EP4303903A1 - Thermostat à tige avec sécurité - Google Patents

Thermostat à tige avec sécurité Download PDF

Info

Publication number
EP4303903A1
EP4303903A1 EP23181396.5A EP23181396A EP4303903A1 EP 4303903 A1 EP4303903 A1 EP 4303903A1 EP 23181396 A EP23181396 A EP 23181396A EP 4303903 A1 EP4303903 A1 EP 4303903A1
Authority
EP
European Patent Office
Prior art keywords
safety
rod
thermostat
lever
engagement element
Prior art date
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.)
Pending
Application number
EP23181396.5A
Other languages
German (de)
English (en)
Inventor
Gianluigi BELLONI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Termoregolatori Campini Corel SpA
Original Assignee
Termoregolatori Campini Corel SpA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Termoregolatori Campini Corel SpA filed Critical Termoregolatori Campini Corel SpA
Publication of EP4303903A1 publication Critical patent/EP4303903A1/fr
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/002—Thermally-actuated switches combined with protective means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/64—Contacts
    • H01H37/70—Resetting means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/12—Means for adjustment of "on" or "off" operating temperature
    • H01H37/22—Means for adjustment of "on" or "off" operating temperature by adjustment of a member transmitting motion from the thermal element to contacts or latch

Definitions

  • the present invention relates to a thermostat, in particular a rod thermostat with safety.
  • the present invention finds a preferred, but non-limiting application in the field of rod thermostats, provided for use in electric water heaters and preferably equipped with a bipolar safety.
  • Rigid rod thermostats are electromechanical devices for keeping a temperature within a specific narrow range, performing opening of an electric power supply circuit of heating means of the apparatus whereon they are mounted upon reaching a specific predetermined temperature and closing of the circuit, when the temperature has lowered by a specific differential.
  • Known rigid rod thermostats comprise a safety system, typically a bipolar safety system, which intervenes and performs opening of the electric power supply circuit of the heating means of the apparatus whereon they are mounted upon reaching a second predetermined safety temperature, and closing of the circuit by manual reset.
  • the safety system is used to avoid reaching excessive heating temperatures, which are potentially dangerous to the user.
  • bipolar safety for rod thermostats involve a bimetallic disc, or a bimetallic rod, or a shape-memory spring.
  • WO2005119720A1 relates to a thermostat comprising an electromechanical system for temperature control arranged in a pedestal enclosure closed by an casing, wherein the temperature control system is composed of a probe provided with a high-expansion metal tube in which a low-expansion metal rod is arranged, a safety device for opening safety breakers when the temperature exceeds a minimum thermal threshold thereof and a holding device for converting the low-expansion movement of the safety device into a sudden movement for opening the contacts of the elastic blades of each safety switch; the retention device temporarily acts onto a sliding unit which comes into contact with each safety breaker and is connected to the safety device.
  • Document EP0749141A1 relates to a thermostat which comprises a plastic base and a metal probe; two contacts attached to the base connect the thermostat in series with the power supply an immersion electrical heater; the conductor blades connect each of the two contacts to a safety breaker; the probe comprises a metal tube housing a rod cooperating with a regulation device; the base is provided with a recess which houses a spring of a shape-memory alloy.
  • Document GB2172749A relates to a thermostat having a safety device for cutting off the supply of heat if the temperature increases in an excessive manner, wherein the tube is attached in a bore of a boss of a thermally conductive plate by forcedly fitting a sleeve at the end of the tube; a reversible concave washer is arranged in the plate, which cooperates with a slide block which is capable of cutting off the power supply current when too high a temperature is transmitted to said washer.
  • Document WO2002097841A1 relates to an immersion thermostat for water boilers, having an elastic element, pre-compressed by a pressing member and equipped with such an expansion capacity and elastic force as to force the opening of a pair of safety electric contacts, in case the sensors and actuators providing for the good thermostat operation suffer a failure.
  • bimetallic-disc safety systems have the disadvantage of operating on air and far from the temperature sensing point. Moreover, bimetallic-disc safety systems are subjected to the effect of external temperature variations, the bimetallic disc being outside the water heater.
  • safety systems with a bimetallic rod positioned inside the resistor bulb in contact with the water of the water heater in view of the very limited increase in temperature by about one degree every 4 minutes, can be subjected to misalignments or pre-bending which damage or cause the contacts which are present on the spring assembly to seize up.
  • safety systems with a shape-memory spring involve slow expansions which can cause the contacts which are present on the spring assembly to seize up.
  • An object of the present invention is to solve drawbacks of the prior art.
  • a particular object of the present invention is to provide a safety system with a bimetallic rod which is more reliable.
  • a particular object of the present invention is to provide a safety system with a bimetallic rod which is more effective.
  • a further particular object of the present invention is to provide a safety system which is less exposed to damages or disservices.
  • a further particular object of the present invention is to provide a safety system which prevents the contacts which are present on the spring assembly from seizing up.
