A high temperature air conditioning anti-freezing control system

Abstract

The present invention discloses a high-temperature air conditioner anti-freezing control system, which is used for a refrigeration circuit composed of a compressor, a condenser, a liquid storage device, a filter, an expansion valve, and an evaporator, and includes an ice point protector, a high-pressure pressure controller, a low-pressure pressure controller, an AC contactor of the compressor, and a time relay. The temperature sensing probe of the ice point protector measures the temperature of the evaporator coil. The high and low pressure controllers are respectively installed at the exhaust end and the return end of the compressor. The contacts of the high and low pressure controllers, the power-on delay closing contacts of the time relay, and the AC contactor coil of the compressor are connected in series in sequence to form a first series branch. The two ends of the first series branch are respectively connected to an external power supply. The coil of the time relay and the contact of the ice point protector are connected in series to form a second series branch. The second series branch is connected in parallel with the power-on delay closing contacts and the AC contactor coil of the compressor. The present invention enables the high-temperature air conditioner to operate at a low-temperature refrigeration, and realizes a high-low temperature integrated machine.

Description

Technical Field

[0001] The invention relates to the field of high-temperature air-conditioning systems, in particular to a high-temperature air-conditioning anti-freezing control system. Background Art

[0002] Vehicle-mounted and airborne transport equipment that performs tasks such as transportation, communication, and detection, as well as equipment rooms in industries, power plants, and oil drilling platforms, usually work in high-temperature environments and require special high-temperature air conditioners that are adapted to their working environments to control their temperatures. However, for some machine rooms, electronic cabins of transport equipment, laser devices, etc., when the ambient temperature (usually below 18°C) is low, the heating elements in the cabins being cooled have a large amount of heat and still require air conditioning to cool the machine rooms and cabins. Conventional high-temperature air conditioning products can be adjusted through a liquid storage tank when working at room temperature, but if they continue to cool when the ambient temperature is low, it will cause frost and ice on the evaporator, and even cause "liquid hammer" damage to the compressor, affecting the normal use of the unit.

[0003] Therefore, when the high-temperature air conditioner is operating in low-temperature refrigeration mode, that is, the high-temperature air conditioner can work reliably under low-temperature refrigeration conditions, a reliable refrigeration system must be designed and corresponding control measures must be taken. Summary of the invention The purpose of the present invention is to provide a high temperature air conditioning anti-freezing control system to solve the problem of "liquid hammer" damage to the compressor when the high temperature air conditioning system in the prior art is running.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A high-temperature air conditioner anti-freezing control system is used for a closed-cycle refrigeration circuit composed of a compressor, a condenser, a liquid storage device, a filter, an expansion valve, and an evaporator. The invention is characterized in that the invention comprises an ice point protector, a high-pressure pressure controller, a low-pressure pressure controller, an AC contactor of the compressor, and a time relay, wherein the temperature sensing probe of the ice point protector contacts the coil of the evaporator to measure the temperature of the evaporator coil, the high-pressure pressure controller is installed in the compressor exhaust end pipeline, the low-pressure pressure controller is installed in the compressor return end pipeline, the contacts of the high-pressure pressure controller, the contacts of the low-pressure pressure controller, the power-on delay closing contacts of the time relay, and the AC contactor coil of the compressor are connected in series in sequence to form a first series branch, the power-on delay closing contacts of the time relay and the AC contactor coil of the compressor in the first series branch form a compressor control section, the two ends of the first series branch are respectively connected to external power supplies, the coil of the time relay and the contacts of the ice point protector are connected in series to form a second series branch, and the second series branch is connected in parallel with the compressor control section in the first series branch.

[0006] The high-temperature air-conditioning anti-freeze control system is characterized by: a closed-cycle refrigeration circuit, the exhaust end of the compressor is connected to the inlet end of the condenser through a pipeline, the outlet end of the condenser is connected to the inside of the liquid reservoir through a pipeline, the inside of the liquid reservoir is also connected to the inlet end of the filter through a pipeline, the outlet end of the filter is connected to the inlet end of the expansion valve through a pipeline, the outlet end of the expansion valve is connected to the inlet end of the evaporator through a pipeline, and the outlet end of the evaporator is connected to the return air end of the compressor through a pipeline, thereby forming a closed-cycle refrigeration circuit.

[0007] The high-temperature air-conditioning anti-freezing control system is characterized in that R134a high-temperature environmentally friendly refrigerant circulates in the closed-cycle refrigeration circuit.

[0008] The high-temperature air-conditioning anti-freeze control system is characterized in that the coil of the evaporator is equipped with a temperature-sensitive copper sleeve, the wall of the temperature-sensitive copper sleeve is welded to the coil wall of the evaporator, and the temperature-sensitive probe of the freezing point protector is inserted into the temperature-sensitive copper sleeve from the pipe mouth of the temperature-sensitive copper sleeve.

