US2336538A - Burner control for reversing furnaces - Google Patents

Description

ma 43. c. J. GElfiEL ET AL 2,336,533

BURNER CONTROL FOR HEVERSING FURNACES Filed Sept. 3, 1940 Z1 1%00221075 c2 4005 165/554 and P558 0. /\//EL5E/V,

Patented Dec. 14, 1943 NITED STATES PATENT OFFICE BURNER) CONTROL FOR REVERSIN FURNACES Claude J.

Lorain,

Geisel, Elyria, and Peer D. Nielsen, Ohio, assignors to National Tube Com- 2 Claims.

This invention relates to burner controls for reversing furnaces, and more particularly to those which are used on open hearth furnaces in the manufacture of steel, although not limited thereto.

through a port on one sideof the furnace and the products of combustion are withdrawn there- 5 In open hearth furnace practice, a combustion sustaining mixture of fuel and air is introduced from through a port on the other side thereof; '10

and from time to time the operation is reversed, the port initially serving as the intake port becoming the exhaust port and vice versa.

It is the usual practice to locate the fuel shutoff and reversing valves at a reversing stand positioned at a substantial distance from the burners which they control. When liquid fuel is used, such as 'oil or tar, there is a considerable quantity thereof left in the line between the valve and the burner and this often increases in temperature after the valve has been closed due to the proximity of the feed line to the highly heated furnace and the accessories thereof. Frequently the fuel feed line is enclosed with a steam line in an insulated wrapper to assist in the heating of the oil or tar previous to atomization, and when the flow of fuel ceases due to the furnace reversal, 7 an increase in the fuel temperature is bound to occur. The liquid fuel remaining in the idle fuel feed line expands with increased temperature and is partially lost through the open end of the line at the fuel burner. Fuel issuing from the burner in this manner burns, but for no useful purpose, and causes objectionable smoking in the furnace as no air is provided for its combustion. This condition causes clogging of'the burner due to the formation of the deposit at its open end.

According to the most prevalent practice, the controls for reversing the furnace are located at furnace could only be accomplished by workmen walking to the required locations. Such centralization of the reversing controls at a remote point gives rise to numerous difficulties; and 4 -a central point as otherwise the reversal of the 40 the opening of appear more fully hereinafter and we have,

5 at Hand l2.

therefore, sought to avoid the simultaneous interrupting flow of fuel to one burner and initiation of flow to the other in coordination with the operation of interrupting the steam flow to one burner and initiating the stea flow to the other.

It is among the objects of the present invention to provide a reliable and eflicient reversing control for fuel burners.

Another object is to provide a system of the class described which is so constructed and arranged as to require the elapse of an interval of time between the interruption of flow of fuel to one burner and its initiation to the other, to-

gether with the purging of the burners with steam or other fluid both before and tion thereto of the liquid fuel.

Another object is to provide a system of the class described with the controls located at a remote point and so constructed and arranged as to provide for selective operation of thevalves.

The foregoing and other objects will be apparent after referring to the drawing, in which: 7

Figure 1 is a diagrammatic view of the fuel apparatus of a furnace provided with apparatus embodying the teachings of the present invention;

Figure 2 is a view partly in side elevation and partly in section of one of the fuel valves of the apparatus of the present invention; and

Figure 3 is a diagrammatic view of additional apparatus to be used in conjunction with the apparatus of Figure 1.

Referring more particularly to the drawing, the numeral 2 generally designates an open hearth furnace provided on either side with a liquid fuel burner, as at l and 5. As stated hereinbefore, it is old in the art to position burners in these locations and provide them with liquid fuel through suitable fuel feed supply pipes as designated at 8 and 1, controlled from a remotely disposed control station 9. In order to atomize the fuel fed through the supply lines 8 and l, steam is furnished to the burners 4 and 5 through suitable pipes, respectively designated Within each of the steam pipes at'points adjacent the burners 4 a solenoid operated valve, as at I3 and M, the latter being controlled through suitable electric circuits I6 and I! from the control station 9. It is additionally old in the art to provide within the fuel feed supply pipes 6 and 1, and adjacent to the burners4 and 5, suitable pressure operated valves designated hereinafter at 20 and 2! and connected to and operated by the steam supply pipes II and I2. Prior to the after the applica- II and I2 and and 5, there is present invention, the foregoing combination of elements was so arranged and operated one with respect to the other that the atomizing agent (i. e., steam), is used to open fuel valves immediately in back of the burners.

