Thermally responsive valve assembly

Claim 1

A thermally responsive valve assembly comprising: a. a wall member having means defining a flow port therethrough, b. an inner end of said flow part being of substantially reduced diameter, c. an outer end of said flow port being of substantially larger diameter than said inner end thereof, d. means defining internal threads in said flow port at said outer end thereof, e. means defining an inlet extending into said wall member and intersecting said flow port intermediate saiD inner and outer ends thereof, f. a valve member consisting essentially of two elements, g. a first of said two elements consisting of an elongated, cylindrical, thin walled valve shell, h. means defining an unthreaded, substantially smooth surfaced, constant diameter bore extending axially through said shell, i. an outer end of said bore through said shell being substantially larger than the remainder of said bore and defining a shoulder at the intersection of said outer end and said remainder of said bore, j. means defining external threads on the outer surface of said shell complementary to and in engagement with said internal threads, k. the second of said two elements consisting of an elongated unitary, rod-like valve core of relatively rigid polymeric material having a coefficient of linear thermal expansion substantially greater than said shell, l. said core including a central shank portion, an enlarged outer end and a conically shaped inner end, m. the intersection of said shank portion and said enlarged portion of said core defining a shoulder received in overlying relation to said shoulder on said shell, n. means fixing said shoulders in said overlying relationship with said enlarged portion of said core permanently fixed in said outer end of said shell against movement relative thereto, o. said shank portion of said core having a substantially smooth surfaced, unthreaded, outer periphery of substantially constant diameter slidably received in said bore of said core, and p. said conically shaped inner end of said core having at least a portion thereof received within said reduced diameter inner end of said flow port through said wall member, q. whereby thermally induced axial movement of said core within said shell inwardly of said overlying shoulders thereof will cause said conically shaped inner end of said core to move within said reduced diameter inner end of said flow port to vary the effective diameter thereof in response to temperature variations.