Electromagnetic heat tube
Technical field
The present invention relates to a kind of electromagnetic induction heater, be specifically related to a kind of Electromagnetic heat tube, it is applicable to heat non-magnetizer.
Background technology
Induction heating is exactly utilize the mode heating of metal magnetic conductor of electromagnetic induction or a kind of method of non-magnetizer (as water, conduction oil, gas), the heating being applied to industrial circle is started in 20 beginnings of the century, due to it have firing rate fast, in internal batch heating and efficiency is high, product quality is high, almost pollution-free, the series of advantages such as easily to be automated, developed rapidly.Induction heating technique is used widely in industries such as casting, melting, heat treatment, heat forged.Along with the progress of semiconductor power device, from thyristor to STL, IGBT, induction heating develops from low frequency to high frequency, by the medium that heats also by the future development of metal guide magnet (high temperature) to non-magnetizer (water of low temperature, conduction oil, gas), induction heating product also by industry to civilian future development, as electromagnetic induction water heater, electromagnetic oven etc.
Non-magnetizer induction heating with the Faraday's law of electromagnetic induction for principle, utilize helical load coil or plane vortex coil on metal magnetic conducting cylindrical shell, produce eddy current by alternating current and then heat occurs, and realize the heating of non-magnetizer by the heat exchange of metal magnetic conducting cylinder inboard wall interface and the non-magnetizer in it.
The subject matter that the heater utilizing helical load coil or plane vortex coil and metal magnetic conducting cylindrical shell to form exists is: coil exposed is outside at heater, and be difficult to realize shielding, periphery exists electromagnetic radiation, causes interference to the person and miscellaneous equipment; The heat integrated distribution produced is in the metal guide magnetic cylinder section of winding around, and heat skewness causes local overheating, forms local and tie carbon when particularly heating conduction oil.The heat efficiency is relatively low.
Current, electrothermal tube is used to one of common component heating water, oil, gas, due to the defect of electrothermal tube itself, the energy conversion efficiency of electrothermal tube only has 70-85%, and the heat efficiency is low, and energy loss is large, when particularly utilizing electrothermal tube heating water, easily at surface scale, electrothermal tube is very easy to bad, and maintenance cost is high.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of Electromagnetic heat tube, and it is linear, tubular electromagnetic induction electro-heat equipment, and the present invention utilizes linear, tubular structure to realize induction heating; Achieve electromagnetic-radiation-free, energy conversion efficiency be high, firing rate is fast, uniform heat distribution, structure is simple, dependable performance, is applicable to the heating of the non-magnetizers such as water, oil, gas.
In order to solve the problems of the technologies described above, the present invention is achieved through the following technical solutions:
Electromagnetic heat tube, its structure is as follows: current-carrying conductor is high temperature wire, is arranged with metal magnetic conducting body outside current-carrying conductor, between current-carrying conductor and metal guide magnet, be filled with insulating barrier, the left end of current-carrying conductor is connected with the first binding post, and the right-hand member of current-carrying conductor is connected with the second binding post.
The high temperature wire that above-mentioned current-carrying conductor adopts multiply parallel is formed.
The cross section of above-mentioned current-carrying conductor is circular.
The cross section of above-mentioned current-carrying conductor is quadrangle, triangle, ellipse or polygon.
Above-mentioned metal guide magnet is tubular structure.
Above-mentioned current-carrying conductor is uniform along central axis in metal guide magnet tubes.
The outer wall shape of above-mentioned metal guide magnet is linear, U-shaped or spirality.
The material of above-mentioned metal guide magnet is conveying seamless steel pipe, stainless steel tube or steel metal tube.
The outer face of above-mentioned metal guide magnet and be provided with encapsulant between the first binding post and the second binding post.
