Intravenous metering device

Claim 1

A device for the precise metering of liquids for intravenous delivery to a patient, said device comprising a substantially rigid shell forming a pumping chamber, said chamber having an upper wall with first, second and third openings therein, a first resilient diaphragm covering said first opening and being adapted to be selectively engaged by an actuator member to move it from a relaxed position to a stressed position extending into the pumping chamber, means forming an inlet port for admitting liquid into said pumping chamber, said inlet port being positioned generally parallel to and closely spaced from said diaphragm in its relaxed position so that when said diaphragm is moved into its stressed position by said actuator member it will seal said inlet port to prevent the flow of liquid therethrough, said chamber having an outlet port spaced below the inlet port for the discharge of liquid from the chamber, an outlet valve for closing said outlet port including means for biasing said valve in its closed position with a predetermined biasing pressure, a second resilient diaphragm positioned to cover said second opening in said wall and adapted to be engaged by a piston to cause it to be extended into said chamber to create a pressure within the chamber capable of overcoming the biasing pressure to permit the discharge of liquid from the chamber, and a third diaphragm covering the third opening and having a projecting portion depending therefrom, said third opening being located above said outlet port whereby a projection member may be arranged to engage said third diaphragm within said third opening to cause the projecting portion thereof to engage the outlet valve to open said outlet port and permit the filling of the device and the tubing downstream thereof with liquid.

Claim 2

A device for the precise metering of liquids for intravenous delivery to a patient, said device comprising a substantially rigid shell forming a pumping chamber, said chamber having an upper wall with first, second and third openings therein, a first resilient diaphragm covering said first opening and being adapted to be selectively engaged by an actuator member to move it from a relaxed position to a stressed position extending into the pumping chamber, means forming an inlet port for admitting liquid into said pumping chamber, said inlet port being positioned generally parallel to and closely spaced from said diaphragm in its relaxed position so that when said diaphragm is moved into its stressed position by said actuator member it will seal said inlet port to prevent the flow of liquid therethrough, said chamber having an outlet port spaced below the inlet port for the discharge of liquid from the chamber, an outlet valve for closing said outlet port including means for biasing said valve in its closed position with a predetermined biasing pressure, a second resilient diaphragm positioned to cover said second opening in said wall and adapted to be engaged by a piston to cause it to be extended into said chamber to create a pressure within the chamber capable of overcoming the biasing pressure to permit the discharge of liquid from the chamber, and a third diaphragm covering the third opening and having a projecting portion depending therefrom, said third opening being located above said outlet port whereby a projection member may be arranged to engage said third diaphragm within said third opening to cause the projecting portion thereof to engage the outlet valve to open said outlet port and permit the filling of the device and the tubing downstream thereof with liquid.