Don't underestimate this little can, if you don't replace it, the brakes may fail

The driving safety of the vehicle is closely related to the braking performance. The braking failure caused by the failure of the braking system is the main reason and also the main factor causing traffic accidents. 

1. Why install an air dryer?

In the air brake system of the vehicle, the air compressor outputs air containing impurities such as water vapor. If not treated, the water vapor may be converted into liquid water again, and combined with other impurities to cause corrosion, even under extreme temperatures. It will freeze the air pipe and cause the valve body to fail.

In the past, the treatment of compressed air mainly used the method of wet air storage cylinder, that is, a wet air storage simple pre-drainage device with a water release valve was installed in the air circuit. This kind of device has a certain drying and filtering effect, but it cannot completely remove the water in the air path, and it is necessary to regularly discharge the water, oil and other dirt accumulated in the air storage cylinder, which is very inconvenient to use.

2. the role of the air dryer

The automobile air dryer is used to remove impurities such as moisture and oil droplets in the compressed air. It is installed after the air compressor and before the four-circuit protection valve to cool, filter and dry the compressed air to remove the water vapor, Oil, dust and other impurities, provide dry and clean air for the braking system.

The automobile air dryer is a regenerative dryer with molecular sieve as its desiccant. Molecular sieve is a synthetic desiccant product with strong adsorption to water molecules. Its main component is an alkali metal aluminosilicate compound with a microporous structure, and there are many uniform and tidy pores and holes in the structure.

When water molecules or other molecules pass through the pores, they are adsorbed on the inner surface, which has the function of screening out the molecules. Molecular sieves have a large adsorption weight ratio and can still hold water molecules well in a high temperature environment of 230 °C.

1. Cooling, separation, drying

(1) Cooling: When the high-temperature compressed air output by the air compressor passes through the spiral pipeline between the steel body and the outer cylinder, it fully contacts the steel body, and the steel body absorbs heat and dissipates it;(2) Separation: The cooled compressed air rotates at a high speed in the spiral channel. Using the principle of centrifugal force, impurities such as oil, water droplets, and dust in the airflow can be separated from the channel wall.

(3) Drying: Molecular sieve desiccant adsorbs moisture in high-pressure airflow to obtain dry air.

2. Automatic voltage regulation

The inside of the dryer is constantly inflated and unloaded, and the one-way valve can effectively prevent the gas from flowing backwards, which can ensure that the air pressure is always maintained within a certain range, which provides a guarantee for the normal operation of the braking system.

3. Desiccant activation regeneration and automatic sewage discharge

Desiccant activation regeneration and automatic blowdown are realized in the process of unloading and exhausting.

When the dryer is unloaded, a backflush airflow is formed. When the backflushing air passes through the desiccant, the moisture adsorbed on the molecular sieve is taken away to realize the activation and regeneration of the desiccant, which greatly prolongs the service life of the desiccant, reduces the replacement frequency of the dryer, and improves the drying efficiency of the dryer.

At the same time, the backflushing airflow will discharge the separated impurities such as oil and powder in the cavity into the atmosphere through the exhaust port to realize the function of automatic sewage discharge. It can clean the filtered dirt in time, prevent the air circuit of the dryer from being blocked, reduce the frequency of failures, and avoid the trouble of manual decontamination, which has a positive effect on the working performance of the dryer and the entire braking system.

4. Safety pressure protection

When the air path inside the dryer is blocked, or the pressure regulating valve fails, its internal air pressure will continue to rise. If the air pressure rises to the safety protection pressure, the internal air pressure acts on the exhaust valve to overcome the spring force of the exhaust valve, so that the exhaust valve opens and exhausts to avoid danger.

5. Automatic heating and exhaust muffler

The automatic heating device is composed of electric heating rod, temperature control switch, electric plug, connecting wire and so on. The heating device can automatically heat the dryer according to the ambient temperature to prevent the pressure regulating valve and the exhaust valve from being frozen and avoid working failures.

A muffler is installed outside the exhaust port, which can greatly reduce the noise generated when unloading the exhaust.

3. The composition of the air dryer

The air dryer is mainly composed of shell, drying cylinder, pressure regulating valve, exhaust valve, one-way valve and heater.

There are three working air ports on the shell, one of which is the air inlet and the other two are the air outlet.

The drying cylinder is sealed and installed on the upper end of the shell, and there is a molecular sieve desiccant in it to complete the absorption of water and the filtration of impurities. The heating rod inside the heater can heat the dryer and prevent the internal moisture from freezing in extremely cold environments.

A one-way valve is installed in a gas outlet to prevent backflow of drying gas. The pressure regulating valve and the exhaust valve cooperate to complete the process of automatic pressure regulation, unloading and exhausting.

4. The use of air dryer precautions

The performance of the air dryer is directly related to the performance and service life of the braking system. The selection of the air dryer is very important to ensure the working stability and driving safety of the braking system.

The drying cylinder of the air dryer has a built-in desiccant, which has a certain service life and should be replaced in time according to the maintenance mileage given by the manufacturer, and it is advisable to replace it before winter.

Air dryer is small in size, multi-functional, easy to replace, simple to maintain, good effect of cooling, separation and drying, stable and reliable performance, low noise, long life, strong load capacity, and it is an auto part commonly used in air brake system internationally at present. But in the process of use, you must pay attention to replacing it on time to ensure its good effect.