Fuel couplings
Fuel couplings – general information
Fuel couplings include :
- API dry disconnect couplings
- API vapour recovery couplings
- Gravity drop couplings
Commonly used for loading and unloading fuel from road tankers. They are usually permanently attached to bottom loading arms at loading/unloading terminals (fuel depots). A bottom loading method is widely used in the petrochemical industry, as it is far superior to top loading in terms of economy, safety and speed. A bottom loading station is cheaper to build than a top loading station. In bottom loading, the operator works on the ground, which increases his safety. The bottom method reduces the danger of generating static electricity and forming vapours during loading/unloading. The bottom loading is much faster (the entire operation takes place at the ground level) and several chambers can be filled simultaneously. These advantages make the bottom loading method increasingly popular.
Principle of operation
API couplings are divided into couplings for a liquid phase (fuel) and a gaseous phase (vapour). The API couplings for the liquid phase are made in one, 4” API size. A coupler (hose part) and an adapter (tank part) are equipped with poppet valves, which are opened by rotating the lever of the coupler. However, the valves open only after connecting the coupler with the adapter. It is also possible to open the valve of the adapter on the tanker, without connecting with the coupler. API vapour couplings are generally of CAMLOCK 4” type, fitted with a valve in the adapter (tank unit), which opens with a probe (pilot) – a pin inside the CAMLOCK coupler (hose unit). The API range of fuel couplings also includes gravity couplings (free flow unloading).
Standards
API couplings are designed and manufactured in accordance with API RP-1004 standard (American Petroleum Institute). An equivalent standard is EN 13083 for the adapter of the coupling for bottom loading and unloading, and EN 13081 for the adapter and coupler for vapour recovery. These couplings are compatible with the couplings made by different manufacturers in compliance with the standards above.
Application
API couplings are used for fuel road tanker bottom loading and unloading. They are usually permanently attached to bottom loading arms at loading/unloading terminals (fuel depots). A bottom loading method is widely used in the petrochemical industry, as it is far superior to top loading in terms of economy, safety and speed. A bottom loading station is cheaper to build than a top loading station. In bottom loading, the operator works on the ground, which increases his safety. The bottom method reduces the danger of generating static electricity and forming vapours during loading/unloading. The bottom loading is much faster (the entire operation takes place at the ground level) and several chambers can be filled simultaneously. These advantages make the bottom loading method increasingly popular.
Gravity drop fuel couplings
Gravity drop fuel couplings (API coupling adapters) allow for unloading using gravity, by connecting API tank unit with a standard CAMLOCK coupling. API couplings are made of aluminium. Working pressure of API fuel couplings is usually about 6 bar.