US 7,325,478 B2 · High pressure low volume pump

Abstract

A piston carrier supports an elongated, slender piston rod for reciprocation in a pump cylinder to pump fluid into and out of the cylinder. The piston rod is made of a material such as sapphire or zircon and has a diameter less than about ten millimeters, and the pump can provide flows of from about 50 nanoliters to about 250 microliters per minute at pressures of several hundred bars. A drive motor rotates a threaded screw and a drive nut of a drive system applies a linear drive force to the piston carrier. A ball and socket connection between the drive system and the piston carrier avoids the need for precise alignment to prevent breakage of the fragile piston. A magnet in the socket holds the ball in place and avoids the need for a spring or other mechanical holder. The socket also includes a ring of a low reluctance material surrounding the ball to increase the magnetic retention force.

Claims32

Dependent claims

A high pressure, low volume pump comprising:

(a) a piston;
(b) a piston holder, the piston holder having a first end and a second end disposed opposite the first end, wherein the piston is mounted to the first end of the piston holder and a ball is disposed on the second end of the piston holder;
and
(c) a socket provided at an end of a piston drive system, the socket comprising
(1) a base wall;
(2) a side wall extending axially from the base wall, the side wall surrounding at least a part of the ball;
and
(3) a magnet held in the base wall, the magnet holding the ball in the socket using magnetic force.

5 more elements

Dependencies are inferred from the claim text.

High pressure low volume pump

Life of this patent

High pressure low volume pump

Life of this patent

Abstract

Claims32