US1416872A - Electric heater - Google Patents

Description

J. H. QUAIN. ELECTRICHEATER.

APPLICATION men JULY 26, 1920.

Patented May 23, 1922.-

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J. RPQUAINJ ELECTRIC HEATER APPLICATION FILED JULY 26, 1 920.

Patented May-23, 1922.

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J. R. QUAIN. ELE CTRIC HEATER. APPLIATION FILED JULY 26,1920.

1,416,872} Patented May 23, 1922.

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I nventor PATENT OFFICE.

JOHN ROBERT QUAIN, OF LONDON, ENGLAND.

ELECTRIC HEATER.

Specification of Letters Patent.

Patented May 23, 1922.

Application filed July 26, 1920. Serial No. 399,121.

To all whom it may concern Be it known that I, JoHN Roman QUAIN. a subject ofthe King of Great Britain and- Ireland, residing at 17 Victoria Street, London. S. \V. England, have invented certain new and useful Improvements relating to Electric Heaters. (for which I filed applications in Great Britain, 1 0. 12.266, dated July. 27, 1918, and No. 13,834, dated Aug. 23,- 1918.) of which the following is a specification.

This invention relates to electric heaters of the kind in which silica is employed for the support and enclosure of the resistance element or filament.

The object of the invention is to provide a simple and effective immersion heater which may also be adapted for use as a f idiator for the heating of rooms and the According to the invention I provide the filament, which may be nickel chrome or any other suitable metallic filament. in the form of a helically wound spiral and I wind the helically wound filament upon the tubular or hollow support and apply between adjacent convolutions a strip of a nonconductor, such as asbestos, or I provide a helical rib on the support and I mount the helically wound filament in the groove between adjacent convolutions of the rib. I advantageously anchor the filament adjacent the end or at the end of the support and form a continuation of it as a wire which returns through the support to the rear end where 'bothends of the'filarnent are connected to supply conductors.

The support is mounted within a tubular casing of silica, the end of which is closed. The internal diameter of this casing is preferably such that it can be applied-upon the support so that the helically Wound filament may contact with it.

The casing of silica containing the tubular support and the filament is suitably mounted in a carrier or socket adapted to the particular purpose for which it is required.

It will be understood that on current being passed through the helically wound filament it is rendered incandescent and the adjacent part of the support and, enclosing casing are heated.

Such a heater may be used for immersion in liquids 'for the purpose of heating them and may be widely used for such purposes. It may also be used as a cigar lighter or as a lighter for other purposes or as a radiator or heater. a

The tubular support is provided of silica which possesses the capacity of retaining to a very great degree its resistance to the passage of electric current, even at high temperatures, and thus serves not only as a support to the filament but also as an insu-- lator between the leads, the return lead being conveniently carried through the bore of the support. V

It will be understood that the construction of the tubular support may be carried out in various ways. According to one construction it may be a plain tube. Accord ing to a modified construction, however, it may be provided with helical ribs formed by moulding the exterior surface of the support or by forming the support upon a helically threaded surface or by preparation in a mould by blowing as in the production of glass work.

I may provide the support for the filament of a composite construction comprising an outer member. which may be of porcelain or like material, threaded or otherwise prepared to receive the filament and an inner member or lining of silica fitting within the outer member.

The application of the invention is illustrated, by way of example, in the accompanying drawings in which- Fig. 1 represents a heater for use in heating small quantities of liquid;

Fig. 2 is a sectional view corresponding to Fig. 1;

3 and 4 are detail sectional views representing modifications in the disposition of the filament;

- Fig. 5 represents, to a smaller scale, a heater of large size intended for heating larlge quantities of liquid;

ig. 6 is a sectional elevation of a heater for use in baths;

Fig. 7 is a plan view corresponding thereto;

Fig. 8 is a detail view;

Fig. 9 represents diagrammatically a suitable switch device for the heater shown in Figs. 6 to 8;

Fig. 10 represents a heating element which is suitable for a hot water radiator, the outer cage being partly in section;

Fig. 12 represents to an enlarged scale 'the construction of the socket or carrier for the heating element shown in Fig. 10;

. Fig. 13 is a sectional elevation of a heating apparatus in which the heating element is employed for heating rooms and the like; and

Fig. 14 is a sectional view, to an enlarged scale, of a portion of the element used in the apparatus shown in Fig. 13.

