US1458419A - Automatic combustion regulator - Google Patents

Description

June 12, 1923.

L. E. JONES ET AL AUTOMATIC COMBUSTION REGULATOR Filed April 5, 1920 3 Sheets-Sheet 1 June 12, 1923.

L. E. JONES ET AL AUTOMAT IC COMBUSTION REGULATOR Filed April 5, 1920 3 Sheets-Sheet 2 gnue'nfow June 12, 1923. 1,458,419

. L. E. JONES ET AL AUTOMAT I C COMBUSTION REGULATOR Filed April 5, 1920 I s Sheets-Sheet 5 P L |Ti I I I fi. I I T I i 1 I 3.31: l i k 5 M Q i l I l k i i I I l x E flit. &

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DDNHIHHII H I I I Patented June 12, 1923.

, UNITED STATES PATENT OFFICE.

LABAN ELLsWonrH JONES AND oHAnL s BOSWOLD WRAITH, or ANACONDA,

\ mournun.

AUTOMATIC COMBUSTION REGULATOR.

Application filed April 5, 1920. Serial No. 371,540.

. specification.

automatic regulation of combustion in combustion chambers. I

The main object of this invention, generally stated, is to provide an apparatus which will at all times and under all influencing conditions automatically control the feed of fuel, such as pulverized coal, oil, orgas, the supply of oxygen (air), the draft, or all as stated, in the combustion chambers of metallurgical and industrial furnaces, ovens, and boilers, so as to accomplish and maintain a balanced combustion, complete or partial as desired A further object. of this invention is to provide an apparatus whose novel arrangement, construction and combinationof parts furnish automatic means for the operation control, or regulation of other mechanical devices to which the motion transmitted by this apparatus is applicable and to which the impulse governing the operations of this apparatus is an influencing factor.

For the purpose of discussing the main object of this invention, namely the automaticregula-tion and control of combustion in combustion chambers, We will consider its application to reverberatory smelting furnaces to which application the apparatus has been developed to its present stage.

It is a well determined fact that combustion in such a furnace is disturbed by the slightest variations in draft pressure, which variations result from changes in atmospheric conditions. opening and closing of doors and ports to the furnace, dropping charges, and numerous other causes and conditions. The combustion mixture is changed to an extent where an excess of air oran excess of incompletely burned products of combustion are prevalent. This unbalanced condition. results in a waste of heat, poor fuel eliiciency, spasmodic increase and decrease of temperature with the resultant working of the chamber roof and settings by inefficient operating This invention relates to apparatus for the expansion and contractionand generally an condition. Further than this an incomplete combustion contributes to a poor heat distribution which decreases smelting efliciency as-a consequence. I

This invention when installed in connection with a metallurgical furnace, burning pulverized coal, oil, or gas, operates to automatically increase or decrease the fuel, the oxygen, or both as required for a proper combustion mixture; according to the slightest variation of draft pressure,

The fuel is blown into the furnace through burner pipes by air under compression. This air supply, commonly referred to as primary air usually amounts to, in the case of pulverized fuel, less than 50% of the total .air required for a complete combustion of the fuel supplied. The balance of the air necessary for a proper combustion mixture is drawn into the furnace by' the injector effect of the primary air flowing through the burner pipe and the draft of the furnace.

The fuel feeding' mechanism, in the case of pulverized coal and the valves in the case of oil or gas are usually adjusted for a fixed rate of fuel feeding. The air-,primary and secondary, for the combustion of the fuel is likewise a fixed amount, dependent on the port openings T he draft, the other or third factor in the combustion,- is a variable throughout a considerable range. because of causes -previously mentioned. It can be readilyseen that, for instance where there is an increase in draft pressure, the fuel and air supply being. fixed, an excess of secondary air is drawn into the furnace by reason of this increase of draft pressure.

This excess of air requiring heatnnits tobring its temperature up to the temperature of the escaping gases robs the furnace of just this amount of heat. Also by reason of this increase in draft pressure the velocity of the gases leaving the furnace is greaterwith the result that the furnace is robbed of heat units it can ill afford to lose.

