US1837923A

US1837923A - Automatic fuel

Info

Publication number: US1837923A
Authority: US
Publication date: 1931-12-22
Anticipated expiration: 1948-12-22

Description

Dec. 22, 1931.

c. H. QUINN AUTOMATIC FUEL, DAMPER, AND STACK CONTROL Filed June 25, 1925 2 Sheets-Sheet l a 6mm;

l I I l I l l I l Dec. 22, 1931. H. gu umm 1,837,923

AUTOMATIC FUEL, DAMPER, AND S TACK CONTROL Filed June 5, 1925 2 Sheets-Sheet 2 Ziwuzntov Cfiarles H. Ouzlnn aesaaza s n. ovum, or sen rmcrsco, cronmn AUTOMATIC FUEL, DAMPER AND STACK CONTROL Application filed .Tune 25,

This application is a continuation in part of my patent numbered 1,695,606, granted December 18th, 1928 on an application filed December 16th, 1924, Serial No. 756,320 and covering pressure and temperatureresponsive furnace control means.

lhe invention relates to control devices for furnaces of power, heating or other plants, and has particular reference to furnaces equipped with power driven fuel feeding means and having means for controllingthe inlet of air, steam or other combustion promoting fluids, and furtherequipped with stack draft control means.

The object of the present invention, is to provide means responsive to manual control or setting or to changes in load conditions, pressure conditions, temperature variations or the like for not only automatically controlling the rate of fuel feeding but regulating the inlet of the combustion promoting fluid means and also adjusting the stack draft control means whereby the generation of heat by the furnace may be kept uniform or varied to meet changes in load or other conditions.

Another object of the invention is to provide control means of this I character in which the various control features are so related, operatively connected and synchronized as to permit the lapse of an appreciable time interval between the actuation of the combustion promoting fluid inlet means and the stack draft control means with respect to one another and to the fuel feeding means whereby to avoid complications which might otherwlse ensue, such as, for instance, back pressure or excessive negatlve pressurein the combustion chamber.

A further object of the invention is to provide control means of this character which will be electrically controlled or operated, the arrangement being such that the mechanism will be thrown into operation in accordance with movement of a primary circuit closer having movement resulting from operation of means responsive to manual setting or changes in conditions in the plantor system of which the furnace forms a part.

1925. Serial No. 3%,590.

means in combination with a constantly driven element for varying the rate of drive of fuel feeding means, the speed change means including a control motor adapted to be energized for rotation of its armature in a selected direction by means of a pri mary circuit closer, a governor mechanism being furthermore provided in association with the circuit closer for controlling the same independently of movement thereof under the influence of the condition change responsive means.

Still another object of the invention is to provide an electric control mechanism including a system of reversible motors, together with circuit closers and electromagnetic relays whereby the closing of the motor circuits and the selection of direction of drive of the motors will be correlated to effect operation of the fuel, air and draft control devices so as to insure the most efficient combustion in the furnace in accordance with and as determined by the requirements of the particular conditions existing in the plant.

A. still more specific object of the invention is to provide mechanism including a primary circuit closer actuated by pawl and ratchet devices operated by electromagnetic means energized by a series of current impulses brought about by condition changes in the plant. v

To these and other ends, the invention comprises the various elements and combinations of elements to be hereinafter described and set forth in the appended claims.

In the drawings? Figure 1 is a diagrammatic view of a furnace equipped with my complete control mechanism, all the parts being shown in a position of rest.

Figure 2 is a detail cross-section through the stack of the furnace showing the damper device therein. t

Figure 3 is a detail view showing an end elevation of the pawl and ratchet mechanimn, 1M

duits 3 for the inlet of air, steam or other combustion promoting fluids. Within these conduits are suitable control valves having operating handles 4 and adapted to control the passage of the fluid or fluids. The furnace is further equipped with a stack 5 within which is mounted some suitable control damper such, for instance, as the one to be described.

