A thermostat is device for maintaining a system (apparatus, machine, engine, etc.) at a relatively stable temperature. The first device was developed by Albert Butz in 1886 that gave birth to Honeywell. It allowed to order an air inlet door on a coal boiler to "regulate" its temperature. In 1906, Honeywell developed an already associated with a clock device, hence the birth of clock device (zone control thermostat).
Device has long been comprised of a bimetallic system which opens a circuit when the heat reached a certain stage and closed the circuit as soon as we descended below this temperature. In practice, it was as if there had been in fact two temperature setpoints neighboring thermal system with itself a certain inertia (similar to hysteresis in field of magnetism).
The effect of heater is switched on the room temperature in recent days is stored in a memory effect. When the indoor environmental conditions (eg open doors that are normally closed) or outdoors (by weather changes) change drastically, it will take some days before device optimally anticipates the need for heat.
Device is a switch that switches to a fixed or a temperature set. In latter case there is question of an adjustable device. This can be used, for example to maintain a certain temperature in a system by switching, such as the regulation of degree of energy source or drain. Something on or off The heart is a simple devices bimetal; it consists of two connected metal strips with different coefficients of expansion. Due to difference in thermal expansion when the temperature changes pulls the whole bent, so that at a certain temperature for a switch is converted.
A recent development is the electronic device with built-in clock. This allows the time-dependent temperature control in room, by which one can not forget to faucet at a lower temperature when it does not have to be in room. These can therefore save money. A thermostat is device designed to maintain a constant temperature for a given system through automatic adjustment.
The line of central temperature is the set point temperature and the differential d is the difference between the temperature which determines the state of off, and the one which determines the state of on. The time in on-off switching must be compatible with the equipment or fluid controlled: response times are too short can damage electrical equipment controlled (and generate noise on the power grid that does not comply with CE regulations on flicker) and are not therefore feasible with this type of adjustment. Device is therefore suitable to adjust the temperature of environments in which this varies slowly over time (civil environments, refrigerators ...).
In mechanical devices the sensitive element is a foil or a fluid in which the variation involves a thermal deformation and therefore is the same sensitive element which determines the state of switch. The sensor element can also be a bimetallic strip, which is constituted by two sheets of different materials joined together. Since the two materials have different expansion coefficients, a temperature change results in a curvature of foil which can then act directly as a switch.
In engines device opens the flow of cooling water with increasing temperature of cylinder head. In this case, the sensitive element is a wax and the opening temperature is between 70 and 90 degrees C. In these types device the sensitive element is typically a resistor whose resistance value is variable with temperature (for example an NTC thermistor), or a semiconductor device, (for example the IC LM31), which, inserted in an electronic circuit, controls the on-off state of a relay or other solid state device.
Device has long been comprised of a bimetallic system which opens a circuit when the heat reached a certain stage and closed the circuit as soon as we descended below this temperature. In practice, it was as if there had been in fact two temperature setpoints neighboring thermal system with itself a certain inertia (similar to hysteresis in field of magnetism).
The effect of heater is switched on the room temperature in recent days is stored in a memory effect. When the indoor environmental conditions (eg open doors that are normally closed) or outdoors (by weather changes) change drastically, it will take some days before device optimally anticipates the need for heat.
Device is a switch that switches to a fixed or a temperature set. In latter case there is question of an adjustable device. This can be used, for example to maintain a certain temperature in a system by switching, such as the regulation of degree of energy source or drain. Something on or off The heart is a simple devices bimetal; it consists of two connected metal strips with different coefficients of expansion. Due to difference in thermal expansion when the temperature changes pulls the whole bent, so that at a certain temperature for a switch is converted.
A recent development is the electronic device with built-in clock. This allows the time-dependent temperature control in room, by which one can not forget to faucet at a lower temperature when it does not have to be in room. These can therefore save money. A thermostat is device designed to maintain a constant temperature for a given system through automatic adjustment.
The line of central temperature is the set point temperature and the differential d is the difference between the temperature which determines the state of off, and the one which determines the state of on. The time in on-off switching must be compatible with the equipment or fluid controlled: response times are too short can damage electrical equipment controlled (and generate noise on the power grid that does not comply with CE regulations on flicker) and are not therefore feasible with this type of adjustment. Device is therefore suitable to adjust the temperature of environments in which this varies slowly over time (civil environments, refrigerators ...).
In mechanical devices the sensitive element is a foil or a fluid in which the variation involves a thermal deformation and therefore is the same sensitive element which determines the state of switch. The sensor element can also be a bimetallic strip, which is constituted by two sheets of different materials joined together. Since the two materials have different expansion coefficients, a temperature change results in a curvature of foil which can then act directly as a switch.
In engines device opens the flow of cooling water with increasing temperature of cylinder head. In this case, the sensitive element is a wax and the opening temperature is between 70 and 90 degrees C. In these types device the sensitive element is typically a resistor whose resistance value is variable with temperature (for example an NTC thermistor), or a semiconductor device, (for example the IC LM31), which, inserted in an electronic circuit, controls the on-off state of a relay or other solid state device.
0 comments:
Post a Comment