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What is a thermostat? |
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| • Themostat |
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A device that stabilizes heat and temperature
The etymology for thermostat is a compound word combining "thermo" which means temperature or heat, and "stat" which means a stationary state. "Thermo" is how the word is pronounced in English, but in German it is pronounced "terumo" or "tamu". |
| • Purpose |
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(1) Temperature regulator (controller): Maintains a certain degree of temperature.
(2) Excess temperature rise protector (limiter/protector): Turns off the heat source when the temperature rises above a particular level.
(3) Temperature detector: Signals when the set temperature has been reached and causes another operation to occur.
These are the main purposes of the thermostat. |
| • Asahi's Thermostat is a bimetal thermostat. |
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The temperature switch senses the temperature through the bimetal and controls the electricity contacts (turning them on or off).
There are various kinds of devices for temperature control and measurement. |
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What are the principles of bimetal? |
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| • Bimetal |
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Two metals (a low expansion metal and a high expansion metal) are milled into a single sheet using a roller → Bimetal |
| • Bimetal is a compound word combining "bi" (a prefix meaning "two") and "metal." |
| • Pressurized bonding: Bonding by cool or hot rolling (molecular bonding). No adhesive is used. |
| • Materials: |
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High expansion metal contains an iron alloy (Fe) and nickel (Ni) with added substances Cr, Mn, and Mg; low expansion metal contains iron (Fe) and nickel (Ni) as the main materials for Invar (Ni35-Fe) |
| • Bimetal bends in one direction as the temperature rises and in the other direction as it falls. |
| • Force arises where the movement is controlled, and in the thermostat the set point pressure exerts a repelling force. |
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Types, structures and purposes of bimetal thermostats |
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| • Types and structures |
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| Laminated type: |
In this type, parts have been laminated together and fastened with a rivet, facilitating temperature variations in small increments. |
| Snap disc type: |
In this type, parts are contained in a covered case. It has a relatively large differential, and uses a low cost snap disc to prevent excessive temperature rises. |
| Protector type: |
This type is contained in a covered case, with, a snap disc integrated into the electric circuit for the detection and prevention of temperature rises or overcurrent situations. |
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| • Applications |
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| Home electric appliances: |
Home electric appliances: Kitchen goods (Computerized hot water kettles, coffee makers, ovens, hot plates, rice-cake makers, etc.)
Heating devices: Electric space heaters, electric heating pads, electric kotatsu (coffee-table type heaters with coverlets), panel heaters, electric mats, etc.)
Others: Ironing presses, hair dryers, vacuum cleaners, futon dryers, etc.) |
| Household goods: |
Lavatory seats, washlets (a seat-type of bidet incorporating seat warming and warm water irrigator), battery chargers, etc.) |
| Gas and oil: |
Bathtub boilers, water heaters, floor warmers, fan heaters, space heaters, etc.) |
| Others: |
Copy machines, automatic vending machines, automobiles, motorboats, marine jets, etc. |
| Industrial equipment: |
Construction tools, road signs, welding machines, etc. |
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