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

Abstract: 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.

Abstract: 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.

Abstract: An automated disinfection system for a hemodialysis machine having a proportioning pump includes a manifold block having a check valve for connection to a container of disinfection solution. The manifold block has an outlet connected to the suction line of the pump and an inlet connected to a warm water source via a solenoid valve. A timing and control circuit controls the solenoid valve to produce a water rinse cycle when the solenoid valve is open and a disinfection cycle when the solenoid valve is closed. The check valve closes when positive pressure is present in the manifold block during a rinse cycle and opens to admit solution to the pump when negative pressure is present in the manifold block during a disinfection cycle.