No. 853,669. I PATENTED MAY 14, 1907.
' G. E. WISENER.
PIT FURNACE covm AND METHOD OF MAKING SAME.
APPLIGATIONI'ILED DEO.1.1906.
M W5 7W8 I WITNESSES IHE NORRIS PETERS ca, WASHINGYON, n. c.
GEORGE E. WISENE R, OF MUNHALL, PENNSYLVANIA.
PIT-FURNACE COVER AND METHOD OF MAKING SAIVIE.
Specification of Letters Patent.
Patented May 14, 1907.
Application filed December 1, 1906. Serial No. 345.921.
To all whom it may concern:
Be it known that I, GEORGE E. WISENER, of Munhall, Allegheny county, and State of Pennsylvania, have invented a new and useful Improvement in Pit-Furnace Covers and Method of Making Same, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1. is a top plan view of a pit-furnace cover, constructed in accordance with my invention and Fig. 2 is a sectional side eleva tion on the line IIII of Fig. 1.
My invention relates to the removable covers employed with pit and other vertical furnaces, in which the opening or mouth of the furnace through which materials are placed within the furnace, is located in its top and the object of my invention is to provide an improved cover by the use of which the necessity for frequent repairs to and renewals of such covers are avoided and the cost of maintaining such covers is reduced.
A further object of my invention is to provide improved means for drying such covers, by the use of which, cracking and distortion of the covers in their frames is lessened and largely prevented and in the use of which the time required f'orsuch drying operation is greatly reduced.
The covers for such pit furnaces are alternately heated and cooled by the frequent shifting of the covers in covering and uncovering the mouths of the furnaces, and, when the covers are over the furnaces, the inner surfaces of the covers are subjected to a very intense heat.
Heretofore in constructing such covers, it has been the practice to form a lining of refractory bricks which was built into an arch extending between the sides or ends of a metallic framework forming part of the cover. After such covers have been in use for a short time, these linings become loosened in the framework, particularly in the corners. The linings also frequently crack, both in drying and after being put into use.
By the use of my invention these difficulties are largely overcome, the life of the covers is greatly increased and the cost of forming the covers is reduced.
In the drawings, 2 represents the body formed of suitable refractory material, in the
frame 3 of a pit furnace cover. The cover is provided with the usual vertically-
adjustable bearings 4 in which the
axles 5 for the
track wheels 6 are mounted, and a suitable opening 9 is provided in the cover through which the interior of the furnace may be observed without moving the cover from its position over the mouth of the furnace.
In forming pit covers in accordance with my invention I provide a former or mold. (not shown) having the desired curvature for the inner surface of the cover. This former is placed in position within the
frame 3 of the cover and a quantity of plastic refractory material is then spread. in a layer over the top of the mold so as to form the inner surface of the
body portion 2 of the cover. As the material is being spread and rammed in place a series of
perforated bricks 7 are spaced at intervals within the
frame 3.
' The
perforated bricks 7 are held in position by the firstlayer of plastic material while the additional material is being spread and rammed in place in the frame to form the full thickness of the body. After the desired thickness for the body has'been formed, the cover is dried, and, in order to hasten the drying operation, heat may be applied, if desired. The heat rising through the
perforations 8 in the
bricks 7 radiates through the cover and tends to dry it more quickly than is possible when the cover is dried inwardly from its outer surfaces. The
perforations 8 in the
bricks 7 also prevent the cover from cracking and becoming loose in the
frame 3 while being dried. After the cover is dried the
perforations 8 in the
bricks 7 are filled with slurry or a thin solution of refractory material until they become entirely closed. This operation may be performed after the covers are in place on the furnace if desired.
Modifications in the construction and method of forming-the covers may be made within the scope of my invention. The plastic material may be rammed to the full thickness of the body of the cover in one operation, instead. of in layers as described.
Instead of using perforated bricks in the covers, it may be formed wholly of plastic material. In such case the holes may be formed through the cover while. it is plastic, being closed after the cover is dried and other variations may be made.
The method may also be used for furnace doors or other refractory articles similar to pit furnace covers.
I claim 1. The method of forming pit furnace covers or similar articles which consists in ramming plastic, refractory material Within a suitable frame, providing a multiplicity of small drying passages through the plastic i material and drying the material.
2. The method of forming pit furnace covers or similar articles which consists in ramming plastic, refractory material Within a suitable frame, providing a multiplicity of small drying passages through the plastic material, drying the material and finally closing the drying passages.
3. The method of forming pit furnace covers or similar articles, Which consists in i placing bricks having perforations therethrough Within a suitable frame, ramming plastic refractory materials around said bricks Within the frame, drying the materials, and finally filling the perforations in said bricks.
4. A pit furnace cover or similar article comprising a frame, a refractory body molded in place within said frame, and a plurality of drying passages extending through said refractory body.
5. A pit furnace cover or similar article comprising a frame and a refractory body molded in place Within said frame, holes through said lining and a iillingin said holes.
In testimony whereof, I have hereunto set my h and GEORGE E. \YlSlCNlGR.
\Vitnesses Josnru Gliovnn, U. L. Wilson.