From the article you will learn what a heating element is, for what purposes it is used, how it is connected. You will also learn about what design it has. In short, this is an electric heater, and the abbreviation itself is decrypted quite simply. This is a tubular electric heater. It bears such a name for the reason that often these elements are made in the form of ceramic, glass or metal tubes. And now let's take a closer look at all the components of this electrical appliance.
Element design
The article provides a diagram of the heating element. The most important component of any heater is the heater itself, made of nichrome filament, which is located along the entire length of the tube. The edges of the thread are fixed on the output studs. A nichrome thread has a certain resistance, when current begins to flow through it, it heats up and gives off heat to a metal or ceramic cage.
It should be noted that the material of which the tube is made must have a large current resistance. Therefore, it is made of alloys, which include constantan or nichrome. The resistance of the heating element depends on what kind of power the device needs to develop.
Calculation of heater parameters
According to Ohm's law, power is calculated, which is equal to the product of the current strength by the voltage of the electrical network. In other words, for a heating element to have a power of 1000 W, it is first necessary to calculate the current strength. There are two well-known parameters - power and voltage (in a household network - 220 volts). The current will be equal to the power divided by the voltage. If 1000/220, we obtain a current strength of 4.55 A.
In order to determine the resistance of the thread, it is necessary to divide the voltage by the current strength. As a result, we get the resistance of the TENA winding, expressed in ohms. More precisely, we divide 220 by 4.55 and we find that the resistance of the nichrome thread should be 48.4 Ohms.
It should be noted that resistance directly affects the power of the heating element. The lower the resistance value, the greater the power of the heating element. It is necessary to pay attention to the fact that almost all the power will be spent on heating the thread. Therefore, the efficiency of most TENs is almost equal to 100%. In other words, the more powerful the heating device, the faster and more it warms up.
Insulator and tube material
Between the tube and the nichrome thread is an insulator that can withstand very high temperatures. In order to make a tube for a heating element, it is necessary to choose materials that do not corrode. It is such tubular electric heaters that are most often used in industry and everyday life.
Prisoners in a glass tube are used, as a rule, in very aggressive environments, for example, in chemical laboratories in which it is necessary to heat various mixtures. But you can meet them in domestic heaters. As a rule, they are used in devices using infrared radiation. Ceramic tubes in heaters are used very rarely today.
Tube diameter
The diameter of the tubes can be any, but elements whose diameter lies in the range of 6-24 mm are very widespread. In addition to the fact that the insulator must have high insulating properties, it is necessary that it effectively transfers heat from the heating coil to the tube. Now let's talk about what is a heating element and how it works.
Power is supplied to the heater using the terminals that are located on the inserts with insulators. Terminals can be located both at one end, and at both. There are varieties of tubular electric heaters that are equipped with built-in protection in the form of a fuse. As a rule, such elements are installed in dishwashers or washing machines.
For heating air
For such heating elements, the temperature can reach 450 degrees. These tubular devices are used to heat air in domestic and industrial premises. Such heating elements are the basis for the manufacture of convectors, various designs of drying chambers, air curtains. These heaters have smooth or ribbed tubes. What is a heating element for air heating, we consider further.
The fins of these heaters are made of steel tapes that are attached to the tube. Due to the use of ribs, it is possible to increase the surface area of the element, therefore, the load on the nichrome thread is significantly reduced, and the resource of the element also increases. The heat transfer increases significantly.
Water heaters
When replacing the heating elements of a washing machine, you can see that his design is completely tight. Very often, such heating elements can be found both in washing machines, and in boilers, heating appliances. Water can be heated in them to a boiling point, and this is 100 degrees Celsius. If the volume of water is very large, block type devices are used. Quite often, together with the heater, a temperature controller is set for the boiler.
Using a thermostat, it turns out to disconnect the heating element from power when the liquid reaches the required temperature. As soon as the water cools down, the thermostat switches on the power again, and the spiral starts to warm up. Such heating elements are used for heating boilers, boilers, in washing machines.
Flexible type devices
Such designs have found application in systems with hot channels, in molds. They are convenient in cases where you need to give the contour in a hot channel system a certain shape. The sizes of electric heating elements can be any. A kind of flexible electric heating element that is familiar to almost every homeowner is a self-regulating cable for a warm floor. Such a heating heater is very often used in the manufacture of a room heating system.
A separate type of device is a cartridge, in which the terminals for connecting to a power source are on the same side. The length of the heating element can be a maximum of 3.5 m. The main difference from all other types of devices is that it has a compact body, most often made of stainless steel with leads.
The cartridge heating elements have a very high specific power, the heat from the heating element is transmitted both by convection and contact. Typically, such heaters are often used in industry for heating oil, various forms made of metal. Quite often, appliances can be found in the automotive industry, shoe, food, foundry.
Instrument Connection
In order to connect the device to an alternating voltage network, it is necessary to use the schemes given in the article. Be sure to install protection - circuit breaker. In addition, you can put a magnetic starter for switching the circuit or an electromagnetic relay. If you need to adjust the temperature, install a special controller - it is allowed to use both electronic and mechanical, working on the principle of a thermostat. Now you know what a heating element is and what its varieties are, and most importantly, have familiarized yourself with the connection diagrams.