US2722270A - Spark responsive safety starting control for oil burners - Google Patents

Description

Nov. 1, 1955 L BONGIORNO SPARK RESPONSIVE SAFETY STARTING CONTROL FOR OIL BURNERS Filed Dec. 13, 1954 w if m d Mw W E H VW WWQAW i s United States Patent O SPARK RESPONSIVE SAFETY STARTING CONTROL FOR OIL BURNERS Leonard Bongiorno, Brooklyn, N. Y., assignor to Leonard Bongiorno, Minnie Rosen, Julius Rosen, Eli Ellner, and Albert J. Bongiorno, all of Brooklyn, N. Y., a mutual partnership Application December 13, 1954, Serial No. 474,653 3 Claims. (Cl. 158-28) The invention herein disclosed relates to mechanism for starting oil burners.

In starting systems at present in use the oil is sprayed into the combustion chamber for a period of forty-five to ninety seconds, regardless of whether it is ignited. On defective or delayed ignition this occasions a usually mild but sometimes violent explosion or puf-back- An important object of the present invention is to eliminate this initial spray of non-ignited oil and to control matters so that no oil will be supplied until the spark or ignition activating medium is present.

Other important objects are to provide this safety control in a simple, practical, efficient form readily applicable to existing burner systems, which can be produced and installed at low cost and which can be relied on to continue in service without requiring special attention.

These and other desirable objects are attained through a special novel combination of parts as hereinafter described in detail and illustrated by way of example in the accompanying drawing.

In this drawing there is illustrated a practical commercial embodiment of the invention but it will be appreciated that structure may be modified and changed, all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Fig. l in the drawing is a fragmentary and diagrammatic view showing how the invention may be made up as a single control unit which can be used to replace one of the electrodes now presently in use and be connected in with other more or less standard parts of a conventional burner system;

Fig. 2 is an enlarged broken sectional view of the new control electrode.

. In the illustration a burner nozzle is indicated at 5, and electrodes for effecting ignition atv 6 and 7.

The first of these electrodes is shown as of conventional design, carried by an elongated insulator 8 of porcelain or the like equipped with an outer terminal 9 connected by high tension lead 10 with one output terminal of transformer 11.

The other electrode 7 is of special construction, being tubular in form to provide a chamber 12 at the end containing air or other expansible medium.

This hollow electrode is shown connected into the end of a cylinder 13 containing a free piston 14. This piston is indicated as sealed and lubricated within the cylinder by a filling of light grease 15 which may extend well up into the electrode, as shown.

The cylinder 13 and sliding piston 14 may be of glass and the sealing and lubricating agent may be a light grease of zero grade.

A switch operating rod or stem 16 is shown extending from the piston through a guide opening 17 in the end wall 18 of a stationary sleeve or cup 19.

This rod is electrically connected with the sleeve 19 in the illustration by a light, flexible wire 20 extending from the sleeve to the rod, and the rod carries at its free end, within the sleeve, a contact head 21 engageable with 2,722,270 Patented Nov. 1, 1955 a companion Contact 22 seated by insulation 23 in the outer end of the sleeve.

The parts 21, 22 are thus made to constitute the opposing contacts of a switch operable from the piston subject to pressure of air or other expansible medium in the hollow electrode.

Wires 24, 25 are shown extending from these switch contacts to the terminals of a pressure switch 26.

The hollow electrode, pressure cylinder and switch mechanism are all shown contained within an insulating casing 27 of porcelain or other suitable material and it is to be noted that this insulating support is preferably of the same size as the insulator of the first electrode so that the two may be interchanged if necessary and so that this new control unit may be substituted in place of an ordinary or more or less standard electrode.

The motor control connections 24, 25 are shown brought out of the back end of the insulator 27, as also the terminal 28 for the high tension connection 29 extending through the insulator to the electrode tube.

The high tension terminal 28 is shown connected by lead 30 with the other terminal of the transformer.

The two electrodes are thus connected in a high tension spark discharge circuit within igniting range of the burner nozzle.

The pressure control switch in the illustration in addition to being connected in shunt across the pressure switch, is directly connected by wires 31 and 32 with the control relay 33 and with one side of the motor 34. The other side of the motor is shown connected by wiring 35 with the appropriate terminal of the relay.

As a consequence the closing of switch 21, 22 will close circuit through motor 34 which drives pump 36 independently of pressure switch 26 and the latter, through pressure connection 37 from the pump, will hold the motor circuit closed independently of control switch 21, 22.

To protect the parts and assure smooth, effective and quickly responsive action, the piston is shown connected with the switch through a slip clutch or slip joint connection taking the form of a head 38 on the end of rod 16 fitting within the piston and having a spring pressed plug 39 in frictional engagement with the inner piston wall.

To avoid any possibility of binding of parts, the piston rod 16 is shown as having a universal ball joint connection 40 with the friction head 38 and the latter is shown as vented at 42 and the stationary contact plate 22 as vented at 43 to prevent trapping of air which might interfere with proper operation of movable parts.

