US 1992635 A
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Feb.- 26, 1935. H. RITTERHOFF ET AL 'THERMO ELECTRICAL HEATING ELEMENT Filed Aug. 26, 1933 Patented Feb. 26, 1935 v 1,992,635
UNITED STATES PATENT OFFICE THERMO -ELECTRICAL HEATING ELEMENT Harry Bitter-hon, Homer Cessna, and Fred E.
Reinhold, Los Angeles, Calif., assignors of onefourth to Alva J. Calhoun, Los Angeles, Calif.
Application August 26, 1933, Serial No. 686,936
' 1 Claim. (Cl. 219-40) This invention relates to electric water heatsure heador plug 26, said plug having a shoulers, and more particularly to a portable applider 2'7 that engages the bottom faces of the tube ance of the character that is adapted to be imand sleeve. The sleeve 13 and rod 24 serve as mersed in the water within a container for raispositive and negative electrodes.
.5 ing the temperature of the same. Mounted in a recess formed in the body 10 is An object of the invention is to provide a heater a connector post 28 having a depending leg 29 of the character stated in which the water itself that is embedded in said body, the leg 29and acts as a conductor, and provided with adjustbody being drilled and tapped for the reception ing means whereby the temperature of the water of an adjustable screw contact 30, the head of may be regulated at will. which is embedded in a knob or handle 31 formed 10 Another object is to provide an electric water of electrical insulating material for turning the heating appliance of simple construction, which same. will occupy but little space and may be quickly Secured to the block 23 is'a conventional therapplied to the neck of a rubber water bottle or mostatic device 32 consisting of a pair of heat other container. responsive elements 33, each of which have dif- 15 A further object is to provide a portable elecierent coeflicients of expansion, said elements tric water heater of the immersion type which being secured together at their upper ends. The may be cheaply produced, easy to handle, and thermostat normally engages the point 34 of the which will very efficiently perform its intended screw contact, i.- e. when the parts are cold or function. contracted. D
Other objects and advantages will be apparent The thermostat also serves as an electrical confrom' the following description, reference being ductor between the screw contact 30 and elechad to the accompanying drawing, in-which: trode 24 in addition to making and breaking the Fig. 1 is a side elevation of the improved eleccircuit therethrough. trical fluid heating appliance. Stamped or otherwise formed on the outer face 25 Fig. 2 is an enlarged longitudinal section taken of the body 10 is an indicating dial 35, the indices on line 22 of Fig. 1. 36 of which register with a single mark 37 on Fig. 3 is a transverse section taken on line 3-3 the knob 31. The dial and mark serve to inof Fig. 2. dicate the desired degree of temperature of the Fig. 4 is a transverse section taken on line 44 water heated by the device, i. e. by turning the 30 of Fig. 2. knob to the right or left the time required to Referring more specifically to the drawing, 10 break the circuit between the screw contact may designates the body of the improved heating apbe varied. pliance, the body being formed of electrical in- Formed on the knob is a lug 38 and projecting sulating material such ashard rubber or bakelite. from the body is a stop pin 39 that serves to 35 The body is preferably of cylindrical shape in limit turning movement of said knob, also to cross section and has formed thereon a portion prevent the screw'from being completely turned that is externally screw threaded as indicated at out of engagement with the thermostat. 11 for connection with the internally threaded secured to the upper end of the sleeve 13 and 40 neck of a fluid container such as a hot water extending through an opening formed in the 40 bottle indicated in dotted lines in Fi 1. body is a conductor 40, the space around the con- Mounted on the lower end of the body and ductor being filled with suitable selling substance, engaging a. reduced diameter portion formed such as a rubber cement, indicated at 41 after thereon below the threads is a metal tube 13 assembling in order to prevent escape of steam having a plurality of openings 14 therein that or water through said space into the interior 45 register with opening 15 in a sleeveor casing 16 of the body when the device is being used. formed of insulating material, the sleeve being Mounted in a recess formed in the body at a provided in order that the heater may be hanpoint opposite to that of post 28 is a post 42 dled without danger of receiving a' shock when having a leg 43 embedded in the body, and screw it is connected with a source of current. threaded in said leg is a contact screw 44 that 50 Mounted inarecess 21 that communicates with engages the free end of a thermostat 45, the the interior 22 of the body is a hexagonal nut opposite end of which is secured to the conductor or block 23 and screw threaded in said nut is 40. s a rod 24, the opposite end of which is screw This thermostat is of the same construction and threadedly connected as indicated at 25 to a clois set to break the circuit at a higher temperaback of the adjusting screw 44 being filled or plugged up as indicated at 46 after adjusting the same.
Mounted on the upper end of the body 10 is a closure cap 50 formed of insulating material, said cap being secured to the body by screws or the like 51 and having openings 52 formed therein for the reception'of the connector posts 28' and 42, the side face of the cap being preferably knurled as indicated at 53 to facilitate handling of the appliance.
In use, the heating appliance is adapted to be connected to a usual plug of a socket secured to a flexible conduit, not shown. This is done by inserting the posts 28 and 42 through the slots formed therein.
The knob 31 is then adjusted to the temperature desired (by reference to the dial 36) and the appliance screwed into the neck of a container filled with liquid to be heated, whereupon the space within the tube becomes filled through the openings 14 and 15.
. It will be noted that prior to immersion of the appliance in liquid no electric circuit has been established although the above connections have been made.
As soon as the space within the tube becomes filled. or partially so, a circuit is established through the liquid which then acts as a resistance causing said tube and bar to become heated, resulting in raising the temperature of the liquid.
As the temperature of the liquid rises it acts upon the heat responsive elements 33 of the thermostat 32 (through the rod 24 and nut 23) causing one of them to expand at a greater rate than the other, the action of which causes the same to gradually straighten and at the same time move away from the point 34 of the contact screw 30 until the circuit is finally broken at this point.
The circuit then remains open or broken until ture than that of the thermostat 32, the space the liquid cools off or reaches a temperature slightly below that of its high point, whereupon the circuit is reestablished.
In the event that the thermostat 32 should fail to function the thermostat will break the circuit and thereby prevent overheating of the water in the container.
It will be understood that the appliance may be also advantageously employed to heat or boil water in open containers.
An electric water heater of the character described comprising a hollow body formed of electrical insulating material having an externally screw threaded portion for connection with the neck of a liquid container, a perforated tubular member secured to said hollow body and forming one electrode, a metal block mounted in a recess formed in said body, a rod secured to said block and extending through said perforated tubular member and forming the other electrode, an adjustable screw contact threaded in said body and extending into its interior, a thermostat consisting of a pair of heat responsive elements having differential coefficients of expansion secured at one end to said block with their opposite ends secured together and normally engaging the end of said adjustable screw contact, a connector post mounted on and having a portion embedded in said body and threadedly engaging said adjustable screw contact, a second connector post mounted on and having a portion embedded in said body, a second screw contact threaded in said body and projecting into its interior and a second thermostat of the same construction as said first mentioned thermostat secured at one end to said perforated tubular member and normally engaging said second screw contact for the purpose set forth.
HOMER CESSNA. FRED E. REINHOLD.