US2374416A - Electric regulator pile - Google Patents

Description

April 24, 1945.

A. H. CHILTON ELECTRI C REGULATOR FILE Filed Feb. 15, 1943 2 Sheets-Sheet 1 A. H. CHILTON 2,374,416 ELECTRIC REGULATOR FILE Filed Feb. 15, 1945 2 Sheets-Sheet ,2

v 1/ I l I merits compo-sing the pile.

Patented Apr. 24, 1945 ELECTRIC REGULATOR PILE Alfred Henry Chilton, Deptford, England, assignor to J. Stone & Company Limited, Deptford, England, a company of Great Britain Application February 15, 1943, Serial No. 475,988 In Great Britain January 9, 1942 6 Claims.

This invention comprises improvements in and connected with pile regulators for electric circuits and is particularly concerned with carbon pile regulators such as are employed in lighting and otherinstallations in railway and other'vehicles and aircraft. The object of the invention is to provide for the cooling of a pile in a convenient manner without interfering with the accessibility of the pile for purposes of observation and attention, the cooling enabling the permissible loading of such pile to be appreciably. increased over that of normal iles wherein the cooling depends on natural air current flow over exposed portions of such piles. The carbon piles of automatic regulators working in the installations aforesaid are always carrying current, so that their permissible loading and continuous rating must be such that injurious temperatures are not reached. The important requirement is to pro vide a pile which is readily accessible for observation and attention and in which the permissible loading is as high as possible having regard to the conductive areas or dimensions of the ele- Carbon piles have been insulatedly enclosed in metal and other casings or containers adapted for externally conducting and dissipating heat, generated in such piles. The aforesaid object of the present invention however, is to be achieved by cooling'the pile from the interior and avoiding enclosure of the pile.

According to the present invention, a regulator pile of annular elements is provided with a heat conductive core which is electrically insulated from the pile or makes no electrically conductive contact with the pile elements and which is fitted with externally disposed means adapated for dissipating as by radiation and/or convection, heat conducted by the core from the interior of the pile,

The core is a heat conductive rod, for example a copper rod, and is advantageously enclosed by an insulating tube passing through and supporting the annular carbon discs of the pile. Various auxiliary means may be adopted for improving the heat contact between the tube and rod, instead of, or in addition to relying upon a close lit of the rod within the tube. Thus any space between the rod and tube may be filled wtih heat conductive cement, lead, solder or other suitable material, or the inside of the tube may be metallically coated, as with silver, and then soldered to or otherwise given a close union with, the metal rod. A hollow form of rod may in some cases be preferred to a solid form.

The cooling or radiator fins or discs may be fixed on one end of the rod externally of the frame or base supporting the pile. Or, the rod may be extended beyond both ends of the pile, fins being fitted on one end as aforesaid and also on the other end beyond the presser plate operating on the pile at that end. This latter ar rangeinent is very convenient in regulators wherein a group of two or more piles is operated upon by a single presser plate which can be cut away to permit of the passage of the rods.

With carbon piles having the provisions above described the permissible loading is appreciably increased over that of normal piles where the cooling depends on natural air currents over the outer and inner surface of the rings. The heat normally dissipated from the outside surface is not interfered with, but the amount of heat car-- ried away from the inner surface is increased enormously by conduction through the insulating tube and along the rod to the fins. There is, moreover, the further important advantage that the outside surface of the carbon rings remains visible and available for ready inspection. In the maintenance of carbon pile regulators, it is very important to examine the condition of the carbon rings from time to time. If this is done, any tendency of the carbons to burn or disintegrate with age will be detected in good time so that the rings can lie-replaced before failure occurs. Yet another advantage is that the open Or unenclosed exterior of the pile avoids the collection of moisture or carbon dust thereon.

In order to enable the invention to be readily understood, reference is made to the accompanying drawings, wherein:

Figure l is a cross sectional plan of a carbon pile and cooling means applied thereto in accordance with the present improvements Figure 2 is a sectional plan of a modified form of cooling rod and insulation sleeve enclosing the same.

Figure 3 is a sectional elevation illustrating means for filling the annular space between the cooling rod and the sleeve shown in Figure 2, and

Figure 4 is a perspective view of a double carbon pile regulator enclosed in a casing and having cooling fins fitted externally of such casing;

part of the latter being removed in order to disclose the regulator parts within.

