Baxter International Inc.

Linvatec Corporation

Robert C Kusmierczyk

Edward R Lindsay

James D Aid

Brian David Dross

Fred B Dinger, Iii

A simple and inexpensive method and apparatus are provided for increasing the pressure at which fluid may be delivered by a lavage/irrigation system.

Method and apparatus for increasing the pressure in a medical pumping

An improved chemical treatment system for hemodialysis machines, which includes a first three way valve which has a normally open position in the dialysis and rinsing modes of the hemodialysis machine. The valve in the normally open position couples a source of water through the valve to the bicarbonate pump for rinsing purposes before and after dialysis and the chemical treatment modes of the hemodialysis machine. In the chemical treatment mode of the hemodialysis machine the valve is switched to couple a source of treatment chemical through the valve to the bicarbonate pump. The chemical treatment system includes a second valve, which if in the normally open position, then only the bicarbonate portion and associated downstream portions will be chemically treated. In the closed position, the chemical will be switched to also flow through the whole hemodialysis machine from the water inlet to provide for a half or total system chemical treatment cycle. A vent valve coupled to the first valve can be included to further ensure that chemicals are not inadvertently entered into the hemodialysis machine.

Automated hemodialysis chemical treatment system with control valve and

A valveless positive displacement pump including a closed end cylinder having two fluid inlet and outlet ports adjacent the closed end. A piston reciprocably and rotatably driven in the cylinder and including a reduced area portion on one free end which communicates cyclically with the inlet and outlet ports to pump fluid through the positive displacement pump. The piston reduced area is a reduced radius portion to minimize air bubble buildup and to minimize fluid volume at the end of the piston stroke. The piston also has a gland area formed in the piston which cyclically communicates with a pair of ports to clean the piston and cylinder and prevent the buildup of solids. The piston and cylinder can be formed from a hard ceramic material for accuracy and wear resistance. The cylinder is closed by a resilient end cap to relieve pressures caused by piston movement when the inlet and outlet ports are closed. The piston is driven by a compliant ball support including a ball and socket biased between the piston and drive shaft to self adjust and compensate for misalignment of the pump. The angle between the drive shaft and the piston is variable to vary the fluid volume and aligned so that the end clearance between the piston and cylinder does not change as the angle is changed.

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Pinellas Park, FL, United States of America

Robert C Kusmierczyk