Check valve for use with intravenous pump

Claim 2

A check valve for incorporation into a liquid supply system for preventing flow from a location in the system downstream from the check valve to a location upstream from the check valve when the downstream pressure is greater than the upstream pressure by no more than a selected value, the check valve comprising: a housing configured to be disposed in the system between an upstream liquid source and a downstream portion of the system; a valve seat disposed in the housing; a valve member disposed in the housing having an upstream-facing surface and a downstream-facing surface; and means in the housing for supporting the valve member downstream from the valve seat when the upstream pressure is greater than the downstream pressure, the valve member being movable to the valve seat for preventing flow in an upstream direction through the check valve when the downstream pressure is greater than the upstream pressure by no more than a selected value, the valve member including means for relieving downstream pressure when the downstream pressure exceeds the upstream pressure by the selected value.

Claim 3

The check valve according to claim 1 wherein the valve member comprises a resilient material, and the pressure-relieving means comprises a slit through the valve member extending from its upstream-facing surface to its downstream-facing surface.

Claim 4

The check flow valve according to claim 1 wherein the valve member comprises a rubber disc having a slit through about its center extending from its upstream-facing surface to its downstream-facing surface.

Claim 5

The check flow valve according to claim 1 wherein the housing comprises: a lower housing member and an upper housing member, the upper housing member having a tubular adapter at its upstream end and a valve seat proximate its downstream end, the upper housing member being telescopically inserted into the lower housing member, wherein the lower housing member has a tubular adapter at its downstream end, wherein the valve member support means are proximate the upstream end of the lower housing member and comprise a plurality of projections, and wherein the valve member comprises a flexible disc, having a slit therethrough, extending from its upstream-facing surface to its downstream-facing surface, the valve member being positioned between the upper and lower housing members such that the valve member abuts the projections when the check valve is open and abuts the valve seat when the check valve is closed.

Claim 6

The valve member according to claim 1 wherein the selected pressure value is from about 40 inches to about 75 inches of water pressure.

Claim 7

The valve member according to claim 1 wherein the selected pressure value is about 45 inches of water pressure.

Claim 8

In a check valve for preventing liquid flow from downstream thereof to upstream thereof when the downstream pressure is greater than the upstream pressure by no more than a selected value, the check valve comprising a flexible valve disc, a housing comprising a lower housing member connected to an upper housing member, wherein the lower housing member includes means for supporting the valve disc when the valve is open, to thereby permit liquid flow from upstream thereof to downstream thereof and wherein the upper housing member includes a valve seat for engaging the valve disc when the valve is closed, the improvement comprising means formed in the valve disc for relieving downstream pressure when the downstream pressure exceeds the upstream pressure by the selected value.

Claim 9

In a check valve for preventing liquid flow from downstream thereof to upstream thereof when the downstream pressure is greater than the upstream pressure by no more than a selected value, the check valve comprising a flexible valve disc, a housing comprising a lower housing member connected to an upper housing member, wherein the lower housing member includes means for supporting the valve disc when the valve is open, to thereby permit liquid flow from upstream thereof to downstream thereof and wherein the upper housing member includes a valve seat for engaging the valve disc when the valve is closed, the improvement comprising means formed in the valve disc for relieving downstream pressure when the downstream pressure exceeds the upstream pressure by the selected value.

Claim 10

The check valve according to claim 7 wherein the valve disc is formed of a resilient material, and the pressure-relieving means comprises a slit through the disc.

Claim 11

The check valve according to claim 8 wherein the valve disc is formed of rubber, and the slit is through the disc at about its center.

Claim 12

The check valve according to claim 7 wherein the lower housing member has a tubular adapter at its downstream end, the valve disc support comprises a plurality of projections connected to the lower housing member, with the ends of the projections extending toward its upstream end, wherein the upper housing member is telescopically inserted into the lower housing member and wherein the upper housing member has a tubular adapter at its upstream end and the valve seat is formed integrally with the upstream member proximate its downstream end, the valve disc comprising a flexible material having a slit therethrough and being located between the upper and lower housing members such that the valve disc abuts the plurality of projections when the valve is open, thereby permitting liquid to flow from upstream of the check valve to downstream thereof and such that the valve disc abuts the valve seat when the valve is closed.

