US1322073A - Method oe forming heater elements eor liquid-heaters - Google Patents

Description

F. J. STUART.

METHOD'OF FORMING HEATER ELEMENTS FOR LIQUID HEATERS.

APPLICATlON FILED AUGLZZ, 1917.

Patented Nov. 18, 1919.

Swuemtoz 3: cf staarzi,

UNITED STATES PATENT OFFICE.

FRANK grosnrn stream, or ST. LOUIS, MISSOURI.

METHOD OF FORMING HEATER ELEMENTS FOR LIQUID-HEATERS.

To all whom it may concern:

Be' it known that I, FRANK J. STUART, a citizen of the United States, residing at St. Louis, State} of Missouri, ha-ve invented certain ,new and useful" Improvements in Methods of- Forming HeaterElements for Liquid Heaters, of which thefollowing is a specification.

This application includes matter divided from my copending' application, I filed *No vember "10, 1916, Serial Number 130,591, and to that 'eXtent is a" continuation of said earl er pplication,

The invention'has for an object to provide a suitable electrical heater unit adapted to use in liquid heating apparatus. It is a particular aim of the invention togive an efficient and durable constni'ctionof heating coil, whereby the" complete" device may be produced at a very low cost. 'To'this end, a special method of buildingupand form ng the heater coil has been evolved, as-well'as-an especially desirable mountingfor such a coil by which it is adapted'to be introduced nto a receptacle or chamber in'which liquid 18 to be heated.

Additional objects, advantages, and features of invention will'appear from the-disclosure of one embodiment"oftheinvehtion as hereinafter described-and shownin the drawings, wherein,--"' 'i Figure 1 isanelevation of a coil asap.- plied to a heater for motor vehicle rad ators,-

Fig. 2 is a similar viewrof -the appliance, with a different mounting,

" Fig. 3 is a detail of the'mounting of the appliance, I

Fig.- 4 is a detail of the structure of the coil 1 Fig. 5is a detail'ofa bushingelementf Fig. 6 is a detail ofa terminal connection and mounting for the coil 'Figfi7 isa vertical sectional view of a modification of the appliance. I 1

There is illustrated in-dotted lines acylindrical heater casing 16, having large screw threads 17- throughout its length, this casing being open at its lower sideyand havingan integral annular 'fcr'own piece 18 at the upper end," from which :thereextendsdownwardly a drain tube 19 of-cylindrical form which may be located slightly eccentric to the casing, and project a distance below the casing proper. The lower end of the casing is closed by a plate 20, ei'igaged slidably over the projecting lower end of the tube 19, and held snugly against the end of the casing Specification of Letters Patent.

Patented Nov. 18, 1919.

Application filed August 22, 1917. Serial No. 187,708. 7

16 by means of a nut 21 secured on to the lower end of the tube 19. Fitted in the lower end of the tube there is an ordinary drain cock 22. Between the plate 20 and the casing a suitable heat insulating body 23 may be disposed. Mounted upon the plate 20 there is a helical heating coil 24', having the lead wires 25 extended therefrom laterally through opposite sides of the casing as indicated in Fig. 2, or extended down wardlythrough the plate as shown in Fig. 1. Theheatin'gcoil of Fig. 1. comprises a core element 26 of sufiicient rigidity to hold the coil in propel-form and prevent undue distortion or damage thereto by vibration during the 'first stages of manufacture, and to aflord a good footing or base for its mounting, the core in the present instance comprisinga heavy steel wire, around which a covering of suitable non-conducting and heatresisting material 27 such as asbestos is engaged, upon which in turn the heating coil proper is wound. The heating coil 33 stops short of the endsof the wire 26 and its covering 27, and the ends of the support ing wire 26 and covering are bent into suitable eyes at 28, and secured to the plate 20 by means of screws 29? The lead wires 30 are engaged in suitable bushings 31, where they are led in through the casing or the plate 20, as the case may be, and in Fig. 5 there is shown a form of bushing the inner part of which is longitudinally slitted in a number of places circumferentiallyspaced, and the inner part of the bushing tapered and threaded, so that whenscrewed into the threaded opening in the plate 20the sides of the'bushin'g will be compressed so as to grip the wire 30 or its insulation, and hold it securely against loose movement. The Wire 30 is connected to the end of the heating coil33 in any customary manner, within the casing.

