Air Dryer for Sinotruk HOWO TX HOHAN NX SITRAK G7 C7H Truck Brake System Spare Parts

Core Function: "Drying and Purifying" the Brake Air Circuit

The air dryer is installed between the air compressor and the four-circuit protection valve. It is responsible for removing moisture, oil mist, and solid impurities from the compressed air, preventing internal corrosion of the brake system, pipe icing in winter, and valve sticking. For heavy-duty trucks, this is a key link in ensuring brake response sensitivity and driving safety.

Main Performance Features

Efficient Dehumidification and Anti-freeze
Desiccant (activated alumina or molecular sieve) is used to adsorb water vapor from the compressed air. Some models can reduce the pressure dew point to -40°C, ensuring that pipes and valves do not freeze in cold environments. Some supplier data claims a dehumidification efficiency of over 95%.

Automatic Regeneration
When the system reaches rated pressure and the air compressor unloads, the dryer uses a small amount of dried compressed air to back-flush the desiccant, carrying the adsorbed moisture out to the atmosphere, thereby enabling reuse of the desiccant and extending the replacement interval. This regeneration cycle is the key mechanism by which the dryer maintains long-term effectiveness.

Oil Mist and Impurity Filtration
In addition to moisture, oil mist from the air compressor can also contaminate brake valves. Some models are equipped with coalescing filter elements or cyclone separation structures that can remove 99% of oil mist aerosols, protecting downstream precision components such as relay valves and quick-release valves.

Integrated Pressure Regulation and Protection
Many modern air dryer assemblies integrate the pressure regulating valve and the four-circuit protection valve into one unit (i.e., the Air Processing Unit, APU), automatically regulating system pressure while drying the air, and isolating faults when any circuit fails to ensure normal air supply to the remaining circuits.

Key Technical Parameters (Multi-source Reference)

Because of the wide range of applicable models and numerous suppliers, the following parameters are typical values from various sources, not official data for any specific model:

Purchasing and Maintenance Notes

Significant model differences: The TX, NX, G7, C7H and other models you listed span a wide range, and different power configurations and chassis versions may use dryers/APUs with different port specifications (such as M39×1.5 threads) or integrated forms. Some models have adopted WABCO compact APUs to replace traditional standalone dryers.

Heating function: Models used in cold regions usually integrate an electric heater (12V/24V) that automatically activates at low temperatures to prevent the exhaust port from icing and blocking.

Replacement interval: The desiccant filter element is a consumable item, with a general recommendation of replacement at about 2 years or 300,000 km, but the interval should be shortened in high-humidity environments. If frequent water discharge from the air tank, slow brake valve response, or pipe icing in winter occurs, it usually indicates that the dryer has failed.

Recommendation: Use the actual vehicle VIN or the part number on the original dryer as the basis, and confirm the applicable model through Sinotruk original parts channels before purchasing, to avoid installation failure due to mismatched ports or integrated forms.