Magnetically-operated valve

A valve adapted to be mounted on a cylinder containing a liquid and operable to prevent such liquid contents from being totally withdrawn from said cylinder, comprising:

• a body adapted to be mounted on said cylinder and having a passageway for permitting flow of gas therethrough and having a seat surrounding said passageway;
• an element mounted in said body for movement toward and away from said seat, said element having a portion thereof arranged to sealingly engage said seat when said element is moved selectively toward said seat and having a magnetic pole;
• a magnet mounted in said body for movement between a first position at which said element pole will be proximate the opposite pole of said magnet for causing said element to be moved away from said seat, and a second position at which said element pole will be proximate the like pole of said magnet for causing said element to be moved toward said seat;
• an actuator arranged to move said magnet in response to variation in the level of said liquid within said cylinder, said actuator including a float arranged to sense the level of said liquid, and a rod connecting said float and magnet, said magnet being mounted for movement within said body in a direction substantially perpendicular to the direction of movement of said element;
• and
• an override mechanism mounted on said body and selectively operable to displace said element away from said seat when said magnet is in said second position to permit flow of fluid through said passageway.