Owing to adopting technique scheme, the present invention is made to have following technical characterstic and technique effect:
The present invention changes the traditional structure that induction heating must use coil, and Electromagnetic heat tube of the present invention is that current-carrying conductor is placed in the structure of metal guide magnet inside to realize electromagnetic induction heating.During traditional non-magnetizer electromagnetic induction heating, its scheme is wound around current-carrying coil on tubular metal magnetic conductor, and non-magnetizer is placed in cylinder inside.The solution of the present invention is then that current-carrying conductor is placed in tubular metal magnetic conductor inside, and Electromagnetic heat tube is immersed in non-magnetizer.Current-carrying conductor flows through alternating current, around it, produce alternating magnetic field, the metal guide magnet being placed in magnetic field produces inducts inductance gesture thus produces eddy current, generates heat due to the resistance characteristic of metal guide magnet self, the heat sent passes to by the non-magnetizer (as water, oil, gas etc.) heated.
Electromagnetic heat tube power of the present invention is applied widely, and single tube power reaches from several kilowatts to hundreds of kilowatts.By choosing different current-carrying conductor sectional area and mating the metal guide magnet of respective diameters, insulating barrier and Electromagnetic heat tube length, obtain the inductance value of Electromagnetic heat tube, and then determine the power output of single Electromagnetic heat tube.
Electromagnetic heat tube electromagnetic-radiation-free of the present invention.It is inner that current-carrying conductor is placed in tubular metal magnetic conductor, and electromagnetic field is limited in the space of metal guide magnet completely, effectively prevents interfere with electromagnetic field to be leaked to space outerpace, makes the person and miscellaneous equipment not by electromagnetic interference.Metal guide magnet is heater and electromagnetic shield, achieve heating and the dual-use function shielded, and structure is simple, easily manufactured, thoroughly solves a difficult problem for electromagnetic induction heating electromagnetic interference.
The Electromagnetic heat tube heat efficiency of the present invention is high.Be immersed in during work in heated medium, current-carrying conductor does not need cooling, and the line loss heating of current-carrying conductor is also used effectively.The present invention heats non-magnetizer (as water, oil, gas body) by induced current, achieves the completely isolated of current-carrying conductor and heat medium, and structure is simple, safe and reliable.
Electromagnetic heat tube of the present invention compares with existing electrothermal tube: electrothermal tube heater element is in centre, the heat sent passes to heated medium through insulating barrier and protection tube, heat transfer path is far away, thermal resistance is large, efficiency is low, heating element and the heated medium temperature difference large (200-500 DEG C), easily fouling causes protection tube local overheating and damages when the water is heated, and useful life is short; Electromagnetic heat tube heater of the present invention is metal guide magnet, directly contact with heated medium, heat transfer path is short, thermal resistance is little, efficiency is high, and heater and heated medium have a narrow range of temperature (50-80 DEG C), and heater produces dither and non-scaling under alternating current effect, long service life, maintenance cost is low.
Electromagnetic heat tube electric heating of the present invention is greater than 98%, improves 5-10% than existing electromagnetic-induction heating method, improves 10-25% than electrothermal tube.
Accompanying drawing explanation
Fig. 1 is the fundamental diagram of electromagnetic heating tube of the present invention.
Fig. 2 is that the master of electromagnetic heating tube of the present invention looks sectional structure schematic diagram.
Fig. 3 is that the A-A of Fig. 2 is to sectional structure schematic diagram.
In figure, 1, current-carrying conductor, 2, insulating barrier, 3, metal guide magnet, the 4, first binding post, the 5, second binding post, 6, encapsulant.
Embodiment
Embodiment 1
As shown in Figures 2 and 3, Electromagnetic heat tube current-carrying conductor 1 of the present invention is high temperature wire, its cross section is circular, the best high temperature wire adopting multiply parallel is formed, its cross section the best is circular, metal magnetic conducting body 3 is arranged with outside current-carrying conductor 1, insulating barrier 2 is filled with between current-carrying conductor 1 and metal guide magnet 3, metal guide magnet 3 is tubular structure, it is uniform that current-carrying conductor 1 manages interior central axis along metal guide magnet 3, the left end of current-carrying conductor 1 is connected with the first binding post 4, the right-hand member of current-carrying conductor 1 is connected with the second binding post 5, the outer face of metal guide magnet 3 and be provided with encapsulant 6 between the first binding post 4 and the second binding post 5.Metal guide magnet 3 adopts the defeated employing seamless steel pipe of fluid to be prepared from.
