The Function of a Thermos – Hello, Sinaumed’s friends , I’m sure you are already
familiar with a kitchen tool called a thermos. The reason is, almost every household keeps
these devices. You can see for yourself what the function of a thermos is in general, namely as
a tubular container or bottle for storing hot water.
Thermos is a household appliance that has many advantages. In the past, thermos flasks were
only used to store hot water. Today, thermos flasks have been improved many times to make them more
practical and can be carried anywhere.
For example, mothers will often carry a small thermos of hot water with them to make milk for their babies.
Unfortunately, very few people know the role and function of a thermos as a container for drinking
water.
Since this kitchen appliance keeps water hot, mothers can use it to make milk for their children on the
move. But did you know that each part of this thermos has its own function?
Thermos function
1. The function of the outer glass wall
The thermos has an outer glass wall, which functions to prevent radiant heat transfer. So the
heat from outside that enters the thermos is reflected back, so that the cold water contained in the thermos
is maintained at a temperature.
2. The thermos lid function
The thermos lid has a shape that is like a blockage and functions to prevent water and air from coming in
and out of the thermos. In other words, the thermos lid can prevent heat transfer by convection
and conduction.
3. The function of the glass wall
Can we also see the function of the flask from the inside of the glass? In addition to the
outer glass wall, the flask also has an inner glass wall. The function of this section is to
prevent heat transfer so that the wall is not absorbed.
4. The function of the protective glass wall
A protective glass wall is located on the outside of the tank. The function of this section is
to isolate heat between the air around the flask and the glass tube on the appliance. Having an
outer insulation layer prevents you from getting too hot when you want to pour hot water from the
thermos.
5. Function of the Cup Holder Rubber Part
The next part of the thermos is the rubber cup holder, which has the function of keeping the bottle or
glass in the bottle fixed and unchanged. This thermal rubber is the bottom of the thermos
design.
6. Vacuum or Vacuum Function
The vacuum or vacuum inside the vessel prevents heat transfer from outside the vessel and inside the
vessel, and isolates heat. The absence of a medium in this vacuum prevents heat transfer by
conduction and convection.
In short, if the function of the tank in the vacuum section is to limit the possibility of heat loss from
inside or heat entering from outside into the tank. The vacuum is the center of the
flask.
The flask is actually made of double-glazed glass, with a vacuum between the walls or the middle.
Then on one of the walls there is a layer of silver, which traps heat so that radiation does not
occur and is not absorbed by the wall.
7. The Outside of the Thermos
The outside of the thermos has a tube shape made of plastic or stainless metal material that is sturdy and
can protect the inside of the thermos. Now the outside of the thermos is available in various
colors and patterns to give it an aesthetic impression.
History of the Thermos
The invention of the thermos has made significant changes since 1904. Steady technological advances and constant
development of new products have helped keep the thermos at the forefront of the industry for almost a century.
The flask was invented by Sir James Dewar in 1892, a scientist at the University of Oxford, the first “thermos”
to be produced commercially in 1904, when a German two-glass blower founded GmbH Thermos, the public held a
naming contest for “servant jar” (vacuum flask) , after which the Munich people named it “thermos” from
the Greek word “Therme” which means “hot”.
In 1907, Thermos GmbH sold the trademark rights to the bottle to three independent companies:
The American Thermos Bottle Company of Brooklyn, NY; Thermos Limited from Tottenham, England;
Canadian Thermos Company Limited of Montreal, Canada. Thermos became so popular and
known after being brought by a number of famous expeditions, including:
- Lieutenant. EH “Shackleton’s Journey to the South Pole”,
- Robert E. Peary’s “Journey to the North Pole”,
- Colonel Roosevelt “Expedition to Mombasa and into the heart of the African Congo” with
Richard Harding Davis. - The Wright Brothers “Airplane and Zeppelin”
This flask is praised worldwide for its revolutionary design. In 1909, this flask won the
“Grand Prize” at the Alaska Yukon Pacific Show and was honored for seven other exhibitions around the
world.
In 1911, Thermos made a technological breakthrough by producing the first glass filling machine.
So far, the thermos is famous for its vacuum glass technology in the world.
