US3766358A - Immersion heater - Google Patents

Immersion heater Download PDF

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Publication number
US3766358A
US3766358A US00248000A US3766358DA US3766358A US 3766358 A US3766358 A US 3766358A US 00248000 A US00248000 A US 00248000A US 3766358D A US3766358D A US 3766358DA US 3766358 A US3766358 A US 3766358A
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Prior art keywords
immersion heater
current
heating element
circuit
heater
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Expired - Lifetime
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US00248000A
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English (en)
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Erb K Gass
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/78—Heating arrangements specially adapted for immersion heating
    • H05B3/80—Portable immersion heaters
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/1906—Control of temperature characterised by the use of electric means using an analogue comparing device
    • G05D23/1909—Control of temperature characterised by the use of electric means using an analogue comparing device whose output amplitude can only take two discrete values
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/1927—Control of temperature characterised by the use of electric means using a plurality of sensors
    • G05D23/1928—Control of temperature characterised by the use of electric means using a plurality of sensors sensing the temperature of one space
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
    • G05D23/24—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor

Definitions

  • the present invention contemplates the provision of an immersion heater which, in addition to incorporating advantageous and versatile temperature controls also provides for an optimum and equal temperature distribution throughout the fluid.
  • the inventive immersion heater operates automatically and, furthermore, does not require servicing during operation.
  • the foregoing object of the present immersion heater is attained by providing, within the ambit of the electrical control current circuit of its heating element, a mixing device for the heated fluid.
  • the immersion heater according to the present invention is formed of a compact constructure and operates essentially uninterruptedly.
  • Another feature of the immersion heater lies in that the mixing device is rigidly fastened to the upper surface of the heating element and preferably is encompassed by a protective arrangement which permits unhindered flow of the fluid therethrough.
  • FIG. 1 illustrates an elevational view of an immersion heater according to the present invention
  • FIG. 2 shows a plan view of the immersion heater of FIG. 1;
  • FIG. 3 shows a sectional view through a drive for a mixing device utilized with a heater according to the present invention
  • FIG. 4 shows a plan view of the drive of FIG. 3
  • FIG. 5 shows an enlarged detailed plan view of a portion of FIG. 3
  • FIG. 6 illustrates a sectional view along line 6-6 in FIG. 5;
  • FIG. 7 shows an enlarged fragmentary sectional view of another embodiment of the arrangement of FIG. 3;
  • FIG. 8 illustrates a schematic view of a further embodiment of a mixing device used with a heater according to the present invention.
  • FIGS. 9 12 illustrate four embodiments of wiring diagrams for an immersion heater according to the present invention.v
  • FIG. 1 illustrates a basic embodiment of the inventive immersion heater wherein a handgrip 1 is connected to a heating element 2 by means of a hollow rod 3 which is bent to provide a suspension arrangement for immersion of the heating element into fluid contained within a vessel.
  • the hollow rod 3 concurrently provides a passageway for the electrical power conduit for heating element 2.
  • Suitable elements constituting the temperature control installation are positioned in handgrip l, the former of which may be formed of a contactless switch. This will effectively eliminate the risk of any sparks igniting flammable fluids or vapors emanating therefrom.
  • the contactless switch incorporates its own electrical control current circuit and a safety switching circuit, which will be described in greater detail herebelow with reference to the circuit diagrams.
  • a rotatable control knob 4 for an adjustable control resistance, a control lamp 5 for the control current circuit, and a control lamp 6 and 22 for a safety switching circuit 21, are each located on the handgrip. Each position of the rotatable knob 4 corresponds to a predetermined desired maximum operating temperature for heating element 2. Upon the operating temperature being attained, the flow of electrical current to heating element 2 is interrupted by means of a temperature sensor 7 which may be, for example, a thermistor. In the event that, through some operative defect, the heating cycle is not terminated, the safety switching circuit is actuated to thereby prevent excessive overheating of the fluid.
  • a mixing device 8 is fastened to the upper surface of heating element 2, and is protected by a protective arrangement 9 so as to provide protection against damage not only during operation of the immersed heater, but also during storage and handling.
