Oil Differential Pressure Controller Principle And Common Alarm Causes

Oil Differential Pressure Controller Principle And Common Alarm Causes

The oil pressure differential controller functions by accurately measuring the difference between the lubricating oil pressure and the suction pressure of the refrigeration compressor. When this difference falls below a preset value, the oil pressure differential controller automatically cuts off the power supply, stopping the refrigeration compressor and preventing component damage due to insufficient lubrication.

In practical applications, oil pressure differential controllers typically employ thermal delay mechanisms. After each controller action, the internal thermal elements need to completely cool down before the refrigeration compressor can be restarted. This prevents damage to the equipment caused by frequent malfunctions and ensures the stability and reliability of the system.

Common Causes of Oil Pressure Differential Alarms

During the operation of the refrigeration compressor, oil pressure differential alarms can be caused by several factors:

1. Insufficient Lubricating Oil: Insufficient lubricating oil in the system leads to a low oil level, preventing the oil pump from drawing oil properly. Similar to a car engine running out of oil, this insufficient lubrication of various components triggers an oil pressure differential alarm.

2. Dirty Lubricating Oil: Over time, the oil in the system accumulates various impurities and becomes very dirty. This contaminated oil can clog the oil pump filter, hindering the normal flow of lubricating oil and thus affecting the stability of the oil pressure differential.

3. Relay Failure: As a core control component, the oil pressure differential relay, if malfunctioning, cannot accurately detect changes in oil pressure differential, failing to issue alarm signals or take timely shutdown protection measures, thus posing a potential risk to the equipment.

4. Oil Pump Failure: The oil pump is the power source for lubricating oil circulation. If the oil pump itself malfunctions, such as due to wear or damage, it will be unable to properly draw oil, preventing lubricating oil from being delivered to various parts that require lubrication, causing abnormal oil pressure differentials.

5. Refrigerant Contamination: A large amount of refrigerant mixed into the refrigeration oil will change the physical properties of the oil, causing the oil pressure to fail to build up normally. Just like a large amount of gas mixed into water, the water's pressure and flowability will be affected.

6. Compressor Refrigerant Return: When the compressor returns liquid refrigerant, excessive liquid refrigerant in the crankcase occupies space, affecting the normal circulation of lubricating oil and pressure build-up. At this point, the expansion valve needs to be adjusted, and the oil heating device should be checked for proper functioning.

7. Low Crankcase Oil Temperature: Low oil temperature increases the viscosity of the lubricating oil, reduces its fluidity, and hinders its circulation and pressure transmission within the system, thus triggering an oil pressure differential alarm.