LIQUID HEATING VESSEL

• US 3,678,246 A
• Filed: 06/24/1970
• Issued: 07/18/1972
• Est. Priority Date: 06/24/1970
• Status: Expired due to Term

• Current Assignee: Donald L. Blachly, Jack E. Weidner
• Original Assignee: Donald L. Blachly, Jack E. Weidner
• Inventors: Blachly, Donald L., Weidner, Jack E.
• Primary Examiner(s): Mayewsky, Volodymyr Y.
• Application Number:
  US05/048,978
• Time in Patent Office: 755 Days
• Field of Search: 219/436-439,441-442,430-435,316,318,335-336 99/280-282
• US Class Current: 219/437
• CPC Class Codes: A47J 27/21058 Control devices to avoid overheating, i.e. "dry" boiling, or to detect boiling of the water A47J27/21158 takes precedence

Abstract

An appliance for heating a quantity of liquid in a molded plastic vessel with a heating element cast into a lug which extends upwardly into the water containing portion of the vessel. The energization of the heating element is controlled by a thermostat positioned at the bottom of the vessel in good heat transfer relation with the vessel contents.

Claims

1. A liquid heating appliance comprising a molded integral plastic vessel having side walls, a bottom wall and an open top, an electrical heater mounted on said bottom wall and supported at least partially within said vessel and extending through an opening provided in said bottom wall, said heater having a body portion positioned within said vessel and a mounting portion of reduced section extending through said opening and extending substantially below said bottom wall, said heater comprising a casting within which is enclosed a sheathed heating element having at least one loop in said body portion and spaced end portions extending through said mounting portion, coiled resistance wire received within said loop and elongated low resistance terminal members connected to said resistance wire and positioned in said end portions, said low resistance terminal members extending substantially through said mounting portion to minimize the heat delivered to said mounting portion, said terminal members being insulated from and extending outwardly of said mounting portion for connection to a source of electrical power, means supporting said vessel in an upright position and enclosing said terminal members.

2. A liquid heating appliance comprising a molded integral plaStic vessel having side walls, a bottom wall and an open top, an electrical heater supported at least partially within said vessel and extending through an opening provided in said bottom wall, said heater having a body portion positioned within said vessel and a mounting portion of reduced section extending through said opening, said heater comprising a casting within which is enclosed a sheathed heating element having at least one loop in said body portion and spaced end portions extending through said mounting portion, coiled resistance wire received within said loop and elongated low resistance terminal members connected to said resistance wire and positioned in said end portions, said terminal members being insulated from and extending outwardly of said mounting portion for connection to a source of electrical power, said heater is connected in circuit with a control thermostat and a safety thermostat, said control thermostat being mounted on said plastic bottom wall in good heat transfer relation to the liquid contents of said vessel, means supporting said vessel in an upright position and enclosing said terminal members.

3. The liquid heating appliance of claim 2 wherein said safety thermostat is mounted on said mounting portion of said casting to respond to overheating of said heater when said vessel is empty.

4. A liquid heating appliance comprising a molded integral plastic vessel having side walls, a bottom wall and an open top, an electrical heater supported at least partially within said vessel and extending through an opening provided in said bottom wall, said heater having a body portion positioned within said vessel and a mounting portion of reduced section extending through said opening, said heater comprising a casting within which is enclosed a sheathed heating element having at least one loop in said body portion and spaced end portions extending through said mounting portion, coiled resistance wire received within said loop and elongated low resistance terminal members connected to said resistance wire and positioned in said end portions, said terminal members being insulated from and extending outwardly of said mounting portion for connection to a source of electrical power, said heater is connected in circuit with a control thermostat and a safety thermostat, said control thermostat being mounted on said plastic bottom wall and being set to open the heater circuit when the liquid in the vessel is close to the boiling point of water, said safety thermostat being supported on said heater casting and being set to open said heater circuit at a substantially higher temperature than said control thermostat but below the temperature at which said plastic would be damaged, means supporting said vessel in an upright position and enclosing said terminal members.

5. The liquid heating appliance of claim 4 wherein said control thermostat and said safety thermostat are clamped against said bottom wall and heater respectively by a bracket which extends between said thermostats and which is secured to said heater intermediate said thermostats.

6. A liquid heating appliance comprising a molded integral plastic vessel having side walls, a bottom wall and an open top, an electrical heater supported at least partially within said vessel and extending through an opening provided in said bottom wall, said heater having a body portion positioned within said vessel and a mounting portion of reduced section extending through said opening, said heater comprising a casting within which is enclosed a sheathed heating element having at least one loop in said body portion and spaced end portions extending through said mounting portion, said vessel being supported by an annular plastic base, said base having a stepped edge at the top thereof which engages a complimentary stepped edge at the bottom of said vessel, said vessel bottom wall and said base forming a base compartment which is closed at the bottom by a plastic closure plate, assembly means extending through said plate and saId base into threaded engagement with said vessel.

7. The heating appliance of claim 6 including a signal light in said base compartment connected in circuit with said heater, a recessed wall portion on said base adjacent said light being sufficiently thin so that said light may be observed through the wall of said base when it is illuminated.

8. The heating appliance of claim 7 wherein said heater is connected in circuit with a control thermostat, said thermostat being mounted on the underside of said bottom wall, said bottom wall adjacent to said thermostat being thin to provide good heat transfer between said thermostat and the contents of said vessel.

9. The heating appliance of claim 1 wherein said body of said casting is cylindrical in shape and encloses two circular connected loops of sheathed element positioned one above the other, said mounting portion being of reduced diameter compared to said body portion and being threaded to receive an assembly nut which tightens against the bottom wall of said vessel.

10. Water heating appliance comprising a one piece integral plastic molded cup shaped vessel having cylindrical side walls and a bottom wall, an electrical heater assembly including a sheathed element cast into a heat transfer mass, said mass having a body portion in said vessel and a mounting portion extending through an opening in said bottom wall, said body portion enclosing a portion of said element including a coiled resistance wire and said mounting portion enclosing a portion of the element having a low resistance terminal connection, a contact thermostat mounted on the plastic bottom wall of said vessel in good heat transfer relation to the liquid in said vessel to sense its temperature, a safety thermostat supported in good heat transfer relation to said mounting portion, said control thermostat and said safety thermostat being connected in series with said sheathed heating element, means supporting said vessel in an upright position and enclosing said terminal connection.

11. The heating appliance of claim 10 wherein said bottom wall is sealed to said heater assembly around said opening, said bottom wall being recessed to provide an area of reduced thickness between said control thermostat and the center of said vessel.

12. The heating appliance of claim 10 including an elongated retaining bracket secured intermediate its ends to said mounting portion of said heater assembly, one end of said bracket engaging said control thermostat and urging it into engagement with said vessel and the other end engaging said safety thermostat and urging it into engagement with said mounting portion.

13. The heating appliance of claim 12 wherein said sheathed element includes spaced parallel ends which extend downwardly from said mounting portion, said bracket extending between said parallel ends and being mounted to said heater assembly between said parallel ends, said safety thermostat being received in a downwardly facing recess spaced equidistant from said parallel ends.

14. The water heating appliance of claim 10 wherein said element has at least one loop in said body portion and only low wattage terminal portions extending through said mounting portion.

15. The water heating appliance of claim 10 including a cup-shaped base which abuts the bottom of said vessel to form a closed base compartment having terminal pins extending through a side wall of said base, said sheathed element having its wattage concentrated in said body portion to provide maximum heat transfer to said liquid and minimize heat delivered to said base compartment.