Introduction
Screw compressors, as core compression equipment widely used in industrial production, their operating conditions directly affect production efficiency and equipment safety. Among the numerous operating parameters, exhaust temperature is one of the most crucial control indicators. Whether it is an oil-injected screw air compressor or a refrigeration screw compressor, the exhaust temperature is strictly limited. This article will delve into why the exhaust temperature of screw compressors is so strictly limited, conducting a comprehensive analysis from multiple dimensions such as hazard mechanisms, standard ranges, influencing factors, and control measures.
Five core hazards of excessively high exhaust temperature
1. High-temperature carbonization and failure of lubricating oil
Screw compressors rely on lubricating oil to achieve the triple functions of lubrication, cooling and sealing. When the exhaust temperature is too high, the lubricating oil will face a serious threat
Viscosity decrease: High temperatures reduce the viscosity of the lubricating oil, making it impossible to form an effective oil film, which leads to accelerated wear of the friction pairs
Oxidation and coking: Long-term high-temperature operation can cause the lubricating oil to oxidize and decompose, forming black gel-like carbon deposits that deposit inside the screw main unit, oil circuit system and radiator
Acidic substance formation: Lubricating oil undergoes a chemical reaction with air at high temperatures, generating acidic substances that corrode metal parts and sealing materials
Industry experience shows that when the exhaust temperature exceeds 110℃, the risk of lubricating oil coking increases significantly. When the temperature exceeds 120℃, the problem of carbon deposits will deteriorate rapidly
2. Risk of thermal expansion and jamming of mechanical components
The precisely fitted rotors, bearings and other components inside the screw compressor are extremely sensitive to temperature.
Rotor thermal expansion: High temperatures cause excessive expansion of the rotor, which may get stuck inside the die head, leading to serious mechanical failures
Decline in sealing performance: High temperatures accelerate the aging of sealing components, increase the risk of gas leakage, and reduce compression efficiency
Accelerated bearing wear: Poor lubrication leads to abnormal wear of bearings, and in severe cases, it can cause bearing bush burning accidents
3. Damage to the motor and electrical system
For screw compressors with built-in motors or electrical control systems:
Aging of insulating materials: For every 10℃ increase in the temperature of electrical insulating materials, their lifespan will be halved
Motor overheating and burnout: High-temperature environments directly threaten the insulation of motor windings, which may lead to motor burnout
Control system failure: Temperature sensors, PLCS and other control components may operate abnormally at high temperatures
4. Decline in system efficiency and performance
Excessively high exhaust temperature will directly affect the overall performance of the compressor.
Reduced gas transmission coefficient: High temperatures cause changes in gas density, reducing the actual gas transmission volume
Increase in shaft power: To maintain the same output, more energy is consumed, raising operating costs
Increased cooling load: High-temperature gases increase the burden on the subsequent cooling system, affecting the overall system efficiency
5. Safety hazards and shortened equipment lifespan
Risk of cylinder block rupture: Extreme high temperatures may cause the cylinder block or head of the compressor to rupture, leading to safety accidents
The lifespan of the equipment is significantly shortened: Long-term high-temperature operation will significantly reduce the service life of the compressor and increase the cost of replacement
Production interruption risk: High-temperature malfunctions may cause equipment to shut down, affecting the normal production process
Ii. Standard Range of Exhaust Temperature for Screw Compressors
According to the international standard ISO1217:2016 and industry general norms, the exhaust temperature standards for different models of screw compressors are as follows:
The recommended exhaust temperature range for compressor types: The maximum allowable temperature for oil-injected screw air compressors is 80℃ - 95℃≤110℃. Oil-free screw air compressor: 85℃ - 100℃, ≤105℃ Refrigeration screw compressor: 70℃ - 120℃≤130℃ Centrifugal air compressor: 70℃ - 90℃≤100℃
Note: Specific values should be referred to the equipment manual or consulted with the manufacturer. Special working conditions (such as in the pharmaceutical and food industries) may require stricter temperature control
Normal judgment criteria
The exhaust temperature of most screw air compressors should be between 70℃ and 120℃
The exhaust temperature should not exceed +30℃ above the ambient temperature
The temperature should remain relatively stable and should not experience significant fluctuations
