US2122930A - Mechanical control means for liquid fuel burners - Google Patents

Description

July 5, 1938. 2,122,930

MECHANICAL CONTROL MEANS FOR LIQUID FUELIBURNERS A. CURIONI Filed June 29,, 1935 2 Sheets-Sheet 1 Fig.1

ATTORNEY July 5, 1938. A. CURIONI 2,122,930

MECHANICAL CONTROL MEANS FOR LIQUID FUEL BURNERS Filed June 29, 1955 2 sheets-sheet 2 INVENTOR A1. 00 Cue/0N1 ATTORNEY Patented July 5, 1938 UNITED STATES PATENT OFFICE Aldo Curioni, Katonah, N. Y., assignor to The Gasolaire Corporation, poration of New York New York, N. Y., a cor- Application June 29, 1935, Serial No. 29,126

1 Claim.

This invention relates to devices for controlling electric circuits and more particularly refers to improvements in control devices for liquid fuel burners of the type in which electric means are used for igniting the fuel when the operation of the burner is started.

As an example of one type of burner in connection with which the improvements forming the subject of the present invention may be used, reference may be had to an oil burner, such as described and claimed in my copending application, entitled Oil gasifier and burner, Serial No. 715,335, in which a mixture of air and atomized fuel is directed under pressure against a hot impact plate in a vaporizing chamber so as to issue therefrom in the form of a combustible gas.

In said burner the impact plate is initially heated by means of an electric resistance element, which is rendered incandescent by the passage of an electric current and which is arranged so as to function both as a preheater of the impact plate and as an igniter of the air-fuel mixture. An electric motor is used for driving a splash wheel, which directs a spray of atomized fuel against the impact plate, and an air pump, which supplies air under pressure to the vaporizing chamber.

In the operation of a burner of the type specified, or in fact of a burner of the general type used for house heating purposes, it is desirable to delay the admission of fuel to the vaporizing chamber until the igniting element is ready to function, and if used also as a preheating element for the impact member, until the impact member has been heated to a temperature sufficient to vaporize the fuel. It is also desirable to deenergize the igniting element after the ignition of the fuel has taken place, without, however, discontinuing the operation of the motor actuating the fuel and air supplying means.

In control systems heretofore known the required sequence of operation of the various elements mentioned has usually been obtained through the utilization of the thermic or magnetic eifects of an electric current. Thus, switches controlling the various circuits have been caused to operate by the energization or deenergization of solenoids, by relays controlled by thermostatic devices, or by some mechanical action due to the expansion of a metallic member or coil under the influence of heat. In some cases, delay producing devices, such as a dashpot, for instance, have been used in order to delay the closing or opening of a circuit; in other cases a delay has been produced by the gradual operation of a tiltable mercury switch.

All of these controlling devices more or less entail complications in the control circuit and generally result in rather expensive installations, comprising a number of different elements, frequently apt to get out of order or to require constant attention.

The primary object of the present invention is to provide a novel and improved arrangement for controlling the operation of the electric elements of a liquid fuel burner, whereby the various circuits are controlled in the proper sequence by means of an entirely mechanical character.

Another object of the invention is to provide a novel and. improved type of multiple circuit controlling switch whereby a plurality of circuits can be controlled in a predetermined sequence through the operation of a single actuating member.

A further object is to provide a multiple circuit time delay switch of a simple and sturdy construction, comprising a minimum number of parts and adapted for positive and reliable operation of the various circuits in a predetermined sequence.

Other objects and advantages of the present invention will more fully appear as the description proceeds and will be set forth and. claimed in the appended claim.

My invention is illustrated by way of example in the accompanying drawings, in which:

Fig. l is a vertical section of a multiple circuit controlling switch, adapted for use in connection with a liquid fuel burner of the character above specified;

Fig. 2 is a plan sectional view of the same through line 2-2 of Fig. 1;

Fig. 3 is a detail plan sectional View through line 3-3 of Fig. l; and 0 Fig. 4 is a diagrammatic representation of an oil burner and an electric circuit, comprising the electrically operated elements of said burner and the multiple control switch shown in Figs. 1 to 3.

Referring to the diagram of Fig. 4, l0 designates the body of a burner of the type described and claimed in my copending application above referred to, said body forming a quasi circular chamber H at the bottom of which a supply of liquid fuel, I2, is maintained at a constant predetermined level, and an extension from said chamber in the form of a tubular arm l3, terminating in a vaporizing chamber (not shown) within which is located a tubular impact member I4.

Said impact member is initially brought to a high temperature, sufficient for vaporizing the fuel, by an electric resistance element l5, housed therein. An electric motor |6 actuates a splash wheel l1, housed within chamber H and having its lower edge portion immersed within the liquid fuel |2. By virtue of this arrangement, the splash wheel during its rotation picks up fuel from the bottom of chamber and projects it in atomized form within tubular extension |3 against the impact member 14.

