US 2923797 A
Description (OCR text may contain errors)
Feb. 2, 1 960 F. E. THELEN 2,923,797 HIGH TEMPERATURE CUT-OFF SWITCH AND IMMERSED ROD ASSEMBLY FOR HOT WATER GENERATING TANKS Filed July 1, 1957 VALVE. ME HANiM HIGH TEMPERATURE CUT-OFF SWITCH AND IM- MERSED ROD ASSEMBLY FOR HOT WATER GENERATING TANKS Floyd E. Thelen, Atchison, Kans., assignor to Luxra Company, Atchison, Kans., a corporation of Kansas Application July 1, 1957, Serial No. 669,229 3 Claims. (Cl. 200-137) This invention relates to a high temperature cut-ofl for hot water heaters and more particularly to electrical cutoffs therefor for attachment to magnesium rod fittings therefor, although it may be advantageously employed in connection with other fittings on hot water heaters.
tain the water temperature at safe maximum limits under all conditions.
Most every modern quality hot water heater is provided with a safety shut-ofi to insure the safe operation thereof should the gas pilot fail or the burner shut off or terminate the generation of hot water after reaching a pre-set temperature limit. Then, too, quality instantaneous hot water heaters are now equipped with magnesium rods to minimize the corrosion of the water tank and to add to the life thereof. This rod conducts the heat of the water very rapidly to the body of the tank, and particularly to the body top end thereof to provide the most effective temperature indicator response area thereof.
In ':'order to provide the most efiective temperature control of hot water generating tank heaters through the medium of a single opening therein, an improved simple fitting has been provided to extend through the customary and standard threaded opening in the tank for mounting of a temperature responsive switch at one end and a magnesium rod at the other end. This is effected with a double threaded pipe fitting having an exteriorly threaded tank engaging portion and an internally threaded end to threadedly receive and connect an element thereto such as an internally suspended magnesium rod in water immersed relation to a hot water generating tank. The exterior surface of the fitting is provided with a simple and eifective thermally responsive electric switch mounted thereon to quickly respond to temperature changes in the water to insure eflicient operation.
One object of the present invention is to provide a simple fitting having threaded portions for mounting of exteriorly and interiorly disposed operating elements in relation to a hot water generating tank.
Another object is to provide a cylindrical fitting with intermediate threads for mounting two operating elements in relation to a threaded tank opening serving as a support therefor.
Still another object is to provide a hot water generating tank with an externally threaded fitting having a threaded portion for connection thereto and another threaded inside end for mounting of elements in water immersed relation with a tank for mounting of a thermally responsive electric switch in efiective thermal communication with the water therein.
A further object is to provide a fitting having an ex- United States Pat ent O ternally threaded portion to serve as an exterior mount for a thermally responsive switch and an internally threaded end portion for suspended mounting of a magnesium rod in effective heat conducting communication between the water in the tank and the thermally responsive electric switch.
Still a further object is to provide a unitary fitting having a series of multiple threads to serve as a dual mount for a thremally responsive electric switch and a magnesium rod in immersed water relation to a hot water generating tank whereby the temperature of the contents is in communicating conductance with both the rod and switch.
Other objects and advantages will appear from a description of an illustrated embodiment of the present invention.
In the drawing:
Figure 1 is a front view in elevation of a hot water generating tank of the instantaneous type provided with a tank mount for an electric thermally responsive switch and a magnesium rod suspending portion embodying features of the present inventon, parts thereof being broken away and shown in section to clarify the showing.
Figure 2 is a sectional view in elevation of the dual fitting and mount taken substantially along line II-II of Figure 1.
Figure 3 is a plan view of the switch and mount viewed substantially from line III-III of Figure 2.
Figure 4 is a schematic wiring diagram showing the electrical relationship between the various elements for controlling the temperature of the water in the tank.
The structure selected for illustration is not intended to serve as a limitation upon the scope or teachings of the invention, but is merely illustrative thereof. There .may be considerable variations and adaptations of all or part of the teachings depending upon the dictates of commercial practice. The present embodiment comprises a cylindrical upright tank 10 of galvanized steel construction or of the glass-lined variety which is disposed within a correspondingly shaped and somewhat enlarged jacket or casing 11 having insulation 12 packed therebetween in the chamber defined by the vertical walls and tops of the respective tank and jacket 10-11. The
Y tank body 10 has a convex integral top 13 and a concave bottom 14.
The tank 10 has its slightly concave bottom 14 disposed immediately above a standard burner such as a gas burner 15 which communicates with a gas supply pipe 16 provided with an adjustable air regulating shutter of the conventional type (not shown). A closure 17 is provided in the tank jacket or casing 11 immediately below the burner 15 for access thereto and to a pilot light (not shown) for hand lighting with a match. A transparent sight 18 may be provided in the tank casing 11 to enable viewing the flame produced by the burner 15 while in operation to enable adjustment by regulating the air intake shutters (not shown) to the burner 15.
