Application Suitable for use with clean water that does not containa brasive particles and liquids that are not chemically aggressive towards the materials from which the pump is made. As a result of their compactness, reliability and the factth at they are easy to use, they are suitable for use in domestic applications such as the distribution of water in combination with small pressure sets, for the irrigation of gardens and allotments, for drawing water from tanks and for all those other situations where air or water maybe present in the water to be pumped. The pump come scomplete with a flap-check valve. The pump should be installed in an enclosed environ ment,or at least sheltered