Delay compositions and detonation delay devices utilizing same

Abstract

A delay composition for a detonator or delay device. The composition comprising a mixture of silicon and barium sulfate, and an amount of red lead in the range of about 3 to 15%, and preferably 6 to 12%, by weight of the mixture. The invention also relates to a delay element comprising a rigid metal tube containing the delay composition, and a delay device incorporating the delay element.

1 . A delay composition comprising mixed particles of silicon, barium sulfate and red lead, the red lead being present in an amount of about 3 to 15% by weight of the composition.  
     
     
         2 . The composition of  claim 1  wherein the red lead is present in an amount of about 6 to 12% by weight of the composition.  
     
     
         3 . The composition of  claim 1  wherein the red lead is present in an amount of about 9 to 12% by weight of the composition.  
     
     
         4 . The composition of  claim 1  wherein the composition contains about 40 to 60% by weight of said barium sulfate and about 25 to 50% by weight of said silicon.  
     
     
         5 . The composition of  claim 1  further containing a binder causing collections of said particles to bind together in the form of free-flowing granules.  
     
     
         6 . The composition of  claim 5  wherein said binder is selected from the group consisting of solvent-soluble polymers, silica and swelling clays.  
     
     
         7 . The composition of  claim 5  wherein said binder is a water-soluble derivative of cellulose.  
     
     
         8 . The composition of  claim 5  wherein the binder is carboxymethyl cellulose.  
     
     
         9 . The composition of  claim 8  wherein said binder is present in an amount of 0.2 to 0.6% by weight of the composition.  
     
     
         10 . The composition of  claim 1  wherein the particles of barium sulfate have a specific surface area of about 0.8 m 2 /g, the particles of silicon have a specific surface area of 6 to 8 m 2 /g, and the red lead has a particle size of about 1 to 3 microns.  
     
     
         11 . A delay composition in the form of free flowing granules each consisting essentially of mixed particles of silicon, barium sulfate and red lead, together with a binder, the red lead being present in an amount of about 3 to 15% by weight of the composition.  
     
     
         12 . A delay element for a detonator or delay device, comprising an elongated hollow metal tube, containing a delay composition comprising mixed particles of silicon, barium sulfate and red lead, the red lead being present in an amount of about 3 to 15% by weight of the composition.  
     
     
         13 . The delay element of  claim 12  wherein the delay composition has a density in the range of 1.8 to 2.2 g/cc.  
     
     
         14 . The delay element of  claim 12  wherein the delay composition has a density of 1.95 to 2.15 g/cc.  
     
     
         15 . The delay element of  claim 12  wherein the metal tube is made of a rigid metal.  
     
     
         16 . The delay element of  claim 12  wherein the tube is made of a metal selected from the group consisting of zinc, aluminum, steel and brass.  
     
     
         17 . The delay element of  claim 12  wherein the tube is made of zinc.  
     
     
         18 . The delay element of  claim 12  wherein the delay composition further contains a binder causing collections of said particles to agglomerate together in the form of granules.  
     
     
         19 . The delay element of  claim 18  wherein said binder is selected from the group consisting of solvent-soluble polymers, silica and swelling clays.  
     
     
         20 . The delay element of  claim 18  wherein said binder is a water-soluble derivative of cellulose.  
     
     
         21 . The delay element of  claim 18  wherein the binder is carboxymethyl cellulose.  
     
     
         22 . The delay element of  claim 21  wherein said binder is present in an amount of 0.2 to 0.6% by weight of the composition.  
     
     
         23 . The delay element of  claim 12  wherein particles of barium sulfate have a specific surface area of about 0.8 m 2 /g, the particles of silicon have a specific surface area of 6 to 8 m 2 /g, and the red lead has a particle size of about 1 to 3 microns.  
     
     
         24 . The delay element of  claim 12  having a length corresponding to a burning delay of at least one second.  
     
     
         25 . The delay element of  claim 12  having a length corresponding to a burning delay of about 2 to 9 seconds.  
     
     
         26 . A delay element for a detonator or delay device, comprising an elongated hollow tube made of a rigid metal selected from the group consisting of zinc, aluminum, steel and brass, containing a delay composition in the form of free flowing granules each consisting essentially of mixed particles of silicon, barium sulfate and red lead, together with a binder, the red lead being present in an amount of about 3 to 15% by weight of the composition, and the element having a length corresponding to a burning delay of at least one second.  
     
     
         27 . A detonation delay device comprising a combustion starter, a charge to be detonated, and a delay element separating said combustion starter and said charge to be detonated, said delay element being an element according to  claim 12 .  
     
     
         28 . The detonation delay device of  claim 28  including non-electric means for igniting said starter.  
     
     
         29 . The detonation delay device of  claim 28  including electric means for igniting said starter.