While the details of construction of the fuel feeders are not illustrated, it is intended that they all be driven by a rotatable shaft 6 adapted to be rotated at variable speeds, by means to be described, depending upon conditions. I have disclosed a drive mechanism for this shaft including a positively driven, preferably constant speed shaft 7 on which are mounted relatively axially movable conical pulleys 8 having engaged therewith a belt 9 which in turn peripherally engages similarly mounted conical pulleys 10 on the shaft 6. The shafts 6 and 7 are journaled through bearings carried by a pair of members 11 pivotally connected, as at 12, and including arms 13 and 14. The double pulleys provide an edge drive for the'belt 9 and it is obvious that if the arms 13 be moved apart the arms 14 will be moved toward each other, and vice versa, and that in the first instance the contact of the edge of the belt 9 with the pulleys 8 will be nearer the larger portions thereof, while the contact with the pulleys 10 will be nearer the "smaller portions thereof, thus resulting in an increase in the speed of rotation of the shaft 6 with respect to the shaft 7 In the latter instance it is apparent that the conditions will be reversed and that the shaft 6 will be driven at a reduced speed with respect to the shaft 7. The means for controlhug the positions of the arms 13 and 14, and

- consequently the speed of the shaft 6 may conveniently consist of 'a rod 15 having its 7 ends oppositely threaded and engaged through the arms 13, the rod being capable of rotation in one direction or the other to effect the desired adjustment of the arms. In the present instance the operating means for the rod 15 is represented as a reversible electric motor 16 having its shaft carrying a pinion 17 meshing with a gear 18 on the rod.

The control means for this motor is shown as comprising a circuit closer designated generally by the numeral 19 and including a longitudinally movable bar 20 adapted to be moved manually or automatically in response to fluctuations in the current output from a generator driven by the plant. I have shown the member 20 as carrying apointer 21 cooperating with a suitably calibrated scale 22 which may, if desired, be located at a remote point with respect to the furnace so as to give a visible indication as to variations in case the mechanism is intended to operate automatically as the result of changes. The rod 20 may be formed in sections detachably connected as by a latch 20 so that manual operation will be possible, one section having a handle 20" for the sake of convenience.

An important feature is that the scale 22 may be calibrated in kilo volts if the device is used in a generator station, or graduated to indicate horse power, steam pressure, or heating units with regard to other uses, and since the entire, device is controlled by the movement of the rod 20, as will be described, it is conceivable that by having the scale calibrated in accordance with any of the units above mentioned, the member 20 may be moved or set to insure anypredetermined output of energy from the plant.

The operating means for the member 20 may conveniently comprise a pair of

ratchets

20 and 20 screwed on to the threaded end portion of the rod or bar 20 and having their teeth facing in opposite directions. These ratchets are engageable by

pawls

20 and 20, respectively, pivoted on rockably mounted

levers

20 and 20, these levers being pivotally connected with

cores

20 and 20 of

solenoids

20 and 20 suitable springs 20 -being provided for opposing drawing of the cores into the solenoids. When either of these ratchets is rotated the rod or bar 20 will be moved longitudinally. The solenoids are adapted to have current impulses passed therethrough in accordance with fluctuations in the output from a suitable generator forming part of the power plant. It is apparent that any suitablemeans for producing these impulses may be; employed, it being easily conceivable that the same system may be utilized as that discldsed in the above mentioned patent.

The member 20 carries

contacts

23 and 24 which are spaced apart and which are connected by

conductors

25 and 26, respectively, with the motor 16. The remaining terminal of the motor has connected therewith a conductor 27 leading to a suitable source of current, not shown. Located between the

contacts

23 and 24 and adapted to engage with or be engaged thereby, as will be explained hereinafter, is a contact 28 carried by a pivoted arm 29 with which is pivotally connected a rod 30 carrying yielding elements or cushion devices such as the springs 31 and 32 engaging against opposite sides of a lever 33 which is pivoted at one end, as shown at 33.

' 33 and adapted to be moved longitudinally in response to changes in the speed of rotation of the shaft 6. While the speed responsive means need not be directly mounted on the shaft 6, I have shown a structure including fly-weights carried by arms 36 pivoted on a slidable sleeve 37, which arms have connected therewith links 38 connected with a sleeve 39 fast on the shaft 6. The arrangement of this governor is such that when the speed of the shaft 6 increases, the rod 34 will be moved to the right, whereas when the speed of the shaft is decreased the rod 34 will be thrust to the left. The above mentioned source of current is connected By a conductor 40 with thecontact 28., The parts thus far described constitute the means for regulat-' ing the rate of feed of fuel to the furnace.

