Winter is a crucial period for the operation of compressed air systems and also a season with a high incidence of faults in refrigerated air dryers. As an important part of the post – treatment equipment of the compressed air system, the refrigerated air dryer is responsible for removing moisture from the compressed air to prevent pipeline corrosion, equipment damage, and product quality problems. However, the low – temperature environment in winter poses many challenges to the normal operation of refrigerated air dryers. This article will analyze the common faults of refrigerated air dryers in winter from the following aspects:
I. Refrigeration System Faults
1. Refrigerant Leakage
Cause Analysis:
- In a low – temperature environment, the seals in the refrigerant pipeline are prone to failure due to thermal expansion and contraction, resulting in refrigerant leakage.
- Frequent start – stop operations and temperature fluctuations in winter can cause stress on the pipeline, leading to weld cracking or joint loosening.
- After long – term use, components such as evaporators and condensers may experience corrosion and perforation, resulting in refrigerant leakage.
Fault Manifestations:
- The dryer cannot reach the set dew point temperature, and the water content at the compressed air outlet exceeds the standard.
- The operating current of the compressor is lower than the normal value.
- The evaporator has abnormal frosting or no frosting.
Solutions:
- Regularly check the refrigerant pipeline for leaks, with a focus on easily leaking parts such as valves, joints, and welds.
- Replace aging or damaged seals and pipeline components in a timely manner.
- After a leak occurs, immediately stop the machine, repair the leak point, and then evacuate and refill the refrigerant.
2. Compressor Faults
Cause Analysis:
- In a low – temperature environment, the viscosity of the lubricating oil increases and its fluidity deteriorates, resulting in insufficient lubrication of the compressor.
- Frequent start – stops in winter subject the compressor to greater mechanical stress and accelerate wear.
- Refrigerant leakage causes the compressor to operate over – heated and damages internal components.
Fault Manifestations:
- The operating noise of the compressor increases and the vibration intensifies.
- The operating current of the compressor is abnormally high or low.
- The compressor over – heat protection device operates frequently, and the motor may even burn out.
Solutions:
- Select lubricating oil with good low – temperature performance and regularly check the oil level and oil quality.
- Avoid frequent start – stop operations and adopt variable – frequency control technology to adjust the compressor speed.
- Regularly maintain the compressor and replace worn – out components.
3. Severe Frosting of the Evaporator
Cause Analysis:
- In a low – temperature environment, the surface temperature of the evaporator is lower, making it more prone to frosting.
- Excessively high air humidity or large air flow leads to an excessive load on the evaporator.
- The defrosting system of the dryer malfunctions and cannot defrost in time.
Fault Manifestations:
- The air temperature at the dryer outlet is too low, and icing may even occur.
- The processing capacity of the dryer decreases and the energy consumption increases.
- In severe cases, the evaporator pipeline may be frozen and cracked.
Solutions:
- Regularly check and clean the dust and debris on the surface of the evaporator to maintain good heat transfer efficiency.
- Adjust the operating parameters of the dryer, such as reducing the air flow or increasing the evaporation temperature.
- Repair the defrosting system failure in a timely manner to ensure the normal operation of the defrosting device.
II. Control System Faults
1. Sensor Faults
Cause Analysis:
- In a low – temperature environment, the accuracy of the sensor decreases or even fails.
- The sensor is exposed to a humid environment for a long time and is easily damaged by moisture.
- Vibration and impact can also damage the sensor.
Fault Manifestations:
- The dryer cannot accurately detect and control parameters such as temperature, pressure, and dew point.
- The control system frequently gives false alarms or malfunctions.
- The operating parameters of the dryer are abnormal, resulting in a decline in processing effects.
Solutions:
- Select sensors that are resistant to low temperatures and humidity and calibrate them regularly.
- Do a good job in sealing and protecting the sensors to avoid moisture and vibration.
- Regularly check the working status of the sensors and replace the damaged sensors in a timely manner.
2. Solenoid Valve Faults
Cause Analysis:
- In a low – temperature environment, the insulation performance of the solenoid valve coil decreases, and it is prone to short – circuit or open – circuit.
- The solenoid valve spool is stuck or the seal is not tight, resulting in abnormal opening and closing.
- After long – term use, the internal spring of the solenoid valve ages, resulting in poor spool reset.
Fault Manifestations:
- The dryer defrosting system cannot start or stop normally.
- The compressed air bypass valve cannot be adjusted normally, resulting in pressure fluctuations.
- The dryer cannot start or stop normally.
Solutions:
- Regularly check the insulation performance of the solenoid valve coil and replace the damaged coil in a timely manner.
- Clean the solenoid valve spool and valve seat to ensure that the spool moves flexibly and the seal is good.
- Replace the aging spring and adjust the reset force of the spool.
III. Other Common Faults
1. Failure of the Pipeline Filter
Cause Analysis:
- In winter, the air is dry and there is a lot of dust, which is easy to block the filter.
- The filter has not been cleaned or replaced for a long time.
Fault Manifestations:
- The processing capacity of the dryer decreases and the energy consumption increases.
- The oil content at the compressed air outlet increases.
- In severe cases, the dryer cannot operate normally.
Solutions:
- Regularly clean or replace the air filter.
- Select a filter with a higher filtration accuracy and adjust the replacement cycle according to the actual situation.
2. Drainage System Faults
Cause Analysis:
- In a low – temperature environment, the drainage pipeline is easy to freeze and block.
- The drain valve is not tightly sealed or is damaged, resulting in water leakage.
- The condensate is not discharged in time, resulting in water accumulation.
Fault Manifestations:
- Water accumulates at the bottom of the dryer, affecting the normal operation of the equipment.
- The water content at the compressed air outlet increases.
- In severe cases, the drainage pipeline may be frozen and cracked.
Solutions:
- Regularly check and clean the drainage pipeline to prevent freezing and blocking.
- Repair the damaged drain valve in a timely manner and adjust the opening of the drain valve.
- If necessary, insulate the drainage pipeline.
The low – temperature environment in winter poses severe challenges to the normal operation of refrigerated air dryers. To ensure the stable operation of the dryer in winter, the following aspects need to be addressed:
- Do a good job in the daily maintenance of the equipment and regularly check and replace vulnerable parts.
- Reasonably adjust the operating parameters of the equipment and optimize them according to changes in the ambient temperature and load.
- Strengthen the inspection of the equipment and promptly detect and eliminate potential faults.
- Develop a complete emergency plan to ensure a rapid response when the equipment fails.
Only by doing the above can the failure rate of refrigerated air dryers in winter be effectively reduced, and the safe, stable, and efficient operation of the compressed air system be guaranteed.
