US2323743A - Ventilated resistor - Google Patents

Description

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C. C. WHITTAKER VENTILATED RESISTOR Filed April 1l, 1941 A July e, 1943.

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Patented July 6, 1943 UNETED STATES PATENT OFFICE 2,353,743 VENTELATED RESISTGR Charles C. Whittaker, Pittsburgh, Pa., assigner to Westinghouse Electric & Company, East Titt'sliur of I ennsylvania Manufacturing gh, Pa., a corporation Application April 11, 1941, Serial No. 388,058 13 Claims. l (Cl. 24H-174) My invention relates, generally, to resistors and A further object of my invention is to provide x for more rapidly dissipating heat from a resistance element of the edge-wound type so as to permit a relatively small resistance element to handle safely large amounts of power.

Another object of the invention is to utilize internal core members and external baffle members with. resistance elements of the edge-Wound type to provide a plurality of ducts between the adjacent turns of the elements which present relatively low resistance to the flow of a cooling medium.

Another object of my invention is to provide for supporting a resistance element of the edgewound type by baiiie members on each side oi the element which function to direct the flow of a cooling medium between adjacent turns of lthe element.

Still another object oi my invention is to pro'- vide for supporting a plurality of edge-wound l resistance elements in spaced relation by means oi' baille members positioned between the elements to substantially l the space therebetween and direct cooling medium between the adjacent turns oi the elements.

4 A further object of my invention is to provide for mechanically interlocking a plurality of re- Other objects will in part be obvious, and will in part be explained hereinafter.

My invention provides a highly eiiicient ventilated resistor for application Where the amolint of power to be handled is large 'and the space available is small without the danger of excessive heating. In practicing the invention in a preferred form, the resistance elements may each comprise a plurality of turns of a ribbon of suit, 55

able resistance material wound on edge in a generally helical shape. Refractory core members are positioned within the element and provided with spaced ribs er projections for supporting the turns in spaced relation, and baille members of a refractory material are positioned between the adjacent elements to substantially nll the space therebetween. The baille members are provided with enlarged end portions onthe with the cere members a plurality of ducts be- 'lhe resistor is or" the resistor unit shown in Fig. 1;

Fig. 3 is an enlarged plan View of the resistor shown in the resistor unit of Fig. 1;

Fig. 4 is an enlarged vertical sectional View along the line IV-IV of Fig. 3;

Fig. 5 is a front elevational View of a modified form oi resistor embodying the principles of the invention;

Fig. 6 is a sectional view taken along the-line Fig. 7 is an enlarged partial view in section taken along the line VIIVII of Fig. 5;

Fig. 8 is an enlarged partial View in section taken along line VIII-VIII of Fig. 5; and

Fig. 9 is an enlarged partial vView in section taken along the line IX-IX of Fig. 6.

Referring to Figs. 1 and 2, the reference numeral I0 may denote, generally, a ventilated resistor unit comprising a resistor I2, which may be positioned within an enclosure I3 and 4provided With Ventilating means such as the blower I4 for directing a cooling medium such as air therethrough.

The enclosure I3 may be of any suitable construction, comprising, for example, a frame structure I5 having partitions I6 with openings I1 therein, positioned intermediate the top and bottom to divide the enclosure into sections. The upper section may be enclosed at the sides by means of suitable side panel members I8, and provided with an opening I9 at the top. The resistor I2 may be supported in the upper section in any suitable manner, such as by means of bracket members 20 secured to the frame structure.

The blower I4 may be positioned between the partitions I6 and the openings I1 therein utilized as inlets and outlets therefor'. The blower I4 may be driven by a motor 2I, which may be mounted in the lower section of the enclosure and connected to the blower by a belt 22. The central and lower sections of the enclosure I3 may be provided with perforated side panel members to substantially enclose the motor and blower, and provide for the ingress of air to the resistor. A suitable terminal board 24 may be mounted adjacent the resistor for making connections thereto.

Referring to Figs. 1, 2, 3 and 4, it will be seen that the resistor I2 may comprise a plurality of elongated resistance elements 25, supported between end frame members 25 of insulating material by means of tie rods 21, which may be connected to the bracket members 20. Side frame members 28 may be secured between the end frame members 26 by means of angles 29 to substantially enclose the elements on all sides.