Referring to Figure 1, a stack of carbon rings a is passed on to a relatively thin tube b of electrically resistive or insulating material to form a carbon pile, and a conductive rod, for example a copper rod c is inserted into the tube b.

The rod c is shown as having a close fit in the tube 12. The length of the rod c'is greater than that of the tube 1) so that its ends are extended beyond the ends of the tube b, the two extensions c being of reduced diameter. If desired, however only one of the ends of the rod 0 may be so extended. d, al are frame or casing parts supporting or enclosingthe pile. The extension 0 is passed through the frame part d and receives alternated spacer washers e and cooling fins or plates 1. A nut g screwed on the end of the extension 0 tightens the assemblage of washers e and fins ,f and secures one end of the rod 0 tightpreventing escape of the powder or granular material n from this end of the tube b. At the other end where the extension 0 joins the rod 0, the latter is provided with a screw threading p for the reception of a cylindrical nut q. A compressible packing washer 0 which is interposed between the nut q and that end of the tube 12 acts as a stopper at such end of the tube when the nut q is tightened.

The material 11, when of a granular or pul- "verulent nature may be introduced into the anly against the frame part :1 a suitable washer m being interposed. The extension 0 is passed through a flanged sleeve h inserted into a; hole in the frame part d The sleeve it receives an assemblage of spacer washers e and fines I which.

is tightened by a nut :i screwed on to the sleeve 71., which nut 7' also secures the sleeve h in the frame part d by drawing the flange of the sleeve against the frame as shown. A nut g screwed on to the end of the extension 0 secures the other end of the rod 0 against the frame part 11 by drawing the annular shoulder at this end of the rod against a washer m seated'against the flange of the sleeve h. The purpose of the sleeve or bush h is to hold together the fin assemblage at this end as a single unit, so that on removal of the fixing nuts y, g this fin assemblage can be removed as a unit.

One end of the pile is supported by a fixed abutment plate is supported on the frame part d and provided with a terminal connection Z. The other end of the pile is compressively operated upon by a presser plate k whichhas the other terminal connection 1 The means for operating the presser plate k under the combined influence of the regulator spring and electrio-magnet are not illustrated, as any known means may be employed and such means form "no part of the present invention. The carbon rings a are in suitably good heat contact with the tube 1) which may possess good heat conductivity whilst possessing the necessary electrical insulating properties. Thus, heat developed in the pile is taken up by the tube b within the pile and transferred to the rod 0. Such heat is conducted along thev rod 0 and is radiated to the atmosphere by the fins or plates By this means, the pile is eificiently cooled from its interior and its exterior is accessible and easily observed over its whole length,

If desired, suitable peripheral formations of the rod 0 and corresponding internal formations of the tube 1) may be adopted for increasing the area of contact between the rod and the tube.

Or, the inside of the tube b may be coated, as

with silver, and then soldered to, or otherwise given a close union with, the rod 0.

According to a modification and as illustrated in Figure 2, the rod 0 is made with a diameter somewhat smaller than the diameter of the bore of the tube b. The rod is centrally disposed in the tube so that an annular space is provided which is filled with heat conductive material 11. This material may be a heat conductive cement, or lead or solder but it may also be a granular or pulverulent material such as magnesium oxide powder or finely divided metal particles such as copper precipitate. When a powder or granular mass is used the rod 0 may be formed with a collar or flange 0 where it is joined by the extension 0 the said flange (2 providing a seating for a compressible .packing washer 0 which serves for nular space between the rod 0 and tube 12 in the manner now to be described with reference to Figure 3. An assemblage consisting of the rod 0 of Figure 2 with the washer 0 seated against the flange c and the tube 12 surrounding the rod and having its bottom end abutted against the washer a, has its lower end inserted into a holder or.

the hopper firmly on the tube 12. A suitable con- 7 nection, not shown, is made between the hopper s, or the socket r, or both, and the armature or trembler of an electro-magnet energized by alternating current or by interrupted direct current. In this way, a trembling or lateral shaking oi the assemblage, in the direction of the arrows in Figure 3 is achieved so that the material from the hopper 8 passes down into the annular space between the rod 0 and tube b, filling the said space and becoming compacted therein. The nut t and hopper s are finally removed and the washer 0 and nut q of Figure -2 are applied, the rod 0 and tube b being then ready to receive a pile of carbon rings and to be mounted in a similar manner to that described with reference to the pile illustrated in Figure l.