[0009] The present invention adopts a method of installing a liquid storage tank at the outlet of the condenser to improve the applicability of the system; a temperature-sensitive copper sleeve is welded on the evaporator coil, and an ice point protector temperature-sensitive probe is inserted to sense the temperature of the evaporator coil. The start and stop of the compressor are controlled through the ice point protector contact, so that the frost (ice) on the evaporator can be melted in time to prevent the compressor from being damaged by "liquid hammer", and the delay contact of the time relay is used to ensure that the compressor has an interval of more than 3 minutes before starting again.

[0010] The beneficial effects of the present invention are:

[0011] 1. By designing a reliable refrigeration system and taking appropriate control measures, high-temperature air conditioners can operate at low-temperature refrigeration, realizing a high-low temperature integrated machine.

[0012] 2. Install a liquid storage tank at the outlet of the condenser of the air conditioning refrigeration system; weld a temperature-sensitive copper sleeve on the evaporator coil, insert the freezing point protector temperature probe, sense the temperature of the evaporator coil, control the start and stop of the compressor through the freezing point protector contact, and ensure that the compressor has an interval of more than 3 minutes to start again through the power-on delay closing contact of the time relay. This effectively solves the problem that the high-temperature air conditioning refrigeration system continues to refrigerate when the ambient temperature is low, which will cause frost and ice on the evaporator, until the compressor is damaged by "liquid strike", affecting the normal operation of the unit.

[0013] 3. The present invention has a simple structure, low failure rate, safety and reliability, and low cost, and therefore is economical and practical.

[0014] 4. The present invention improves the adaptability of refrigeration systems with large temperature changes and large load changes through optimized matching of the refrigeration system and effective control measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a system structure diagram of the present invention.

[0016] Figure 2 It is the principle diagram of the electrical part of the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0018] like Figure 1 As shown, a high-temperature air-conditioning anti-freezing control system is used for a closed-cycle refrigeration circuit consisting of a compressor 1, an evaporator 3 with an evaporating fan 2, an expansion valve 4, a filter 5, a liquid reservoir 6, and a condenser 7 with a condensing fan 9. In the closed-cycle refrigeration system, the exhaust end of the compressor 1 is connected to the inlet end of the condenser 7 through a copper tube, the outlet end of the condenser 7 is connected to the inside of the liquid reservoir 6 through a copper tube, the inside of the liquid reservoir 6 is also connected to the inlet end of the filter 5 through a copper tube, the outlet end of the filter 5 is connected to the inlet end of the expansion valve 4 through a copper tube, the outlet end of the expansion valve 4 is connected to the inlet end of the evaporator 3 through a copper tube, and the outlet end of the evaporator 3 is connected to the return air end of the compressor 1 through a copper tube, thereby forming a closed-cycle refrigeration circuit, in which R134a high-temperature environmentally friendly refrigerant flows.

[0019] The control system of the present invention includes an AC contactor KM 12, a time relay KT 13, an ice point protector ST 8, a high pressure controller 11, and a low pressure controller 10 of a compressor 1. A temperature-sensitive copper sleeve is welded on the coil of the evaporator 3, and a temperature-sensitive probe of the ice point protector ST8 is inserted into the temperature-sensitive copper sleeve; the low pressure controller 10 is inserted into the copper tube at the return air end of the compressor 1, and the high pressure controller 11 is inserted into the copper tube at the exhaust end of the compressor 1, and is welded to the system with a brazing rod containing 15% silver.

[0020] The contact 11-1 of the high-pressure pressure controller 11, the contact 10-1 of the low-pressure pressure controller 10, the power-on delayed closing contact KT-1 of the time relay KT 13 and the coil KM-1 of the AC contactor KM 12 of the compressor 1 are connected in series in sequence to form a first series branch, and the two ends of the first series branch are respectively connected to the live wire L and the neutral wire N of the external power supply. The contact ST-1 of the freezing point protector ST 8 and the coil KT-2 of the time relay KT 13 are connected in series to form a second series branch, and the second series branch is connected in parallel to the series part of the power-on delayed closing contact KT-1 of the time relay KT 13 and the coil KM-1 of the AC contactor KM 12 of the compressor 1.

[0021] A liquid accumulator 6 is installed at the outlet of the condenser 7 of the present invention. When the heat load is reduced or the ambient temperature is low, the refrigerant cannot be completely evaporated in the evaporator 3, which will cause excess refrigerant in the air conditioning refrigeration system at low temperatures. In this way, refrigerant liquid and refrigerant gas may mix and enter the compressor 1. Therefore, a liquid accumulator 6 should be installed before entering the evaporator 3 to store liquid refrigerant to prevent liquid refrigerant from entering the suction chamber of the compressor 1 and breaking through the suction valve plate, i.e. "liquid shock", which may cause damage to the compressor 1. Therefore, adding a liquid accumulator 6 to the refrigeration system can ensure that a certain amount of refrigerant can be stored when the refrigeration conditions change drastically, thereby stabilizing the system pressure. Therefore, for systems with wide temperature changes and load changes, the provision of a liquid accumulator 6 can improve the adaptability of the refrigeration system.

