Patent Description:
In the agricultural sector, devices are known to be combined with agricultural machines, such as for example seeders, transplanters, weeders and machines and equipment in general for the localized distribution of fluid products, according to programmed quantities. For this purpose, the agricultural machine is equipped with one or more tanks containing the fluid products to be distributed and with one or more dispensing units having a supply duct, which leads to a distribution chamber to feed it with the fluid to be dispensed, and a plurality of delivery ducts terminating with nozzles installed in the machine near the ground to deliver the treatment fluid in a localized manner.

The <CIT> describes a dispensing device for liquid products, in which each dispensing unit comprises a box-shaped body which defines an inspectable cylindrical distribution chamber, to which a central supply duct for the liquid to be dispensed and a plurality of ducts arranged around the central duct for dispensing the liquid itself to as many nozzles.

In order to avoid dripping of the liquid present in the cylindrical chamber and in the pipes when the flow of new liquid into the latter is interrupted, each delivery duct is provided at its end, which leads to the distribution chamber, of a small valve which is constituted by an elastic membrane presenting a cut with flaps that can be spread apart due to the effect of the pressure, with which the liquid to be distributed is introduced into the chamber itself, and automatically reachable when the liquid ceases to be introduced into it.

This known solution has solved a series of problems that the prior art presented but at the same time revealed a plurality of limitations that the present invention aims to overcome.

One of these limits consists in a certain manufacturing complexity of the device, which is provided with a valve for each of the delivery ducts, which can be even a few dozen per delivery unit.

Another limitation consists in the fact that the opening of each valve is caused by the pressure, with which the liquid to be dispensed is fed to the distribution chamber, and inevitably causes a pressure drop of the inlet liquid with respect to the outlet liquid. pressure which is all the more important the lower the working pressure is.

Another limitation consists in the fact that since the opening of each valve is determined by the elastic yielding of the membrane, with which the valve is made, an identical behaviour is not ensured for all the valves and therefore their identical opening at the same pressure of the adducted liquid. It follows that a uniform distribution of liquid on all delivery ducts is not ensured.

Another drawback consists in the fact that the valves are of delicate operation, they are sensitive to dirt and inevitable encrustations due to the liquid to be dispensed and require periodic maintenance which is all the more laborious the higher the number of valves present in the dispensing unit is.

The object of the invention is to eliminate all the drawbacks which jointly or separately are recognizable in the state of the art.

In particular, the object of the invention is to propose a device which is capable of delivering fluids through a plurality of ducts with a substantial uniformity of delivery through all these ducts.

Another object of the invention is to propose a device for dispensing fluids which is simple to manufacture and safe and reliable in operation.

Another object of the invention is to propose a device for dispensing fluids which allows to precisely regulate the opening and closing pressure of the dispensing through each duct.

Another object of the invention is to propose a device for dispensing fluids which excludes any risk of dripping during transfer over rough terrain.

Another object of the invention is to propose a device for dispensing fluids which ensures constant regular operation while requiring limited maintenance.

All these objects and others that will result from the following description are achieved according to the invention with a device for dispensing fluid products, as defined in claim <NUM>.

The present invention is further clarified hereinafter in some of its preferred forms of practice. embodiments reported for purely illustrative and non-limiting purposes with reference to the attached drawings in which:.

As can be seen from the figures, the device according to the invention is globally indicated with <NUM> and is intended to be installed alone or with similar devices in an agricultural machine, such as in particular a seeder, a transplanter, a weeder or any other machine, with which the fluid and in particular the liquid to be dispensed can be distributed in the soil or on the plants in a localized manner and according to the programmed dose.

For this purpose the device <NUM> is provided with a supply duct <NUM>, through which the fluid to be dispensed, contained in a tank supported by the frame of the agricultural machine and not shown, is transferred to the device <NUM>, and with a plurality of dispensing ducts <NUM>, through which the same fluid is brought to as many nozzles installed in the agricultural machine in suitable positions to be distributed in a localized form in the ground.

Moreover, since all this is well known to operators in the sector, it does not require a more detailed description.

The device <NUM> according to the invention comprises a cylindrical base <NUM> and a cover <NUM>, also cylindrical, which can be coupled together to define an expansion chamber <NUM>, better described below.