The growth in the popularity of the flask was extended by the production of glass making machines.
In 1923, the company introduced a 24 liter “blue jug” and a large rice flask called the “Jumbo
Jug”.
A new type of vacuum insulated double-walled Pyrex® glass tank was newly designed in 1928 and had a
capacity of 24 gallons. It became very popular in 1928 and 1929 for ice cream and fish
freezers, shortly before the advent of commercial refrigeration.
When World War II broke out in Europe in 1939, almost all the herbs stored in Britain were limited due to
use by soldiers for war. Meanwhile, in the US, the thermos company that played a role in
supplying thermos for wartime needs was “The American Thermos”.
At that time, more than 98% of the production of flasks was used for military purposes and atomic energy
laboratories. Although the war ended in 1945, the flask’s popularity continued to grow.
By 1957, the vacuum flask was almost universally recognized for use in food and beverage. In
addition, thermos products are also very useful for the needs of the scientific, medical and industrial
world.
They have been used in a variety of instruments for measuring electrical power, aircraft climb rates,
detecting oil deposits and recording weather conditions. And has been used to transport rare
tropical fish, store and transport plasma, serum, bone, tissue and insulin.
In 1966, the world’s first thermos with the name stainless steel vacuum was introduced.
This product will change the way food or drink is kept cold or hot around the
world.
In 1971 thermos products were exported to more than 100 countries. 1985 was a successful year for thermos with
the introduction of the coffee machine “The Coffee Butler” . This vacuum insulated
glass carafe hit the market around this time and became one of the top household products in North
America.
Tips for Choosing a Good and Right Thermos
Is the function of a thermos really useful in everyday life? Especially when traveling, you
can still get drinks with temperatures that are still hot or still cold. This makes the thermos
a popular household appliance and a must have, for example a portable stove.
Due to the large number of thermos products on the market, you may feel confused about which thermos to
choose. because there are thermos products that leak quickly, as a result the hot water storage
process will be disrupted.
So based on that, you have to apply some tips in choosing a thermos. The first thing is to pay
attention to the material used to form the device earlier. In general, the thermos itself is
made using various materials.
Starting from glass, plastic, to stainless steel . Of course, it would be better if you
choose a thermos made of glass or stainless steel, because materials like these tend to have a good
ability to retain temperature.
As there are many flasks in circulation, their sizes become more varied. some are mini sizes,
for example 200 milliliters and some are up to three liters in size. Therefore, you need to
adapt it to your daily needs.
Also, don’t forget to consider the thermos function according to your needs. Because over
time, thermos can not only be used to delay heat. But you can also use it to withstand cold
temperatures.
However, some of the flasks that were scattered turned out to have only one ability. For
example, being able to withstand only heat or only being able to withstand cold temperatures.
So according to that, you must adjust it according to your needs.
It’s not uncommon for people to think that having a high price is good. Because the outer
appearance of the thermos does not guarantee the quality of the thermos in maintaining the water
temperature.
In addition, sometimes brand flasks are counterfeited so that brands that are known for their good quality turn
out to be bad.
Quoted from Vacuum Flask.rangdong.com , there are three types of flasks, namely glass bottles,
stainless steel bottles, and plastic bottles. Each type has its own advantages and
disadvantages.
Glass thermos is safe for health, keeps heat stable and preserves milk, coffee, tea without mixing odors.
However, in general, glass flasks are expensive. Some glass bottles are not impact-resistant.
For example, consider saving for a trip to Lebaran.
If you need both, then choose a thermos that can be used at the same time to delay cold and hot
temperatures so that the function of the thermos is much more flexible. Then don’t forget to
pay attention to the size of the thermos you need.
It is undeniable that today’s thermos is indeed one of the kitchen thermos that is needed by every
household. Using a thermos, you can also use it and easily carry warm drinks or cold drinks on
the go.
- Smell Check
Before buying, remember to smell the thermos, if there is a bad smell, it means that the material in the
thermos is not good. So it’s better not to buy it.
- Check the Weight of the Flask
You might be tempted to buy a thermos because it’s lightweight so you don’t have to carry it around.
