Function and corresponding fault treatment of five valves of air compressor

No matter what brand of (imported / domestic) fuel injection air compressor, its compression working principle is the same, and the functions of each valve are roughly the same. If you can thoroughly understand the design function and working principle of each valve, you will give some support and help to solve the common faults of the air compressor!

The five valves of oil injection air compressor are：（Unloatding valve）、(Min pressure valve)、(Oil stop valve)、（Check valve）、（Thermostatic valve）, The following explains the functions and troubleshooting of each valve one by one

（Unloatding valve）

Function: when the air consumption changes, the air inlet 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 gas production and non gas production of the air compressor.

Common corresponding faults: 

1. The air compressor is not loaded. The fault control panel display (no alarm; operation status' loading '; injection pressure is very small or' 0 '; head outlet temperature < 70c °) can determine 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 display (no alarm; operation status' unloading '; fuel injection pressure rise > 4; head outlet temperature > 80 ℃) can determine 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.

Min pressure valve 

Function: 1. The opening pressure of the minimum pressure valve is about 4 bar 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 the reduction of the separation effect of the oil-gas separator due to the excessive air flow rate.

2. When the machine is started, a certain pressure is established in the oil cylinder to ensure the circulation of lubricating oil and provide initial control pressure to the control circuit.

3. It has the function of one-way valve to prevent the compressed air in the pipe network from returning to the inside of the machine.

Common corresponding faults: 1. During operation, the oil cylinder safety valve blows air. This fault is because the minimum pressure valve is not opened, resulting in high pressure in the oil cylinder and pressure relief protection of the safety valve.

2. Motor overload protection occurs when the computer is running. The fault is that the minimum pressure valve is not opened, resulting in too high pressure in the oil cylinder, increased load of the main motor, increased current and shutdown of thermal relay protection.

3. The air compressor failed to start. The fault is that the minimum pressure valve is not tightly closed, resulting in the backflow of compressed air in the pipe network, resulting in a certain pressure in the oil cylinder, resulting in the failure of the unit to start. When the air compressor is started, when the control computer detects a certain pressure in the oil cylinder, the unit will not start.

4. The oil pressure is too high when unloading the air compressor. The fault is that the minimum pressure valve is not closed tightly, and the compressed air in the pipe network returns when the unit is unloaded, which increases the pressure in the oil cylinder, resulting in the increase of oil pressure and the increase of unit energy consumption.

Oil stop valve 

Function: after the air compressor is started, the oil cut-off valve is opened to inject the lubricating oil through the oil filter into the main engine. After shutdown, the oil cut-off valve is closed to cut off the oil supply.

Common corresponding faults: 

1. Rapid high temperature tripping after startup. The fault is that the oil cut-off valve is not opened and the lubricating oil cannot be injected into the machine head. It is necessary to check and maintain the oil cut-off valve.

2. Air compressor high temperature alarm. The fault is that the oil cut-off valve is not fully opened and the amount of lubricating oil injected into the machine head is not enough. The oil cut-off valve needs to be cleaned and maintained.

3. In case of sudden shutdown, lubricating oil is sprayed back into the air filter. This fault is caused by the delayed or lax closing of the oil shutoff valve when the unit is suddenly shut down. The oil shutoff valve needs to be cleaned and maintained. Check valve 

Function: the compressed oil-gas mixture of the main engine is transported to the oil cylinder in one direction to prevent the oil-gas mixture in the cylinder from spraying back into the head during sudden fault shutdown, resulting in rotor reverse rotation.

Common corresponding faults: during shutdown, the oil-gas mixture is sprayed back into the air filter. This fault is caused by the jamming or damage of the check valve during the sudden shutdown of the unit. The check valve needs to be cleaned and maintained.

Thermostatic valve 

Functions: 

1. The temperature control valve core extends and contracts according to the principle of thermal expansion and cold contraction to adjust the change of the oil passage formed between the valve body and the shell, control the proportion of lubricating oil entering the oil cooler, and ensure that the rotor temperature is within the control range.

2. The temperature control valve is an original part that controls the outlet temperature of the machine head 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 machine head without passing through the cooler for rapid heating, so as to rapidly increase the outlet temperature of the machine head and prevent condensate in the compressed air from generating in the oil 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 ℃.

Accessories consultation Tel.: 021-64130070 / 13918092362 / 13661552078/13916285293