By means of a special arrangement (not shown) when the atomized fuel, mixed with air, strikes the hot surface of impact member M and becomes vaporized, part of the resulting gaseous fuel is caused to come in contact with the surface of the incandescent electric element l5, which after having functioned as a preheater for the impact member, will now act as an igniter for the fuel.

As stated before, in the operation of this type of burner it is desirable first to energize the resistance element l5 so as to bring the impact member M to a fuel vaporizing temperature and then to start the motor, in order to supply fuel and air to the vaporizing chamber. The airfuel mixture having become ignited by contact with the electric resistance element, the latter being no longer needed, should then be deenergized while the electric motor continues to operate.

In order to automatically control the energization and deenergization of the various circuits involved in the proper sequence, without resorting to the use of devices depending for their operation upon magnetic or thermic effects of the electric current employed, I have devised an entirely new type of switch whereby all the cirouit connections are controlled by purely mechanical action, the various switches being operated by a single control mechanism.

In the diagram of Fig. 4, H3 designates one of the main wires from an electric source of supply, leading to one of the contact members I9 of a knife switch 20, 2| designates the other main wire, a branch of which, 22, leads to one of the poles 23 of the electric motor l6 and another branch 24 leads to resistance element l5. The other pole 25 of the electric motor is connected by a wire 26 to a contact member 21 of a knife switch 28, and the return wire 29 from the resistance element I5 is connected to a contact member 30 of a knife switch 3|. The other contact member 32 of switch 28 is connected to the other contact member 33 of switch 20 by a bar 34 and a wire 35 connects said bar 34 to the other contact member 36 of switch 3|. Connection between the contact members of switch 20 can be established by insertion therebetween of knife blade 31 and in a similar manner con nection between the contact members of switch 28 can be established by insertion therebetween of knife blade 38 and connection between the contact members of switch 3| can be effected by insertion therebetween of knife blade 39.

When the burner is inoperative the various switch elements are in the position shown, in which knife blade 39 closes the circuit of switch 3| while switches 20, 28, are open. No current can flow through the circuit because the main circuit is interrupted at the switch 20. In order to start the burner the circuit should first be closed at 20 by inserting knife blade 31 between contact members IS, 33; the current will then flow through wire l8, switch 20, bar 34, wire 35, switch 3|, wire 29, resistance element l5 and back through wire 24 to main wire 2|. This will cause the energization of resistance element |5 which will become incandescent and will raise the temperature of impact member M to the fuel vaporizationpoint. Thislasthavingbeenreached, switch 28 should now be closed by insertion of knife blade 38 between contact members 21, 32. This will complete the circuit of the motor through wires 22, 26, so that liquid fuel will now be projected against the hot impact member l4. After a short period ignition of the fuel will have occurred and resistance element l5 should be deenergized by withdrawal of knife blade 39 from its closed position shown. This will interrupt the circuit of the resistance element but will not affect the circuit of the motor, which will remain closed through switches 20, 28.

In Figs. 1 to 3 I illustrate a switch mechanism adapted to control the circuits just described by entirely mechanical means.

The switch assembly, which is enclosed in a casing 40, includes the switch elements shown in Fig. 4, which are also shown in a larger scale in Fig. 3, and means for actuating the same in the proper sequence.

The switch contact members are carried by an insulating block 4| and the switch blades are preferably mounted so as to operate with a quick make and break action. For instance, knife blade 31 is pivotally mounted at 42 on a bracket 43 inwardly extending from end wall 44 of the casing. On the same pivot is mounted a dog 45, having two angularly spaced finger extensions 45, 41, and a downwardly inclined extension 48, connected by a snap-over spring 49 to the switch blade 31.

In the position shown, finger extension 46 is directly in the path of a pin 59, carried by an arm 5|, mounted on a shaft 52. If said shaft is caused to rotate in a counterclockwise direction, as indicated by the arrow in Fig. 1, pin 50 will after a while press against finger extension 46, swinging dog 45 in a clockwise direction about its pivotal support. This will eventually cause the point of attachment 53 of the snap-over spring 49 to reach and pass beyond the dead point, when said snap-over spring, the tension of which has been in the meantime increased, will be able to suddenly contract, acquiring the position shown in dot and dash lines at 49, and forcing the switch blade to the position shown in dot and dash lines at 31.

This will also cause the dog 45 to acquire the position shown in dot and dash lines at 45', in which its finger extension 41 will have come to occupy the position shown at 41, which is directly in the path of the return movement of arm 5|, which will ultimately have acquired the position shown in dot and dash lines at 5|.

Switch blades 33, 39, are pivotally mounted to operate in substantially the same manner on brackets 54, 55, respectively, which are horizontally spaced a certain distance from bracket 43. Pivots 56, 51, of switch blades 38, 39, are preferably coaxial with pivot 42 of switch blade 31, as shown, although the three switch blade structures are entirely independent of one another.

In order to operate the three switches in the proper sequence, it is, therefore, sufficient to provide shaft 52 with two additional switch actuating arms, 58, 59, extending therefrom, said arms being provided with actuating pins 60, 6|, respectively, and being angularly spaced with respect to each other and arm 5|, so as to determine the proper time delay between the operation of the three switches.

