Project CategoryMain project classification
The refrigeration system test shall meet the following requirements :
(1) Compression refrigeration system shall be blown out of the system. The pressure shall be 0.6 MPa. The medium shall be dry air. The Freon system may be inspected with an inert gas and a cloth. No pollution is acceptable for 5 minutes. After blowing the dirt, the valve core of the valve in the system should be removed for cleaning (except for the safety valve).
(2) The airtightness test of the system shall be maintained at the test pressure according to the following table for 24 hours. The pressure drop during the first 6 hours shall not be greater than 0.03 MPa, and after 18 hours, except for the error caused by changes in ambient temperature, the pressure shall be qualified if there is no change in pressure.
Pressure of system air tightness test (absolute pressure MPa)
System pressure Piston refrigerator Centrifugal refrigerator
R717, R502 R22 R12, R134a R11, R123
Low voltage system 1.8 1.8 1.2 0.3
High voltage system 2.0 2.5 1.6 0.3
(3) For the remaining pressure of the vacuum test, the ammonia system should not be higher than 8KPa, and the Freon system should not be higher than 5.3KPa, which should be maintained for 24h. The ammonia system pressure is qualified without change. The Freon system pressure rise should not be greater than 0.53KPa. The centrifugal refrigerator is implemented according to the equipment technical documents.
(4) Filling the refrigerant in a piston refrigerator shall be performed in the following steps:
First charge an appropriate amount of refrigerant. The ammonia system is pressurized to 0.1∽0.2 MPa, and the phenolphthalein test paper is used for leak detection. The fluorine system is pressurized to 0.2∽0.3 MPa, and the halogen lamp or halogen leak detector is used for leak detection. When there is no leakage, press the technical file. Provisions for continued dosing. When filling, prevent inhalation of air and impurities, and it is strictly forbidden to heat the cylinder with warm water higher than 40 ℃ or other methods.
(5) The lithium bromide absorption refrigeration unit shall comply with the provisions of Article 3.4.5 of this code.
3.4.8 The system commissioning should meet the following requirements:
(1) The cooling water pump and refrigerant water pump should be started first during the trial operation.
(2) The oil temperature, oil pressure and water temperature of the piston refrigerator shall be implemented in accordance with the relevant items of Article 3.4.2 of this code. Exhaust temperature: R717, R22 must not exceed 150 ° C, and R12, R134a must not exceed 130 ° C.
(3) During the trial operation of the centrifugal refrigerator, the electric heating of the fuel tank should be started first, the oil temperature should be heated to 50∽55 ° C, and the cooling water and refrigerant should be supplied as required. Restart the oil pump, adjust the lubrication system, start the air recovery device according to the technical requirements of the equipment, remove the air in the system, start the compressor to gradually open the guide vanes, and quickly pass through the surge area. The oil temperature at the outlet of the oil cooler is 35∽55 ° C. The oil pressure difference between the oil filter and the fuel tank R11 unit should be greater than 0.1MPa, and the R12 unit should be greater than 0.2MPa.
(4) Before starting the screw compressor, the lubricating oil should be heated. The oil temperature should not be lower than 25 ° C, the oil pressure should be higher than the exhaust pressure by 0.15∽0.3MPa, the pressure difference between the front and rear of the oil filter should not be greater than 0.1MPa, and the cooling water inlet. The temperature should not be higher than 32 ℃, the suction pressure of the unit should not be lower than 0.05 MPa (gauge pressure), and the exhaust pressure should not be higher than 1.6 MPa. The relationship between exhaust temperature and oil temperature after cooling is shown in the table below.
Compressor exhaust temperature and cooled oil temperature (° C)
Refrigerant exhaust temperature oil temperature
R12 ≤90 30∽55
R22, R717 ≤105 30∽65
(5) The normal operation of the system with refrigerant should not be less than 8h.
(6) After the trial operation is normal, the refrigerator and oil pump must be stopped first (centrifugal and screw type refrigerators need to continue to supply oil for 2 minutes after the main engine is stopped before stopping the oil pump), and then stop the chilled water pump and cooling water pump. After the test run, the oil filter, strainer and desiccant should be disassembled and cleaned, and the lubricant should be replaced if necessary. After disassembling and inspecting, adjust the relevant devices to the ready-to-start state.
(7) The trial operation of the lithium bromide absorption refrigeration unit system shall be performed after the unit is cleaned, pressure tested, and the water, electricity, steam (or fuel) system is normal.
Start the cold water pump, the cooling pump, and then restart the generating pump and the absorber pump to circulate the solution of the unit. After the warm-up period passes, do the unit operation and record (temperature, water, steam consumption, etc.) at each point.