In order that the valves in the conduits 3 may be adjusted for regulating the flow of combustion promoting or supporting fluids to the furnace or burners thereof, I provide a longitudinally shiftable rod member 41 having link connections 42 with the series of valve handles 4. At one end, this rod 41 is pivotally connected at 43 witha floating lever 44, to an intermediate point 45 of which is pivotally connected a link 46 in turn pivotally connected with the free end of the lever 33. Pivotally connected with the floating lever 44 at its end opposite that having the pivotal connection 43, is a rod 47 telescopically or otherwise sl'idably engaged with an extension 48 on a member 49 having spaced contact points 50 and 51 located at opposite sides' of a contact 52 with which is connected a conductor 53 leading to the same or another suitable source of current, not shown. A spring device is provided for yieldably op-' posing relative movement of the members 47 and 49. A portion of the rod 41 is threaded and screwed thereonto is a gear 54 adapted to be driven by a pinion 55 on the shaft of a reversible motor 56 which has one terminal connected by a conductor 57 with the other terminal of the source of current. Another terminal of the motor 56 is connected by a conductor 58 with the contact 50 while the remaining terminal is connected by a conductor 59 with the contact 51. This pontion of the mechanism constitutes the means for controlling the inlet of air, steam or other, combustion promoting fluids to the furnace.

For each increment in the increase of fuel feeding and corresponding increase in the supply of combustion promoting fluid, it becomes necessary, in order to secure the best results, to provide means for corresponding ly regulating the stack draft", It will be observed that I have provided a readily adjustable damper device preferably of T- shape, as shown, or at least including a vertical or upright plate member 60 carried by a plate member 61 which extends transversely with respect to the stack 5, which plate member 61 is slidable for varying the size of the opening or passage 62 defined between the plate 60 and the wall of the stack or stack breeching. For adjusting the position of the damper, I have shown the plate 61 as having an extension 63 slidable within a guide 64 and equipped with rack-teeth 65 meshing with a pinion 66 carrying a gear 67 meshing with a pinion 68 on the shaft of a reversible motor 69. The plate 61 of the damper may be additionally guided by slots or grooves 70 in the stack or stack breech- 111g.

The control for the motor 69 provided for moving the damper, includes a pair of rotatable members or disks 71 and 72 carrying a plurality of contacts 73 and 74, respectively, the corresponding ones of which are connectedby conductors 75 here represented as arranged in loom form for facilitating installation, especially where these control devices are located a considerable distance apart. Pivotally mounted on the members 71 and 72 are contact arms 76 and 77 adapted to engage .the series of contacts 73 and 74, respectively, and designed to act in unison. The contact 77 is rotated by the motor 69 in any suitable manner as for instance by means of a flexible member 78 engaging suitable drive elements carried by the journal of the arm 77 and gear 67. The exact mode of driving is a trivial detail and the means disclosed is simply for pur oses of illustration as it is easily replaceab e by an equivalent. In order that the arm 76 may be rotated in accordance with movement of the shaft or rod 41, I have shown it as carrying a gear 79 with which meshes a rack 80 carried by a rod 81 connected with the rod or shaft 41, as for instance at thepivot point 43. Obviously, when the member 41 is moved by rotation of in the conduits 3, the arm 76 will be correspondingly moved so as to pass over the contacts 73.

Use is also made of an electro-ma gnetic circuit closer for. controlling the enrgiza tion of the motor 69, and electro-magnetic selectors are also provided for controlling the direction of rotation of the motor 69, de-

"separate source of current from which leads the nut gear 54 for controlling the valves pending upon the directionof movement of a conductor 85 connected with the arm 76.

