PHYSICAL TESTS FOR THE BLAST FURNACE, ETC. 499
increase in sulphur caused by remelting in the small cupola cannot be regarded as any greater than would result from remelting in large cupolas. If anything, it is a little below what might be expected with fair usage. This is due to the iron not remaining in the baby cupola as long as in ordinary foundry cupolas.
I will now proceed to describe a system of testing which I installed 'at the Spearman furnace at Sharps-ville, Pa., January 17, 1896, in which the managers took great interest and used, without a doubt, with much pront to themselves.
The outfit includes one Olsen transverse testing Hx«t-chine of standard make, one cupola, two flasks, and chill pig--moulds with a test bar pattern and mould-board. An excellent feature of the whole equipment is that it need not cost over one hundred dollars, including- the testing machine. The price of such an outfit is no more than a furnace might have to pay for freight on one or two cars of condemned iron.
The cupola. Fig. in shows the cupola used. It may have a C£ drop bottom," as shown, or it may simply rest upon a plain plate, and be tipped by hand to clear it out, after the conclusion of heats. The figure itseh explains all details necessary to the construction and plan of charging the cupola, as seen on next page.
The cold blast is used so as to be the same as in foundry practice. It may require a few trials to find out what pressure of blast will give the best results. It should not exceed eight ounces pressure at the cupola, and will generally be found to work best at about six ounces, where two one-inch tuyeres are used. Where a low pressure of about four ounces can -be
*lf one is inexperienced in managing cupolas, I would advise the cupola being 14 inches inside diameter instead of 10 inches, as shown, and increasing the tuyere area 30 percent.; that is, if a novice desires to use the smallest cupola practical for melting small samples. "............ " " i in square hnrH........................