US1820507A - Automatic fuel feeder - Google Patents

Description

R. H. STULL Aug. 25, 1931.

AUTOMATI C FUEL FEEDER Filed Aug. 5, 1927 UNITED STATES PATENT OFFICE ROY H. STULL, OF SUNBURY, PENNSYLVANIA AUTOMATIC FUEL FEEDER Application filed August 3, 1927. Serial No. 210,276.

This invention relates to means for auton'iatically feeding fuel to furnaces and for regulating the furnace dampers. In carrying out the invention, I provide a motor operated conveyor for feeding the fuel to a suitable spreader arranged within the furnace chamber and time-controlled means for periodically operating the motor for a predctern'lined number of minutes, whereby a certain amount of fuel is delivered into the furnace at each operation of the motor. By

means of suitable timing mechanism and intermediate devices, the motor which operates the conveyor may be initially started at any hour in the day, and after a predetermined number of operations, during which a predetermined amount of fuel is fed into the furnace, the circuit'of the motor is automatically interrupted by mechanism driven by the motor. The dampers are automatically controlled so that they may be opened and closed at predetermined times. Thus, ordinarily, the dampers, in a house-heating system, will open automatically at an early hour in the morning, and in a predetermined time thereafter the fuel-feeding device will commence to operate, and the latter will operate at intervals during the day. At a late hour in the evening, the dampers will automatically close while the fuel-feeding device will continue to apply fuel to the furnace for a few periods thereafter, to supply sufficient fuel to hold the fire until the following morning. The fuel feeding mechanism will then cease to function until after the dampers have been automatically opened on the following morning. Means are provided for varying the length of time during which the motor which moves the conveyer will operate, so that the amount of fuel delivered to the furnace at each operation may be regulated.

The fuel-feeding and damper-controlling mechanisms operate the same with steam, hot air or hot water systems of heating, but when applied to steam boilers, as illustrated in the drawing, I provide means whereby on the occurrence of undue rise in steam pressure, a pressure-controlled device will operate the dampers to entirely close the same, and the fuel-feeding mechanism will also be stopped until normal conditions are restored.

The invention is illustrated diagran'imatically in the drawing, in which a indicates the heater of a household heating system, in this instance, represented as a boiler, having a damper 1 below the furnace chamber, and a damper 2 in the smoke pipe 3, and also having a pressure regulating device 4, adapted to rock a lever 5 to which the dampers are flexibly connected. As shown, the lever is pivoted at 5, the damper 1 is connected to the short arm of the lever by a chain 6, and the damper 2 is connected to the opposite end of the lever by a chain 7. The damper 1 serves as a weight to nearly balance the lever. A rise in pressure within the boiler, above a predetermined amount, will cause the regulating device to rock the lever and close the dampers entirely. lVhen the dampers are in their practically closed positions, as shown, the damper lever is supported by a catch 8 which engages a notch 9, in a rod 10, which is pivotally connected at 11 to the longer arm of the lever and depends therefrom. This catch is automatically locked by a latch 12, which may be disengaged from the catch by a magnet- 13 when the latter is energized. The circuit of the magnet is controlled by a clock mechanism 7), as hereinafter explained, and when the magnet operates to release the catch 8, the rod 10 drops downwardly and the damper lever 5 rocks about its pivotal point 5 and causes both of the dampers to open.

A small electric motor 0 is provided for closing the dampers and this also is controlled by the clock mechanism. As shown, a cord or cable 16 connects the shorter arm of the damper lever with a pulley 17 on the motor shaft, and when the motor is operated it rocks the damper lever into position to practically close the dampers and, at the same time, the rod 10 is lifted until its notch 9 passes over the catch 8 and the latter locks the rod in its upper position.

