In this article we will discuss about the design of core and coreless induction furnace. An improved form of core type furnace is Ajax-Wyatt vertical core type . ea1 ring induction type. CONSTRUCTION. OF FURNACE. The vertical-ring ioduction furnace makes use of the pat- sented Ajax-Wyatt heating element. VERTICAL CORE TYPE INDUCTION FURNACE Also known as AJAX-WYATT FURNACE. Vertical crucible is used for the charge. Bottom is usually V-shaped or .

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Therefore, Ajax Wyatt vertical core furnace is very suitable for continuous operation. My invention relates to submerged channel electric induction furnaces. In the drawings, two main types of submerged channel electric induction furnaces are shown. It will be evident that both of the moving forces used primary-on-secondary and secondary-on-secondary are motor effects.

Figure 2 is a central vertical section of Figure 1, taken on the line The charge is given from above and the molten metal is taken out through the spout. In both forms, likewise the coil surrounds the core and is located between the branches.

Related Content Load related web page information. By explaining the theory upon which my invention is believed to operate, I do not wish to limit myself to this theory nor to make the correctness of the theory essential to the protection afforded my invention. In the prior art, the general practice has been to construct a submerged channel electric induction furnace as illustrated in Figure 8, with the coil between the branches of the channel surrounding the middle leg of a shell-type transformer core, whose outer legs are each outside the channel.

The coil 48 is protected from the molten charge by the refractory walls of the channel, and may be cooled if desired by any suitable means, such as a blast of air.

The same general variations may be made in the construction of Figures 5 to 7b as incuction that of Figures 1 to 4b. In an electric induction furnace, a crucible adapted to hold a charge, walls forming a submerged channel depending from the crucible, communicating at its upper ends with the crucible and having a V-bend whose angle point is directed away from the crucible, a closed rectangular transformer core surrounding the Vbend, having a first side extending transversely of the plane of the channel above the V-bend, a second side parallel to the first below the Vbend, and third and fourth sides joining the ends of the first two sides, there being but one channel conduit within the transformer core, and insuction energized means including a coil surrounding said first side and comprising the sole energization of the core to set up lines of magnetic force in the magnetic circuit having a maximum at the angle.


The examples of direct induction heating are the high-frequency eddy current heating used for case hardening or tempering of various machine parts, annealing of steel strip and soldering. It is also knduction as eddy current heating. Moreover, in the indirect induction heating method the eddy current are induced in the heating elements by electromagnetic induction which produces heat in heating elements.

The Ajax‐Wyatt or Vertical Ring Induction Furnace

From another standpoint also pinch effect dis-cussion herein can be eliminated because pinch effect is a function of “tube” or channel design and the tube can be designed to take care of the pinch effect. The present invention applies to submerged channel furnaces having angles in the channels whose syatt are directed away inductin the pool, whatever the cross sectional contour of the submerged channel and the contour is therefore not specifically claimed in this application.

The edgepresented contour 59 of Figure 4a might also be used and somewhat less desirably the flat-presented contour 60 of Figure 4b could be employed.

If the channel lacked the angle 44 and were circular as viewed in the plane of the length of the channel that is, in the plane of the paper in views such as Figures 2, 2a, 6 or 8the repulsion forces would be nearly balanced, completely balanced if there were a complete circle of uniform cross section and secondary-on-secondary repulsion stirring could be ignored. A proper arrangement is made for fitting the furnace to take out molten metal.

The currents are induced by the principle of electromagnetic induction.

Induction Heating | Ajax Wyatt Furnace – your electrical guide

A further purpose wyatg to start primary-on-secondary stirring in the submerged channel of an electric induction furnace at the same point at which secondary-on-secondary stirring is initiated. A ywatt purpose is to concentrate flux at the bend of a submerged channel angle having the point of the angle directed away from an electric induction furnace pool.

The charge is heated by a submerged channel 36 having branches 37 and 38 meeting at 39 in an angle whose point is directed away from the pool At first glance it would appear therefore that the circulation above the medial line from primary-on-secondary pressure would be helpful. Figure 3 is a fragmentary section of Figure 2 on the line Pinch effect flow, due to the tendency of current in different parts of the same molten conductor to constrict the conductor and to cause ‘5 molten metal to flow upwardly along the middle of the channel has been considered in the above discussion, but has not been discussed before nor further than is herein explained for the reason that the elimination of counter-pressures along the outer walls of the channel, provided by my invention herein, inducttion highly beneficial whether pinch effect be weak or strong.

Due to the secondary-on-secondary stirring, there is a tendency to cause molten metal to flow upwardly from the point 39 along the outside of the channel in each branch toward the pool as indicated by the arrows 64, and to permit molten metal to flow by gravity down the inside of the channel from the pool as indicated by the arrows 66, to replace the upwardly flowing molten metal.


AJAX furnace

As a general rule all bobbins are having through-opening terminals, yet just picked littler center. My electric induction furnaces are- ordinarily used to melt metals and alloys and.

This causes secondary-on-secondary flow along the inner 3o channel walls at the angle directly opposing gravity return flow from the primary-on-secondary circulation.

The melt is completed in about 1 to 2 hours for large sizes and in lesser time for smaller sizes. The transformer core 47 will of course be made of laminated sheets of transformer iron, which are assembled by overlapping individual sheets at points of joining as in conventional transformer practice. To overcome this difficulty, core type induction furnace is operated at a very low frequency say 10 Hz. This furnace is very suitable for continuous operation and it can be operated on normal supply frequency i.

Its efficiency is about 75 percent. In any event, the primary-on-secondary pressure above the medial line can be of little benefit in assisting circulation within the channel below the medial line. In an electric induction furnace, a crucible adapted to hold a molten metal charge, walls forming a single-conduit submerged channel depending from the crucible, having two branches, each communicating with the crucible at its upper end, converging one with respect to the other branch along a straight portion and meeting the other indkction at its lower end in an angle whose point is directed downwardly and a transformer core passing around and linking the angle, having its sole exciting coil between the channels and part of said core outside of but close to the angle for concentrating flux at the angle in excess of that in the channel branches close to the crucible, there being but one channel per transformer.

Figure 7a is a view similar to Figure 7, showing a different channel cross section. While the holder or crucible has been shown as furnacce cylindrical relatively deep vessel, filled with indjction to a suitable depth, as for example, up to a level 35, it will be understood that any proper shape of crucible may be used, as best suited to the particular case, and the depth and contour of the crucible may be adjusted accordingly.