US1929230A

US1929230A - Art of regulating combustion in

Info

Publication number: US1929230A
Authority: US
Publication date: 1933-10-03
Anticipated expiration: 1950-10-03

Description

Och 3, 1933.

G. WNSCH ART OF REGULATING COMBUSTION IN FURNACES 0R THE LIKE Filed Feb. 16. 1952 atented Get. 3, 1933' UNTED STATES `ART 0F REGULATING COMBUSTION IN FURNACES 0R THE LIKE Guido Wnsch, Berlin-Steglitz, Germany, as-

signor to ASkana-Werke Aktiengesellschaft, Berlin-Friedenau, Germany, a corporation of Germany Application February 16, 1932. Serial No. 593,309

14 Claims.

This invention relates to the regulation of combustion in furnaces or the like.

The invention and its aims and objects will be clearly understood from the following description, taken in connection with the accompanying drawing of one embodiment of the invention herein shown and described for illustrative purposes, the true scope of the invention being more particularly pointed out in the appended claims.

In the drawing:

Fig. 1 is a diagrammatical top plan view, partly in section, of apparatus comprising an illustrative embodiment of the invention;

Fig. 2 is a diagrammatical side view, partly in section of one of the fuel feed worms, its hopper, connecting pipe and driving connection, and of illustrative means for rendering said pipe and driving connection operative and inoperative;

Fig. 3 is a detail of the driving connection for one of the worm conveyors and of illustrative means for rendering it operative and inoperative.

Referring to Figs. 1 and 2, said figures diagrammatically show a furnace 2 comprising a boiler 4 and superheater 6. Combustion air may be supplied to said furnace through a grate or in any other suitable manner not shown.

The invention is applicable to furnaces using any suitable fuel, gaseous, liquid or solid. In the illustrative embodiment of the invention herein represented the invention is shown as applied to a furnace using powdered fuel, namely coal dust which may be supplied or fed to the furnace by any suitable means, as by a plurality of fuel feed Worms or conveyors 8 contained in suitable housings 10 and to which fuel may be supplied through hoppers 12, only two of which are shown in Fig. 1 the third being omitted for clearness.

Any number of feed Worms may be used, three being herein provided, each of which feeds the fuel to the furnace through a burner 14 to which the air necessary to form the coal dust mixture is supplied through a pipe 16.

To drive feed worms 8 their shafts 20 carry bevel gears 18, each adapted to mesh with a separate bevelled gear 22 fast upon a shaft 24. Also on said shaft 24 is a bevelled gear 26 which meshes with a bevelled gear 28 fast upon a shaft 30 driven from any suitable source of power, a motor 22 for example to which electrical energy is supplied from any suitable source (not shown) over

conductors

34, 36 and 38.

Means may be provided to vary the amount of fuel fed to the furnace. In the illustrative embodiment of the invention shown this may be effected either by varying the drive of said feed Worms by varying the number of revolutions of said motor 32 or by rendering inoperative one or more of said feed worms 8. To vary the number of revolutions of said motor a relatively adjustable contact 42 and resistance 40 may be included in the motor driving circuit. For rendering one or more of said fuel feed Worms 8 inoperative, each bevelled gear 18 may be carried by a sleeve 44 splined at 46 upon its shaft 20. Each sleeve 44 carries an annular groove 48 engaged by

pins

50, 50 on a lever 52 (see Fig. 1) fulcrumed at 54 (see Figs. 2 and 3). By said lever 52 said sleeve 44 and gear 18 can be moved to throw gear 18 into or out of mesh with gear 22 to render the corresponding fuel feed worm operative or inoperative (see Fig. 3 and middle feed worm in Fig. 1).

The invention contemplates the provision of simple and efficient means to provide a measure for the total amount of fuel delivered to the combustion chamber of the furnace by all the fuel feed worms that are in operation. In the illustrative embodiment of the invention, said means comprises a fan or blower 56, see Fig. 1, connected at its suction side to one end of a pipe 58 and at its delivery side to one end of a pipe 60, the free ends of said

pipes

58 and 60 being closed. Said fan 56 is herein positively driven by shaft 30 through suitable connections (not shown) of conventional construction.