The reverse of this condition is a decrease of draft pressure which acts to cause a decrease in the amount of secondary air drawn through the air ports into the furnace thus resulting in an insufiicient quantity of oxyice gen entering the combustion chamber to completely consume the fuel supplied. This in= complete combustion of the fuelresults in a gas carrying free carbon monoxide, which passes out of the furnace into the flue system where it obtains oxygen from the air 3 leaking through the settings and from open doors, and burns with the generation of a high heat where it is least desired. 1'? When such conditions as these are noted .by the furnaceman he attempts to regulate 1 by operating the adjustment of the fuel feeding mechanism by hand to give more or less fuel as required or he opens or closes the air ports to give more or less air as required.

The accuracy of such regulation is based l solely on the ability of the furnaceman to judge conditions from observation. The

disadvantages of this method of regulation are many.

It is'o'bvious that some automatlc means of constant regulation and control is highly \desirable and would result in, not only a saving of fuel but also in a smooth steady operating condition and numerous other benefits which only a man familiar with the operations of metallurgical furnaces can fully appreciate; hence the development of an automatic combustion regulator as is herein described;

For a full understanding of the invention reference is had to the accompanying drawings inwhich I Fig. 1 is a plan View;

Fig. 2 a front View of a device representing one embodiment of the invention;

Fig. 3 another embodiment thereof; and r Fig. 4c is a detail view on a larger scale of part of the mechanism disclosed in Figs. 1 and 2.

The operating mechanism constituting the form of the invention shown in Figs. 1 and 2 is contained in a casing 1. A draft pressure indicating and recording means of the type forming the subject matter of my application Serial No. 367,458 filed March 20, 1920 comprises a pan receptacle 3 which contains a light liquid, preferably oil, for sealing purposes and through the center of which protrudes a draft .pipe l to a sufficient .height to clear the surface of the liquid. A pan 5 of smaller diameter than the receptacle hangs bottom side up in the sealing liquid thus forming a closed chamber sealed by the liquid, the only. communication to this chamber being the draft pipe 4c.

The inverted pan 5. is suspended-from a chain 6 connecting it to a system of levers 7 and 8 and is counterbalanced by weights around a knife-edge center. \Veight 9 acts as a counterbalance for the parts operating around the knife-edge center while weight 10 acts to counterbalance any force exerted upon pan 5 or in other words acts to counterbalance or weigh the draft pressure. To the lever system is attached arm 11 carrying a pen for the purpose ofindicating and recording the draft pressure on the calibrated chart 12 revolved by means of a constant speed motor such as a clock mechanism 13.

In order to make thedevice thus far described available for automatically controlling the fuel feed mechanism we provide the following means:

The lever or arm 8 preferably includes two springarms l4: and 15 carrying contact points 14:" and 15", respectively, mounted on iron armatures 14c and 15.

About the axis of the lever 8 is revolubly mounted another arm 16 carrying at its lower end upon an insulating bar 16 two small magnets 17 and 18 provided with contact points 17 and 18. As is shown more clearly in detail in Fig. 4:, these contact points 17 and 18 are positioned to move in the same plane of angular motion as the contact points 1a and 15 respectively and to make contact therewith. Screws 19 and 20 may extend through the magnets to define the contact points l'land 18 and afford adjustment thereof in the well known manner.

The'magnet 17 isenergized by a winding 17 and the magnet 18 by a winding 18 when contact is established between contacts l7 and 14:" or 18 and 15", respectively, for a purpose to be subsequently re-- ferred to.

One pole of the battery is connected to the spring arms 14:, 15 through connection 7 and levers? and 8, while the other pole of the battery is connected through conductor 43 to one terminal of the solenoids 21 and 22. The other terminals of solenoids 21 and 22 are connected through conductors 44 and 45 to the windings 17 and 18" respectively.

The free end of the winding 17" is connected to contact point 17' and the free end of the winding 18" to the contact point 18. Motor 23 which preferably is a three-phase alternating current motor is gearedup with a shaft 2 which controls through. sprocket 24 the fuel feeding mechanism (not shown). Through stationary contact posts 25, 2G, 27, 28, movable contact posts 29, 30 and 31, 32 carried by the plungers21 and 22 respectively, and connections 33, 34c, 35, 36 and 37 the motor is caused to run in one direction When the plunger 21 is operated and in opposite direction when plunger 22 is operated.

