US3186469A

US3186469A - Oil burner control

Info

Publication number: US3186469A
Application number: US245024A
Authority: US
Inventors: William G Younger
Original assignee: KEMP Manufacturing CO Ltd
Current assignee: KEMP Manufacturing CO Ltd
Priority date: 1962-12-17
Filing date: 1962-12-17
Publication date: 1965-06-01
Anticipated expiration: 1982-06-01

Description

June 1, 1965 w. G. YOUNGER OIL BURNER CONTROL 3 Sheets-Sheet 1 Filed Dec. 17. 1962 FIG. 2

S W Y E U 0 N Y R aWm o T TM A NM wi mm w June 1, 1965 w. e. YOUNGER OIL BURNER CONTROL 5 Sheets-Sheet 2 Filed Dec. 1'7, 1962 FIG.4

INVENTOR WILLIAM G. YOU NGER BY- WWM ATTORNEYS 3 Sheets-Sheet 3 Filed Dec. 17, 1962 m hr S N Y U E m N m mm H T m A VU w I IW B United States Patent 3,136,469 OIL BURNER CONTRGL William G. Younger, Guelph, Ontario, Canada, assignor to Kemp Manufacturing Co. Ltd, Guelph, Ontario, Canada Filed Dec. 17, 1962, Ser. No. 245,024 3 Claims. (Cl. 158-28) This invention relates to an ignition system for a low pressure vaporizing type oil burner.

It is customary to control vaporizing type oil burners from a thermostat. The burner has two adjustments on the oil supply valve, one of which is adapted to supply oil at a low fire rate and the other of which is adapted to supply oil on a high fire rate. Associated control means supply combustion air by means of a fan as required.

A disadvantage with this type of firing is that the burner must always be on, at least on the low fire rate. Thus, if such a burner is heating a house in very mild weather, the low fire rate may be supplying more heat than is required with the result that the house will overheat. Devices for turning the burner completely off under these conditions and for re-igniting it again when the house cools to a point where heat should again be supplied are, to my knowledge, not known. This invention relates to a system for automatically igniting a burner of this type and for extinguishing it in the event that the low fire rate of firing is more than enough to keep the house at the desired temperature. The ignition system can also be adapted for manual operation to avoid the usual method of inserting a flame inside the vaporizing burner to ignite it.

It is an object of this invention to provide an ignition electrode for an oil furnace which is normally located out of the combustion zone but which is, by rotation of the longitudinal axis thereof about an axis adjacent to the longitudinal axis thereof, movable into the combustion zone of an oil burner.

Generally speaking, the invention comprises a source of heat such as an electric heater or a small gas pilot flame under the vaporizing surface of the vaporizer of the oil burner that is adapted to vaporize initial oil admitted to the unlit vaporizer. An ignition electrode normally located out of the combustion zone but movable into the combustion zone is also provided. An ignition metering valve control means is provided that responds to thermostat operation (or to manual operation) when the burner is not in operation, for rendering the standard high-low metering valve control means inoperative and taking over control of the metering valve operation for the ignition period. The ignition metering valve control means operates to actuate the ignition electrode into the combustion zone. At the same time, it provides for the flow of a small quantity of ignition oil into the combustion chamber. The source of heat operates to vaporize the oil thus supplied and, as it is vaporized, the ignition electrode ignites it. Upon ignition, combustion air is supplied to support the freshly started oil combustion. The air supply is controlled by a bimetallic element in or adjacent the combustion zone. The bimetallic element also operates after a predetermined time delay to return the control of the burner to the normal controls that operate the usual high-low fire adjustments. At the same time, of course, it takes control away from the ignition metering valve control means.

The invention will be clearly understood after reference to the following detailed specification read in conjunction with the drawings.

In the drawings:

FIGURE 1 is a perspective view of a burner and showing the casing within which the unit is mounted in use.

indicates a vaporizing type oil burner.

3,186,469 Patented June 1, 1965 FIGURE 2 is a perspective view of the burner mounted in a furnace;

FIGURE 3 is a cross-sectional view in elevation showing the unit;

FIGURE 4 is a view along the line 4--4 of FIGURE 3;

FIGURE 5 is a plane view of FIGURE 3;

FIGURE 6 is a wiring diagram showing the oil supply to the burner and the control thereof.

.Referring to the drawings, the numeral 10 generally The burner described is very similar in principle to the one described in United States Patent No. 2,661,797, dated December 8, 1953. It has a vaporizer with a combustion chamber 12 to which oil is supplied through the channel 14 as controlled by flow control valve. In normal usage, the flow control valve has two positions, one adapted to supply oil at a low fire rate and the other adapted to supply oil at a high fire rate. Oil is supplied to the base of the combustion chamber 12 which is normally hot. It becomes vaporized and burns. The products of combustion discharge through the open mouth 16 of the combustion chamber and pass out a chimney, not shown. Air to support combustion is driven by a fan through the opening 18 and then into the combustion chamber through the orificed plate 20. These things are well-known and not referred to in detail in this specification.