In carrying the invention into effect as represented in Figs. 1 and 2, the filament a in the form of a helically wound spiral is coiled about a tubular silica support between anchoring studs 7) fused into the support. and between the convolutions is wound the strip of asbestos or other nonconductor a. The wire of the filament (1 -having been secured to the stud b is led through the support 6- and then back on itself several times and the bundle of strands so formed is twisted together, as at d, to form a conductor of relatively low resistance and at thesame time to avoid as far as possible the necessity for joints between the filament and other conductors. The other and shorter end of the filament al is similarly doubled and twisted. Short lengths of stout copper wire 6 e are twisted in with the two ends of the filament wire and connection is made with the flexible supply leads f f by means of connectors g of sheet metal, such as copper, bent around the conductors and gripped thereon under pressure.

The element so provided is mounted in a surrounding casing h of silica of an internal diameter sufficient to permit the filament a to fit therein. The casing it together with the element s secured in a socket i by means of asbestos or other suitable washers or packing v1 compressed to hold the outwardlyturned flange h of the easing it firmly in position in the socket i by a gland 71 adapted to screw into the socket i. The latter is provided with a screw threaded recess i for the reception of a handle j. The supply leads f f are conveniently led away through a borej provided through the socket i and the handle j. A wire guard or cage la is conveniently adapted to be carried upon the flange of the gland 11 w According to the modification shown in Figure 3, the filament a is anchored to the stud b at the extreme end 'of the support I) and is then carried into the interior of the support for one or two convolutions in order to secure a concentration of heat at the extremity of the element.

In the modification illustrated in Figure 4 the'support I) is provided with a tapering or reduced extremity so that the convolu' vided to receive, the casing 71 containing the element and is provided with a gland l screwing into the socket and serving to compress a packing ring after the manner hereinbefore described. The gland Z is also provided with a centrally disposed opening for the introduction of the supply leads while the socket l is provided with a handle Z by which the heater may be manipulated. The cage 7': is formed at its extremity with a small strengthening plate h which conveniently serves to support spring fingers lu serving to hold the casing hin a central position.- y

In carrying the invention into effect as illustrated in Figures 6 to 8 in the construction of a heater which is suitable for use as a bath heater and-is adapted to float on the surface of the water, a number of the elements are used having the casings it held within socker m formed in a hollow circular body an adapted to serve as a float, the casings It being maintained in position by use of glands m adapted to compress the packing rings on to engage the casings 72.. They may, however, be mounted in position within the glands in the manner hereinbefore described with reference to l igures 1 and 2 of the drawings. The upper portion of the body 122. is provided with a central opening closed by a cover plate m which is conveniently provided in a central position with an opening m for the supply leads and which is preferably fitted with a gland m adapted to compress packing around the casing of the supply conductors. The casings 72. are conveniently supported towards their lower end by means of a rod n centrally mounted on the hollow body m and having at its lower end a substantially rectangular plate a at the corners of which there are secured the rings 71, each serving to embrace one of the casings h. Spring fingers n are conveniently provided upon the rings n to maintain the casmgs in a centrally disposed positlon and to guard .them against shock. A suitable wire-work casing 0 is fitted around the lower edge of the hollow body wt and serves as a support for the heater when resting 'on a surface and feet or legs 0 may be provided on the upper surface of the body on to support the heater in the reversed position so that it may serve as a radiator. A pivoted handle p may be closed. By suchmeans the heater is at once available for usewithout the distinct and separate operation of a switch.

