Diaphragm seal with fluid filled cavity for paddle or fluid flow responsive switch

Claim 1

A flow switch responsive to fluid flow variations within a conduit, comprising a body secured to the conduit about an opening communicating with the conduit interior, the body having a cavity extending from the opening in generally perpendicular relation to fluid flow within the conduit, a tubular portion of the body surrounding the cavity extending into the conduit opening, an elongated member arranged within the cavity, the member including a paddle arranged within the conduit for reaction to fluid flow therein, means for pivoting the member upon the body adjacent the opening in the conduit, an elastomeric diaphragm secured in sealed relation to the member adjacent the pivot and extending radially outwardly to overlap an end of the tubular body portion, the elongated member having an enlarged portion adjacent the pivot and a spaced apart seal retaining element, the enlarged portion and seal retaining element forming facing annular grooves, the diaphragm having a bead which tends to be compressed into the facing grooves, a cup-shaped seal retainer for compressing the diaphragm against the end of the tubular body portion, the seal retainer having a flange extending radially outwardly from the opening between the conduit and flow switch body, an electrical contact supported on the switch body adjacent an electrical point supported on an end of the member within the cavity, an adjustable stop penetrating the switch body for limiting movement of the member away from the electrical contact, spring means supported by the body for resisting movement of the member, and means for interconnecting the electrical contact and electrical point on the member with a warning circuit.