RU2625719C2 - Induction liquid heater - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: induction heater contains a cylindrical body with inlet and outlet branch pipes, a ferrimagnetic body for an induction coil with an electrical winding of insulated wires, a ferrimagnetic cover of the induction coil body. The body is made of a square tube, the body walls of the induction coil have a different thickness. There is a separating plate, which creates a labyrinth form of the fluid motion.

EFFECT: increasing the power of the heater.

2 cl, 4 dwg

Description

The invention relates to the electric power industry and can be used in heating systems, hot water supply, in technological processes for heating liquids, where it is required to provide a small temperature gradient between the heater and the heated liquid in flow mode or in a storage tank.

The prior art inventions and utility models of such a device and purpose.

US patent No.US 2010/0213190 dated 08/26/2010 "Flowing induction heater" for heating liquids, including an induction coil placed in a chamber with ferrimagnetic walls, along which pass channels for the movement of liquid. Liquid heating occurs from the ferrimagnetic walls of the inductor chamber. The device does not require additional electromagnetic shielding.

The design of the inductor chamber and the channels for fluid movement is made of thin-walled ferromagnetic pipes assembled coaxially on a common lid of equal thickness with pipes. For supply and drainage of water, there are inlet side and central outlet pipes. The device allows the ability to work in a wide frequency range from 50-400 kHz. To increase the heating efficiency, it is proposed to arrange flat ribs in the form of a spiral in the channels for the movement of the liquid, which increase the time and path of the liquid along the external heating ferrimagnetic wall of the inductor chamber.

The disadvantage of this device is the small thickness of the walls of the chamber and the cover of the inductor, which leads to a distortion of the shape of the electromagnetic field and, as a consequence, a decrease in the power factor (cos ϕ), and the use of the same type design in the frequency range with 8-fold overlap of the range will increase losses and generally lead to to low efficiency.

Patent for invention RU No. 2400944 C1, published September 27, 2010 “Vortex induction heater and heating device for rooms” for use in heating and water supply systems. Contains a cylindrical ferromagnetic capacity. Concentrically two metal pipes are attached to the end walls of the cylindrical container from opposite sides with the formation of a labyrinth exit for the heated fluid. It has an induction winding made of copper wire, enclosed in a sealed toroidal cylindrical body of insulating non-magnetic material, located in the center and coaxial with the pipes. The liquid is supplied to the tank through the pipe through the center of the cylindrical body of the winding.

The device has a number of disadvantages that actually reduce the declared performance indicators: the presence of an induction winding in the shell of only insulating material makes it very difficult to ensure electrical safety and tightness of the structure; the labyrinth scheme of fluid motion extends the path, but according to the above diagram, the electrical resistance of the inducted current increases and therefore the current decreases, which reduces the amount of heat generated; all elements of the device have the same thickness and complex configuration, which complicates the system of formation of the structure of the electromagnetic field, and therefore the choice of optimal parameters according to the declared performance indicators.

The closest analogue to the present invention is a patent for utility model “Induction heater of liquid media” RU No. 93597 U1, published 04/27/2010, which consists of a housing with inlet and outlet pipes, upper and lower covers and an induction coil, characterized in that the induction the liquid medium heater is equipped with a double-walled glass and an annular bottom mounted in the housing, the induction coil being placed in a sealed space between the glass walls. It is additionally indicated that the free space between the inner surface of the glass is filled with a dielectric heat-conducting material, and the number of coils in the glass can be from 1 to 6, the thickness of the walls of the glass is made of one thickness, and is determined by the formula given in the description.

