DE1074782B - Low frequency induction heater - Google Patents

Description

GERMAN

There is known a low frequency induction heater in which the metallic insert to be heated insertable into the axial channel of the induction heating coil through one end of the channel and in which a core serving to concentrate the magnetic flux in the inside of the Heating coil located channel can be introduced.

The invention also relates to such an induction heater. It is based on the task to allow such an adaptation of the heating effect to the respective needs that the temperatures of the metal insert at various points along the axis of the induction heater Can be sized at will.

For this purpose, according to the invention, a section of the coil is provided with several distributed over its length Pick-up taps are provided, and the core for bundling the magnetic flux is in different Positions adjustable along this section. By themselves, these two characteristics are not intended to be protected be. Because it is no longer new, the induction heating coil made up of several arranged in series Assemble individual coils, which can be switched on and off as required, thus creating the longitudinal distribution of the magnetic flux is changed.

It is useful to have a heat-insulating body between the one for bundling the magnetic flux serving core and the insert to be heated inserted in order to dissipate the heat from the insert to prevent in the core. For the same purpose, a heat insulating body between the be inserted from the core facing away from the end of the insert and a carrier of this insert.

In a preferred embodiment of the invention, the coil has fewer turns per Unit of length on that section or along the section of the coil on which the consumer taps are provided. This means that the axially adjustable core is at that end of the coil is provided on which the width of the turns is increased.

Various other advantages and objects of the invention will become apparent from the description below and the drawings can be seen; in these shows

Fig. 1 is a partially sectioned front view of a preferred embodiment of the invention,

Fig. 2 is a partially sectioned side view of the device shown in Fig. 1,

Fig. 3 is a partial cross-sectional view of a layered Kerns, which forms part of the invention taken along line 3-3 in Fig. 1,

Fig. 4 is a perspective view of the exploded Parts for the thermal insulation and support of the operation,

Low frequency induction heater

Applicant:

Magnethermic Corporation,
Youngstown, Ohio (V. St. A.)

Representative: Dipl.-Ing. M. Licht, patent attorney,
Munich 2, Sendlinger Str. 55

Claimed priority:
V. St. v. America January 10, 1955

Bruce E. Mc Axthur, Youngstown, Ohio (V. St. A.),
has been named as the inventor

Fig. 5 is a perspective view of a thermal

a5 insulation body.

A coil 1 made of an electrically insulated conductor has several consumer taps distributed over its length 2 provided. It is mounted between fixed clamping plates 3 and 4, which are mutually hold opposite ends. They clamp the coil tightly between them, their isolated Windings are close to one another along the coil. To the plates 3 and 4 in this position to each other to clamp, suitable tie rods 5 protruding through them are provided, which on the plate 3 are attached in order to be able to attract them against the plate 4.

About the tie rods 5 sleeves 6 are pushed from electrical insulating material, which prevent the tie rods 5 come into contact with the spool or other parts along its course. the Sleeves 6 are slightly shorter than the distance between the plates 3 and 4, so that they do not Interfere with the clamping process between the plates and the coil.

A sleeve 7 extending along its central tunnel is mounted inside the spool 1, in FIG which the block or insert to be heated can be inserted. This sleeve 7 is preferably made of a non-magnetic substance. If necessary, it can be a difficult-to-melt material Act..

In the example shown, this is insert or open end of the coil designated with 8, the opposite

909 728/452

3 4

The overlying or closed end is denoted by 9, a reducing or oxidation-preventing gas

net. At the closed end 9 of the coil extending through the carrier 20 are introduced into the sleeve 7

the tie rods 5 through the plate 4 and the can. This is an anti-oxidant or

Discs 10 and 11 through. The sleeve 7 is reducing atmosphere during the heating

Slidably received by the disks 10 and 11. 5 process in the sleeve 7 maintained. The gas

Sleeves 12 are attached to tie rods 5 and are inserted into carrier 20 through a suitable inlet

extending from the top or outer surface of 30 is inserted into cap 29.

