EP2304517A2 - Improvements to thermostat control devices - Google Patents
Improvements to thermostat control devicesInfo
- Publication number
- EP2304517A2 EP2304517A2 EP09772790A EP09772790A EP2304517A2 EP 2304517 A2 EP2304517 A2 EP 2304517A2 EP 09772790 A EP09772790 A EP 09772790A EP 09772790 A EP09772790 A EP 09772790A EP 2304517 A2 EP2304517 A2 EP 2304517A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- drive screw
- diaphragm
- control device
- deformable member
- thermostat control
- 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.)
- Withdrawn
Links
- 230000007246 mechanism Effects 0.000 claims abstract description 9
- 230000006903 response to temperature Effects 0.000 claims abstract description 5
- 230000009471 action Effects 0.000 claims description 6
- 239000000523 sample Substances 0.000 description 9
- 239000012530 fluid Substances 0.000 description 8
- 230000009021 linear effect Effects 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000010411 cooking Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 230000004886 head movement Effects 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
-
- 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
- G05D23/275—Control of temperature characterised by the use of electric means with sensing element expanding, contracting, or fusing in response to changes of temperature
- G05D23/27535—Details of the sensing element
- G05D23/27537—Details of the sensing element using expansible fluid
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K5/00—Measuring temperature based on the expansion or contraction of a material
- G01K5/32—Measuring temperature based on the expansion or contraction of a material the material being a fluid contained in a hollow body having parts which are deformable or displaceable
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H37/00—Thermally-actuated switches
- H01H37/02—Details
-
- 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
- H01H37/36—Thermally-sensitive members actuated due to expansion or contraction of a fluid with or without vaporisation
- H01H37/40—Thermally-sensitive members actuated due to expansion or contraction of a fluid with or without vaporisation with diaphragm
Definitions
- the present invention relates to thermostatic control devices, particularly electro- mechanical thermostat devices such as temperature limiters or thermally operated switches for the control of power to a load.
- the invention more particularly relates to thermally operated switches which include a temperature-sensing probe coupled to a bellows or diaphragm, the movement of which causes the connection and disconnection of an electrical circuit, thereby regulating the operating temperature of domestic or commercial heating systems or boilers and cooking appliance loads, such as hot plates, hobs, grills, ovens and the like.
- the invention additionally relates to a diaphragm actuator for use in regulators and thermostatically controlled devices.
- thermally operated switches there are a wide variety of thermally operated switches, however, in the field of thermal control of domestic and commercial heating systems or boilers and cooking appliance controls, a familial- type of control is traditionally used.
- Such controls have a rotatable user control for setting the temperature at which switching is to occur and a temperature sensor within or adjacent the boiler, oven, grill or the like.
- the temperature sensor comprises a probe including phial of expansible fluid.
- the phial communicates with a sealed unit located within the body of the control device via a capillary system.
- the sealed unit comprises a diaphragm connected to an actuator.
- Temperature changes sensed by the phial produces a change in the volume of the filling liquid or a pressure change in the filling gas or vapour. These expansion movements are communicated via the capillary system to the diaphragm where they are converted to a linear movement within the body of the control device causing the connection and disconnection of electrical contacts.
- a reference to a temperature sensor or probe is intended to include other comparable means for effecting a temperature depended linear movement at a diaphragm or equivalent means known in the art.
- reference to a hydraulic or fluid filled temperature sensor is not intended to be in any way limiting or to exclude other systems capable of effecting temperature dependent linear movement.
- Exemplifying of prior art control devices is an electro-mechanical thermostat device such as that produced by the present Applicant (Diamond H Controls Limited, 40TH and 50TH Series thermostat controls). Hydraulic expansion of a fluid within a probe is used to produce a mechanical action within a control housing. The effect of the mechanical action (which is small) is regulated by a . cam surface to adjust the sensitivity of a spring switch mechanism to the action produced by the fluid expansion. In such devices the temperature range over which accurate detection and/or regulation is relatively small (say 50 - 350C) and response times may be slow. More particularly, the component count and the manufacturing tolerances for the hydraulic circuit within such controllers tend to make them particularly expensive.
