Regenerative heat exchanger and method for purging its flow passages

Claim 1

A regenerative heat exchanger for removing heat from a relatively hot dust-laden gas exhausted from a steel converter or the like, the heat exchanger comprising in combination: a. a generally vertical housing provided with an upstream chamber, a downstream chamber and a heat-storage section disposed between said upstream and downstream chambers, said heat-storage section being provided with a plurality of flow passages lined with a heat-storing material, the flow passages connecting said upstream downstream chambers in flow communication each with the other; b. an inlet port in said housing in flow communication with said upstream chamber and connectable in flow communication with a steel converter or the like to receive the hot dust-laden gas therefrom for passage through the heat-storage section wherein the dust-laden gas is cooled and passed thence to said downstream chamber; c. an outlet port in said housing in flow communication with said downstream chamber and connectable to a dust-removal apparatus for delivering the cooled dust-laden gas thereto; d. a blower port in said housing in flow communication with said downstream chamber; e. a blower associated with said blower port for delivering cooling air to said downstream chamber for passage through the flow passages to said upstream chamber; f. an exhausT port in said housing in flow communication with said upstream chamber and heaving a lid openable to permit cooling air to exit from said upstream chamber through said exhaust port; g. a partition wall mounted in said downstream chamber to subdivide that chamber into a first compartment and a second compartment, each connecting the blower port in flow communication with the outlet port; h. first and second blower semidampers mounted in said blower port in flow communication with said first and second compartments, respectively, to control delivery of the purge air thereto; i. first and second outlet semidampers mounted in said outlet port in flow communication with said first and second compartments, respectively, to control exit of the purge air therefrom, whereby said first compartment is in flow communication with a first portion of the flow passages and said second compartment is in flow communication with a second portion of the flow passages so that on opening said first blower semidamper, closing said second blower semidamper, closing said first outlet semidamper and opening said second outlet semidamper, purge air from said blower is circulated through said first compartment, the first portion of the flow passages, the upstream chamber, the second portion of the flow passages, the second compartment, and out the outlet port via the second outlet semidamper; alternately, on opening said second blower semidamper, closing said first blower semidamper, closing said second outlet semidamper and opening said first outlet semidamper, purge air from the blower is circulated through the second compartment, the second portion of the flow passages, the upstream chamber, the first portion of the flow portion of the flow passages, the first compartment, and out the outlet port via the first outlet semidamper.