US1936621A - Open hearth furnace - Google Patents

Description

Nov. 28, 41933. G, w FlNNEy 1,936,621

OPEN HEARTH FURNACE Filed Sept. 14, 1931 2 Sheets-Sheet l G. W. FINNEY OPEN HEARTH FURNACE Nov. 28, 1933.

Filed Sept. 14. 1931 2 Sheets-Sheet 2 62 0 e 71 722139 g z yz m Patented Nov. 28, 1933 UNITED STATES Learn PATENT orrice Application September 14, 1931 Serial No. 562,697

- 10 Claims.

This invention relates to improvements in open hearth furnaces and it consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The invention is more particularly concerned with the regenerators of the furnace and the associated rlues connecting them with the stack and blower system. In the operation of the fur: nace the products of combustion from the hearth pass through the regenerators at one end of the furnace and the checker work absorbs heat therefrom. After a suitable period, the passage is reversed with the incoming cooler air and gas (when the furnace is a gas fired one) entering through that regenerator just mentioned, when the products of combustion from the hearth pass out the regenerator at the other end of the furnace to heat the checker work for the next reversing pass through the furnace. In this manner, the regenerators are maintained at a high temperature to preheat the air (and gas) before the same reaches the hearth for combustion.

Each regenerator has two compartments. or chambers and one is about twice the cross sectional area of the other and includes checker work in proportion. When using liquid fuels, both compartments are employed in preheating air and when gas is used as a fuel the smaller compartment is employed for preheating gas and the larger one is used for preheating air. 7

Tests disclose undesirable conditions exist in the regenerators in that a channelling of the in coming air takes place and dead or inert spaces develop wherein the temperature remains the same regardless of whether the hot gases are passing out of the same or the cooler air is entering the same. Again such tests disclose that the temperatures in one compartment often differs and in fact, in some instances, the temperatures in the large compartment of the regenerator at one end of the furnace is the higher and in some instances the temperature in the smaller compartment of the regenerator at the other end of the furnace is the higher.

It is apparent that such uneven temperatures resulted in a loss of efficiency and in an increase of the amount of fuel (either liquid or gas) necessary to support combustion with a resulting increase in the cost in making steel.

Attempts have been made to correct these conditions, such as by changing the brick Work inthe neck arches so that the openings thereof were in proportion to the size of the associated chamber. Again, it has been attempted to control the amount of cooler air entering each chamber in proportion to its size. Baffies have been resorted to in the chambers of the regenerator to make them a three-pass chamber. tioned had some value so far as air preheating was concerned but a greater variance in temperatures was disclosed in the same regenerator.

The primary object of the invention is to pro.- vide a simple and eflicient means whereby the above mentioned objections are readily overcome and which means is disposed outside the furnace easy for access in the required adjustments which are maintained for long periods of time.

A further object of the invention is to provide an improved means associated with the bulkhead ends of the chambers of the regenerators whereby the outgoing products of combustion may be controlled, so that the same is more evenly distributed in the chambers of the regenerators, channelling and dead air pockets or spaces are eliminated'and volume and direction is regulated, thereby reducing fuel consumption with an improved economy and efliciency in operation.

- The above mentioned objects of the invention, as Well as others, together with the many advantages thereof, will more fully appear as I proceed with my specification.

In the drawings:-

Fig. 1 is a View partly in top plan elevation and partly in horizontal sectionof an open hearth furnace embodying my invention.

Fig. 2 is a view on an enlarged scale, partly in end elevation and partly in section of the bulkhead end of one of the regenerators and illustrates the damper members associated therewith.

. Fig. 3 is a horizontal detail sectional View on a further enlarged scale as taken on the line 33 of Fig. 2. I

In general, my invention contemplates the provision of sets of dampers preferably associated with and outside the bulkhead ends of the regenerators, which dampers may be set to control the volume and direction of the outgoing products of combustion in a manner causing an even temperature throughout each chamber of each regenerator and a substantially equal .temperature in both chambers of each regenerator. Thus by setting the dampers of each regenerator in accordance with the conditions of the outgoing products of combustion to provide a uniform heat curve therefor, it is possible to retain such a curve for both the outgoing products of combustion in one instance and the incoming air in the other instance.