A motor d is provided for operating a conveyer e which carries fuel from a bin to a chute f, which conducts the fuel to a suitably formed spreader 9 arranged within the furnace. As shown, the motor d is connected by a belt 18 to a large pulley19, at the upper end of the conveyer, and the operation of this pulley causes the conveyer to elevate and deliver the fuel to the chute. The time mechanism controls the motor (Z so as to cause the conveyer to feed fuel at suitable intervals, and a mechanism It, operated by the motor d, stops the latter when a predetermined amount of fuel has been fed, as hereinafter explained.

The timing mechanism comprises a time clock having a hand 20, which turns about the dial 21 once in twenty-four hours, and adjustable hands 22 and 23, which turn about the dial hourly. The hand 20 is adapted to engage a pivoted contact 24; the hand 22 is adapted to engage a pivoted contact 25 and the hand 23 is adapted to engage a pivoted contact 26. A wire 27 connects the clock hands with a transformer t, which latter is connected to wires L and L, leading from a suitable current source. The transformer reduces the voltage to a low value, as 10-12 volts.

A conductor 28 leads from the transformer through the windings of the motor 0 and thence to the pivoted contact arm 24. When the hand 20 engages said arm, it closes the motor circuit and the motor operates to rock the damper lever to close the dampers. This is a small series wound motor which stalls when the dampers are closed. The current is out off from the motor when the hand 20 passes beyond the contact member 24. When the lever is rocked by the motor, the catch 8 supports the rod 10 and the lever after the motor circuit has been opened.

A conductor 29 leads from the transformer to the coil of the tripping magnet 13, and a conductor 30 leads from said magnet to contact 25 of the timing mechanism. When the hand 22 engages said contact, the circuit of the magnet will be completed through conductor 27 to the transformer, and the magnet will be energized. When the magnet is energized it rocks the latch 12, releasing the catch 8, and the rod 10 then rocks the damper rod which moves the dampers to open position.

A conductor 31 leads from the transformer through the coil of magnet 32 of a relay switch is, and thence by conductor 32 to pivoted contact member 26. When the clock hand 23 engages said contact, a circuit is closed through the magnet and the latter rocks a switch arm 33 to closed position. This relay switch makes up the circuit to the motor at through the main switch m. This circuit extends from the supply wire L, through conductor 34 to the motor, thence by conductor 35 to the relay switch, thence by conductor 36 to the main switch, thence by conductor 37 to the supply wire L. When the relay switch and the main switch are both closed, the motor d will operate the conveyer,

but when either switch is opened the motor will be stopped. The hand 23 of the clock will engage the contact member 26 once during each revolution of the hand, and the duration of this contact may be varied by adjusting the contact 26 toward or from the arbor which carries the clock hands. For this purpose, the contact 26, which consists of a centrally pivoted lever, is mounted upon a metal strip 38 which is slidable toward and from the clock. One end of the strip is pivoted at 39 to the central part of a pointer 40, which latter is pivoted at 41 to the clock casing 42. The strip 38 has a longitudinal slot 43, and a stud 44, secured to the clock base, projects through this slot and is provided with a clamping nut 45, by means of which the strip 38 may be clamped to the clock base or frame in any position of adjustment. The contact lever 26 has a Weight 26 at one end, and the strip 38 has an overturned end 38* which projects over the contact member and forms a stop. The weight normally holds the contact member against this stop. The free end of the pointer extends close to an arcuate scale 46. By moving the pointer to the left, the contact member 26 will be engaged by the hand 23 for longerperiods than if the contact member is moved to the right of the position shown in the drawing. The scale 46 will indicate the number of minutes during which the contact is maintained. It will be evident that if the pointer is adjusted to the mark indicating 12 minutes, for instance, on the scale, when the hand 23 engages the contact 26 the motor (Z will be started and the conveyer will operate for twelve minutes, providing the main switch m is closed at the time of this contact. If the main switch is not closed, the conveyer will not be operated. The rod 10, which depends from the damper lever, carries a pawl 10 which passes the lever 47 on the main switch, without operating the switch, when the rod is moved up wardly, butwhen the damper lever is rocked to open the dampers and the rod 10 descends, the pawl will engage the switch lever and move the same downward to close the switch. Below the pawl 10 is a tappet 48, secured to the rod 10, and so formed that if the switch lever is in the on position, this tappet will engage it and move it to the off position when the rod 10 is moved a considerable distance upward, which occurs when the steam pressure rises abnormally and the damper regulator 4 lifts the damper lever. After this tappet has moved the switch lever to the off position, it will also move it to the on position, when the pressure lowers and the rod descends. If, however, the switch lever is in the off position shown in the drawing, when the rod is raised by abnormal steam pressure, the tappet 48 will not move the switch lever to the on position when the pressure lowers and the rod 10 descends.

