Everything You Need To Know About Thermocouples

What is a Thermocouple:

A thermocouple is a tool for figuring out how hot or cold something is. It consists of two different metal wires that we joined together to make a junction. When we heat or cool the junction, we create a small voltage in the thermocouple’s electrical circuit. We can measure this voltage, and it shows how hot or cold the junction is. Before we go into further details, we are among the best thermocouple and cartridge heater manufacturer you can find online.

In theory, we can make a thermocouple from any two metals, but in practice, there are only a few common types. We need to make them, especially from alloys that help to make them more accurate and straight.

Almost any use can be made out of a thermocouple. They can be made to be strong, quick to react, and able to measure a wide range of temperatures.

How Do Thermocouples Work:

Simply said, a thermocouple is a sensor that is employed in the process of determining the temperature of an object. The construction of this kind of sensor consists of two separate metal wires that are connected together at one end. The thermocouples are then linked to a device that can read the readings from the thermocouple and take input from it. Readings of temperatures can be obtained throughout a broad spectrum, depending on the kind of thermocouple that was utilized to take the measurements. Get in touch with a reputable thermocouple manufacturer if you want to learn more about how thermocouples function.

The function of Thermocouple:

A thermocouple is just a sensor that is used to find out the temperature of something. This type of sensor is made of two different metal wires that are joined at one end. They are then connected to a device that can take a thermocouple input and measure the reading. Depending on the type of thermocouple you use, you can get temperature readings over a wide range of temperatures.

Types Of Thermocouples:

Probe Thermocouple:

What does a thermocouple mean? Now that we know what a thermocouple is and how it works, one of the most common questions is, “What is a thermocouple probe?”

A thermocouple probe is a type of sensor that is made in the shape of a probe. No matter if the sensor is a thermocouple type K, J, T, or N, they can all be made with the same size tube, housing, and construction. Check out our thermocouples sensor range to get an idea of how most of them are made.

What looks like a thermocouple? Because they are made in different ways, thermocouples have different looks. Even though a thermocouple is just two bare wires joined together, you can protect these wires and make them last longer by putting them in different structures.

Type K Thermocouple:

A type K thermocouple is made of Nickel-Chromium or Nickel-Alumel, which are two different kinds of metal. Type K thermocouples are the most common because they are cheap, accurate, reliable (depending on how they are made for your application), and can measure a wide range of temperatures.

Because they can measure a wide range of temperatures, Type K thermocouples can be used for a lot of different things. The highest temperature that stays the same for a long time is about 1100 Deg C.

The color of thermocouples with a plug or cable can be used to tell them apart. Type K is green in this case. The green leg of a cable is positive and the white leg is negative.

J Type thermocouple:

Then, what is a type J thermocouple? There are also a lot of Type J thermocouples. With a range of 0 to 600 Deg C, it has a smaller temperature range than a type K thermocouple. Iron and Copper-Nickel are the two different metals that make up the Type J. (Also known as Constantan). In terms of price, they are a lot like type K.

The plastics industry is one of the most common places where type J is used.

The color of thermocouples with a plug or cable can be used to tell them apart. Type J is Black in this case. The black leg of a cable is positive and the white leg is negative.

Advantages and Disadvantages of Thermocouples:

Advantages:

There are a lot of reasons why you might choose a thermocouple for your application.

Thermocouples can be used at temperatures that are very hot.

Thermocouples can be used in places that are hard to measure.

Thermocouples can be used over and over again.

The thermocouples respond quickly.

Thermocouples are accurate over a wide range of temperatures.

Thermocouples are very long-lasting.

Thermocouples can run on their own power, so they don’t need a source of current or voltage.

Thermocouples can handle a lot of shaking.

Limitations Of Thermocouple:

Even though a thermocouple probe is the best choice for many uses, there are some things you can’t do with it:

In a certain temperature range, thermocouples are not as accurate as RTDs.

Thermocouples can get out of sync over time.

When thermocouples are not well insulated, corrosion can happen.

The signals from thermocouples are not perfectly linear.

Applications Of Thermocouples:

Because thermocouples have so many benefits, we can use them in a wide range of situations, from controlling ovens to checking the temperature of planes, spacecraft, and satellites. Kilns, autoclaves, presses, and molds are all used in manufacturing to make things.

When we connect many thermocouples in series, they make a thermopile, which is more sensitive to temperature changes than a single thermocouple. we can use thermopiles to make devices that are sensitive enough to pick up on infrared radiation. In a radioisotope thermoelectric generator, we can use the heat from radioactive decay to power thermopiles, which we can later use to power space probes.

Disadvantages:

Here are some things that don’t work well with thermocouples.

It is possible for us to pick up stray voltage.

Since the output voltage is very low, we need to boost it.

It is important to have a cold junction and lead compensation.

It’s not a straight line.

Precautions for Using Thermocouples:

We collectively select thermocouples and protective sleeves based on the object’s upper-temperature limit, structure, and installation.

The position where we put the thermocouple into the furnace should represent its temperature.

We should insert the thermocouple as vertically as possible to prevent distortion at high temperatures.

We need to prevent air convection between the thermocouple and the furnace wall with asbestos rope or refractory mud.

The thermocouple junction box should be 200mm from the furnace wall. We should use a right-angle wire thermocouple to measure the salt bath furnace temperature.

The thermocouple’s installation position and direction should avoid strong magnetic fields, and we should ground the metal shell adequately to ensure measurement accuracy. In an electrode salt bath furnace, avoid the electrode.

We can twist the positive and negative thermocouple working ends 3 times.