With a simpler design than the previous analogues, this design also has disadvantages that reduce the efficiency of metal consumption, power factor and efficiency of converting electrical energy into heat. These include:

- a glass with upper and lower covers where the induction coil is placed is a hollow cylindrical toroid on the inner surface of which an electromagnetic field is formed with the help of an induction coil. The depth of penetration of the magnetic field into the material depends on the rate of change (frequency), the magnetic flux density and magnetic permeability of the material and, as a consequence, the shape and magnitude of the magnetic field. The electric field formed together with the magnetic field creates an electric current, which, in accordance with the Joule-Lenz law, causes the conductor to heat - the inner wall of the glass to the depth of penetration of the electromagnetic field. However, the surface area of the outside of the cup is larger than the surface of the inner wall of the cup, and therefore, the current density and conductivity will be different. This factor is not taken into account in this design, as a result of which the use of pipes of the same thickness for the walls of the glass increases the metal consumption, makes the structure heavier and reduces the power factor;

- the velocity of the liquid along the inner wall of the glass is higher than along the outer side, as a result of which the heat transfer coefficient on the duct will be insufficient to completely remove heat and reduce the temperature gradient between the heater and the heated liquid, which is important to reduce the formation of scale and heating of fuels liquids;

- the use of from 1 to 6 coils on a common core increases the dimensions along the length of the structure and increases the magnetic resistance to the flow generated by each coil, which leads to a decrease in power factor;

- if it is necessary to connect the heaters in series, for example, to obtain more power and power from a three-phase current source, it is necessary to use external connecting elements since the input and output pipes are asymmetrical and do not fit directly with each other;

- the vertical location of the heater with the lower inlet and lateral drainage of liquids requires the use of additional measures to remove air and vaporization products when the liquid is heated.

The present invention, on the set of essential features, differs from analogues in that the external housing of the heater is made in the form of a square tube, the thickness of the outer wall of the cylindrical body inside which the induction coil is placed, a separation plate is installed less than the thickness of the inner wall of the heater body, creating a labyrinthine form of fluid movement, which increases the flow rate and increases the turbulence of the fluid flow.

In order to increase the power of the heater, the heater bodies made of square tubes with dividing plates installed inside the bodies creating a labyrinthine form of fluid movement, are connected rigidly to the bodies of induction coils having walls of various thicknesses.

With a horizontal arrangement of heaters, natural air and vapor formation products are provided in the direction of fluid flow.

The proposed invention is aimed at solving the technical problem of creating a structure with properties that can be characterized by the following technical results:

- less metal due to the choice of the optimal wall thickness of the housing of the induction coil;

- by increasing the turbulence of the fluid along the heated surfaces of the cylindrical body of the induction coil, by means of the labyrinth passage of the fluid through the separation plate, the turbulent fluid flow creates better conditions for heat transfer, increases the efficiency and reduces the temperature gradient between the heated surface and the heated fluid, reduces the loss of scale and allows you to heat flammable liquids;

- the design of the heater with housings of square tubes, with housings of induction coils having walls of various thicknesses, with dividing plates installed inside the housings, are rigidly connected to each other, which allows to obtain high specific energy efficiency per unit volume of the heater.

These particular technical solutions are interconnected with the formation of a stable set of features to obtain the necessary technical result - a compact device that provides effective heating of the liquid in the claimed fields of application, with high efficiency and power factor, lower metal consumption and better maintainability.

The proposed technical solution is illustrated by the following drawings:

in FIG. 1 shows a general view of an induction fluid heater, side and front views;

in FIG. 2 shows a cross-sectional induction fluid heater in a square housing;

in FIG. 3 shows a sectional view of an induction fluid heater with three cases of square tubes;

in FIG. 4 shows the appearance of an induction heater with six cases made of square tubes.

The induction heater, shown generally in FIG. 1 includes a cylindrical body of square section 15, input 3 and output 2 nozzles for receiving and supplying heated fluid, shield 4 for connecting AC voltage to the induction coil and controlling the process of heating the fluid according to the specified temperature and pressure parameters, cover 6, front and rear supports 5.

The sectional induction heater shown in FIG. 2 consists of a cover 7, an induction coil with a winding of insulated wires 8, external 9 and internal 10 of the wall of the ferrimagnetic cylindrical body of the induction coil, a fixing bolt 11, process tubes for outputting the ends of the winding and installing an electrical control panel 12 , the sealing ring 13, the dividing plate 14 passing along the outer and inner sides of the cylindrical body of the induction coil 8. The cover 7 of the induction coil is made with by the shape of the end face of the cylindrical body of the induction coil. A cross-section AA shown in FIG. 2 shows a cylindrical body of square section 15, an inlet pipe 3, an outlet pipe 2. a separation plate 14, an inner thickened wall of a cylindrical body of an induction coil 10, an outer wall of a cylindrical body for an induction coil (9) and an induction coil 8.

