Apparatus for Determining the Rate of Pressure Change for Starter Compositions

This apparatus is used to study the burning characteristics of fuel-rich compositions such as lead dioxide-cupric oxide-silicon starter mix systems and related delay mixtures. Starter compositions are used to initiate a variety of pyrotechnic systems, for example flame and smoke markers. Factors that determine the behavior and predictability of the system are defined and investigated by calorimetry, pressure-time curve studies and other techniques. The burning characteristics are used to ensure optimum performance of the starter composition.

The apparatus consists of a vessel equipped with a 500 psig pressure transducer. The vessel has a 90 ml working volume when loaded with a sample holder containing 12 grams of sample. The stainless steel sample holder is one inch high by 1.75 inches OD with a wall and bottom thickness of 0.125 inch. Ignition of the sample is by means of a Parr 2901 ignition unit which heats a 10 cm length of Parr 45C10 ignition wire to incandescence. The wire just touches the center of the sample. Changes of pressure are recorded on a computer via a USB interface at speeds up to 1000 readings per second.