In the normal manner of operating such a burner, the high and low fire oil and .air supplies are controlled by a thermostat. When the temperature falls below a predetermined level, the high fire rate of firing results. When the temperature reaches a higher level, the low rate of firing results.

As indicated above, the difficulty with this type of firing is that there is a minimum rate of firing that may, under some conditions, overheat the house. There is no provision for automatically extinguishing the burner and, for automatically bringing it on again, in the event that fire is required. This invention serves that purpose.

According to this invention, a burner in which no fire exists is ignited by means of an electrode 22 and the bridge 28 that serves as a second electrode. The bracket 24 that grips the insulation stem 25 of electrode 22 is pivotally mounted as at 23 on a rigid bracket 26 so that the longitudinal axis of the stem 25 can be rotated about an axis adjacent to the longitudinal axis of the stem 25 to cause the electrode to assume a position, as illustrated in solid lines in FIGURE 4, where the free end thereof is in the combustion chamber and also to assume a dotted line position indicated in FIGURE 5, where the free end thereof is free of the combustion chamber. It will be apparent that the stem 25 may be mounted for rotation about the longitudinal axis thereof. The numeral 28 refers to a stainless steel bridge on the bottom of the vaporizer combustion chamber that is grounded and co-operates with the free end of the electrode 22 as a second electrode to form a spark gap. It also serves to localize the oil vapour of the oil for better mixing. The stem 25 is provided with a contact 21 which overlies the contact 21a carried by the stationary connector 27. The stationary electrode is connected to a transformer by supply wire 31 as will be described later.

A source of heat comprising, in the embodiment of the invention shown, an electric heating element 30 is provided underneath thebase of the vaporizer for the purpose of vaporizing the oil used to ignite the burner.

This will be referred to again later.

Reference will now be made to FIGURE 6. In FIG- URE 6, the standard metering valve for supplying oil to the oil burner is generally referred to by the numeral 40. The metering stem 42 of the valve controls the rate of supply of oil to the vaporizer and it is, in turn, controlled or adjusted by means of the swingable armature 44.

Under normal conditions of operation, there are two positions of the armature 44 which permit the supply of oil through channel 14 at a low fire rate and a high fire rate, as indicated above. These two positions of oper ation are controlled by the electromagnet 46. When the armature 44 is attracted to the energized electromagnet 46, the metering stem supplies oil at the high fire rate of speed. At the same time, the armature 44 makes contact with the switch 52 to control the speed of motor fan 48 and supply air at the high rate of speed to maintain a high rate of combustion in the vaporizer.

When electromagnet 46 becomes de-energized, spring 50 swings the armature 44 in a downward position to depress the metering stem 42 to the low flow position with the result that oil is supplied at the low rate of speed. At the same time, armature 44 breaks contact with the microswitch 52 to operate the fan motor 48 a a low rate of speed to supply lesser amounts of combustion air.

Electromagnet 46 is controlled in its operation by the room thermostat generally indicated by the numeral 58 in the standard manner and not referred to in detail in the specification.

With this invention, provision is made for extinguishing the burner when the low fire rate of flow more than heats the house to the desired degree and for re-igniting it again when necessary. I To extinguish the burner, a thermostat 70 responsive to the achievement of a temperature above which it is not desired to go operates to cut ofi the power supply 72 to the unit as a whole and to maintain the power supply so cut off so long as the temperature is elevated above the *desired amount. This will de-energize a solenoid valve (not shown) that is maintained open by the power supply to permit the flow of oil from the. oil control valve 40 to the burner. With the said solenoid valve in the closed position and de-energized, no oil can be supplied to the burner. When, however, power is again available to the unit as a whole, the solenoid valve automatically opens and oil is permitted to how to the vaporizer from the oil control valve 40 according to its setting.

On the assumption that the vaporizer cools down before heat is again called for, the reignition of the burner is automatically achieved by thermostat operation through the electrode 22 in the following manner. In the first place, thermostat 70 operates to supply power to the unit as a whole and to open the aforementioned solenoid valve in the oil supply line. Power is supplied to a heater associated with a bimetallic strip 54 by the

lines

76 and 78. It will be noted that the

contacts

80 and 82 of a thermostatic control, to be referred to later, are closed'to permit the transfer of power from the power lines to the heater of the bimetallic element 54.

