US1751893A - Regulation of combustion of gases in furnaces - Google Patents

Description

March 25, 1930. A. STEINBART REGULATION OF COMBUSTION OF GASES IN FURNACES Filed Dec. 11, 1925 5 Sheets-Sheet 1 March 25, 1930. A. STEINBART 1,751,893

REGULATION OF COMBUSTION OF GASES IN FURNACES Filed Dec. 11, 1925 3 Sheets-Sheet 2 l Q00 56% j] Z7 Z7 1 q March 25; 1930.

A. STEINBART 1,751,893

' REGULATION OF COMBUSTION OF GASES IN FURNACES Filed Dec. 11, 1925 5 Sheets-Sheet 3 MBA- QML

WITNESSES Patented Mar. 25, 1930 PATENT OFFICE ALFRED STEINBART, F PITTSBURGH, PENNSYLVANIA REGULATION OF COMBUSTION OF GASES IN FURNACES Application filed December 11, 1925. Serial No. 74,736.

In an application filed February 7, 1925,

Serial Number 7 ,636, is described a method of b and apparatus for regulation of combustion of gases in furnaces, such method consisting of supplying air for a preliminary combustion of coal or coke in a gas producer, effecting the combustion of such gas and regulating the supply of air for one of such combustion stages by and in accordance with the air supplied for the other combustion stage.

The apparatus specifically described and claimed in said application for the practice of the method embodied suitable means, preferably fans or blowers, for supplying air to the producer and furnace and the regulation of the air by varying the speed of the fans. In the construction shown and described herein fans .are employed as before stated for supplying air for the respective stages, one fan being operated by a motor, the speed of which can be varied manually or otherwise, while the other fan is operated by its motor at a predetermined and constant speed to maintain a supply of air greater than is necessary in one case to effect combustion of the gas being furnished, and greater in the other case than is necessary for effecting the generation of the quantity of gas desired, the flow of air to the furnace or producer, as the case may be, being regulated by a valve operative by and in accordance with the air supplied to the producer or furnace. The invention is hereinafter more fully described and claimed.

In the accompanying drawings forming part of this specification, Fig. 1 is a plan View illustrating diagrammatically a form or construction of apparatus adapted for the practice of the invention described and claimed herein; Figs. 2, 3 and 4 are views similar to Fig. 1 illustrating modificatons of apparatus for the practice of the invention; and Fig. 5 is a vertical sectional view on a plane indicated by the line VV, Fig. 1, and illustrates the usual form of apparatus employed in supplying steam and air to a producer.

For convenience of description, the air supplied for the preliminary or partial combustion of coal for the formation of gas will be termed primary air and that supplied for combustion of the maximum the combustion of the gas so produced will e termed secondary air.

In the practice of the inventionone or more producers, which may be of any suitable construction, are provided with outlet pipes 2 connected through a gas header 3 to a gas inlet 4 adapted to control the flow of gas to a furnace (not shown). Air is supplied to the producer and to the furnace by fans or blowers 5, 5 through mains 6, 6 the main 6 having branches 7 extending to the several producers. It is preferred that these branches be provided with valves Sin order that a producer may be cut out when cleaning or repair is necessary without interfering with the operation of other producers.

The fans or blowers 5, 5, which may be of any suitable construction, are operatively connected to motors 9, 9, of any suitable construction but preferably of the steam turbine type. As will hereinafter more fully appear, the improvement claimed herein contemplates the regulation of the supply of secondary air for the combustion of the gas by and in accordance with the rate of supply of the primary air for the generation of the gas, or the regulation of the supply of air for the preliminary or partial combustion of the coal by and in accordance with the rate of supply of the secondary air for the combustion of the gas.

Apparatus suitable for regulating the supply of secondary air or air for the combustion of gas generated in the producers by and in accordance with the rate of supply of air to the producer, or primary air, is shown in Fig. l. The fan 5 supplying air to the producer is driven by the motor 9 (shown as a steam turbine) and the speed of the motor and fan is regulable by a valve a to vary the rate of production of gas. The fan 5 supplying secondary air or air for the combustion of the gas, is driven by a motor 9 which is operated at a constant speed so that the fan 5* will at all times supply sufiicient air for the quantity of gas flowing from the producer.