Washer 10 up to suitable clamping nuts 13 on the To keep the sleeve 7 coaxial with the bobbin,

Rods 5 extend. As a result, the compression during the upper end of the coil can be along the sleeve

from the nuts 13 via the sleeves 12 on the Schei- io is movable relative to the clamping plate 4, so that it

Ben 10 and 11 and thus transferred to the plate 4, the clamping process does not interfere with an annular sleeve 31

to press the plate 3 against the plate 4. attached to the disc 16 it extends over

As a result, the plates 3 and 4 at the ends are a short distance axially into the sleeve 7 at the end 9

the coil in the clamped position and the insulated winch coil in. The sleeve 31 "extends" approximately

fertilize in sufficiently close contact with one another along 15 over the whole core and fits into the sleeve 7 tele-

the coil held so that their clashing like a scope with movement play into it,

is prevented. _ _ The end 9 of the spool and the sleeve 7 are so different

A holder 14 is attached to the sleeves 12 and arranged so that the escape of gas and the ingress

guided by them axially movable to the coil. This enters the sleeve 7 from outside air

Holder 14 consists of an inner sleeve 15 and 20 is prevented. When the establishment is in upright

at the ends attached annular disks 16 is operated position, as shown here, and

and 17, which are at a fixed axial distance from each other than gas helium or another gas, which is lighter

be held by the sleeves 18. These pods are used as air, the bottom of the can

18 are left axially open on the sleeves 12 assigned to them. When the establishment

movable. 25 in a position other than vertical or with a

With the help of compression springs 19, which is operated between the heavy gas, a sealing ring

Disc 17 and the carried by the rod 5 or a closure made of asbestos or other suitable

Nuts 13 are clamped, the carrier 14 is provided netem material at the end 8 of the coil

be held and pressed elastically against the disc 11, as will be described later here,

resiliently on the clamping plate 4. 30 The core 22 can be moved axially in the coil in different

On the holder 14, a core carrier 20 can be moved along the sleeve 7 to different positions so that

brings that he is in different positions axially to one and all these positions he can with the help of

can be asked. This core carrier 20 has the holding device 14 and the spring 19 of any force

Form of a sleeve which telescopically resiliently resist the sleeve, which against it in the axial direction

15 of the holder 14 fits into it. The sleeve is along 35 in the direction of the coil and in the direction of the end 9

slotted on one side and acts with a clamping bolt 21. He can absorb such forces without bumps and

provided so that it fits tightly around the sleeve or the block and itself in the original position.

Bring back core support 20 in different axial setting positions.

the same can be clamped. In this way accordingly any magnetic

the core carrier 20 is axially adjustable to the coil 1, 40 advancement of the block in the sleeve along the coil

by resiliently intercepting its position with respect to the holder 14 firmly against the core when the block

is placed, and he can in various positions against the core 22 abuts so that the block under

be moved along the coil, the shock absorption back in its correct, before

Carrier 14 is held in each of these positions. specific location is pushed.

On the carrier 20 is a layered core 22 45 This is a safety precaution which is particularly

attached, which preferably alternating layers is very desirable if the device

made of steel or ferromagnetic material 23 and operated with the axis of the coil located horizontally

Layers with high thermal conductivity 24, as is shown. Should the core be on a smaller block length

for example copper. The layers should be adjusted as they emerge from the introduced block.

speaks through 50 parallel to the magnetic field lines, for example because the core is being readjusted

the core. 22 forgot about the larger block length, then

At the top of the layered core 22 is one the core can be inserted through the longer block into the

Arrangement for dissipating the heat attached. Sleeve 7 are pushed in, causing the coil

This arrangement can consist of a longer tube and the feeding device from severe impact

one or more turns 25 exist, which are 55 protected and stresses,

press against the outer surface of the core 22. The mounting of the holder 14 by the springs 19

This pipe has a water inlet 26 and one also ensures an effective seal against it

Outlet 27, both of which extend to the outer end of the gas escaping from the sleeve 7.

of the carrier 20 extend and with the feed and order the blocks or bars in the coil

To feed the return line of an external cooling system 60 is a corresponding piston 32 with a

are bound .. The inlet port of the feed line is axially adjustable piston head 33 arranged so that

denoted by 28. he a pre-determined route into the operational

The outer end of the carrier 20 is immersed through one end 8 of the coil.

Cap 29 completed, through which the pipe between the piston head 33 and the adjacent parts 26 and 27 to the outer connections at the 65 end of the block and between the core 22 and stretch with which they are thermally sealed to the cooling system at the adjacent end of the block are. insulating cushions 34 and 35 switched to

For reasons discussed later, the carrier 20 is to be concealed from heat losses at the ends of the block and open at the lower end so that gases can wrestle out of it. The heat induced in the core can with can escape into the interior of the sleeve 7, so that 70 help of cooling water can be discharged when this

is required to keep the core at low enough Temperatures works.

