[Mechanical Equipment Technology Edition] Daily Question 20171226: Common Faults in Refrigeration Systems (4.2)
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This post was last edited by YORK Industrial Refrigeration on 2018-1-2 at 08:14. Starting from now, in order to enhance communication among users, a 【Daily Question】 campaign has been launched on the Mechanical Equipment Technology forum; we hope everyone will participate actively to progress and improve together! ! ! Rewards: 3 wealth points for active participation, 10-15 wealth points for correct answers. This question is valid for two days; no score will be assigned after that period. In a refrigeration compressor, what is the reason why the compressor automatically switches between loading and unloading states once the energy regulation device has reached its set position? Answer: Faulty four-way valve, faulty oil piston. Check the electrical components and the valve part of the four-way valve; inspect the sealing rings of the oil piston. https://attach01.hcbbs.com/forum/201712/27/083237nbgb4v9n7dbhbd9b.gif =============================== Premium promotions: Mechanical equipment——Summary of work by equipment managers for 2017 https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1881872 Mechanical equipment——Maintenance procedures for York screw compressors https://bbs.hcbbs.com/thread-1806833-1-1.html Mechanical equipment——Upgrading of York Quontum control centers https://bbs.hcbbs.com/thread-1804837-1-1.html Mechanical equipment——Major repairs of GEA Grauso screw compressors https://bbs.hcbbs.com/thread-1800467-1-1.html Mechanical equipment——Disassembly and maintenance of British HOWDEN screw compressors https://bbs.hcbbs.com/thread-1832529-1-1.html Mechanical equipment——Disassembly and maintenance of Japanese Maekawa MYCOM screw compressors https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=
When cooling with a fixed heat source, the temperature is high at the beginning, so full load operation is required; once the temperature drops, reduced load operation is necessary.
1. Insufficient oil pressure. 2. Clogged oil pipe. 3. Oil contamination inside the cylinder has caused it to stick. 4. The distribution valve is not assembled properly, or the tie rod or rotating ring mechanism is incorrect.
1. The inlet valve of the solenoid directional control valve is not sealing properly, allowing oil to continue flowing in. 2. The return valve of the solenoid directional control valve is not sealing properly, resulting in pressure loss.
The thermal load at work is changing. When the cooling capacity of the compressor is greater than the heat load, the working cylinder should be unloaded; otherwise, it should be loaded. When the heat load is comparable to the cooling capacity in summer, some cylinders need to be removed in winter. When cooling with a fixed heat source, the temperature is high at the beginning, so full load operation is required; once the temperature drops, partial load operation is necessary. That’s why compressors are equipped with energy regulation devices
After the load of the unit’s energy regulation system is set, automatic loading and unloading should occur; the possible causes are: 1. Control system failure, 2. Blockage or sticking in the oil system, 3. Leakage in the electromagnetic directional valve, 4. Blockage in the high-pressure system