A fire-resistant cord or OSH, sometimes a Bickford cord, is used to transmit a pulse into the distance in the form of a flame beam. Fire-retardant cord is a flexible braid of cotton (linen) threads or a sheath of polymeric material (plastic) containing a light-pressed core of fine-grained smoke powder. The braid is coated with a moisture-proof compound.
Flame retardant cord, stopin, wick, detonating cord, detonators, purpose and device.
The main types of flame retardant cord are:
OSP, flame-retardant plastic cord (coated with PVC) has a white shell color.
OSHDA, fireproof double asphalt cord (gray-black).
OSHA, fireproof cord asphalted (gray-black).
The fire-resistant cord has an outer diameter of 5.6 mm, the burning rate at atmospheric pressure is about 1 cm / s (under water, the cord burns faster). OSHP and OSHDA cords have enhanced moisture insulation and are used for working in humid environments and under water. OSHA cord has less reliable moisture insulation and therefore is used only in dry places.
Fire-resistant cord OSHP.
To carry out blasting operations using a flame-retardant cord, incendiary tubes are used, consisting of a radiation capsule-detonator (usually No. and a section of the flame-retardant cord inserted into it.
OSHDA fire-resistant cord.
When igniting a fire-resistant cord, ordinary or special matches and mechanical igniters are used. When using matches, the free end of the cord is cut obliquely (at an acute angle). Before use, the burning speed of the flame-retardant cord must be checked on a 60 cm length section, which should burn in 60-70 seconds.
Stopin, appointment and device.
Stopins are used to transmit a flame beam in artillery shells with special equipment (for example, incendiary shells). Stopin consists of cotton threads soaked in potassium nitrate. Outside, the threads are covered with a powder dough consisting of gum arabic, water and powder pulp. The threads are glued in the form of a tape 2.5-3 mm wide. The burning speed of stopina in the open air is about 3.5 cm / s.
Wick, purpose and device.
The wick is used as a means for igniting a fire wire cord. The core of the wick consists of flaxseeds impregnated with a solution of potassium nitrate. The burning speed of the wick is 1.2 cm / s.
Detonating cord, purpose and device.
The detonating cord (LH) is designed to transmit an explosive pulse to a distance. The detonating cord is a flexible shell of a triple filament braid or a polymeric material containing a pressed core with a detonating composition of blasting explosive. The shell is coated with a moisture insulating mass..
To equip the detonating cord, ten, tetryl, and other blasting explosives are used in powder form (slightly densified) or in the form of compressed tablets (tablet detonating cords).
In military affairs, a Tenn detonating cord of the DSh-B and DSh-V brands is used. Cord DSh-V has enhanced moisture insulation and can be used for work in water and damp places. Its shell is red. Cord DSh-B has less reliable moisture protection and is used in dry places. Red threads are woven into the shell of the DSH-B cord.
The outer diameter of the standard detonating cord is 5.6 mm, the detonation speed is 6500-7000 m / s, the mass of the explosive is 11-13 grams per 1 meter of length. The detonating cord is detonated by a detonator capsule or an electric detonator attached to the free end of the cord. One detonator capsule can explode up to six ends of detonating cord segments. There should be detonator caps at the ends of the cord sections inserted into the subversive charge checkers..
Detonators, purpose and device.
Detonators are a means of amplifying an explosive pulse in those cases when the pulse power of the primary detonator capsule is insufficient for a reliable explosion of the main charge. They are used in fuses, shells and others and consist, as a rule, of one blasting explosive placed in a glass, cup, etc. device.
Often, for a more reliable detonator response, systems use an intermediate transfer charge, which is placed between the detonator capsule and the main detonator.
Based on the book Explosives and gunpowder.
A.N. Kalyazhenkov, D.P. Malgin.