Pulseless pump

Claim 1

A multiple cylinder pump, comprising a. a plurality of hollow cylinders each having geometrically opposed first and second boundaries, b. a plurality of plungers, each having a first end and a second end, said first end of each plunger being adapted to enter one of the cylinders through an aperture in said first boundary, c. reciprocating means causing the first end of the plunger to reciprocate within the cylinder, d. sealing means provided at each aperture, to control leakage through the aperture, the sealing means including a sealing case concentric to each plunger and open to the first end of the plunger and sealing material within each said case and contacting said plunger, e. adjusting means positioned on said second boundary adapted to adjust the sealing ability of the sealing means, the adjusting means including spaced ribs extending longitudinally within each cylinder, the ribs extending from the second boundary into the sealing case, and operable to compress the sealing material to increase its sealing ability without interrupting pumping operation, f. an access port on each second boundary adapted to allow removal of said sealing means, the movement of a first end of the ribs in the case being limited to movement within the case by a radially directed element connecting the case to the ribs and allowing the case to be removed from the pump through the port by pulling on a cap connected to said ribs, and g. input and output parts suitable for controlling flow through the cylinders.