The Application of Coalescers in Aviation Fuels: A Key Technology for Safeguarding Flight Safety

 I. Introduction

In the aviation field, flight safety has always been of the utmost importance. An essential part of ensuring flight safety is to provide aircraft with clean and impurity-free fuel. During the entire process from the refinery to the aircraft's fuel tank, aviation kerosene will inevitably come into contact with moisture and solid impurities. If these harmful substances are not effectively removed, they may lead to engine failures and even cause serious accidents.

Today, we will conduct an in-depth exploration of a device that plays a crucial role in the purification of aviation fuels - the coalescer.

 II. Background of Aviation Fuel Purification

Aviation jet fuel (aviation kerosene) starts from the refinery and goes through multiple storage, transportation, and refueling processes before finally entering the aircraft's fuel tank. During this process, the fuel will absorb moisture and solid dust from the atmosphere. In addition, the manufacturing, installation, and commissioning of oil pipelines and tanks may also introduce a large amount of moisture and impurities. If these mechanical impurities and free water are not effectively removed, they may clog the fuel lines, resulting in insufficient engine power, or even cause the engine to stall and lead to serious flight accidents.

According to statistics, 33% of flight accidents are caused by engine failures, and among these engine failures, 50% are caused by particulate matter in jet fuel. Therefore, ensuring the cleanliness of aviation fuel is not only the key to extending the engine's lifespan but also an important measure to safeguard flight safety.

 III. Working Principle of the Coalescer

To effectively remove moisture and impurities from aviation fuel, a filter separator is usually installed in the aviation fuel supply system, and the coalescer is one of the core components of it. The filter separator can continuously process the fuel during the oil transportation process, integrating the functions of filtering impurities and dehydrating to ensure the cleanliness of the fuel.

Inside the filter separator, there are two sets of filter cartridges with different functions: coalescing filter cartridges and separation filter cartridges.

When the fuel flows through the filter separator, it will go through four key processes: filtration, coalescence, sedimentation, and separation.

1) Filtration: The fuel first passes through the primary coalescing filter cartridge to filter out solid impurities.

2) Coalescence: Tiny water droplets coalesce into larger water droplets in the coalescing layer.

3) Sedimentation: The large water droplets settle to the bottom of the filter due to gravity.

4) Separation: The fuel then passes through the secondary separation filter cartridge, and the unsettled water droplets are completely separated by the water-repellent effect of the separation filter cartridge and finally settle in the water collection tank and are discharged through the drain valve.

After this series of treatments, the impurities and moisture in the fuel are effectively removed, and finally, clean jet fuel is obtained for the use of the aircraft.

 IV. Maintenance and Replacement of the Coalescer

To ensure the normal operation of the coalescer, regular maintenance and replacement of filter cartridges are essential. The following are several common situations for replacing filter cartridges:

Replacement conditions for coalescing filter cartridges:

1) The service life exceeds one year;

2) The pressure difference exceeds 0.1 MPa (1 kg/cm²);

3) The filter cartridge is damaged (the pressure difference suddenly drops).

Replacement conditions for separation filter cartridges:

1) The filter cartridge is damaged;

2) The filter cartridge fails the water spray test.

By regularly checking and replacing the filter cartridges, it can be ensured that the coalescer is always in the best working state, thereby ensuring the cleanliness of aviation fuel.

 V. Conclusion

As a key device in the purification of aviation fuels, the coalescer ensures the cleanliness of aviation fuel through its efficient filtering and separation functions, providing an important guarantee for flight safety. Whether in every link from the refinery to the aircraft's fuel tank, the coalescer is silently safeguarding the safety of each flight.

Flight safety is no trifling matter, and the application of the coalescer is precisely the manifestation of the aviation industry's ultimate pursuit of safety.