Manufacturing process of the present invention is penetrated by current-carrying conductor in metal guide magnet tubes, its gap location by powder packed machine fill insulant equably, then with machine for shrinking by caliber shrinking, make insulating material closely knit, making current-carrying conductor and air exclusion, there is not skew and brushes up against tube wall in center.Like this, ensure that the fail safe of Electromagnetic heat tube, improve useful life, the heat efficiency can reach more than 98%.
The outer wall shape of above-mentioned metal guide magnet 3 is linear, and this can not be used for limiting protection scope of the present invention.
Embodiment 2
Electromagnetic heat tube of the present invention, current-carrying conductor 1 be quadrangle, outermost layer is metal guide magnet, and current-carrying conductor 1 is uniform along metal guide magnet 3 central axis, filling insulating barrier 2 between current-carrying conductor and metal guide magnet, metal guide magnet 3 adopts the defeated employing seamless steel pipe of fluid to be prepared from.The outer wall shape of metal guide magnet 3 is U-shaped, and this can not be used for limiting protection scope of the present invention.Other structure is identical with embodiment 1.
Embodiment 3
Electromagnetic heat tube of the present invention; current-carrying conductor 1 be triangle; outermost layer is metal guide magnet; current-carrying conductor 1 is uniform along metal guide magnet 3 central axis; filling insulating barrier 2 between current-carrying conductor and metal guide magnet; the outer wall shape of metal guide magnet 3 is spirality, and this can not be used for limiting protection scope of the present invention.Other structure and material is identical with embodiment 1.
Embodiment 4
Electromagnetic heat tube of the present invention, current-carrying conductor 1 be oval, outermost layer is metal guide magnet, and current-carrying conductor 1 is uniform along metal guide magnet 3 central axis, and filling insulating barrier 2 between current-carrying conductor and metal guide magnet, other structure is identical with embodiment 1.The outer wall shape of above-mentioned metal guide magnet 3 is linear, and metal guide magnet 3 adopts the defeated employing seamless steel pipe of fluid to be prepared from stainless steel tube material and is prepared from.This can not be used for limiting protection scope of the present invention.Other structure is identical with embodiment 1.
Embodiment 5
Electromagnetic heat tube of the present invention, current-carrying conductor 1 be polygon, outermost layer is metal guide magnet, and current-carrying conductor 1 is uniform along metal guide magnet 3 central axis, and filling insulating barrier 2 between current-carrying conductor and metal guide magnet, other structure is identical with embodiment 1.The outer wall shape of above-mentioned metal guide magnet 3 is spirality, and metal guide magnet 3 adopts steel metal tube material to be prepared from.This can not be used for limiting protection scope of the present invention.Other structure is identical with embodiment 1.
Above some execution modes of the present invention are illustrated, but these execution modes just propose as an example, and not intended to be limits scope of invention.The execution mode of this innovation can be implemented with other various form, can carry out various omission, displacement, change within a range not departing from the gist of the invention.These execution modes and distortion thereof are included in scope of invention and purport, and comprise the invention recorded in detail in the claims and with in the scope of its equalization.
Operation principle of the present invention is as follows:
As shown in Figure 1, the present invention supposes that the length of metal guide magnet 3 is the radius that L is far longer than current-carrying conductor 1, when current-carrying conductor flows through alternating current, produces the identical alternating magnetic field of frequency around, according to Biot-Savart law approximate representation is:
In formula: B
1magnetic flux density in-current-carrying conductor;
B
2the magnetic flux density of insulating barrier between-filling current-carrying conductor and metallic magnetic conductor;
The alternating current that I-current-carrying conductor flows through;
μ
0the magnetic permeability of-vacuum;
R1-current-carrying conductor radius;
The inside radius of R2-metal guide magnet.
