US1642197A - Clamp-on electric heater - Google Patents

Description

' 1,642,197 p 1927' P. FOWLER CLAMP-0N ELECTRIC HEATER Filed Nov. 10, 1925 2 sheets she t 1 INVENTOR J CZQZIZO Irr W ATTORNEY Sept. 13, 1927. P. L. FOWLER CLAMP- ON ELECTRIC HEATER I 2 Sheets-Sheet 2 Filed. NOV. 10, 1925 ATTORNEY Patented Sept. 13, 1927.

UNITED STATES PATENT OFFICE.

PAUL L. FOWLER 0F SPOKANE, WASHINGTON, ASSIGNOR TO ARTHUR-FOWLER 00., OF SPOKANE, WASHINGTON, A CORPORATION OF WASHINGTON.

Application filed November This invention relates to improvements in electric water heaters for range boilers and has to do with that type of heater of this class which is clamped about the periphery of the boiler, and therefore, has no bearing on cir culating heaters.

One of the features of my invention is to provide a novel form of supporting band for the heater, wherein a heating element and its protecting plate is disposed on' one face of said band, and wherein a heat insulating structureis disposed on the remaining face of said'band.

In a heater of this type, flexure without interference of parts, is a great desideratum for the reason that these heaters are initially made flat, and shipped and sold flat, and when they are installed, they are bent around and tensioned to firmly engage the periphery of the boiler. Now as the heater is made up of a plurality of band-like layers of material, it is a feature of my invention to connect these layers or integers in such a manner that they can bodilv partake of relative longitudinal displacement, due to flexure, without interference. This feature of my invention also greatly facilitates assembling of the heater at the place of manufacture. This feature of my invention is also important by reason of the fact that the layers or integers of material of which the heater is made up, are all of different material.

It is a feature of my invention to provide a heating element which is completely insulated, and to completely enclose said element on the tank or boiler side of the supporting band and also provide the latter with a terminal box whereto the terminals of the element are connected and extended through the supporting band for this purpose.

It is a further object of this invention to make the heaters of a given or uniform length, irrespective of the heating capacity thereof, for boilers of different diameters,.

' and to provide means whereby the heaters may be clamped onto any of the usual SIZB' boilers.

The invention has many other objects and features which will be more fully described in connection with the accompanying drawings, and which will be more particularly pointed out in and by the app In the drawings Fig. 1 is a horizontal ended claims.

sectional view of a CLAMP-ON ELECTRIC HEATER.

1Q, 1925. Serial N0. 68,205.

range boiler showin the device of my invent1on clamped therea hout.

Fig. 2 IS a view in elevation, on an enlarged scale, showing the heater flat, and look ng toward the tank or boiler side of the heater.

F 1g. 3 is a view of the heater looking to- Ward the outside face thereof.

Fig. 4 s a top edge view of the terminal end portion of the heater looking .downwardly on the left hand end portion of Fig. 2.

Fig. 5 is a similar view of the right hand 7 end portion of Fig. 2.

Fig. 6 is a sectional view on line 66 of Fig. 4. 1

Fig. 7 is a sectional view on line 7-7 of Fig. 4.

Fig. 8 is aview in elevation on a small scale showing how the integers of the heat insulating structure are united.

Fig. 9 is a view in elevation, on a small scale, of the heating element showing the manner of coiling the same and disposing the.

terminals near the end of said element. Fig. 10 is a view of the same after the inner envelope has been formed.

Fig. 11 is a sectional view on 1ine.1111 of Fig. 9. v

Like characters of reference designate similar parts throughout the different figures of the drawings.

Referring to the specific form shown, 9. preferably metallic and flexible supporting band is employed having a central or main body portion 1. The terminal end 2, of said band 18 doubled or bent back upon or against the body portion 1, and secured in abutting relation as by means of rivets 3, thereby increasing the strength of the material at this point. In the bight of the bend, as at 4, I dispose a rod 5, and with suitable openings 6, I provide access for connection of clamp- I on chains 7, two being shown. The bent 10. In the wall of said box 8, is a suitable,

conduit opening 11, through which conductors may be extended for connection with terminals in the box. A block of insulatin material 12, is disposed in said box 8, an may be anchored by screws 13 extending through the block and through the support? against v tents and ing band, as shown in Fig. 6. Thus, it will be seen that the terminal box is carrled by the supporting band and preferably at the terminal end thereof. Hereinafter, I Wlll refer to the manner in which the element is electrically connected with terminal posts and secured as by rivets 16, to form a double thickness, and in the bi'ght 17, I dispose a rod 18. Coupling members 19, extend through openings'20, and around rod 18, to distribute the strain of the band. These coupling members are preferably hook-shaped and in the hook ends thereof, shown at 21, are openings 22, for receiving tightening bolts, the nuts 23, thereof, impinging on the ends 21. Said bolts have hooked ends for coupling engagement with chains 7. Thus, by tightening the nuts, I.