The resistance elements 25 may comprise spaced turns 3l) of a ribbon of suitable resistance material wound edgewise and generally helical in form. While the elements are shown as having circular sections, it will be understood that they may have other sections, such as oval or flattened circular sections without departing from the scope of the invention. Core members 32 of refractory material having serrated surfaces may be positioned within the elements to maintain the turns in spaced relation. The core members may be mounted on the elongated support bars 34, which may be provided with slots 35 on the inner surfaces to receive the bars. The ends of the bars may be provided with slots 36, as shown in Fig. 2. to receive the tie rods 21 andy support the bars thereon. Tubular spacers 38 may be positioned on the tie rods 21 between the support bars 34 to maintain the elements in spaced relation.

In order to provide for cooling the resistor elements 30 in a most efficient manner. suitable means, such as the baille members 40 may be positioned between the adjacent elements to substantially fill the spaces therebetween and force the cooling medium to pass directly between the adjacent turns of the elements. The baille members 46 may be made of any suitable refractory material capable of withstanding relatively high temperatures, and may be positioned between the adjacent elements in any suitable manner. For example, opposite sides 4I of the baille members 40 may be dished transverse to the longitudinal axis of the element, as shown, conforming, generally, to the curved edge portions of the elements 25. The baffle members will, therefore. have substantially dumbbell shaped sections which are narrower in the mid portion and wider adjacent the ends. When the baille members are positioned between the adjacent elements, the enlarged end portions 42 mechanically interlock with the elements and prevent movement of the baffle members transverse to the longitudinal axis of the elements, thus securely positioning them therebetween. If desired, the baille members 4D may be provided with projecting ribs 43 along the front and back edges of the dished surface portions so that direct contact with the resistance elements may be made by means oi the projecting rib portions, thus making it easier to align the baffle members with the resistance elements, since the area of contact therebetween is thus greatly diminished and variations of dimensions in manufacturing are rendered less material.

Referring to Figs. 5 through 9 of the drawings, the reference numeral 45 designates, generally, a mcdiiied form or resistor wherein a plurality of resistance elements 45 comprising spaced turns 41 of a ribbon of resistance material wound on edge may be supported between the end frame members 48 by means of a plurality of refractory baille members 5D, secured to the end frame members by means of tie rods 5I.

As shown in Fig. 7, the resistance elements 46 may be supported on elongated metallic support bars 52 by means of refractory core members 53 positioned on the opposite edges of the support bars. The core members 53 may be provided with serrated surfaces so as to form projecting linger portions 54 at spaced intervals which may be positioned between the turns of the resistance element to retain them in spaced relation.

The end frame members 48, which may be of a suitable insulating material such as, for example, asbestos board, may be provided with a plurality of transverse slots 55 having recessed portions 56 adjacent the central portion of the end frame for receiving the ends of the support bars 52. Suitable openings 51 may be provided in the end frames in alignment with the slots 55 to receive terminals 58, which may be provided with an enlarged head portion 59 having a projecting rib 6I) adapted to be positioned in the slot 55 to prevent the terminal from turning. The resistance elements 46 may be connected to the terminals 58 in any suitable manner, such as, for example, by means of the welds 60.

In order to provide for directing a cooling medium between the adjacent turns of the resistance elements 45, and for also supporting the elements, the baffle members 50 may be provided with surface portions 62 on the opposite sides thereof conforming, generally, to the curvature of the outer edges of the resistance elements and rounded end portions 63 on the front and back having substantially greater width than the midportion oi" the baille member, as shown in Fig. 9. Suitable longitudinal openings 66 may be provided through the enlarged end portions of the baille members to receive the tie rods 5I and tubular spacing members 66, which enable the nuts 61 on the tie rods to be drawn tight without applying excessive pressure to the baffle members themselves.

Since the baille members 50 which are positioned between the adjacent resistance elements 46 have a substantially dumbbell shaped section, pockets are, in effect, provided between the adjacent balile members for receiving the resistance elements. Because of the enlarged end portions of the baille members, the resistance elements are securely locked in position between the adjacent baille members. which not only provide for directing a smooth and uniform flow of cooling medium between the ducts, thus formed between the adjacent turns of the resistance elements and the baille and core members, but also assist in positioning and supporting the resistance elements.

