US3270184A - Temperature sensitive control wires provided with transistors for electrically heated pads, blankets and the like - Google Patents
Temperature sensitive control wires provided with transistors for electrically heated pads, blankets and the like Download PDFInfo
- Publication number
- US3270184A US3270184A US333388A US33338863A US3270184A US 3270184 A US3270184 A US 3270184A US 333388 A US333388 A US 333388A US 33338863 A US33338863 A US 33338863A US 3270184 A US3270184 A US 3270184A
- Authority
- US
- United States
- Prior art keywords
- wires
- circuit
- heating element
- relay
- electrically heated
- 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.)
- Expired - Lifetime
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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
- G05D23/20—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
-
- 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
Definitions
- the two metallic control conductors are insulated from one another by a composition having a high negative thermal co-efficient of resistance.
- the arrangement above referred to has the disadvantage that the number of substances having a negative co-efiicient of resistance with change of temperature which can be used is small, and they do not become suificiently good conductors until the temperature is in the neighbourhood of 100 C.
- the object of the present invention is to provide control means of the kind here above described for electrically heated pads, blankets and the like which do not have the disadvantages above mentioned and which allows the choice of substances from a far greater range and to give a closer control of temperature than before.
- the invention consists in a temperature control means for electrically heated pads, blankets and the like as above described, characterised in having a circuit including one or more transistors which amplify the current passing through the sensitive material as a result of its increasing in temperature above the normal one.
- the invention further consists in a temperature control means as set forth in the preceding paragraph in which the electric circuit includes a manually variable resistor by means of which the temperature of the blanket or the like is adjustable.
- the invention still further consists in a temperature control means as set forth above in which the electric circuit includes a relay which is operated to open the heating circuit of the blanket or the like when the current through the transistor rises above a predetermined maximum value.
- the invention provides for the employment of a thermistor in the circuit of the relay to re-establish connection after a time lag, in order to maintain the temperature of the pad, blanket or the like, substantially constant.
- the accompanying drawing shows, by way of example only, one embodiment of the invention and comprises a transformer having a primary 1 suitable for use with the main domestic supply and a secondary 2 providing,
- the diodes 5 and 6 are connected by their cathodes to the emitter and collector respectively of the transistor 7, while the coil 8 of a relay is connected in parallel with the diode 6.
- the resistors 9 and 10 which may be of 5,000 ohms and 5,600 ohms respectively, form part of a bridge circuit, the point of junction of which is connected to the base of the transistor.
- the heating wires 11 of the pad or blanket or the like shown here in the form of a helix, are connected in series with the contacts 12 and 13 of the relay and are fed by current to the connectors 14. When the relay is energised the circuit is closed and the heating wires pass current.
- the temperature responsive element comprises a pair of parallel wires '15 and 16 which are separated from one another by thermal sensitive material 17.
- the wires 15 and 16 are connected to the ends of the resistor 9 in series with the adjustable resistor 18.
- the shunting effect of the temperature responsive element can be adjusted to give the effect required.
- the values of the resistors 9. and 10 are so chosen that as soon as current is supplied to the transformer the relay is energised and the heating Wires 11 begin to get hot.
- the current in the bridge is changed and the contacts of the relay open and the current of the heating wires 11 is interrupted.
- the temperature has fallen to a value as will cause the relay contacts to close the current is restored to the heating wires 11.
- variable resistor For example, if when the variable resistor is in the position of no resistance, and the resistance of the sensitive material 17, at the temperature of 30 C., falls to a value of 200 ohms, for the values of the resistors given, the relay contacts '12 and 13 are open and the heating current is interrupted. The consequent cooling of the pad Or blanket causes the material 17 to increase its resistance and the relay contacts again close.
- the wires 15 and 16 and the sensing material 17 are in the embodiment mentioned enclosed in the helix of the heating wire 11 and insulated therefrom, and consequently even if the blanket is inadvertently supplied with current when folded several times the sensing means will quickly be brought to a temperature which corresponds to a sufficiently low resistance to cause the relay contacts 12 and 13 to open.
- the sensitive material can be warmed also indirectly.
- the heating wire 11 is wound apart, on a core of insulating material, for instance of cotton, and the temperature control means may be distributed, if desired, only in some preferred zones of the blanket or the like.
- circuits of other kinds without departing from the scope and spirit of the invention which is that of amplifying, by mean-s of one or more transistors, the current which takes place through the sensing material in consequence of its increasing in temperature .above the normal one.
- the two wires and 16 can be disposed in a different manner from that shown in the drawing, for in stance both may be coiled on a core of sensible material but separated from one another by said material.
- An electronically controlled electrically heated blanket operable from a mains voltage source comprising a heating element adapted to be operated at mains voltage, a heat sensor comprising a pair of wires positioned in close proximity to one another throughout their length; a heat sensitive electrical conductor of relatively high electrical resistance at normal room temperatures in comparison with the resistance of said wires embedding the wires, and of negative co-efficient of electrical resistance, the heat sensor being substantially the same length as, and located .at least in close proximity to the heating element throughout its length, a relay having contacts which are in circuit with the heating element, a source of DC. potential of approximately 22 volts; and a transistor amplifier the input of which is connected to the pair of wires and the source of DC. potential and the output of which is connected to the relay, the circuit connected to the DC. source being electrically isolated from the circuit of the heating element.