  • the protective arrangement 9 may be, as is shown in thedrawings, constructed of four bent wires which extend over the mixing device. However, numerous other constructions readily lend themselves to the formation of the protective arrangement. Thus, for example, a housing of a wide-mesh grillwork may be stapled over the mixing device. In each instance it must, however, be noted that unhindered access of the fluid to the mixing device 8 must be provided by the protective arrangement.
  • the heating element 2 is formed as a heating spiral having the mixing device 8 centrally positioned thereon.
  • FIG. 3 of the drawing The drive or actuator and detailed construction of the mixing device 8 is illustrated in FIG. 3 of the drawing.
  • a preferably circular plate 8' may be utilized which is reciprocable in an axial direction. This construction eliminates the need for the commonly used rotating elements in mixing devices, which must be constantly serviced and which are subject to a high degree of wear.
  • the drive or actuator for plate 8' operates pursuant to electromagnetic principles and is sealed within a housing 10.
  • the main element of the drive consists of an induction coil 11 which is provided with electrical current through an electrical conduit 11'. Accordingly, the coil 11 may be connected, for example, in series with theheating coils, and with the electrical control current circuit of the immersion heater. In this instance, upon a maximum predetermined temperature being attained, the mixing sequence is terminated concurrently with the flow of electric current to the heat coils of the heating element.
  • the winding of the inductioncoil 11 must be made in conformance with the current intensity required by the heating coils of the immersion heater, and is thereby formed of heavy copper wire, whereas in the second instance, the winding isformed pursuant to the supply voltage and is constituted of thin copper wire having a corresponding larger number of windings.
  • A- stationaryiron core 12 is located within housing 10, and is fastened to induction coil 11; with coil 12 having a portion 12" extending over coil 11, as shown in FIG. 4, so as to provide a guide for a movable iron core 13 which is rigidly connected to plate 8.
  • Plate 8' is connected wtih a return motion element 14.
  • the latter may take the form of a membrane 14' constituted of corrugated sheet metal, which concurrently forms the cover for housing 10.
  • the movable iron core 13 is'fastened to the inner wall surface of membrane 14' and serves concurrently as support member for the plate 8'.
  • the electrical conduits 11' extend into housing through connecting sleeve 10 and are sealed in the housing so as to permit the latter to protect the drive for the mixing device from corrosion and dirt.
  • the basic mixing device in effect, plate 8, is provided with nozzles 15 extending in the direction of its reciprocating movement and parallel to the axis thereof, the nozzles being spaced about the entire surface of plate 8.
  • the nozzles 15 in plate 8' may have the form of concentric, ring-shaped rows of apertures, or may be formed as axially widening tapered bores in FIG. 6, or centrally narrowed bores as shown in FIG. 7.
  • the construction according to FIG. 6 the
  • nozzles 15 may have their enlarged openings either upwardly or downwardly directed.
  • the operation of the mixing device is as follows:
  • the movable iron core 13 Upon conduction of an alternating current through the copper windings of induction coil 11, the movable iron core 13 is axially displaced in the direction of stationary iron core 12.
  • the membrane 14 and plate 8' which are rigidly fastened thereto, are correspondingly axially displaced.
  • the membrane 14, and concurrently plate 8' and iron core 13 are snapped-back into the initial position thereof. This process is repeated in correspondence with the frequency of the current, for example at 50 Hertz, 50 times each second.
  • a secondary advantageous mixing or agitating effect is provided through the nozzles 15 of plate 8'. ln this'instance, in view of the funnel-shaped nozzles 15 the fluid is always recaptured and forced through the nozzles.
  • two or more mixing plates 8 may be combined for actuation by a single drive.
  • FIG. 9 of the drawing A simple switching circuit for the inventive immersion heater is disclosed in FIG. 9 of the drawing.
  • the current flowsthrough resistances 16, which also form current limiters, toward trigger diode 17.
  • the trigger diode with the aid of condensators l8, switches through and concurrently ignites alternating current thyristor 19.
  • the heating element 2 is heated and also, through the fluid, contact thermometers 7 and 7' which serve as temperature sensors.
  • the thermometer 7 is located in a safety switching circuit 21 shown in chain-dotted lines in the circuit diagram.
  • the actuating temperature of the safety switching circuit is somewhat higher thanthat of the thermometer 7 of the control current circuit.
  • thyristor 19 prevents the flow of current through the heating element, thereby interrupting the further generation of heat, and concurrently turns off control lamp 5.
  • thermometer 7 Inthe event of a defect occuring, for example a break in thermometer 7, which would prevent the shutting-off the heat upon reaching the required maximum operating temperature, the temperature at first rises to the temperature designated at contact thermometer 7'.
  • contact 20 closes and the current thereby becomes insufficient to switch trigger diode 17, thusly interrupting the heating sequence.