Pipes

58 and 60 are connected by as many connecting pipes 64 as there are fuel feed worms. In each of said pipes 64 there is provided a restriction or throttling edge 66 and a valve 68 which may be of any conventional construction that is suitable. In the pipe 58, before its connection with the suction side of the blower there is provided a restriction, preferably a throttling edge 62. When said blower or fan 56 is in operation, the pressure of the air delivered by the fan will be proportional to the square of the number of rotations of said fan. At each of the throttling edges 66 however, a fall in pressure will be created which is proportional to the square of 100 the quantities of air permitted to pass through said throttling edges 66. Since however, the pressure in front of said throttling edges is proportional to the square of the number of rotations of the fan 56, the total amount of air per- 705 mitted to pass through the throttling edges 66 will be directly proportional to the number of rotations or revolutions of the fan 56. This total amount can again be measured at the throttling edge 62 in the pipe 58. If, therefore, all of the 110 fuel feed worms 8 are in operation, and correspondingly all of the valves 68 open, then the number of revolutions of the motor 32 will be proportional to the entire amount of fuel fed to the furnace. The number of revolutions of the` are in operation and all of the valves 68 are open..

The amount of air, however, which passes through a throttling edge in a tube, besides being proportional to the 'square root of the pressure differential is proportionalto the opening in said throttling edge. It follows therefore that the amount of air which flows through the pipe 58 to the suction side of the fan 516 and consequently flows through the throttling edge 62 must be proportional to the sum of the openings in the throttling disks 66. If, therefore, one or more of the connecting pipes 64 be cut off by closing the valves 68 therein, then the amount of air flowing through the throttling disk 62 will be diminished in an amount corresponding to the number of said connecting pipes 64 out off. In the illustrative embodiment of the invention for example, wherein there are three fuel feed worms, if one of said worms be rendered inoperative and one of said connecting pipes 64 be cut off, then there will flow through said throttling edge 62 only two-thirds of the amount of air which would flow through it if all of said connecting tubes were open.

Since as explained the amount of air fed or propelled through the main throttling edge 62 is dependent upon the number of revolutions of the fan 56 and therefore on the number of revolu- .tions of the motor 32 for driving the fuel feed worms, as well as dependent upon the number of the connecting pipes 64 that are open, it will be apparent that the amount of air flowing through said main throttling edge 62 will in fact furnish a measure proportional to the amount of fuel fed by all of the fuel feed worms that are in operation at any given time, providing that a connecting pipe 64 is open for each fuel feed worm that is in operation, i. e. connected to the motor 32 and that for each fuel feed Worm that is not in operation, i. e. is disconnected from said motor, -a connecting tube 64 is closed.

The valves 68 may be operated in any suitable manner, handles or levers 70, one for each valve being herein provided for that purpose for opening or closing the valves, one of said levers being shown in Fig. 2. In order to insure that each valve shall be opened or closed simultaneously with the rendering operative or inoperative of its corresponding fuel feed worm 8, each of said handles or levers 70 may conveniently be connected by a link 72 or the like with the operating lever 52 for rendering its corresponding fuel feed worm 8 operative and inoperative.

Referring to Fig. 2, a jet nozzle '13 is provided from which there issues a continuous jet of pressure fluid, air or oil for example under pressure supplied thereto from any suitable source, not

shown. Said nozzle 'I3 is pivoted at 74 and opposite the outlet orifice thereof there are disposed the open ends of two pipes 76 and '78 which communicate with oppositeends of a cylinder 80 in which works a piston 82 carrying the electrical contact 42 above referred to which cooperates with the above mentioned resistance 40,

The difference of pressure produced in the ypipe 58 by means of the restriction of throttling edge 43 is transmitted through

pipes

84 and 86 to differential pressure responsive means herein comprising a diaphragm chamber 88 containing a diaphragm 90, said

pipes

84 and 86 communicating with said diaphragm chamber at opposite sides of said diaphragm. Means is provided to transmit movement of said diaphragm 90, due to variations in said pressure difference, to said nozzle 73, to vary the position of its discharge orifice relative to the open ends of said pipes 76 and '18 and thus to supply more pressure fluid to the one than to the other of said pipes, whereby to move the piston 82 and said contact 42 in the one or the other direction longitudinally of said resistancev 40 to throw more or less thereof into the l motor energizing circuit and thus vary the number of revolutions of said motor and the amount of fuel fed. Preferably said means comprises a rod 92 havingone end acted upon by said diaphragm 90 and its other end acting upon said nozzle 72. This it may do directly but in the lllustrative embodiment of the invention, said rod 92 is adapted to act through a lever 94 fulcrumed at 96. Between said lever and said nozzle there will preferably be provided a member 98 carried by a sliding rod 100. The point of contact of said member 98 may thus be adjusted in different positions longitudinally of said lever 94 thus to vary the throw imparted by movement of said diaphragm to said nozzle '73.

