Piped match

Whilst quickmatch can be used to form simple fuses for fireworks, both internally and externally, a burning time of some 40 sm is too long in instances when a more or less instantaneous ignition is required. Also, quickmatch is rather fragile and tends to kink or lose powder unless it is coated in some way. 

If one recalculates the rate of burning using equation (10.1) with a revised ambient pressure of, say, 100 psi to reflect conditions inside the 

Obviously, the flame must be free to travel within the confines of the pipe but at a rate which produces an acceptable pressure increase without bursting the pipe. 

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T/, = thickness of pipe matching run of tee or header excln- sive of reinforcing elements, in (mm)... 

Whilst it is apparent that the gunpowder substitute has been developed for use in munitions, it remains to be seen whether the material can be used to the same extent in hreworks. Obvious applications would be as replacements for quickmatch and piped match, both of which are notoriously prone to dampness during wet or humid conditions. 

Initially the main piped match fuse is lit and a fraction of a second later the flame from this fuse reaches the gunpowder lift charge in the bag at the base of the shell. 

The gunpowder explodes in a further fraction of a second, the explosion blowing the shell out of the mortar tube in the manner of a shot from a cannon. At the same time a return section of piped match is lit by the explosion, transferring flame back to the top compartment where it reaches the quickmatch placed across the head of the 25 mm pressed delay fuse. 

The larger Roman candles are htted with plastic end-caps in the obvious interest of waterproofing, and the fuses are extended to include a piped match and a delay fuse. Display hreworks are often arranged as fans on a wooden framework (Figure 8.4) or wrapped as bundles with an interconnecting fuse. 

Figure 10.1 Wirebridge fusehead (bottom), quickmatch (middle) and piped match (top).

Experiments have confirmed that there is an optimum fuse-to-wall distance in piped match where the burning rate is at a maximum, and this effect is presented graphically in Figure 10.2. 

Plastic fuse is routinely used as a fuse extension to quickmatch or piped match, especially when firing rockets, mines or shells. In the latter case, the piped match fuses from a crate of, say, ten shells connected via a single length of plastic fuse which will burn progressively to ignite each of the ten shells in turn. 

A more recent and improved means of timing the ignition of piped match is provided by an Italian product called PYROCLOCK. This is a modular system containing vented delay elements with burn times of 1.0, 1.5, 2.0, 2.5, 3.0, 4.0 and 5.0 seconds. 

Each water resistant tubular unit contains an open ended piped match holder, a time delay element and a holder at the opposite end of the tube for an electric igniter (or a second PYROCLOCK element). 

The lances are then matched using interconnecting piped match and plastic tape or wire, taking care to ensure that each section of piped match directly above a lance is pricked to create a vent-hole. Otherwise, the force from the ignition of the match can blow it clear of the lance before the hrework has been successfully ignited. 

PIPED MATCH A fuse Consisting of quickmatch enclosed in a paper pipe that serves to increase the burning speed. 

PYROCLOCK A modular system of vented delays with a range of burn times which form robust fuses. May be used for connecting to piped match or similar for the timed firing of shells etc. 

Quickmatch becomes a nearly instantaneous transfer line if enclosed in a narrow paper tube and is thus used under the name of Piped Match in fireworks for simultaneous initiation of several items (Ref 57, p 191)... 

How another piece of kraft paper is cut to a also big enough to wrap around tha shell a couple of times and extend outward about three inches at both ends of the shell tbe else for cutting these abeete for additional shells of the same dimensions can be determined after tbe following operations Tbe sheet should be wrapped and pasted down tightly over the shell and piped match, then checked against tbe mortar to be need for proper "windage". 

When preparing set pieces for a display, the most often-repeated operation is that of joining two pieces of piped match to convey fire from one to the other Thus, It Is one of the first skills the prospective fireworker should leam. Unfortunately, the literature has few if any exact descriptions of how this Important operation should be done, and the beginner must first learn it on the job. It is hoped that the following Instructions will help in preparing him to make failsafe splices quickly end efficiently at his first display. 

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