Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
  • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
  • B05B5/047—Discharge apparatus, e.g. electrostatic spray guns using tribo-charging
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
  • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
  • B05B5/035—Discharge apparatus, e.g. electrostatic spray guns characterised by gasless spraying, e.g. electrostatically assisted airless spraying
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B1/00—Engines characterised by fuel-air mixture compression
  • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
  • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder

Definitions

• This invention relates to a spraying apparatus particularly but not necessarily exclusively for spraying plants with fungicide, insecticide and the like.
• Conventional plant sprayers of one kind comprise a motor driven centrifugal blower which blows air through a flexible pipe of relatively large bore (i.e. of the order of 50 mm diameter).
• Liquid insecticide is led to the flexible pipe through a feed pipe which is connected to a tank for holding the insecticide.
• the insecticide is fed through the feed pipe either by gravity, by putting the tank under the low air pressure generated by the blower, by venturi effect or by a combination of these.
• As the liquid enters the flexible pipe it forms into droplets which are entrained in the air stream.
• the size of the droplets emitted from a conventional plant sprayer is of the order of 250 to 400 microns.
• plant spraying apparatus comprises at least one atomiser and means to pump liquid plant spray through the atomiser at high pressure, the atomiser being such that the plant spray pumped therethrough emerges as a mist the average droplet size of which is not greater than 100 microns.
• a method of plant spraying includes the step of pumping a liquid plant spray through an atomiser under high pressure to form a mist the average droplet size of which is not greater than 100 microns.
• Liquid plant sprays include fungicides, insecticides, herbicides and the like but are not necessarily limited thereto.
• High pressure means pressure which is high enough to cause a plant spray pumped through an atomiser of orifice size between .18 mm and .60 mm diameter to emerge as a mist having a droplet size of between 5 and 100 microns.
• An atomiser with an orifice size of less than about .18 mm would probably be too expensive except for special purposes and equally a pump required to pump at a pressure high enough to produce droplets smaller than 5 microns would be too expensive to be commercially useful for ordinary plant spraying work.
• the apparatus of the invention will include a pump which will operate at a pressure of about 130 bar but it is believed that, to be useful for ordinary plant spraying, the minimum pressure at which the pump should be capable of operating under ordinary conditions should be about 120 bar. Under special conditions or for some purposes however, a pump operating as low as 60 bar and as high as about 200 bar might still be useful for plant spraying.
• the apparatus of the invention will thus operate without the use of an air stream to draw the liquid through the atomiser. Also, since the apparatus does not use air to entrain the atomised spray.
• the apparatus includes a small bore flexible hose at least downstream of the pump.
• the hose is of hose material such as nylon which induces an electrostatic charge in the spray. Any other suitable hose material having the same effect may of course be used and the hose may be reinforced to enable it to sustain the operating pressure.
• droplets are formed which are substantially smaller than the droplets formed by conventional sprayers.
• the average size of the droplets produced is of the order of 5 to 60 microns. However, it might be useful for some purposes to achieve an average droplet size of up to about 100 microns.
• the apparatus may comprise a wand or other distribution member having a number of atomisers, i.e. at least two but even three or more atomisers. This is made possible by the efficient action of the mist in enveloping the plants to which it is directed combined with the considerably reduced quantity of plant spray which passes through each atomiser per unit time.
• a tank 10 containing liquid fungicide or insecticide is connected by a low pressure pipe 12 to, for example, a triplex (i.e. three stage) plunger pump 14 driven by a directly connected petrol engine.
• the pump and engine may be supplied as a single unit and are not separately shown on the diagram.
• a high pressure pipe 16 connects the outlet of the pump 14 to a regulator valve 18 provided with a pressure gauge 20 and a by-pass line 22 for returning excess liquid to the tank.
• the outlet of the regulator valve 18 is connected by a flexible, reinforced, high pressure nylon hose 24 to a rigid wand or boom 26 provided with, in this case, three liquid atomisers 28.
• the tank 10 is a standard size tank of capacity to suit the size of the apparatus. For example, if the apparatus is intended to be carried on the back of the user the tank may have a capacity as low as 10 litres. On the other hand a tractor mounted apparatus may have a tank of 1500 litres capacity. It is important that the tank should not be too large since suspended materials in the liquid may have a tendency to settle if the liquid remains in the tank for too long after the tank is filled or if the tank is not provided with an agitator.
• the pipes 12, 16 and 22 may be rigid or flexible as desired.
• the pump 14 in one working example is a Speck ⁇ ⁇ pump, model #NP 12-12-130. This pump has a rated working pressure of 130 bar and the output of this apparatus was about 3 litres per minute. Whatever pump is used it must of course have a delivery capacity matched to the capabilities of the apparatus. The capacity of the pump may be as low as 1 litre per minute for a back mounted apparatus and as high as 76 litres per minute for a tractor mounted apparatus.
• the regulator valve in the same working example is also known per se, being a model #UL 150, also marketed by SpeckTM.
• the pressure valve controls the pressure and rate of delivery of the liquid to the atomising nozzles.
• the atomising nozzles may also be of commercially available type as used in airless paint spraying equipment.
• the nozzle size can be chosen to suit the characteristics of the liquid and the size of droplet required.
• the droplet size is determined at least in part by the disease or pest for which the plants are being sprayed.
• the orifice size of nozzles most commonly used in the present apparatus will probably be .28 mm to .58 mm diameter.
• the average droplet size of a mist produced by pumping a liquid insecticide through a wand with three nozzles of .38 mm orifice size was determined to be 40 microns.
• the test comprised passing a glass microscope slide through the mist and determining the average size of the droplets which adhered to the glass.
• a hand held wand may comprise two, three or even more atomising nozzles.
• a tractor mounted boom may comprise as many as thirty five atomising nozzles.
• the atomising nozzles are of tungsten carbide or other material which is resistant to the abrasion of solids suspended in the liquid.
• One advantage of the apparatus is believed to be that such solids tend to be broken up as they pass through the high pressure filters with which such nozzles are provided. Filters of this kind are commonly of stainless steel gauze and again are well known in airless paint spraying equipment.

Landscapes

• Catching Or Destruction (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)
• Fertilizers (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=19922582

Family Applications (1)

Country Status (5)

Cited By (1)

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Citations (3)

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• 1990
  • 1990-03-09 AU AU52768/90A patent/AU5276890A/en not_active Abandoned
  • 1990-03-09 EP EP19900904732 patent/EP0474635A4/en not_active Withdrawn
  • 1990-03-09 WO PCT/AU1990/000102 patent/WO1990010505A1/en not_active Application Discontinuation
  • 1990-03-09 CA CA 2049026 patent/CA2049026A1/en not_active Abandoned
  • 1990-03-09 JP JP50470590A patent/JPH04506472A/ja active Pending

Patent Citations (3)

Non-Patent Citations (1)

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