US2358828A - Electromagnetic operator - Google Patents

Description

Sept. 26, 1944.

w. A. RAY 2,358,828

ELECTROMAGNETIC OPERATOR Filed Aug. 27, 1942 3nventor:

W/M/AM A. IQA Y,

Patented Sept. 26, 1944 UNITED STATES PATENT OFFICE ELECTROMAGNETIC OPERATOR William A. Bay, Los Angeles, Calif.

Application August 27, 1942, Serial No. 458,358

3 Claims.

My present invention relates to electromagnetic operators, and in particular to those of the so-called weak-current type which are adapted to be operatively energized by a minute amount of power, such as that. available-from a thermoelectric generating device heated by an ordinary small pilot-bumer flame. The magnitude of such power is of the order of ten milliwatts, and has generally been considered as insuiflcient to operate a control device, such as of the invention reference may be had to the following detailed description and accompanying drawing, wherein:

Figure 1 is a view, in longitudinal section, of an electromagnetically operated fluid control valve embodying my invention;

Figures 2 and 3 are transverse sections taken along the lines 2-! and 3-4, respectively, of

an ordinary gas valve, without the aid of supplemental means and energy-as, a motor operated by the energy derived from the fluid controlled by the valve.

It is therefore a main object of .this invention to provide a weak-current electromagnetic device which is capable of operating directly (i. e., without the requirement for supplemental means or energy), for example, a gas valve of suflicient capacity to control the heating of a small residence.

Another obiect of this invention is the provision ofan electromagnetically operated valve, having a capacity suillcient to supply the demand of a domestic gas heating device, which can be operatively energized by a pilot-burnerheated thermoelectric generating device, so that it is independent of the electric service lines and is relatively noiseless in operation.

Another object is the provision of an electromagnet having a pole face, the area of which is considerably greater than that of the cross-sectional area oi the body of its core, so thatwhen the flux density in the core, produced by a weak magnetizing force, is at a point considerably below the knee of the magnetization curve for the core material-the flux density in the large-area pole face is substantially the. same as that which could be produced by the weak magnetizing force if the cross-sectional area of the body of the core were not reduced. An allied object is the provision of an electromagnet, for energization by weak current and of the general character described, wherein the cross-sectional area of the body of the core is small, so that the mean turn-diameter of a coil'wound around it is small and the electrical resistance of the coil correspondingly small. 7

Another object is the provision of anelectromagnetic operator, comprising a U-shaped core having enlarged pole faces, wherein the parts are so arranged that leakage flux is minimized. Other objects and advantages of the invention will be found in the description, the drawing, and in the claims; and ior complete understanding pressure of: the 1 Fig. 1;

Figure 4 is an enlarged fragmentary section taken'along the line 4-4 of Fig. 3; and

Figure 5 is a schematic view, in perspective, of the magnetic circuit of the device shown in the other flgures; and a diagram of a suitable coil-energizing circult.

In the drawing, the numeral ll, indicates a valve casing having an inlet l2 and'an outlet II separated by a partition l4. Threaded in an opening through the horizontal portion of this partition is a valveport member IS, in the top surface of which there is an annular recess it. The side walls of the recess terminate at the surface in a plane to form an inner and an outer valve seat I1 and il, respectively (Fig. 4), the adjacent surface of the port member being relieved so that the seats are generally knifeedged. The recess i8 is fluidly connected with the valve outlet ll by a plurality of openings l8. Cooperable with the valve seats is a disk-like closure 28, preferably of non-magnetic material, which is centrally apertured and has a plurality -of transverse openings 2i (Fig. 4) whereby the inlet fluid can communicate with the area ad- Jacent the inner valve seat l'l. When the maximum lift of the closure is very. small (as in the arrangement shown), increase of flow capacity of the valve is effected by the double valve seat arrangement, since the fluid can pass to the recess in substantially equal amounts across both of the seats. This feature is the subject of Patent No. 2,281,562, granted to meNovember 4. 1941.

Secured by screws to the top surface of the closure III is a disk-shaped armature 22; 9. diaphragm 23, of flexible material such as artificial rubber, being interposed therebetween. This diaphragm serves as a guide for the armatureclosure member, and is secured at its margin between the apertured top wall of the valve casing and a structure 24 mounted thereon.