With this construction pressure may build up on the piston after movable contact 21 has been forced over into engagement with fixed contact 22, the piston then sliding in the cylinder over the head 38 which has been stopped by engagement of the switch contacts.

In reverse order, when pressure is reduced the movable contact 21 may engage and be stopped by stationary wall 18 and thereafter the piston may continue to move over the friction head 38, with the piston eventually stopping at a point determined by the contraction of air or other pressure medium in the hollow electrode. In this latter event the piston is left at a point where it will be most susceptible to expanding pressure developed in the hollow electrode.

Temperature of the high tension spark discharge across the electrodes (about l500 F.) is sufficient ordinarily to accomplish practically immediate expansion of the small quantity of air or other gaseous medium confined in the end of the hollow electrode. Consequently action of the control becomes effective as soon as ignition medium or activator is present-in other words, practically as soon as an effective arc is established.

The slip joint between the piston and motor starting switch leaves the piston in the most effective position to close the switch immediately as pressure builds up, so ordinarily there will be no delay in starting the pump motor as soon as a hot ignition spark is provided. Thus the unit is fast and responsive in its operation.

In the illustration a thermostat 41 is shown providing automatic control of the system, but it will be realized that other such control means may be employed.

Operation In the example shown, when the thermostat 41 calls for heat, relay 33 will be actuated to send an ignition discharge from transformer 11 across electrodes 6 and 7. Air or other expansive medium contained within the tip of the hollow electrode 7 will be heated by this high tension discharge and expansion of this medium acting on the grease lling 15 will force piston 14 over to the right causing stem 16 to carry switch Contact 21 into engagement with contact 22, closing energizing circuit 31, 24 and 25, 32 and 35 through the pump motor 34. Pressure developed by the pump 36 acting through pipeline 37 will operate pressure switch 26 to close the energizing circuit through the motor independently of motor starting switch 21, 22 and to hold this motor energizing circuit closed so long as the thermostat requires heat.

After the piston closes the motor starting switch it may continue its motion in further expansion of the actuating iluid, the slip connection 38, 39 permitting this overriding action of the piston, the switch being held closed the more firmly.

The momentary time required for the expansion uid to heat up and close the motor starting switch makes sure that a hot ignition spark discharge will be established before the pump can initiate a spray of fuel at the nozzle. Practically instantaneous ignition of fuel is thereby assured and fuel can only be supplied it adequate ignition discharge is present.

In the intermittent system illustrated the pressure switch 26 energized by fuel pressure from the pump and arranged in shunt relation with the motor control switch closes circuit for the motor practically as soon as ignition is effected and then holds this circuit closed, independently of the control switch, so long as the thermostat requires heat.

With the pump motor kept in operation by the pressure switch, the relay, after the predetermined time for which it is set, will open the transformer circuit. With stoppage of discharge across the electrodes the expansion medium in the hollow electrode will contract, drawing back the piston and opening the motor control switch.

The movable switch element 21 is stopped in this switch opening movement by engagement with the stop wall 1 8 but the piston, by reason of the slip joint 39,A is free to continue its movement in the further contraction of the controlV medium, as indicated in Fig. 1, thus to locate itself at they extreme limit of retractive movement, where i it will be most responsive to expansion of uid on the next ignition discharge.

With a constant spark system the action would be generally the same, the pressure switch in such case, however, being unnecessary and the control switch either directly or possibly through a relay, serving as the motor switch.

To better illustrate the action, the movement of switch parts shown in the drawing has been somewhat exaggerated.

The pressure actuated switch mechanism may be small enough to be incorporated in an insulator 27 of the same size as one of the regular insulators shown at 8, thus making it possible for the invention to be installed in a standard burner system by simply removing one of the usual electrodes and replacing it with the special control electrode disclosed and then simply connecting the latter in on the motor control circuit.

Thus the invention can be very readily incorporated in existing burner systems.

What is claimed is:

1. Safety starting control for oil burners comprising an electrode having a hollow tip portion containing a heat responsive gaseous medium expansible by ignition discharge heat of the electrode, means including a pressure displaceable, slidable piston means at the outer end of said hollow electrode and in pressure transmission connection therewith, a body of light grease lling the outer end of said hollow electrode and extending from the body of heat responsive, expansible gaseous medium in the tip of the electrode into pressure transmitting engagement with said pressure displaceable piston means and forming a continuous plastic seal and pressure transmitting mechanical connection from the expansible gaseous medium in the tip of said electrode to said pressure displaceable piston means, a switch operable by said pressure displaceable piston means, means for controlling supply of fuel to the burner, and operating connections extending from said switch to said last mentioned controlling means.

2. The invention according to claim 1, with a slip drive connection interposed between said slidable piston means and said switch.

3. The invention according to claim l, in which there is a cylinder open to the outer end of the hollow electrode and said slidable piston means includes a piston operating in said cylinder at the end of said hollow electrode, and in which a slip drive connection is provided between said piston and said switch.

References Cited in the tile ofY this patent UNITED STATES PATENTS

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