  • a further particular object of the present invention is to enhance the safety, in particular a bipolar safety, of a rod thermostat.
  • An idea underlying the present invention is to provide a thermostat with a lever safety, being snap-openable through a sliding element; the use of a linkage safety system allows the sliding element with manual reset button to be used.
  • the thermostat comprises: a thermostat body; a tubular element projecting from the thermostat body; a rod with differential thermal expansion, axially inserted in the tubular element and protruding at a proximal end inside the thermostat body.
  • the thermostat comprises a temperature regulation system associated with the rod and configured to reversibly open at least one electric contact in the thermostat body upon reaching an operating temperature.
  • the thermostat comprises a safety lever arranged transversally to the rod and configured for a displacement under a thermal expansion action transmitted through the rod.
  • the safety lever comprises a first engagement element.
  • the safety lever is configured to open at least one electric contact in the thermostat body upon reaching a safety temperature.
  • the thermostat comprises a reset element arranged transversally to the rod and sliding under an action of a first bias member.
  • the reset element comprises a second engagement element configured to cooperate with the first engagement element of the safety lever, defining a trip of the reset element.
  • the reset element trips between a first operating position and a second safety position. In the second safety position the reset element allows a movement of the safety lever to open the at least one electric contact upon reaching the safety temperature.
  • the safety lever is configured to open two respective electric contacts defining a bipolar safety.
  • the rigid rod thermostat is formed by a plastic body to which a brass tube containing an INVAR rod is attached.
  • the thermostat integrates two functions: a temperature regulation function through a lever which acts onto an electric assembly, and a safety function through a linkage system intervening at a given safety temperature by preferably disconnecting the contacts of both phases at the same time.
  • Figure 1 illustrates a perspective view of a preferred embodiment of the thermostat 100 according to the present invention.
  • the rod thermostat 100 comprises a main containment or housing body 1, having a generally circular shape, closed by a plastic lid 21, particularly clipengaged onto the lid.
  • the temperature regulation devices and the safety devices are housed in the thermostat body 1.
  • a brass tube 24 containing an INVAR rod is provided.
  • the housing of the thermostat body 1, the lid 21 and the internal levers are made of a plastic material which is resistant to temperatures exceeding 100°C.
  • FIG. 2 illustrates a side view of the thermostat 100, highlighting two section lines I-I and II-II.
  • the thermostat 100 comprises a thermostat body 1 and a tubular element 24 projecting from the thermostat body 1.
  • Figure 3 illustrates the section I-I of the thermostat 100 in an operating condition whereas Figure 4 illustrates the section I-I of the thermostat 100 in a safety condition.
  • Figure 5 illustrates the second section II-II of the thermostat 100 in an operating condition whereas Figure 6 illustrates the second section II-II of the thermostat 100 in a safety condition.
  • the thermostat 100 comprises a thermostat body 1 and a tubular element 24 projecting from the thermostat body 1.
  • the thermostat 100 further comprises a rod 2 with differential thermal expansion, which is axially inserted in the tubular element 24 which is hollow inside.
  • the rod 2 protrudes at a proximal end inside the thermostat body 1.
  • the tubular element 24 is made of a high-thermal-expansion metal material, preferably of brass, whereas the rod 2 is made of a lowthermal-expansion material, preferably of an INVAR alloy or a Ni-Fe alloy.
  • the rod 2 is distally constrained to the tubular element 24, i.e., in the farthest position of the rod 2 with respect to the thermostat body. It is thereby possible to determine a thermal expansion action transmitted through the rod, which is used for the operation, inter alia, of the safety system, as it will be described.
  • the thermostat 100 further comprises a safety lever 16 arranged transversally to the rod 2 and configured for a displacement under a thermal expansion action transmitted through the rod.
  • a safety lever 16 arranged transversally to the rod 2 and configured for a displacement under a thermal expansion action transmitted through the rod.
  • the differential thermal expansion between the rod 2 and the tubular element 24 involves a displacement of the proximal end of the rod 2, due to different thermal expansions of the elements.
  • the length of the tubular element 24 increases with respect to the length of the rod 2, involving a partial extraction and a lowering (with respect to the direction shown in figure) of the proximal end of the rod 2, which is connected to the safety lever as it will be further described.
  • the safety lever 16 comprises a first engagement element 16a, whose function will be described below.
  • the safety lever 26 is configured to open at least one electric contact 5, 7 in the thermostat body 1 upon reaching a safety temperature.
  • the safety lever 16 comprises a safety regulation element 18 constrained to the rod 2 and configured to regulate a position of the safety lever 16 with respect to the safety temperature.
  • the regulation of the safety temperature by means of the safety regulation element 18 is performed by calibrating the element during manufacturing thereof.
  • the safety lever 16 is preferably configured to act onto at least one elongated flexible element 6 to open the at least one electric contact 5, 6.
