Heat exchanger with temperature responsive bypass

Claim 1

A heat exchanger for exchanging heat between first and second liquids, comprising: a plurality of successive heat exchange units each including first and second plates joined together at peripheral edges to define therebetween a first chamber for said first liquid; a casing having inlet and outlet means for said second liquid and enclosing said plurality of heat exchange units; means for arranging said heat exchange units in a spaced sequence of successive heat exchange units in said casing to provide a second chamber for said second liquid between each pair of said heat exchange units and also for separating said first chambers from said second chambers; means defining an inlet opening through said casing for introducing said first liquid into one of said heat exchanger units; means defining first successive flow openings through said successive heat exchange units in said sequence, said first flow openings communicating with one another and communicating with said inlet opening and said first chambers to permit flow of said first liquid into said first chambers; means defining a bypass opening through which said first liquid is dischargeable from said heat exchange units, said bypass opening communicating with said first flow openings to provide a direct flow path from said inlet opening; and an oil temperature responsive bypass valve which opens to allow said first liquid to flow through said bypass opening when the temperature of said first liquid is below a predetermined level, said oil temperature responsive bypass valve including a helical bimetal element having a first end, and a second end provided with a valve flap, a support member to which said bimetal element is suported at the first end, said support member having first and second leg plate sections, each leg plate section being curled at one end portion thereof to form a straight extending proper part and a curled end part which is generally parallel with said proper part and said one curled end part being formed at its upper surface with a projection, and a base plate member secured to a part of said casing and being formed with first and second bent sections each of which defines thereinside a tunnel in which said one end portion of said support member leg plate section is insertable, each of first and second bent sections being formed with a hole into which said projection of said curled end part of each leg plate section is insertable, said base plate member being formed with a discharge opening communicating with said bypass opening, said discharge opening being closable with said valve flap of said bimetal at temperatures of said first liquid in which cooling of said first liquid is required.