Leak detection, drainage, and vacuum operation methods of the refrigeration system in the computer room
The refrigeration system is indispensable for the computer room. Leak detection, sewage discharge, and vacuuming in the refrigeration system protect the refrigeration system so as to prevent the dirt in the system from entering the compressor and throttle valve, causing dirty blockage, cylinder fuzzing, The valve plate is not tightly sealed, which affects the normal operation of the compressor. Below, I will show you the operation methods of leak detection, drainage and vacuuming of the refrigeration system in the computer room.
The purpose of sewage discharge in the refrigeration system of the computer room is to remove the contaminants in the refrigeration system. Although every equipment and pipeline has been derusted and blown before installation, during the installation of the entire system, many pipes were still welded. Some welding slag, iron filings and dust will fall into the pipe from the welding port, and the dirt can be further removed through the sewage of the whole system. The vacuum operation of the refrigeration system should be carried out after the system cleaning, drainage and pressure test. Vacuum can not only further check the airtightness of the system, but also remove the air, moisture and other non-condensable gases in the system, so that the system can be filled with refrigerant.
Vacuum pumps should be used for vacuum pumping. For small refrigeration systems that use medium, small open-type and semi-hermetic compressors, without a vacuum pump, the compressor of the system itself can also be used for pumping. The product manual provided by the equipment manufacturer Except for prohibiting the use of this machine to pump air.
Leak detection and sewage operation methods:
First connect the pressure reducing valve to the nitrogen cylinder, connect the pressure reducing valve of the nitrogen cylinder to the ammonia adding valve of the system with a nitrogen pipe, open all the valves in the system except the valve communicating with the atmosphere, open the ammonia adding valve and the nitrogen valve , Fill the system with nitrogen to a low pressure and some experimental pressure, close the ammonia valve and nitrogen valve, and use a brush dipped in soapy water or detergent to modify all the joints and sealing parts of welds, pipe joints, flanges, valves, etc., and check leak.
(1) Remember to find the leaks and mark them. After finding a batch of leaks, the operator is located in the sewage operation station to unscrew the screw plug under the low-pressure circulating liquid reservoir (or gas-liquid separator) in all directions, and drain the Release nitrogen.
(2) Then make up the leak, screw on the screw plug of the low-pressure circulation reservoir (or gas-liquid separator), and fill with nitrogen from the beginning. The operator is located in the sewage operation station and unscrew the screw plug at the lower part of the central cooler in all directions, drain and release the nitrogen , Repeat the last two steps until there are no missing points.
(3) Close the inlet valve and drain valve of the low-pressure circulating reservoir (or gas-liquid separator), close the drain valve and drain valve of the drain barrel, the suction valve and drain valve of the compressor, and fill the system with nitrogen Some experimental pressures to high pressures.
(4) Some leak detections for high pressure, find the leaks, mark them, and after finding a batch of leaks, the operator is located in the sewage operation station to unscrew the screw plug in the lower part of the drain bucket in all directions to drain and release the nitrogen.
(5)Make up the leak, screw on the screw plug of the drain barrel, and fill with nitrogen from the beginning. The operator is located in the sewage operation station to unscrew the screw plug at the lower part of the high-pressure reservoir in all directions, drain the sewage and release the nitrogen, repeat the previous two steps until there is no Leak point.
Matters needing attention in the process of leak detection and sewage discharge:
(1) The blowdown is usually no less than 3 times, until the exhaust gas is free of water vapor, oil, rust and other debris.
(2) In practice, a wooden plug can also be used to block the sewage outlet. When the system has a certain pressure, the wooden plug is pulled out to expel the air quickly. This method is very good. But there are certain risks, and you must be careful and pay attention to safety during operation.
(3) The equipment pipes of the refrigeration system must be drained before operation to remove the welding slag, iron filings, sand and other dirt remaining in the system during the installation process. Prevent dirt from damaging the components of the refrigerator and the valves in the system, and prevent the system pipes from being blocked.
(4) When the ammonia refrigeration system discharges sewage, an air compressor or an ammonia refrigerator can be used to supply compressed air, and the pressure of the compressed air usually does not exceed 0.6 MPa. The sewage outlet should be set at the low of the pipeline, and the sewage work can be grouped and carried out in layers.
(5) In order to effectively use the explosive power and high-speed airflow of the compressed gas, a valve can be installed on the sewage outlet. When the pressure in the system increases, the valve can be quickly opened to allow the gas to be quickly discharged and bring out the dirt.
