Info

along with the usual (but not universal) dimensions of the cylindrical copper capsules. The same numbers arc now applied to commercial blasting caps of the same sizes, whatever the weights and characters of the charges. A No. 6 cap, for example, is a cap of the same size as one which contains 1 gram of straight fulminate. No. 6 caps of different manufacturers may differ in their power

Figure 96. Manufacture of Detonators. (Courtesy Hercules Powder Company.) The safe mixing of the primary explosive charge for blasting caps is accomplished mechanically behind a concrete barricade by lifting slowly and then lowering first one corner of the triangular rubber ¿ray, then the next corner, then the next, and so on. In tlie background, the rubber bowl or box in which the mixed explosive is carried to the building where it is loaded into caps.

Figure 96. Manufacture of Detonators. (Courtesy Hercules Powder Company.) The safe mixing of the primary explosive charge for blasting caps is accomplished mechanically behind a concrete barricade by lifting slowly and then lowering first one corner of the triangular rubber ¿ray, then the next corner, then the next, and so on. In tlie background, the rubber bowl or box in which the mixed explosive is carried to the building where it is loaded into caps.

Figure 97. Manufacture of Detonators. (Courtesy Hercules Powder Company.) Charging the capsules. Each of the holes in the upper steel plate (charging plate) is of the right size to contain exactly enough explosive for the charging of one detonator. The mixed explosive is emptied onto the plate, the rubber-faced arm sweeps the material over the charging plate filling all the holes and throwing the excess into the box at the right. Under the charging plate is the thin indexing plate which supplies a bottom to all the holes in the charging plate. The detonator capsules, s<*en at the left, are placed under the indexing plate and in line with the holes in the charging plate; the indexing plate is then removed, the explosive falls down into the capsules, cxactly the right amount into each, and is later pressed inlo place.

as they differ in their composition. No. 6, 7, and 8 caps arc the only ones which arc manufactured regularly in the United States, and the No. 6 cap is the one which is most commonly used.

The fulminate in detonators was first modified by mixing it with black powder, then with potassium nitrate, and later with

Was this article helpful?

0 0

Post a comment