- the thermal expansion of the hydraulic fluid is converted to mechanical movement by the separation of opposed diaphragm walls (or skins) and the movement is transmitted via an actuator element or striker arrangement to engage a switch blade.
- the force applied to the switch blade results in an electrical connection being broken and establishing an electrical separation between contact terminals.
- the striker arrangement comprises a lever system where a diaphragm head on the moving wall or skin of the diaphragm actuates one side of a lever which transfers the diaphragm head movement to a striker element, which in turn breaks the switch blade from electrical contact with a load terminal. Electrical power to a load is then broken.
- the temperature at which the movement of the diaphragm head actuates the switch blade is dependent on the position of an actuator element or striker, the position in turn being controlled via the rotatable user control knob.
- a further disadvantage is the complexity of components required to ensure connection between electrical contacts remain broken even when ambient room temperature falls substantially, for example, to -20C (minus 20 degrees
- a further object of the present invention is to provide a diaphragm actuator for use in regulators and thermostatically controlled devices, the actuator having minimal component count and is adaptable for multiple applications.
- the present invention provides a thermostat control device comprising:
- a resiliency deformable member in operable connection with a temperature sensor
- a rotatable user control spindle coaxially disposed to and adapted to move tlie drive screw with respect to the deformable member
- the deformable member operably moves the drive screw to bring a striker arrangement into and out of engagement with a moveable contact to "break" and "make” electrical connection with a fixed contact.
- the resiliency deformable member comprises a diaphragm having a profiled diaphragm head adapted to engage the drive screw.
- the drive screw has an externally threaded end which mates with an internally threaded cylindrical portion of the diaphragm head, so that the axial position of the drive screw is determined by the depth of threaded reception within said threaded portion of the diaphragm head.
- the depth of threaded reception of the drive screw within the diaphragm head is determined by the rotational adjustment of the user control spindle.
- the rotatable user control spindle receives a tabbed end of the drive screw within a receiving slot thereof, allowing rotation of the drive screw with respect to the deformable member without imparting axial movement to the user control spindle.
- the striker arrangement comprises a collar located on the drive screw and includes an actuating surface thereon which engages a switch blade carrying the moveable contact.
- the collar includes an overthrow surface adapted to engage a striker pin extending radially from the drive screw, so as to provide additional axial movement to the collar with respect to the drive screw to maintain a "break" position.
- the switch blade carrying the moveable contact comprises a leaf spring element having an over-centre snap action.
- calibration of the device is achieved by adjusting the depth of engagement between the drive screw and the diaphragm head, thereby eliminating the need for a conventional calibration screw mechanism.
- Calibration may also be achieved by adjusting the interface of the temperature sensor (specifically it's capillary system) and the diaphragm, whereby an offset value for the deflection of the diaphragm at a given temperature is selected.
- Control knobs secured on the control spindle to which a stop plate is fixed.
- a radial projection on the stop plate abuts a control surface in the housing to limit rotation of the control spindle.
- rotation of the control spindle has a range of from 0 to 330 angular degrees.
- the present invention further provides a diaphragm actuator for use in regulators and thermostatically controlled devices, the diaphragm actuator comprising:
- the resiliency deformable member comprises a diaphragm having a
- profiled diaphragm head adapted threadingly to engage the drive screw.
- the drive screw has an externally threaded end which mates with an internally threaded cylindrical portion of the diaphragm head, so that the axial position of the drive screw is determined by the depth of threaded reception within said threaded portion of the diaphragm head.
- the depth of threaded reception of the drive screw within the diaphragm head is determined by the rotational adjustment of a user control spindle.
- the rotatable user control spindle is coaxially disposed to and receives a tabbed end of the drive screw within a receiving slot thereof, allowing rotation of the drive screw with respect to the deformable member withoiit imparting axial movement to the user control spindle.
- calibration of a regulator or thermostatically controlled device is achieved by adjusting the depth of engagement between the drive screw and the diaphragm head, thereby eliminating the need for a conventional calibration screw mechanism.
- Calibration may also be achieved by adjusting the interface of the temperature sensor (specifically it's capillary system) and the diaphragm, whereby an offset value for the deflection of the diaphragm at a given temperature is selected.
