Induction heaters: structure and principle of operation, scheme of making your own hands
Induction heater can be installed in the apartment, this does not require any approvals and associated costs and hassles. The desire of the owner is enough. The connection project is required only theoretically. This is one of the reasons for the popularity of induction heaters, even despite the decent cost of electricity.
Induction heating method
Induction heating is heating by an alternating electromagnetic field of a conductor, placed in this field. Eddy currents appear in the conductor (Foucault currents), which heat it. In fact, it is a transformer, the primary winding is a coil, which is called an inductor, and the secondary winding is a tab or short-circuited winding. The heat is not supplied to the tab, and is generated in it by the most wandering currents. Everything, that surrounds it, remains cold, which is a definite advantage of devices of this kind.
The heat in the tab is distributed unevenly, but only in the surface layers and further by volume spreads due to the thermal conductivity of the tab material. Moreover, with increasing frequency of the alternating magnetic field, the depth of penetration decreases, and the intensity increases.
For inductor operation with higher frequency, than online (50 Hz), transistor or thyristor frequency converters are used. Thyristor converters allow you to get frequencies up to 8 KHz, transistor - up to 25kHz. Wiring diagrams can be found easily.
Planning to install heating systems in your own home or cottage, among other options on liquid or solid fuel, it is necessary to consider the option of using induction heating boiler. With such heating you will not be able to save on electricity, but no hazardous substances.
The principle of operation of the inductor
The main purpose of the inductor - the production of thermal energy through electricity without the use of electric heaters fundamentally different way.
A typical inductor consists of the following main parts and devices:
-
AC generator - a device for changing the mains frequency to a higher one, which is broadcast on the coil;
- inductor - coil, in which an alternating magnetic field is induced;
- heating element - a metal object, in which under the influence of an electromagnetic field eddy currents arise, which heat the conductor.
Heating device
The main elements of the induction heater for the heating system.
- Steel wire diameter 5-7 mm.
- Plastic pipe with a thick wall. The inner diameter is not less 50 mm and the length is selected according to the place of installation.
- Copper enameled wire for coil. Dimensions are selected depending on the power of the device.
- Stainless steel mesh.
- Welding inverter.
The procedure for manufacturing an induction boiler
option one
Cut the steel wire into pieces no longer than 50 mm. Fill a plastic pipe with chopped wire. ends muffle with wire mesh to prevent wire spillage.
At the ends of the pipe install adapters from the plastic pipe to the size of the pipe at the connection of the heater.
Wind the winding on the heater housing with copper enameled wire (plastic pipe). It will take about 17 meters of wire: number of turns - 90, the outer diameter of the pipe is close 60 mm: 3,14 X 60 x90 = 17 (meters). Specify the length additionally, when the outer diameter of the pipe will be known exactly.
Plastic tube, and now an induction boiler, cut into the pipeline in a vertical position.
Connect the boiler to the inverter, necessary fill the system with coolant and can be included.
option two
The design of the induction heater from the welding inverter in this option is more complicated, requires certain skills and abilities work with your hands, however, it is more effective. The principle is the same - induction heating of the coolant.
To begin with, you need to make the induction heater itself - the boiler. This will require two tubes of different diameters, which are inserted into each other with a gap between them close 20 mm. The length of the tubes from 150 to 500 mm, depending on the estimated power of the induction heater. You need to cut two rings according to the gap between the tubes and weld them tightly to the ends. The capacity of a toroidal form turned out.
It remains to weld into the outer wall of the entrance (lower) tube tangential to the body and top (weekend) the tube is parallel to the input on the opposite side of the toroid. The size of the tubes - the size of the pipes of the heating system. The location of the inlet and outlet pipes on the tangent, will ensure the circulation of the coolant throughout the boiler without stagnation.
The second step is to create a winding. Enameled copper wire should be wound vertically, passing it inside and lifting up the outer contour of the body. So 30-40 turns, forming a toroidal coil. In this version, the entire surface of the boiler will be heated at the same time, so, significantly increasing its productivity and efficiency.
Make the outer body of the heater from non-conductive materials, using, example, a large diameter plastic pipe or a banal plastic bucket, if its height is enough. The diameter of the outer casing must ensure the exit of the boiler pipes from the side. Ensure compliance with electrical safety rules throughout the connection scheme.
Separate the boiler body from the outer body with insulation, can be used as a bulk thermal insulation material (expanded clay), and tiled (izover, manipulate, etc.). This prevents heat loss to the atmosphere from convection.
It remains to fill the system with your coolant and connect the induction heater from the welding inverter.
such a boiler absolutely does not require intervention and can work 25 and more years without repair, as there are no moving parts in a design, and the connection scheme provides for the use of automatic control.
option three
It, vice versa, the simplest heating option housing, carried out with their own hands. On the vertical part of the pipe of the heating system you need to choose a straight section at least a meter long and clean it from the paint with sandpaper. Then insulate this section of pipe 2-3 layers of electrical fabric or dense fiberglass. Then wind the induction coil with enameled copper wire. Carefully insulate the entire wiring diagram.
It only remains to connect the welding inverter and enjoy the heat in their homes.
Note a few points.
- It is undesirable to install such a heater in living rooms, where people are most often. The point is, that the electromagnetic field propagates not only inside the coil, but also in the surrounding space. To make sure of that, it is enough to use an ordinary magnet. You need to take it in hand and go to the coil (boiler). The magnet will start to vibrate noticeably and even stronger, the closer the coil. So it is better to use a boiler in a non-residential part of the house or apartments.
- Installing the coil on the pipe, make sure, that in this part of the heating system the coolant naturally flows upwards, so as not to create a countercurrent, otherwise the system will not work at all.
You can offer many options for the use of induction heating in the home. Example, in the hot water supply system you can refuse to supply hot water at all, heating it at the outlets of each tap. However, this is a topic for separate consideration.
A few words about safety when using induction heaters with a welding inverter:
- to ensure electrical safety it is necessary to carefully insulate the conductive elements designs on all scheme of connection;
- induction heater is recommended only for closed heating systems, in which the circulation is provided by a water pump;
- it is recommended to place the induction system at a distance of at least 30 cm from the walls and furniture and in 80 centimeters from the floor or ceiling;
- to ensure the operation of the system you need to equip the system with a pressure gauge, emergency valve and automatic control device.
- to install device for venting air from the heating system to avoid air congestion.
The efficiency of induction boilers and heaters is close to 100%, at the same time it is necessary to consider, that power losses in welding inverters and wiring, anyhow, return to the consumer in the form of heat.
Before you start making an induction system, see technical data of industrial designs. This will help determine the initial data of the homemade system.
We wish you success in creativity and work for yourself!