It is to be understood that the movement of rotation of shaft 52 should be relatively slow in order to allow a sufiicient time to elapse between the operation of the first switch, causing the energization of the electric resistance element, and that of the second switch controlling the motor circuit; the movement of rotation of said shaft should, therefore, be controlled by a suitable time delay mechanism, for instance, an escapement mechanism of the conventional type shown.

In the same shaft 52 is urged to rotate in a counterclockwise direction by a tension spring 62, attached to a band 63 wound upon a drum S4, fixed on said shaft. Said shaft also carries an actuating arm 65, which projects frontwardly of the casing through a segmental slot 66. Said arm 65 is equipped with a pawl 61, engaging a ratchet wheel 68, formed integral with or attached to a gear wheel 69, forming part of the escapement mechanism. Said gear Wheel is in its turn in mesh with a pinion in, integral with gear wheel 1|, meshing with a pinion l2, integral with a sprocket wheel 13. The rotation of the sprocket wheel 13 is controlled by the escapement mechanism proper, said escapement mechanism comprising a balance wheel 14, mounted on a shaft 15, to which is secured one end of a hair spring it, the other end of which is secured to some stationary point, as at 11. A pin 18 extends from the balance wheel 14 to engage the teeth of the sprocket wheel 13, completing the escapement mechanism which functions in a well known manner.

It is to be understood that the particular type of time delay device used, in order to slow up the rotation of shaft 52, has no bearing on the present invention since it is obvious that a number of different arrangements may be used for the same purpose. The switch mechanism is normally set in its inoperative position by looking its actuating arm 65 against rotation. For instance, said arm may be provided with a pin 59 adapted to be engaged by a latch 80, urged into its engaging position by a spring BI, and adapted to be released by pressing against a finger 82.

It is obvious that, the switch mechanism being in its inoperative position shown in the drawings, by forcing finger 82 upwardly latch 80 will release arm 65 and shaft 52 will begin to rotate, due to the pull exerted by spring 62. Its movement of rotation will take place slowly, due to the delaying action of the clock mechanism, and the three switches controlling the operation of the burner in the manner described will be operated in the proper sequence.

On the other hand, due to the unidirectional character of the connection between arm 65 and ratchet wheel 68, shaft 52, together with arms 5|, 58, 59, carried thereby, can be quicklyrestored to its normal position, shown in the drawings, by means of its actuating arm 65; latch 68 automatically reengaging pin 19 as soon as the return movement of said shaft and arms has been completed.

It will also be observed that during their return j movement arms 59, 58, 5| will restore the switches to their original status, pins 6|, 60, 50, striking fingers 41 of the dogs 45 forming part of the switches, in the order named.

Although I have shown and described the switch controlling the igniter normally closed, it is, of cour scope of my invention to use two of the movement of the actuating means. other words, the switch arrangement sh ld be such that the operation of the actuating member will first cause the energization of the igniter circuit, then the energization of the motor circuit, and then the deenergization of the igniter circuit.

Although I prefer to use individual actuating arms for the various switches because of the possibility of setting said arms at different angular positions, it is within the scope of my invention to use a single actuating member mounted on shaft 52; said actuating member having suitably spaced means for actuating the various switches in the proper sequence after the required time intervals. It is also within the scope of the invention to reverse the relative positions of the switches and actuating means by placing the switch operating members at different points along the path of travel of a single actuating member.

From the foregoing it will be seen that I provide a thoroughly reliable system of control of a plurality of circuits such as are employed, for instance, in connection with an oil burner; my invention also including a new type of multiple switch control mechanism whereby a single op erating member is caused to control a plurality of circuits in a predetermined manner by purely mechanical means.

It is obvious that the constructional details of my invention-may vary from those shown without departing from the inventive idea. The drawings will, therefore, be understood as being intended for illustrative purposes only and not in a limiting sense.

I accordingly reserve the right to carry my invention into practice in all those ways and manners which may enter, fairly, intothe scope of the appended claim.

I claim:

A device of the class described comprising a normally open two pole main switch, a normally open two pole secondary switch having one of its terminals electrically connected to one of the terminals of said main switch, a normally closed auxiliary switch having one of its terminals also connected to said two connected terminals, said switches being arranged in spaced planes, a shaft disposed transversely of said planes, a spring urging said shaft to rotate in a given direction, releasable means restraining said shaft against rotation, time delay means regulating the speed of rotation of said shaft when released, a plurality of switch actuating arms carried by and spaced along said shaft, said arms being angularly disposed with respect to one another and to said switches, so as to first close said main switch, then close said secondary switch, and then open said auxiliary switch after a predetermined time interval said arms restoring said switches to their original status when said shaft is returned to its original position, and a manually operable arm mounted directly on said shaft, for restoring said shaft to its original position, independently of said time delay means.

ALDO CURIONI.

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