A compressor lubricating oil cooling system and its control method

Abstract

The invention discloses a lubricating oil cooling system for a compressor, which is characterized in that it comprises a compressor, an oil separator, a condenser, a liquid reservoir, a shut-off valve for the outlet of the liquid reservoir, a dry filter, and a solenoid valve connected in sequence through pipelines. , electronic expansion valve and plate heat exchanger; the lubricating oil outlet of the plate heat exchanger communicates with the compressor through the oil supply pipe; the oil supply pipe is provided with a temperature sensor for measuring the return temperature of the lubricating oil; the temperature sensor is controlled in series The device and the electronic expansion valve driver are electrically connected to the electronic expansion valve; the temperature sensor is electrically connected to the solenoid valve through a series temperature switch. The invention also discloses a control method of the lubricating oil cooling system of the compressor. The invention can keep the oil return temperature of lubricating oil stable, reduce the failure rate of the compressor, and improve the service life of the plate heat exchanger at the same time.

Description

technical field [0001] The invention relates to the refrigeration field, in particular to a compressor lubricating oil cooling system and a control method thereof. Background technique [0002] At present, in refrigeration units used in the refrigeration industry, the high-temperature lubricating oil separated by the oil separator after the compressor is exhausted is mostly used to throttle the condensed liquid refrigerant and directly evaporate and exchange heat in the plate heat exchanger. cooling method. The cooled lubricating oil flows back into the compressor to lubricate and cool moving parts such as bearings. The traditional lubricating oil cooling system mostly uses devices such as thermal expansion valves or orifice plates to throttle the liquid refrigerant, and the thermostat controls the start and stop of the liquid supply solenoid valve according to the temperature of the lubricating oil after cooling. [0003] The Chinese patent application number 201110276326...

AI Technical Summary

Problems solved by technology

When the external environment temperature changes, the oil cooling load changes greatly, and the cooling capacity of the system for lubricating oil also changes greatly, which makes it difficult to keep the lubricating oil return temperature stable within the specified range

[0005] The traditional control method has the following defects when the system is working: due to the influence of the external environment and the operating load of the system, the cooling load of the lubricating oil is constantly changing, and it is difficult to select a throttling device with a suitable specification to stabilize the return temperature of the lubricating oil within the specified range

Excessively high lubricating oil return temperature will reduce its viscosity and reduce the lubricity of the moving parts of the compressor. Excessively high lubricating oil return temperature will also lead to excessively high discharge temperature of the compressor, which may cause the compressor to malfunction

Too low lubricating oil return temperature will make its fluidity worse, it is not easy to form an oil film between the rotors, and reduce the sealing performance of the compressor

At the same time, when the load required for lubricating oil cooling is low, too much refrigerant liquid supply will cause insufficient evaporation and vaporization of the refrigerant in the plate heat exchanger, and a large amount of liquid refrigerant will flow back into the compressor, which may cause the compressor to be damaged by liquid. impact, but also reduces the volumetric efficiency of the compressor

In order to maintain the return temperature of the lubricating oil within an appropriate range, the liquid supply solenoid valve will be frequently started and stopped, and the large change in the evaporation of the refrigerant in the plate heat exchanger will cause the plate temperature to fluctuate continuously, which will easily cause thermal fatigue and cracks on the plate , causing a leak

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