Dual bimetal relief valve

DETAILED DESCRIPTION In an adapter unit to be disposed between an external filter unit and a fluid reservoir there are provided dual thermostatic pressure relief valves operated by a single valve gate.
The adapter unit comprises a body member having an interior recess with two closely spaced inlet ports, the ports having opposing valve seats.
A curved bimetal leaf of approximately three-quarters of a full circle is disposed in the recess and anchored at one end to the body member.
The free end of the leaf is operative as a double valve gate for alternately opening and closing the opposing ports.
In particular, the leaf is a bimetal element with a reversal of high expansion and low expansion sides at a preselected point at approximately one-third of its length from the anchor point.
In a specific embodiment, the first portion of the leaf between the anchor and the preselected point has the low expanding side of the bimetal element radially outwardly disposed relative to the high expanding side, and in the portion between preselected point and the free end, the low expanding side is radially inwardly disposed relative to the high expanding side.
A preferred semicircular shape of the bimetal element is such as to cause a substantially linear displacement of the free end between the opposing valve seats with a force sufficient to close off the valves completely and throw sufficient to fully open the valves to minimize excess pressure differential across the ports.
Moreover, the leaf is also operative as a pressure relief valve gate in the event of excess forward differential pressure across a closed valve.
In one specific application, the dual valves are incorporated within a relatively thin cylindrical adapter which couples between a spin-on type oil filter unit and its connection in an engine lubricating circuit.
The valves are operative to direct flow of lubricating fluid through a cooling radiator whenever the temperature of the fluid exceeds a first predetermined temperature level, and the valves are further operative to cut off flow of lubricating fluid through the cooling radiator whenever the fluid temperature and pressure are below selected levels