  • the safety switching circuit 21 is actuated.
  • thyristor 23 is triggered by glow tube 22.
  • the resistance 24 warms itself, and wire 25 as a segment of the current supply conduit which extends across resistance 24, thereby melting the wire at a predetermined maximum temperature to thereby terminate the current supply.
  • wire 25 is adapted to melt upon experiencing an excessive ambient temperature.
  • the melting wire 25 should be formed of an alloy having a low melting point, and may be commercially obtained for different heater temperature requirements. The wire may be readily introduced through a suitable aperture in resistance 24-.
  • the induction coil 11 is directly connected to the electrical circuit for the mixing device. As previously mentioned, this requires numerous windings formed of thin wire and is operative independently of the operating temperature for the heater.
  • FIG. 10 Another advantageous circuit is disclosed in FIG. 10, illustrating essentially only the control current circuit.
  • the induction coil 11 may be connected to the control current circuit 21 of the induction heater, and particularly in series with the electrical winding of heatingelement 2.
  • the coil 1 l is designed in accordance with the required current intensities for the immersion heater, and is composed of a lesser number of windings of relatively thicker copper wire. The mixing or agitating process is, in this instance, terminated upon the heating coils reaching their required operating temperature concurrent with the shutting-off of the current supply.
  • a thermistor formed of, for example, an NTC-resistance may be employed as temperature sensor 7, so as to render the immersion heater easier to manipulate.
  • the voltage is reduced by means of a voltage divider 28, which is constructed so that no internal heating of the NTC-resistance 7 takes place.
  • a corresponding RC- element 30 which is formed of one or more resistances 31 and at least one condensator 32, the operative efficiency may be raised to 85 percent and up to a maximum of 95 percent. Furthermore, the resistances 31 provide for a desirable decrease in the circuit voltage thereby reducing the load on thermistor 7 and providing protection for triggers l7 and 22. These latter may only be actuated by means of relatively low current intensities.
  • transmission rectifying members which generally consist of a transmission rectifying valve and condensators. These valves are, however, extremely large, and cannot be practically incorporated in the gripping device for the immersion heater.
  • the schematic also includes a safety switching circuit 21.
  • a thermistor is utilized as a second temperature sensor '7, having a control resistance 33 together with a potentiometer 29 for the control current circuit, mounted on a common axis therewith, so as to form a tandem-potentiometer 34.
  • the temperature sensor 7 and the control resistance 33 must be so coordinated with each other, to prevent the premature actuation of the safety switching circuit.
  • the trigger diode 35 which is utilized in safety switching circuit 21, and concurrently operative trigger diode 26 and thyristor 27 provided in the control current circuit, the flow of current in only one direction, and similarly does thyristor 36.
  • Trigger diode l7 and alternating current thyristor l9 permit the flow of current in both directions. Consequently, a Zener diode 37 is required for the circuit, in accordance with FIG. 11, which shunts-off the negative voltage and concurrently provides for the stabilization of the control voltage.
  • suitable voltage reference tubes, Zener reference diodes and the like may be employed in addition to Zener diode 37. This becomes necessary when it is desired to obtain temperatures in excess of C, since at such higher temperatures the resistance changes of thermistors 7, and 7' are lessened, whereby the voltage deviations result in large temperature deviations.
  • a high-speed safety installation 38 may be provided, which is adapted to cause the short-circuiting of the heating element.
  • thyristors only are utilized, it becomes advantageous to incorporate excess voltage shunts, for example, a transmission conduit 39.
  • the alternating current thyristors Triacs
  • Triacs are designed so that upon excess voltages being sensed these are switched through without being triggered, and without being damaged thereby.
  • thyristors may be damaged in the direction of closing, whereby they must be essentially designed that their closing voltage is higher than the transmission voltage of the Triacs.
  • FIG. 12 of the drawing Another embodiment of the temperature control is disclosed in FIG. 12 of the drawing, and essentially corresponds to the circuit diagram illustrated in FIG. Ill.
  • a contact thermometer 7 of the safety switching circuit, or a transistor 40 of the current control circuit may be utilized as the trigger for a pn-transmission.
  • a transistor-trigger it is particularly useful to utilize a transistor having a single transmission, a so-called Unijunction-Transistor (UJT).
  • UJT Unijunction-Transistor
  • the safety switching circuit incorporates a thyristor 36, a resistance 24-, and a thermal safety device incorporating the wire 25.
  • the remaining elements of the safety circuit may correspond with those in FIG. ll 1, or reversely.
