Targeting of flying insects with insecticides and apparatus for charging liquids

A spray device which is capable of imparting by double layer charging and charge separation to liquid droplets of a composition sprayed therefrom a unipolar charge resulting in a charge to mass ratio of at least +/−1×10−4 C/kg, which spray device comprises:

• i) reservoir for accommodating the liquid composition;
• ii) a spraying head through which the liquid is expelled in the form of a spray of droplets;
• and
• iii) a conduit system for feeding the composition from the reservoir to the spraying head;
• wherein
• a) the spraying head has a bore through which the liquid is expelled from the device, the bore having an outlet having an L/a ratio of at least 10, where L is the length of the periphery defining the bore outlet in mm and a is the cross sectional area of the bore outlet in mm2;
• and
• b) the device is constructed such that the droplets are expelled from the spraying head at a flow rate of at least 0.5 grams per second and have the aforementioned charge to mass ratio.

A spray device which is capable of imparting by double layer charging and charge separation to liquid droplets of a composition sprayed therefrom a unipolar charge resulting in a charge to mass ratio of at least +/−1×10−4 C/kg, which spray device comprises:

• i) a reservoir for accommodating the liquid composition;
• ii) a spraying head through which the liquid is expelled in the form of a spray of droplets;
• and
• iii) a conduit system for feeding the composition from the reservoir to the spraying head;
• wherein
• a) the spraying head has a bore through which the liquid is expelled from the device, the bore having an outlet having a tortuous periphery and an L/a ratio of at least 8, where L is the length of the periphery defining the bore outlet in mm and a is the cross sectional area of the bore outlet in mm2;
• and
• b) the device is constructed such that the droplets are expelled from the spraying head at a flow rate of at least 0.4 grams per second and have the aforementioned charge to mass ratio.

An aerosol spray device which is capable of imparting by double layer charging and charge separation to liquid droplets of a composition sprayed therefrom a unipolar charge resulting in a charge to mass ratio of at least +/−1×10−4 C/kg, which spray device comprises:

• i) a reservoir for accommodating the liquid composition;
• ii) a valve stem mounted for rectilinear displacement with respect to a tail piece;
• iii) an actuator for displacing the valve stem between a closed first position and an open second position in which said valve stem is in communication with the tail piece;
• iv) a spraying head located in the actuator in communication with the valve stem and through which the liquid is expelled in the form of droplets, said spraying head including a swirl chamber and a mechanical break-up device, and
• v) a conduit system for feeding the composition from the reservoir to the spraying head, said conduit system comprising the valve stem, the tail piece, and a dip tube connecting the tail piece to the reservoir, wherein
• a) the spraying head has a bore through which the liquid is expelled from the spray device, the bore having an outlet having a tortuous periphery and an L/a ratio of at least 8, where L is the length of the periphery defining the bore outlet in mm and a is the cross sectional area of the bore outlet in mm2;
• b) liquid is driven from the reservoir through the conduit system to a nozzle in the spraying bead by gas under pressure in the reservoir;
• and
• c) the spray device is constructed such that the droplets are expelled from the spraying head at a flow rate of at least 0.4 grams per second and have the aforementioned charge to mass ratio.