Since the `elements are effectively .supported throughout their length by the baille members 5B, vthe elements may be made much longer than usual, vwithout any danger of sagging. The resistor of Figs. 5 through 9 is shown as having a single row of resistor elements. Such a resistor' may be used in applications where only a relatively loW pressure is available for forcing the cooling medium therethrough. Where greater pressures are available and greater capacity is needed, such units may be arranged in tandem as desired.

From the .above description and the accompanying drawings, it will be apparent that I have provided a simple and efficient ventilated resistor vwherein the baille members, which are interloclred Awith the resistance elements, may be supported Vby o1' may themselves support the resistance elements. A smooth, non-turbulent flow of a cooling medium may thus be confined tothe immediate space between the adjacent of the resistance elements so that efficient cooling the elements may be secured and relatively large kamounts of power may be handled with a rele.-

tively small resistor requiring only a relatively low pressure to force the cooling medium through the cooling ducts.

By utilizing with resistors of the edge-wound type baille members Aof the type l have hereinbefore described, whereby the resistance element and baille member are mechanically interloclied, much greater heat dissipation may be secured vfrom a given length of resistance t-.an was lie etofore possible.

With the arrangement shown 5 through 9, the resistance elements be safely operated at much higher temperatures `than heretofore without fear of sagging. In addition, longer elements may be used, since the baille members interlock therewith and support the elements, since the path of the or other cooling medium is limited the baille members to substantially the between the turns of the elements. For a given volume ef air, more than .ten times the usual heat dissipation secured merely blowing air between the elements may be obtained by utilising the arrange- .ent embodying my invention,

.Since different embodiments of the invention may be made.. and changes made in the rawi -s and above description without departing from the spirit thereof, it is intended that all matter centained in the above description or shown in the accompanying drawings shall be considered as illustrative, and not in a limiting sense.

I claim as my invention:

1. A resistor comprising elongated core member of insulating material, a resistance element including a plurality of spaced turns of an edgewise wound ribbon of resistance material of generally helical form positioned about the core member, and a pair of elongated baffle members of insulating material so positioned on opposite sides of the element and having transversely curved surface portions in juxtaposition to the outer edges of the turns o-f the resistance material so shaped as to denne with the core member a plurality of relatively long arcuate channels between adjacent turns of the element throughout substantially the full length of the element.

2. An elongated resistance element comprising, an edgewound ribbon of resistance material formed generally into a helix, a core member positioned within the element, and an elongated baille member positioned on each side of the reysistance element `having :a 'longitudinal groove conforming generally to the outer portion of ative movement of the element and baille member .in a direction transverse to the longitudinal axis of the element.

3. Aresistor comprising, a generally helical resistance element having a plurality of spaced turns of resistance ribbon Wound on edge, a refractory core member positioned within the element, and a pair of elongated =baille members positioned on opposite sides of the element having transverse curved surface portions positioned in engagement with the outer edges of the turns vthereof cooperative with the core member and the turns of the resistance ribbon to define a plurality of relatively long open ducts conned between the adjacent turns for a cooling medium throughout substantially the `length of the element.

4. The combination with a resistor having an elongated resistance element comprising ya plurality of edgewise wound turns of ribbon of resistance material positioned in spaced relation .on a core member, of a pair of elongated refractory baille members having surface portions conforming generally to the Vconteur of the outer edges of the turns of the element transversely and contiguous therewith throughout substantially the length of the element positioned on opposite sides of the element to partially enclose the element and define with the core member a plurality of arcuate ducts between the adjacent turns from one side of the element to the other.

V5. A .resistor comprising, a frame, an edgewound resistance element having spaced turns of resistance ribbon of generally helical shape, a refractory core member positioned within the element having a plurality of spaced teeth between the turns of the element, and refractory members supported in the frame having surface `portions conforming .generally to and engaging the outer edge portions of the element through- -out substantially the length of the element positioned in opposed relation on opposite sides of the element to secure the resistance element therebetween and to denne a plurality of ducts .between and bounded by the turns of the element for ra cooling medium.

6. The combination in a resistor, of a plurality of elongated resistance elements comprising spaced turns of a ribbon resistance material wound on edge, a core member positioned Within each element and connected to a supporting frame, and baille members positioned in substantially 4continuous end to end relation between Yadjacent elements having curved surface portions .conforming substantially to the adjacent portions of the element shaped to define with the core member a plurality of arcuate ducts of substantially the width of the ribbon from one side of the element to the other and enlarged end portions on opposite sides of the elements projecting inwardly to partially enclose the elements and interlock mechanically in a transverse direction with the said elements` to provide a substantially continuous baille throughout the length of the elements and to retain the baille members in end to end relation between the elements.

