Thermometers are measuring instruments, designed
with the purpose of taking the temperature through various scales and
mechanisms. At first one of the mechanisms used was expansion, since this is
one of the properties of certain materials to be able to expand in the presence
of heat, common among metals and various substances such as alcohols.
In the evolution of medical technology, the
thermometer represented an important advance since it allowed the measurement
of the temperature of the human body and accurately measure symptoms such as
fever, however now thermometers are not only used in medicine.
Just as it is possible to find different types of
thermometers, it is also possible to find different measurement scales for
these, some are Celsius, Fahrenheit, Kelvin and Reaumur. In the following
article we show you everything you need to know about thermometers, as well as
speed up your selection and purchase process with the purchase links of all the
models we have for you.
Thermometers,
characteristics, types and uses
As we have shown you previously, there are
different types of thermometers with their respective characteristics, uses,
advantages and disadvantages. Below we have listed each and every one of the
existing types, along with their purchase links and suggestions. Keep reading,
you might be interested.
1- Of
mercury
Mercury thermometers were created in the year 1714
by a physicist and engineer with the surname Fahrenheit, that's where the scale
measure used comes from. The Mercury thermometer consists of a bulb from which
a thin glass tube extends and inside is liquid Mercury, however the volume of
this metal is less than the total volume of the bulb.
It is necessary to inform you that the Mercury
thermometers are being replaced little by little by those that contain Gallium
or Galinstane inside. Meet some models here .
Advantage
·
Despite the toxicity of mercury, its use will
allow you to determine the temperature with greater precision compared to other
liquids.
·
Mercury thermometers tend to be much more
durable under duress.
·
Their prices are the lowest.
Disadvantages
·
If your Mercury thermometer falls, inhaling the
Mercury will turn it into a toxic vapor to inhale. Therefore, you must collect
it immediately using rags, gloves and masks as well as you must ventilate the
room.
·
Mercury has a low freezing point in relation to alcohol;
as a consequence it cannot be used in colder areas.
·
They are not recommended for use in babies and
young children.
2-
Laboratory
Laboratory thermometers are measuring instruments
with which the temperatures of different liquid or gaseous substances can be
determined, their accuracy and precision characterize them since they are
superior to other commercial thermometers.
In other words, laboratory thermometers are
designed to determine the magnitude of vibratory energy presented by the
molecules of a substance. This energy is manifested in heat, its intensity is
determined by a specific value of temperature. Check out some models here.
Advantage
·
The laboratory thermometer is characterized by
having a high sensitivity thanks to its fine bulb.
·
Temperatures between -10 degrees Celsius and 200
degrees Celsius can be determined, although there are some models that reach
approximately 357 degrees Celsius.
·
Models can be found that measure temperature in
Celsius, Fahrenheit, and even Kelvin.
·
They are designed to be resistant to temperature
fluctuations.
Disadvantages
·
Laboratory thermometers are designed for industrial
use.
·
If the thermometer is inserted into containers,
it should not touch the edges or the bottom, it could reflect the wrong
temperature.
3- Infrared
Infrared thermometers are equipment that allows the
measurement of temperature in a professional way. They stand out from the rest
for their ability to measure in the distance and without maintaining any
contact with the object to be measured.
Some measurements that should be taken into account
before acquiring one of these thermometers is to know the field of vision it
contains, the emissivity of the object and of course the precision of its
measurement. Some models available here .
Advantage
·
Infrared thermometers provide great reliability
and speed when measuring temperature.
·
It offers ease of use.
·
You do not need to get close to the object to
measure the temperature.
Disadvantages
·
If the surface of the object does not fill
completely the reading will be wrong, since the infrared thermometer takes into
account the surface of what is around the object.
·
Its price is very high.
·
Measurements with infrared thermometers cannot
be performed in the presence of liquids and vapors as the measurement is
altered.
4- Digital
·
Digital thermometers operate on the basis of
specialized electronic circuits and sensors, they are capable of measuring the
smallest voltage variations and translating them into digits within temperature
ranges, generally Celsius and Fahrenheit are used. Learn more here .
Advantage
·
Digital thermometers offer precision that allows
reliability when making measurements.
·
They have displays or screens in which the
temperature can be observed from afar, which makes the measurement simple and
attractive.
·
They are safe, resistant and light instruments.
Disadvantages
·
Measurements with digital thermometers can only
be made between -39 degrees Celsius and 357 degrees since its melting point
below this temperature makes Mercury solid.
·
Although they have great resistance, they can be
classified as fragile instruments, they break easily.
·
They are not designed to withstand sudden
changes in temperature.
·
For its use you must purchase batteries, once
these are used up it is difficult to find their replacements.
5-
Environmental
·
Environmental thermometers are those capable of
measuring the ambient temperature of an open or closed environment by means of
an internal sensor or an external probe, it can be used to control the
temperature in rooms and in turn outdoors since they are manufactured in a way
that they are resistant to the harshest conditions such as rain, wind, cold and
very high temperatures. Some models available here .
Advantage
·
It is possible to find them under two formats,
analog and digital.
·
Disadvantages
Accuracy can vary greatly between each type of
format.