  • the transistor 40 replaces trigger diode 26 and receives a control voltage from point A. At point A the voltage is led at one side toward thermistor 7, and at the other side toward contact thermometer 7.
  • the advantage of this circuit lies in that between points C and D the voltage reaches only approximately 3 to 4 volts, thereby permitting the utilization of currently available thermistors.
  • resistors having positive temperature-coefficients FTC-resistors.
  • FTC-resistors resistors having positive temperature-coefficients
  • the various circuits may be utilized for all voltage ranges. However, individual elements, and particularly resistances 24, 28, 31 and thyristors 23, 27 and 36 must be selected in accordance with the predetermined operative voltage. Furthermore, the alternating current thyristor 19, the heat resistance of heating element 2 and the electrical coils for the drive of mixing device 8 must also be selected in conformance with the required operative parameters.
  • Immersion heater including an automatic temperature control; comprising a heating element adapted to be immersed in a fluid for heating thereof, and a fluid mixing device operatively connected to said heatingelement for imparting agitating motion to said heated fluid, said fluid mixing device comprising a circular plate member, said plate member being axially reciprocable in directions extending normal to the surface thereof.
  • Immersion heater as claimed in claim 1, comprising a source of electrical control current connected to said heating element, including temperature sensing means, the electrical control current flow to said element being responsive to said temperature sensing means, safetyswitch circuit means positioned in the electrical control current circuit of said heating element, said electrical control current circuit and said safety switch comprising a contactless switch including I ture extending in the direction of movement of said plate member.
  • Immersion heater as claimed in claim 4, wherein said nozzle aperture comprises a tapered bore diameter extending along the length of said aperture.
  • said fluid mixing device comprising an electrical induction coil
  • said induction coil including a movable iron core fastened to said plate member for imparting axial movement thereto in response to energization of said coil.
  • Immersion heater as claimed in claim 7, comprising a stationary iron core in proximate relationship with said movable iron core, said induction coil being rigidly fastened to said stationary iron core.
  • Immersion heater as claimed in claim 8, said stationary iron ore having a recessed portion, said movable iron core having portions thereof extending into said recessed core portion.
  • Immersion heater as claimed in claim 1 comprising means for imparting reverse axial movement to said plate member.
  • Immersion heater as claimed in claim 11 said membrane being formed of corrugated sheet metal.
  • Immersion heater as claimed in claim 9, comprising a membrane means connected to said plate member for imparting reverse axial movement thereto, receptacle means encompassing said induction coil and said movable and stationary iron cores, said membrane means comprising a cover fastened to said receptacle so as to form jointly therewith a sealed housing for said induction coil and said iron cores.
  • Immersion heater as claimed in claim 7, comprising a plurality of said plate members adapted to be axially moved in response to energization of said induction coil.
  • Immersion heater as claimed in claim 1, said heating element having an upper and a lower surface, said fluid mixing device being rigidly fastened to the upper surface of said heating element.
  • Immersion heater as claimed in claim 3 comprising a first one of said regulating resistance in the electrical control current circuit, and a second regulating resistance in said safety switch circuit means, said first and second resistances forming a tandem-potentiometer.
  • said thyristor trigger including a glow tube forming a control lamp.
  • said thyristor trigger comprising a contact thermometer.
  • said thyristor trigger comprising a transistor.
  • Immersion heater as claimed in claim 19 said transistor comprising a transistor havinga single pntransition.
  • Immersion heater as claimed in claim 2 comprising a condensator-type RC-element, and a resistance in said safety switch circuit means providing for instantaneous actuation of the trigger and thyristor.
  • Immersion heater as claimed in claim 2 comprising at least one resistance for reducing the circuit current intensity required for the safety switch circuit means actuating current.
  • Immersion heater as claimed in claim 2 comprising current stabilizers, current reference tubes, Zener reference diodes, and Zener diodes for reducing the operating circuit current intensities, and providing for elimination of current fluctuations.
  • Immersion heater as claimed in claim 2, comprising a low-temperature melting member, said member receiving electrical current flowing across a resistance of said safety switch, said member adapted to be melted rent supply circuit of said heating element, said safety upon heating during current flow so as to interrupt flow of current to said heating element.
  • Immersion heater as claimed in claim 2 compris- Sald heatmg element ing instantaneously-operative safety means in the curmeans shutting-off said heater by short-circuiting of

