[Mobile Equipment Technology Edition] Daily Question 20180207 Common faults in refrigeration systems (9.2)
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This post was last edited by YORK Industrial Refrigeration on 2018-2-10 10:36. From now on, in order to strengthen exchanges among sea friends, we have launched a [Daily Question] activity in the Animal Equipment Technology Edition. We hope that everyone will actively participate and make progress and improve together! ! ! award: Actively participate in 3 points of wealth, answer intact 10-15 wealth. This question is valid for two days. There will be no pre-scoring for more than two days. Last time we talked about over-compression and under-compression of screw compressors. What impact do over-compression and under-compression have on the compressor? Both under-compression and over-compression first cause an increase in the power consumption of the refrigeration unit. Under-compression causes an increase in the gas transmission coefficient. High-load operation causes accelerated aging of the compressor bearings, which intensifies the vibration and noise of the compressor. ============================== Premium promotion: Moving equipment---York screw compressor maintenance process https://bbs.hcbbs.com/thread-1806833-1-1.html Moving equipment---York Quantum control center upgrade https://bbs.hcbbs.com/thread-1804837-1-1.html Moving equipment---GEA Grasso screw compressor overhaul https://bbs.hcbbs.com/thread-1800467-1-1.html Moving equipment---Howden screw compressor disassembly and maintenance in the UK https://bbs.hcbbs.com/thread-1832529-1-1.html Moving equipment---Japanese Maekawa MYCOM screw compressor disassembly and maintenance https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=
The internal pressure ratio is the degree to which the screw compressor rotor itself increases the pressure, while the external pressure ratio is jointly determined by the condenser and evaporator. When the external pressure ratio is greater than the internal pressure ratio, we call it undercompression. When the external pressure ratio is less than the internal pressure ratio, we call it overcompression. Both situations lead to a decrease in unit efficiency (non-compressor efficiency).
The internal pressure ratio is the degree to which the screw compressor rotor itself increases the pressure, while the external pressure ratio is jointly determined by the condenser and evaporator. When the external pressure ratio is greater than the internal pressure ratio, we call it undercompression. When the external pressure ratio is less than the internal pressure ratio, we call it overcompression. Both situations lead to a decrease in unit efficiency. (Copied by a master, not yet fully digested)
Both over-compression and under-compression will increase the power consumption of the compressor without increasing the mass flow rate, thereby reducing the refrigeration coefficient.
Undercompression generally refers to a screw compressor. When the compressor ends compression, the exhaust pressure is less than the condensation pressure, which will form an instant backflow. The gas will not be discharged until the exhaust pressure of the rotor is balanced with the condensation pressure. This backflow will increase the power consumption of the compressor without increasing the mass flow rate, thereby reducing the refrigeration coefficient.
Both over-compression and under-compression will increase the power consumption of the compressor and reduce the efficiency of the unit.
Over or under compression occurs, which increases the power consumption of the compressor. One of the important features of the screw compressor's working process is the internal compression process. The best working condition of the compressor is that the internal pressure ratio is equal to the external pressure ratio. If the two are not equal, whether it is under-compression or over-compression, the economy will be reduced.
.Over-compression and under-compression increase the extra power consumption of the compressor, reduce the compressor performance, and the exhaust temperature will be correspondingly higher.
Undervoltage: The voltage does not reach the normal voltage. Overvoltage: The voltage is much higher than the normal voltage!
Over or under compression occurs, which increases the power consumption of the compressor. One of the important features of the screw compressor's working process is the internal compression process. The best working condition of the compressor is that the internal pressure ratio is equal to the external pressure ratio. If the two are not equal, whether it is under-compression or over-compression, the economy will be reduced.
When the compression end pressure in the compressor is not equal to the pressure of the gas in the exhaust pipe, that is, when the internal pressure ratio is not equal to the external pressure ratio, additional work loss will occur, thereby reducing the indicated efficiency of the compressor. Therefore, the actual operating conditions of the compressor should be equal to or close to the design conditions so that the compressor can achieve high operating efficiency.