Semi enclosed piston compressors: challenges and responses in daily use

Semi enclosed piston compressors: challenges and responses in daily use

Semi enclosed piston compressors occupy a core position in daily use and are widely used in various fields such as refrigeration, air conditioning, and chemical engineering. Its compact structure, easy maintenance, high reliability, and excellent energy efficiency make it favored by a large number of users.

However, this type of compressor also faces some challenges in use. Overheated exhaust temperature, pressure fluctuations, and lubricating oil emulsification may have a negative impact on the performance and lifespan of the compressor. This article will introduce the main reasons for the overheating of the exhaust temperature of refrigeration compressors from the following aspects and explore effective solutions.

1、 Return air temperature management

The temperature of the return air directly affects the performance of the compressor. When the insulation of the return air pipeline is poor, the overheating may far exceed 20 ° C. For every 1 ° C increase in return air temperature, the exhaust temperature will correspondingly increase by 1-1.3 ° C. To prevent refrigerant overheating in high-temperature environments, it is crucial to ensure good insulation of the return air pipeline.

2、 Motor thermal effect

For return air cooled compressors, the motor generates heat during operation, which in turn affects the suction temperature. The heat generation of a motor is influenced by power and efficiency, while the power consumption of a motor is closely related to factors such as displacement, volumetric efficiency, operating conditions, and frictional resistance. When selecting or improving compressors, these factors should be fully considered to reduce the impact of motor heating on exhaust temperature.

3、 Optimize compression ratio

The compression ratio directly affects the exhaust temperature. Excessive compression ratio can cause an increase in exhaust temperature. By increasing the suction pressure and reducing the exhaust pressure, the compression ratio can be effectively reduced, thereby controlling the exhaust temperature within a reasonable range. Optimizing the design of the evaporator is also an effective way to reduce compression ratio.

4、 Maintenance of condenser

The condenser is a crucial part of the refrigeration system, responsible for cooling the high-temperature refrigerant gas into a liquid state. During long-term use, dirt may accumulate in the internal pipelines of the condenser, affecting the heat dissipation effect; External environments such as high temperatures or stains may also hinder the normal heat dissipation of the condenser. Therefore, it is crucial to regularly inspect and clean the internal pipelines of the condenser to ensure its normal operation and heat dissipation effect.

5、 Monitoring of intake volume

Excessive or insufficient intake can affect the normal operation of the compressor. Excessive air entering the system will dilute the refrigerant, affecting its normal circulation and causing an increase in exhaust temperature. Therefore, it is necessary to regularly observe the intake volume, promptly detect and deal with air leaks or air pollution issues.

6、 Optimization of anti expansion process

After the start of the suction stroke, the high-pressure gas in the cylinder clearance will undergo a counter expansion process, which may lead to power loss and a decrease in suction volume. To solve this problem, the clearance should be reduced to reduce power loss during the anti expansion process; Simultaneously optimize the design of the cylinder and valve plate to reduce the contact area between gas and high-temperature surfaces.

7、 Evaporation temperature and refrigerant selection

The thermophysical properties of different refrigerants are different, so the amount of increase in exhaust temperature after undergoing the same compression process is also different. Unreasonable evaporator design, insufficient refrigerant, or excessively high external environmental temperature can all lead to excessively high evaporation temperature. For high-temperature application scenarios, refrigerants with high heat capacity should be selected.

Conclusion and suggestion: Compressor overheating may be a serious problem caused by improper design or maintenance of the refrigeration system. For problems caused by refrigeration systems, efforts should be made to improve the design and maintenance of the refrigeration system. Simply replacing a brand new compressor may not fundamentally solve the problem of overheating. Therefore, for each compressor that experiences overheating issues, in-depth analysis and inspection should be conducted to ensure the normal operation of the system and improve energy efficiency.