Positioned adjacent the core of the electrowill be completed through the electro-magseparate windings.

net 82 and the armature 86 will be held out of engagement with the contact 87 so that current cannot flow to the motor 69, but when the arm 76 is moved by the movement of the rod 81 as a result of shifting of the rod or shaft 41 so that the arm 76 is then out of engagement with a contact 73, the circuit through the electro-magnet 82 will be broken and the armature 86 will engage the contact .87 and permit current to flow through the conductor 88 to the motor 69. However, the motor 69 will not be energized until one of the selectors'for controlling the direction is operated.

These selectors include electro-

magnets

90 and 91, each of which is provided with two One terminal of one winding of the electro-magnet 90 is connected by a conductor 92 with a terminal of the motor 69 while the other terminal thereof is connected with a contact 93 adapted to be engaged by a pivoted armature 94 connected with a conductor 95 connected with the samesource of current as the conductor 89 and also connected with a pivoted armature 96 associated with the adjacent electro-magnet 91. One terminal of one winding of this magnet 91 is connected by a conductor 97 with the remaining terminal of the motor 69 while its other terminal is connected with a contact 98 positioned to be engaged by the armature 96 when the magnet 91 is energized. One terminal of the other winding on the magnet 90 is connected by a conductor99 with the conductor 59 while its other terminal is connected by a conductor 100 with one terminal of the other winding on the magnet 91, the other terminal of which winding is connected by a conductor 101 with the conductor 58. By

this arrangement it will be seen that one of the windings of each of the

selector magnets

90 and 91 is in parallel with the motor 56 so that when the motor 56 is energized for rotation of its armature in one direction the magnet 90 will be energized and when the motor is reversed the magnet 91 will be energized. Upon energization of the magnet- 90 the attraction of the armature 94 will cause it to come into engagement with the contact 93, thereby closing the circuit through the motor 69 for effecting rotation of its armature in one direction, and if 'the magnet 91 be energized the attraction of the armature 96 into engagement with the contact 98 feed to the furnace.

will'close the circuit through the motor 69 for effecting rotation of its armature in the opposite direction. In either instance it will be observed that passage of the current through the

conductor

92 or 97 will maintain the

magnet

90 or 91 energized even after the motor 56 is deenergized as the current is still passing through one winding, resulting in holding either the

armature

94 or 96, as the case may be, in engagement with the

contact

93 or 98 until the circuit through the magnet 82 is remade as the result of engagement of the arm 77 with whichever contact 74 is live or energized, depending upon the particular contact 73 engaged by the arm 76.

In the operation it will be seen that if the member 20 remains stationary, as it will when there is'no change in conditions in the furnace, boiler or associated mechanism, the entire control device will be at rest except that the shaft 6 for the fuel feeding means is of course rotating by virtue of its drive connection with the prime mover shaft 7. When the member 20 moves a sufiicient distance in one direction or the other as the result of manual movement or as the result of rotation of the

ratchet

20 or 20 caused by the passage of current impulses therethrough as set forth in said copending application as the result of fluctuations in the current output from a generator forming a major or an auxiliary part of the plant, or as the result of boiler pressure changes, temperature changes or other variations in conditions, it is evident that either the contact" 23 or the contact 24 will be brought into engagement withthe contact 28 of the primary circuit closer. When this is done the circuit is closed through the motor 16 for effecting rotation of its armature in one direction or the other, the direction depending upon whether it is the contact 23 or the contact 24 which is brought into engagement with the contact 28.

Assuming'that a movement of the member 20 to the right indicates a change in conditions requiring the generation of moreheat by the furnace, it will be the contact 23 which engages the contact 28. The motor 16 is then driven in such a direction that it will rotate the gear 18 so that the threaded rod 15 is screwed through the arms 13 to move them apart, the arms 14 being brought correspondingly closer together. Owing to the peculiar conical pulley arrangement it is evident that the edges of the belt 9 will then engage larger portions of the pulleys 8 and smaller portions of the pulleys 10, and this difference in ratio between the driving pulleys 8 and driven pulleys 10 will result in an increase in the speed of rotation of the shaft 6 and consequently an increase in the amount of fuel As the speed of the shaft 6 is increased the fly-weights 35 of the governor mechanism will fly outwardly, an action which will result in moving the r,

eeaeas 34 to the right and swinging the lever 33 in the same direction. The movement of the lever 33 is communicated through the link 46 to the floating lever 44 which, at this time, pivots at the point 43, and the result will be that the member 48 will be moved to the right, the cushion device being'compressed, and the contact 50 will be brought into engagement with the contact 52, thus closing the circuit through the motor 56 and through one winding-on the selector magnet 91.

