Which of the air compressor and the cold dryer starts first?

According to many technical documents and industry specifications, the start-up sequence of air compressor station equipment should follow the following principles:

standard startup sequence:

1. start the cold dryer first., Wait for about 5 minutes to reach a stable working state;
2. restart the air compressor after the pressure reaches the set value (if necessary), start the suction dryer.

Principle and necessity:

• the cold dryer reduces the temperature of the compressed air to the dew point (2-10 ℃) through the refrigeration cycle, so that the water vapor is condensed into liquid water and discharged. Early start-up ensures that the drying system establishes a stable low temperature environment.
• If the air compressor is turned on first, the undried hot and humid air may directly enter the pipeline, resulting in condensed water corroding the equipment or affecting the gas quality.

Operation details:

1. inspection before start-up of cold dryer:

• confirm the refrigerant pressure (low pressure ≥ 0.4MPa, high pressure ≤ 1.5MPa);
• check the heat dissipation conditions of the condenser (the air-cooled type needs to clean up the dust, and the water-cooled type needs to control the water temperature ≤ 32 ℃).

2. Observation after starting the air compressor:

• whether the oil level is at 1/2 to 2/3 of the sight glass;
• whether the exhaust temperature is abnormal (usually ≤ ambient temperature +10 ℃).

Exceptions:

• first start-up after long-term shutdown: It is necessary to carry out a pre-cooling cycle for the cold dryer, or adopt the "inching start method" (press the emergency stop after the air compressor starts for 3-5 seconds, repeat 2-3 times) to establish the lubricating oil pressure.
• Extreme environment: If the ambient temperature is> 38 ℃, the cold dryer shall cooperate with the cooling tower or extend the pre-cooling time.

Shutdown Sequence Specification:

• turn off the air compressor first after the system is depressurized (about 10-15 seconds), turn off the cold dryer to prevent the undried air from recoil.

Summary:
following the start-up sequence of "cold dryer & rarr; air compressor" can ensure that the drying efficiency of compressed air is increased by about 30%, prolong the service life of pneumatic equipment, and avoid production accidents caused by condensed water. It is recommended to incorporate this process into the equipment operation procedures and regularly check the drainage system of the cold dryer (it is recommended to drain every 2 hours).