Muffle: types, uses, Price, characteristics …

November 2, 2021

If you want to know what a laboratory muffle is , you have come to the right place, since here we will explain in great detail everything you need to know about this equipment.

So that you can have all the information you need, we will explain what they are, what function they perform, the different types there are, how they are used and what care and precautions should be taken when using these laboratory tools.

What is a muffle?

The muffle is a tool that is used to handle high temperatures, which is why many see them as laboratory furnaces , which are intended for the firing of different materials and the melting of metals by means of the heat that they generate with thermal energy.

In laboratories it is very common that they are used to be able to calcine different substances, for casting, drying substances or for control processes .

In this way, the muffles are considered as closed chambers that are manufactured with refractory materials, being composed of a door through which the interior cooking chamber is accessed (as in the case of an oven), which has a window that allows you to observe what is happening inside.

In the upper part of the muffle there is a hole through which the gases of the inner chamber exit. Its walls are made of plates of thermal insulating materials that serve so that the muffle can fulfill its function.

Normally the muffle is used when some substances or objects need to be subjected to temperatures higher than 200 ° C. An important detail that must take into account is that the muffle only be used with refractory materials because it can reach temperatures up to 1200 ° C .

We must also bear in mind that there are different types of muffles , from fuel muffles, electric or based on other principles, although in all types of muffles we find an exterior cabinet, an interior cabinet, a door, temperature controllers and a panel. of control.

Which functions has?

As we have mentioned previously, the main function of the muffle is to be able to reach high temperatures in order to give it different uses within a laboratory. Among these uses we can highlight the following:

  • Used for cooking different materials.
  • Carry out heat treatments.
  • Do calcination tests.
  • Incineration of organic and inorganic samples.

These are some of the most common uses for these tools, although they can have many other uses within a laboratory.

What are its parts?

Among the different parts of a muffle, the most outstanding are the following

Control Panel

Depending on the type of muffle we are talking about, the type of control panel that the muffle has may vary. However, the most common elements within the control panel are:

  • Temperature control : this feature allows you to set the temperature to which you have to heat the muffle. Normally the type of control used by the flasks are usually PID, which makes the working temperature more exact within the flask. This is usually programmed so that there is no peak in temperature. This in order to damage the test that is heating inside the flask.
  • Timer : the timer is used to set a time for the muffle to operate. That is, the time that the equipment will operate as scheduled depending on the specific needs they have in the laboratory. For example, it can be programmed to be on for a period of 1 hour, 2 hours, 4 hours, 50 hours, etc., as well as it can be programmed for minutes or seconds.
  • Safety switch : this feature may change depending on the muffle manufacturer, but laboratory flasks typically have a safety switch on their door, which does the job of acting as a switch and cutting off the power supply when opened. In this way, exposure to the high temperatures to which the laboratory operator can be subjected is minimized.

Inner chamber

The internal chamber is undoubtedly one of the most important parts of the muffle, which must be built with alumina (aluminum oxide) and silica (silicon dioxide) , which are materials that are quite resistant to high temperatures, being perfect for this type of work.

The door of the muffle is made of this same material, so that it has the same resistance to high temperatures, achieving perfect cooking inside.

Also, in the upper part of the flask there is a hole where the temperature of the flask can be verified. This verification is done using an external thermometer. The hole also serves to release gases that may arise during the work of the tool.

Two elements can be found inside the inner chamber of the muffle:

Heating elements

These elements are those that fulfill the role of being able to serve as a source of heat inside the muffle. These elements are usually located in a strategic way so that the tool can heat homogeneously throughout the interior chamber.

THERMOCOUPLE

Also known as a sensor, it fulfills the job of sending an electrical signal to the electronic control of the muffle to indicate the temperature inside the tool, being able to level it as desired by the operators.

Types of Muffles

It is normal that different types of muffles can be found in laboratories or on the market, highlighting the electric ones and those that work with fuel.

Electric muffles

Electric flasks are the ones usually used when a maximum temperature of 1200 ° C is required. These are the most used and common within laboratories. Generally, these types of models are smaller in terms of size and capacity.

They are powered with 110 VAC or 220 VAC depending on the model and the heating needs that are had. They represent a high electrical consumption, so they are generally manufactured to be used with 220 VAC electrical networks that support said energy consumption.

Fuel muffles

Fuel muffles are used in cases where it is necessary to reach a temperature higher than 1200 ° C. The heat source for these models is supplied by natural gas or propane. Also, the heat source has to be separate from the cooking chamber.

Thus, the sample that is being heated will not be contaminated by the gas that feeds the equipment. These types of models are usually larger and offer a greater capacity.

Muffles with ramps

The muffles with ramps have a control that allows the temperature rise or fall time to be programmed . It has to be programmed with different temperature values ​​and given a certain sequence, as well as the time periods.

The function of the ramp muffles has a great advantage compared to the other models, since in these models some of the processes can be automated, which reduces costs and the time in which these processes are carried out. Thus, the user does not have to be modifying the values ​​manually every time it is necessary.

How do you use a flask?

The first thing that must be taken into account regarding the use of the flask is that it is intended to be used in laboratories, so under no circumstances is it recommended to use it outdoors, since it must be in environments with a temperature between 15 ° and 40 ° C , in addition to the fact that the environment in which it is located must have an average humidity of 80%.

For the proper use of this equipment, it is important to wear protective clothing, verify that it is well connected to its power source, place the samples to be processed and adjust the temperature or program it according to the specific needs you have.

In order to avoid burns, it is recommended to use gloves, an apron and all the protection that is necessary when working with high temperatures. Safety regulations within the laboratory must always be followed.

Precautions and cares

Previously we have already indicated some of the precautions that must be taken into account, so that you can have more information to make the best use of the muffle, these are some points of precaution that we recommend you follow:

  • It is necessary to periodically check the electrical connections of the laboratory.
  • An external cleaning must be done at least once a week . It is done using a damp cloth and a non-abrasive solution that is recommended for metal surfaces.
  • You do not have to use electrical multi-sockets to connect the equipment, nor do you have to use poor quality connections that can easily become hot.
  • The muffle has to be calibrated once a year to be able to fix any problems that may arise with the temperature.
  • Leave 15 centimeters of free space around the equipment , so that the heat can circulate and exit through the ventilation grills of the equipment. This is very important to avoid accidents.
Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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