- An electronically controlled electrically heated blanket operable from a mains voltage source comprising a heating element in the configuration of a helix and adapted to be operated at mains voltage; a heat sensor comprising a pair of wires positioned in close proximityof DC. potential may be connected; and a transistor amplifier having input terminals connected to the pair of wires and the terminals of the source of DC. potential; said amplifier having an output which is connected to the relay, the circuit at the DC. potential being electrically isolated from the circuit of the heating element.
- An electronically controlled electrically heated blanket for operation from an AC. main voltage source comprising a heating element in the form of a helix and adapted to be operated at main voltage, .
- a heat sensor comprising a pair of wires positioned in close proximity to one another and of uniform distance apart throughout their length and embedded in a rod-like heat sensitive electrical conductor of relatively high electrical resistance at normal room temperatures and of negative co-efficient of electrical resistance, the helix of the heating element being wound upon the rod-like conductor, the heat sensor being substantially of the same length as the heating element, an electromagnetic relay the contacts of which are in the circuit of the heating element, a source of DC.
- a Wheatstone bridge circuit the pair of wires being connected in series with a manually variable resistor as a shunt in one arm of the wheatstone bridge, and a transistor amplifier the input of which is connected between opposite junctions of the bridge and the output of which is connected to the energising coil of the relay.
- Heating and temperature control means as claimed in claim 1 in which a thermistor is connected in series with the contacts of the relay to delay the :re-establi-shrnent of the full heating current each time the circuit of the heating element is completed to limit the frequency of interruption of the element circuit.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Control Of Resistance Heating (AREA)
- Central Heating Systems (AREA)
- Thermistors And Varistors (AREA)
- Control Of Temperature (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1049/63A GB1005319A (en) | 1963-01-09 | 1963-01-09 | Temperature sensitive control wires provided with transistors for electrically heated pads, blankets and the like |
Publications (1)
Publication Number | Publication Date |
---|---|
US3270184A true US3270184A (en) | 1966-08-30 |
Family
ID=9715279
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US333388A Expired - Lifetime US3270184A (en) | 1963-01-09 | 1963-12-26 | Temperature sensitive control wires provided with transistors for electrically heated pads, blankets and the like |
Country Status (9)
Country | Link |
---|---|
US (1) | US3270184A (no) |
AT (1) | AT249819B (no) |
CH (1) | CH410222A (no) |
DE (1) | DE1515064A1 (no) |
ES (1) | ES295115A1 (no) |
FI (1) | FI40295B (no) |
GB (1) | GB1005319A (no) |
NL (1) | NL6400083A (no) |
NO (1) | NO118860B (no) |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3360693A (en) * | 1964-05-06 | 1967-12-26 | Indoheem N V | Switching circuit for an electrically heated blanket |
US3375477A (en) * | 1963-07-22 | 1968-03-26 | Kawazoe Toshinobu | Overheat detector for electric blankets and the like |
US3385956A (en) * | 1964-07-30 | 1968-05-28 | Mitsubishi Electric Corp | Protective device for electrically warming cloth |
US3385958A (en) * | 1965-05-10 | 1968-05-28 | Robert H Myers | Electric blanket |
US3437792A (en) * | 1967-10-31 | 1969-04-08 | Stevens & Co Inc J P | Electrical heating device with temperature control means |
US3445631A (en) * | 1966-03-14 | 1969-05-20 | Indoheem Nv | Safety system for an electrically heated blanket |
US3564203A (en) * | 1968-06-05 | 1971-02-16 | Hitachi Heating Appl | Automatic temperature control device for electric blanket |
US4272671A (en) * | 1978-09-15 | 1981-06-09 | Matsushita Electric Works, Ltd. | Temperature control system for electric surface heater |
US4278874A (en) * | 1978-08-24 | 1981-07-14 | Dreamland Electrical Appliances Limited | Heating circuits |
US4506137A (en) * | 1983-02-18 | 1985-03-19 | Meister Jack B | Temperature responsive control circuit for electric window de-fogger/deicer heater |
US4686427A (en) * | 1985-08-13 | 1987-08-11 | Magnetek, Inc. | Fluorescent lamp dimming switch |
US5036177A (en) * | 1990-05-16 | 1991-07-30 | Pagliarini Jr John A | Method for reducing hazards due to low frequency electric and magnetic fields |