As the bimetallic element 54 heats up, it moves to the dotted line position shown in FIGUREG against the stop 84. As it does so, it operates microswitch 86 from the solid line position to the dotted line position. The effect of this is to disconnect the solenoid 46 from the power supply so that, in effect, the armature 44 is not controlled by the solenoid 46 but is controlled by the bimetallic element 54.

The position of the armature 44 under these conditions is controlled by the head on the bottom of shank 90. When the bimetallic strip is against the stop 84, the head on the free end of shank holds the armature 44 in a position that adjusts the valve 40 between high and low fire positions whereby a quantity of oil is fed to the vaporizer for ignition purposes.

It will be noted that a contact 92 is carried by the free endof shank 90, the free end of which is adapted to engagewith the switch 52 to select a high motor speed for the motor 48. Numerals 96 refer to guides that guide the free end of contact 92 through an orifice in the armature 44 to' permit it to engage with the switch 52 as the contact 92 travels in an upward direction as it follows the bi-;

metallic element 54.

- 4 It should be noted at this point that the engagement of the contact 92 with the switch 52 does not actually operate the motor at a high speed. It merely sets the switch thereof for high speed operation. The motor 48 at this stage has no power supplied to it. Actual operation of the motor during the ignition period at high speed is controlled thermostatically, as will be referred to shortly. At the same time that ignition oil is supplied to the vaporizing chamber, means are provided for actuating the electrode 22 from its inoperative position out of the vaporizing chamber to a position into the vaporizing chamber. As the electrode reaches its operative position, it completes an electrical circuit that energizes the electrode and supplies power to the heater to vaporize the oil. These things will now be referred to.

As the bimetallic element 54 flexes to its upper position,

. the plunger 86a thereof is carried in an upward position to move the contacts of switch 98 to the dotted line position, as referred to above. This energizes the coil 100 of the electrode actuating solenoid. This moves the armature 102 thereof in the direction of the arrow shown in FIGURE 6 to rotate the electrode 22 about point 23 through link 103 within its rotatable mounting from the dotted line position to the solid line position, as shown in FIGURE 5. As the electrode 22 completes its travel into the vaporizing chamber, the armature 102 that controls its movement closes a switch 110 to complete an electrical circuit that supplies power to the heater 30 and potential by means of a transformer 29 to the electrode 22 for igniting vapour at the gap between electrode 22 and bridge 28. The potential is between the free end of the electrode and the bridge 28. Bridge 28 is stainless steel and part of the grounded metal frame of the vaporizer.

Under these conditions, the heater under the vaporizer produces heat to vaporize the oil flowing to the vaporizer to cause the oil to vaporize. 'As it vaporizes, the potential between the electrode 22 and the bridge 28 breaks across the gap and ignites the oil vapoun It has been found that a voltage of about 10,000 volts across a gap of about of an inch ignites the oil vapour very ethciently. A heater of about 1,000 watts has been found satisfactory for heating the oil to vaporize it prior to ignition.

After the oil is ignited, as just described, a bimetallic element 120 located in the vaporizer operates due to the heat of combustion to move the contact 82 thereof from the contact 80, as shown, to engage with the contact 122. This change supplies power to the motor 48 which, by

I reason of the contact 92 engaging with switch 52, is set operation,

to operate at high speed and supply sufiicient air to the combustion to maintain it. The added air of high fire is needed at this stage of operation to assure cleanliness of In some instances, excess oil is introduced during the ignition and an excess of air provided by high speed motor operation insures that there will always be air for the combustion ofit in a clean manner. The change of contact 82 from contact to 122 also serves to cut oif power from the heater element of the bimetallic switch 54, This cut-off of power permits the bimetallic element to cool and to re-assert itself and assume its solid line position, as shown in FIGURE 6. This again and in turn permits' switch 93 to assume its solid line position and put electromagnet 46 again in control of the supply of oil to the burner. It also cuts off the power supply to the solenoid with the result that the plunger 102 thereof assumes its normal position by movement to the right, as viewed. in FIGURE 6, to de-energize the heater and electrode operating circuit. A return spring returns the electrode to its normal position shown in dotted lines in FIGURE 5. The spring is'mounted on the electrode carriage and does not show in the drawmgs.

It will be noted that the electromagnet 46 and the solenoid are each operated on direct current through the rectifier 149, which takes its power from the power transformer 142.

An important feature of the invention is tion in a vaporizing type of burner of ignition electrodes that operates in conjunction with an oil preheater to ignite an oil burner of the vaporizing low pressuretype.