As described in the application heretofore referred to, air is supplied to the respective fans 5, 5, through conduits 11, 11, the inlet orifices of said conduits having areas so related to the areas of the discharge or outlet ports of the fans that the pressure in the supply conduits will be less than atmospheric pressure. Pipes 12, 12 extend from the supply conduits and project up into bells 13, 13*,

submerged to suitable depths in liquid contained in a tank 14. The closed upper ends of the bells are subjected to atmospheric pressure, and hence the positions of the bells w1ll vary as the static pressures in the respective supply conduits is varied bythe flow of air to the producers and furnace.

As it is the purpose in the embodiment'of the invention shown in Figs. 1 and 2, that only the static pressure of the air flowing to the producers and furnace should be employed for regulating purposes, provlsion is made to prevent the dynamic pressure of the air flowing to the producers and furnace from affectingthe pressure of air transmitted by the pipes 12, 12 to the bells. To this end the supply conduits 11, 11*, are provided with enlargements or boxes 15, 15 which are so constructed and the points of connection of the conduits and the pipes 12, 12 thereto and the positions of the inlet orifices 16, '16 are so arranged that the rate of flow of air through the stabilizing boxes will .not have any material effect on the pressure in the bells. In order that there may be a substantial or efiective difference between the pressures within and without the boxes, and consequently within and without the bells, the pressure without the boxes and bells being atmospheric pressure, it is preferred that the.

areas of the inlet ports or orifices 16, 16, should be about one-half the areas of the inlet ports of the fans 5, 5.

The bells 13, 13 are suspended from opposite ends of a lever 17 adapted to control a motor indicated at 18. In the construction shown in Fig. 1 this motor is connected by a cord or other suitable means to an operating member as the lever 19 of the valve 20 adapted to control the flow of secondary air through the conduit 6 to the furnace. In the operation of the described apparatus the speed of the fan 5 will be regulated by the manipulation of the valve a in the steam supply pipe of the turbine 9 until the required quantity of air is supplied to the producers. By the operation of the fan 5 there will be a drop in the static pressure in the box 15 and bell 13 to a pressure below atmospheric pressure and the bell will move down thereby causing such a movement of the motor 18 as to open the valve 20 in the conduit 6 permitting the air to be drawn through the orifice'16 and forced through the conduit to the furnace by the constantly operating fan 5. The rate of flow of air to. the furnace following the shifting of the valve 20 will increase until the drop of pressure in the stabilizing box 15 and bell 13 for example is shown at 20 in movement of the bells 13 and 13 will be checked and the valve 20 will be held in its adjusted position.

In the construction shown in Fig. 1 the rate of supply of primary air to the producers may be changed by shifting the valve A in the connection between the producers and the furnace. The shifting of this valve A would change the pressure in the producers, thereby retarding orpermitting an increase of flow of air to the producer. It is characteristic of the improvement described herein that by the flow of air to the producer the flow of secondary air to the furnace is controlled and vice 'versa. As above described, the flow of air through the conduit 6 to the producer can be controlled by the valve A controlling the flow of gas to the furnace. Such control of the primary air can also be effected by a valve in the conduit 6 ahead of its point of connection with the producer. Such a valve Fig. 2.

As hereinbefore stated, the present invention contemplates also the regulation of the primary air or air supplied to the producers for the generation of gas by and in accordance with the secondary air or air supplied to the furnace for the combustion of gas. Apparatus suitable for such mode of operation is shown in Fig. 2 and is similar to that shown in Fig. 1 and hereinbefore described, except that the motor 9 employed for operating the fan 5 is so constructed that its speed and consequently that of the fan 5 can be varied at will by the manipulation of the valve a when a motor of the steam turbine type is employed. On the other hand, the motor 9 is operated at a constant speed so that the fan 5 will at all times supply a quantity of air to the conduit 6 connected to the, producers greater than is required for the generation of gas at any given time and the flow to the producers is regulated by a valve 20 adapted to beshifted by the motor 18 which is connected to valve lever 19 by a cord or other suitable means. By the operation of the fan or blower 5 the pressure in the box 15 and bell 13 will drop below atmospheric pressure and consequently the bell 13 will move down starting the motor 18 which in turn will shift the valve 20 in the air main 6 permitting air to be forced through the main to the producers by the fan 5. By the operation of this fan the pressure in the box 15 and bell 13 will drop below atmospheric pressure until the pressures in the bells 13 and 13 are equal, whereupon the movement of the bells will be checked thereby checking the operation of the motor 18 which will remain stationary holding the valve 20 in its adjusted position until there is a change of pressure in the box 15 and bell 13. I

