Abstract: The boiler includes a tight receptacle having a replenishment manifold which opens into the receptacle at an intermediate level thereof so as to define a first replenishment level. The boiler also includes a normally closed valve controllable to open for venting off the receptacle and thereby defining a second replenishment level thereof which is higher than the first level.

Abstract: A cooler for a shaft furnace comprises a metal plate for protecting the furnace walls from the heat effect arranged in the way of heat flow and a means for cooling said plate. The plate is made in the form of metal pipes filled with a coolant and sealed at the ends thereof. The coolant-filled ends of the pipes are rigidly fixed to the plate, and the coolant-free ends of said pipes are mounted within a cooling chamber with the coolant circulating therethrough. The cooling chamber is arranged exteriorly of the furnace wall. The coolant-free ends of the pipes are disposed slightly above those filled with the coolant. The plate is formed of two layers, namely, a high-heat-conducting layer and a low-heat-conducting one, the former facing the furnace working space and the latter being presented to the furnace wall. The interfacial plane of the layers is parallel to the longitudinal axis of the pipes.The present invention can be advantageously used for the protection of blast-furnace shells.

Abstract: A waste heat recovery system which can be attached to, and made part of, an existing thermal oxidizer-stack system, at minimum cost, without reducing the reliability of the existing oxidizer-stack system. It comprises a conventional heat transfer means, which is connected at its input through a refractory lined first conduit, to an opening through the wall of the first stack of the thermal oxidizer-stack system. The outlet of the heat exchanger is connected through a second conduit to an induced draft means, which can be a conventional blower, the outlet of which is connected to a second stack. The action of the induced draft blower is to cause inflow of hot stack gases through the first conduit and through the heat exchanger and to pass the cooled stack gases out the second stack. A first temperature sensor is placed in the stack between the inlet from the thermal oxidizer and the opening where the gases are drawn into the first conduit. A second thermal sensor is placed in the first conduit.

Abstract: Useful heat is recovered from electric furnaces using two heat recovery systems. Primary heat recovery is effected using liquid water or other cooling liquid and is performed in such a manner that the temperature of the liquid does not exceed its boiling point at atmospheric pressure. Secondary heat recovery is effected by indirect heat exchange between the exhaust gas of the furnace and a gaseous cooling medium and is performed in such a manner that the gaseous medium is heated to a temperature above the boiling point of the cooling liquid. A part or the entirety of the cooling liquid is then heated by the gaseous medium.

Abstract: An exhaust duct for use with a direct evacuation exhaust decontamination system of a blast furnace or steel converter. The exhaust duct includes a main support coolant inlet conduit and a plurality of coolant return conduits arranged in a generally circular pattern to define an exhaust duct having a circular cross section for the evacuation of exhaust gases from a furnace. The inlet conduit and the return cooling conduits are connected to a distribution manifold on one end so that all of the coolant enters the exhaust duct through the main coolant supply conduit and is returned and discharged through the smaller cooling conduits which thereby serve to maintain the exhaust duct at a relatively low temperature to prevent oxidation or destruction of the duct walls by the exhaust gases. The discharged coolant may be directed into the exhaust gases at the end of the exhaust duct for use in a "wet" exhaust cleansing system or collected in a trough or manifold when used with a "dry" exhaust cleansing system.