Upon shaft 24', which is so geared with the motor 23 as to obtain a large reduction in speed, travels a nut 38 one way or the other according to whether the fuel feed is increased or decreased. This nut is pivotglsly connected to the arm 16 by a rod or link The operation of the device is as follows: Assuming that the draft pressure increases or decreases from normal indicated on the chart 12 by the Zero line, the arm 8 will swing in one case to the left, in the other to Inc the right or vice versa and will eventually cause contact between the contact points 14 and 17 or 15" and 18". Just as soon as contact is made current will flow from the battery through winding 17 and solenoidQl or through winding 18" "and solenoid 22, as the case may be, causing the motor to be run in one direction or the other.

Once a magnet 17 ,or 18 is energized, it tends to take the corresponding armature 14 or 15' along when the arm 16 is moved by the nut 38 through the link 38. The spring arms 14 and 15 are so constructed as to angularly yield a definite amount before they break contact with the magnets. By

properly designing the resistance of the arms 14 and 15 against bending, the windings 17 and 18" or both and by adjusting the screws 19 and 20, the feed control may be made accurately responsive and sensitive. The time required for the magnet to move from its position of making contact to its position of breaking contact is the time necessary for the operation of the feed control means and this time may be accurately determined by the means disclosed.

After the contact between one of the arms 14 or 15 and the corresponding magnet 17 or 18 is broken, the motor stops. the draft pressure changes and the other of the spring arms contacts with the other magnet, the other solenoid will be energized and the motor will be operated in reverse direction;

In Fig. 3 is represented a device which,

'is used to regulate to maintain a substantially constant draft pressure. lt is obviously possible to maintain a substantially constant supply of fuel or combustion mixture and by keeping the draft pressure substantially constant a balanced steady combustion is ebtained.

The arrangement represented in Fig. 3 is generally the same as that shown Figs. 1 and Q, with thedifierence, however, that the motor 23' and the shaft 24 driven thereby are located a distance from the other mechanism. The shaft 24 is connected to a damper 30 controlling the flue 31 or other conduit through which the air passes to the combustion chamber. It is understood the motor may be connected to any other draft-controlling device, the particular an rangement being referred to only for purposes of illustration;

' accurately responsive.

As soon as to normal. By properly correlating the spring arms14, 15 the magnet windings 17 18", the ratio of the reduction gearing, etc., the draft control may be made sensitive and Various refinements obvious to persons skilled in the art, may of course be introduced to make the draft adjustment smooth i. e. to prevent overshoot- 'ing and corresponding fluctuations of the draft pressure. lhe arrangement shown and described, however has been found to give complete satisfaction.

It is obvious that the draft regulator may be easily applied also to installations in which artificial draft is used. In such cases the motor will be used simply to adjust the speed of -the blower motor or other pressure device in the well known way.

It should be understood that the specific arrangement constitutes only one embodiment of the invention, although this form is at present considered as a preferred form. The important feature in its broader aspect is time controlled means operative upon con tact between the arm 8, or other pressureres'ponsive element, and either one of the contacts 14", 15K, to maintain contact for an appreciable length of time. The a ange ment essentially includes two important features:

(1) Means operative upon contact to POSltively maintain contact;

(2) Means operative upon contact to make the holding action ineffective after a definite time interval.

While we prefer the use of spring blades as partof arm 8 and a movable element such as nut 38 acting upon the support of the magnets to move them relatively to arm 8, the time interval may be introduced in various other ways and it is emphasized that we do not intend to limit ourselves to the particular form of embodiment disclosed.

While we have described two embodiments of the invention, one in which the feed of l such arrangement we contemplate as within the scope of invention. In fact the movement of the pressure gage may be translated to regulate dependently or independently any factor entering into the process of combustion.

In the foregoing the various elements have been referred to without accounting 'for their specific structural relation and support. lt is obvious that there is considerable latitude in the arrangement. In the drawings is shown a frame composed of upright frame members '40 and transverse members 41 and 42 for pivotally supporting the lever system 7, 8, arm 16, shaft 24 and other parts.

