GB270184A - Improvements in and relating to the control and reversal of regenerative furnaces - Google Patents

Abstract

270,184. White, A. E., (Morgan Construction Co.). Dec. 7, 1926. Regenerators; valves, reversing.-In a regenerative furnace from each end of which leads an outwardly opening duct air is supplied to each duct in an outwardly-directed jet, either one of the jets delivering air at high velocity to discharge the waste gases by entrainment while the other jet delivers air at such low velocity that the air flows into the furnace under the influence of the draught instead of passing out through the open end of the duct. Dampers may be arranged in the ducts and operated jointly with the means for supplying air to the ducts. The air regenerator passages 2, 2<1> are connected to upwardly opening ducts 3, 3<1> in the form of Venturi tubes within which are arranged upwardly directed nozzles 4, 4' supplied with air by fans 5, 5<1>. Dampers 7, 7<1> arranged in the throat portions of the ducts are closed by solenoids 10, 10<1> through plungers 9, 9<1> and arms 8, 8<1> and returned to the open position, in the absence of current through the solenoids, by counterweights 11, 11<1>. For joint control of the position of the valves and the quantity of air supplied by the respective nozzles hand levers 13, 13<1> co-operate with resistance elements 12, 12<1>, in the circuits of the motors for the fans 5, 5<1> and contacts 14, 14<1> in the circuits of the solenoids 10, 10'. As shown, the greater part of the resistance 12<1> is in circuit so that the fan 5<1> operates at a low speed, while the solenoid 10<1> is energized through the contact 14<1> so that the valve 7<1> is closed and the air from the nozzle 4<1> passes into a furnace by the port 15' the burner 1<1> being in operative position. The resistance 12 is cut out so that the fan 5 works at a high speed, and the solenoid 10 being de-energized the valve 7 is open; the jet from the nozzle 4 thus exhausts the waste gases through the port 15. The contact 14<1> is of such length as to permit limited manipulation of the hand lever 13<1> without breaking the circuit of the solenoid 10<1> so that the quantity of air supplied to the nozzle 4<1> at low velocity may be varied. Variation of the entraining action is obtained by adjusting the hand lever 13 in its high speed position remote from the contact 14. To reverse the furnace the hand levers 13, 13<1> are thrown to the left, the burner 1 brought to the operative position and the burner 1<1> made inoperative. Fig. 3 shows a modification in which the ducts 3, 3<1> are arranged in juxtaposition and the nozzles 4, 4<1> supplied with air from a common blower through a duct 18, a damper 19 being arranged to distribute the air between the two nozzles. An arm 20 secured to the damper 19 is connected by a link 21 and adjustable connection 22 with an arm 23 secured to the spindle of one of the valves 7, 7<1>. Arms 24 secured to the dampers, 7, 7' are connected by a link 25 and connecting rod 27 to a crank 26. As shown the greater part of the air from the duct 18 flows to the nozzle 4 and the valve 7 being open the waste gases are exhausted through the duct 3. A small quantity of air passes to the duct 3<1> through the nozzle 4<1 >and thence to the furnace. Reversal is effected by turning the crank 26 through 180‹ to close the valve 7, open the valve 7' and rock the valve 19 to the left so that it restricts the flow of air to the nozzle 4 and allows free flow to the nozzle 4<1>. After the furnace has become sufficiently hot reversal can be effected without the manipulation of the dampers 7, 7<1> the shape of the ducts ensuring that the air which is under low pressure passes into the furnace under the action of the draught.