  • the thermostat 100 further comprises a reset element 3 arranged transversally to the rod 2 and sliding under an action of a first bias member 4, in particular a coil spring 4 but it could be another thrust element or a different spring.
  • the first bias member 4 is configured for a thrust of the reset element 3 in a radially external direction with respect to the thermostat body 1, said first bias member preferably comprising a coil spring.
  • the safety lever 16 also comprises a second bias member 17, in particular a coil spring 17 or other system, configured to partially counteract the thermal expansion action of the rod.
  • a second bias member 17 in particular a coil spring 17 or other system, configured to partially counteract the thermal expansion action of the rod.
  • the reset element 3 comprises a second engagement element 3a configured to cooperate with the first engagement element 16a of the safety lever 16.
  • the first engagement element 16a and the second engagement element 3a define a trip of the reset element 3 between a first operating position and a second safety position, in said second safety position the reset element 3 allowing a movement of the safety lever 16 to open the at least one electric contact 5,7 upon reaching the safety temperature, as it is exemplified in particular in Figures 4 and 6 .
  • first engagement element 16a and the second engagement element 3a comprise respective front surfaces, configured to abut with each other in the first operating position, see the enlargement in Figure 5 , and further configured to overtake each other in the second safety position, see the enlargement in Figure 6 , so as to move the first engagement element 16a beyond the second engagement element 3a by tripping.
  • the respective front surfaces of the first engagement element 16a and second engagement element 3a are slightly tilted, to promote the movement of the safety lever 16 under the modest thermal expansion force exerted by the rod 2.
  • the reset element 3 comprises a hook element 3b having the second engagement element 3a
  • the safety lever 16 comprises a groove 16b for slidingly housing the hook element 3b at the first engagement element 16a.
  • the reset element 3 further comprises a tab 3c configured to laterally protrude beyond the thermostat body 1 by sliding the reset element 3 in the second safety position.
  • the tab 3c is adapted to bring the reset element 3 back in the first operating position, i.e., to go from the condition of Figure 6 back to the condition of Figure 5 , by mechanically counteracting the action of the first bias member 4 for example by means of a manual pressure of a user onto the tab 3c.
  • the safety lever 16 defines a fulcrum 16c, and the rod 16 itself is interposed between the fulcrum 16c and the first engagement element 16a, thus defining a class-III lever with respect to the thermal expansion action transmitted through the rod 2, so as to amplify a movement of the first engagement element 16a with respect to the second engagement element 3a.
  • the thermostat 100 further comprises a temperature regulation system associated with the rod 2 and configured to reversibly open at least one electric contact 14, 15 in the thermostat body 1 upon reaching an operating temperature.
  • the temperature regulation system of the thermostat 100 comprises a regulation lever 19 arranged transversally to the rod 2 and above the safety lever 16 (with respect to the figure direction).
  • the regulation lever 19 is configured for a displacement under a thermal expansion action of the rod 2.
  • the temperature regulation system further comprises a temperature regulation element 20 constrained to the rod 2 and configured to regulate a position of the regulation lever 19 with respect to the operating temperature; in other words, the intervention temperature of the thermostat 100 is settable, also by a user, in particular by acting onto the regulation element 19 via an interface element 22.
  • FIG. 7 illustrates a perspective view of an alternative embodiment of the thermostat body 1' according to the present invention
  • Figure 8 illustrates a section of the thermostat body 1'.
  • the safety lever 16' directly integrates the second bias member, configured to partially counteract the thermal expansion action of the rod 2.
  • the second bias member provides, instead of a coil spring, a flexible cantilever 16c' at the fulcrum of the safety lever 16', made in particular as a single piece with the thermostat body 1.
  • Figure 9 illustrates an exploded view of the first preferred embodiment of the thermostat according to the present invention, already described with reference to Figures 1 to 6 .
  • thermostat 100 The main components of the thermostat 100 are identified in this exploded view, some of them have already been described above and shown with the same reference number, whereas others are ancillary components identified below for the first time in the description.
  • the present invention allows a thermostat 100 to be manufactured, having a safety system preferably composed of a manually resettable valve 3, two springs and an upper safety lever 16 snap-fixed on the thermostat body 1.
  • a calibration element 18 of the safety intervention temperature is positioned by using an INVAR rod 2.
  • the INVAR rod 2 With the increase in temperature, the INVAR rod 2 remains fixed and the brass tubular element 24 expands creating a force which lowers the upper lever 16 and trips the lower valve 3 when there is no longer any contact between the tooth 3a which is present on the valve and the portion 16a of the upper lever 16.
  • the trip of the safety valve 3 is instant upon reaching the safety temperature, and trips the two springs 7 opening the electric contacts.
  • the safety is manually resettable after each single intervention, by acting onto the element 3c.
  • the specific configuration and mutual shaping of the safety lever and reset element might be modified based on the thermostat model, in particular based on considerations about the overall layout, overall dimensions and space which is available inside the thermostat body.