Claim 13

The check valve according claim 7 wherein the selected pressure value is from about 40 inches to about 75 inches of water pressure.

Claim 14

The valve member according to claim 7 wherein the selected pressure value is about 45 inches of water pressure.

Claim 15

A medical liquid administration set for administering first and second liquids to a patient comprising: a first liquid source; a second liquid source; connector means for combining two flows into one flow; first conduit means for connecting the first liquid source to the connector means; second conduit means for connecting the second liquid source to the connector means; third conduit means for connecting the one flow from the connector means to the patient; means disposed along a path of the third conduit means for pumping liquids from the first and second liquid sources to the patient; and a check valve disposed along a path of the first conduit means for preventing liquid flow from downstream of the check valve to upstream thereof when the downstream pressure is greater than the upstream pressure by no more than a selected value, the check valve comprising a housing, a valve seat disposed in the housing, a valve member disposed in the housing having an upstream-facing surface and a downstream-facing surface, means in the housing for supporting the valve member downstream from the valve seat when the upstream pressure is greater than the downstream pressure, the valve member being movable to the valve seat for preventing flow in an upstream direction through the check valve when the downstream pressure is greater than the upstream pressure by no more than a selected value, the valve member including means for relieving downstream pressure when the downstream pressure exceeds the upstream pressure by the selected value.

Claim 16

A medical liquid administration set for administering first and second liquids to a patient comprising: a first liquid source; a second liquid source; connector means for combining two flows into one flow; first conduit means for connecting the first liquid source to the connector means; second conduit means for connecting the second liquid source to the connector means; third conduit means for connecting the one flow from the connector means to the patient; means disposed along a path of the third conduit means for pumping liquids from the first and second liquid sources to the patient; and a check valve disposed along a path of the first conduit means for preventing liquid flow from downstream of the check valve to upstream thereof when the downstream pressure is greater than the upstream pressure by no more than a selected value, the check valve comprising a housing, a valve seat disposed in the housing, a valve member disposed in the housing having an upstream-facing surface and a downstream-facing surface, means in the housing for supporting the valve member downstream from the valve seat when the upstream pressure is greater than the downstream pressure, the valve member being movable to the valve seat for preventing flow in an upstream direction through the check valve when the downstream pressure is greater than the upstream pressure by no more than a selected value, the valve member including means for relieving downstream pressure when the downstream pressure exceeds the upstream pressure by the selected value.

Claim 17

The administration set according to claim 13 wherein the valve member comprises a resilient material, and the pressure-relieving means comprises a slit through the valve member extending from its upstream-facing surface to its downstream-facing surface.

Claim 18

The administration set according to claim 13 wherein the valve member comprises a rubber disc with a slit through about its center extending from its upstream-facing surface to its downstream-facing surface.

Claim 19

The administration set according to claim 13 wherein the housing comprises upper and lower housing members, the valve member support means comprising a plurality of projections connected to the lower housing member, the valve seat being formed integrally with the upper housing member proximate its downstream end, wherein the lower housing member has a tubular adapter at its downstream end and the upper housing member has a tubular adapter at its upstream end, the upper housing member being telescopically inserted into the lower housing member, wherein the valve member comprises a flexible sheet having a slit therethrough and is situated between the upper and lower housing members such that the valve member abuts the projections when the valve is open and abuts the valve seat when the valve is closed.

Claim 20

The administration set according to claim 13 wherein the selected pressure value is about 40 inches to about 75 inches of water pressure.

Claim 21

The administration set according to claim 13 wherein the selected pressure value is about 45 inches of water pressure.