Three port thermal vacuum valve with electrical switch

Abstract From the Canadian patent

A thermally responsive device for valving a common fluid signal port between two separate fluid pressure sources and simultaneously actuating an electrical switching means. The electrical switching means is isolated from the fluid valving means and pressure ports. A thermal sensing means is operative in response to predetermined temperatures to move a valve means for valving the common signal port between the separate fluid pressure sources. The valve means employs a unitary valve member having spaced seals for seating against individual valve seats for alternately isolating the individual pressure source ports from the signal port.