It'might be noted that, after the burner extinguishes,

it cannot be re-ignited until the vaporizer has cooled sufiiciently to avoid the danger of an explosion. This is so i because of the operation of bimetallic switch element 32 that is located in the vaporizer, If the vaporizer is hot, contacts 32 and 80 are open and the ignition system can not energize. r V

Embodiments of the invention other than the one disclosed will be apparent. For example, the electrode system is capable of variation. One might provide that both electrodes be movable in and out of the vaporizer instead of having one ofthe electrodes permanently in the vaporizer in the form of the bridge 28.

What I claim as my invention is: j

1. In an oil'burner of the vaporizing type having means I for supplying oil and air to the vaporizer thereof for combustion at least at one predetermined rate, said'vaporizer having a throat through which burning oil may pass, the improvement of means for igniting the burner comprising a heater for initially vaporizing oil in the vaporizer, a pair of electrodes adapted to operate in the vaporizer of said oil burner, means for applying an electrical potential across said electrodes to ignite oil vapour formed by said heater whereby said burner is ignited, said means for supplying oil for vaporization by said heater and said means for applying electrical potential all being responsive to a signal indicative of a demand for heat from the burner, means for mounting one of said electrodes for movement of the tip end thereof between a normal position and an operative position, said normal the combinaposition being one in which said tip end thereof is out of the combustion zone of said vaporizer, said operative position being one in which said tip end thereof is in the combustion zone of said vaporizer, and having means for moving the movable electrode between said two positions, said movable electrode including a stem and one hooked end, said means for mountingsaid electrode comprising means for mounting said stem'on said vaporizer for retation about a line having the direction of the longitudinal axis of said stem, said longitudinal axis being arranged at an angle to the longitudinal axisof said throat of said vaporizer as it is rotated about its stem to move the tip end thereof between said normal position and said operative position.-

2. An oil burner asclaimed in'claim 1 having means for initiating the supply of forced air to said vaporizer to support combustion of oil vapour after initial ignition by said electrodes.

3. An oil burner as claimed in claim 1, in which one of said electrodes is fixed to said vaporizer.

References Cited by the Examiner UNITED STATES PATENTS JAMES'W, WESTHAVER, Primary Examiner.

Claims

1. IN AN OIL BURNER OF THE VAPORIZED TYPE HAVING MEANS FOR SUPPLYING OIL AND AIR TO THE VAPORIZER THEREOF FOR COMBUSTION AT LEAST ONE PREDETERMINED RATE, SAID VAPORIZER HAVING A THROAT THROUGH WHICH BURNING OIL MAY PASS, THE IMPROVEMENT OF MEANS FOR IGNITING THE BURNER COMPRISING A HEATER OF MEANS FOR IGNITING THE BURNER VAPORIZER, A PAIR OF ELECTRODES ADAPTED TO OPERATE IN THE VAPORIZER OF SAID OIL BURNER, MEANS FOR APPLYING AN ELECTRICAL POTENTIAL ACROSS SAID ELECTRODES TO IGNITE OIL VAPOR FORMED BY SAID HEATER WHEREBY SAID BURNER IS IGNITED, SAID MEANS FOR SUPPLYING OIL FOR VAPORIZATION BY SAID HEATER AND SAID MEANS FOR APPLYING ELECTRICAL POPTENTIAL ALL BEING RESPONSIVE TO A SIGNAL INDICTIVE OF A DEMAND FOR HEAT FROM THE BURNER, MEANS FOR MOUNTING ONE OF SAID ELECTRODES FOR MOVEMENT OF THE TIP END THEREOF BETWEEN A NORMAL POSITION AND AN OPERATIVE POSITION, SAID NORMAL POSITION BEING ONE IN WHICH SAID TIP END THEREOF IS OUT OF THE COMBUSTION ZONE OF SAID VAPORIZER, SAID OPERATIVE POSITION BEING ONE IN WHICH SAID TIP END THEREOF IS IN THE COMBUSTION ZONE OF SAID VAPORIZER, AND HAVING MEANS FOR MOVING THE MOVABLE ELECTRODE BETWEEN SAID TWO POSITIONS, SAID MOVABLE ELECTRODE INCLUDING A STEM AND ONE HOOKED END, SAID MEANS FOR MOUNTING SAID ELECTRODE COMPRISING MEANS FOR MOUNTING SAID STEM ON SAID VAPORIZER FOR ROTATION ABOUT A LINE HAVING THE DIRECTION OF THE LONGITUDINAL AXIS OF SAID STEM, SAID LONFITUDINAL AXIS BEING ARRANGED AT AN ANGLE TO THE LONGITUDINAL AXIS OF SAID THROAT OF SAID VAPORIZER AS IT IS ROTATED ABOUT ITS STEM TO MOVE THE TIP END THEREOF BETWEEN SAID NORMAL POSITION AND SAID OPERATIVE POSITION.