Electromagnetic operator
United States Patent 2292478

My present invention relates to electromagnetic operators, and particularly to those of the type adapted for the operation of fluid control valves. In a gas burning system employing an intermittently burning main burner and a continuously burning pilot burner, it is desirable to provide electrically...

Ray, William A.
Application Number:
Publication Date:
Filing Date:
Ray, William A.
Primary Class:
Other Classes:
137/66, 137/872, 251/69, 335/281, 361/162, 361/210, 431/59
International Classes:
F23N5/10; F23N1/00
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My present invention relates to electromagnetic operators, and particularly to those of the type adapted for the operation of fluid control valves.

In a gas burning system employing an intermittently burning main burner and a continuously burning pilot burner, it is desirable to provide electrically operated safety means for stopping fuel supply to both of the burners in the event of the extinction of the pilot burner flame. Such safety means may include a thermoelectric generating device heated by the pilot burner flame, or a thermal cut-out responsive to the flame and controlling any suitable source of electric energy. It is therefore an object of my invention to provide a valve having manually openable means for supplying fuel to the pilot burner and electromagnetically retained in open position against a bias, and automatic electromagnetically operated means for controlling fuel supply to the main burner, the automatic means when energized being effective only when the pilot burner control means is in open position.

Another object is the provision of an electromagnetic device which when energized may be rendered operable or inoperable by mechanical movement of its core member. A further object is the provision of electromagnetic means for retaining the core member in either of its controlling positions. Other objects and advantages of my invention will be found in the description, the drawing, and the appended claim.

For complete understanding of the invention, reference may be had to the following detailed description and accompanying drawing, wherein: Figure 1 is a partly diagrammatic view of a. burner control system embodying my invention; Figure 2 is a sectional view of the electromagnetically operated valve shown in Fig. 1; and Figure 3 is a diagrammatic view of the electric and magnetic circuits of the operator shown in Fig. 2.

In Fig. 1 of the drawing, the numeral 9i in-dicates a fluid control valve, shown in detail in 15 Fig. 2, and connected by a conduit 2 to a main burner 13. A pilot burner 14 for the main burner, connected by a pipe 15 to an upper portion of the valve, serves also to heat a thermopile 16 electrically connected to the valve by wires 50s 17. The thermopile is also connected to the valve through a limit control or thermostat IBS.

In Fig. 2, a ported partition 19, separating the inlet and the outlet of a valve casing 20 of nonmagnetic material is provided with an annular valve seat 21 with which a magnetic valve member or armature 22 cooperates. Secured to the valve casing is a cylindrical housing 23 which supports a dished member 24, to the underside of which is secured, as by solder or brazing, an inverted cup-shaped core 25, of magnetic material. Secured in a concentric opening formed in the core 25 is a tube 26, of non-magnetic material, within which a cylindrical inner core 27 is reciprocable. The underside of the enlarged upper portion 28 of the core 21 is adapted to engage the upper surface of core 25, an annular recess 29 being provided as clearance for the riveted-over upper end of tube 26. Within the outer or fixed core 25 is a pair of cylindrical energizing coils 30 and 31 having leads connected to terminals 32, insulatingly mounted in the upper top wall of the housing. The purposes and circuit connections of these coils will be described hereinafter in connection with Fig. 3.

The bottom surfaces of the cores 25 and 27 are accurately machined so as to lie in a single plane when the movable core 27 is in the down position as shown in Fig. 2; in this position the cores when sufficiently energized are effective to attract and lift the armature 22 which is guided by a non-magnetic pin 33, freely slidable in a central bore of the core 27 and downwardly biased by a spring 34. Shims 35, between the engaging surfaces of the dished member 24 and the housing, are provided for vertical adjustment of the cores with respect to the armature.

An actuating or reset rod 36, threaded in the upper end of the movable core 27, freely extends through an opening 31 in the top wall of the housing and is guided at its upper end by a hollow member 38 secured to the top of the housing. A spring 30, compressed between the top of member 38 and a button 40 provided on the end of rod 30, urges the movable core upward. A cap 4i, threaded on member 38, prevents the possibility of escape of fluid from the valve around rod 36.

With the valve parts in the position shown in Fig. 2, fuel can flow from the inlet of the casing through an opening 42 in the dished member 24, through the opening 0: surrounding the reset rod, and through pipe 5 to the pilot burner; flow to the main burner being obstructed by the valve member or armature 22 which is now in engagement with seat 21. An enlarged portion 43 of rod 36 serves as a valve member cooperable with the opening 87 to control fuel flow to the pilot burner.