6- Gas
This class of thermometers are very accurate in
their measurements, they have a very wide measurement range that includes from
-27 degrees Celsius and 1477 degrees Celsius, however their use is more
complicated, they are used mainly as normative instruments for the graduation
of other thermometers.
Gas thermometers are made up of an ampoule with gas
that can be Helium, Hydrogen and even Nitrogen according to the desired
temperature ranges and a pressure measuring manometer.
To carry out the measurements, the gas bulb is
placed in the environment whose temperature is to be measured, the column of
the manometer that usually contains Mercury is adjusted whose function will be
to give a fixed volume to the gas, the height of the Mercury column will
indicate the gas pressure, from this point the temperature can be calculated.
Learn more here .
Advantage
·
The measurement they offer is very accurate.
·
Its scope of application is very wide.
Disadvantages
·
Its high cost makes it the least purchased on
the market.
·
It is used only as a normative instrument for
the graduation of other thermometers.
7-
Resistance
·
Resistance thermometers are sensors that measure
temperature based on the way the electrical resistance changes in a conductor,
which can be metal, electrolyte or semiconductor in relation to its
temperature. The most popular of the thermometers is the Platinum one. Learn
more here .
Advantage
·
Temperature measurement by platinum resistance
thermometer is easier compared to gas thermometer.
·
These thermometers have a wide measuring range,
from 200 degrees centigrade to 1200 degrees centigrade.
Disadvantages
·
Resistance thermometer readings give it slow.
·
They are very sensitive.
8-
Industrial
Industrial thermometers work according to the
principle of gas expansion, by expansion of a bimetal or by the expansion of a
liquid, as well as being able to measure temperatures in wide ranges between
200 degrees Celsius and over 700 degrees Celsius.
These classes of thermometers are in danger of
extinction because the digital versions of these instruments have been
occupying their place for some time, due to their ease and simplicity of
handling and use. Some models available here .
Advantage
·
It is possible to find them under two
modalities, rigid bulb and capillary.
·
Temperatures above 700 degrees Celsius can be
measured.
Disadvantages
·
Industrial thermometers are calibrated to
measure very high Remote Reading thermometer.
9- Of
alcohol
Alcohol thermometers are glass capillary tubes with
a very small inside diameter that can be similar to the thickness of a hair,
they have very thick walls, at one end there is a dilation called a bulb that
is filled with alcohol.
Alcohol is a capable substance that expands or
contracts due to changes in temperature, thus increasing or decreasing
depending on it. A scale has been established on the tube that accurately marks
the temperature of the body evaluated. This type of thermometer was one of the
first to be created. Learn more here .
Advantage
·
The reliability of its measurement is high.
·
It is safer than Mercury thermometers.
Disadvantages
·
Alcohol thermometers are used to take the
temperature of the environment but not in people.
10- Kitchen
(For ovens)
Kitchen thermometers are very practical tools to
control the exact cooking point of food and even the temperature of oils for
the cooking process. Kitchen thermometers are specialists in determining the
exact point of meats and roasts, and with these the process of creating
candies, fried foods, chocolates and creams is improved.
Advantage
·
They offer great precision in their
measurements, therefore it is possible to avoid that the food is very dry or
hard and raw.
·
With the use of kitchen thermometers you can be
sure that you have eliminated all the bacteria that food may contain.
·
You can find different models such as meat,
digital, for ovens, and kitchen laser.
Disadvantages
·
They can only be used in food processing.
·
Its prices are high but it is justified with the
utility offered.
11- Glass
Glass thermometers are also known as rod
thermometers, they can generally include a metal sleeve of approximately 10 mm
in outside diameter and a ring at its upper end that allows the instrument to
be hung.
Advantage
·
These thermometers have great precision, between
+ - 1%.
·
The scratch of the scale on the thermometer is
totally resistant to acids and alkalis.
·
They are inexpensive instruments that measure
the temperatures of liquids and gases.
·
They do not need a source of energy for their
operation.
Disadvantages
·
Glass thermometers must be treated with care,
they must not be hit against any hard surface, since cracks may occur that
would affect their accuracy.
·
Its maximum reading is approximately 354 degrees
Celsius.
Thermometer
parts
Thermometers, regardless of their type, have
fundamental parts for their correct operation, below we will show you their
parts explicitly.
·
Bulb: It is considered the base of the
thermometer, it is located at the bottom, it is cylindrical or spherical
depending on its supplier, they are usually made of stainless steel but some
models can be made of glass.
·
Capillary: It is also known as a stem, it is the
tube through which the Mercury or any of the substances mentioned above flows,
it is inside the glass body of the thermometer and is in turn connected to the
bulb. The size of this affects the measurement.
·
Body: The body is the glass tube that covers the
capillary or stem, it is elongated and triangular in shape but the edges are
smoothed, improving its handling, they can usually measure between 20 and 30
cm.
·
Expansion compartment: This is the space found
above the stem, there the gas and air are deposited while the Mercury or the
substances in your thermometer rise.
·
Scale: This includes the marks found on the body
of the thermometer in which the temperature levels are indicated. Depending on
the type of thermometer it can be found in Fahrenheit or Celsius.
·
Valve: The valve works as a connection between
the bulb and the stem, this is the cause for the internal substance to drop
slowly, giving the person the necessary time to read the temperature reached.