7. The combination with a resistor having a plurality of elongated edgewound resistance elements with a plurality of turns of ribbon resistance material wound on edge and positioned on core members supported in a frame, of a plurality of baiiie members having generally dumbbell shaped sections with opposed surfaces conforming generally to the outer edges of the turns of adjacent elements to define with the core member relatively long arcuate ducts of substantially the width of the ribbon from one side of each element to the other and enlarged portions on opposite sides of the elements positioned between adjacent elements to interlock mechanicallly therewith and secure the baiiie members between the elements.

8. A resistor comprising, a plurality of elongated resistance elements having a plurality of spaced edgewound turns of ribbon resistance material, a plurality of core members having spaced nger portions positioned within the elements to maintain the turns thereof in spaced relation, a frame structure, and a plurality of bailie members extending substantially continuously throughout the length of the elements positioned between the elements and supported by the frame structure having recesses on opposite sides to receive and partially enclose the outer edges of the turns, whereby said baiile members support the elements between adjacent bafe members l,

against movement transverse to the longitudinal axis of the elements and dene a plurality of ducts between the turns thereof.

9. A resistor comprising, a plurality of resista-nce elements comprising generally helical edgewise formed spaced turns of a ribbon resistance material, a frame, means including refractory core members positioned within the elements to support them in spaced relation in the frame, and a plurality of refractory baie members positioned in juxtaposition between adjacent elements having opposing surface portions substantially contiguous with the outer edges of the turns of the adjacent elements shaped to define with the core member arcuate ducts between adjacent lturns for a cooling medium and enlarged end portions on each side of the elements having a width greater than the space between adjacent elements to interlock mechanically with the elements and secure the baille members relative to the frame.

10. A resistor comprising, a plurality of elongated resistance elements positioned in spaced relation with openings therebetween and having edgewise formed spaced turns of a ribbon of resistance material, a core member positioned within each element having spaced projections on the outer edge positioned between the turns to maintain them in spaced relation, a frame having spaced end members, a plurality of refractory support members positioned in the openings between adjacent elements having surface portions adjacent the elements throughout the length of the elements conforming generally to the outer edge portions of the elements to provide substantially enclosed ducts between the turns thereof in a direction substantially transverse to the longitudinal axes of the elements for a cooling medium and restricted portions between adjacent elements with enlarged end portions on the front and back sides of the openings between the elements partially surrounding the elements so as to interlock mechanically with the elements and position them in the frame, and means connecting the end members operative to secure the support members in the frame.

11. A resistor comprising, a plurality of spaced apart resistance elements of a ribbon resistance material wound on edge in a generally helical shape with spaced turns, a core member positioned within each element having projecting portions to retain the turns thereof in spaced relation, a plurality of baffle members having generally dumbbell shaped sections positioned between adjacent elements to interlock mechanically therewith and provide ducts between the adjacent turns of the elements for a cooling medium, end frame members, rigid connecting means securing the end frame members in spaced relation effective to secure the baiile members to the end frame members, and terminal members connected to the resistance elements mounted on the end frame members.

12. A resistor comprising, an elongated edgewound ribbon resistance element of generally helical form, a plurality of refractory core members positioned within the element having surface recesses to receive the turns to maintain them in spaced relation and an elongated metal support positioned within the refractory core members, a terminal secured to an end of the element having a headed stem with a projecting rib on the stem side of the heady an end frame member having a transverse slot to receive an end of the elongated metal support and the projecting rib of the terminal, a pair of refractory baille members positioned on opposite sides of the element having surface portions adjacent the element conforming generally to the outer edges of the turns of the element and enlarged front and back end portions interlocking mechanically with the element, and means to secure the baiile members to the end frame member with the element therebetween.

13. A resistor for use with means for producing forced ventilation comprising an elongated resistance element having a plurality of spaced edgewise wound turns of a ribbon resistance material positioned on a core member and supported in a frame, of a baiile member extending along each side of the element throughout the length thereof having a longitudinal groove to receive the outer portions of the element shaped to define relatively long and narrow ducts bounded by the turns of the ribbon and interlock mechanically therewith in a transverse direction.

CHARLES C. WHITTAKER.

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