This stove is built by Arthur G. McKee & Co., contracting engineers, Cleveland, Ohio. The principal claims for the stove are that it secures a very large area of heating surface in proportion to the total cross section of the stove, and that there is in it a very small percentage of any brick except standard shapes, regularly kept in stock by brick manufacturers.

Fig. 141. Horizontal sections of M'Kee Nelson stove.

This stove is clearly shown by Figs. 139, 140, and 141. It will be noticed that the back or inside wall of the combustion chamber is given a radius or a curvature the same as that of the front wall. This is a matter of much importance because when this wall has too flat a curvature it becomes a very weak arch and does not resist the thrust due to the expansion of the checker work, and in the past, before experience had taught this costly lesson, many stoves were put out of commission and required to be relined long before they would have been had this point been properly guarded.

The checkers are square in shape and well bonded, and the walls between the flues on which the checkers are built are substantial, so that while these stoves have only been in use for some four or five years, they are well regarded and have given good service.

Roberts Two-Pass Side Combustion Chamber Stove

In order to meet the views of those who desired a stove of this type Frank C. Roberts & Co. also furnish one of the design shown by Figs. 142 and 143.

This stove uses exactly the same checkers as the Roberts three-pass stove. It is so completely shown by the drawings that no fuller description is necessary.

Fig. 142. Roberts two-pass side-combustion stove - vertical section.

The Two-Pass Central-Combustion Chamber Stove

Some operators, while admitting the disadvanatge of the three-pass construction and preferring the two-pass type, consider the central combustion chamber the best, and a type of stove designed by Frank C. Roberta & Co. to meet this demand is shown by Figs. 144 and 145.

The type of checker work used in these stoves is of the same type as that used in the three-pass stove, except that, instead of being designed for square checkers, it is designed for radial bricks on two sides and circumferential ones on the other sides. This checker work is shown in perspective view by Fig. 145. The construction of the stove is obvious from the drawings and from what has been said of the principles on which it is based. It is provided with the ordinary accessories in the way of cleaning doors, etc.

Mr. Julian Kennedy was one of the first designers of two-pass central combustion chamber stoves and used, instead of brick checkers, hollow tiles, with openings through the center about 9 in. square. The sides of these were radial and the fronts and backs circumferential, so that when stacked up in the stove they made a series of radial checkers whose circumferential width gradually increased from the combustion chamber back to the lining of the stove.

The objection to this construction was that a special shape of hollow tile was needed for each ring of checkers and that the partition wall between each two checker openings being made up by the adjacent sides of two of these hollow tiles was split vertically, therefore its strength was not great, and if one of these gave way it was likely to turn over and obstruct the checker completely. If this happened anywhere in the checker except right at the top it was practically impossible to fix it, and that checker was lost to the stove for the balance of the life of its lining, so stoves now generally have checkers of brickwork built up in the ordinary way.