Abstract: A valve system to control administration of fluids from an infusion pump to a patient when the height of the pump relative to the patient is varied, the system comprises a valve which pinches closed the flexible disposable tube that communicates between the pump and the patient unless a minimum pressure is attained in the pump's fluid reservoir. Once the minimum pressure is reached the valve stays open until the pressure in the reservoir drops below a predetermined value which is lower than the minimum "open" pressure. The pressure of the fluid is measured by a sensor pressed against the outside of the reservoir and the valve closes the tube only by externally forcing one external wall against the opposite wall and does not contact the fluid.

Abstract: A valve system to control administration of fluids from an infusion pump to a patient when the height of the pump relative to the patient is varied. The system comprises a valve which pinches closed the flexible disposable tube that communicates between the pump and the patient unless a minimum pressure is attained in the pump's fluid reservoir. Once the minimum pressure is reached the valve stays open until the pressure in the reservoir drops below a predetermined value which is lower than the minimum "open" pressure. The pressure of the fluid is measured by a sensor pressed against the outside of the reservoir and the valve closes the tube only by externally forcing one external wall against the opposite wall and does not contact the fluid.

Abstract: A valve system to control administration of fluids from an infusion pump to a patient when the height of the pump relative to the patient is varied. The system comprises a valve which pinches closed the flexible disposable tube that communicates between the pump and the patient unless a minimum pressure is attained in the pump's fluid reservoir. Once the minimum pressure is reached the valve stays open until the pressure in the reservoir drops below a predetermined value which is lower than the minimum "open" pressure. The pressure of the fluid is measured by a sensor pressed against the outside of the reservoir and the valve closes the tube only by externally forcing one external wall against the opposite wall and does not contact the fluid.

Abstract: A positive displacement infusion pump for delivery of intravenous fluid at a predetermined rate from a standard, flexible intravenous bag to a patient. The pump includes a bag chamber with a moveable side opposing a stationary side. The bag chamber has a volume which is greater that of the bag so the bag may be easily inserted into the chamber. The moveable side is controlled such that adjustments are made to the reduction of the chamber volume and/or rate of reduction of the chamber volume to precisely control the fluid flow out of the bag in accordance with information in the computer memory.

Abstract: A method of pumping fluid from an IV bag with a volumereducible chamber capable of holding the bag. The method includes the steps of placing the bag in the chamber and reducing the volume of the chamber according to calculations from known values in the controller memory to compensate for the nonlinear relationship between the reduction of bag volume corresponding to reduction in chamber volume. The next step is actuating the motor which controls the volume to reduce the volume of the chamber according to the calculations. A method of pumping from a flexible bag also is contemplated where the controller also or alternatively controls the rate of the reduction of the chamber rather than the volume.