Patent attributes
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.