US5204587A (en) * | 1991-02-19 | 1993-04-20 | Magnetek, Inc. | Fluorescent lamp power control |
US5474746A (en) * | 1991-09-09 | 1995-12-12 | Emitec Gesellschaft Fuer Emissionstechnologie Mbh | Catalyst carrier body for exhaust systems of internal combustion engines |
US20060138117A1 (en) * | 2004-12-07 | 2006-06-29 | Arturo Morgandi | Electric blanket/pad |
US20070103127A1 (en) * | 2005-11-04 | 2007-05-10 | Au Optronics Corporation | Multi-lamp driver with active current regulator |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB783883A (en) * | 1954-06-03 | 1957-10-02 | Antonio Negromanti | Improvements relating to electrically heated fabrics, particularly suitable for padsand blankets |
US3051815A (en) * | 1959-09-30 | 1962-08-28 | North American Aviation Inc | Phase controlled servo system |
US3068338A (en) * | 1960-12-22 | 1962-12-11 | Rca Corp | Thermostatically controlled circuits |
US3107285A (en) * | 1960-06-15 | 1963-10-15 | Nat Company Inc | Temperature control system |
-
1963
- 1963-01-09 GB GB1049/63A patent/GB1005319A/en not_active Expired
- 1963-12-26 US US333388A patent/US3270184A/en not_active Expired - Lifetime
-
1964
- 1964-01-06 DE DE19641515064 patent/DE1515064A1/de active Pending
- 1964-01-07 CH CH13264A patent/CH410222A/fr unknown
- 1964-01-07 AT AT8964A patent/AT249819B/de active
- 1964-01-08 NO NO151512A patent/NO118860B/no unknown
- 1964-01-08 ES ES0295115A patent/ES295115A1/es not_active Expired
- 1964-01-09 FI FI0036/64A patent/FI40295B/fi active
- 1964-01-09 NL NL6400083A patent/NL6400083A/xx unknown
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB783883A (en) * | 1954-06-03 | 1957-10-02 | Antonio Negromanti | Improvements relating to electrically heated fabrics, particularly suitable for padsand blankets |
US3051815A (en) * | 1959-09-30 | 1962-08-28 | North American Aviation Inc | Phase controlled servo system |
US3107285A (en) * | 1960-06-15 | 1963-10-15 | Nat Company Inc | Temperature control system |
US3068338A (en) * | 1960-12-22 | 1962-12-11 | Rca Corp | Thermostatically controlled circuits |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3375477A (en) * | 1963-07-22 | 1968-03-26 | Kawazoe Toshinobu | Overheat detector for electric blankets and the like |
US3360693A (en) * | 1964-05-06 | 1967-12-26 | Indoheem N V | Switching circuit for an electrically heated blanket |
US3385956A (en) * | 1964-07-30 | 1968-05-28 | Mitsubishi Electric Corp | Protective device for electrically warming cloth |
US3385958A (en) * | 1965-05-10 | 1968-05-28 | Robert H Myers | Electric blanket |
US3445631A (en) * | 1966-03-14 | 1969-05-20 | Indoheem Nv | Safety system for an electrically heated blanket |
US3437792A (en) * | 1967-10-31 | 1969-04-08 | Stevens & Co Inc J P | Electrical heating device with temperature control means |
US3564203A (en) * | 1968-06-05 | 1971-02-16 | Hitachi Heating Appl | Automatic temperature control device for electric blanket |
US4278874A (en) * | 1978-08-24 | 1981-07-14 | Dreamland Electrical Appliances Limited | Heating circuits |
US4272671A (en) * | 1978-09-15 | 1981-06-09 | Matsushita Electric Works, Ltd. | Temperature control system for electric surface heater |
US4506137A (en) * | 1983-02-18 | 1985-03-19 | Meister Jack B | Temperature responsive control circuit for electric window de-fogger/deicer heater |
US4686427A (en) * | 1985-08-13 | 1987-08-11 | Magnetek, Inc. | Fluorescent lamp dimming switch |
US5036177A (en) * | 1990-05-16 | 1991-07-30 | Pagliarini Jr John A | Method for reducing hazards due to low frequency electric and magnetic fields |
US5204587A (en) * | 1991-02-19 | 1993-04-20 | Magnetek, Inc. | Fluorescent lamp power control |
US5474746A (en) * | 1991-09-09 | 1995-12-12 | Emitec Gesellschaft Fuer Emissionstechnologie Mbh | Catalyst carrier body for exhaust systems of internal combustion engines |
US20060138117A1 (en) * | 2004-12-07 | 2006-06-29 | Arturo Morgandi | Electric blanket/pad |
US7180033B2 (en) * | 2004-12-07 | 2007-02-20 | Imetec Spa | Electric blanket/pad |
US20070103127A1 (en) * | 2005-11-04 | 2007-05-10 | Au Optronics Corporation | Multi-lamp driver with active current regulator |
US7274178B2 (en) * | 2005-11-04 | 2007-09-25 | Au Optronics Corporation | Multi-lamp driver with active current regulator |
Also Published As
Publication number | Publication date |
---|---|
ES295115A1 (es) | 1964-05-01 |
NL6400083A (no) | 1964-07-10 |
DE1515064A1 (de) | 1969-08-14 |
AT249819B (de) | 1966-10-10 |
FI40295B (no) | 1968-09-02 |
CH410222A (fr) | 1966-03-31 |
GB1005319A (en) | 1965-09-22 |
NO118860B (no) | 1970-02-23 |
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