Refrigeration & Equipment Engineering

5. GAS CHARGING SYSTEM

GAS CHARGING SYSTEM

Aim: To charge Ammonia gas to the refrigeration system.

Apparatus: Ammonia gas service cylinder, open ended spanner set, main fold gauge set, charging line,hand lever, wrench, weighing scale, water pipe, bucket, cotton waste, etc.

Working principle: Refrigerants are obtainable in cylinders. The amount of refrigerant transferred to the refrigeration system is determined by placing the service cylinder on a weighing scale before and after the charging or by placing the service cylinder on a weighing scale during the charging operation. The charging of refrigerant to the system is carried out when the compressor is under running condition. When the entire refrigerant is charged to the system all connections should be plugged or capped to keep air or water out of the system. As a precaution measure the safety goggles, wet cloth, water should beused during the refrigerant charging to the system.

Procedure:

• Weigh the NH₃ (Ammonia) refrigerant cylinder before charging.
• Connect NH₃ (Ammonia) cylinder to the charging line with the help of flexible pipe (High Pressure pipe).
• Start the compressor and take down all the liquid from the system to the receiver.
• Make sure the relieve valve is in closed condition.
• Open the charging valve No.11 and the valve on the ammonia cylinder (crack open).
• Keep the compressor in running condition.
• Monitor the liquid compound pressure gauge provided next to valve No.11 (10kg/cm²).
• When the liquid compound pressure gauge comes to 0 kg/cm² Close the valve No.11 and also close the valve of the ammonia cylinder.
• Remove the flexible pipe line connection from the ammonia cylinder.
• Weigh the cylinder after charging ammonia to the refrigeration system.