However, a thermos that is too light is not made properly or the material is not good, besides that
a thermos that is too light cannot retain heat for a long time or can only retain heat for about 1-2
hours.
- Endurance Test
A good thermos can retain heat for a long time so that every component fits perfectly. The
bottle cap must be tight and the cap rubber must be good silicone.
Because the silicone material has few molecules, it mixes with the drink when pouring. In
addition to not sealing, silicone bacteria can build up on the lid of the hot water tank and cause an
unpleasant odor that is a potential health hazard.
How a Thermos Works
According to the exchange theory of Henry Prevost Babbage (1824 – 1918), a colder object always absorbs
heat waves from the other until they are both at the same temperature. Based on this theory,
hot or cold tea in a thermos will lose heat or absorb heat from its place. However, temos is
designed to be able to block three paths of heat transfer: conduction, convection, and radiation.
The flask is made of double glass, the space between the two walls and one of the walls is covered with a
glossy coating (silver was used here). In this flask there are two glass walls, each of which
is polished. The inside is polished so that hot water is not absorbed by the walls.
While the outside of the glass wall is polished and coated with silver in order to prevent heat
transfer by radiation.
What do you do with a vacuum? Vacuum is used here to prevent heat transfer by convection.
Does the lid have a function? Obviously, yes, the thermos lid here is made of
insulating material, the goal is to avoid heat transfer by conduction. The operating principle of a thermos
is actually very simple.
This flask uses an adiabatic material. Ideally, this adiabatic material inhibits the
interaction between the system and the environment. There is no displacement of the system on
the ship with its environment. Hence no heat exchange. By using this adiabatic
material, the thermos can maintain the temperature of the water it contains.
Thermos Parts
1. Close the Cork (Bottle Cap)
This unit has the function of closing the bottle cap after the thermos is full of water. This
cap has the effect of preventing heat transfer by conducting conduction. So the thermos lid can
prevent water and air from escaping from the thermos.
2. Glass Inner Wall
We may not realize that a flask has an inner lining. This wall has the effect of preventing
heat transfer of hot water so cold water is not absorbed. It is intended that heat is
distributed unscathed and conducts heat to the outside.
3. Exterior Glass
This section serves to prevent heat transfer by radiation. The heat from the outer wall of the
glass that enters the balloon is reflected to the outside of the balloon so that no heat enters.
4. Vacuum Space (Vacuum)
This section has the function of maintaining and limiting the possibility of losing heat contained in the
thermos. According to the Encyclopedia Britannica , these voids prevent heat
transfer from the interior and exterior walls leading to insulation. Therefore, this
process becomes important in vacuum bottles.
Therefore, the thermos is responsible for minimizing heat loss by conduction and convection, but not by
radiation. The plug is made of a mixture of aluminum, glass, plastic and cork, so it conducts
electricity fairly well.
The inside of the thermos is made of aluminum covered with glass while the outer protective layer of the
thermos is made of plastic and cork with the aim of keeping the temperature in the thermos constant and
unchanged. Then the vacuum (vacuum) in the thermos acts as an insulator to maintain the water
temperature.
Application of Thermodynamics to Flasks
Of course, there are still many applications of thermodynamics in our lives. Another example
of the application of thermodynamics can be found in the flask. The application of the first law of
thermodynamics is also found in the flask, which uses an adiabatic material, thus preventing the exchange of
heat between the system and the surroundings and vice versa, so that there is no decrease in
temperature.
A thermos is also an example of an isolation system that is fairly easy to find. How heat
works is put into a thermos and cannot get out because it is blocked by the shiny white glass.
The reason why all of our bottles have glossy white glass inside is because compared to dark
colors, white absorbs less heat.
In addition to heat-resistant glass, heat is also prevented by an air gap between the tube and the glass,
then an air gap between the tube and the wall is prevented, because air is a poor conductor of electricity.
hot. Eventually, it gets blocked again by the outer layer of the plug or whatever we touch and see
which is usually plastic or metal.
By using this adiabatic material, the thermos is able to maintain the temperature of the water inside.
Hot water that has entered the thermos does not cool quickly.
Author: Ziaggi Fadhil Zahran