It will be understood that the heater may consist of a number of separate resistance elements in series or parallel. The socket of the heater and the float together with the surrounding frame or cage are advantageously provided of metal but no limitation is involved to their particular shape. It will be understood that such a heater may be adapted for use for various purposes and for heating water or liquids to any particular degree of temperature. Any other means than those indicated may be employed for mounting the heater in or upon the float in a water-tight manner.

In the application of the invention to a hot water radiator as illustrated in Figures 11 to 13 the radiator, is formed in the usual manner of a number of elements 7 which are secured together at their upper and lower ends. At the lower end of one of the outer elements a screw threaded hole is provided co-axial with the .lower communicating passage, extending through the elements, to receive a screwed plug T which, serves as the holder for a heating element constructed in the manner hereinbefore described. The plug W. is provided on its inner face with a screw-threaded recess to receive the end of the casing 71. of the element and the gland 7- by which pressure is exerted on? the washers i to maintain the casing in position. The gland is also preferably prepared to receive a metal cage 9* which serves to protect the heating element. At its outer face the plug 1' is recessed to receive a gland plate 7* and preferably a washer, the plater 1* being secured in position by means of screws. It is provided at its outer end with a gland 1 adapted to be received into a screwed recess to compress a ring of packing or the like around the flexible rubber tube or similar casing r of the leads.

In Figures 13 and 14 is illustrated the application of the heating element according to the invention to a simple form of heating radiator. and also a modified construction of the tubular silica support of the filament. The apparatus comprises a spherically or parabolically formed reflector 8 having mounted at its axis a heating element adapted to screw into a suitable sockets s of any convenient construction disposed to the rear of the reflector. A number, conveniently three, legs or feet 8 areymounted at the rear of the reflector and serve to support it either horizontally or in an inclined position. The heating element is substantially similar inconstruction to those hereinbefore described but is provided with a tubular support which is of complex form and comprises an inner tube b of silica serving to form an effective insulating and supporting member and an outer tube 6 of porcelain or the like moulded on its outer surface with a helical rib or thread serving to separate the convolutions of the filament a.

It may be found desirable in some cases to provide the heating element in a surrounding casing which is evacuated after the Y manner of an incandescent electric lamp. \Vhen such construction is adopted the support is mounted in position within the surrounding casing of silica and the adjacent edges at the end, opposite to that at which the filament is mounted. are fused together and a vacuum produced in the annular space between the support and the surrounding casing, or the support and surrounding casing may be mounted within a socket similar to that used for the reception of the bulbs of incandescent lamps.

It will be understood that the invention is not limited to the particular constructions hereinbefore described. For example, in the construction of the support, the convolutions of the filament may be separated by means of a thread. of silica fused upon the silica tube. Again in the construction of the holder for the heater shown in Figures 10 to 12, for example, the silica casing h may be retained in position within the plug 1' by means of cement instead of by means of the gland. Again, the gland plate 7" may be screw threaded so as to screw into the plug which is similarly threaded to receive it. Again, with respect to theconstruction of radiator shown in Figures 13 and 14, other means may be adopted for mounting the reflector. For example, it may be disposed upon a standard in such manner that it may be adjusted. in inclination and around the axis of the pedestal or stand.

I claim:

1. An electric heater more particularly intended for use as an immersion heater, comprising a 'helically wound filament, a support carrying such filament, means for separating the convolutions of the filament, an outer and open silica casing separate from the said support, the said filament extending of a compressed packing ring, substantially as described.

6. An electric heater as set forth in claim 1, wherein a number of the heating elements and the corresponding casings are carried by a hollow closed body serving as a float, substantially as described.

7 An electric heater as set forth in the preceding claim, provided with a handle and used in conjunction with a switch serving to support the heater when not in use, the circuit being automatically closed when the heater is removed from the switch, substantially as described.

' JOHN ROBERT QUAIN.

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