In the production of the coil, suitable lengths of Wire 26 and its acketing are pro vided, upon which the heating wire 33 is wound. The ends of the wire 33 being temporarily secured after winding, the heating element is then bent into the desired shape, as shown, for instance, at 36 in Figs. 1 and 2. After being bent to this shape, the complete coil is then dipped in a paste of a suitable clay, cement, 'or other material, of such consistency that when the surplus is shaken or drained off, a suitable coating is left upon the coil, this paste material being of a suitable character to become hardened under the effect of heat, or otherwise, and being a non-conductor of electricity, but'of a character to readily radiate and conduct heat. Potters clay has been used for the purpose with satisfactory results. This has the effect of further stifl'ening and supporting the upper parts of the element.

In assembling the device, in the form shown in Fig. 1, the coil after being dipped or otherwise coated with the stiffening insulation, is first mounted upon the insulating body 23 and the plate -20, the lead wires 30 then extended through the bushings in the plate 20, and connected to the ends of the heating coil wire, after which the plate is adjusted in position on the bottom of the casing .16, and secured by the nut 21. The cook 22 may then be put in place and the device is'ready for attachment to the radiator. In the form shown in Fig. 1, the complete coil and its connections may be assembled on the plate 20, before introduction into the casing 16, as will be readily apparent. The coil 36 is formed with an upstanding portion 35 from the upper end of which the coil is continued downwardly, the part 35 being located closely within the coil 36at one side.

A further simple construction for the device which may be considered preferable is shown in Fig. *2, wherein there is shown a cylindrical casing element 40. Within the element 40, a coil 44 is mounted, which in the present instance need not have the central core wire 26 before mentioned if undesired, the coil being supported by means of a pin 45, driven through suitable diametrically alined openings in the upper part of the element 40, and engaging under one of the upper helices of the coil 14. The ends of the resistance wire 46 of the coil are extended through suitable openings at opposite sides of the tube, at its lower end, in which bushings 47 may be fitted similar to the bushing 31, if desired. The wires 46 may be connected in any desired manner with an energizing circuit as will be readily understood.

Various methods for mounting the'coil in a liquid container may be employed,'in addition to those before described, and it may be found preferable to mount the coil upon its supportand 'make the connections between the heating coil and insulated binding posts before dipping the appliance, and then dipping the mounted coil so that its base portion and the terminal ends of the heating coil proper will all be covered by the coating of outer insulating material, the subsequent hardening of which will protect all parts of the device from contact with the liquid which may circulate about the coil. An example of this method isillustrated in Fig. (3, wherein a coil is mounted upon a body 50, which may comprise the wall of a receptacle or a suitable base plate separate therefrom, the terminal portion of the supporting element in the coil being formed in the same manner as shown in Fig. l, and as previously described. The securing bolts 51, however, are insulated from the plate 0 in a suitable manner, and the terminal portions of the core element of the coil are also insulated therefrom by means of a sheet of insulating material The terminals of the heating wire are engaged under the heads of the bolts 51, suitable washers 53 being disposed under the heads to clamp the insulating material around the stiffening wire of the coil. After being secured in this way, either temporarily or permanently, the coil is dipped so that the exterior coating of insulating material 54 will cover the bolt heads and the terminal ends of the heating wire, as well as the sheet 52 of insulating material. The sheet may be of porcelain or indi'a rubber, as found most desirable.

The body 50 is formed with holes larger than the bolts 51, so that the latter may not touch the body 50, and the bolts are held centered in the openings byv means of simple bushings 55,.nuts 56 being engaged on the outer ends of the bolts to hold them in place, Binding nuts 5.7 may also be engaged upon the outer ends of the bolts for connecting suitable wires thereto.

If desired, the plate 50 may have a drain cock 58 fitted thereto as shown in Fig. 7, and be secured to the bottom of a casing 59 of considerably larger diameter, having a small threaded nipple at the upper end adapted to be screwed into the usual small outlet opening of a radiator, in place of the usual drain cock.

\Vhat is claimed is:

The method of forming a heating coil or resistance element consisting in winding upon a comparatively rigid wire jacketed with non-conducting material, a suitable resistance wire to form a heating coil upon the said jacket, the winding stopping short of the end of said jacket and inclosed wire, then bending the assembly described into the shape finally desired, and dipping the parts having said winding thereon in a thin paste of a material adapted to harden by the ac- 'tion of heat or otherwise,.and which is a good conductor of heat;-

In testimony whereof I have affixed my signature in presence of two witnesses.

FRANK Jos -PH STUART.

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