have afforded means for clamping on a heater of uniform length, about tanks of d1f ferent diameters. I

' The extreme or terminal end 24, is bent outwardly into spaced relation to body 1, to form an endpocket, in a manner simllar to end 14, said ends forming companion pock ets for a purpose which I will next describe.

lVhile heaters of this type are applied to tanks or boilers which are enclosed by blankets or other form of enveloping insulation against radiation of heat, still, it is an portant feature to provide special insulation heat radiation outwardly abreast of the electrical element. I therefore employ an insulating structure on the outside 0 band 1, which is generally indicated at 25, I preferably use asbestos, in this capaclty, but in the event of any type being used, it is advantageous to em loy a laminated or layer structure to obtam the benefit of air spaces intermediate .the layers. Because of the outer cover with which the tanks are equipped, there is no air circulation, hence these intermediate air spaces are to all inurposes, dead air spaces, which form the i Now it is well known that asbestos, especially in thick band form, does not lend itself well to bending movement, and that it also has great friction against asbestos. Hence,-the problem of using asbestos in a flexible heater that must be flexed, involves the necessity of provision for relative displacement of the layers, and I have solved this problem in the followin manner.

As shown, I use four ban '-like strips of asbestos, the inner and outer bands 26, are

throughout the width f band, and I frictionally and slide.

est type against heat radiation.

relatively thin, and the two intermediate bands 27, are relatively thick. In'practice, these bands are disposed in flat abutting relation and because they are floatin ly supported, and also to afford relative 'splacement of the bands, I unite the same preferably b luing them together substantially centrally between their ends, as indicated by dotted lines 28 in Fig. 8. Thus, all the integers are united to form a unitary insulating structure with the end portions 29, free from connection with each other. This structure 25, is disposed abreast of the outer face of supporting band 1, in the manner shown, with the ends of said structure in the open sided pockets formed 'by the supporting band ends 14 and 24. I preferably energize said ends 14 and 24, to lmpart a frictional grip 'on the structure 25, and as shown, this 1s accomplished by a plurality of tension springs 30, having their ends secured to the edges of parts 14 and 24. These springsout their length against the structure 25,

helping thus, to frictionally support the latter on the supporting band. When the heater is flat, the portions 31 and 32 impinge against the ends of the structure 25, to support the latter in place, and when the heater is flexed, the free end portions thereof move relatively to each other because of the reater radii about which tht outer band nds, as regards the radii of the inner bands, and then tension is a plied not only lengthwise by springs 30, an the friction of parts 14 and 24 is increased artly by reason of the resistance of said ban s against bending movement. At any rate, I floatingly mount the structure 25, on said sugporting ly support said structure thereon.

Before describin the structure of my improved heating e ement I will first refer to the same generally and will describe the means and manner of its mounting in the heater. I

The element is designated at 33, and is disposed abreast of the inside face of band being shown in Fig. 2. The band 1, is shown reduced at 34, this reduction being the result of slitting the upper and lower margins of band 1, to form the series of lugs 35. .lt will be noted that the band 1 .is slit to dispose the lugs 35 in spaced relation with respect to each other, their lateral and adjacent edges being free from engagement. I employ what I will term, a hard surface heat conducting contact band 36, preferably of'copper, said band being longer and wider than the element 33, but of less width and length than body 1, of the supporting band.

mm- M at...

, 1, the relative length and width of the two slidable mounting of the contact plate or band 36, on the heater. The lugs 35, are disposed endwi'se of body 1, sufiicientlyto h old end portions of band 36 in fiat abutting xrelation against body 1, whereby the element 33, will be completely enveloped by body 1 and band 36. It will be noted from Fig. 6 that the upper and lower margins of ban 36 extend inwardly over theedges of the element 33, so that the rectangular bulge formed in the band 36, by said element, may

' be uniformly pressed against the boiler with-- out any. interference on the part of the en the heater is flexed about the boiler, the spaces between lugs 35, avoid interference, and not only the contact band 36, but

. also the element and supporting band 1, can

placement necessitated by suc partake of the relative lon itudinal disflexure. for any reason, it is necessary to remove or renew the element, it is an easy matter to withdraw the slidably mounted contact band 36, to render the element accessible, without totally dismantling the heater or evensending it back to the manufacturer or place of purchase, and without extreme delay in hot water service to the user. Further the metallic-band 36, will wear practically indefinitely and fully protects the element from wear, therefore, I consider it an important feature of my invention that the heating element is disposed inside or alongside a hard surface, high heat conducting or metallic contact band, and, as shown, between a hard surface or metallic supporting band and said contact band.

I will next refer to my improved heating element which I consider new, as an. article of manufacture, and also in the combina-' tion set forth.