On metal guide magnet inside radius R2, the magnetic flux density at P point place can be expressed as by formula (2):
From formula (3), the magnetic flux density at P point place is directly proportional to the alternating current I that current-carrying conductor flows through, with metal guide magnet inside radius R2 inverse ratio.When R2 is constant, increases alternating current I and can improve magnetic induction density B.It is uniform that postulated point P moves the magnetic flux density in a small amount in the rectangular element dS that surrounds of dr along radial direction, equals a magnetic induction density B at P place
p, so the magnetic flux passed through of rectangular element dS can be expressed as:
From formula (4), in magnetic flux and its magnetic induction density B at metal guide magnet inwall R2 place
p, the length L of rectangular element dS and width dr is directly proportional.When structure one timing of Electromagnetic heat tube, by improving magnetic induction density B
pincrease magnetic flux.
If alternating current is sinusoidal variations, then magnetic flux
also in sinusoidal variations, formula (4) is rewritten as:
Metal guide magnet is in above-mentioned alternating magnetic field, because the effect of alternating magnetic field produces induced electromotive force e, thus produces eddy current I
g, add that metal guide magnet has resistance characteristic and generates heat itself.The induced current of the larger generation of induced electromotive force e is also larger, and the power that metal guide magnet obtains is also larger.According to maxwell's electromagnetic equation, its induced electromotive force e can be expressed as:
Its effective value is: E=4.44fN
2 , so the inductive loop joule's heat energy closely produced at metal guide magnet inner surface additional, can be expressed as:
In formula: the Joule heat (J) generated when Q-induced current flows through metal guide magnet;
I
g-effective current of inducting (A);
The equivalent resistance (Ω) of R-metal guide magnet;
T-heating time (s).
The heat that metal guide magnet produces passes to non-magnetizer (as water, conduction oil, air) makes it heat.
As the above analysis: induced potential E and magnetic flux
, frequency f is directly proportional, in order to obtain necessary induced potential, can obtain by improving supply frequency.Same heating effect, frequency is higher, required magnetic flux
and the electric current I in induction coil just can reduce.In addition, metal magnetic conducting body section is larger, so under same magnetic flux density, by metal guide magnet
also larger, so the power that induced potential E and metal internal induction obtain is also larger.
Result of the test of the present invention is as follows:
System forms: 50KW superaudio power supply, Electromagnetic heat tube of the present invention, tank, temperature instrumentation etc.
Testing program: Electromagnetic heat tube of the present invention bends to definite shape and places in the sink, and water in heating water tank, applies certain power with superaudio power supply, measures the Electromagnetic heat tube efficiency of heating surface.
Inductance value directly determines electromagnetic induction heating rated power, tests the relation of inductance value and Electromagnetic heat tube length.Test shows: inductance value is directly proportional to the length of Electromagnetic heat tube, has good linear relationship.As shown in table 1.
The relation of table 1 inductance value and length
Electric conversion efficiency result of the test is as table 2, and the computing formula in table is as follows:
The ratio of specific heat of effective power=water quality x water holds the rear water temperature of x(test-initial water temperature)
Electric conversion efficiency=(active power/input power) x100%
Table 2 electric conversion efficiency test data
Electromagnetic heat tube electric heating of the present invention is greater than 98%, improves 5-10% than existing electromagnetic-induction heating method, improves 10-25% than electrothermal tube.
When the current-carrying conductor 1 in embodiment 1 can select 16mm
2high temperature wire, metal guide magnet 3 select the Electromagnetic heat tube of boiler seamless steel pipe, insulating barrier 2 Ceramics pipe, and when length is 16m, with 20KHz superaudio Power supply, input power is 20KW, active power 19.6KW, and conversion efficiency is 98.0%.