US3525967A - Safety switch arrangement for electrical resistance heaters - Google Patents

Safety switch arrangement for electrical resistance heaters Download PDF

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Publication number
US3525967A
US3525967A US747659A US3525967DA US3525967A US 3525967 A US3525967 A US 3525967A US 747659 A US747659 A US 747659A US 3525967D A US3525967D A US 3525967DA US 3525967 A US3525967 A US 3525967A
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United States
Prior art keywords
tube
electrical resistance
safety switch
switch arrangement
resistance heaters
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US747659A
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English (en)
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Siegfried Stauber
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Individual
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Individual
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/20—Arrangement or mounting of control or safety devices
    • F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
    • F24H9/2014—Arrangement or mounting of control or safety devices for water heaters using electrical energy supply
    • F24H9/2028—Continuous-flow heaters
    • A—HUMAN NECESSITIES
    • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
    • A47J31/00—Apparatus for making beverages
    • A47J31/44—Parts or details or accessories of beverage-making apparatus
    • A47J31/54—Water boiling vessels in beverage making machines
    • A47J31/542—Continuous-flow heaters
    • A47J31/545—Control or safety devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/10—Control of fluid heaters characterised by the purpose of the control
    • F24H15/128—Preventing overheating
    • F24H15/132—Preventing the operation of water heaters with low water levels, e.g. dry-firing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/32—Thermally-sensitive members
    • H01H37/46—Thermally-sensitive members actuated due to expansion or contraction of a solid
    • H01H37/48—Thermally-sensitive members actuated due to expansion or contraction of a solid with extensible rigid rods or tubes

