Industry news

No matter what kind of brand (imported / domestic) oil injection air compressor, its compression working principle is the same, and the function of each valve is roughly the same. If we can thoroughly understand the design function and working principle of each valve, we will give some support and help to solve the common faults of air compressor!
The five valves of the injection air compressor are: unloading valve, min pressure valve, oil stop valve, check valve and thermostatic valve. The functions and troubleshooting of each valve are explained one by one.
Unloading valve
Function: when the air consumption changes, the intake valve adjusts the opening degree of the valve body through the control system to match the air consumption. It is a valve to control the air compressor gas production and non gas production.
Common corresponding faults: 1. The air compressor is not loaded. The fault control panel displays (no alarm; operation status' loaded '; injection pressure is very small or' 0 '; head outlet temperature < 70c °) and it can be concluded that the unit is not loaded. The problem lies in the unloading valve body, control circuit, loading and unloading solenoid valve and other parts, which need to be checked and eliminated one by one.
2. The air compressor does not unload. The fault control panel displays (no alarm; operation status' unloading '; injection pressure rise > 4; head outlet temperature > 80 ℃) and it can be concluded that the unit does not unload. The problem lies in the unloading valve body, control circuit, loading and unloading solenoid valve and other parts, which need to be checked and eliminated one by one.
Minimum pressure valve
Function: 1. The opening pressure of the minimum pressure valve is about 4 bar, so as to ensure that the pressure in the oil cylinder is not lower than the minimum pressure when the air is output, so as to avoid that the separation effect of the oil-gas separator will be reduced due to the too fast air flow rate.
2. When the machine is started, a certain pressure is established in the cylinder to ensure the circulation of lubricating oil and provide the initial control pressure for the control circuit.
3. It has the function of one-way valve to prevent the return of compressed air from the pipe network to the inside of the machine.
Common corresponding faults: 1. Air injection of oil cylinder safety valve during operation. This fault is due to the fact that the minimum pressure valve is not opened, resulting in too high pressure in the cylinder and pressure relief protection of the safety valve.
2. When the computer is running, motor overload protection appears. The fault is that the minimum pressure valve is not opened, resulting in high pressure in the cylinder, heavy load of the main motor, increased current and shutdown of thermal relay protection.
3. Air compressor start failed. The fault is that the check valve of the minimum pressure valve is not closed tightly, resulting in the return of compressed air in the pipe network, generating a certain pressure in the oil cylinder, resulting in the unit unable to start. When the air compressor starts, the control computer detects that there is a certain pressure in the oil cylinder, the unit will not start.
4. The oil pressure of air compressor is too high when unloading. The fault is that the minimum pressure valve is not closed tightly, the compressed air in the pipe network flows back when the unit is unloaded, so that the pressure in the oil cylinder increases, resulting in the increase of oil pressure and the increase of energy consumption of the unit.
Oil cut-off valve
Function: the oil cut-off valve is opened after the air compressor is started, the lubricating oil passing through the oil filter is injected into the main engine, the oil cut-off valve is closed after shutdown, and the oil supply is cut off.
Common corresponding faults: 1. High temperature trip after startup. This fault is that the oil cut-off valve is not opened, and the lubricating oil cannot be injected into the head. It is necessary to check and maintain the oil cut-off valve.
2. Air compressor high temperature alarm. This fault is that the oil cut-off valve is not fully opened, and the amount of lubricating oil injected into the head is not enough, so it is necessary to clean and maintain the oil cut-off valve.
3. When the machine is stopped suddenly, the lubricating oil is injected back into the air filter. This fault is caused by the delay or lax closing of the oil cut-off valve when the unit is shut down suddenly, so it is necessary to clean and maintain the oil cut-off valve.
Check valve
Function: the compressed oil and gas mixture of the main engine is delivered to the oil cylinder in one way to prevent the oil and gas mixture in the cylinder from being injected back into the head when the engine stops suddenly due to failure, which causes the rotor to reverse.
Common corresponding faults: oil and gas mixture is injected back into air filter during shutdown. This fault is caused by the one-way valve stuck or damaged during the sudden shutdown of the unit. It is necessary to clean and maintain the one-way valve.
Temperature control valve
Functions: 1. The temperature control valve core adjusts the oil channel change between the valve body and the shell through the principle of hot expansion and cold contraction, extends and contracts, controls the proportion of lubricating oil entering the oil cooler, and ensures that the rotor temperature is within the control range.
2. The temperature control valve is the original part to control the head outlet temperature not less than 68 ℃. When the oil temperature is low, the temperature control valve is closed, and the lubricating oil is directly injected into the head without cooler for rapid heating, so as to make the head outlet temperature rise rapidly and prevent the condensate in the compressed air from generating in the cylinder.
Note: 1. The opening temperature of thermostatic valve is generally marked at the valve core. 2. The maximum opening temperature of thermostatic valve is the marked temperature + 15 ℃.