Systems for monitoring fluid flow in an extracorporeal blood circuit are described. The blood circuit of such systems can include plod pump having a pumping chamber of the blood pump separated from a control chamber of the blood pump by a flexible diaphragm. The control chamber can be configured to transmit positive or negative pressure to operate the diaphragm. The system can include a pressure sensor configured to measure pressure in the control chamber of the blood pump, and a controller configured to receive information from the pressure sensor and to control the delivery of pressure to the control chamber of the blood pump. The controller can also be configured to cause the application of a time-varying pressure waveform on the blood pump diaphragm during a fill-stroke of the blood pump, and to monitor a pressure variation in the control chamber measured by the pressure sensor. When so configured, such controller can transmit a value representing a magnitude of the measured pressure variation to a display associated with the extracorporeal blood circuit.

A hemodialysis apparatus comprising diaphragm pumps for the movement of both dialysate and blood, and under the control of a controller, is capable of detecting blood flow conditions that give rise to an alarm and implement procedures to adjust, pause, or halt the pumping of dialysate and/or blood. The controller can direct the application of a time-varying pressure to fluid in the control chamber of a blood pump, and monitor the resulting pressure waveform during a fill stroke of the blood pump. A deviation of the measured pressure variation from an expected value can give rise to an alert to a user and to the initiation of an adjustment, pause, or cessation of the dialysate pump's activity.

A hemodialysis apparatus comprising diaphragm pumps for the movement of both dialysate and blood, and under the control of a controller, is capable of detecting blood flow conditions that give rise to an alarm and implement procedures to adjust, pause, or halt the pumping of dialysate and/or blood. The controller can direct the application of a time-varying pressure to fluid in the control chamber of a blood pump, and monitor the resulting pressure waveform during a fill stroke of the blood pump. A deviation of the measured pressure variation from an expected value can give rise to an alert to a user and to the initiation of an adjustment, pause, or cessation of the dialysate pump's activity.

Hemodialysis and similar dialysis systems including a variety of systems and methods that make hemodialysis more efficient, easier, and/or more affordable, and include new fluid circuits for fluid flow in hemodialysis systems and a reciprocating diaphragm pump for pumping fluids. The reciprocating diaphragm pump includes a flexible diaphragm, a first rigid body having a curved pumping chamber wall, a second rigid body having an opposing curved control chamber wall. The diaphragm is interposed between the pumping chamber wall and the control chamber wall to define a pumping chamber and a control chamber. The diaphragm of the pump has a peripheral bead arranged to locate the diaphragm between the first rigid body and the second rigid body and a diaphragm body having a curved, semi-spheroid or domed shape. The diaphragm is pre-formed or molded so that during a delivery stroke of the pump, the elastic force of the diaphragm resisting its deployment into the pumping chamber prevents a peripheral portion of the diaphragm body from fully contacting the pumping chamber wall.

Hemodialysis and similar dialysis systems including a variety of systems and methods that make hemodialysis more efficient, easier, and/or more affordable, and include new fluid circuits for fluid flow in hemodialysis systems and a reciprocating diaphragm pump for pumping fluids. The reciprocating diaphragm pump includes a flexible diaphragm, a first rigid body having a curved pumping chamber wall, a second rigid body having an opposing curved control chamber wall. The diaphragm is interposed between the pumping chamber wall and the control chamber wall to define a pumping chamber and a control chamber. The diaphragm of the pump has a peripheral bead arranged to locate the diaphragm between the first rigid body and the second rigid body and a diaphragm body having a curved, semi-spheroid or domed shape. The diaphragm is pre-formed or molded so that during a delivery stroke of the pump, the elastic force of the diaphragm resisting its deployment into the pumping chamber prevents a peripheral portion of the diaphragm body from fully contacting the pumping chamber wall.

A pumping cassette including a housing having at least two inlet fluid lines and at least two outlet fluid lines. At least one balancing pod within the housing and in fluid connection with the fluid paths. The balancing pod balances the flow of a first fluid and the flow of a second fluid such that the volume of the first fluid equals the volume of the second fluid. The balancing pod also includes a membrane that forms two balancing chambers. Also included in the cassette is at least two reciprocating pressure displacement membrane pumps. The pumps are within the housing and they pump the fluid from a fluid inlet to a fluid outlet line and pump the second fluid from a fluid inlet to a fluid outlet.

A pumping cassette including a housing having at least two inlet fluid lines and at least two outlet fluid lines. At least one balancing pod within the housing and in fluid connection with the fluid paths. The balancing pod balances the flow of a first fluid and the flow of a second fluid such that the volume of the first fluid equals the volume of the second fluid. The balancing pod also includes a membrane that forms two balancing chambers. Also included in the cassette is at least two reciprocating pressure displacement membrane pumps. The pumps are within the housing and they pump the fluid from a fluid inlet to a fluid outlet line and pump the second fluid from a fluid inlet to a fluid outlet.

A method and apparatus for compressing gases and supplying fuel to a gaseous fuel consuming device, such as a gaseous fueled vehicle or the like. One embodiment includes a gas compressor for compressing the gaseous fuel to an array of tanks having predetermined initial set points which are increasing for tanks in the array. One embodiment provides a selecting valve having first and second families of ports wherein the valve can be operated to select a plurality of ports from the first family to be fluidly connected with a plurality of ports with the second family, and such fluid connections can be changed by operation of the valve.

A method and apparatus for compressing gases and supplying fuel to a gaseous fuel consuming device, such as a gaseous fueled vehicle or the like. One embodiment includes a gas compressor for compressing the gaseous fuel to an array of tanks having predetermined initial set points which are increasing for tanks in the array. One embodiment provides a selecting valve having first and second families of ports wherein the valve can be operated to select a plurality of ports from the first family to be fluidly connected with a plurality of ports with the second family, and such fluid connections can be changed by operation of the valve.

A fluid choke may include a housing and a shuttle configured to move within an interior chamber of the housing. The housing may have a fluid inlet channel and a fluid outlet channel. The shuttle may have a gate connected to an end of the shuttle and the gate may be configured to mate with a seat located in the housing at the fluid outlet channel. The shuttle may be moved within the interior chamber by a pressurized hydraulic fluid configured to apply a hydraulic pressure to a peripheral portion of the shuttle, an inner portion of the shuttle, and the gate.