Liquid projectile launcher

Details Liquid projectile launcher Liquid projectile launcher

1998-07-10

2001-04-24

Lavinder, Jack W. (Department: 3644)

Ordnance

Accelerating

Reexamination Certificate

active

06220141

ABSTRACT:

BACKGROUND TO THE INVENTION
A number of applications clearly show that water droplets projected at high velocity can retain their integrity until impacting on a desired target a selected distance away. For example, cutting machines using high pressure air and/or water jets have been successfully used for many years. Vaccination guns based on hydraulic propulsion have also become commonplace. Due to the number of conversions prior to application, energy is, however, not always utilised efficiently.
Direct energy conversion from electrical to kinetic has been applied in the case of metallic projectile launchers utilising a successively pulsed array of solenoid coils to provide the requisite accelerating force. It has also been applied in conjunction with a water propellant to effect the discharge of a small gun—the water first having been made conductive by the addition of salt—and by passing through an electrical current to bring about an electric arc, thereby promoting the requisite surge of electric current required to eject a solid projectile from the barrel at high velocity.
A water-arc launcher utilising this principle is described in a magazine article by Peter Graneau. Electronics and Wireless World, June 1989, pp 556-559. However, the side-mounted current connector in this version results in pronounced asymmetry in the axial current flow upon launching, causing the liquid charge to scatter widely upon emerging from the barrel, and thereby rendering the device ineffective for use as a globular liquid projectile launcher. The use of a solid projectile in conjunction with the water charge incorporated in the water gun featured in this article is also somewhat impractical. While the water charge amounts to a rather modest 3.8 g, the energy requirement to propel the total charge at 1000 meters per second would necessitate capacitor charge to a voltage sufficient to sustain an electric arc, amounting to a half to a full farad of capacitance, and capable of discharging in sizable fractions of 100 kA. This would weigh many kilograms, and make equipment based on this type of approach too heavy for use in applications requiring a high degree of portability.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a fluid projectile launcher comprising a barrel having an open end and a closed end defining a breech portion arranged to hold a dosage of fluid, and a launching initiation circuit including energy storage means, energy application means forming part of the breech portion, symmetrical thrust-generating and perpetuating means, and trigger means for allowing the energy storage means to discharge into the dosage of fluid in the breech portion via the energy application means so as to cause the dosage of fluid to be symmetrically thrusted from the open end of the barrel as a fluid projectile.
Preferably, the energy application means includes first and second electrodes which are insulated from one another bar their individual electrical connection via the dosage of fluid, and which are symmetrical about a central axis of the barrel, the energy storage means includes a capacitor, and the symmetrical thrust generating and perpetuating means includes an array of electrical leads connected symmetrically to the first and second electrodes relative to the central axis of the barrel so as to create an electromagnetic field which is functionally symmetrical in a plane normal to the central axis of the barrel.
Conveniently, the breech portion is dimensioned and the energy application means is positioned to accommodate a fluid dosage having a maximum mass of 1 gram.
Advantageously, the breech portion includes a tubular electrically conductive portion defining the first electrode, the second electrode comprises an electrically conductive pin substantially coincident with the central axis of the barrel and extending into a base of the breech portion, and the array of electrical leads including at least a first pair of leads connected equi-angularly in a radially symmetrical pattern around the tubular first electrode and a second lead connected to the second electrode.
The invention extends to a fluid projectile launcher comprising a barrel having an open end and a closed end defining a breech portion arranged to hold a dosage of fluid, and a launching initiation circuit including energy storage means, energy application means forming part of the breech portion, and trigger means for allowing the energy storage means to discharge into the dosage of fluid in the breech portion via the energy application means so as to cause the dosage of fluid to be launched from the open end of the barrel as a fluid projectile, the breech portion being dimensioned and the energy application means being positioned to accommodate a fluid dosage having a maximum mass of 1 gram, preferably having a maximum mass of 0.5 grams, and more preferably having a maximum mass of 0.1 grams.
Typically, the energy storage means includes a capacitor and an inductance for controlling the rate of discharge of arc current across the first and second electrodes, the arc current having a waveform including at least one half sinusoid.
The waveform of the discharge arc current may include a plurality of half sinusoids defining at least one damped oscillation.
Preferably, the launching initiation circuit includes a pair of input terminals arranged to be connected to a power supply, and conditioning means for conditioning the power from the power supply, the conditioning means including a voltage multiplying rectifier.
The fluid projectile launcher may be in the form of a portable hand-held device including a handle, and the trigger means includes a sliding switch having a pair of fusible contacts, and a separator for prying open the contacts after use.
The barrel may have a diameter from 2 mm to 3.5 mm.
According to a still further aspect of the invention there is provided a primed fluid projectile launcher comprising a barrel having an open end and a closed end defining a breech portion holding a dosage of fluid, and a launching initiation circuit including energy storage means, energy application means forming part of the breech portion, and trigger means for allowing the energy storage means to discharge into the dosage of fluid in the breech portion via the energy application means so as to cause the dosage of fluid to be launched from the open end of the barrel as a fluid projectile, the dosage of fluid comprising an ionising medium for rendering the fluid electrically conductive and an active substance which induces a physiological reaction in living organisms.
The active substance may include at least one of the following, namely a drug, a plant or animal protection agent such as a vaccine or insecticide, a nutrient, a poison, a pain-inducing substance, or a disabling agent.
The invention extends to a method of inducing a physiological reaction in a living organism including the steps of providing a fluid projectile launcher comprising a barrel having an open end and a closed end defining a breech portion, and a launching initiation circuit including energy storage means, energy application means forming part of the breech portion, and trigger means, loading the breech portion of the fluid projectile launcher with a dosage of fluid, the fluid including an ionising medium for rendering the fluid electrically conductive and an active substance which induces a physiological reaction in the living organism, aiming the liquid projectile launcher at a target defined by the living organism, and activating the trigger means so as to allow the energy storage means to discharge into the dosage of fluid in the breech portion via the energy application means so as to cause the dosage of fluid to be thrusted from the open end of the barrel as a fluid projectile.
The method may include the initial step of charging the energy storage means from an external power supply.


REFERENCES:
patent: 5331879 (1994-07-01), Loffler
patent: 0242501 (1987-10-01), None

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