An infusion pump apparatus includes a length of resilient tubing removably loadable in an infusion pump having a housing, a pumping mechanism, and a pump door. A latch member is pivotally mounted to the pump door and cooperates with a latch pin fixed on pump housing. A free-flow protection device is biased to pinch the tubing closed to stop fluid flow. The latch member has a first range of pivotal motion in a latching direction for causing the latch member to engage with the latch pin to secure the door in a closed position and a second range of pivotal motion in the latching direction for causing the latch member to actuate the free-flow protection device to unpinch the tubing and allow flow. The latch member pivots through at least a portion of the first range of pivotal motion before beginning to pivot through the second range of pivotal motion.

A drive device is provided comprising a working pump, the working pump connected to a membrane fluid pump, and the working pump having a working piston able to oscillate axially between two reversal points for contracting and expanding a working chamber, and a control unit for controlling a movement of the working piston between the two reversal points. The controlled movement of the working piston comprises three temporally successive phases, in a first phase the working piston is accelerated to a speed that is greater than a speed at the end of the first phase, in a second phase the working piston is moved such that a specified speed of the working piston, a specified relative pressure in the working chamber, or a specified force of the working piston is substantially kept constant, and in a third phase the working piston is moved at a negative acceleration.

The invention relates to valve system for controlling a process fluid within a liquid processing system. The valve system comprises a valve arrangement, a pneumatic control system, and a connector unit. When the valve arrangement is connected to the connector unit, two or more valves are formed, such that the pneumatic control system controls an open/close or pressure control mode of the valves. A pump diaphragm system is disclosed, as well as a system for purifying a biological material that comprises the valve system or the pump diaphragm system. Also discloses are methods of using the valve system or the pump diaphragm system in a process for the purification of a biological material.

A fuel system for providing fuel to a downstream component includes a fuel tank container having a hollow interior for storing a volume of fuel and a fuel line fluidly coupling the hollow interior with the downstream component. A first end of the fuel line is arranged within the hollow interior such that a fuel pick-up location is defined between the first end of the fuel line and an adjacent surface of the fuel tank container. A sump pad is positioned within the hollow interior. The sump pad is transformable between a deflated configuration and an inflated configuration to direct fuel within the hollow interior toward the fuel pick-up location.

A fluid-driven chemical product dispensing system dispenses fluid chemical product concentrates. The dispensing system includes a fluid drive unit powered by flow of a fluid, such as a diluent, and a pump which delivers the fluid chemical product concentrate from a supply to a destination. Upon exit from the fluid drive unit, the diluent is also delivered to the destination, where it mixes with the dispensed fluid chemical product concentrate to form a use solution. The dilution ratio of the volume of fluid chemical product concentrate dispensed per unit time versus the volume of diluent exiting the drive unit per unit time is constant over a defined range of diluent flow rates.

The present invention relates to a dosing mechanism including: a body; and a pump unit (3) that is attached to the body, in which the pump unit (3) includes: a pump (31) in which a volume of a solution feeding part therein repeats expansion and shrinkage, thereby sucking a medicine from a medicine vessel and discharging the medicine to a patient; a suction-side pipe (333) that extends from the pump (31) toward the medicine vessel; a discharge-side pipe (343) that extends from the pump (31) toward the patient; a relief pipe (35, 35a) whose one end (351) is connected to the discharge-side pipe (343) while the other end (352) is located in a part whose pressure is lower than pressure inside the discharge-side pipe when the medicine is dosed; and a relief pipe on-off valve (36, 36a) that opens and closes the relief pipe (35, 35a), a use method of a dosing mechanism, and a pump unit for a dosing mechanism.

A positive displacement pump includes two fluid flow paths, two center sections with a common fluid valve, a changeover valve, and three fluid displacement members. Each center section contains a diaphragm shaft, and the two sections are separated by the third diaphragm. In low-pressure mode the pump operates as a typical positive displacement pump with pumping fluid supplied to one center section and the changeover valve allowing the fluid to freely circulate within the second center section. In high-pressure mode, the changeover valve is switched and the changeover valve allows the common fluid valve to supply pumping fluid to both center sections to drive the fluid displacement members therein, which generates a higher outlet fluid pressure.

The invention relates to a positive displacement pump 1 for conveying medical fluids, which pump has a pumping chamber 5 and a positive displacement element 15, and to a blood treatment apparatus comprising a positive displacement pump 1. In addition, the invention relates to a method for controlling a positive displacement pump 1 for conveying medical fluids. The positive displacement pump 1 according to the invention has an actuation member 20 in operative connection with the positive displacement element 20 for displacing or deforming the positive displacement element in order to convey the fluid into the pumping chamber or out of the pumping chamber, and a drive device 21 for displacing the actuation member 20. A control unit 14 is provided for to controlling the drive device 21 and an inlet valve 12 and outlet valve 13. The actuation member 20 is in operative connection with the positive displacement element 15 via a working chamber 19 that is filled with gas and has a sealed volume. In order to achieve a high conveying precision, the pressure in the working chamber 5 is kept constant when the positive displacement element 15 is moved.

An electronically controlled diaphragm pump system includes a pump housing with a drive gas chamber, a fluid chamber separated by a diaphragm, gas pressure means for providing a drive gas pressure in response to a control signal, and gas under-pressure means connected to a gas outlet port for providing a gas outlet under-pressure or sucking of gas in response to a control signal. The pump system has a displacement sensor and control circuitry connected to the displacement sensor for determining the displacement or position of the diaphragm and adapted or supplying the control signals to the gas pressure means and the gas under-pressure means.

Various systems and methods for detecting air in a chamber of an infusion system are disclosed. In one embodiment, a determination is made that air is contained in the chamber on the basis of a change in the average force exerted against the plunger utilizing a derivative spike for event detection and a systematic reduction in the average force to confirm the nature of the change. In another embodiment, a determination is made that the chamber contains air when a difference between the current force profile and a baseline force profile crosses a threshold. In an additional embodiment, a force profile is classified as being an air force profile or a liquid force profile based on extracted features of the force profile.