The pads 34 and 35 are attached to the core 22 and the piston 33, respectively.

As shown in Fig. 4, the thermal insulation 34 can be in the form of a disk 36 of thermal insulation Have fabric in a container 37 made of stainless steel with an upper wall 38, a lower Wall and a side wall 39 is located.

The container 37 is provided with narrow, diametrically opposite radial slots 41, which extends over the end walls, over the middle of the insulating body and up to the outer boundaries extend. These slots essentially lift induced in the container 37 Stream on.

The piston, 33 is also, with radial slots 42 Mistake. If desired, as previously stated, an annular seal 43 or an asbestos pad can be used be inserted between the piston 33 and the cushion 34. This seal is made of insulating material and has such a large diameter that it seals the lower end of the sleeve 7. The pillow 34 is provided with lugs 43 a in order to attach it to the piston 33.

As shown in Fig. 5, the pad 35 is constructed quite similarly. It has slots 44 and lugs 45, which clamp the layers of core 22 together. Because the invention is particularly advantageous to use with alternating currents of about 25 to 60 Hz and voltages of about 50 to 460 V, it is suitable for the usual mains voltages and mains frequencies.

The width of the turns measured in the longitudinal direction of the coil should be 8 to the end of the insert in the middle upper plane of the bobbin. Accordingly, the coil, starting at end 8, wound with a few turns of a conductor of uniform cross-section, so that this first Turns are all the same width. The thickness of the conductor measured in the radial direction may be between wide limits fluctuate. A little further along the ■ coil, a conductor with a larger cross-section will appear used. This latter conductor can have the same radial thickness as the turns in the first section have or have a different thickness, but is dimensioned wider. The following groups of turns of the conductor are chosen so that their width measured in the longitudinal direction of the coil after the closed coil end progressively grows up to the transverse center plane of the coil. Each group of turns is therefore wider than the group of turns adjacent to the open coil end. the End parts of the successive groups of turns can be connected to the ends of the next adjacent Groups are electrically connected by soldering or similar means. If so desired the conductor can consist of a water-cooled tube.

A modified version of the coil which has some of the effects described above, but in different ways Aspect does not work as satisfactorily, can be used in certain cases. In this variant, the conductor is of the same cross-section and, starting with the end of the insert, where the 6g Turns are relatively close together, and continued up to the middle transverse plane of the coil, the turns get a progressively larger distance, the further away they are from the end of the insert are. Insulating material of limited compression.

speed is used to completely bridge the gap between the individual turns. The windings with their insulation placed in between are firmly clamped so that the windings, which are held at a distance from one another by the insulating material, immovable in the longitudinal direction of the coil are.

A graphic representation of this variant should be dispensable.

As already mentioned, the device is particularly suitable for the use of blocks of different Length, with special tasks occurring that are not different when heating blocks of the same length necessarily yielded.

If you wanted to z. B. try to create a uniform over the entire length and cross-section of the block Force line density by adding enough windings and taps, - those along the Coil are distributed below the top of the block, then the coil would be too long fail to bring about a good concentration of the magnetic flux in the block, since the windings cannot be crowded together in a number of different places, as is different for them long blocks is attached. Accordingly, the core 22 is used instead to provide a to achieve good pooling of the river. But the core 22 conducts heat from the block at the end thereof away. Furthermore, in the absence of special precautions, the core would suffer damage, namely by the Heating and cooling. Therefore the cushion 35 is used to pool the river with it to be able to make a core, but still eliminate the high heat losses due to the core 22.

Assuming that the device is operating in the upright position shown, at Operation of the block is placed on the insulating cushion 34, which is on the head of the piston 33 lies, and the piston 32 is then driven to move the block to the predetermined position move up. The clamping bar 21 is then loosened and the core carrier 20 in its holder 14 lowered until the lower surface of the insulating pad 35 rests on the upper end of the block or a small distance above it. The clamping bar 21 is then tightened to the holder 14 and to clamp the core carrier 20 in a fixed position to one another. One end of the coil will then connected to a power source. Depending on the length of the block and its pre-selected position the other pole of the energy source is connected to a correspondingly selected tap 2. This is usually chosen so that the effective length of the coil is 7Va to 10 cm above the upper end of the block extends towards the upper end 9 of the spool. Through the supply line 30 ° gas is introduced, cooling water or other liquid is passed through tube 26, and then the coil is energized.

