Control method for preventing multi-unit air conditioner screw compressor from liquid impact

Abstract

The invention discloses a control method for preventing a multi-unit air conditioner screw compressor from liquid impact. The method comprises the following steps of: (1) closing each electromagnetic valve and closing an electronic expansion valve of each indoor unit when an air conditioning unit is electrified and stands by; (2) when oil temperature of an oil sump reaches a set oil temperature, opening a master liquid supply electromagnetic valve, opening a liquid supply electromagnetic valve on a liquid supply pipe of an indoor unit which receives a power-on instruction, opening the electronic expansion valve of the indoor unit, and loading the screw compressor in a gradient way until the screw compressor is fully loaded; (3) opening an electromagnetic valve on a gas-liquid separator oil return pipe when the total load of the indoor unit is in a partial load condition; (4) closing a liquid supply electromagnetic valve and the electronic expansion valve on the corresponding liquid supply pipe when a certain indoor unit is stopped; and (5) when the indoor unit is stopped, closing the master liquid supply electromagnetic valve, closing the electromagnetic valves and the electronic expansion valves on the liquid supply pipes of all the indoor units, and then stopping the screw compressor. Compared with the conventional method, the method has the characteristic of avoiding liquidimpact phenomenon, along with high operation stability and safety.

Description

technical field [0001] The invention relates to the field of air conditioner control, in particular to a control method for preventing liquid hammering of multi-connected air conditioner screw compressors. Background technique [0002] The multi-connected air conditioner in the prior art refers to the use of basic modules with different capabilities, which are combined into outdoor units (8HP to 64HP) with different capabilities according to the load of the air-conditioned room, or a small number of outdoor units tow multiple indoor units. machine. The former is a large-scale commercial application, and the latter is a household application. This type of multi-connected air conditioner indoor unit is equipped with an electronic expansion valve for throttling. In the cooling mode, when the indoor unit is shut down due to a fault or the indoor ambient temperature reaches high temperature, the electronic expansion valve opening of the indoor unit that was previously opened wil...

AI Technical Summary

Problems solved by technology

Therefore, when the air-conditioning system is shut down for a long time during non-working hours, and the indoor electronic expansion valve is open, the pressure on the high-pressure side and low-pressure side of the air-conditioning system will be balanced, making the refrigerant filled with the high-pressure side and low-pressure side, and making the original high-pressure side The liquid refrigerant enters the low-pressure side; when it is necessary to start the machine, because there is a large amount of liquid refrigerant on the low-pressure side, it will inevitably cause a large amount of liquid refrigerant to enter the compression chamber through the return pipe, forming liquid compression, which makes the refrigerant in the lubricating oil boil, and the lubricating oil The oil is brought into the compression chamber to produce oil pressure hydraulic shock, that is, liquid shock phenomenon, which will damage the compressor rotor and eventually lead to the paralysis of the air conditioning system, so the operation stability and safety are poor

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