The feed mechanism It is also adapted to operate the switch arm 47 of the main switch to move the same from the on to the off position after the conveyer has operated a predetermined number of times and has delivered a predetermined amount of fuel into the furnace. This feed mechanism comprises a fine-toothed ratchet wheel 49, which may be turned by a ratchet lever 50, having a pawl 51, which engages these teeth, and the ratchet lever is connected by a ling 52 with a crank 53, secured to the shaft on which the driving pulley 19 is mounted. While the motor is driving the conveyer it will be evident that the ratchet wheel will be moved along by small steps. A pin 54, adjustably mounted on the ratchet Wheel, is adapted to engage a tripping lever 55, which projects into the path of movement of the pm. This lever is centrally pivoted and a spring 56 holds one end of the lever against a stop 57. A pawl 58 projects beyond the opposite end of the tripping lever and over one end of a centrally pivoted lever 59. This end of the latter lever normally rests against a stop 60 and the opposite end of the lever is connected by a cable 61 to the arm 47 of the switch m. The cable is shown passed over a pulley 62. The arrangement is such that as the ratchet wheel 49 rotates in the direction of the arrow, the pin 54 rocks the tripping lever 55 against the action of the spring 56 and the pawl 58 passes the adjacent end of the lever 59 and projects behind it. When the pin 54 passes the tripping lever the latter is brought back into the position shown in the drawing by the spring 56, and the pawl 58 rocks the lever 59 in the direction to throw the switch arm 47 to the off position.

The operation of the mechanism described isas follows: If it is desired, for example, to have the furnace in active operation from say--5 a. m. until 11 p. m. and to then cut oil the draft and bank the fire, the hand 22 will be set to engage the contact 25 at 5 a. m. and the hand 23 will be set to engage the contact 26 a little later, say at 5.20. The hand 20 will be set to engage the contact 24 at 11 p. 1n. When the hand 22 engages the contact 25, the circuit of the tripping magnet 13, heretofore traced, will be energized and this will cause the release of the rod 10 and the draft lever 5 will rock by its own weight and the weight of the rod, to open the dampers 1 and 2. During this operation, the motor 0 is dead and its armature will not resist the movement of the damper lever. As the rod 10 descends, the pawl 1O thereon moves the handle of the main switch m downward to the on position but this does not cause the operation of the motor d because its circuit is open at the relay switch 70.

The hand 23, in twenty minutes after the dampers are opened, engages the contact 26 and remains in engagement with said contact for a time WhlCh is determined by the setting of the pointer 40. When this contact is made, the magnet of the relay switch is is energized and said switch closes, completing the circuit of the motor (I through the main switch which latter was closed when the dampers were opened. The motor d now operates the feeding mechanism and the conveyer feeds fuel into the furnace as long as the hand 23 is in engagementwith the contact member 26. \Vhen the hand passes out of engagement with said member, the circuit through the relay magnet is broken and the relay switch opens the circuit of the motor (I and the latter stops. As the hand 23 turns once an hour, the circuit of the motor d will be closed every hour and fuel will be fed into the furnace every hour for a predetermined time, up to the time assumed, 11 p. m., for closing the draft and banking the fire. At this time, the hand 20, which rotates once in twenty four hours, engages the contact 24 and completes the circuit of the dampercontrolling motor 0. This motor then rocks the damper lever 5 into the position shown in the drawing, wherein the dampers are nearly, although not quite, closed.

