Fluid sprinkling – spraying – and diffusing – Processes – Including dissolving or entraining in liquid stream
Patent
1991-12-05
1993-04-20
Kashnikow, Andres
Fluid sprinkling, spraying, and diffusing
Processes
Including dissolving or entraining in liquid stream
239 62, 239308, 239322, 239323, A01M 700, A01C 2304, B05B 732
Patent
active
052035042
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the mixing of liquids for agricultural purposes and more particularly to the preparation of spray liquids and nutrient solutions.
Liquids for agricultural purposes are often prepared by diluting a concentrate with water. Spray liquid is generally prepared by adding a small quantity of active ingredients in liquid form to a large quantity of carrier liquid, usually water, in a tank on the sprayer. It is important to produce a spray liquid which has the correct proportion of active ingredient so that the expected action, be it pesticidal, herbicidal or other, is obtained. Furthermore it is important to apply the correct quantity of spray liquid uniformly to a given area. All of the prepared spray liquid will usually be used in spraying but if spraying has to be interrupted or an error is made a quantity of spray liquid can remain and is not easily disposed of. For legal and environmental reasons the traditional technique of adding the active ingredient to a tank of water is thus no longer an acceptable one.
Proposals have been made for equipment which continuously adds the active ingredient to the carrier liquid as this is pumped to the spray head. In this way many of the problems of the traditional technique outlined above are in theory overcome. However the continuous addition of active ingredient is not easy. The active ingredient is often a very "aggressive" chemical, either itself or because of the solvent used, the mixing ratio required can vary over a wide range and the flow rate will have to vary with sprayer speed over the ground, while the carrier liquid can be at a high pressure, usually several bars.
Nutrient solutions are subject to similar requirements, the major one being generally the correct concentration.
Among proposals for continuous mixing are the use of diaphragm pumps driven at controlled speed to pump the active ingredient into a mixing device (Walsh Manufacturing company) and the use of a metering device driven by ground wheel to inject the active ingredient from a storage tank pressurised with compressed air (Terramatic). These proposals require pumps or like devices to handle the active ingredient, with all the problems this incurs.
SUMMARY OF THE INVENTION
It is an object of the invention to overcome the problems of preparing agricultural liquids by mixing.
According to the invention there is provided a method of preparing mixed liquids including: providing a supply of carrier liquid for utilisation, providing a supply of an active ingredient liquid for introduction into the carrier liquid in supply to the utilisation means, applying a displacement medium to displace the active liquid and introduce it into the carrier liquid, measuring and controlling the application of the displacement medium to produce a mixed liquid of specified proportions.
The controlling of the displacement medium may be open loop, that is to a set level, or closed loop, for example to maintain a required proportion in response to a sensor.
The utilisation means may include a sprayer or a nutrient film equipment.
The displacement medium may be carrier liquid from the supply. The volume of displacement medium applied may be controlled in accordance with control signals representing the demand for spray liquid when the utilisation means is a sprayer. The control signals may include at least one of required concentration of active ingredient, required spray liquid flow, sprayer size and speed over the crop.
According to the invention there is also provided a method of preparing a mixture of a carrier liquid and an active liquid in required proportion including: providing a flow of carrier liquid, controlling a liquid flow to an appropriate proportion of said carrier liquid flow from pressure drop measurements of the proportional liquid flow, displacing active liquid with said proportional liquid flow without liquid contact, including said displaced active liquid in said carrier liquid flow, thereby producing a liquid mixture in said required proportion without a flow meter.
Accordin
REFERENCES:
patent: 2323618 (1943-07-01), Ottoson
patent: 4406406 (1983-09-01), Knapp
patent: 4721245 (1988-01-01), Van Zweeden
patent: 4858830 (1989-08-01), Proctor et al.
patent: 4875626 (1989-10-01), Buhler et al.
Frost Andrew R.
Marchant John A.
British Technology Group Limited
Kashnikow Andres
Merritt Karen B.
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