Patent ID: 7121237

Claim:
A method for generating pressure pulses, by which a piston ( 4 ) is displaced in a first direction in a cylinder ( 3 ) as a pressurised fluid is permitted to temporarily flow into the cylinder ( 3 ) on one side of the piston ( 4 ), where after the piston ( 4 ) is displaced in a second direction while the fluid introduced therein is permitted to flow temporarily out of the cylinder ( 3 ), whereby a shaft ( 18 ) connected with the piston ( 4 ), during the displacement of the piston in one of its displacement directions, is displaced through, towards or away from the liquid in a chamber ( 17 ) that is filled with liquid and into which or out of which liquid can flow, the shaft ( 18 ) being in contact with the liquid during the displacement thereof, characterized in that the liquid-filled chamber ( 17 ) is blocked for the discharge of liquid when the piston ( 4 )/shaft ( 18 ) has reached a predetermined position.