The induction fluid heater shown in FIG. 3 in section, consists of three bodies made of square tubes rigidly fixed in the plane of the walls between each other in a vertical rack with the device between the flow-through housings, hermetically welded along the contour of the holes 16 and thus forming a common motion circuit of the heated fluid between the inlet pipe 3 of the lower case and outlet pipe (2) of the upper housing. A mounted 4 electric shield is installed on all three cases. In an embodiment, an external shield can be used.

In FIG. 4 shows a general view of an induction fluid heater, consisting of six heat pump housing square walls 15 connected in series, square 15, input 3 and output 2 pipes, an electric panel 4 and insulated panels for mounting electrical connections 17.

The proposed device operates as follows.

As shown in FIG. 2, the incoming liquid through the inlet pipe 3 is fed into the inner cavity of the heater casing and flows back into the outlet pipe 2 along the inner and outer walls of the cylindrical body of the induction coil through the separation plate 14. When combining the three heater bodies of FIG. 3, the liquid through the channels formed by the separation plates 14 along the walls of the housings of the induction coils through the flow openings 16 passes all three housing heaters and exits through the outlet pipe 2.

The heating of the liquid occurs from the ferrimagnetic walls (9, 10) of the cylindrical body of the induction coil of the heater, heated by an electric current by the induction winding of the induction coil. The frequency of the electric current is 50/60 Hz. Voltage 220/380 V.

To increase the efficiency of heat transfer, dividing plates are installed that create a labyrinth passage. By thus reducing by half the cross-sectional area for fluid passage and alternately changing the direction of fluid movement, increased turbulence is created, contributing to improved heat transfer between the heated walls and the heated fluid. The vertical movement of the fluid flow eliminates air and steam plugs and drains the fluid easily and quickly during maintenance and emergency situations.

The use of the walls of the housing of the induction coil with a thickness proportional to the density of the magnetic flux, allows you to provide the optimal penetration depth of the alternating magnetic field into the ferrimagnetic material of the walls and reduce the mass of the metal. Such a construction does not lead to distortion of the sinusoidal shape of the electric current, and therefore a high power factor is ensured and the active component of the current is increased, which in turn, in accordance with the Joule-Lenz law, increases the amount of heat released in the ferrimagnetic walls in proportion to the square degree of electric current . Also, to reduce magnetic resistance in the housing of the induction coil, the upper removable cover 7 is made with a groove of grooves to provide the most accurate and complete contact with the end surfaces of the inner 10 and 9 outer walls of the housing of the induction coil.

Thus, the present invention allows us to apply not only the simplest technological schemes of mass production, but also obtain the best results in terms of effectiveness in terms of reliability, durability, maintainability, power factors and efficiency.

The proposed invention was implemented and tested in practice using standard industrial equipment. Sealing elements, fasteners, as well as other auxiliary elements necessary for assembling the proposed induction heater are completed in accordance with the developed working drawings of the device.

The tests carried out with samples of 5 and 100 kW of power, in which design features that distinguish the invention from analogues were realized, showed results with an efficiency of 92-97 percent.

Claims (2)

1. An induction heater of liquids comprising a heater body with inlet and outlet nozzles, a ferrimagnetic case for an induction coil with an electric winding from insulated wires, a ferrimagnetic cover of the body of an induction coil that provides magnetic flux closure in the core of the induction coil, characterized in that the heater body is made of square tubes, the walls of the casing for the induction coil have different thicknesses, a dividing plate is installed inside the heater casing Ting, creating a labyrinth shape fluid movement. 2. An induction fluid heater comprising a heater body with inlet and outlet nozzles, a ferrimagnetic case for an induction coil with an electric winding from insulated wires, a ferrimagnetic cover of the induction coil body, characterized in that the heater bodies are made of square tube with induction coil bodies having walls of various thicknesses, with dividing plates installed inside the heater cases creating a labyrinthine form of fluid movement, rigidly connected are wondering among themselves.

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