According to the teachings of the present invention, there is provided at the locations designated hereinbefore at 20 and 2 I, valves operated by the pressure from the steam pipes II and I2. Each of the valves 20 or 2I comprises a valve body 200, see Figure 3, provided with an oil inlet port 20I which communicates with a chamber 202, from which the oil is permitted to flow through a restricted orifice 203 into a smaller chamber 204. From the small chamber 204 the oil issues through a port 205 to be fed to the burners designated hereinbefore at 4 and 5. Through the restricted orifice 203 there extends a valve stem 2I0 which projects through a packing gland 2I I at the top of the valve body 200. Within the chamber 202 the valve stem 2l0 carries a valve generally designated at 2I3. This valve 2I3 carries a valve seat 2I4 which is adapted to seat against a similar valve seat 2l5 which is carried in the restricted orifice 203. In parallelism with the valve stem 20I the valve body 200 is provided with a cylindrical chamber 220 in which there is disposed a piston 22I, the latter being movable upwardly by means of steam admitted through a port 223 in the bottom of the valve body 200. The top of the piston 22I is provided with a valve seat 225 which is adapted to seat against a valve seat 226 in a restricted aperture 221 which communicates with a chamber 229 of smaller diameter than the cylindrical chamber 220. The chamber 229 carries a coil spring 230 which extends through the restricted aper re 221 and seats in a recess 23I in the top of, he piston 22I. Secured to the top of the piston 22I is ashaft 232 which projects through an opening 233 in the top of the valve body 200. Pivotally connected to the top of the shaft 232 is one end of a link 240 which is, on its other end, pivotally connected to the top of the valve stem 2l0. At a position closely adjacent the valve stem 2l0 the link 240 is pivotally connected to a post 242 which is integrally formed on the top of the valve body 200, the mechanical advantage afforded thereby being in the ratio of 2 A; to 1. By providing at the points designated 20 and 2|, a valve body 200 and associated lnstrumentalities, and connecting the respective steam supply pipes I I and I2 to the ports 223, the liquid fuel feed supply pipes 6 and I to the ports 20I, and the fuel burners 4 and 5 to the ports 205, there is provided a system the burner 5 to be idle, the operator reverses the furnace by operating the switch l8 in the electrical line IE to close the solenoid operated valve thereby cutting off the supply of steam coming through the pipe II. When the pressure of the steam remaining in the pipes beyond the valve 53 drops sufficiently, the spring 230 in the valve body 200 operating against the pressure of the steam coming through the port 223 presses the piston 22! downwardly. The downward movement of the piston 22E moves with it the integral shaft 232 and that end of the link 240 which is pivotally connected to the top of the latter. Through the mechanical advantage of 2% to l, the valve stem 210 is raised, thereby moving into contact the valve seat 2M on the valve 2I3 with the valve seat 2I5 carried in the restricted orifice 203. The closing of the valve 2I3 cuts off the flow of oil issuing from the port 205. After the oil valve closes, the burner 4 is automatically purged by the expansion and dissipation of steam remaining in the pipe I I.

In order to set in operation the burner 5, the operator closes the switch I9, which opens the solenoid operated valve l4, thus admitting steam to the burner I5 to thereby purge the burner 5 prior to the application of fuel. As soon as the back pressure of steam in the pipe I2 builds up slightly, it overcomes the force of the spring 230 which, in a manner reverse to that described in conjunction with the discontinuing of burner 4, opens the valve 2I3 and admits oil from the port 20I to the chamber 202, restricted orifice 203, chamber 204 through the oil outlet' port 205 to the burner 5.

From the foregoing, it will be observed that the valves 200, disposed at the locations 20 and 2I in Figure 1, are opened by the application of atomizing steam and are closed by means of springs 230 when the atomizing steam is shut off. The spring 230 are, of course, made to resist the steam pressure desired under the minimum pressure required for atomization.

Referring more particularly to Figure 3, there is provided in each of the steam supply pipes II and I2 a lubricating oil trap 250 for each of the valves 20 and 2|. These oil traps 250 serve the joint purpose of lubricating the pistons 22I and their respective valves and also to prevent steam coming into contact therewith. Preferably both of the pistons 22I are provided with oil grooves to prevent the escape of oil past the pistons 22I before the'valve seats 225 and 220 are closed.

A vent (not shown) is provided in each of the cylindrical chambers 220 to permit the escape of air or seepage and to prevent equalization of pressure above and below the pistons 22I,

By using the atomizing agent (i. e., steam) as the operating media of the valves 200, the proper manipulation of the atomizing agent and liquid fuel, with respect to the proper sequence of ap plication and removal, is absolutely assured.

Referring again to Figure 3, it will be perceived that on its way from the port 205 to the burners 4 or '5, the oil flows to and through an atomizer 25L In addition, in each of the steam supply pipes II and I2 there i provided a steam chamber 252. These steam chambers 252 are disposed between the lubricating oil traps 250 and the atomizers 25L By employing atomizers in advance of the burners and atomizing steam cham= bers 252 which constitute enlargements of the steam supply pipes II and I2 the purging of the burners may be increased.

The lubricating oil traps 250 can be made of any size to effect the desired purging before and after the application to shut off respectively the liquid fuel and also serve as a reservoir for the atomizing agent (i. e., steam).

While we have shown and described one specific embodiment of the present invention, it will be seen that we do not wish to be limited exactly thereto, since various modifications may be made without departing from the scope of the invention, as defined by the following claims.

We claim:

1. A burner control comprising a plurality of fuel burners, a pipe for supplying liquid fuel to each of said fuel burners, a valve in each of said pipes said valves being disposed adjacent the fuel burners they control, a conduit arranged to deliver fluid under pressure for atomizing the fuel supplied to each of said burners, a valveoperating means organized with each of said valves, said means comprising chests severally communicating with said conduits and including valve-shifting members movable between alternate positions upon changing from one to the other of alternate conditions of pressure in said conduits, a remote control station including control means operable for selectively controlling the supply of fluid under pressure to each of said conduits and thereby efiecting the individual operation of said valve-operating means, said burners being pur ed by said atomizing-fluid upon fuel supplied to each of said burners, a valveoperating means organized with each of said valves, said means comprising chests severally communicating with said conduits and including valve-shifting members movable between alternate positions upon changing from one to the other of alternate conditions of pressure in said conduits, a valve in each of said conduits, said last-named valves being disposed adjacent the fuel burners aforesaid, a remote control tation including control means operable for selectively operating said last-named valves to control the supply of fluid under pressure to said conduits and thereby effect the individual operation of said valve-operating means, said burners being purged by said atomizing fluid upon changing the pressure condition in said conduits, and means for delaying the movement of said shifting members upon supplying ato-mizing fluid to said conduit until the said fluid purges said burners, each of said conduits including an enlargement whereby purging of the burners is increased.

CLAUDE J. GEISEL. PEER D. NIELSEN.

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