US 7,338,475 B2Granted

Electret enhanced automatic IV drip chamber shutoff

AssigneeCardinal Health 303, Inc.

InventorHouston Brown

Life of this patent

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Abstract

An automatic stop valve formed in a container of a medical fluid administration system includes an electrical field that attracts the float and valve seat together to shut off flow from the exit port of the container when the fluid within the container is reduced to a predetermined level. One or both of the float and valve seat creates an electric field that attracts the other, which is made of a non-magnetic dielectric, into engagement. In one embodiment, the valve seat is formed of an electret that creates the electric field attracting the float to it to stop flow. In another embodiment, the float comprises an electret that attracts the float to the dielectric valve seat. In yet another embodiment, both the float and valve seat include electrets of opposite polarity that attract each other into engagement. The lack of magnetic and metallic materials makes the shut off valve suitable for use in an MRI environment.

Claims24

Dependent claims

An automatic shut off valve for use in regulating the flow of medical fluid from a medical fluid source, comprising:

a container configured to operate in an upright position and to contain a varying level of medical fluid received from the medial fluid source and an amount of air above the received medical fluid, the container having an upstream end, a downstream end disposed below the upstream end, and an exit orifice formed at the downstream end through which the medical fluid exits the container, the upstream end and the exit orifice configured so that the received medical fluid will fill the container to a normal operating fluid level during the time that the medical fluid source contains medical fluid, and further configured so that the medical fluid in the container will decrease below the normal operating level during the time that the medical fluid source contains no further medical fluid;
a valve seat disposed adjacent the exit orifice at the downstream end of the container and formed of a non-magnetic and dielectric material;
and
a stop member disposed and freely movable within the container having a buoyancy with which the stop member floats at the surface of the medical fluid in the container, the stop member being spaced apart from the valve seat when the medical fluid in the container has the normal operating level, the stop member formed of a non-magnetic and dielectric material;
wherein at least one of the stop member and the valve seat comprises an electrical charge creating an electric field that attracts the other of the stop member and the valve seat and tends to move the stop member into sealing engagement with the valve seat to seal against fluid flow through the exit orifice;
wherein the electric field has a strength selected such that, when the medical fluid in the container reaches a selected level that is more than empty but less than the normal operating level, the electric field overcomes the buoyancy of the stop member to move the stop member into sealing engagement with the valve seat, thereby preventing air above the medical fluid from flowing through the exit orifice.

3 more elements

A method of automatically shutting off flow of medical fluid from a container having an upstream end and a downstream end with an exit orifice and a valve seat at the downstream end and a float located within the container that has sufficient buoyancy to float in the medical fluid and having a size selected to stop flow through the exit orifice when fully engaged with the valve seat, said method comprising:

producing a non-magnetic electrical field from at least one of the float and the valve seat;
forming both the float and the valve seat from a non-magnetic dielectric material that is attracted by the electrical field;
filling the container with medical fluid to a normal operating level with air above the medical fluid at which normal operating level the float floats at a position away from the valve seat and is therefore not engaged with the valve seat;
reducing the medical fluid in the container to a selected level that is more than empty and less than the normal operating level;
and
when the medical fluid reaches the selected level, overcoming the buoyancy of the float by the attraction created with the electrical field so as to cause the float to be fully engaged with the valve seat thereby shutting off flow of the medical fluid through the exit orifice and preventing the air above the medical fluid from flowing through the exit orifice.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/016,280Filed 17 Dec 2004
Published: US 2006/0135939 A122 Jun 2006
Granted: 4 Mar 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

A61M 5/40
With means for eliminating or preventing injection or infusion of air into body: using low-level float-valve to cut off media flow from reservoir
A61M 5/1411
Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor: drip chambers
A61M 2205/0288
Electro-active or magneto-active materials: electro-rheological or magneto-rheological materials
A61M
Devices for delivering substances into the body