Safety control method for lubricating oil of multi-unit air conditioner of screw compressor

Abstract

The invention discloses a safety control method for lubricating oil of a multi-unit air conditioner of a screw compressor. The method comprises the following steps of: (1) electrifying an air conditioning unit; (2) starting the screw compressor when oil temperature of an oil sump reaches a certain value; (3) opening an oil return electromagnetic valve to replenish the oil if the oil level in the oil sump of the screw compressor is lower than a safety oil level; (4) loading in a gradient way until full load is realized when the screw compressor is started; (5) opening the oil return electromagnetic valve to replenish the oil when the oil level of the oil sump during running is lower than the safety oil level, and opening a gas separation oil return electromagnetic valve to return the oil if the load of the screw compressor is less than 20-55 percent; and (6) unloading in a gradient way until the screw compressor is stopped when the screw compressor reaches stoppage conditions. Compared with the conventional method, the method has the characteristic of guaranteeing that the oil level of the lubricating oil in the oil sump of the screw compressor is positioned above the safety oil level in a starting process, an automatic adjustment process, a stoppage process and a protective adjustment process or the time for keeping the oil level below the safety oil level does not exceed 3 minutes.

Description

technical field [0001] The invention relates to the field of air-conditioning control, in particular to a safety control method for multi-connected air-conditioning lubricating oil of screw compressors. Background technique [0002] At present, when screw compressors are used in conventional screw compressor air conditioners such as air-cooled chillers or water-cooled chillers, all components of the refrigeration cycle in the outdoor unit, such as screw compressors, oil-gas separators, and heat exchangers (shells) Tube evaporator, shell-and-tube condenser or air-cooled condenser), throttling components and connecting pipeline parts, etc., are assembled in the outdoor unit to form a whole. Therefore, the screw compressor is in the process of startup or automatic control operation In the process, the lubricating oil can be returned to the compressor smoothly, and no other special considerations are required to ensure the safety of the lubricating oil of the screw compressor. ...

AI Technical Summary

Problems solved by technology

However, when the screw compressor is applied to a screw compressor multi-connected air conditioner, since one outdoor unit has to drag multiple or even more than 100 indoor units, and the distance between the indoor unit and the outdoor unit will reach more than 100 meters, at this time , a large amount of lubricating oil will be retained in the indoor evaporator and in the system pipeline, so the multi-connected air-conditioning lubricating oil safety control method in the prior art cannot solve the problem in the starting process, automatic adjustment process, shutdown process and protective adjustment process. , it must be ensured that the lubricating oil level in the screw compressor oil pool is above the safe oil level, or the oil level is below the safe oil level for no more than 3 minutes

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