US236235A - Hugh mcdonald - Google Patents

Description

(NoModel.)

' H. MGDONALD. Furnace Shield. No.. 236,235. Patented Jan. 4,1881.

ILPETERS, PNOTQUTHOGRA'HER. wAsHxNGToN. :J c.

l lUNrrn HUGH MGDONALD, OF ALLEGHENY, PENNSYLVANIA.

FU RN'ACE-SHIELD.

SPECIFICATION forming part of Letterslatent No. 236,235, dated January 4, 1881.

Application filed April 2, 1880.

To all whom t may concern Beit known that I, HUGH MCDONALD, of Allegheny, county of Allegheny, State of Pennsylvania, have invented or discovered a new and useful Improvement in Furnace- Shields 5 and I do hereby declare the following to be a full, clear, concise, and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, in which--like letters indicating like parts- Figure l is a side elevation, slightly in perspective, of a puddling or boiling furnace with my improved shield applied thereto; and Fig. 2 is a sectional view through the shield and the door ofthe puddling-furnace, showing the position of the shield when in use relative to the furnace.

The excessive heat required in the puddlin g or boiling or reheating or other treatment of iron or steel is such as to be exceedingly oppressive to the workmen, and to interfere materially with the best exercise of skill in doing the work. As a device for guarding against the edects of such high temperature, and toenable the workman to bring out a maximum amount of work in the best condition with the least exposure to himself, shields have been arranged in front of the furnace-door.

My present invention relates to the construction of a shield for such use, and while I have shown it as applied to apuddling orboiling furnace I do not limit myself to the combination of it with any partieularkind or class of furnace, butinclude herein the construction described in its application to any kind or class of furnace where protection to the workman is desired as against excessive heat.

A puddling-furnace of ordinary construction is shown at B. The vertically-movable door D, through which to charge the furnace and remove the product, is of the usual or any known construction. It is provided with the usual stopper or work-ing hole d. Since the workman has to stand opposite-the door in charging, workin g the charge, making up, and removing the ball, protection is chiefly needed at this point. To this end I suspend a movable shield, A, opposite the door, but at a little distance therefrom, as shown in Fig. 2, chiefly in order that the air may circulate (No model.)

freely in the intermediate space, and lessen to that extent the conduetionof heat from the furnace to the shield. This shield is composed of a plate of metal, a, extendingover the whole or the greater part ofthe back of the shield, Q

` properties of such materials as non-conductors are so well known in other branches of the art that the skilled workman will have no difficulty in proportioning the thickness according to the amount or degree of protection desired. For ordinary purposes I consider a thickness of about three or four inches sufficient.

This shield is, by preference, made large enough to cover so much of the side of the furnace as comes within the range of the usual positions of the Workman in doing his work, and is made with a recess in its lower edge of suitable size and position for uncovering the stopperhole, as shown, and the ange a2 around this recess gives room for the proper manipulation of the workmans tools. It may be made movable in any suitable way, as by being hinged at one edge, or raised andlowered by a lever, or, as the preferable Way, it may be hung by straps c and friction-rollers c on a track-rail, b, which is supported from the furnace-frame by brackets b', so as to be run to one side and out of the way to a position indicated by dotted lines whenever necessary for charging or xin g the furnace, or for removing the ball, the workman for this purpose manipulating the shield by the handles at a4.

The structure of shield described may be modied somewhat without any substantial departure from the scope of the present invention, as, for example, an outside plate may be added, as shown by dotted lines at c, Fig. 2, so as to give a hollow box, in which case the non-conducting material may be run in a plastic state or filled in dry, as may be preferred; or, as another modification, a like layer of non- IOO conducting plastic material may be placed ou the back of the plate a, asillustrated by dotted lines e of Fig. 2; but in this case the shield should be hung a little farther from the furnace than is represented, in order that the proper air-space may be provided between the two, and here, as before, any suitable plastic having a low heat-conducting power may be employed.

The principal object I have in View in the making of a shield in the manner herein described is to utilize for the purpose such materials as can be best employed in a pulverized, broken, or oomminuted state; and While the best results may be secured by the use ot' material having.,r the lowest heat-conducting power, other thin gs being equal,it is stilltrue thaty advantageous results may follow from the use of materials which are much better conductors of heat than those which I have specifically named. Hence, by the term like material, as herein used, I mean a material pulverized, ground, broken, or comminuted; and as to its heat-conducting power, itis only essential that it be solow as to be adapted to operate asa barrier or shield under the circumstances named.

I claim herein as my invention* A furnace-shield consisting ofY ametal plate lined on one or both sides with plaster-of-paris, lime, or other like material having a low power as a conductor of heat, movably arranged at the side of a furnace opposite the door, anda littl 3 distance therefrom, substantially as and for the purposes set forth.

In testimony whereof I have hereunto set my hand.

HUGH MCDONALD.

Witnesses:

R. H. WHITTLESEY, G. L. PARKER.

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