A rotary pump for a fluid metering system is provided. The rotary pump reciprocates, and is reversed by a signal from a limit switch that is deflected by an actuator arm on a rotating sleeve of the pump system.

A rotary sub-assembly for pumping of fluid is provided. The sub-assembly includes a hollow body defining a cavity having a longitudinal axis, the body comprising a cavity wall with at least two ports passing therethrough. At least a portion of the cavity has a non-circular cross-section such that a first constant or varying radial distance from the longitudinal axis to inwardly-offset segments of the cavity wall surrounding the two ports is less than a second constant or varying radial distance from the longitudinal axis to second segments of the cavity wall spaced apart from the two ports. A rotatable plunger is housed in the cavity. The plunger is sized and shaped such that a side wall of the plunger can establish a liquid-tight seal against the inwardly-offset segments of the cavity wall, but does not establish a liquid-tight seal with the second segments of the cavity wall spaced apart from the two ports.

A rotary sub-assembly for pumping of fluid is provided. The sub-assembly includes a hollow body defining a cavity having a longitudinal axis, the body comprising a cavity wall with at least two ports passing therethrough. At least a portion of the cavity has a non-circular cross-section such that a first constant or varying radial distance from the longitudinal axis to inwardly-offset segments of the cavity wall surrounding the two ports is less than a second constant or varying radial distance from the longitudinal axis to second segments of the cavity wall spaced apart from the two ports. A rotatable plunger is housed in the cavity. The plunger is sized and shaped such that a side wall of the plunger can establish a liquid-tight seal against the inwardly-offset segments of the cavity wall, but does not establish a liquid-tight seal with the second segments of the cavity wall spaced apart from the two ports.

A rotary pump for a fluid metering system is provided. The rotary pump reciprocates, and is reversed by a signal from a limit switch that is deflected by an actuator arm on a rotating sleeve of the pump system.

A rotary pump for a fluid metering system is provided. The rotary pump reciprocates, and is reversed by a signal from a limit switch that is deflected by an actuator arm on a rotating sleeve of the pump system.

A rotary sub-assembly for pumping of fluid is provided. The sub-assembly includes a hollow body defining a cavity having a longitudinal axis, the body comprising a cavity wall with at least two ports passing therethrough. At least a portion of the cavity has a non-circular cross-section such that a first constant or varying radial distance from the longitudinal axis to inwardly-offset segments of the cavity wall surrounding the two ports is less than a second constant or varying radial distance from the longitudinal axis to second segments of the cavity wall spaced apart from the two ports. A rotatable plunger is housed in the cavity. The plunger is sized and shaped such that a side wall of the plunger can establish a liquid-tight seal against the inwardly-offset segments of the cavity wall, but does not establish a liquid-tight seal with the second segments of the cavity wall spaced apart from the two ports.

A rotary sub-assembly for pumping of fluid is provided. The sub-assembly includes a hollow body defining a cavity having a longitudinal axis, the body comprising a cavity wall with at least two ports passing therethrough. At least a portion of the cavity has a non-circular cross-section such that a first constant or varying radial distance from the longitudinal axis to inwardly-offset segments of the cavity wall surrounding the two ports is less than a second constant or varying radial distance from the longitudinal axis to second segments of the cavity wall spaced apart from the two ports. A rotatable plunger is housed in the cavity. The plunger is sized and shaped such that a side wall of the plunger can establish a liquid-tight seal against the inwardly-offset segments of the cavity wall, but does not establish a liquid-tight seal with the second segments of the cavity wall spaced apart from the two ports.

A pump for the pumping small volumes of medical fluid is provided. The pump has a manifold chamber having an inlet port and an outlet port. Within the manifold chamber, a cannula having input and output holes oriented with respect to the inlet and outlet ports is rotated within the manifold chamber, and translated axially in a reciprocating manner. The input opening of the cannula overlaps with the inlet port as the manifold chamber volume is increasing to draw fluid into the manifold chamber from the input port. The output opening of the cannula chamber overlaps with the output port as the manifold chamber volume is decreasing to force fluid out of the manifold chamber to the outlet port. The cannula may be formed from metal needle stock.

A pump for the pumping small volumes of medical fluid is provided. The pump has a manifold chamber having an inlet port and an outlet port. Within the manifold chamber, a cannula having input and output holes oriented with respect to the inlet and outlet ports is rotated within the manifold chamber, and translated axially in a reciprocating manner. The input opening of the cannula overlaps with the inlet port as the manifold chamber volume is increasing to draw fluid into the manifold chamber from the input port. The output opening of the cannula chamber overlaps with the output port as the manifold chamber volume is decreasing to force fluid out of the manifold chamber to the outlet port. The cannula may be formed from metal needle stock.

A rotary pump for a fluid metering system is provided. The rotary pump reciprocates, and is reversed by a signal from a limit switch that is deflected by an actuator arm on a rotating sleeve of the pump system.