Back to results
US 5,208,419 AGranted
Shock tubing that is IR transparent color-coded
AssigneeICI Canada Inc.
InventorsRobert C. Greenhorn, Jacques Lafond
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeICI Canada Inc.
InventorsRobert C. Greenhorn, Jacques Lafond
Estimating the term…
A method of producing a coloured shock tubing comprising a visibly coloured hollow tube having an inner coating of a reactive material wherein the core loading of the reactive material in the tube may be measured by radiation absorption. The visible colouration of the hollow tube is effected by the addition of a coloured compound, which compound is essentially transparent to the radiation used to measure core loading. A one stage extrusion process may be utilized to prepare a shock tube wherein core loading is easily measured during production, and verified after production.
A method of producing shock tubing, which shock tubing has a hollow tube with an inner core loading of a reactive material for the propagation of a shock wave within said tube, and which reactive material absorbs radiation of a selected frequency, which process comprises:
A shock tube comprising an inner surface and an outer surface, said inner surface coated with a core load of reactive material said shock tube characterized by the improvement comprising a colored hollow tube essentially transparent to IR or near IR radiation.
A method of producing shock tubing, wherein said shock tubing comprises a hollow tube, an inner surface and an outer surface, said inner surface coated with a core load of reactive material comprising the steps of:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Fuses, e.g. fuse cords: detonating fuses
Explosive and thermic compositions or charges: tagged compositions for identifying purposes
Detonating or priming devices
Technical subjects covered by former uspc cross-reference art collections [xracs] and digests
Term ended 1 May 2011 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to shock tubing and, more particularly, to a method of producing coloured shock tubing that facilitates measurement of core loading.
Persson, in U.S. Pat. No. 3,590,739, first described hollow tubes containing an inner coating of a reactive material, such as a pyrotechnic or explosive composition, which could be used to support the propagation of a gaseous percussion wave throughout the length of the tube. These hollow tubes, commonly known as shock tubes, are widely used by the explosives industry as a non-electric means to cause the initiation of non-electric detonating caps, and thus to cause the ignition of a main explosive charge.
Shock tubes are typically produced by the continuous extrusion of a polymeric resin into a flexible, hollow tube. The inside surface of the tube is coated with a suitable reactive material, which reactive material adheres to the surface of the tube. The tube may be subsequently stretched in order to increase its length.
The invention will now be described, by way of example only, with reference to the following figures, wherein:
FIG. 1 is a cross-sectional drawing of a single layer shock tubing according to the present invention;
FIG. 2 is a schematic drawing of a production facility to produce the shock tubing described in FIG. 1; and
In FIG. 1, a shock tube 10 is shown having a single wall hollow tube 11 having an inner coating of a reactive material 12.
Tube 11 is coloured and comprises a mixture of 80% linear low density polyethylene (LLDPE), 10 % of a low functionality ethylene-vinyl acetate resin (EVA) having 2% vinyl acetate, and 10% ethylene-acrylic acid. The tube is coloured by the addition of a yellow disazo dye, as a coloured compound, to produce a yellow hollow tube.
The reactive material 12 comprises a mixture of HMX (cyclotetramethylene tetranitramine) and aluminum. Reactive material 12 absorbs IR radiation from an IR radiation absorption means having a frequency peaking at 900 nm while coloured tube 11 does not absorb sufficient IR radiation at the stated frequency to substantially interfere with the measurement of the IR absorption of the reactive material.