[0022] A temperature-sensitive copper sleeve is welded on the evaporator 3 coil, and the temperature sensor of the freezing point protector ST 8 is inserted to sense the temperature of the evaporator coil, and a suitable action temperature value is set for the freezing point protector (set to -2℃, contact open, hysteresis 8℃, contact closed). The start and stop of compressor 1 is controlled by contact ST-1 of freezing point protector ST 8, and contact KT-1 is closed by power-on delay of time relay KT 13 to control AC contactor KM 12 of compressor 1, ensuring that there is an interval of more than 3 minutes before compressor 1 starts again. When the temperature probe of the freezing point protector ST 8 senses the evaporator coil temperature of -2℃, the contact ST-1 of the freezing point protector ST 8 is disconnected, the coil KT-2 of the time relay KT 13 loses power, the power-on delay closing contact KT-1 on the time relay KT 13 is instantly disconnected, the coil KM-1 of the AC contactor KM 12 of the compressor 1 loses power, the compressor 1 stops working, and the frost (ice) on the coil and fins of the evaporator 3 gradually melts away. When the temperature probe of the freezing point protector ST 8 senses that the evaporator 3 coil temperature reaches 6℃, the contact ST-1 of the freezing point protector ST 8 is closed, the coil KM-1 of the time relay KT 13 is energized, the power-on delay closing contact KT-1 of the time relay KT 13 is closed after a delay of 3 minutes, the coil KM-1 of the AC contactor KM 12 of the compressor 1 is energized, the compressor 1 starts, and the refrigeration system operates normally. Therefore, the temperature of the evaporator coil is sensed by the temperature sensor of the freezing point protector ST 8 to control the start and stop of the compressor 1, ensuring the normal defrosting of the system and avoiding "liquid hammer" and damage to the compressor.

[0023] When the air conditioner works in a low temperature environment, the system pressure will decrease, or the system refrigerant will leak, damaging the compressor 1. In order to prevent the refrigeration system pressure from being too low, a low-pressure pressure controller 10 is set. When the system pressure is lower than the set value of the low-pressure pressure controller 10, the compressor 1 is stopped.

[0024] When the air conditioner works in a high temperature and harsh environment, the system pressure will increase. In order to prevent the refrigeration system pressure from being too high and damaging the compressor 1, a high-pressure pressure controller 11 is set. When the system pressure exceeds the set value of the high-pressure pressure controller 11, the compressor 1 is stopped.

[0025] The above embodiments are not limited to the protection scope of the present invention, and all modifications or changes based on the basic concept of the present invention belong to the protection scope of the present invention.

[0026] The embodiments described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have all been recorded in the claims.

Claims

1. A high temperature air conditioner anti-freezing control system, used in a closed cycle refrigeration circuit consisting of a compressor, a condenser, a liquid storage device, a filter, an expansion valve, and an evaporator, characterized in that: It includes an ice point protector, a high-pressure pressure controller, a low-pressure pressure controller, an AC contactor of a compressor, and a time relay, wherein the temperature sensing probe of the ice point protector contacts the coil of the evaporator to measure the temperature of the evaporator coil, the high-pressure pressure controller is installed on the exhaust end pipeline of the compressor, and the low-pressure pressure controller is installed on the return end pipeline of the compressor, the contacts of the high-pressure pressure controller, the contacts of the low-pressure pressure controller, the power-on delay closing contacts of the time relay, and the AC contactor coil of the compressor are connected in series in sequence to form a first series branch, the power-on delay closing contacts of the time relay and the AC contactor coil of the compressor in the first series branch form a compressor control section, the two ends of the first series branch are respectively connected to external power supplies, the coil of the time relay and the contacts of the ice point protector are connected in series to form a second series branch, and the second series branch is connected in parallel with the compressor control section in the first series branch; R134a high-temperature environmentally friendly refrigerant circulates in the closed-cycle refrigeration circuit; The coil of the evaporator is equipped with a temperature-sensitive copper sleeve, the wall of the temperature-sensitive copper sleeve is welded to the coil wall of the evaporator, and the temperature-sensitive probe of the freezing point protector is inserted into the temperature-sensitive copper sleeve from the pipe mouth of the temperature-sensitive copper sleeve.

2. A high temperature air conditioning anti-freezing control system according to claim 1, characterized in that: A closed cycle refrigeration circuit, the exhaust end of the compressor is connected to the inlet end of the condenser through a pipeline, the outlet end of the condenser is connected to the inside of the liquid reservoir through a pipeline, the inside of the liquid reservoir is also connected to the inlet end of the filter through a pipeline, the outlet end of the filter is connected to the inlet end of the expansion valve through a pipeline, the outlet end of the expansion valve is connected to the inlet end of the evaporator through a pipeline, and the outlet end of the evaporator is connected to the return air end of the compressor through a pipeline, thus forming a closed cycle refrigeration circuit.

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