The connections from the motor 23 to the source of power and to the switch mecha-' nisms are not described in detail since they are a matter of common knowledge and well understood by persons skilled in the art.

-We claim:

1. In apparatus of the character described, the combination with a pressure responsive means including a pivotally mounted element and means for translating variations of pressure into angular movement of said element and means for regulating conditions in a combustion chamber including an electric motor and electric circuits for controlling the motor, of an arm connected to the said elementand partaking of said angular movement, contact elements disposed on oppositc sides of the arm in the plane of movement thereof, said arm being adapted to contact with said contact elements, means operative upon contact between the arm and either of said contact elements to apply a forcesufiicient to hold the arm to the contact element against a predetermined-force tending to break contact, said circuits being controlled by the said arm and the said contact elements and time-controlled -means operative to make said holding force ineffective.

' 2. Apparatus according to claim 1 in i which the force is applied by a magnet associated with each contact element and the arm carries armatures co-operating with the magnets.

3. Apparatus according to claim 2 in which the magnets are electro-magnets energized by windings connected to said circuits.

4. Apparatus according to claim 1 in which the arm forms a part of said circuits.

5. Apparatus accordmg to claim 1 in which the arm includes resilient means permitting-a limited angular movement of the arm during contact between the arm and either of the contact elements.

6. Apparatus according to claim 5 in whichthe res-ilient means comprises spring blades on the arm, each blade carrying an armature. v

7. Apparatus according to claim 1 in which the circuits include electromagnetic means, the motor and the said electro-magnetic means being so related that when one of the circuits is energized the electromagnetic' means therein will cause the motor to run in one direction and when, another circuit is; energized the electromagnetic means therein will cause the motor to run in opposite direction:

8. Apparatus according to claim 1 in,

her and in the plane of movement thereof, said contact elements adapted to contact with said member, means operative upon contact between the said member and either of said contact elements to apply a force tending to hold them in contact, resilient means for permitting a limited movement of said member while the latter and either of the contact elements are in contact and means operative upon contact between the said member and either one of said elements to move the latter to cause a. breaking of contact.

10. In apparatus of the character set forth, the combination with a. draft gauge having a movable element, a spring blade element connectedto said movabl element, contact elements located on opposite sides ofthe spring blade element and supported for movement in the direction of the movement thereof, a source of electricity, a connection between one pole of said source and the spring blade, a connection between the other pole and each of said contact elements, electromagnetic means in series with .each contact element, means tending to hold the spring blade mechanism in contact with either of the said contact elements, a motor, circuits therefor including a switching mechanism connected with each of the electromagnetic means for operating the motor in opposite directions and means responsive to the action of the motor for moving the contact elements relatively to the spring blade mechanism and out'oi contact therewith.

, 11'. Apparatusaccording to claim 10 in which the means responsive to the action oi the motor comprises a nut traveling upon a screwthreaded shaft driven by the motor and connected to the contact elements.

12. The combination with a combustion chamber and a draft gauge connected therewith, of means for altering the conditions in the combustion chamber and mechanism responsive to the action of the draft gauge for actuating said means, said mechanism including a motor, a, shaft interconnecting the motor and the said means, electric circuits for operating the motor in opposite directions, switch mechanisms in said circuits,

separate means for operating said switch mechanisms, said switch opera-ting means comprising an electro-magnetic means connected to each switch mechanism, a source of electricity, a circuit including the source and one of said electromagnetic means, a circuit including the source and the other of said electromagnetic means, means carried by the draft gauge for, opening and closing either of said circuits and means operative incident upon the closing of one of said circuits to maintain it in closed condition for a sufficient period of time to actuate said means for altering the conditions in the combustion chamber,

13. In apparatus of the character described th combination with pressure re sponsive means including a movably mount-- ed member and means for translating varia- 5 tions of pressure into movement of said member, electrical contact elements on opposite sides of the movable member in thepath of motion thereof, means for regulating conditions in a combustion chamber including an electric motor and electric circuits for controlling the motor, one of said circuits including said movable member and one of said contact elements and another of the said circuits including the movable member and the other contact element, means opera- LABAN ELLSl VORTH JONES.

CHARLES ROSWOLD WRAITH.

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