Ref rring now in detail to that embodiment of the invention, illustrated in the accompanying drawings:1 indicates as a whole the body of an open hearth furnace formed to provide a hearth 2, and 3, and 4 indicate respectively the associated regenerators extending laterally from each end of the furnace, both the body and the regenerators being buck stayed and braced in accordance with the practice employed in furnaces of this kind. For the sake of simplicity and clearness, such buck stays and bracing has been shown only in a general way in the drawings herein.

In the furnace body, at each end of the hearth are the uptakes 5 and 6 respectively, one disposed upon each side of the median plane of the furnace body. When gas is the fuel employed one of said uptakes is used as the gas uptake and the other one is used as the air uptake. When liquid fuel is employed, the same is fed into the furnace by nozzles at the opposite ends of the body in the manner well-known, and then both uptakes are used for air alone.

Each regenerator comprises the upright side and intermediate walls, '7 and 8 respectively, roof 9 and inner and outer bulkhead walls 10 and 11 respectively. In each chamber is provided the usual checker Work 12 and below the same are provided the associated ducts. The respective uptakes at each end of the furnace body are connected to the inner bulkhead end of the regenerator chambers by necks 13 and 14 respectively and the outer bulkhead wall terminates at its bottom insubstantially the plane of the checker work so as to expose the associated end of said ducts.

The ducts are connected by branches 15 and 16 respectively with a main header flue 17 leading to a stack 18. The main header is also operatively connected with an air duct 19 and suitable valves are provided in the various ducts to control the outgoing products of combustion in accordance with the usual furnace practice,

At a location adjacent the outer bulkhead end of each regenerator and preferably outside the same, I provide a suitable damper mechanism by which the volume as well as the directional distribution of both the outgoing products of combustion and the incoming air (and gas if the same is used for fuel) are controlled and which mechanism may be adjusted to meet the desired conditions.

In connection with such mechanism, I provide extensions 20 on the upright outer bulkhead walls of the regenerators which project outwardly beyond the plane of the same and these extensions terminate at the top in substantially the plane of the bottom of the checker work. In said wall extension are formed upright grooves 21.

In the plane of said grooves and associated with each chamber is a set of dampers in the form of a plurality of vertically movable plates 22- and 23 respectively, the outer ones in each set, having a guided engagement in the grooves of' the wall extensions and certain other ones of the same set having means along one edge to provide grooves 24 to receive the margins of the adjacent plates.

The plates of each set of dampers as shown herein are of a greater vertical height than is the height of the ducts below the checker work and may be raised and lowered in any suitable manner. As shown hereineach plate has operativelyconnected to its top endthe bottom.

end of a rod 25 and the top end of said rod is threaded and extends up through a suitable supporting member 26 common to all of the damper plates of both sets. Said support may be provided by a horizontally disposed channel beam engaged by outstanding brackets 27 on the bulkhead wall of the generator. The rods mentioned extend up through openings in the supporting member and are each provided with a nut 28 engaged upon said supporting member. Thus when the nuts are turned in one direction the damper plates are raised and when the nuts are turned in the other direction they are lowered.

By means of the structure described, the various damper plates may be adjusted to those positions giving the best operation for the intended purpose.

The damper plates may be dry plates wherein no water cooling is provided because being outside the furnace, they will not be affected by the temperatures of the outgoing products of combustion. However, these damper plates may be Wet or water cooled ones, should it be so desired.

In the adjusting of the dampers, temperature readings are taken at various points throughout the regenerators and when such readings indicate dead pockets or channelling, then the desired damper in each set is manipulated by either raising or lowering the same.

This will cause the outgoing products of combustion to take a definite path thus regulating the volume, direction and distribution thereof, so that the temperature is substantially equalized throughout the regenerator. In making these adjustments, the best results are ob tained in working on the outgoing products of combustion because when that regenerator is employed as an intake the temperatures of the chambers thereof remain uniform although this temperature gradually becomes reduced.

