US1951766A - Method and apparatus for treating sheets - Google Patents

Description

March 20, 1934. I N, B. oRNlTz 1,951,756

METHOD AND APPARATUSQFQR TREATING SHEETS Filed May 19, 1950 INVENTOR 4Piitented Mar. 2o, 1934 l 1.951.766 i METHOD AND Arranilig'rns ro Tammo SHE Nathaniel B. omitz,

Pittsburgh, ra., assit-nor tu National Alloy Steel Company, Blawnox, Pa., a

corporation of Pennsyl Vania Application May 19, 1930, sei-iai No. 53,482 1 c. (ci. 2st-c) My inventionr relates to theheat-treating or annealing of sheetsand, in particular, .contemplates a novel method and apparatus for convey- .ing the sheets through an annealing furnace.

It has been -found that the steel rolls forming the conveyors now used for passing sheets through an annealing furnace tend to collect coats of oxide which are rough and pointed so that sheets passing thereover become scratched and dented. Such sheets, of course, are not perfect and must be 'scrapped or given an inferior grade by the inspector. In some instances, it has been the practice to place a perfect sheet on top of an imperfect sheet. lresting on the conveyor rolls. 'I'he top sheet'is thus protected to some extent from abrasion by the rolls,` although, in many instances, the upper sheet is dented through the lower one by the projections from the conveyor rolls. l

When the rolls reach this stage of oxide coating, it is necessary to shut down the furnace until the rolls can be polished by grinders. This shutting-down is along process and is a serious curtailment to the production of the furnace. A period of several days is necessary for cooling the furnace and further time is required forthe actual polishing of the rolls before the furnace can again be placed in service. i l

I have invented a method and means for passing sheets through an annealing furnace which avoids the objections above-mentioned. According to the invention, I employ a conveyor having supportingelements formed of refractory or nonoxidizable material such as silicon carbide'. Such surfaces do not tend to form any oxide coat which would mar the iinish of the sheets passing through the furnace. In addition, the problem of localized chilling, which has been met with heretofore, is lsolved by this construction.

For a complete understanding of the invention, reference is made to the accompanying -drawing in which, v j y Figure 1 is a partialside elevation of a conveyor constituting a present preferred embodiment of the invention;l f

Figure 2 is an end elevation;

Figure 3 is a top plan view of the portion of the apparatus shown in Figure 1; and

Figure 4 is a partial side elevation of a furnace havingy a modied form of conveyor therein.

' Referring in detail to the drawing, I provideA a conveyor composed of a plurality of carriers such as that sho'w'n at 10. The carrier 10 comprises a central vertical web portion 11, a bottom link portionlZ, and a top supporting portion 13. 12 of the carrier is connected, for instance, by links 14.. and 15, tosimilar that shown at 10. A number of Vsuch 4carriers linked together form a coninuous conveyor passing through the annealing urnace, the oor of which is indicated schermati cally at 16. The conveyor may be driven by any convenient source of power. The web portions 11 of the carriers 10 ride in a slot 17 in the door of the furnace and the links 14 and 15 and the bottom portions of the carriers pass through a channel 18 connecting with the slot.

The top portion of thecarrier is provided with fourprojecting arms 19, 20, 21, and 22. At their outer ends, these arms support pads 23 "having dovetailed slots 24 therein. .Refractory inserts 25, which may be ofv any suitable material such as silicon carbide, have dovetailed projections 26 fitting into the slots 24. The inserts 25 afford a series of spaced'refractory supports for sheets being conveyed through the furnace. Any suitable non-,oxidizing material may be used. for the supporting inserts 25.

In operation, the conveyor is driven continuously and the vsheets are placed individually on the carriers and so pass through the furnace. No oxide coat forms on the refractory inserts 25 to scratch or dent the surface of the sheets. Since there is no relative movement between the supporting surfaceand the sheet in this type of conveyor, the latter is without a marl:` or blemish when taken from the delivery end of the furnace. Because of the thermal qualities of the insert, no localized chilling occurs and the nished sheet is uniformly treated throughout its area. Y

` A modified form of the invention is illustrated in Figure 4. According to this modification, a roller conveyor is constituted by a plurality of rolls 30.' The rolls 30 are provided with refracinserts 31 similar to those shown at 25 in the first form of the invention. 'I'he inserts 31, of course, are curved tor conform to the surface of the roll 30 The advantages resulting from the preferred form of the invention are also inherent in the modiiied form shown in Figure 4.

Although I have illustrated and described but two embodiments of the invention, the scope thereof is notllimted to the specific details of these modifications. Any changes may be made in the construction Without departing from the spirit of the invention as set forth in the apl sheets.

- NATHANIEL B. ORNITZ.

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