, a compressor and an evaporator, characterized in that: The system also has: A liquid storage tank, wherein an inlet of the liquid storage tank is connected to an outlet of the condenser, and an outlet of the liquid storage tank is connected to an inlet of the solenoid valve; Solenoid valve, the outlet of the solenoid valve is connected to the refrigerant inlet of the evaporator; Liquid level sensor, used to monitor the liquid level in the storage tank; The controller is electrically connected to the controller and the solenoid valve.

2. A novel low-temperature refrigeration system based on solenoid valve liquid level control according to claim 1, characterized in that: The liquid level sensor is fixedly installed inside or on the outer surface of the liquid storage tank.

3. A novel low-temperature refrigeration system based on solenoid valve liquid level control according to claim 1, characterized in that: The controller controls the switch state of the solenoid valve according to the signal of the liquid level sensor.

4. A novel low-temperature refrigeration system based on solenoid valve liquid level control according to claim 1, characterized in that: The liquid level sensor is connected to the controller via a circuit to transmit liquid level information.

5. A novel low-temperature refrigeration system based on solenoid valve liquid level control according to claim 1, characterized in that: The liquid level sensor is one of a float type, a buoy type, a static pressure type, a capacitance type or an optical type.

6. A novel low-temperature refrigeration system based on solenoid valve liquid level control according to claim 1, characterized in that: The installation position of the liquid level sensor is adjusted according to the system power and the refrigerant filling amount.

7. A novel low-temperature refrigeration system based on solenoid valve liquid level control according to claim 1, characterized in that: The switching state of the solenoid valve is controlled by the signal output by the liquid level sensor.

8. A novel low-temperature refrigeration system based on solenoid valve liquid level control according to claim 1, characterized in that: The single discharge duration of the solenoid valve is set by a controller.

9. A novel low-temperature refrigeration system based on solenoid valve liquid level control according to claim 1, characterized in that: The high-temperature and high-pressure refrigerant output by the compressor is liquefied by the condenser and then enters the liquid storage tank. When the liquid level sensor detects that the liquid level has reached the set height, the controller controls the solenoid valve to open, allowing the liquid refrigerant to flow into the evaporator for evaporation and cooling. The evaporated refrigerant enters the compressor again to complete the refrigeration cycle.

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