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Operation of screw refrigeration compressor

1.First start and stop

Before starting up, the coupling must be realigned. When starting up for the first time, you must first check the working conditions of all parts of the compressor and electrical components.

The inspection items are as follows:

  a. Close the power switch and select the manual position of the selector switch;
  b. Press the alarm button, the alarm bell will sound; press the silence button, the alarm will be eliminated;
  c, Press the electric heating button and the indicator light is on. After confirming that the electric heater is working, press the heating stop button and the heating indicator light is off;
  d. Press the water pump start button, the water pump starts, the indicator light is on, press the water pump stop button, the water pump stops, and the indicator light is off;
  e. Press the start button of the oil pump, the indicator light of the oil pump is on, the oil pump is running and rotating in the correct direction, and the oil pressure difference is adjusted to 0.4~0.6MPa. Flip the four-way valve or press the load increase/decrease button to check whether the slide valve and the energy indicating device are working normally, and the final energy level indicator is at the “0″ position.

Check the set value of each automatic safety protection relay or program/compressor temperature and pressure protection reference value:

  a. High exhaust pressure protection: exhaust pressure≦1.57MPa
  b. High fuel injection temperature protection: fuel injection temperature≦65℃
  c. Low oil pressure difference protection: oil pressure difference ≧0.1MPa
  d. High pressure difference protection before and after the fine filter: pressure difference≦0.1MPa
  e. Low suction pressure protection: set according to actual working conditions

2021.11.22After checking the above items, it can be turned on

The steps to turn on are as follows:

  a. The selector switch is manually turned on;
  b. Open the compressor discharge shut-off valve;
  c. Unload the compressor to the “0″ position, which is the 10% load position;
  d. Start the cooling water pump and the refrigerant water pump to supply water to the condenser, oil cooler and evaporator;
  e. Start the oil pump;
  f. 30 seconds after the oil pump is started, the difference between the oil pressure and the discharge pressure reaches 0.4~0.6MPa, press the compressor start button, the compressor starts, and the bypass solenoid valve A also opens automatically. After the motor runs normally, the A valve is automatically closed;
 g. Observe the suction pressure gauge, gradually open the suction stop valve and manually increase the load, and pay attention to the suction pressure not to be too low. After the compressor enters normal operation, adjust the oil pressure regulating valve so that the oil pressure difference is 0.15~0.3MPa.
  h. Check whether the pressure and temperature of each part of the equipment, especially the temperature of the moving parts, are normal. If there is any abnormality, stop the machine for inspection.
  i. The initial operation time should not be too long, and the machine can be shut down in about half an hour. The shutdown sequence is unloading, stopping the host, closing the suction shut-off valve, stopping the oil pump, and stopping the water pump to complete the first start-up process. When the main engine stop button is pressed, the bypass solenoid valve B is automatically opened, and the valve B is automatically closed after shutdown.

 

2.Normal startup and shutdown

The normal startup are as follows:

Select manual boot, the process is the same as the first boot.
Select automatic power-on:

  1) Open the compressor exhaust shut-off valve, start the cooling water pump and the refrigerant water pump;

  2) Press the compressor start button, then the oil pump will be automatically put into operation, and the spool valve will automatically return to the “0″ position. After the oil pressure difference is established, the main motor will start automatically after a delay of about 15 seconds, and the bypass solenoid valve A will automatically open at the same time. After the motor runs normally, the A valve is automatically closed;

  3) When the main motor starts to start, the suction shut-off valve should be opened slowly at the same time, otherwise the excessively high vacuum will increase the vibration and noise of the machine.

  4) The compressor will automatically increase the load to 100% and enter the normal working state. And automatically adjust the load position according to the pressure setting value or the refrigerant temperature setting value.

The normal shutdown process are as follows:

Manual shutdown is the same as the shutdown process of the first startup.
The selector switch is in the automatic position:

   1) Press the compressor stop button, the slide valve will automatically return to the “0″ position, the main motor will automatically stop, and the bypass solenoid valve B will automatically open at the same time, the oil pump will automatically stop after a delay, and the B valve will automatically close after stopping;

   2) Close the suction stop valve. If it is shut down for a long time, the exhaust shut-off valve should also be closed;

   3) Turn off the power switch of the water pump and the compressor.

3. Precautions during operation

   1) Pay attention to observe the suction and discharge pressure, suction and discharge temperature, oil temperature and oil pressure during compressor operation, and record regularly. The meter is required to be accurate.

   2) The compressor will automatically stop due to a certain safety protection action during the operation of the compressor, and the cause of the malfunction must be found out before it can be turned on. It is never allowed to switch on again by changing their settings or shielding faults.

   3) When the main engine shuts down due to a sudden power failure, the compressor may reverse because the bypass solenoid valve B cannot be opened. At this time, the suction stop valve should be closed quickly to reduce the reverse.

   4) If the machine is shut down for a long time in the low temperature season, all the water in the system should be drained to avoid freezing damage to the equipment.

   5) If you start the machine in a low temperature season, first turn on the oil pump, and press the motor to rotate the steering wheel to move the coupling to make the oil circulate in the compressor for sufficient lubrication. This process must be carried out in manual startup mode; if it is Freon refrigerant, start the machine Before turning on the oil heater to heat the lubricating oil, the oil temperature must be above 25℃.

    6) If the unit is shut down for a long time, the oil pump should be turned on every 10 days or so to ensure that there is lubricating oil in all parts of the compressor. Each time the oil pump is turned on for 10 minutes; the compressor is turned on once every 2 to 3 months, every 1 hour. Ensure that moving parts do not stick together.

   7) Before starting each time, it is best to rotate the compressor a few times to check whether the compressor is blocked or not, and to distribute the lubricating oil evenly in all parts.

2021.11.22-1


Post time: Nov-22-2021