US2137856A - Furnace - Google Patents

Description

NOV. `22, Q. D, RICE FURNACE Filed Dec. 17, 1937 ll-NIVENTOR Orl/12H61?. ,Rice

Patented Nov. 22, 1938 ,y s p UNITED N STATES PATENT OFFICE FURNACE n Orville D. Rice, Pittsburgh, Pa., assigner to Rust Furnace Company,v1ittsburgh, Pa., a corporation of Delaware l Application December 17, 1937,seria1 No. 180,336

zcxaims. (o1. ess- 15) This invention relates to a furnace, in particu- Air for combustion is supplied to the regenerlar to a furnace of the so-called regenerative ator opposite that which is connected to the flue, type in which fuel is supplied from one side and by a blower 25 through piping 26 communicating combustion` products taken off at the other side with the flues I9 and 20. A regulating valve 2l during one period, and the direction of firing reand reversing valves 28 and 29 control the supply versed during a succeeding period. The invenof air to the regenerators. .A diversion flue 30 tion will furthermore be described herein with extends from the flues I9 and 20 adjacent the reference to a soaking pit furnace although it point where they join to an interconnecting flue may be applied as well to furnaces of other types. 3|, extending between flues I9 and 20. A blower 10 It has long been realized that in the operation 32 is disposed in flue 30 and is effective to draw 10- pf regenerative soaking pit furnaces, fuel of low Waste gases from the ilues I9 and 20 and divert caloriiic value has an advantage in that it is less them to the interconnecting flue 3|. Reversing `likely to cause washing or melting of the ingot valves 33 and 34 are located in the flue 3|, making surfaces than is fuel of higher thermal content it possible to direct the diverted waste gases tobecause such washing or melting introduces the Ward the regenerator on the side of the furnace 15 necessity of chipping surfaces `of the ingots to at which fuel is being delivered.

remove these defects. On this account `blast With the various control and reversing valves furnace gas has been widely used for firing soakin the positions indicated, fuel is supplied to the ing pit furnaces. ports I4 between the regenerator |3and the pit I have invented a furnace and method of oper- I I. At the same time, air is delivered by blower 20 ating the same which secures the advantage of through valves 21 and 29 and the flue 20 to fuel having a low heat content in furnaces fired the regenerator I3. The air is heated by passing with fuel having a relatively high heat content. through the regenerator and, as it mixes with the In accordance with my invention, I divert a fuel supply through the ports I4, combustion 25 portion` of the combustion gases flowing from occurs in the pit II. Combustion gases flow 25 the furnace toward the stack and return them through the regenerator I2, the flues I9 and 2| tothe side of the furnace on which fuel is being to the stack 22, since the valve 23 is open and supplied. After passing through the regenerator the valve 24 closed.

on the side with the air supplied for combustion, As indicated by the arrows 35, `a. portion of the the air and combustion gases are mixed `with the waste gases flowing toward the stack 22 is diverted 30 fuel and combustion occurs in Ithe soaking pit through the flue 30 by the blower 32 and delivered proper. through the flue 3| to the flue 20, since the valve A present preferred embodiment and practice 33 is closed and the valve 34 is open. In this of the invention is illustrated in the accompanymanner, the diverted portion of the waste gases 35 ing drawing and a complete understanding thereis mixed with the air entering the regenerator I3 35 of may be gained from the following detailed and ultimately with the fuel delivered through description. `In the drawing: the ports I4. Both the air supplied by the blower` The single figure is a diagrammatic view illus- 25 and the diverted portion of the waste gas suptrating a regenerative soaking pit furnace and plied by the blower 32 are preheated to a temperathe connections therefrom to fuel and air supply ture of approximately 2000 F. The fuel is ad- 40 means and to a stack for discharging waste gases. mitted in finely divided streams, so that it mixes Referring in detail to the drawing, a regenerintimately with the air and waste gases before ative soaking pit furnace I0 comprises a pit entering the pit. By this method I obtain high proper, indicated at II, and regenerators I2 and thermal efficiency and still preserve the desired 4,5 I3. Fuel supply ports I4 are disposed between temperature of the gases in the pit. The inven- 45 the regenerators and .the pit proper and are tion also makes it possible to maintain a large connected by suitable piping indicated generally volume of gas flow through the furnace, which at I5, to a convenient source of fuel. The fuel is desirable. supply to the ports I4 is controlled by a regulating When the direction of firing the furnace is to valve I6 andreversing' valves I1 and I8. be reversed, the valve IB is closed and the valve 50 `'lues I9 and 20 extend from the regenerators Il is opened. The relative positions of valves 23 I2 and I3`to a stack flue 2| communicating with and 24, 28 and 29, 33 and 34 are reversed. The the stack indicated at 22. Reversing valves 23 same result as that already described ensues, exand 24 in the flues I9 and 20 permit either regencept in the reverse direction. i erator to be connected to the stack 22. The amount of waste gases diverted and recir- 55 culated through the furnace is preferably varied in accordance with the condition of the ingots being heated. This may be accomplished by suitable control valves or by varying the speed of the blower 32. When heating cold ingots, little or no waste gas need be recirculated since the danger of melting or washing is slight. As the temperature of the steel rises, the quantity of waste gases diverted from the stack for recirculation is increased. 'I'his method of operation provides relatively quick heating in the earlier stages when the rate of temperatures is rapid, dropping olf as the temperature increases because of the recirculation o! increased quantities of waste llses.

Although I have illustrated and described but a preferred embodiment and'practice of the in` vention, it will be understood that changes in the construction and procedure disclosed may be made without departing from the spirit of the invention or scope of the appended claims.

I claim:

1. In a furnace, a combustion chamber, a regenerator on each side of said chamber, means for supplying fuel selectively to either side of said chamber, iiues having one end connected together and the other extending to said regenerators and adapted to serve alternately as `airsupply and waste-gas passages, means for selectively supplying air to said iiues and means eiiective to divert waste gases from the connected ends-of said flues to points intermediate the ends.

2. In a furnace, a combustion chamber, regen- =erators on each side thereof, fiues leading from said regenerators to a common discharge point, means for supplying fuel and air selectively to either side of said chamber, reversing valves in said flues between said point and said regenerators, and by-passing ues extending from said point to points in said mst-mentioned flues intermediate said valves and said regenerators.

ORVILLE D. RICE.

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