It is desirable to feed more fuel 1nto the furnace after the dampers have been closed, to hold the fire until the following morning, and therefore the pin 54 on the fuelfeeding mechanism Will be set so that it will not throw the switch m to the off position until an hour or two after the the dampers have been closed. During this time, the hand 23 will engage the contact 26 hourly and the feeding mechanism will deliver fuel into the furnace while the contact is made. The draft having been closed and sufficient fuel having been fed into the furnace to maintain the fire until the following morning, the pin 54 on the ratchet wheel engages the tripping lever 55 and causes the switch arm of the switch m to be thrown to the off position, thereby stopping the motor (Z and preventing further feeding of fuel. If the clock hands are left in their set positions, the operations will be repeated, commencing at the same time on the following morning. If, at any time, the boiler pressure should rise above a predetermined amount, the diaphragm 4 will raise the damper lever higher than it would be raised by the motor 0 and this will cause both dampers to be closed tightly, and also cause the tappet 48 to throw the arm of the main switch to the off position, if the latter happens to be in the on position. The tappet will return this switch arm to the on position when the pressure lowers.

As the conveyor when in operation delivers a certain amount of fuel per minute, the scale 46 may be indexed either in figures representing pounds of fuel, or minutes.

What I claim is:

1. Mechanism for feeding fuel to furnaces comprising a conveyor, an electric motor for the operation of the motor for predetermined periods at predetermined intervals, and means actuated by the motor for preventing further operations of the motor after it has operated for a predetermined number of periods, said means including a switch in the motor circuit and tripping mechanism driven by the motor and adapted to open said switch when the conveyer has traveled a given distance.

2. Mechanism for controlling the draft and fuel feed of furnaces comprising means for moving the damper of the furnace to open position, a conveyer for feeding fuel to y the furnace, a motor for operating said conveyer, a circuit for the motor including a main switch and relay switch, said main switch adapted to be closed by said damperopening means, and time-controlled means for closing the relay switch at intervals.

\ 3. Mechanism for controlling the draft and fuel feed of furnaces comprising means for moving the damper of the furnace to open position, a conveyer for feeding fuel to the furnace, a motor for operating said conveyer, a circuit for the motor including a main switch and relay switch, said main switch adapted to be closed by said damper-opening means, and means for closing the relay switch 7 periodically for predetermined periods of time.

4. Mechanism for controlling the draft and fuel feed of furnaces comprising means for moving the damper of the furnace to open position, a conveyer for feeding fuel to the furnace, a motor for operating said conveyer, a circuit for the motor including a main switch and relay switch, said main switch adapted to be closed by said damperopening means, means for closing the relay switch periodically for predetermined periods of time, and means for varying the length of such periods.

5. Mechanism for controlling the draft and fuel feed of furnaces comprising means for moving the damper of the furnace to open position, a conveyer for feeding fuel to the furnace, a motor for operating said conveyer, a circuit for the motor including a main switch and relayswitch, said main switch adapted to be closed by said damperopening means, time-controlled means for closing the relay switch at intervals, and means operated by the motor for opening the main switch after the motor has operated a predetermined number of times.

6. Mechanism for feeding fuel to furnaces comprising a conveyer, an electric motor for operating theconveyer, time mechanism and circuits controlled thereby adapted to cause the operation of the motor for predetermined periods at predetermined intervals, and

means for varying the length of such periods.

and a relay switch, means for automatically closing the main switch when the furnace dampers are opened, means for closing the relay switch periodically comprising a timeoperated contact member and a pivotally mounted contact member adapted to be engaged thereby, and means for varying and indicating the duration of the engagement of said members com rising a slide upon which said ivoted mem er is mounted, a pointer mova le with the slide and a scale adjacent the pointer.

In'testimony whereof I hereunto afiix my signature.

ROY H. STULL.

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