Rotary pump

A rotary pump having a housing defining an annular chamber with an inlet port and outlet port which are located on either side of a partition extending across the chamber;

• a flexible annular diaphragm forming one side of the chamber facing a wall on the housing forming the second side of the chamber, the diaphragm being sealed at its innermost and outermost edges to the housing;
• legs which are integral with the diaphragm, extending away from the diaphragm, and extending azimuthally around the diaphragm;
• a swashplate assembly comprising inner and outer clamp rings connected to the legs of the diaphragm such that in use, movement of the swashplate causes the diaphragm to press precessively against the wall of the housing to force fluid drawn in at the inlet port on one side of the partition around the chamber and to expel it at the outlet port at the other side of the partition;
• and
• a sealing ring between the swashplate assembly and the diaphragm.