Sheathed explosives

Sheathed explosives appeared very successful at their introduction, but... 

When explosives of the power shown in this table are prepared, the power per unit length of the explosive cartridge is similar to that of the power of a sheathed explosive made from a PI composition. Effectively, therefore, the difference between a P2 and a P3 explosive is that the inert material in the sheath of the former is distributed uniformly through the explosive composition of the latter. For reasons of stability, however, sodium bicarbonate is no longer used instead an increase in the proportion of sodium chloride gives the required cooling effect. 

P2. Originally called sheathed explosives, consist of PI explosives enclosed in a sheath to give increased safety. 

It is also evident that the increased safety produced by using sheathed explosives is lost if the sheath is removed deliberately. The latter may happen, for instance, if the hole into which the charge is being loaded is too narrow. 

In Great Britain an alternative solution was found. The inert material was directly and uniformly incorporated into the explosive itself, instead of forming a separate sheath (J. Taylor [66]). These explosives were marked Eq. S. , i.e. equivalent in safety to sheathed explosives of the same class. 

Sheathed explosives with an inert sheath, usually containing sodium hydrogen carbonate, are also employed. After World War II Eq. S explosives were introduced. These have already been mentioned (p. 429). 

Five shots, each of 20 oz inversely initiated without stemming. (In sheathed explosives the charge includes the sheath.)... 

Five shots directly initiated and stemmed with a 1 in. clay plug. For Eq. S. each shot is 36 oz and for sheathed explosives each shot is 28 oz (18 oz for low-density explosives.)... 

The test applied for sheathed explosives only consists of five shots, each of 8 oz directly initiated, and fired unstemmed. (The weight does not include the sheath.)... 

The power of sheathed explosive is tested using the sheath to cover a standard explosive composed of ... 

Pobedit P-8 is an ammonium nitrate sheathed explosive with 7% nitroglycerine. The sheath is composed of potassium chloride powder. 

Blanketed or Covered Explosives. See Enveloped Explosives, known as Sheathed Explosives... 

Core Explosives or Core Charges. In ordet to lower the temperature of explosion to the level of "permissible explosives, thus avoiding the ignition of firedamp and dust in coal mines, R.W. Lawrence of Hercules Powder Co proposed [USP 2565380(1951) CA 46, 1752(1952)] to place inside of an AN Dynamite cartridge a "core , which can be either hollow or consist of an "inert material, similar to that used for sheaths (See under Enveloped or Sheathed Explosives)... 

Under the term esplosivi con guaina or esplosivi inguainati are known as Italian enveloped or sheathed explosives (Refs 3 ... 

United States sheathed explosives are not listed in the DuPont sBlasters1 Handbook (1966), but are in other hooks listed in Vol 3 of Encycl, pp C455 to C459... 

EqS Explosives (Equivalent in Safety to Sheathed Explosives) (British). As was noted under the description of Enveloped or Sheathed Explosives, the EqS were developed in order to have expls which are safe tinder any cir cumstances. They were developed by J, Taylor and proved such a success that they replaced Sheathed Explosives in many cases. As was already mentioned they were prepd by incorporating a cooling agent in expl itself, Instead of using a shield. Compositions of the following EaS Exolosives Unirend Ifni pv... 

Esplosivi con guaina (Sheathed Explosives). Accdg to Dr Camillo Belgrano of Codroipo (Udine), as communicated to Dr Omero Vet-tori of Aulla (Massa Carrara), Italian sheaths consist of mixts of Ca fluoride and sulfate with Na bicarbonate. These expls have been used in Sicilian sulfur mines Ref Dr Omero Vettori, private communications July I and August 17,(1964)... 

Active Sheoth (Aktive Man tel pat rone). A type of sheath (see Sheathed Explosives), con sistg of flameless, gas-producing mixts capable of self-sustenance of their gas-producing character. These sheaths usually consist of NG(with/or without NGc) and inert ingredients, such as N all CO, NaCI, Kieselguhr, etc [See also PATR 2510( 1958), p Ger I ... 

Blanketing Compositions for Blasting Explo sives. See under Sheathed Explosives... 

Cased Charges or Cased Explosives. Any expl material confined in a case, which can be metal, plastic, cardboard, etc, may be so called. There is no book on this subject, but a number of reports, mostly of British origin. The confidential references listed below were not used as sources of info(Comp with Sheathed Explosives)... 

EqS Equivalent Sheathed (Explosive). An expl as safe as a sheathed expl of the same type... 

The previously mentioned "sheathed explosives" were introduced in GtBritain in 1934, after many sheathing materials were tried and rejected. Finally it was decided to use a sodium bicarbonate (and in some cases NaCl) sheath (Ref 49, pp 30-1)... 

Permissible expls include also sheathed explosives and core explosives, briefly described in this Section II before Belgian Permissible Explosives... 

Compex. One of the Brit "permitted mining expls which are designated as EqS (equivalent in safety to sheathed explosives). It is listed in Ref without giving the composition Ref Taylor Gay (1958), 96... 

Sheathed Explosives. See under Commercial or Industrial Explosives in Vol 3, C450-R to C459-R, Low Energy Detonating Cord (LEDC) in Vol 7, L58-L and Primacord in Vol 8,... 

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