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Temperature (AREA)
  • General Induction Heating (AREA)
  • Control Of Resistance Heating (AREA)
US00248000A 1971-04-28 1972-04-27 Immersion heater Expired - Lifetime US3766358A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT368071A AT312760B (de) 1971-04-28 1971-04-28 Tauchsieder

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US3766358A true US3766358A (en) 1973-10-16

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US00248000A Expired - Lifetime US3766358A (en) 1971-04-28 1972-04-27 Immersion heater

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US (1) US3766358A (de)
AT (1) AT312760B (de)
CH (1) CH542566A (de)
DD (1) DD95895A5 (de)
DE (1) DE2218808A1 (de)
ES (1) ES402184A1 (de)
FR (1) FR2134691B1 (de)
GB (1) GB1333345A (de)
IT (1) IT954905B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4103319A (en) * 1977-06-27 1978-07-25 Radiant Technology Corporation Hazard prevention circuit for immersion heaters
US4278873A (en) * 1980-02-04 1981-07-14 General Electric Company Temperature-responsive control means
US20050233025A1 (en) * 2004-04-19 2005-10-20 Scimed Life Systems, Inc. Catheter balloon mold form and molding process
US9234678B1 (en) * 2011-09-27 2016-01-12 Rheem Manufacturing Company Stackable water heater apparatus
USD1020120S1 (en) * 2023-08-02 2024-03-26 Hong Kong Young Brother International Group Limited Bird bath heater

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT412333B (de) * 2003-01-15 2005-01-25 Pewag Austria Gmbh Gleitschutzkette
DE102005038994B4 (de) * 2005-08-16 2009-11-12 Drescher, Rüdiger Temperiervorrichtung
GB2433847A (en) * 2005-12-29 2007-07-04 Tyco Electronics Heat operated electrical isolator
DE102007006334B4 (de) * 2007-02-08 2009-10-01 Mars Inc. Vorrichtung und Verfahren zum induktiven Erwärmen eines Materials

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1692270A (en) * 1927-01-10 1928-11-20 Jensen Aage Apparatus for treating liquids
US2418254A (en) * 1944-10-05 1947-04-01 Russell R Fleharty Testing device
US3147364A (en) * 1962-08-30 1964-09-01 Socony Mobil Oil Co Inc Constant-temperature bath
US3381112A (en) * 1965-07-15 1968-04-30 Paul Kolb A G Electric boiler for central heating

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1692270A (en) * 1927-01-10 1928-11-20 Jensen Aage Apparatus for treating liquids
US2418254A (en) * 1944-10-05 1947-04-01 Russell R Fleharty Testing device
US3147364A (en) * 1962-08-30 1964-09-01 Socony Mobil Oil Co Inc Constant-temperature bath
US3381112A (en) * 1965-07-15 1968-04-30 Paul Kolb A G Electric boiler for central heating

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4103319A (en) * 1977-06-27 1978-07-25 Radiant Technology Corporation Hazard prevention circuit for immersion heaters
US4278873A (en) * 1980-02-04 1981-07-14 General Electric Company Temperature-responsive control means
US20050233025A1 (en) * 2004-04-19 2005-10-20 Scimed Life Systems, Inc. Catheter balloon mold form and molding process
US7892478B2 (en) * 2004-04-19 2011-02-22 Boston Scientific Scimed, Inc. Catheter balloon mold form and molding process
US20110165284A1 (en) * 2004-04-19 2011-07-07 Boston Scientific Scimed, Inc. Catheter balloon mold form and molding process
US8062024B2 (en) 2004-04-19 2011-11-22 Boston Scientific Scimed, Inc. Catheter balloon mold form and molding process
US9234678B1 (en) * 2011-09-27 2016-01-12 Rheem Manufacturing Company Stackable water heater apparatus
US9835359B1 (en) 2011-09-27 2017-12-05 Rheem Manufacturing Company Stackable water heater apparatus
USD1020120S1 (en) * 2023-08-02 2024-03-26 Hong Kong Young Brother International Group Limited Bird bath heater

Also Published As

Publication number Publication date
AT312760B (de) 1974-01-25
FR2134691A1 (de) 1972-12-08
DD95895A5 (de) 1973-02-20
IT954905B (it) 1973-09-15
CH542566A (de) 1973-09-30
DE2218808A1 (de) 1972-11-23
FR2134691B1 (de) 1975-07-18
GB1333345A (en) 1973-10-10
ES402184A1 (es) 1975-03-01

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