EP0855225A1 - Anti-foaming device for sprayer, especially of the agricultural type - Google Patents

Abstract

The device takes surplus liquid returned to a main tank (1) through a spray bar (11) with a large number of small orifices (12). The bar delivers the liquid at low pressure in a multiplicity of low-velocity jets, so that it falls into the tank in the form of a fine rain. Alternatively, the surplus liquid can be returned to the tank via a distributor in the shape of a watering can rose with small outlets covering a large surface area, or through an intermediate chamber at the top of the tank which has a large number of small holes in its base.

Description

The present invention relates to an anti-foam device for sprayers, especially agricultural.

We know that we have to treat crops in spraying natural liquids on the ground or on plants various in the form of mist or fine droplets.

Spraying devices of known types include generally a tank from which the liquid to be sprayed is taken to send it under pressure in pipes which result in spray nozzles.

Generally, to ensure sufficient pressure at the level spray nozzles use a pump with a flow rate which is much higher than the flow rate of the spray nozzles, the excess liquid being recycled to the main liquid tank via a valve calibrated according to the pressure at which one wishes to carry out the spraying.

We know in particular from US-A-3,784,100 a spray device in which excess liquid is brought back into the tank by means of a submerged ramp placed in the bottom of the tank and provided with openings directed upwards, for create high speed jets tending to homogenize the liquid.

We also know by the European patent application EP-A-0 405 244 a similar spraying device.

In a certain number of cases, the liquid thus brought back to the main tank has a marked propensity to form foam which accumulates there which constitutes a major annoyance when it is necessary to refill the tank.

The present invention aims to eliminate this drawback.

The subject of the present invention is a device for preventing foaming in the main tank of a sprayer, especially agricultural, which is characterized by the causes the liquid to return to the main tank by a device which has a large number of small orifices separate which cause excess liquid to fall into the reservoir main at low pressure and in the form of a multitude of low speed jets.

This multitude of jets can be obtained either using a or more sprinkler-type dispensers that include a large number of small orifices over a large area, i.e. in the form of ramps which have a large number of small orifices arranged in line, possibly being grouped at many from far and wide.

In a variant, it is possible to carry out at the party upper tank a chamber whose lower wall has a large number of small holes and in which the liquid recycled is sent so that it falls into the tank main in the form of a fine rain.

According to the invention, it is necessary that the section total of the small holes is sufficient for the jets of the liquid flowing back into the main tank takes place at low speed.

It can be seen that, thanks to the invention, the recycling of the liquid in the main tank without any significant training foam, which provides good visibility at all times the contents of the tank and allow it to be filled without being hindered by the foam which forms with known devices.

When recycling excess liquid is used to stir the liquid in the tank to keep it its homogeneity, it is according to the invention to divide the liquid recycled in two streams, one being sent to the main tank for homogenization, while the other is sent into the device anti-foam according to the invention.

In order to better understand the invention, we will describe now for illustration and without any character limiting an embodiment taken as an example and represented on the drawing, the single figure of which represents a schematic view of a agricultural spraying device according to the invention.

We see in the single figure the main tank 1 containing the spray liquid 2. We have schematically represented by a broken line 3 a running gear which supports tank 1.

At the bottom of the tank 1 is a pump 4 sending under pressure into line 5 the liquid of spraying which ends in a ramp 6 arranged perpendicular to the plane of the figure, this ramp 6 has a plurality of nozzles which send jets 7 of fine droplets in direction of plants 8 which are arranged on the ground.

Line 9 returns to main tank 2 the excess liquid which is not distributed by the nozzles of spray 6.

The spraying pressure is determined by a valve discharge 10 suitable tared to open only when the pressure in line 5 exceeds the desired value.

Schematically shown inside the tank 1, a ramp 11, provided with orifices 12 directed downwards and situated at the above the level of the liquid in the tank 1, which cause the liquid which flows back into tank 1 falls there without pressure and without notable speed in the form of a fine rain, which avoids the foaming inside the tank.

Alternatively, the ramp 11 can be replaced by a plurality of sprinkler heads that have on one surface relatively large a large number of small holes so spraying the back-flowing liquid without giving it pressure and a significant speed.

It is understood that the embodiment which has been described above is in no way limiting and that it will be able to receive any desirable modifications without leaving for that of the scope of the invention.

In particular, it is clear that the embodiment which has shown in the drawing is purely schematic and that the various organs can be produced in the forms and in different positions.

Claims (6)

Device to prevent the formation of foam in the main tank of a sprayer, in particular agricultural, characterized by the fact that the return of the liquid in the tank main (1) is carried out by a device (11) which has a large number of small separate orifices (12) which return the liquid in excess in the main tank at low pressure and under the forms a multitude of low speed jets. Device according to claim 1, characterized by causes said ports to be arranged so that the liquid which flows back without pressure and without notable speed in the form of fine rain in the tank. Device according to claim 1 or 2, characterized by the fact that the excess liquid is returned to the tank main (1) by at least one ramp which includes a large number of small orifices (12) arranged in line or which are possibly grouped together from far and wide. Device according to claim 1 or 2, characterized by the fact that the excess liquid is returned to the tank main (1) through at least one distributor of the type watering can head which has a large number of small holes on a large area. Device according to claim 1 or 2, characterized by the fact that the liquid is returned to the main tank (1) by through a chamber placed at the top of the tank and comprising in its lower wall a large number of small holes. Device according to any one of Claims 1 to 5, characterized by the fact that only part of the recycled liquid is sent to the anti-foam device, the rest being used to homogenize the liquid contained in the main tank.

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