Pressure fluid-delivery device

A pressure fluid-delivery device comprising, a cylinder, a piston which is arranged to be moved backwards and forwards in the cylinder, and which has an end portion, which together with adjacent end portion of the cylinder defines a front cylinder space, where axial movement of the piston forwards relative to the cylinder causes a reduction in the volume of the front cylinder space and a delivery of pressure fluid from this space, a reservoir for the fluid, and a seal which is V-shaped in cross-section and which is mounted in an annulus between the cylinder and the piston to prevent fluid flow out of the front cylinder space via the annulus, and which has a bottom portion and two legs which are interconnected via the bottom portion and project away from each other and forwards from said bottom portion, a first leg springingly sealing an outlet opening of a channel which communicates with the reservoir in such a manner that the first leg seals the outlet opening when the pressure of the fluid in the front cylinder space is greater than the pressure of the fluid in the reservoir, but opens the outlet opening when the pressure of the fluid in the reservoir is greater than the pressure of the fluid in the front cylinder space, said seal resting on a forwardly facing, radially outwardly extending surface of the piston, the seal's first leg projecting slantingly radially inwards and being arranged to come into abutment against an axially forwardly extending portion of the piston, and the seal's second leg projecting slantingly radially outwards and being arranged to slide on and constantly abut against an inner surface of the cylinder surface, wherein the first leg has greater elasticity than the second leg.