Recuperator structure

Abstract

A recuperator structure for recovering heat values from a hot gas stream comprising exhaust gases from a combustion burner supplied with combustion air for burning a fuel in which a heat exchanger is used for exchanging heat between the hot exhaust gases and the combustion air for preheating the combustion air and including a variable temperature control for selectively restricting the volumetric flow of either the air or the exhaust gases or both through the heat exchanger in order to control the temperature in the heat exchanger.One of the features of this invention is to provide a recuperator structure for recovering heat values by extracting heat in a heat exchanger from the hot exhaust gases from a combustion burner and using this heat in the exchanger to preheat the combustion air to the burner and including means for controlling the temperature in the heat exchanger by controlling the volumetric flow of either the combustion air or the exhaust gases or both through the heat exchanger.

Description

Claims

1. Recuperator structure for recovering heat values from a hot gas stream comprising exhaust gases from a combustion burner, comprising: an exhaust gas conduit from said burner; a combustion air conduit to said burner; a heat exchanger having exhaust gas passages in heat transfer relationship with combustion air passages for transferring heat from the exhaust gas to said combustion air; temperature control means for selectively restricting the volumetric flow of at least one of said combustion air and said exhaust gases through the heat exchanger for controlling the temperature in said heat exchanger; means for arranging said heat exchanger exhaust gas passages and combustion air passages in a plurality of modules of the heat exchanger with all modules being positioned in separate passages each controlled by a separate flow control damper; and force yieldable heat insulation means separating each said module from adjacent modules for compensating for thermal dimensional changes and for sealing the gases in the adjacent modules from each other.

2. Recuperator structure for recovering heat values from a hot gas stream comprising exhaust gases from a combustion burner, comprising: and exhaust gas conduit from said burner; a combustion air conduit to said burner; a heat exchanger having exhaust gas passages in heat transfer relationship with combustion air passages for transferring heat from the exhaust gas to said combustion air; temperature control means for restricting said volumetric flow of both said combustion air and exhaust gases in substantially equal volumetric ratios, said heat exchanger comprising a plurality of parallel passages for said exhaust gases and a plurality of parallel passages for said combustion air and said temperature control means comprising a plurality of shutters; means for moving said shutters conjointly for said blocking of desired passages, said combustion burner being part of a heat treating furnace, said temperature control means comprising a temperature sensor exposed to the heat in said furnace; a plurality of temperature control shutters operated by said sensor, said heat exchanger exhaust gas passages and combustion air passages being arranged in a plurality of modules of the heat exchanger with all modules being positioned in separate said passages; a separate flow control damper for each said separate passage; and force yieldable heat insulation means separating each said module from adjacent modules for compensating for thermal dimensional changes and for sealingly separating the gases in the adjacent modules from each other.

3. Recuperator structure for recovering heat values from a hot gas stream comprising exhaust gases from a combustion burner, comprising: an exhaust gas conduit from said burner; a combustion air conduit to said burner; a heat exchanger having exhaust gas passages in heat transfer relationship with combustion air passages for transferring heat from the exhaust gas to said combustion air; and temperature control means for selectively restricting the volumetric flow of both said combustion air and said exhaust gases in substantially equal ratios through the heat exchanger for controlling the temperature in said heat exchanger, said heat exchanger comprising a plurality of parallel passages for said exhaust gases and a plurality of parallel passages for said combustion air and said temperature control means comprising means for blocking desired passages to restrict gas flow therethrough, said temperature control means comprises a plurality of shutters and means for moving said shutters conjointly for said blocking of desired passages, said combustion burner is part of a heat treating furnace, said temperature control means comprises a temperature sensor exposed to the heat in said furnace and there are provided a plurality of temperature control shutters operated by said sensor.