In Fig. 3 is shown a construction wherein provision is made for effecting the regulation of air supply by and in accordance with the pressure drop in the primary air on the delivery side of the fan 5. As shown inFig. 3 bells each having two compartments, 22, 22 and 23, 23, are submergedto a considerable depth ina'tank 24 and from the main 6 for the primary air pipes 26-26 extend to the tank and project up one into the chamber 22 of one bell and the other into the chamber 22 of the other bell. The pipes 26, 26 are so connected to the main 6, i. e., on opposite sides of an orifice 28 that the pressure of the air bebind the orifice 28 would be exerted on the compartment 22 of one bell and pressure of the air in advance of the orifice 28 would be exerted on the compartment 22 of the other bell, and the pipes 27, 27 are so connected to the air main 6 leading to the furnace, i. e. on opposite sides of an orifice 28 that the pressure of the air after the orifice 28 will be exerted in the compartment 23 and the pressure before the orifice 28" will be exerted in the compartment 23*. These bells are suspended from a lever 17 adapted to control the operation of a motor 18 connected to a valve 20 controlling the flow of air through the main 6 to the furnace.

As shown in 4, air may be supplied to the producer by means of aspirators 21 of the usual construction (see Fig. 5) arranged in the branche 7 connecting the air main 6 with the produc rs. In such cases the stabilizing box 15 is arranged at the inlet end of the air main 6, and a pipe 12' extends from such. box 15 to a bell in the regulating mechanism. In order to ensure a substantial drop of pressure I in the box 15 when the aspirators are operated, the inlet orifices 16 of the box is made substantially smaller than the outlet from the box to the main 6.

I claim herein as my invention:

1. In combination a furnace, a producer for supplying gas to the furnace, conduits for conducting air to the furnaceand producer respectively, a variably operable means for forcing air through one of said conduits, means adapted to supply to the other conduit a quantity of air greater than is necessary to effect combustion of gas supplied at any given time, a valve in the latter of said conduits, and means operative by and in accordance with changes of pressure in the variably supplied air for shifting said valve.

.2. In combination a furnace, a producer connected to the furnace, variably operable means for supplying primary air to the producer, means for effecting a drop of pressure in the primary air at a suitable point 111 the line flow of such air to the producer, means for supplying to said furnace a quantity of air greater than is necessary for the combustion of the gases supplied by the producer, and means operative by and in accordance with the drop of pressure in the primary air for throttling the supply of secondary air flowing to the furnace.

3. In combination a furnace, a producer connected to the furnace, means for supplying primary air to the producer, means for supplying secondary air to the furnace for the combustion of the gas supplied to the furnace by the producer, means for effecting a drop of pressure in the primary air at a suitable point in the line of flow of such air to the producer, and means operative by and in accordance with the drop of pressure in the primary air for throttling the supply of secondary air flowing to the furnace.

4. A plant having in combination a furnace, a producer for supplying gas to the furnace, means for supplying primary and secondary air to the producer and furnace. respectively, means for effecting drops of pressure at suitable points in the line of flow of the primary and secondary air means whereby the pressures at said points are differentially opposed and means operative by such differentials for throttling the flow of secondary air to the furnace.

5. A plant having in combination a furnace, a producer for supplying gas to the furnace, air supply-means for supplying primary air to the producer, air supply-means for supplying secondary air to the furnace, means for effecting drops of pressure at suitable points in the lines of fiow of the primary and secondary air, means whereby the pressures at said points are dilferentially opposed and means operative by such differentials for throttling the flow of air supplied by at least one of said air supply means.

6. A plant having in combination a furnace, a producer for supplying gas to the furnace, means for supplying primary and secondary air to the producer and furnace, respectively, one of said means being variable and the other operating at a constant rate, means for effecting drops of pressure at suitable points in the lines of flow of the primary and secondary air, means whereby the pressures at said points are differentially opposed and means operative by such differentials for throttling the flow of air supplied by the constant operating means.

In testimony whereof, I have hereunto set my hand.

ALFRED STEINBART.

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