Referring now to the diagrammatic showing of Fig. 3 wherein the corresponding elements have been given the same reference numerals as in Fig. 2, the electrical operation of the device will be described. It will be noted that coil 30 is directly connected to a source of current, indicated by the legend "Pilot-heated thermocouples," and that coil 31 is in parallel with coil 30 through the thermostat. For the sake of simplicity, in Fig. 3 it is assumed that the pilot burner is continuously supplied with fuel by a pipe connected ahead of the main valve. The parts are here shown in the positions which they assume when the pilot burner is extinguished, the movable core 27 having been moved upward by the force of spring 44, which for the sake of clarity has been shown in this figure as of contractile form. Assuming now that the pilot burner is lighted and that the circuit controlling means of thermostat 18 is open, current will flow in coil 30 only. This coil is arranged to be of relatively high resistance so that the core 25 and 21 are but weakly energized, the armature 22 and the movable core 21 therefore remaining unattracted. If the core 27 is now manually moved downward so that its enlarged portion 28 engages the upper surface of core 25, the core 27 will be magnetically held in this position against the force of spring 44 by the weak flux produced by the current flow in coil 30. With the core 21 thus held in its depressed position (as shown in Fig. 2), the energization of the cores by current flow in coil 30 is insufficient to cause them to attract armature 22, even although the flux is now more closely linked with the armature by the proximity of the lower surface of core 27. If the circuit through the other coil 31 is now completed through the thermostat, the cores will be sufficiently energized to cause them to attract the armature and lift it against its bias into engagement with their bottom surfaces; the coil 31 being of low resistance and thus permitting a relatively large amount of current to flow. If the circuit through coil 31 is now periodically opened and closed by the thermostat, the armature will automatically fall and rise.

If the pilot burner is extinguished, the resultant cessation of current in both coils will permit the armature to fall and the core 27 to be moved upward by its spring out of engagement with core 25, the device remaining inoperative until the pilot burner is relighted and the core 21 again manually moved into engagement with core 25. If, after relighting the pilot burner, the core 27 is left in its elevated position, current flow in the coils 30 and 31 will not effect attraction of the armature on account of the relatively large gap between the armature and the bottom surface of the core 27. The bottom surface area of the fixed core 25 is preferably relatively small (or that core may be constructed of material having relatively low permeability) so that the movable core 27 exerts the major influnce on the armature. The dependent side wall of the fixed core is not essential and under some conditions only the upper portion of this core need be employed.

Obviously, if desired, a separate source of current could be employed for the energization of coil 31. Also, a thermal cut-out responsive to the pilot burner flame and controlling a suitable source of electrical energy could be substituted for the thermopile. If it were desirable, in some application of the device, that the movable core should be magnetically held in elevated, instead of depressed, position, it would only be necessary to change the position of the extension 28 with respect to the movable core so that it could engage the underside of the top wall of the fixed core. The operation of the valve shown in Figs. 1 and 2 should now be apparent. With the parts in the position shown in Fig. 2, fuel is passing to the pilot burner and the thermopile is energizing coil 30 sufficiently to hold the movable core in depressed position. The valve is therefore in condition for automatic operation of the main burner valve in response to the demand of the thermostat. In the event of failure of the pilot burner flame, upon cessation of current the core 21 moves upward, the valve member 43 closing the opening 37. The valve member 22, if it was then in open position, also closes, and fuel supply to both the main and the pilot burner is thus closed. To initiate further. operation of the system, the cap 41 is removed, the button 40 depressed, and the pilot burner relighted.

The button is held in depressed position until the thermopile is sufficiently heated to energize coil 30 to hold the cores in engagement. The valve is then again in condition for automatic operation of its main valve.

If shut-off of the pilot burner is not required upon extinction of its flame, the pilot burner may be separately supplied from the gas conduit Sinstead of through the valve, automatic operation and safety shut-off of the main burner still being effected.

While I have shown the electromagnetic operator of my invention in connection with the conStrol of valve means, it is obviously not so limited, as other means, such as, for example, switching means, could likewise be controlled by it. Further modifications may likewise be made without departing from the spirit of my invention.

I intend therefore that my invention be limited only by the scope of the appended claim.

I claim as my invention: In an electromagnetic operator, a fixed core of inverted cup-shaped form, an elongated core extending through an opening in the top wall of said fixed core and magnetically spaced therefrom, mechanical means for moving said elongated core between a first position wherein the plane of the bottom surface thereof is above that of the mouth of the cup-shaped core and a second position wherein the bottom surfaces of the elongated core and of the cup-shaped core are in substantially the same plane, means biasing said elongated core to said first position, a first and a second energizing coil both entirely within the cup-shaped core and between it and the elongated core, and an armature mounted below said cores and movable toward and away from them, one of said energizing coils being adapted for operation by voltage capable of producing flux in said cores such that said armature can be attracted only when the elongated core is in said second position, said elongated core having an enlarged upper end portion which is engageable with the top surface of the cup-shaped core when the elongated core is in said second position, the other of said energizing coils being adapted for operation by voltage capable of producing in said cores flux in an amount sufficient to cause the elongated core to be magnetically held by its enlarged portion in its second position against the force of said bias but insufficient then to cause attraction of said armature.