As the lever 33 swings to the right, as above indicated, the cushion device or spring 32 is compressed until its resistance is such that the link 30 will be moved to the right, resulting in swinging the arm 29 to the right out of engagement with the contact 23, thus break ing the circuit to the motor 16 so that the arms 13 will remain at the proper distance apart for the shaft 6 to continue to be driven at the speed attained. The energization of the motor 56, as above described, will result in driving of the gear 54 which is of course restrained from axial movement and as this gear is screwed onto the threaded portion of the shaft or rod 41, the shaft or rod 41 will be moved to the right and will turn the valve handles 4 for increasing the flow of air, steam or other combustion-promoting fluids to the furnace. At the same time, this longitudinal movement of the rod or shaft 41 causes similar movement ofthe 'rodi81 which terminates in or carries the rack 80 meshing with the gear 79 of the member 71 so that the arm 76 will be moved out of engagement with the contact 7 3 initially engaged thereby whereupon the circuit between the previously engaged contact 73 and the corresponding contact 74 on the member 72 will be broken.

a The breaking of the circuit at this point causes deenergization of the magnet 82 and the armature 86 thereof drops into engagement with the contact 87, closing the circuit through the motor 69, conductor 97, other winding on the magnet 91, and through the armature 96 which was drawn into engagement with the contact 98 upon energization of the exciting winding in this magnet simultaneously with the energization of the motor 56. The instant that the armature 96 engages with the contact 98, the other or second winding on the magnet 91 becomes energized so that the armature will be held in engagement with the contact 98 when the exciting coil is deenergized simultaneously with deenergization of the motor 56, which deenergization occurs when the shaft 41 moves to the right, as above described, to such an extent that the movement of the floating lever 44, then fulcruming upon the pivot 45, causes movement of the member 49 to the left and breaking of the circuit between the contacts 50 and 52. The energization of themotor 69 upon engagement of the armature 96 with the contact 98 results in driving the gear .engagin the rack 63 and the damper will be move so as to increase the size of the passage 62 for the products of combustion.

Energization of the motor 69 and driving of the gearing results in rotation of the arm 77 and as soon as this arm comes into engagement with the particular contact 74 corresponding to and connected with the contact 73 engaged by the arm 76, the circuit through the magnet 82 will be completed and the attraction of the armature 86 thereof will result in breaking the motor circuit at the point 87 so that the motor 69 becomes deenergized. It will be observed that there is or may be more or less of an appreciable time interval between the increase in the speed of rotation of the shaft 6, the opening of the fluid conduit valves and the opening of the damper as it has been found that such is more advantageous than having the three control devices operate simultaneously.

In case the conditions in the plant vary in such a manner that the control element 20 moves in the opposite direction, indicating that there should be a decrease in the heat generated by the furnace, the action is the same except that the contact 24 enga es the contact 28 for closing the circuit to t e motor 16 and energizing it in the reverse direction so that the speed change device including the pulleys and belt will operate to reduce the speed of rotation of the shaft 6. When the speed has been reduced the governor mechanism forces the lever 33 to the left so that the circuit to the motor 56 will be through the contacts 51 and 52, resulting in energization of the motor 56 in such a direction that the rod or shaft 41 will be moved to the left for partially closing the fluid inlet control valves, the circuit being broken between the contact 51 and 52 as soonas the rod or shaft 41 has been moved to the necessary extent. However, energization of the motor 56 in this reverse direction results in completion of the circuit through one coil of the magnet 90 and the armature 94 thereof engages the contact 93 for completing the circuit through the motor 69 so that the damper will be moved to decrease the size of the passage 62 in the stack or stack breeching. The action of the arms 76 and 77 controlling the energization of the magnet 82 is the same as above described, the action being to break the circuit to the motor 69 when the damper has been moved to the necessary extent.