A cold water inlet pipe 19 threadedly connects with the top and extends downwardly for a considerable distance as at 20 for communication with the bottom interior region of the hot water generating tank 10. A hot water discharge pipe 22 connects with the top of the tank 10 as at 23 for supplying the hot water to the pipe line. A fusible plug 23 within the relief valve 24 connects with the top of the tank 10 as at 25, and normally precludes the flow of water through an overflow pipe 26-27 connected thereto for discharge to a sewer or other drainage point. The heated water 28 within the tank 10 communicates with the fusible plug 23 which will melt and open the passage to the overflow pipe 26--27 in the 3 a, teventgthewater lzssshonld rise to a dangeroustemperttiture.
30 provided centrally within the top 13 of the tank 10, areceives .an v externally threaded mounting vfitting D31, 1 in this tinstance havingra reduced exteriorlytthreaded shank :31. terminating in an enlarged hexagonal-flat,surfacehead 1 32: providing for the application of a'wrenchforrtightent ing engagement with the :tank aperture 29' by means of the threaded shank 31. The externally threaded shank .31ris,provided with an axial bore SS-which is interiorly threaded to receive the'upperthreaded extremity 34 of -an elongatedrrnagnesium rod-35 that extends downwardly orinwardly belowthetanktop 12 for immersiontinto -thewater 28 forthegreater partof the tank 10.
g To this end; the magnesium rod.35 has.its. externally threaded upper extremity 34 complemental to theinternal .boresthreadt33 ,of-the-tshankfil to enable the threaded engagement of ,thenmagnesium rod 35 therewith for. in-' ternal suspension for most of the water depth .within. the tank 10. It will be apparent, therefore that the elongated magnesium-rod35 will conduct the most elevated temperature of theuppenstrataof'thewater 28 to the .body .of the fitting32, and .the enlarged surface thereof insidethe tank housing or jacket 12 and underneath the ...top insulationlZ will afford the efiective support of a ..thermostatic bellows typeswitch body 36, in this. instance of circular shallow configuration.
The switch body 36 .is attached to the uppersurface -of the magnesiumrod fitting 32by means. of suitable fasteners 37 which extend through casing earsl38. A ,convexlyleshaped thermallytresponsive bottorn.39 comprisingpart of the switcheasing, touches theffitting3'2 ,and becomesdistorted upwardly when the water temperal' .ture reachesua maximum of 205 degrees'Fahrenheit.which is the safety-limitttherefor. In sotdoing, its insulator vinterior lining 40; touches themetal terminal bridging .element'41. toelevate it into contact with the normally closed--terrninals-4243 connected in series with the vlead wires 4445 (Figure 4) which are in circuit with a thermocouple 46 and a solenoidtoperated thermostatic valve,mechanism-47. The switch 41 opensthe circuit at '205 Fahrenheit to shut off the gas by de-energizing a .solenoid actuated thermostatically responsive valve in a manner well known inthe art.
, While I have illustrated and described a preferred embodiment of this-invention, it must beunderstood that .the invention is.capable of considerable variation and modification vwithout departing from the spirit of 'the invention. '1, therefore, do not wish to be limited to the ,.precise details .of constructionset forth, buttdesire to A central threaded aperture 29 in an upraised boss availmyself or such variations and modifications-weenie within the scope ot'the appended claims.
I claim: 1. -An integral unit fitting for an instantaneous hot water heater tank, comprising a plug member for detachable association with the top end wall of said tank for communication w-ith-the-sinterior thereof, said plug member having a fiat surface exterior for mounting of a heat responsive electrical' switch thereon in conductive relation therewith, a reduced threaded ,shank:i.depending from said flat surface plug member for engagement with a" complemental opening in the 1 topuend wall ofithe' hot water :heater tank, :there :being a bore .in said threaded shankrnemberclosedbysaid plug memberandopen at its bottom en'dforcommunication with the tank interior when in assemblediengagementtherewith, an elongated magnesium rod in anchored attachment at one end thereof with the bore in said threaded shank member of the plug member. for v suspended, support thereof Within the ,hotwatertheater tank'for ,substantiallytthe internal length ,thereof, and-athermally responsive xelectrical switch tmountedionvthetopflat surface ofsaidzplug member, saidiswitchsadaptedto be connected electrically in circuit iwith-anautomaticfuel shut-off valve controlling the fuel 25.supply to the burnerof the tank, said switch being in direct heatconductive connection with said magnesium rod 5 for effectively rendering said thermally responsive ..switchtin anopeniorclosed position depending uponzthe -ternperature ofnthe rod, whereby-an efiective electrical safety shut-off is -provided :asta part .of an integral unit ,fitting. V
2. The combination set forth in claim .1.wherein:1the electrically."responsive zshut-otf switch, is of the. flat; heat .responsive ..bellows type for .mechanically closing or maintaining theswitch open depending upon .the tempera- ,ture ofsaid magnesium-rod. i v
. .3. The, combination set forth .invclaim 2 wherein the thermally: responsive electrical switch, flat surface ,-plug ..member, andmagnesium rod-are fixedly and permanently -.attacheduintlongitudinal axial alignment relat-ive tothe ..latter .for assembly, as a unit with said tank.
RefereucesCited inthe' file of thispatent UNITED STATES PATENTS