Understanding the design function and working principle of each valve will give some help to the common fault solution of the air compressor!

No matter what brand (imported/domestic) oil injection air compressor, its compression working principle is the same, and the function of each valve is also roughly the same. If we can thoroughly understand each valve's design function and working principle, we will give some support and help to the common fault solution of the air compressor! 

The five valves of the Oil injection air compressor are the 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 gas consumption changes, the intake valve adjusts the opening degree of the valve body to match the gas consumption through the control system. It is the valve part that controls the gas production and no gas production of the air compressor.

Common corresponding faults:

1. The air compressor is not loaded. This fault control panel shows (no alarm; Run state 'load'; Injection pressure is very small or '0'; Nose outlet temperature < 70C°) can determine that the unit is not loaded. The problem lies in the unloading valve body, control loop, loading and unloading solenoid valve, and other parts, which need to be checked and rectified one by one.

2. The air compressor is not unloaded. This fault control panel shows (no alarm; Run state 'Unload'; Injection pressure increased > 4; Head outlet temperature > 80℃) can determine that the unit is not unloaded. The problem lies in the unloading valve body, control loop, loading and unloading solenoid valve, and other parts, which need to be checked and rectified one by one.

Min pressure valve

Function:

1. The opening pressure of the minimum pressure valve is about 4bar. Ensure that the pressure in the cylinder is not lower than this minimum pressure when the air is output, to avoid the reduction of the separation effect of the oil and gas separator caused by too fast air velocity.

2. When the machine starts, a certain pressure is established in the cylinder to ensure the lubricating oil circulation and provide the initial control pressure for the control loop.

3, with the function of a one-way valve, prevent the pipe network compressed air reflux to the machine inside.

Common corresponding faults:

1. Oil cylinder safety valve air injection during operation. This fault is because the minimum pressure valve is not opened, resulting in high pressure in the cylinder, the relief valve pressure protection.

2, running computer motor overload protection. This fault is that the minimum pressure valve is not opened, resulting in high pressure in the cylinder, the load of the main motor is aggravated, the current is increased, and the thermal relay protection stops.

3. The air compressor fails to start. This fault is that the minimum pressure valve is not closed strictly, resulting in the pipe network compressed air reflux, so that a certain pressure is generated in the cylinder, resulting in the unit can not start. When the air compressor starts, the control computer detects that there is a certain pressure in the oil cylinder, and the unit will not start.

4. The oil pressure of the air compressor is high when it is unloaded. This fault is that the minimum pressure valve is not closed strictly, and the compressed air in the pipe network returns when the unit is unloaded, which causes the pressure in the cylinder to rise, leading to an increase in oil pressure and the energy consumption of the unit.

 Oil Stop valve

Function:

After the air compressor is started, the oil cut-off valve is opened, and the lubricating oil passed through the oil filter is injected into the main engine. After the machine is shut down, the oil cut-off valve is closed, and the oil supply is cut off.

Common corresponding faults:

1. Jump off the machine at a high temperature quickly after starting. This fault is the oil break valve is not opened, and lubricating oil can not be sprayed into the nose, need to check and maintain the oil break valve.

2. High-temperature alarm of air compressor. This fault is that the oil cut-off valve is not fully opened and the amount of lubricating oil sprayed into the engine head is not enough. It is necessary to clean and maintain the oil cut-off valve.

3. When the machine stops suddenly, the lubricating oil is sprayed back into the air filter. This fault is caused by the delay or lax closure of the oil valve when the unit is suddenly shut down. It is necessary to clean and maintain the oil valve.

Check Valve

Function:

The compressed oil and gas mixture of the main engine is delivered to the cylinder in one direction to prevent the oil and gas mixture in the cylinder from spraying back into the nose and causing the rotor to reverse when the engine stops suddenly.

Common corresponding faults:

During the shutdown, the oil and gas mixture is sprayed back into the air filter. This fault is caused by the check valve being stuck or damaged when the unit is suddenly shut down. It is necessary to clean and maintain the check valve.

Thermostatic valve

Function:

1, temperature control spool through the principle of thermal expansion and cold contraction, extending and contracting to regulate the oil channel changes formed between the valve body and the shell, control the proportion of lubricating oil into the oil cooler, and ensure that the rotor temperature is within the control range.

2. The temperature control valve is the original to control the outlet temperature of the head not less than 68℃. When the oil temperature is low, the temperature control valve is closed, and the lubricating oil is sprayed directly into the head without the cooler for rapid heating so that the outlet temperature of the head rises rapidly and the condensed water in the compressed air is prevented from being generated in the oil cylinder.

Note:

1. The opening temperature of the thermostatic valve is generally marked at the spool.

2. The maximum opening temperature of the thermostatic valve is +15℃.