If forany reason the speed of rotation of the prime mover shaft 7 should vary, re-- sulting in corresponding variation in the speed of the shaft 6, it will be obvious that the governor will operate to slide the member 34 in one direction or the other and swing the lever 33 whereby the arm 29 connected therewith will bring the contact 28 into engagement with either the contact 23 or the contact consequentl regulating the variable drive connection tween the shafts 6 and-7 and thus compensate for the change in the speed of the prime mover shaft, the other elements of the entire apparatus acting as above described.

While I have shown and described a preferred embodiment of the invention and while particular reference has been made to certain structural features and mechanical and electrical contrivances, it should be understood that the disclosure is merely for illustrative purposes as the right is reserved to make all such changes in the form, construction and arrangement of parts as will widen the field of utility and increase the adaptability of the mechanism, provided such variations and modifications constitute no departure from the spirit of the invention or the scope of the claims hereunto appended.

Having now described my invention, what I claim is:

' 1. In a furnace control mechanism, the combination of mechanical fuel feeding means, means for driving said means, condition change responsive means for varying the rate of drive of the fuel feeding means,

means for sup lying combustion promoting fluid to the rnace means responsive to said second named means for controlling said fluid supply means, and means operable subsequently to said lastnamed means for controlling the furnace stack draft.

2. In a furnace control mechanism, the combination of mechanical fuel feeding means, means for driving said means, condition change responsive means for varying the rate of drive of the fuel feeding means, means for supplying combustion promoting fluid to the furnace, means responsive to said second named means for controlling said fluid supply means, and correspondingly operable means for controlling the furnace stack draft, the drive rate varying means, the fluid admission control means, and the stack draft control means operating in sequence.

3. In a furnace control mechanism, mechanical fuel feeding means, means for driving said means, condition chan e responsive means for controlling the spe of the driving means, means for supplying combustion promoting fluidto the furnace and means for controlling the furnace stack draft, said third, fourth and last named means operating in sequence, and said fourth and last named means being responsive to said third named means.

4. In a furnace control mechanism, the combination of mechanical fuel feeding means, means for supplying combustion prw moting fluid to the furnace, means for regulating the stack draft of the furnace, means for varying the drive of the fuel feeding means, and means responsive to changes in the speed of drive of the feeding means for sequentially actuating the fluid supply means and draft control means. a

5. In a furnace control mechanism, the combination of fuel feeding means, means for driving said feeding means at variable speeds, means for controlling the speed of said feeding means, and means responsive to variations in the speed of said feeding means for controlling the inlet of combustion promoting fluid to the furnace and means operable subsequently to said last named means for regulating the stack draft.

6. In a furnace control mechanism, mechanical fuel feeding means, a constantly rotating shaft, a variable speed transmission between said shaft and the fuel feeding means, an electric motor operatively connected with said transmission means for regulating the same, a circuit closer for controlling the energization of the motor, and means for operating said circuit closer in response to condition chan es, and motor controlled means for regu ating a supply of-combustion promoting fluid to the furnace controlled by movement of said circuit closing means.

' 7. In a furnace control mechanism, mechanical fuel feeding means, a constantly rotating shaft, '3. variable speed transmission between said shaft and the fuel feeding means, an electric motor operatively connected with said transmission means for regulating the same, a circuit closer for controlling the energization of the motor, means for operating said circuit closer in response to condition changes, motor controlled means for regulating a supply of combustion promoting fluid to the furnace controlled by movement of said circuit closing means, and means operating in conjunction with said last named means for regulating the furnace stack draft.

8. In a furnace control mechanism, fuel feeding means, combustion promoting fluid supply means, stack draft control means, and means adapted to be operated in response to condition changes and to be manually controlled for varying the speed of the fuel feeding means and means responsive to said last named means for sequentially controlling the fluid supply means and stack draft control means.

9. In a furnace control mechanism, fuel 7 electri- "m cally operated means for controllin all of said means in sequence with a time interval between, operable from a remote point and including a combined manual and change responsive circuit closing means.

In testimony whereof I aflix my signature.

CHARLES H. QUINN.