With such a mechanism, with the temperature being even throughout the chambers, said temperatures may be lowered to that one providing the most efficient action and as such even temperatures requires less fuel it is apparent that a saving in fuel is obtained. With the elimina tion of the dead spaces and channelling before mentioned, the burning out of the checker Work in the associated areas is also eliminated.

While in describing the invention, I have referred in detail to the form, arrangement and construction of the parts thereof, the same is to be considered as illustrative only, so that I do not wish to be limited thereto except as may be specifically pointed out in the appended claims.

I claim as my invention:-

1. In combination with a furnace, means providing regenerators with chambers therein connected at one end to the furnace, flues connected to the other end of the regenerators, and means arranged closely adjacent one end of said regenerator and operable for controlling the volume and directional distribution of gases throughout the said chambers in the passage of said gases through the regenerators to and from the flues.

2. In combination with a furnace, means providing regenerators with chambers therein connected at one end to the furnace, flues connected the volume and directional distribution of gases G throughout said chambers in the passages of said gases through the regenerators to and from the flues.

3. In combination with a furnace, means providing regenerators with chambers therein connected at one end to the furnace and having a bulkhead wall at the other end, flues connected to said bulkhead wall and means disposed between said wall and flues and supported from said wall and movable in the plane thereof for controlling the volume and directional distribution of gases throughout said chambers in the passage of the same through the regenerators to and from the flues.

4. In combination with a furnace, means providing regenerators with chambers therein connected at one end to the furnace and having a bulk head at the other end, flues connected to said bulkhead and damper members supported from and movable in the plane of the bulkhead for controlling the volume and directional distribution of the gases throughout said chambers in the passage of the same through the regenerators to and from the flues.

5. In combination with a furnace, means providing regenerators with chambers therein connected at one end to the furnace and including a bulkhead at the other end, flues connected to said bulkhead, and a plurality of damper members associated with each chamber and supported from said bulkhead and movable in the plane of the same, said damper members being individually adjustable to control the volume and directional distribution of gases throughout said chamber in the passage of the same through the regenerators to and from the flues.

6. In combination with a furnace, means providing regenerators with chambers therein connected at one end to the furnace and including a bulkhead at the other end, flues connected to the other end of the said bulkhead, a plurality of individually adjustable damper members associated with each chamber and supported from said bulkhead and movable in the plane of the same for controlling the volume and directional distribution of gases throughout said chambers in the passage of the same through the regenerators to the flues and vice versa and means on said bulkhead and on said damper member respectively for guiding said members in their adjustments.

'7. In combination with an open hearth furnace, means providing regenerators with chambers therein connected at one end to the furnace, flues connected to the other end of said regenerators and means arranged closely adjacent and supported for movement in the plane of the last mentioned end and operable to control the volume and directional distribution of said gases throughout said chambers so as to eliminate dead spaces and channeling action of said gases in their passages through the regenerators to and from the flues.

8. In combination with an open hearth furnace, means providing regenerators with chambers therein connected to the other end of said regenerators and means supported by but closely adjacent the last mentioned end and movable in a plane parallel therewith for controlling the volume and directional distribution of said gases throughout said chambers so as to eliminate dead spaces and channeling action of said gases in their passage through the regenerators to and from the flues.

9. The method of operating a furnace of the kind described which includes a regenerator chamber and a flue connected thereto at the bulk head end thereof and which method consists in taking temperature readings in various parts of the regenerator chamber to locate unequalized temperature conditions therein and then changing the shape and cross sectional area of the bulk head end of the chamber to modify the volume and direction of the gases and thereby substantially equalizing the temperature throughout said chamber.

10. The method of operating a furnace of the kind described which includes a regenerator chamber and a flue connected thereto at the bulk head end thereof and which method consists in taking temperature readings in various parts of the regenerator chamber to locate unequalized temperature conditions therein and then changing the shape and cross sectional area of the outlet of said chamber to modify the volume and di rection of the gases and reduce draft action in certain other portions of said chamber to modify the volume and direction of the gases to substantially equalize the temperature throughout said chamber.

GEORGE W. FINNEY.

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