Magnetic automatic stop valve

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

• a container adapted to contain medical fluid, the container having an upstream end and a downstream end and defining an exit orifice at the downstream end;
• a hollow float defining an internal post, the float disposed within the container, wherein the float comprises two substantially identical halves joined together to form the float, each float half including a half of the post such that when the substantially identical float halves are joined together, the entire internal post is formed;
• a first attraction element disposed within the float and disposed over the post and adapted to slide along the post;
• and
• a second attraction element disposed at the exit orifice, the first and the second attraction elements being formed of materials that produce magnetic attraction between the two elements;
• wherein the materials that produce the magnetic attraction between the two elements are selected so that the strength of the magnetic attraction between the two elements is such that when the fluid in the container falls to a level near depletion, the first and second attraction elements are attracted to each other with sufficient force to move the float into a position that seals the downstream end against fluid flow;
• wherein the float is generally cylindrical with a larger diameter cylindrical section located at a longitudinal center of the float;
• the float includes opposing ends;
• and
• the first attraction element is disposed over the post such that it may freely slide along the post towards each of the opposing ends;
• whereby the float may be inserted into the container with either of the opposing ends facing the exit orifice at the downstream end of the container and the first attraction element will slide along the internal post towards the second attraction element to establish a magnetic interaction with the second attraction element.

A method of automatically shutting off the flow of medical fluid from a container having an upstream end and a downstream end and defining an exit orifice at the downstream end, said method comprising:

• disposing a first attraction element over a post disposed within a hollow float so that the first attraction element may slide freely along the post;
• disposing a second attraction element at the exit orifice, the first attraction element and the second attraction element being formed from materials that produce magnetic attraction between the two elements;
• and
• inserting the float into the container so that, when fluid in the container falls to a level near depletion, the first and second attraction elements are attracted to each other with sufficient force to move the float into a position that seals the downstream end to fluid flow.