Landscapes

  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Thermally Actuated Switches (AREA)
EP23181396.5A 2022-07-04 2023-06-26 Thermostat à tige avec sécurité Pending EP4303903A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT202200014128 2022-07-04

Publications (1)

Publication Number Publication Date
EP4303903A1 true EP4303903A1 (fr) 2024-01-10

Family

ID=83270846

Family Applications (1)

Application Number Title Priority Date Filing Date
EP23181396.5A Pending EP4303903A1 (fr) 2022-07-04 2023-06-26 Thermostat à tige avec sécurité

Country Status (1)

Country Link
EP (1) EP4303903A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2172749A (en) 1985-03-18 1986-09-24 Cotherm Sa Thermostat
FR2707424A3 (fr) * 1993-04-28 1995-01-13 Lorenzi Vasco Spa Thermostat à tige pour chauffe-eau à double action de sûreté et basse inertie thermique d'intervention.
EP0749141A1 (fr) 1995-06-12 1996-12-18 Cotherm Thermostat à sonde comportant dans le socle un ressort en alliage à mémoire de forme
WO2002097841A1 (fr) 2001-05-28 2002-12-05 Thermowatt S.P.A. Thermo-protecteur non redeclenchable dote d'une securite active
WO2005119720A1 (fr) 2004-05-26 2005-12-15 Cotherm Thermostat de regulation a dispositif de retenue
GB2474238A (en) * 2009-10-06 2011-04-13 Heatrod Elements Ltd Thermostatic and thermal cut-out switch

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2172749A (en) 1985-03-18 1986-09-24 Cotherm Sa Thermostat
FR2707424A3 (fr) * 1993-04-28 1995-01-13 Lorenzi Vasco Spa Thermostat à tige pour chauffe-eau à double action de sûreté et basse inertie thermique d'intervention.
EP0749141A1 (fr) 1995-06-12 1996-12-18 Cotherm Thermostat à sonde comportant dans le socle un ressort en alliage à mémoire de forme
WO2002097841A1 (fr) 2001-05-28 2002-12-05 Thermowatt S.P.A. Thermo-protecteur non redeclenchable dote d'une securite active
WO2005119720A1 (fr) 2004-05-26 2005-12-15 Cotherm Thermostat de regulation a dispositif de retenue
GB2474238A (en) * 2009-10-06 2011-04-13 Heatrod Elements Ltd Thermostatic and thermal cut-out switch

Similar Documents

Publication Publication Date Title
EP1267454B1 (fr) Combinaison de commande/connecteur pour applications électriques sans fil
US6153859A (en) Liquid heating vessels
EP0564150A1 (fr) Dispositif de protection contre surintensité
US5847638A (en) Thermal circuit protector and switch
US20050231318A1 (en) Trip-free limit switch and reset mechanism
CA1206505A (fr) Protection d'elements sous eau
JP2001006513A (ja) 熱動遮断器及び開閉器
GB2181598A (en) Thermally-sensitive controls
US2897319A (en) Electric switch
JPS5935613B2 (ja) 過熱保護スイツチ付電気式料理板
EP4303903A1 (fr) Thermostat à tige avec sécurité
US3959691A (en) Motor protector
EP1312289A1 (fr) Chauffe-eau utilisant un systeme de commande de la temperature
US5685481A (en) Trip-free high limit control
US4360725A (en) Overtemperature protector for an electrically heated appliance
US4313047A (en) Combined thermostatic control and thermal fuse overtemperature protector for electrical heating appliances
GB2251986A (en) Switched electrical contacts for cordless appliances
GB2185857A (en) Controls for vessels for heating liquids
EP1535491A2 (fr) Ameliorations apportees a un thermostat de chauffe-eau
US5323550A (en) Sole plate temperature control including differential expansion
CN211743049U (zh) 用于无缆线电气器具的热控制件及无缆线电气器具
GB2206734A (en) Thermally responsive electrical device
EP2494572A2 (fr) Améliorations à et associés à des thermostats
GB2329523A (en) Thermally sensitive controls
WO1993016569A1 (fr) Corps de chauffe par immersion

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN PUBLISHED

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC ME MK MT NL NO PL PT RO RS SE SI SK SM TR