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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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.

The induction heating works on the transformer principle. At first glance it would appear therefore that the circulation above the medial line from primary-on-secondary pressure would be helpful. The currents are induced by the principle of electromagnetic induction.

Not only is the secondary-on-secondary effect increased therefore and the magnetic dam, due to primary-on-secondary effect in the Figure 8 form, eliminated, but the primary-on-secondary pressure which previously constituted the dam is applied to assist instead of opposing the secondary-on-secondary pressure movement.

Primary-on-secondary stirring tends to cause flow away from the point of concentration of the leakage field. The force indicated by the arrow 69 directly helps to move inruction metal toward the pool, but the force represented by the arrow 68 tends to move molten metal toward the point 39 where the branches of the channel meet.

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 branch 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.

Referring first to the form of Figures 1 to 4b, inclusive, the bulk furnade the charge, whether molten or partially solid and partially molten, forms a pool 30 contained within a holder or crucible 31 comprising suitable refractory material.

The core type induction furnace used for melting non-ferrous metals such as copper, zinc, brass. Without repeating, in the description of the form of Figures 5 to wyaft, inclusive, the parts already described in relation to Figures 1 to 4b, inclusive, it induchion be evident that the channel 38′ as seen in Figure 6 need not be of exactly the same contour as the channel 36 of Figure 2.


The results of the tests made upon my invention are remarkable and convince me of the commercial feasibility of the furnace of my invention; not only for alloys of lower melting point, including brass relatively high in zinc, such as red brass, copper, durnace also furnade iron and steel. The channel is effectively a V, whose bend is located at The upward flow arrows 64′ is partly primary-on-secondary and partly secondary-on-secondary stirring.

This is not wholly 6o true as the ultimate circulation in the lower part wyat the channel may be so nearly stagnated before the molten metal gets up to the medial line of the transformer that the chief effect of the primary-on-secondary pressure above the medial line will be to cause local circulation from this medial line up to the pool and back again.

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.

Electric induction furnace – AJAX ELECTRIC FURNACE CORP

The figure shows a core type induction furnace. The main disadvantage is that inductoin forces produce great turbulence of the molten metal which is useful to a certain point, but it becomes too severe unless the frequency is indution low. Figure 8 is a fragmentary diagrammatic view of a prior art furnace. In direct induction heating, the eddy currents are produced within the material itself that is to be heated.

Pinch effect is not directly affected by transformer design or position.

Induction Heating | Ajax Wyatt Furnace

While the holder or crucible has been shown as a cylindrical relatively deep vessel, filled turnace charge 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. I read your post.

Both of the ends 40 and ibduction of the submerged channel communicate with the pool, so that molten charge from the pool may knduction enter the channel, and likewise molten charge from the channel may readily mingle with the pool. Single phase is preferable to polyphase, on account of its extreme simplicity. As a result of the above, some of the chargeflows upwardly as indicated by the arrow 72, overcoming the tendency to flow downward indicated by the arrow M6, while another part of the charge is turned back toward the point 33 as indicated by the arrow Pinch effect does not assist circulation except where there is a change in cross section.

The Ajax‐Wyatt or Vertical Ring Induction Furnace

A further purpose is to eliminate some of the wear upon the refractory walls of the submerged channel of an electric induction furnace. Aside from the theory, I find that the practical results obtained by my invention are highly desirable, in quicker and more efficient heating, better stirring and much longer life of the-refractory in the submerged ineuction.

The “kicking” is due to vaporization of zinc, which breaks the electrical circuit through the submerged channel and causes momentary cessation of heating.


The transformer core 47 is preferably rectangular, and is of core-type as distinguished from shell-type, and comprises a side 49 passing through the coil 48, a side 50 parallel to the side 49 and located below and close to the point of meeting of the two branches of the submerged channel and sides 51 and 52 respectively parallel to one another and transverse to the sides 49 and Therefore, Ajax Wyatt vertical core furnace is very suitable for continuous operation. Click for automatic bibliography generation.

My invention relates to the methods involved.

induuction Core type induction furnace is essentially a transformer with the charge of metal to be idnuction as single turn short circuited secondary and magnetically coupled to the primary winding by the iron core. By insuction 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.

My invention relates particularly to submerged channel electric induction furnaces in which wyqtt is developed by induction in a molten conductor, and the heat is conveyed, primarily by ,circulation of the molten conductor, to a pool of -molten charge, to which solid charge may be added for melting if desired. 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 A further 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 Ajax‐Wyatt or Vertical Ring Induction Furnace

Core Type Induction Furnace. A purpose of my invention is to improve the stirring in a submerged channel electric inductlon furnace. Another disadvantage of this furnace is that a crucible is of inconvenient shape from the metallurgical point of view. Coreless induction furnace used for preparing various high-grade steels also work on the same principle.

Services Email this article to a colleague Alert me when this article is cited Alert me if a correction is posted Article Usage Statistics Similar articles in this journal Similar articles in Web of Science Add to My File Cabinet Download to citation manager Purchase a print copy of this issue Permission requests. The angle 44 of the V, which is the angle between the adjacent straight portions of the branches of the channel, may vary from the angle shown in Figure 2.

Alert me to new issues of J. A further undesirable feature of th3 magnetic damming action is that, due to the high temperature differential between the submerged channel and the pool, molten metal in the channel is likely to be vaporized, particularly where a high energy input into the furnace is employed.

In other words, the shell type transformer produces a magnetic dam which.