What is the working principle of the screw air compressor oil circuit system?

Update:01-06-2022

Summary:The oil circuit system of Rotary screw air compressor includes oil tank, oil cooler, oil filter, oil cut-off valve, temperature control valve, etc. Th...

The oil circuit system of Rotary screw air compressor includes oil tank, oil cooler, oil filter, oil cut-off valve, temperature control valve, etc.

The lower volume of the oil and gas separator acts as a fuel tank, and is equipped with a fuel hole, a drain plug and an oil level gauge.

The conventional screw air compressor does not have a hydraulic pump, and the circulation of the lubricating oil is realized by the pressure difference between the pressure before the filter element and the oil injection port of the main engine. When the compressor is running, the gas in the oil-air separator first builds up pressure under the action of the minimum pressure valve, forcing the lubricating oil to pass through the oil cooler, and then through the oil filter to enter the oil shut-off valve, and inject oil to the upper and lower parts of the main engine. Oil is supplied to the hole to take away the heat generated by the air during the compression process, and at the same time lubricate and seal the working chamber of the main engine to reduce internal leakage.

After the atomized oil injected into the compressor is mixed with air and compressed, it re-enters the oil-gas separator through the exhaust one-way valve.

1. Oil cooler

The cooling method of the oil cooler and the air cooler is the same, and there are two cooling methods: air cooling and water cooling. If the environmental conditions are not good, the fins of the air-cooled cooler are easily covered by dust and affect the cooling effect. Therefore, the dust on the surface of the fins should be blown off regularly with low-pressure air; if it cannot be blown clean, it must be cleaned with a solvent, and the cooling surface of the cooler must be kept clean.

When the pipe of the water-cooled cooler is blocked, it must be soaked with solvent, and the scale blocked in the pipe must be removed mechanically to ensure complete cleaning.

2. Oil filter

The oil filter equipped with differential pressure transmitter, its function is to remove impurities in the oil and keep the lubricating oil clean, so as to protect the operation of the air compressor main engine. If the filter is blocked, it will cause insufficient oil supply to the main engine, which will increase the temperature of the oil and gas, thus affecting the life of the moving parts of the main engine.

When the oil filter is blocked, the differential pressure transmitter will give an indication and the signal light will be on. It should be stopped in time for inspection or replacement. Whether to replace the filter element should be determined according to the actual situation.

3. Cut-off valve

The oil shut-off valve is mainly composed of valve body, valve core, floating plug, spring and other components. The oil shut-off valve is one of the important components in the compressor. Its working principle is: immediately after starting up, the high-pressure chamber of the main engine supplies air to the end of the oil shut-off valve, and the piston overcomes the spring pressure and pushes the floating plug to open the oil shut-off valve. spool to start supplying oil.

When the unit is running, the oil shut-off valve is always open; after the unit is shut down, the oil shut-off valve should be closed in time to prevent oil from flooding into the main engine.

4. Thermostatic valve

Water-cooled compressors are equipped with temperature control valves at the oil inlet of the cooler. Its function is to control the bypass flow of lubricating oil through the cooler to ensure that the oil and gas temperature of the compressor is higher than the pressure dew point temperature when the compressor is running under load. Because the lower fuel injection temperature will make the oil and gas temperature of the main engine too low, condensed water will be precipitated in the oil and gas separator and cooler, and it will not be easily taken out by the gas system, thereby deteriorating the quality of the lubricating oil and shortening its service life.

The working principle of the temperature control valve is: at the beginning, the lubricating oil temperature is low, and the lubricating oil bypass directly enters the main engine through the oil filter and the oil shut-off valve; if the oil and gas temperature rises to 71 degrees, the temperature sensing element in the temperature control valve extends. long, push the valve core to move in the valve body; start to close the bypass channel, gradually open the channel leading to the oil cooler, the ratio of the flow area of the two channels is determined by the oil and gas temperature; when the oil and gas temperature rises to 75 degrees, The bypass port is closed, and all the lubricating oil flows to the oil cooler for cooling cycle.
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