The British Standard is using on the delivery side the non-symmetrical quick connection coupling type Instantaneous, consisting of a male and female part, which is simply pushed together. Springloaded plungers in the female part grip in the gap of the male part. The couplings will be disconnected by pulling knobs and twist knobs. On the suction side round threaded suction hose couplings and equipment type BSRT are in use, while the female part always has to be swivelling. The correct use of the female and male parts has to be taken into consideration.