- Figure 1 is a sectional side elevation of the control device
- FIG. 2 is a detailed sectional side elevation of striker overthrow feature
- Figure 3 is an exploded assembly view of the control device
- Figure 4 is a detailed sectional side elevation of a first arrangement of diaphragm actuator.
- Figure 5 is a detailed sectional side elevation of a second arrangement of diaphragm actuator. Detailed Description of Preferred Embodiments
- a thermostat control device denoted generally by reference numeral 1, comprises a main housing 2 to which there is attached a diaphragm assembly 3 defining the base of the housing.
- the diaphragm assembly 3 comprises a diaphragm 4 in sealed communication with a thermal probe 5 which include a phial of expansible fluid, such as hydraulic liquid known in the art.
- the liquid is constrained within a capillary system 6 so that thermal expansion of the hydraulic liquid is converted to movement at the diaphragm 4.
- the diaphragm 4 includes a diaphragm head 7 which has an internally threaded cylindrical receiver 8 into which a correspondingly threaded end 11 of a drive screw 12 is operably engaged.
- the axial position of the drive screw within the housing is determined by the depth of threaded reception within said threaded receiver 8.
- a striker assembly comprises a collar
- the switch blade 17 comprises a leaf spring element anchored at one end and has an over-centre snap action to facilitate automatic resetting thereof when the actuating surface of the collar is no longer in abutting contact.
- the striking collar 15 also includes an overthrow feature operating between the drive screw 12, the striker collar 15 and the switch blade 17 to assure the switch blade does not re-establish electrical contact in low ambient temperatures (typically determined to be in the region of -20C), without human intervention, to provide a guaranteed safe 'OFF" position.
- an overthrow surface 22 on the underside of the striker collar 15 abuts a pin 23 extending radially from the drive screw so as to provide additional axial movement to the collar with respect to the drive screw 12 to maintain a "break" position.
- a top portion 20 of the housing provides an electrical insulator and protection of the switch mechanism within the main housing 2 and the first and second external connecting terminal tabs (not shown) are secured in the main housing 2.
- the line terminal is further mechanical supported by the top portion 20 to prevent movement.
- a flattened axial region is formed to provide a tab 25 adapted to slidingly engage with a receiving groove 27 of a user control spindle 30.
- the user control spindle 30 is rotatable within a bearing 32 which is retained within a fixing plate 33 which in turn is secured during assembly to the top portion 20 of the housing, as illustrated in Figure 3.
- the depth to which the threaded end 11 of the drive screw 12 is engaged in the diaphragm head receiver 8 is determined by the rotational adjustment of the user control spindle 30. As the drive screw 12 moves, its axial movement is taken up within the receiving groove 27, thereby eliminating any axial movement to the user control spindle 30.
- User settings are selected on a control knob (not shown) which is secured to the free end of the user control spindle 30.
- a stop plate 35 is fixed to the control spindle to limit the range of rotation of the control knob to between 0 and 330 angular degrees. The limitation is realised by having a radial projection on the stop plate which abuts a control surface within the fixing plate 33 or the top portion 20 of the housing.
- the temperature probe 5 is located within or adjacent an oven, boiler or any other body the temperature of which is to be regulated by the thermostatic control device 1 connected to an electrical load, specifically a heater circuit.
- the thermostatic control device 1 connected to an electrical load, specifically a heater circuit.
- the hydraulic fluid in the probe 5 expands and via the capillary system 6 forces the diaphragm 4 to expand. This expansion is transmitted into linear movement at the diaphragm head 7 and from there through the drive screw 12.
- the relative position of the drive screw 12 with respect to the other components of the control device is determined by the depth to which the threaded end 11 of the drive screw 12 is retained within the correspondingly threaded receiver 8 of the diaphragm head 7.
- This critical depth is in turn determined by the rotation of the user control spindle 30 which slidingly in the axial direction engages the opposite end 25 of the drive screw 12.
- the sliding relationship between the drive screw and user control spindle means that the axial movement of the drive screw is not transferred to the user control spindle 30.
- the user control spindle can be fixed in the axial direction so that there is no increase or decrease in gap presented between the control knob (not shown) and the fixing plate 33 during rotation of the control knob to determine the temperature at which the striker arrangement, attached to
- the drive screw activates the switch blade 17, thereby breaking electrical contact between the load contacts 18,19.
