Zeolite molecular sieve is an excellent desiccant for air brake system dehydration, which is widely used in transportation vehicles, to protect the air brakes of the cars, trucks, buses, ships and trains from failure with effective dehydration.
Why Air Brake Systems Need Dehydration?
Air brake system relies on ambient air, which contains water vapor and has a higher moisture concentration after compression. And the compressed water vapor is target that needs to be processed.
The compressed water vapor can enter various parts of the brake system through the pipeline, affecting the performance and service life of inside pipes and gas tanks. When the lubricating oil and dust blended in with the water, blockage may occur.
For example, the brake oil is hydrophilic. If the water exists in the brake system, the oil will vaporize at high temperatures, generating gas which can cause abnormal braking pressure, softening or failure of the pedal.
At low temperatures, the water will freeze in the brake system, creating ice that can block critical hoses and valves. This can cause valves to stick and brakes to fail, which are very dangerous and may lead to serious traffic accidents.
Working Process Of Air Brake Dehydration
In the air brake systems, zeolite molecular sieves are typically installed in the air dryers. When compressed air passes through the air dryer, water is absorbed by the molecular sieves, ensuring that the output air is dry.
During the adsorption phase, the compressed air passes through the zeolite molecular sieve layer, where the water molecules are firmly adsorbed within the microporous structure of the molecular sieve.
During the regeneration phase, the air brake system incorporates a regeneration cycle (using dry air backwash or heating), to release the adsorbed water from the molecular sieve, allowing the molecular sieve to be reused.
Molecular Sieves For Air Brake Dehydration
Type 4A zeolite molecular sieve is the most typically used desiccant in the air brake systems. It has a high water absorption capacity and economical cost-effectiveness, which is suitable for air drying with low dew point requirements, such as truck and bus air dryers.
Type 4A (or 3A) zeolite molecular sieve composite with activated alumina, also can be used in the air brake systems, especially for high-end dehydration requirements. For example, heavy-duty vehicles, railway brakes, and air dryers that require long service life and strong oil resistance capabilities.