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Principle and operation of nitrogen compressor
- 2018-08-10-

Nitrogen compressors are mainly used in various industrial requirements. Pipes are connected between the original inlet of the nitrogen compressor and the balance gas tank. When the sealing performance of the seal is not very good, the pipeline provides a certain pressure. Prevents air from leaking into the cylinder from the gap between the seal and the piston rod, thus ensuring the purity of the compressed nitrogen. Through the improved compressor conditions, the compressor has been greatly improved. Let us explain the nitrogen compressor. principle.

The control system of the nitrogen compressor is generally relatively simple. In some compressors with earlier years, the motor used is mostly a wound motor, and the starting mode is started by a frequency sensitive varistor. In recent years, it has basically been changed to use squirrel cage motors, many of which use direct start mode. The starting current of this starting mode is too large, there is a great safety hazard, which brings many disadvantages in terms of safety and operation. In order to improve these problems, we changed the control system of the motor to the star-delta startup mode to reduce the starting current, and added chain and alarm functions to the entire control system, mainly for the fuel supply system and water supply system of the equipment. Chain and alarm functions, and alarm function is set for both the three-stage exhaust temperature and the exhaust pressure.

Nitrogen compressor operation

After the nitrogen compressor was turned on, the gas supply operation was not carried out after careful inspection. After half an hour, the exhaust temperature of the DCS exceeded the temperature alarm. When the site was inspected, it was found that the total inlet and return valve of the machine was not opened, and the cylinder returned to the sight glass burst. Stop immediately, then be careful not to forcibly supply water to prevent other accidents from sudden temperature drop. After the nitrogen compressor was started for more than two hours, the first-stage exhaust temperature exceeded 180 °C interlocking shutdown (normal operating temperature 155 °C). After investigation, the two DN25 return valves of the primary cylinder and the second- and third-class cylinders were not opened. Caused. When the machine was overhauled the day before yesterday, the two valves were closed, the inspection was not resumed, and the valve was not carefully checked before starting, resulting in insufficient cylinder cooling and excessive exhaust gas temperature.

When the nitrogen compressor is turned on, the hand gear oil pump supplies oil to the lubrication points of the crankcase. After the pump pressure gauge rises, the hand crank is stopped. At this time, the oil pressure before entering the crankcase on the DCS does not rise. After starting the machine, the crankcase breathing hole and the scraper are white smoke, and the machine is stopped quickly. The crankcase side cover is opened, and the hand pump is used to check the smooth flow of each lubrication flow path. Read the trend chart on the DCS: After 30 seconds of power on, the oil pressure appears on the DCS, and it stops after 2 minutes of operation. Since there is no oil in the first 30s, the original residual oil is vaporized.

The interstage cooler of the oxygen-nitrogen press, the water pipe, the gas shell, the heat exchange effect caused by the blockage of the copper heat exchange tube, the mechanical method is used to dredge the heat exchange tube, and this method is used for a long time, resulting in the heat exchange tube Missing. During operation, the second and third stage exhaust pressures are greater than the water pressure, and bubbles appear in the returning plexiglass mirror of the second and third stage coolers to determine the cooler leakage. By disassembling the ends of the two ends, the self-made flange is installed, and the air is leaked, and the heat exchange tube is leaked, and the plug is blocked by the plug. At present, three heat exchangers have been blocked by copper pipes. The sealing between the tube plate of the cooler and the casing is sealed by a packing, and the sealing is not strict, and the leakage is replaced. The replacement of the new packing or the proper fastening of the head bolt can eliminate the leakage.