The functions and troubleshooting of each component of the screw air compressor

         The function of the components of the oil-injected screw air compressor is introduced, and the working principle of the components is analyzed.  Precautions in maintenance and analysis and elimination of individual faults.

1. Lubricant

1.1 Lubricating oil has lubricating, cooling and sealing functions.

 1.1.1   Pay attention to the oil level of the lubricating oil.  Lack of oil will cause high temperature and carbon deposition of the unit, and it will also cause accelerated wear of the moving parts and damage the service life of the unit.

 1.1.2   To prevent condensed water in the lubricating oil, the operating oil temperature is preferably around 90°C, and resolutely prevent the oil temperature during operation from being lower than 65°C.

1.2  Lubricating oil composition: base oil + additives.

         Additives have the following functions: anti-foam, anti-oxidation, anti-corrosion, anti-solidification, wear resistance, descaling (rust), more stable viscosity (especially at high temperature), etc.

        The lubricating oil can be used for at most one year, and the lubricating oil will deteriorate if the time is too long.

2. Screw air compressor components function

2.1  Air filter function

        The most important task is to prevent impurities such as dust in the air from entering the air compressor system.  Filtration accuracy: 98% of 0.001mm particles are filtered out, 99.5% of 0.002mm particles are filtered out, and 99.9% of particles above 0.003mm are filtered out.

2.2  Oil filter function

         All wear-causing impurities and dirt are removed from the oil without separating the special additives added.

   Filter paper precision: 0.008mm size particles filter out 50%, 0.010mm size particles filter out 99%.  The counterfeit filter paper has not been tested by heating lubricating oil, has fewer folds, greatly reduces the filter area, and the spacing of the folds is uneven.  

         If the air in the air inlet is dusty, after the lubricating oil has been used for a period of time, the filter paper will be severely clogged, and the filter will hinder the flow of lubricating oil.  If the pressure difference of lubricating oil entering the oil filter is too large (cold start or filter blockage), the oil circuit will lack oil, and the lubricating oil temperature will rise, which will damage the rotor.

3. Oil and gas separator working principle

3.1  Function of oil and gas separator

        It is mainly to separate the compressor lubricating oil from the oil-air mixture, and continue to remove the lubricating oil particles in the compressed air.  Entering the oil and gas barrel (composed of oil and gas separator, minimum pressure valve, safety valve and container shell), the oil and gas mixture undergoes three kinds of separation: centrifugal separation, gravity separation (oil is heavier than gas) and fiber separation.

        Separation process: the oil-gas mixture enters the oil-gas barrel along the tangential direction of the outer wall of the oil-gas separator, 80% to 90% of the oil is separated from the oil-gas mixture (centrifugal separation), and the remaining (10% to 20%) oil sticks in the oil-gas separator  The surface of the outer wall of the device is separated (gravity separation), and a small amount of oil enters the interior of the oil-gas separator (fiber separation), and is pressed back into the screw host cavity through the oil return pipe.

3.2  The gasket of the oil and gas separator is conductive

   Since air and oil pass through the glass fiber, static electricity will be generated between the two separation layers. If the two metal layers are charged with static electricity, there will be a dangerous situation of electrostatic discharge accompanied by electric sparks, which may cause oil and gas  The separator exploded.

   Good oil and gas separator accessories ensure the electrical conduction between the separator core and the oil and gas barrel shell.  The metal components of the air compressor have good electrical conductivity, which can ensure that all static electricity can be exported in time to prevent the generation of electric sparks.

3.3  The adaptability of the oil-gas separator to the pressure difference

        The pressure difference that the design of the oil-air separator can bear is limited. If the filter element of the separator exceeds the maximum value, the oil-air separator may rupture, and the oil in the compressed air cannot be separated, which will affect the air compressor or cause separation.  The core is completely damaged, and the high pressure drop of the oil-gas separator may also cause the separator to catch fire.

        There may be the following 4 reasons for the excessive high pressure difference: the oil separator is blocked due to dirt, the reverse flow of air, the internal pressure fluctuates greatly, and the core of the oil-gas separator is counterfeit.

3.4  The metal of the oil and gas separator is normally electroplated and usually will not be corroded

         Depending on the ambient conditions (temperature and humidity) and the operating conditions of the compressor, condensation may form inside the air-oil separator.  If the oil-gas separator is not electroplated, a corrosion layer will be formed, which will have a damaging effect on the antioxidant of the compressor oil, and will significantly reduce its service life and the flash point of the oil.

3.5  Measures to ensure the service life of the oil-gas separator

        Accumulated dust, residual oil, air pollutants or wear can reduce the service life of the oil separator.

3.5.1 The air filter and oil filter can be replaced in time and the oil change time can be observed to limit the dust entering the compressor oil.

3.5.2 Use the correct anti-aging and water-resistant lubricating oil.

To be continued......