Abstract: A thermal actuator of the expansible wax type is disclosed having an actuator rod extending through an enlarged clearance hole in an upper guide casing, a closely fitting hole in a guide washer, and a snugly fitting anti-chafe ring. The washer and ring are located intermediate the upper surface of a flexible diaphragm and a counterbore defined by the guide casing. The clearance between the outer diameter of the guide washer and the counterbore formed by the guide casing is substantially less than the clearance between the guide casing opening and the actuator rod. The guide washer and anti-chafe ring mounting arrangement in relation to the guide casing opening provides improved rod alignment and a self-cleaning action as the rod moves.

Abstract: A valve assembly of the type providing bypass flow through a branch channel when the movable valve member is in the closed position to block flow through the main flow channel outlet. A venturi device is disposed in the main channel upstream of the movable valve member, and the venturi has secondary ports provided through the wall at the throat section. When the movable valve member is in the closed position, flow into the venturi exits at the flow ports and flows through the bypass channel. When the movable valve member is in the open position, flow discharges from the venturi, through the main channel outlet port downstream of the movable valve member, thereby causing reduced pressure at the venturi throat and preventing flow through the secondary ports to the bypass channel.