Application of air dryer on coach bus

Large coach bus vehicles and commercial vehicles generally use compressed air to brake, and the suspension devices of high-end passenger cars basically use airbags, so a large amount of compressed air is required. However, the compressed air contains moisture. When the moisture enters the vehicle pipeline, it will cause corrosion of metal components in the pipeline, aging and cracking of rubber seals, decomposition and failure of lubricating grease, and even cause pipeline blockage and other faults, seriously affecting our driving safety. Therefore, it is necessary to use a water removal device-car air dryer in the air brake system. Automobile air dryers use the physical adsorption effect of molecular sieves to remove moisture, oil, dust and other impurities from the compressed gas of the air compressor. Generally, they adopt an integral structure integrated with the unloading pressure regulating valve (air pressure regulating valve), and use it skillfully The action process of unloading and exhausting the pressure regulating valve makes the dry air in the regenerative air storage tank pass through the desiccant cylinder in reverse, and takes away the moisture adsorbed on the surface of the desiccant, and discharges it into the atmosphere, thereby realizing the reactivation of the desiccant, which can be used for a long time. Effectively absorb the moisture in the compressed air, keep the brake system of the car in good working condition, and ensure reliable braking and driving safety.
There are two types of air dryers on buses: adsorption type and molecular sieve type. The characteristic of the adsorption dryer is to directly absorb moisture into the desiccant until the desiccant is saturated and loses its adsorption capacity, and the desiccant cannot be reused. Molecular sieve type is a hydrated crystalline aluminosilicate with regular and uniform pores in its crystal structure. The pore diameter is on the order of molecular size, and the pore diameter can be used to sieve molecules of different sizes. Molecular sieve dryer is characterized by absorbing moisture in its pore size to achieve the purpose of drying the passing air. The bus is designed with back blowing, the purpose of which is to reversely blow the molecular sieve desiccant when the sewage valve is opened, so as to blow the moisture adsorbed in the pores of the molecular sieve desiccant out of the channel designed by the dryer and flow to the sewage outlet, that is, to achieve The purpose of desiccant reuse.
Automobile air dryer installation requirements and use requirements
1. Install vertically, with the exhaust port facing down, and the inclination shall not be greater than 5°.
2. The copper (molybdenum) pipe connected with the air compressor shall not be less than 5m to ensure that the humidity of the air entering the dryer is not greater than 65°C.
3. There should be a space of 30mm on the upper part of the dryer to replace the desiccant, and the regeneration tank should be installed near the dryer
4. Installing an air dryer can cancel the antifreeze pump, pre-drainage air storage tank and water discharge valve.
5. The use time of the dryer is 12~18 months at most (depending on the amount of oil and water brought by the air compressor pipeline). When water is found in the farthest air storage tank of the high desiccator, it means that the desiccant has failed and should be replaced.
6. Vehicles equipped with air dryers should try to use air compressors with less oil leakage, good valves and oil retaining rings, because oil pollution will reduce the adsorption of the desiccant. The effectiveness of the dryer depends largely on the length of the exhaust process. The system should keep the inflation process not to exceed 60% of each cycle, if it exceeds 60%, it will cause the recoil time
If the time is too short, water will be absorbed on the desiccant particles, which will reduce the drying effect of the desiccant and cause the condensation of moisture in the air storage tank.