(6) In the process of sewage discharge, if significant leakage is found in the pipeline flange valve, it should be corrected in time. After the system is drained, the valve cores and filters of all valves in the system should be disassembled and cleaned.
(6)The blowdown of the Freon system is also carried out after the system is installed, and the 0.6MPa nitrogen is used to blow the sewage in stages. Sichuan Keyikang Electromechanical introduced the same methods and inspections as the ammonia system. When the freon system is discharged and pressure tested, compressed air cannot be used. The compressed air contains water vapor. If it remains in the freon system, it will cause the freon system to freeze or block The ice jam scene.
Vacuum operation method:
The operation method of vacuuming with a vacuum pump is to first close the valves that the system communicates with the outside (such as the filling valve, the air release valve, etc.), open all the connected valves in the system, unscrew the bypass hole plug of the exhaust valve, and open the bypass Connect the vacuum pump to the opening and start the vacuum pump for air extraction. The air in the system is difficult to exhaust. In order to achieve a certain degree of vacuum, the vacuum must be performed several times with an interval of about 10 minutes to balance the pressure in the system , The residual pressure of the ammonia system should be less than 7.999kPa (60mmHg), and the residual pressure of the Freon system should be less than 1.333kPa (10mmHg). After the vacuum reaches the standard, first close the bypass channel, then stop the vacuum pump, and remove the suction pipe. Screw on the screw plug of the bypass hole of the exhaust valve and keep it for 24 hours after vacuuming. The pressure rise in the system does not exceed 666.61Pa (5mmHg) as qualified. If the pressure rises quickly, the cause should be found and eliminated in time.
The compressor vacuum operation method is to close the suction valve and the exhaust valve, unscrew the bypass hole screw plug of the exhaust valve, install the exhaust pipe, open the bypass hole in order to discharge air, and close the system to the atmosphere. Valves (such as charging valve, air release valve, etc.), open all other valves in the system. If the condenser of the system is a water-cooled condenser, the cooling water in the condenser should be drained, otherwise it will be caused by the low temperature of the cooling water. To make the water in the system not easy to evaporate, difficult to be exhausted, force the contact of the oil pressure controller and the low pressure controller to be normally open, start the compressor, and slowly open the suction valve after the oil pressure is normal, and place the energy regulating device The smallest one. Due to the small diameter of the discharge valve of the refrigeration compressor, the suction valve cannot be opened very much at the beginning, and the energy adjustment device cannot be placed in high gear. As the pressure in the system decreases, the suction valve can be gradually opened and combined Load gradually and increase the amount of inhalation. In the process of pumping, the minimum oil pressure of the refrigeration compressor should not be lower than 50kPa. The vacuum should use intermittent evacuation. When the compressor continues to pump until no airflow sound is heard, the exhaust pipe is immersed in the refrigerator oil cup. Observe the bubbling of the nozzle.
If no bubbles emerge within 5 minutes, it can be considered that the gas in the system has been basically exhausted. If there are bubbles coming out of the exhaust pipe port for a long time, it means that the compressor itself or the system is leaking and should be checked and eliminated.
When checking, first close the compressor's suction valve and check whether the compressor itself is leaking. If the compressor is not leaking, no bubbles will appear in the oil container. It also shows that there is a problem in the system. Bubbles will continue to be produced, which is often caused by the shaft seal not being tightly sealed. If the bubbles are large at the beginning and then gradually become smaller, the time interval between the appearance of the bubbles will become longer and longer, which means that the shaft seal never closes to gradually close.
If the pipe end (when the insertion surface is not deep) is repeatedly sucked in and out of the refrigerating machine oil, it will not be seen when the pipe end is inserted deep into the oil. This situation is generally caused by the valve disc not being tightly closed. As a result, after heavy load use, there will be a certain improvement. After the spoon is vacuumed, the emptying channel should be closed first, and then the machine should be shut down to prevent air backflow due to the non-tight valve plate after shutting down.
Precautions for vacuuming
(1) After vacuuming, the compressor should be disassembled and washed, and replaced with new lubricating oil.
(2) When the vacuum is pumped to 8.659kPa, the oil pressure of the compressor is already very low and it can no longer be pumped.
(3) In the process of vacuuming with the compressor itself, if the compressor is equipped with a lubricating oil pump, as the vacuum in the system increases, the working conditions of the lubricating oil pump will deteriorate and cause damage to the moving parts of the machine. When the oil pressure (referring to the pressure difference) is less than 26.7kPa, the machine should be shut down immediately.