Reference is now made to Figure 4 which shows a regulator comprising twin piles but only one of these is seen, its carbon rings being marked a as in the case of the pile illustrated in Figure 1. However, the two nuts g g screwing on to the extensions 0 of the cooling rods 0, as described with reference to Figure l, are seen in Figure 4. The piles are put under compression by springs, such as the one marked it, the action of these springs being opposed by the pull of the regulator magnets 21 on armatures w the latter being on lever arms 20 engaged with the springs u. It is not necessary to describe the particular means employed for transmitting to the piles the resultant effect of the springs and magnets, as the present invention is concerned only with the cooling of the piles. In the example illustrated in Figure 4, the radiator devices, for cooling the core rods of the piles a, are four sheet metal plates 1: r :0 r spaced on the extensions 6 of the said rods, a similar set of plates being spaced on the extensions of the rods at the opposite side of the regulator, but the latter extensions (marked 0 in Figure 1) are not seen in Figure 4. These plates 3: to m are common to the two piles and may be spaced by the aid of spacing washers such as those marked e in Figurel. The plates :0 support the core rods as described with reference to Figure 1. The radiator plates 33 to at? are additionally supported in spaced relation by means of bolts and nuts 2, these bolts being passed through frame parts, as will be readily understood. The plates 9: and r may be of any suitable metal but the plates .11 are advantageously of iron or steel in which case they act not only as heat radiator plates but also as magnetic screens for reducing stray field from the magnets 11. This screening of the magnets is of importance on aircraft, for example, where compass readings are liable to be affected by such stray field. A cover 2 is applied for enclosing the regulator mechanism and the side walls of such cover are conveniently inserted between the plates 3. An electric resistance pile comprising a pile assemblage of annular resistance elements, an electrically insulating tube centrally supporting said assemblage, a heat conductive core extending through said tube, a heat conductive layer between the exterior of said core and the interior of said tube, and heat radiating means fitted on x and x at each side, as illustrated, portions of I the side walls of the cover being cut away, as indicated in dotted lines, so that the said side walls clear the extensions 0 (2 of the core rods and the bolts of the nuts 2. The outer edges of the plates m and x are curled away from one another, as shown, to provide a flared entry for the side walls of the cover. The outer edges of the plates .13 x are curled towards one another to give a better appearance and to impart stillness. Figure 4 is drawn as when the base plate 1; rests upon a horizontal surface. Usually however, the apparatus is supported on a wall so that the base plate 11 rests against a vertical surface with the front edge in Figure 4 lowermost. It will now be apparent that the two radiator plate assemblages x to x radiate heat from, and effect the cooling of, the core rods of the two carbon piles forming part of the regulator mechanism seen in Figure 4.

I claim:

1. An electric resistance pile comprising a pile assemblage of annular resistance elements, a heat conductive core extendin through said assemblage, an electric insulation layer between said core and said assemblage, and heat radiating means fitted on the ends of said core beyond the ends of said assemblage.

2. An electric resistance pile comprising a pile assemblage of annular resistance elements, an electrically insulating tube extending through and concentrically supporting said assemblage, a heat conductive core extending through said tube, and heat radiating means fitted on the ends of said core beyond the ends of said assemblage.

an end portion of said core beyond the ends of said assemblage.

4. An electric resistance pile comprising a pile assemblage of annular resistance elements, an electrically insulating tube centrally supporting said assemblage, a heat conductive core extending through said tube said core having a diameter smaller than the internal diameter of said tube, a filling of pulverulent heat conductive material compacted into the annular space between said core and said tube, and heat radiating means fitted on an end portion of said core beyond the ends of said assemblage.

5. In an electric regulator embodying a plurality of resistance piles each comprising a pile assemblage of annular elements with a heat conductive core extendin through said assemblage and an electric insulation layer between said core and said assemblage, the combination with said piles of an assemblage of heat radiator elements fitted on to end portions of the cores extending beyond said piles whereby said assemblage of heat radiator elements serves for the cooling of a plurality of cores.

6. In an electric regulator embodying a plurality of resistance piles each comprising a pile assemblage of annular elements with a heat conductive core extending through said assemblage and an electric insulation layer between said core and said assemblage, the combination with said piles of a plurality of heat radiator plates fitted on to end portions of cores extending beyond said piles one of said plates being of magnetic material to serve as a magnetic screen for the regulator whilst also serving as a radiator plate for cooling said cores.

ALFRED HENRY CHILTON.

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