From the above description it will be obvious to those skilled in the art that variations in the pressure difference referred to effects a regulating action upon the fuel feed.

A suitable pipe 102, diagrammatically shown in Fig. 2, leads from the combustion chamber of the furnace to pressure responsive means, herein comprising a diaphragm chamber 104 containing a diaphragm 106, said pipe opening into said diaphragm chamber 104 at the right side of said diaphragm referring to said Fig. 2. Said diaphragm 106 acts at its other side through a rod 108 or other suitable means, upon said nozzle '73 in opposition to the action upon the latter by the diaphragm 90. Assuming the furnace to be operated with natural suction draft, the pressure of the combustion air supplied to the furnace transmitted through said pipe 61 will effect a regulating action upon the fuel feed through diaphragm 106, rod 108, nozzle 72, cylinder 80 and relatively movable contact 42 and resistance 40.

From the above description it Will be apparent that fuel feed regulating means, herein comprising said relatively adjustable contact 42 and resistance.40 is acted upon on the one hand by a pressure proportional to the amount of combustion air in the combustion chamber of the furnace and on the other hand by a pressure difference which is proportional to the quantity of air flowing through said throttling edge 62, said pressure from said combustion chamber and said pressure difference acting through their respective diaphragms upon said nozzle, by the resultant movement of the discharge orifice of which relative to the open ends of said two pipes 76 and 78 a greater quantity of compressed air, oil or other fluid will pass to one side of the piston 82 than to the other, correspondingly to move said piston and contact 42 relative to said resistance 40.

Briefly the operation is as follows:

Referring to Fig. 1, should the proportion of combustion air to the amount of fuel fed to the combustion chamber of the furnace vary from the correct one from any cause, should for example the proportion of fuel fed to the furnace become too great, then the pressure difference to which the diaphragm is subjected and which is proportional to the quantity of fuel fed, will preponderate over the pressure derived from the combustion air and acting oppositely upon the diaphragm 106. Consequently nozzle 73 will be swung clockwise about its pivot 74 and more pressure fluid will thus be supplied to pipe 76 and less to pipe 78. Piston 82 will consequently be moved upwardly and a greater section or length of resistance 40 will be included in the energizing circuit of motor 32. This results in a reduction in the number of revolutions of said motor and of the fuel feed worms driven thereby, and in a corresponding decrease in the fuel fed to the furnace. Furthermore the speed of revolution of the fan or blower 56 and consequently the quantity of air propelled thereby will suffer a proportional decrease, thus diminishing the pressure difference acting upon the diaphragm 90, and such diminution will continue until a state of equilibrium shall have been established between the opposed actions of

diaphragms

90 and 106. When such a state of equilibrium is reached the right proportion between fuel and combustion air to secure the greatest possible efhciency of combustion will have been established.

Should the quantity of combustion air and consequently the pressure acting upon diaphragm 106 increase, the reverse operation will take place. fn either case the fan or blower will always feed a quantity of air exactly proportional to the quantity of fuel fed to the furnace at any time, and therefore furnish an exactly proportional air quantity value, and this quite irrespective of how many of the fuel feed worms are thrown into or out of operation, providing that for each fuel feed worm cut out a connecting pipe 64 be closed off and for each fuel feed worm thrown into operation a connecting pipe 64 be opened.

It will thus be apparent to those skilled in the art that the invention provides for a combustion regulation, herein by regulating the fuel and combustion air supply relative to each other, so as to maintain at ali times a proportion of fuel to combustion air supply and hence a combustion regulation, capable of securing a combustion that shall be as favorable and efficient as possible at all times, and this irrespective of any changes that may be made or which may occur from any cause in the amount of fuel supplied to the furnace, in the illustrative embodiment of the invention for example by throwing one or more of the fuel feed worms into or out of operation.

