Analysis of the causes of Pressure Detection System failures and Troubleshooting methods
1.1 Oil filter pressure detection system
The detection position of the oil filter pressure detection system is on both sides of the oil filter, namely the high-pressure side (BP4) and the low-pressure side (BP3). The gas pressure is converted into an electrical signal by the pressure sensor and input into the central processing unit (CPU). When the pressure difference, that is, (△p2=BP4-BP3), reaches 0.7 kg/cm2, The alarm light on the control panel will flash and sound an alarm. When the pressure difference reaches 1.4 kg/cm ², the alarm light on the control panel will not only flash but also the internal bypass valve of the oil filter will open, allowing the lubricating oil to enter directly without passing through the oil filter
In the main engine head, it will not cause the unit to shut down, but it will bring the dirt in the lubricating oil into the engine head, affecting its service life.
During its operation for over a decade, this system has never experienced any malfunctions as long as it is maintained strictly in accordance with the user guide provided by the manufacturer. For the first running-in operation of a new machine, the first time to replace the oil filter element is 50 hours, and the next time is 1000 hours. During subsequent operations, as long as the oil filter element alarm light on the control panel flashes or the replacement time is reached, the oil filter element can be replaced in time to keep the oil filter system working normally.
1.2 Fault Analysis and Elimination of System Pipeline Pressure Detection System The system pipeline pressure detection system includes dry side exhaust pressure (BP2) and head exhaust pressure (BP1), as well as loading and unloading pressure detection circuits.
The exhaust pressure we usually refer to is the dry side exhaust pressure, that is, the gas pressure after the lubricating oil in the mixed gas is separated through the oil-gas separator. In fact, the exhaust pressure of the compressor head is the pressure of the mixed gas of air and lubricating oil.
(1) Fault Analysis and Troubleshooting Methods of Exhaust Pressure Detection System: The exhaust pressure detection system mainly uses a pressure probe to convert pressure signals into electrical analog signals and transmit them to the CPU. The CPU controls the operation or stop of the air compressor, and at the same time, various parameters such as pressure value and pressure difference are displayed on the screen.
When the air compressor has abnormal exhaust, the first step should be to check the pressure detection system. Under the condition of ensuring that the control pipeline system is normal, the replacement method should be adopted for testing, that is, to try a new pressure probe to determine if the pressure probe is damaged.
The pressure gauge is used to measure the pressure before the oil-gas separator in the oil and gas cylinder. Due to the resistance of the oil-gas separator, the minimum pressure valve and the pipeline, there is a pressure drop. The pressure indicated by the pressure gauge is higher than the exhaust pressure shown on the instrument panel (it may be lower during unloading). It is necessary to frequently observe and compare this pressure difference. When this pressure difference exceeds 0.1Mpa, the filter element of the oil-gas separator should be replaced in a timely manner.
The temperature sensor measures the exhaust temperature at the exhaust port of the machine head and displays it on the instrument panel. It uses PT100 platinum resistance as the sensitive component, featuring good linearity and high precision. In situations such as oil loss, insufficient oil volume, and poor cooling, it is possible to cause the exhaust temperature of the main engine to be too high. When the measured exhaust temperature reaches the alarm shutdown temperature value set by the microcomputer controller, the air compressor will automatically shut down. Depending on the model, the alarm and shutdown temperature has been set at 105℃, 110℃ or 115℃ before leaving the factory. Please do not adjust it at will.