Thermastat
A heating system without a thermostat ... it seems kind of silly, when you think about it, doesn't it? If you don't have the ability to control the temperature inside your home, then there isn't much point to having a heating system. All right, that's probably an exaggeration. After all, it would still be better to have a heated home than to freeze. However, having a thermostat connected to your home's heating or even cooling system is probably considered by most everyone to be a necessary component of the system itself. Thermostats are great little devices that enable us to keep temperatures within a certain range so we never get too hot or too cold. Thermostats can automatically turn on a heating system when temps drop down too low in winter, or they can turn on the air conditioning when the place gets just a little too tropical for comfort. There are two main types of thermostats. These are mechanical and digital, with many digital thermostats having the capability to be programmed, which is a great way to control temperatures and save energy and money when members of the house are gone during the day. Today, thermostats are used in homes, cars, and any place that needs temperature control.
History
Here's a wild piece of information. According to known records of history, the earliest version of a thermostat-type temperature control device dates back to 1620! It's true. It was constructed by Dutch inventor, Cornelius Drebbel (who incidentally also built the first navigable submarine). Drebbel built a mercury thermostat that was actually used to regulate the temps of chicken incubators. Modern thermostats were developed a couple of hundred years later in 1830 by chemist Andrew Ure, inventor of the bi-metallic thermostat in order for textile mills to have a way to control temps and keep them at a steady level. The first electric room thermostat was invented by an inventor from Wisconsin, Warren Johnson, in 1833. Inventor Albert Butz is credited with inventing the first electric thermostat with a patent in 1886.
How does it work?
Some (mostly older) thermostats are controlled by a mercury switch and a thermometer coil, known as a bimetallic strip. This bimetallic strip is made up of a pair of long strips made of different types of metal that were attached to each other. As they are different types of metals, they expand at different rates which causes the thermometer inside to coil and uncoil tighter. When the uncoiling happens beyond a certain point, this causes it to bump into the mercury switch, making it switch over and the mercury bead inside to slide to one side, closing the circuit and turning on the heater. (A pretty cool effect that almost looks like an old Mousetrap game!) Digital thermostats contain a mechanism called a 'thermistor.' This is a kind of resistor, which is an electrical part that is designed specifically to resist the flow of electrical current. While most resistors provide a fairly unified level of resistance at all temperatures, the thermistor is designed to have its resistance change as the temperature changes. Digital thermostats contain a small computer that monitors how much resistance the thermostat's inner thermistor is creating and utilizes the data to then calculate current temps in the room. Many of today's digital thermostats are programmable. They contain built-in clock mechanisms that allow users to program varied values for different times of the day.
Car thermostats work a little differently. They contain a brass and copper body that fits between a water neck and radiator hose, with the center of the thermostat containing a kind of gate mechanism that opens when it reaches the desired temperature. Inside the thermostat also is a ball of wax in its center that remains solid when it is cold. When the coolant from the engine reaches the desired temp, this ball of wax liquefies, and this opens the gate mechanism. Then, when open, the thermostat sends the coolant through the radiator to be cooled. When the engine is shut off for a while, the thermostat cools, and the wax ball is again turned into a solid.
It's hard to think of how uncomfortable homes, cars, and other places would be without the ability to control temperatures. Although they've been around for hundreds of years, thermostats have proven to be enduring mechanisms whose usefulness doesn't seem to be decreasing with time.
History
Here's a wild piece of information. According to known records of history, the earliest version of a thermostat-type temperature control device dates back to 1620! It's true. It was constructed by Dutch inventor, Cornelius Drebbel (who incidentally also built the first navigable submarine). Drebbel built a mercury thermostat that was actually used to regulate the temps of chicken incubators. Modern thermostats were developed a couple of hundred years later in 1830 by chemist Andrew Ure, inventor of the bi-metallic thermostat in order for textile mills to have a way to control temps and keep them at a steady level. The first electric room thermostat was invented by an inventor from Wisconsin, Warren Johnson, in 1833. Inventor Albert Butz is credited with inventing the first electric thermostat with a patent in 1886.
How does it work?
Some (mostly older) thermostats are controlled by a mercury switch and a thermometer coil, known as a bimetallic strip. This bimetallic strip is made up of a pair of long strips made of different types of metal that were attached to each other. As they are different types of metals, they expand at different rates which causes the thermometer inside to coil and uncoil tighter. When the uncoiling happens beyond a certain point, this causes it to bump into the mercury switch, making it switch over and the mercury bead inside to slide to one side, closing the circuit and turning on the heater. (A pretty cool effect that almost looks like an old Mousetrap game!) Digital thermostats contain a mechanism called a 'thermistor.' This is a kind of resistor, which is an electrical part that is designed specifically to resist the flow of electrical current. While most resistors provide a fairly unified level of resistance at all temperatures, the thermistor is designed to have its resistance change as the temperature changes. Digital thermostats contain a small computer that monitors how much resistance the thermostat's inner thermistor is creating and utilizes the data to then calculate current temps in the room. Many of today's digital thermostats are programmable. They contain built-in clock mechanisms that allow users to program varied values for different times of the day.
Car thermostats work a little differently. They contain a brass and copper body that fits between a water neck and radiator hose, with the center of the thermostat containing a kind of gate mechanism that opens when it reaches the desired temperature. Inside the thermostat also is a ball of wax in its center that remains solid when it is cold. When the coolant from the engine reaches the desired temp, this ball of wax liquefies, and this opens the gate mechanism. Then, when open, the thermostat sends the coolant through the radiator to be cooled. When the engine is shut off for a while, the thermostat cools, and the wax ball is again turned into a solid.
It's hard to think of how uncomfortable homes, cars, and other places would be without the ability to control temperatures. Although they've been around for hundreds of years, thermostats have proven to be enduring mechanisms whose usefulness doesn't seem to be decreasing with time.