If the various fuel feed worms 8 each have the same fuel feeding capacity, which would generally be the case, then all the throttling edges 66 should have the same cross section, On the other hand, if the fuel feeding capacity of said fuel feed worms differs then the cross sections of said throttling edges should vary in the same relation.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment of the invention to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. Combustion regulating apparatus for furnaces comprising, in combination, a plurality of burners; a plurality of fuel feeding devices to supply fuel to said burners; driving means for said fuel feeding devices; single means to effect a regulating action controlled by said driving means in accordance with the quantity of fuel supplied by said fuel feeding devices; means to vary the number of said fuel feeding devices that are operative and to control said regulating action effecting means in accordance with the amount of fuel supplied by the number of fuel feeding devices in operation at any time; means to effect a regulating action responsive to tho combustion-air pressure in the furnace; and combustion regulating means controlled by the regulating effect produced by said two regulating action effecting means.

2. Combustion regulating apparatus for furnaces comprising, in combination, a plurality of burners; a plurality of fuel feeding devices to supply fuel to said burners; driving means for said fuel feeding devices; pneumatic means comprising a measuring fan controlled by said driving means in accordance with the quantity of fuel supplied by said fuel feeding devices; means to vary the amount of air fed by said fan in accordance with the amount of fuel supplied by the number of fuel feeding devices in operation at any time; means to vary the number of said fuel feeding devices that are operative; means to effect a regulating action responsive to the combustion-air pressure in the furnace; and combustion regulating means controlled by the delivery of said fan and by the regulating effect produced by said regulating action effecting means.

3. Combustion regulating apparatus for furnaces comprising, in combinatioma plurality of burners; fuel feeding devices to supply fuel to said burners; driving means for said fuel feeding devices; pneumatic means to effect a regulating action comprising a measuring fan controlled by said driving means dependent upon the amount of fuel passing through said burners; means to vary the number of said fue] feeding devices that are operative and to control the regulating action effecting means in accordance with the number of fuel feeding devices in operation at any time a pipe for receiving the fluid exhausting from said fan; means to effect a regulating action responsive to the combustion-air pressure in the furnace; and a fuel feed regulator controlled by the fluid from said fan and by the regulating effect produced by said regulating action effecting means.

4. Combustion regulating apparatus for furnaces comprising, in combination, fuel feeding devices to supply fuel to the furnace; means to effect a regulating action; means to vary the number of said fuel feeding devices that are operative and to control said regulating action effecting means in accordance with the amount of fuel supplied by the number of fuel feeding devices in operation at any time; means to effect a regulating action responsive to the combustionair pressure in the furnace; and regulating means controlled by the regulating effect produced by said two regulating action effecting means relatively to regulate the fuel and combustion-air supplied to the furnace.

5. Combustion regulating apparatus for furnaces comprising, in combination, at least two burners; a fuel feeding device for each burner for supplying fuel to the furnace; driving means for said fuel feeding devices; a common measuring fan for said burners controlled by said driving means dependent upon the amount of fuel passing through said burners; a pipe for receiving the air exhausting from said fan; means to vary the number of said fuel feeding devices that are operative and the amount of air exhausted by said fan; means to effect a regulating action controlled by the combustion-air pressure in the furnace; and a fuel feed regulator controlled by the fluid from said fan and by the regulating effect produced by said regulating action effecting means, said regulator comprising a jet nozzle controlled by fluid pressure responsive means and actuating a control for the fuel feed.

6. Fuel measuring apparatus for furnaces or the like comprising, in combination, fuel feeding devices to supply fuel to the furnace; pneumatic means comprising a fan, an air feed pipe connected to the suction side and another pipe connected to the exhaust side of said fan, said two pipes connected by a number of tubes equal in number to that of said fuel feeding devices, said air feed pipe and said tubes each containing a restriction; means to render inoperative one or more of said fuel feeding devices and to cut out a corresponding number of said tubes; and driving means for said fuel feeding devices and said fan controlled by said pneumatic means.

7. Fuel measuring apparatus for furnaces or the like comprising, in combination, fuel feeding means comprising a feed worm; means comprising a gear system to drive said feed worm; means to exert a measuring action upon the fuel feed comprising a pipe; a valve in said pipe; and common means. to throw said gear system out of mesh and close said valve.