Inside the expansion chamber <NUM>, when the circuit is open, a distribution chamber <NUM> is formed, as better described below, between the upper surface of the base <NUM> and the lower surface of a membrane <NUM>.

The base <NUM> presents a central through hole <NUM> and a plurality of through holes <NUM> of smaller diameter arranged around said central hole <NUM>, preferably on one or more concentric circumferences.

A connection <NUM> for the supply duct <NUM> can be inserted in the central hole <NUM>.

Preferably, a pump (not shown) is interposed between the reservoir of the fluid to be delivered and the device <NUM> in the duct <NUM>, which has the function of supplying the fluid to the device <NUM> with a predetermined and possibly adjustable pressure.

The constraint between the connection <NUM> and the base <NUM> can be any and is linked to the nature of the material with which the base <NUM> is made. For example, if the base <NUM> is made of metal, it is preferable that the hole <NUM> has a threaded internal surface and the connection <NUM> has the portion to be inserted into the hole <NUM> which is also threaded, while if the base <NUM> is made of plastic material, it is preferable that the connection portion <NUM> to be inserted into the hole <NUM> presents a plurality of parallel circumferential ribs with a sawtooth profile, to be inserted by forcing into the hole itself.

In the holes <NUM> obtained in the base <NUM>, connections <NUM> can be inserted for the same number of delivery ducts <NUM>. The constraint between each connection <NUM> and the base <NUM> is also linked to the nature of the material, with which the base is made and can be similar to that of the connection <NUM>, that is, for example, for threaded coupling or for forced insertion. The distribution chamber <NUM> has a diameter such as to have its circumferential edge external to all the through holes <NUM> obtained in the base <NUM>.

The cover <NUM> extends from the opposite side with respect to the base <NUM> in a cylindrical sleeve <NUM>, which can be made in the body single with the cover <NUM> or it can be made in a separate piece, joined to the cover <NUM> by means of screws <NUM>, as shown in the drawings.

The sleeve <NUM> externally presents a thread <NUM>, to which a knob <NUM> can be screwed, and is internally affected by a cylindrical cavity, in which a spacer <NUM> is preferably housed, which at the inner end is constrained to a plate <NUM>, housed inside the expansion chamber <NUM>, and at the external end it rests on a helical spring <NUM>, interposed between the spacer <NUM> itself and the bottom of the knob <NUM>.

The connection between the plate <NUM> and the spacer <NUM> is preferably obtained by means of a screw <NUM> and a nut <NUM>, or by means of a screw <NUM> engaging directly in a threaded portion formed in the spacer itself.

A graduated scale <NUM> is provided on the outer side wall of the sleeve <NUM>, showing indications corresponding to the pitch of the thread <NUM>, in order to establish a correlation between the degree of screwing of the knob <NUM> on the sleeve <NUM> and the indication highlighted by the edge of the knob itself on the graduated scale <NUM>.

Furthermore, in the circular edge of the knob <NUM> there are notches which divide the edge itself into equal portions, for example ten, so as to indicate on an index of the scale <NUM> the fraction of a turn of the knob itself.

In this way, the scale <NUM> bearing on the sleeve <NUM> and the scale on the edge <NUM> of the knob <NUM> allow to define in an objective manner the size of the screwing of the same knob on the sleeve <NUM> and consequently the degree of preload of the spring <NUM>.

Between the base <NUM> and the cover <NUM> the discoidal membrane <NUM> is interposed having an extension substantially identical to that of the base <NUM> and of the cover <NUM>. It is kept adherent to the upper surface of the base <NUM>, and therefore in a position to close both the hole <NUM> and the holes <NUM>, by the plate <NUM> pushed by the spring <NUM> through the spacer <NUM>. It is also provided that the membrane <NUM> and the plate <NUM> can be made in a single body, which in the central part is substantially rigid while in the annular peripheral part it is elastically yielding.

In any case, it is preferable that a toroidal gasket <NUM> is interposed between the elastic membrane <NUM> and the base <NUM>, which is partially housed within a circumferential groove <NUM> obtained in the base <NUM> and ensures the seal of the distribution chamber <NUM> when the cover <NUM> is fixed to this by means of screws <NUM>.

