Automatic drain trap

Abstract

An automatic drain system is provided for reservoirs used to accumulate water, condensables, and other foreign materials which may be present in pneumatic systems and the like. This drain system is associated with a reservoir wherein these contaminants are accumulated and is operated by a float within this reservoir. The principal operating items of the drain system are a pair of magnetically coupled magnets, one positioned within the float and the other within a valve plug of a pilot valve. These magnets normally have opposite polarities whereby the float, in its lowest position and as it rises within the reservoir, causes the valve plug to be maintained against the pilot valve seat. A separate pneumatic system attached to this pilot valve maintains a drain valve operator in a condition such that the drain valve from the reservoir is closed while the pilot valve components are in contact. When the float reaches its uppermost position, the magnet therein brings about an effective reversal of the polarity of the magnet in the valve plug causing the valve plug to be moved away from the pilot valve seat. When this occurs, the drain valve operator is moved in a direction such that the drain valve is rapidly opened permitting the complete draining of any material accumulated in the reservoir. When the float reaches its most downward position, the polarity of the magnet within the pilot valve plug is again effectively reversed and the pilot valve is closed to again close the drain valve.