Iii. Common Causes of excessively High Exhaust Temperature
Cooling system failure (accounting for approximately 40%)
Cooler blockage: Dust and oil stains adhere to the surface of the cooler, reducing the heat dissipation efficiency
Abnormal cooling fan: Blade breakage, motor damage or loose belt resulting in insufficient air volume
Cooling water issues (water-cooled models) : Insufficient flow, excessively high water temperature or valve failure affecting circulation
2. Lubricating oil issues (accounting for approximately 25%
Insufficient or leaked oil: This leads to poor lubrication and increased frictional heat generation
Oil quality deterioration: After long-term use, the lubricating oil oxidizes and deteriorates, losing its lubricating and cooling properties
Poor oil return: The flow rate of the lubricating oil decreases, and the amount of oil entering the die head reduces
3. Malfunction of the temperature control valve (accounting for approximately 15%
Stuck temperature control valve: Hinders the normal circulation of lubricating oil and affects the heat dissipation of the equipment
Valve failure: Lubricating oil is directly sprayed into the machine head without passing through the condenser, causing the exhaust temperature to rise
4. Overload operation of equipment (accounting for approximately 10%
Insufficient air intake: The air filter is clogged or the pipeline leaks, forcing the air compressor to operate at high load
Excessively high exhaust pressure: Pipe blockage or valve failure increases the compression ratio, generating excessive heat
Excessive continuous operation time: Heat cannot be dissipated in time, resulting in an increase in temperature
5. Environmental and maintenance factors (accounting for approximately 10%
High ambient temperature or poor ventilation: The external ambient temperature is too high or the space where the equipment is located has poor ventilation
Equipment aging: After long-term use, components wear out and heat dissipation performance declines
Improper maintenance: Failure to clean the cooler, replace the filter element or check the oil circuit on time
Iv. Exhaust Temperature Control Measures
Daily monitoring and management
Regular inspection: Monitor parameters such as exhaust temperature, head temperature, and intake temperature
Trend observation: Pay attention to the temperature change trend and promptly detect abnormal fluctuations
Early warning system construction: Install real-time sensors (such as PT100 temperature probes) and set alarm thresholds
2. Maintenance and care measures
Regularly change the lubricating oil: Replace it according to the recommended cycle by the manufacturer to ensure the quality of the oil
Clean the cooler: Regularly remove dust and oil stains from the surface of the cooler
Check the oil circuit system: Ensure the oil level is normal and the oil circuit is unobstructed without leakage
Clean carbon deposits: Regularly clean the carbon deposits in the oil circuit and radiator using a dedicated cleaning agent
3. Fault handling process
When abnormal exhaust temperature is detected, the following steps should be followed for handling:
1. Stop the machine immediately for inspection: to prevent further damage to the equipment or accidents
2. Identify the cause: Based on the equipment manual and the manufacturer's suggestions, investigate possible causes
3. Problem-solving: Take corresponding measures based on the identified causes, such as replacing components or adjusting parameters
4. Verify the effect: After restarting, continuously monitor the temperature changes to confirm that the problem has been solved
V. Summary
The core reason why screw compressors have strict restrictions on exhaust temperature lies in the fact that high temperatures can cause multiple risks such as carbonization and failure of lubricating oil, thermal expansion and jamming of mechanical components, damage to motors and electrical systems, decline in system efficiency, and safety hazards.
Key points: Normal range: 70℃ - 120℃ (depending on the model). Danger threshold: ≥110℃ requires vigilance, and the risk significantly increases when ≥120℃. Core hazards: lubricating oil failure, mechanical wear, motor burnout, and efficiency decline. Control focus: Cooling system, lubricating oil management, and maintenance of temperature control valves. Maintenance suggestions: Regular monitoring, timely maintenance, and establishment of an early warning system
Conclusion: Strictly controlling the exhaust temperature of screw compressors is a key measure to ensure the safe operation of equipment, extend its service life, and reduce maintenance costs. Enterprises should establish a complete temperature monitoring system, strengthen daily maintenance and upkeep, and ensure that the exhaust temperature is always within a reasonable range, thereby achieving efficient and stable operation of the equipment.
References: The content of this article comprehensively refers to industry technical standards and suggestions from equipment manufacturers. For specific parameters, please refer to the equipment manual.