Abstract: A dispenser for dispensing controlled quantities of liquid from a bottle includes a piston, which is movable in a cylinder and serves to suck and discharge an adjustable quantity of liquid. The cylinder is secured to a valve block, which contains a suction valve and a discharge valve. A cylindrical sleeve surrounds the cylinder and defines an annular clearance therewith. To change the length of the stroke of the piston and the quantity of liquid which is to be sucked and discharged depends on the stroke length, an adjustable stop and a fixed stop, which is engageable with the adjustable stop and are accommodated in the clearance.

Abstract: The present invention is concerned with a hand pipette with a piston arrangement which is forced upwardly by an elastic force, the piston of which is displaceable in a removable pipette tip and the piston rod of which can be displaced downwardly against the elastic force by external operation to such an extent that the piston, at the lower end of the piston stroke, is at the lower end of the pipette tip, the lower end of the pipette being provided with a holding ring through which the piston rod passes and which carries the removable pipette tip at the bottom of the holding ring and at the top is mounted so as to be axially displaceable and lockable.

Abstract: Disclosed is a pipette device which accommodates a detachable filling device and a detachable piston. The stroke length of the piston is determined by the selective engagement of an abutment, movable with the piston, with stepped surfaces cut into a sleeve movable within an enclosing housing. A control member accessible at the housing exterior is angularly shifted to move the sleeve and thus select the step with which the abutment will engage, thereby determining the length of the working stroke of the piston.