Definitions

  • FIG. 7 shows Aug. 25, 1970 s. STAUBER 6 SAFETY SWITCH ARRANGEMENT FOR ELECTRICAL RESISTANCE HEATERS Filed July 25, 1968 FIG 2 FIG. 7
  • a safety switch arrangement for electrical resistance heaters comprising tube means, the length of which varies as a function of temperature.
  • a heat generating element is arranged at one side of the tube means and a heat absorbing medium is disposed at the other side thereof.
  • means are provided for fixedly retaining one end of the tube means.
  • a member, such as a switch or transducer or the like, actuated in response to changes in the absolute length of said tube means is operably associated with the other free end of such tube means.
  • the changes in the absolute length of the tube means constitute a measure for the generation of heat and the transmission of heat.
  • Transmission means cooperate with the tube means and the actuated member, said transmission means and said actuated member being situated at the same side of said heat generating element.
  • the present invention relates to an improved safety switch arrangement for electrical resistance heaters of the type incorporating an elongate carrier or support for the heating wires or the heating layer.
  • a further, more specific object of the present invention relates to an improved safety switch arrangement for resistance heaters which is quick to respond, thereby ensuring for effective protection of the heater unit.
  • Still a further important object of the present invention relates to an improved safety switch arrangement for electrical heaters which is relatively simple in construction, economical to manufacture, extremely reliable in operation, and provides positive protection for the associated heater structure.
  • the inventive safety switch arrangement for electrical resistance heaters is manifested by the features that, there is provided a support which is rigidly fixed at one end and the other end of which is operably associated with an electrical switch in such a manner that changes in the length of the support, owing to heating thereof, cause actuation of a switch.
  • FIG. 1 depicts, partly in cross-section, an exemplary emcbodiment of inventive safety switch arrangement
  • FIG. 2 is a fragmentary schematic view of a beam or blade spring which can be used in the arrangement of FIG. 1 instead of the rod member thereof.
  • this electrical resistance heating element 2 possesses the form of a uniform electrically conductive jacket or covering 2a.
  • a covering 2a it also would be possible to wind upon the tube 1 a conventional helical or screw-like winding of a resistance wire.
  • a suitable liquid or fluid medium which is to be heated is conducted through the inside of the hollow glass tube 1, so that this tube 1 serves as a through-pass heater.
  • a clamp clip or ring 3 which is fixedly secured to the tube 1 and serves for the attachment of a rod member 4.
  • this rod member 4 extends in parallelism with the tube .1 and is spaced somewhat therefrom.
  • the actual clamping action is achieved by means of a suitable screw 5 or similar fastening expedient.
  • the lower end 1b of the tube 1 is rigidly retained in a housing 6 or other type of suitable member.
  • the fluid medium to be heated is delivered from the housing 6, through the agency of a suitable opening 6a, into the tube 1, leaving the latter at the upper region thereof.
  • a further clamping clip or ring 7 is located at the region of the housing 6.
  • a resilient arm member 8 extends from this clamp ring 7 transverse to the longitudinal axis of the tube 1.
  • the outer free end 8a of the resilient arm member 8 carries a mercury tilt switch 9.
  • the lower end 4a of the rod member 4 is provided with threading 10 upon which is threaded a threaded nut member 11 hearing against the underside of the resilient arm member 8.
  • a wire loop 13 depends from a contact 12 provided at the mercury tilt switch 9. This Wire loop 13 is electrically coupled with the heater unit.
  • the electrical current circuit for the heater unit is closed, and in the reverse manner, when the mercury bead 14, during inclined position of the arm member 8, is not in contact with the contact 12, then this current circuit is interrupted.
  • suitable electrical insulating material or means is provided in order to conduct the flow of current in the desired direction and to protect against contact with current-conducting components.
  • the heating unit 2 is switched in and thermal energy or heat transmitted to the tube 1 and, therefore to its contents, then the tube 1 tends to expand in its lengthwise direction, so that the clamp member 3 moves somewhat toward the top, therefore entrains the movement transmitting-rod member 4.
  • the move ment of the rod member 4 is transmitted via the nut memher 11 to the horizontal transmission arm member 8 and, therefore, to the mercury tilt switch 9.
  • the resilient arm member 8 tends to bend through somewhat owing to the displacement of the rod member 4.
  • the mercury drop or bead 14 comes out of contact with the contact 12, so that the supply of current for heating purposes is interrupted.
  • the tube 1 When the tube 1 has cooled, then there occurs a movement of the arm member 8 in the opposite direction, whereupon the mercury switch 9 is again switched in.
  • the threaded nut member 11 By appropriately rotating the threaded nut member 11 it is possible to adjust the response temperature of the mercury switch 9.
  • the length of the tube member 1 should at least amount to 30 times its maximum Width.
  • the spaced arrangement of the rod member 4 with respect to the tube 1 brings about a so-called displacement transmission or displacement advantage in that the path of displacement of the single arm-lever member 8 at its free end 8a is greater than at the location of its attachment, which could also be a pivotal attachment.
  • a tiltable mercury switch instead of using a tiltable mercury switch, it would be possible to use a difierent type of switch, for instance a Inicroswitch, or some other suitable type of transducer. Furthermore, it would be possible to arrange the switch at the upper end of the tube and, at this location for instance, to actuate such through the agency of a double-arm lever member with markedly different lengths of the lever arms.
  • a difierent type of switch for instance a Inicroswitch, or some other suitable type of transducer.
  • the switch at the upper end of the tube and, at this location for instance, to actuate such through the agency of a double-arm lever member with markedly different lengths of the lever arms.
  • the arm member 8 it is also possible to construct the arm member 8 longer and to provide at the free end 8a of this arm member 8 a manual actuation lever or knob 20, as shown in phantom lines in FIG. 1, thereby enabling the performance of a switching-in operation manually.
  • the switching-out operation then occurs automatically as a function of the heating of the tube member 1, since the mercury tilt switch 9 is arranged in the current circuit of the heater unit 2 or influences such through the agency of intermediate elements.
  • a further embodiment of the invention resides in the fact that instead of using a tube as the support or carrier for the heating windings, there is employed a solid rod, whereby this apparatus then may be used as a room heating device, as an immersion rod or the like.
  • the rod member 4 it would be possible to arrange the rod member 4 such that it does not extend in juxtaposition parallel to the rod or tube carrying the heating winding, rather that it is either arranged internally of the tube member 1 or, however, is constructed as a larger size tube which extends about the rod or tube and, therefore, about the heating device, whereby then the lower end is used in analogous manner for actuating a switch or the like.
  • a further variant of the throughpass heater unit resides in manufacturing the tube 1 itself from a material which during the passage of current heats up to a desired degree, such as would be achieved by forming the tube 1 itself of a suitable current conducting electrical resistance material.
  • the rod member 4 such that it is not flexurally stiff or rigid, rather is constructed in the form of a flat spring 30 (FIG. 2) which is rigidly connected or supported at its lower end and which bends through when it is in cold condition.
  • a switching pin or a microswitch or the like would then bear approximately at the center against this bent or flexed flat spring 30, which would then actuate such switch as soon as, during a predetermined or impermissible heating, the upper attachment location for this spring, due to expansion of the tube 1, is displaced toward the top, and consequently the bending through of the blade or leaf spring becomes smaller.
  • the thus resulting change of the bending through is greater, so that in this manner a transmission ratio is obtained which provides a suflicient switching path for the switch.
  • the spring 30 or the rod member 4' generally could, instead of depending downwardly from the clamping ring or member 3, also depend upwardly, whereby then the increase of the bending through of the spring can be utilized for actuating the switch.
  • the tube member accordingly changes its lengthwise expansion, and the switch responds as soon as it has reached the critical lengthwise elongation, completely independent of the reason why such body member has reached such critical lengthwise expansion.
  • a safety switch arrangement for electrical resistance heaters comprising: heater tube means defining a through flow passage for conducting a heat-absorbing medium to be heated therein, the length of said tube means being temperature dependent wherein changes in the absolute length of said tube means constitute a measure of the generation and transmission of heat; heat generating element means disposed about the outside of said tube means for heating said tube means and the heatabsorbing medium conducted therein; means for fixedly retaining one end of said tube means; a rod member extending substantially parallel to and at a distance away from the outside of said tube means; means for fixedly securing one end of said rod member to the free end of said tube means; a lever arm means attached to said tube means and disposed substantially transverse to the longitudinal axis thereof; means coupling said rod member to said lever arm means whereby changes in length of said tube are transmitted by said rod member to said lever arm means; said lever arm means being actuated by said rod member as a function of the change of length of said tube means; and switch means operably associated with said lever arm means and connected to said heat generating element
  • a safety switch arrangement for electrical resistance heaters as defined in claim 4 wherein said manually operable means corri'prises a manually actuated knob 6.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Control Of Resistance Heating (AREA)
  • Resistance Heating (AREA)
  • Electric Stoves And Ranges (AREA)
US747659A 1967-07-28 1968-07-25 Safety switch arrangement for electrical resistance heaters Expired - Lifetime US3525967A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH1073267A CH476443A (de) 1967-07-28 1967-07-28 Sicherheitsschalteinrichtung für elektrische Widerstandsheizungen
AU50949/69A AU5094969A (en) 1967-07-28 1969-02-24 Safety switch arrangement for electrical resistance heaters