Supported by the structure 24 is an electromagnet comprising a U-shaped core 2!, formed of round material, to the end of each of the side arms of which is attached a generally semicircular pole plate I! (Fig. 2). The extremities of the core are tapered to fit in correspondingly tapered holes in the pole plates, the material of the plates around these holes being punched- 'up to provide relatively large contact area, and

the ends of the tapered portions of the core are riveted-over to maintain intimate engagement between them and the plates. Extending from the outer edge of each of the poleplates is a plurality of bent-up cars 21 whereby the core and pole-plate assembly is securedv (as by rivets a plane immediately below the underside or pole faces of the plates 28, is a thin disk or diaphragm 3!, of non-magnetic material, which serves both to shield the electromagnet from the fluid controlled by the valve and also as means for preventing direct contact of the armature 22 with the pole faces. The frame 29 has a strengthening cross rib 32 (of non-magnetic metal) which extends closely between the adjacent edges of the pole plates 26 and thus fills the air gap" therebetween, the bottom surface of the rib being in the plane of the pole faces. Around the side arms of the core is a pair of interconnected coil windings 83; and covering the electromagnet is a housing 34, preferably of non-magnetic metal.

Communication between the inlet of the valve and the space above the armature 221s provided by the transverse passages 2! through the closure 7 20, and by a central opening through the armature. The fluid pressure above and below the armature is thus equalized: and any dirt carried by the controlled fluid is prevented, by a filter 36 covering the lower end of the opening 35, from reaching the shallow space between the armature and the pole-face diaphragmv 3i.

When the electromagnet is energized by passage of current through the coil windings 33, the armature- closure member 22, 20 is attracted toward the faces of the pole plates 28, thus opening the valve; a plurality of small bosses 31' (Fig. 4), projecting integrally from the armature, serving to maintain the major portion of the top surface of the armature spaced by a short distance from the diaphragm 31,. For ensuring release of the armature from the electromagnet when the same is-deenergized, a plurality of spring-pressed pins 38 (Fig. 4) is provided, thesepins extending through openings in the armature and having shoulder portions which'engage the underside of the armature so that the tops of the pins are maintained out of engagement with the dia-' for said electromagnet comprising an apertured phragm 3| when the armature is in unattracted I position; initial attractive movement of the armature 'thus being unimpeded.

In Fig. 5, the relation between the size of the core body 25' and of the pole plates 26' is clearly brought out; as illustrated, the ratio of area ofeach of the pole faces to the cross-sectional'are'a (2); its respective core arm being approximately :1. connected, in series with a switch or thermostat 39, for energization by an ordinary thermoelectric generating device M, which is assumed to be of such size that it can be properly heated by the flame of an ordinary .pilot burner and is capable of producing power .of the order of ten The electromagnet is shown in this fl'gure milliwatts. Material of high permeability, such as high-nickel iron" alloy, is preferably employed for the construction of the electromagnet and the armature 22'. vWhen, as was pointed out in the objects, the flux density in the core is at a point considerably below the knee of the magnetization curve for this material, the flux density in the large-area pole faces is substantially the same as could be produced by this weak magnetizing force if the cross-sectional area of the core were the same as that of the pole face. However, by reducing the diameter of the core arms and by making them relatively long, the mean turn diameter of the coil winding maybe small and its electrical resistance correspondingly small. The minute amount of energy generated by the thermoelectric device is thus eflec tive to produce a flux density in the core which, as it appears at the enlarged pole faces, .produces an attractive force on the armature which is considerably greater than could be produced in an electromagnet of conventional form.

While I have herein shown and described a specific embodiment of my invention, I wish it to be understood that modifications may be made without departing from the spirit of the invention, and that I intend therefore to be limited only by the scope of,the appended claims.

I claim as my invention:

1. In an electromagnet: a U-shaped core having at the end of each of its side arms a plate defining a pole face the area of which is at least several times greater than the cross-sectional area of its respective side arm, a coil winding around at least one of the arms of the core, said pole faces being in a plane and'spaced apart to provide an air gap therebetween, and a support claim 1, wherein said supporting member-is pro-- vided with a non-magnetic cross-rib extending through said air gap between the pole plates and in engagement with the adjacent edges of said plates.

3. In an electromagnetic operator: an electromagnet comprising 'a core having an end portion defining a plane .pole face, means for supporting said electromagnet comprising a first ap-- ertured member surrounding said end portion of the core and having a plane outer surface located in the plane of said pole face, a flat second mem-.

her having an aperture corresponding substantially to that of said first member; means for securing said members together, a thin flat nonmagnetic diaphragm interposed between said members and covering said pole face, a disk-like armature substantiallycoextensive with said pole face and positioned closely adjacent. thereto, and

means for supporting and guiding said armature comprising a flexible diaphragm secured thereto and to the outer plane surface of said second member, said diaphragms and said armature defining with the interior of said second member a shallow chamber,

WILLIAM A. RAY.

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