8. Fuel measuring apparatus for furnaces or the like, comprising, in combination, fuel feeding devices to supply fuel to the furnace; driving means for said fuel feeding devices; means to exert a regulating action upon said driving means, comprising a number of tubes, one corresponding to each fuel feeding device; a valve in each of said tubes; means to render said driving means operative and inoperative in respect to one or more of said fuel feeding devices and to close and open the valve in the corresponding tube or tubes.

9. Fuel measuring apparatus for furnaces or the like comprising, in combination, fuel feeding devices; driving means for said fuel feeding devices comprising a gearing for each feeding device; means to exert a measuring action upon said driving means, comprising a number of tubes,

., one corresponding to each fuel feeding device; a

valve in each of said tubes; means to throw the driving gearing of one or more of said feeding devices into and out of mesh and to close and open the valve in the corresponding tube or tubes.

10. Fuel measuring apparatus for furnaces or the like comprising, in combination, a combustion chamber; a plurality of burners for said combustion chamber; feeding devices for continuously feeding fuel to said burners; a common driving motor for said feeding devices; means for operatively connecting one or more of said fuel feeding devices to said driving motor and for disconnecting one or more of said devices therefrom; a blower positively driven by said driving motor; a pipe connected to said blower through which air supplied by said blower flows; means to vary in conformity with the number of fuel feeding motor the quantity of air driven through said pipe by said blower; and means for measuring the quantity of air blown through said pipe by said blower.

11. Fuel measuring apparatus for furnaces or the like, comprising, in combination, a combustion chamber; a plurality of burners for said combustion chamber; feeding devices for continuously feeding fuel to said burners; a common driving motor for said feeding devices; means operatively to connect one or more of said fuel feeding devices to said driving motor and for disconnecting one or more of .said devices therefrom; a blower positively driven by said driving motor; a pipe communicating with the suction side and a pipe communicating with the delivery side of said blower; a number of tubes equal to the number of said fuel feeding devices and connecting said two pipes;means for closing said tubes; and means for measuring the total amount of air flowing through said pipe communicating with the suction side of said blower.

12. Fuel measuring apparatus for furnaces or the like comprising, incombination, a combustion chamber; a plurality of burners for said combustion chamber; feeding devices continu- 1 ously to feed fuel to said burners; a common driving motor for said feeding devices; means operatively to connect one or more of said fuelv feeding devices to said motor and for disconnecting one or more of said devices-therefrom; 1 a blower positively driven by said driving motor; a pipe communicating with the suction side and a pipe communicating .with the delivery side of said blower; a number of tubes equal to the number of said fuel feeding-devices and con- 1 necting said two pipes; valves, one in each of said tubes, each of said valves being positively connected to the means for operatively connecting and disconnecting a fuel feeding device with said motor so that upon disconnecting one of 1 said fuel feeding devices from said motor the valve in one of said tubes will be closed; and means for measuring the total amount of air. flowing through said pipe communicating with the suction side of said blower. A

13. Fuel measuring apparatus for furnaces or the like, comprising, in combination, a combustion chamber; a plurality of burners for the latter; feeding devices vcontinuously to feed fuel to said burners; a common driving motor for said tubes, each of said valves being positively connected to the means for operatively connecting a fuel feeding device to and disconnecting it from said motor, so that upon disconnecting one of said fuel feeding devices from said motor the valve in one of said tubes will be closed; 1 a throttling device in each of said tubes; and means for measuring the total amount of air flowing through said pipe communicating with the suction side of said blower.

14. Fuel measuring apparatus for furnaces or the like comprising, in combination, a combustion chamber; apluralityof burners-for the latter; `feeding devices continuously to feed fuel to said burners; a:common driving motor for said feeding devices; means operatively to con- 1 a fuel feeding device to and to disconnect it from said motor, so that upon disconnecting one of said fuel feeding devices from said motor the valve in one of said tubes'will be closed; a

throttling device in each of said tubes; a con.

strction in said pipe which communicates with the suction -side of said blower; and means responsive tothe pressure differential created at said constriction. connected to the means operatively to connect Y GUiDo WNscH.