Referring to-Figs. 9 to 11, 37 indicatessomewhat wider and longer than the sheet- 37. The element 39 is disposed in the manner shown, and both terminals 40, are extended from one end of the structure. In practice, I shellac or otherwise fix the wire to the sheet 37 and then place thereover, a similar sheet of asbestos 41, so that the coil is enclosed, first, in an asbestos casing. I then add an additional sheet of mica 42, of less width than sheet 38, so that the edges 43, of sheet 38, can be bent over, as shown in Fig. 11. In the drawings, I have shown the thickness of the materials greatly exaggerated, for clearness of illustration, but the mica and asbestos sheets actually employed, are so thin that the resultant double envelope shown, practically has no projections and is to all intents and purposes substantially fiat. I do not, in practice, secure the ends of the coils, which I will desi ate 44, and -which are shown wavy in. ig. 9, but leave-them loose, not only to afford an extra length for connection with the terminal box, but todnsure that there shall be no such connection between the heating element and the. heater such as would prevent the former from being truly .floatingly mounted in the latter whereby the heater maythus participate in the rela tive displacement necessitated by fiexure of "the heater. It will be clear, especially by referring to Figs. 6 and 7, that the contact late 36, is frictionally engaged against the e ement, and the latter is en aged against body 1, of the supporting band, throu hout thelength and width of the element. Ihus, with this construction there is no diificulty in obtaining a firm and uniform engagement ofthe contact band against the boiler.

As will be seen by Fig. 6, the terminals 40, are extended through properly insulated openings in the supporting band and through the block 12, and are connected with binding posts 45, whereto the supply conducting wires may also be connected, as will be clear to those skilled in the art.

Now it will be clear, that my heating element coil is mounted, and substantially fixed to an inner envelope of asbestos, or the like, and the latter is encased in an envelope of mica, thereby providing a double insulation, which, in actual service, stands up under the devastating effects oflightning, with less loss ofcoils than any heater of this type known to me. I

Further, this novel form of insulated heating element enables me to dispose the same between, and encase it in metal, with the heretofore described advantages of firm and uniform contact with the boiler. One great advantage of using an outer envelope of mica, is that it presents a hard finished surface to the metal and thereby facilitates movement of the. parts under flexure of the heater. 7

While I have described one specific form of my invention, I do not wish to be limited thereto except for such limitations as the claims may import.

I claim 1. In a flexible clamp-on electric heater for range boilers, a band-like insulated heating element, a thin contact band adapted to be disposed a ainst the inner face of said element and a out the boiler and having a width and length in excess of that of said element, and a supporting band disposed along the outer face of said element and having means engaging the upper and lower margins of said contact band to hold the latter and said element in position, said means being disposed beyond the margins of said element and flexing the end and side margins of said thin contact band against said supporting band to envelope said element.

2. In a flexible clamp on electric heater for range boilers, a flexible electrically in-, sulated band-like heating element, and a flexible supporting band having means for supporting said element abreast of the inside face of said band, and said band having flexible means for supporting a heat insulatin structure abreast of the outside face of said band.

3. In a flexible clamp-on electric heater. for range boilers, a flexible electrically insulated band-like heater element, a metallic contact band of greater length and width for range boilers,

than said heating band, and a flexible sup porting band having its upper and lower margins slit to form lugs adapted to be bent over and against the upper and lower margins of said contact band to dispose said margins and also the ends of said contact band in abutting relation against said supporting band to completely enclose said heating element.

insulating material onto said supporting band. 7

5. In a flexible clamp-on electric heater a flexible supporting band provided with an electric heater; abreast of its inner face, band-like inte of heat insulating material abreast of t e outer face of said band disposed in abutting relation with the inte ers united between their ends,

and said ban having spring tensioned ends outwardly overlapping the ends of said integers to frictionally support said integers on said band and permit relative longitudinal displacement of the ends of said integers as the heater is flexed about the periphery of the boiler.

6. In a flexible clamp-on electric heater for range boilers, a flexible supporting band rovided with an electric heater abreastjof 1 1ts inner face, end portions of said band being bent outwardly and back against and secured to the outer face of the body of said band, a rod disposed in the bights of said bent over ends, means connected with said rods for tightening said band and its heater into snug engagement against the periphery of a boiler, the terminal rtions of said outwardly bent ends being isposed in spaced relation to the band, and a heat insulating structure abreast of the outer face of said band and the ends of said structure being interposed between said band and said spaced terminals.

7 In a flexib'le clamp-on electric heater for range boilers, a flexible supporting band,

an electric heater element structure floatingly supported on the inside face of said band, and. a heat insulating structure floatiJngiy supported *on the outside face of said In testimony that I claim the foregoing as my own, I hereby aflix my signature.

PAUL L. FOWLER-l

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