Compensating joint for high temp line - having outer sleeve with inner collar and provision for cooling

Compensator for high temp. lines constructed from outer shell and inner refractory cladding, consists of outer sleeve joined to pipe shell with butt joint between the two pipe sections. Inner cylindrical collars from part of the joint. At either end is an annular distributor on the inside of the sleeve to distribute coolant. Beneath this is a collar, the dia. of which is smaller than the outer sleeve. Two rings then form the distributor channels. The outer rings are tightly sealed to the sleeve and inner collar. The inner ones form passages from the distribution channels to the annular space between the outer sleeve and the inner collar. This permits the passage of coolant between inlet and outlet branches on the distribution channels through the annular gap below the ribbed outer sleeve. System is esp. for use on the air feed lines to blast furnaces where the air temp. is 1200-1400 degrees C severe thermal stresses are caused by a rise in temp. from ambient to 1400 degrees C.