If the block tries to change its position axially due to the magnetic propulsion, the piston 33 and the carrier 20 can be adjusted in the holder 14, so that the block accordingly can easily be held in the precise, predetermined axial position in the spool can.

After the block is heated and removed, a new block is placed on the insulating one Cushion 34 placed on the head of the piston 33. Of the

The piston is then pushed up into position and current is applied to the coil. Any force that from the block driven axially to the coil by the magnetic flux and which causes that the block abuts violently against the core, is by the springs 19 over the carrier 20 and the Holder 14 intercepted, and the block is returned to its original, previously determined heating position. Should a longer block be introduced without changing the position of the core, then in in the same way the impact of this longer block against the core is intercepted.

Successive blocks of the same length can be heated without further adjustment.

If an even flow rate is desired over the entire length of the block, the number of turns of the group, which is at the end of use 8, is greater than the number of turns each of the groups moving from the insert end 8 towards the opposite end 9 lie down. Preferably, the width of each turn of the group that is closest to the end is eight is about half the width of each turn of the group that is closest to the end 9.

The density of force lines at the end of use 8 would otherwise only be half as great as a result of shunt paths be like at the transverse median plane of the coil.

The water-cooled layers at the end 9 concentrate the flux of a considerable part of the coil, the is above the top of the block, and thereby the magnetic field strength is at the top Increased at the end of the block to compensate for losses that would otherwise occur. Through this the magnetic field strength at the upper end is approximately equal to that at the transverse center plane the coil. At the same time, the cushions 34 and 35 reduce heat losses. With such a Arrangement can produce a much more uniform flow and thermal image over the whole Length of the block can be obtained.

As can be seen, special heating effects can be achieved in which the temperatures of the block different locations along the block to meet special requirements.

The device according to the invention has the advantage that it can be purchased at low cost, operate and maintain and has a small footprint that they can continue to operate independently Appropriate working method and a very adaptable temperature control enables that lead to an improvement of the product leads. Finally, there are improved working conditions for the operator and easier scheduling of production.

Claims (8)

Patent claims: 1. Low-frequency induction heater, in which the metallic insert to be heated is inserted into the axial channel of the induction heating coil can be introduced through one end of the channel and in which a core serving to concentrate the magnetic flux in the channel inside the heating coil can be introduced, characterized in that a portion of the coil (1) is provided with several customer taps (2) distributed over its length and that the Core (22) for bundling the magnetic flux in different positions along this section is adjustable. 2. Low frequency induction heater according to claim 1, characterized in that a heat insulating Body (35) is inserted between the core (22) serving to bundle the magnetic flux and the insert to be heated. 3. Low frequency induction heater according to claim 1, characterized in that a heat insulating Body (34) inserted between the end of the insert facing away from the core (22) and a carrier (32, 33) of this insert is. 4. Low frequency induction heater according to claim 1, characterized in that for deriving the heat from the core (22) concentrating the power flow, coolant (25) are provided. 5. Low frequency induction heater according to claim 1, characterized in that the heating coil (1) is arranged with its axis in an upright position and at least part of the den Power flux bundling core (22) sits on the upper portion of the coil in the inner channel, while the carrier of the insert to be heated is arranged in the lower end of the coil. 6. Low frequency induction heater according to claim 1, characterized in that the coil fewer turns per unit length on the portion of the coil where the consumer taps (2) are provided or along this portion of the coil. 7. Low frequency induction heater according to claim 1, characterized in that the the Power flux bundling core is attached to a core support (20) at one end of the Coil arranged and is movable back and forth in the longitudinal direction, the core in the Coil extends into it when the core carrier is in the position that the coil on next lies. 8. Low-frequency induction heater according to claim 1, characterized in that resilient Means (19) are provided, which the core carrier in the longitudinal direction of the coil on this to seek to move. Considered publications:
German Patent Nos. 835 032, 540 519, 710, 855 607, 869 385, 881 521, 881 558, 910 463; German patent application S 26647 VIII d / 21 h (published on September 16, 1954); U.S. Patent Nos. 2,452,197, 2,457,846. 1 sheet of drawings ! © 909 725/452 1.60