- the diaphragm assembly 3 comprises a diaphragm 4, connected via a capillary system 6 to a thermal probe 5.
- the diaphragm 4 includes a diaphragm head 7 which in this construction is internally threaded as a receiver 8 for a correspondingly and externally threaded end 11 of a drive screw 12. Using this construction, the relative exposed length of the drive screw 12 is determined by the depth of threaded reception within the receiver 8 of the diaphragm head 7.
- a second arrangement of diaphragm actuator is shown in Figure 5 and shows an inverted diaphragm 4 connected to a thermal probe via a capillary system.
- the diaphragm 4 includes a threaded diaphragm head 7 for receiving a correspondingly threaded end of the drive screw 12.
- the diaphragm head 7 also includes a shoulder portion 7a supporting one end of a biasing spring which, together with a valve seat and sealable gas flow aperture, effects a thermostatically controlled gas valve.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Thermally Actuated Switches (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0811933A GB2463447A (en) | 2008-07-01 | 2008-07-01 | Thermostat control device |
PCT/GB2009/001637 WO2010001110A2 (en) | 2008-07-01 | 2009-06-30 | Improvements to thermostat control devices |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2304517A2 true EP2304517A2 (en) | 2011-04-06 |
Family
ID=39683381
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP09772790A Withdrawn EP2304517A2 (en) | 2008-07-01 | 2009-06-30 | Improvements to thermostat control devices |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2304517A2 (en) |
GB (1) | GB2463447A (en) |
WO (1) | WO2010001110A2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107369591B (en) * | 2016-11-10 | 2020-01-31 | 陈永龙 | simple liquid expansion type temperature controller |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB521599A (en) * | 1937-12-20 | 1940-05-27 | Wilcolator Co | Thermally responsive temperature regulating device |
US2762888A (en) * | 1953-09-10 | 1956-09-11 | Gen Motors Corp | Refrigerating apparatus |
US2758178A (en) * | 1955-03-09 | 1956-08-07 | Dole Valve Co | Multiple action thermostatic control devices |
US3114813A (en) * | 1960-01-15 | 1963-12-17 | Gen Electric | Temperature responsive control device |
DE1501020A1 (en) * | 1965-07-03 | 1969-10-23 | Danfoss As | Evaporator thermostat |
GB1270833A (en) * | 1969-03-11 | 1972-04-19 | Diamond H Controls Ltd | Improvements in or relating to apparatus for the control of the supply of electrical power |
GB1334709A (en) * | 1971-11-01 | 1973-10-24 | Diamond H Controls Ltd | Thermally controlled electrical switches and electrical energy regulators |
US4490708A (en) * | 1982-06-24 | 1984-12-25 | General Electric Company | Condition responsive electric switch system, electrical switching device and method of operation thereof |
US4626819A (en) * | 1985-04-17 | 1986-12-02 | Safeway Products, Inc. | Switch adjusting mechanism |
-
2008
- 2008-07-01 GB GB0811933A patent/GB2463447A/en not_active Withdrawn
-
2009
- 2009-06-30 EP EP09772790A patent/EP2304517A2/en not_active Withdrawn
- 2009-06-30 WO PCT/GB2009/001637 patent/WO2010001110A2/en active Application Filing
Non-Patent Citations (1)
Title |
---|
See references of WO2010001110A2 * |
Also Published As
Publication number | Publication date |
---|---|
GB2463447A (en) | 2010-03-17 |
WO2010001110A3 (en) | 2010-08-12 |
GB0811933D0 (en) | 2008-07-30 |
WO2010001110A2 (en) | 2010-01-07 |
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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 |
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17P | Request for examination filed |
Effective date: 20110214 |
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AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR |
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AX | Request for extension of the european patent |
Extension state: AL BA RS |
|
DAX | Request for extension of the european patent (deleted) | ||
17Q | First examination report despatched |
Effective date: 20110927 |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: H01H 37/40 20060101ALI20121017BHEP Ipc: G05D 23/275 20060101AFI20121017BHEP |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20130403 |