Piston for measuring volume of e.g. petrol in tank of motor vehicle, has circular scanning joint whose periphery is surrounded by ring and made of deformable material, where elements of piston are threaded at end of connecting slide

摘要

The piston (7a) has a support disc (9) whose diameter is less than a diameter of a measurement chamber, and a circular monoblock scanning joint (13) whose periphery is surrounded by a ring (13c) with an external diameter larger than that of the chamber. A circular hole (13b) is pierced at a central part of the joint, and elements of the piston are threaded at an end of a connecting slide (8). The joint is made of deformable material such as polymer material i.e. PTFE, containing graphite. Sealing rings (10, 11) are mounted on the disc and have diameters equal to the diameter of the chamber.