Publications (1)

Publication Number Publication Date
US3525967A true US3525967A (en) 1970-08-25

Family

ID=25629129

Family Applications (1)

Application Number Title Priority Date Filing Date
US747659A Expired - Lifetime US3525967A (en) 1967-07-28 1968-07-25 Safety switch arrangement for electrical resistance heaters

Country Status (8)

Country Link
US (1) US3525967A (xx)
AT (1) AT279755B (xx)
AU (1) AU5094969A (xx)
CH (1) CH476443A (xx)
DE (1) DE1765834A1 (xx)
FR (1) FR1574569A (xx)
GB (1) GB1223165A (xx)
NL (1) NL6810634A (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3989926A (en) * 1972-06-19 1976-11-02 Rank Xerox, Ltd. Device for preventing overheating of electrophotographic fixing device
US5713864A (en) * 1995-04-11 1998-02-03 Sims Level 1, Inc. Integral conductive polymer resistance heated tubing

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT8321433V0 (it) * 1983-04-05 1983-04-05 Irca Spa Limitatore di temperatura in particolare per elementi riscaldanti elettrici.
CA1284517C (en) * 1986-03-18 1991-05-28 Norbert William Ellmann Heating unit for inhalation therapy

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE562509A (xx) *
US1803852A (en) * 1929-03-11 1931-05-05 Modern Oil Well Supply Company Signal system and apparatus for boilers
US1859605A (en) * 1930-03-03 1932-05-24 Buckeye Incubator Mfg Company Electric switch
US1912921A (en) * 1930-09-08 1933-06-06 Gen Plate Co Thermostatic heater
US2187418A (en) * 1935-10-07 1940-01-16 Westinghouse Electric & Mfg Co Temperature regulator
US2793268A (en) * 1954-07-01 1957-05-21 Gen Mills Inc Thermal relay with shorting strip
US3130354A (en) * 1959-02-20 1964-04-21 Herbert S Burling Temperature control

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE562509A (xx) *
US1803852A (en) * 1929-03-11 1931-05-05 Modern Oil Well Supply Company Signal system and apparatus for boilers
US1859605A (en) * 1930-03-03 1932-05-24 Buckeye Incubator Mfg Company Electric switch
US1912921A (en) * 1930-09-08 1933-06-06 Gen Plate Co Thermostatic heater
US2187418A (en) * 1935-10-07 1940-01-16 Westinghouse Electric & Mfg Co Temperature regulator
US2793268A (en) * 1954-07-01 1957-05-21 Gen Mills Inc Thermal relay with shorting strip
US3130354A (en) * 1959-02-20 1964-04-21 Herbert S Burling Temperature control

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3989926A (en) * 1972-06-19 1976-11-02 Rank Xerox, Ltd. Device for preventing overheating of electrophotographic fixing device
US5713864A (en) * 1995-04-11 1998-02-03 Sims Level 1, Inc. Integral conductive polymer resistance heated tubing

Also Published As

Publication number Publication date
AT279755B (de) 1970-03-25
NL6810634A (xx) 1969-01-30
GB1223165A (en) 1971-02-24
DE1765834A1 (de) 1971-10-14
CH476443A (de) 1969-07-31
FR1574569A (xx) 1969-06-02
AU5094969A (en) 1970-08-27

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