AUGUST 10, 1894. Vol. IV. No. 24. BOCKA Dublished Monthly by THE FOUNDRY • PUBLISHING@ DETROIT. MICA W.M.Smith,Librarian, Madison, Wis. Dear Sir: Replying to your favor of recent date would say, we do not publish a Title Page Index to THE FOUNDRY. We have never as yet had sufficient call for them. Will try to send you numbers 49 and 50,as per your request. Yours truly, THE FOUNDRY PUBLISHING CO. Dictated J.A.P. methion 0.6. cannot be furnished to mot No.49 0. No 50 reed. Editor & Manager. 9-10VOL 8.. Cupola Practice. H. M. RAMP. PART II. DETROIT, MICH., OCT., 1896. The center of the cupola requires very little blast, theoretically none; but the instant you move from the center on the radius the amount of blast required is constantly increased, for the area represents the blast necessity. The nearer the side of the cupola is approached, the greater demand it makes upon the blast volume, for if our blast was sufficiently concentrated and of such power as to force its major portion to the center the outside area would be robbed and cooled and cause greater disaster. For example, assume that in a 48-inch cupola the blast does not penetrate within six inches of the center, which would leave a circle of twelve inches in diameter in that point unsupplied with blast, a melting area of 113 square inches. Or, again, assume you reach the center, and the force and volume of the blast are so great you cooled the cinders and droppings around the outside diameter one inch thick, or forced the blast in so one inch would be neglected. The result would be that one inch on the outside diameter would cut off 150 square inches of melting area, considerably more than a twelve-inch circle in the center. Yet how often the cupola bottom is dropped and one, two, three, yes. and even six inches of accumulations will be found hanging to the side above the tuyers, cutting off hundreds of inches of melting area. Most certainly there is a reason for both of these conditions, and it is often the direct result of the dimensions of tuyers used. If the cupola accumulates around the edge, the tuyers are too large; too great a body of air is entering at one point, which cools anything that may be in its path before it becomes sufficiently heated. Too high blast pressure will also cause the same result. Many cupolas are driven beyond their capacity the first hour and melt rapidly, but No. 50 gradually bring up and melt slower until at the end of the second hour their usefulness is at a practical end for that heat. The outside diameter of melting area is the portion that should meet our attention and consideration first; the center later. The cupola that works well all through a heat of two, three or four hours and drops clean and clear will be found a rapid and economical one to use, and the blast and tuyers will most certainly represent correct proportions. Center blast attachments are of comparatively recent origin, and their application is successful and economical, but the name "center blast" conveys the wrong impression. Practically our old style cupolas are center blast, for that is the point to which they endeavor to force the blast, while the so-called center blast of to-day is situated in the center and forces the blast to the outside diameter, the very point where it is needed most, and it is only plausible to suppose a cupola operated with one of these must constitute a great saving in time, wear of lining, to say nothing of possible economy in fuel, and, futhermore, is an exemplification of the idea just advanced that the outside melting area is of more importance than the center. Distribution of the tuyers or blast volume varies. Some cupolas have only four to six tuyers, while others will possess forty. One of the best working cupolas the writer ever saw had thirty-six two and one-half inch round tuyers, and the iron melted hot at a low ratio of fuel and great rapidity. But the practice of placing four or six large tuyers in a cupola of forty-eight inches diameter is undoubtedly an error, for the points between the tuyers do not receive their full quota of blast, and the points in front of the same are chilled and cooled by the excessive volume. Running a cupola correctly is based on common sense rules, and the reason so many mysterious, unexplainable things occur is simply because we have not sufficiently exercised our thinking faculties. Eliminate everything that is not rea |