The operation of the dispensing device according to the invention is as follows: in the absence of flow of fluid from the pump into the tube <NUM>, the spring <NUM> presses, through the plate <NUM>, the membrane <NUM> against the upper surface of the base <NUM>, and keeps all the holes <NUM> closed, preventing the leakage and dripping of the fluid present in the circuit from the pipes <NUM>.

In the presence of fluid flow from the pump into the pipe <NUM>, the force exerted by the fluid on the membrane <NUM> causes the spring to compress <NUM> and lift both the membrane <NUM> and the plate <NUM>, creating the distribution chamber <NUM> which connects, in an open circuit, the tube <NUM> with the tubes <NUM>. The amount of fluid that flows depends on the pressure created by the pump in the tube <NUM> or on any nozzles with a calibrated hole inserted in the circuit of the tubes <NUM> or on another known regulation method.

When the flow of fluid from the pump into the pipe <NUM> is interrupted, the pressure previously present in the distribution chamber <NUM> decreases; in this way the thrust exerted by the spring <NUM> on the plate <NUM> and, consequently, on the membrane <NUM>, prevails and brings the membrane itself into contact with the upper surface of the base <NUM>, pressing it against this and causing the simultaneous closure of all the holes <NUM>.

It should be noted that the pressure which causes the detachment of the membrane <NUM> from the upper surface of the base <NUM> is defined by the force which is necessary to compress the spring <NUM> and which is adjustable by the operator by screwing / unscrewing the knob <NUM> and consequent variation of the preload spring <NUM>. This pressure is determined according to various variables such as in particular the width of the operating front of the machine, the working conditions, transport and use of the same, the flow rate of the fluid to be distributed, its viscosity or other characteristics, the number of ducts <NUM>, etc..

Moreover, it is also provided that as an alternative to the manual actuation of the knob <NUM>, this can be operated with an electric, pneumatic, hydraulic or similar mechanism, in itself known, which can be controlled automatically or manually by the operator sitting in his seat.

In order then to obtain a correct correspondence between the position of the index of the knob <NUM> and the pressure value of the fluid to cause the delivery and the cessation of the delivery of the fluid, that is to say in order to regulate the extent of the pre-charge of the spring <NUM>, further adjustment spacers <NUM> can be interposed between the spring itself and the spacer <NUM> or between the spring itself and the plate <NUM>.

The connections <NUM> can have the hole with a size such as to allow a copious flow of the fluid to be distributed on each delivery duct <NUM>, but they can also have a calibrated hole to accurately determine the quantity of fluid to be distributed on each delivery duct <NUM>. Alternatively, instead of the connections <NUM>, the holes <NUM> obtained in the base <NUM> can be calibrated. The operation of the device according to the invention is not affected by the presence or absence of calibrated holes <NUM> or calibrated connections <NUM>.

It is clear that the dispensing device according to the invention is much more advantageous than traditional devices and in particular:.

In a different embodiment, the device according to the invention has no spacer and has the spring <NUM> which presses directly on the plate <NUM>. In this case, however, it is advisable for the plate <NUM> to remain centered in the expansion chamber <NUM> and therefore with respect to the spring <NUM>, and this can for example be obtained by making a centering relief of the latter on the surface of the plate facing the spring.

In another embodiment, if the preloading conditions of the spring (i.e. of the opening pressure of the circuit) are known and constant, it is possible to simplify the device by making the blind sleeve <NUM> at the upper end and with a depth defined in in such a way as to obtain the desired preload of the spring <NUM>, which in this case is fixed and does not require the knob <NUM>. If, however, variations in the preload of the spring <NUM> are required, these can be obtained in a fixed way, that is not adjustable, by inserting or removing adjustment spacers <NUM>.

It is also provided that in order to make the closing action exerted by the membrane <NUM> on the holes <NUM> more effective, the membrane itself is made with its surface facing towards said holes affected by protuberances of various shapes (conical, truncated cone, hemispherical or similar) positioned in correspondence with these in order to close them more effectively.

Claim 1:
Device for dispensing fluid products, comprising a dispensing unit (<NUM>), to which a first duct (<NUM>) for the supply of said fluid to be dispensed leads, said dispensing unit (<NUM>) comprising a base (<NUM>), which includes a plurality of second ducts (<NUM>) for dispensing said fluid, and a cover (<NUM>), which defines with said base an expansion chamber (<NUM>) and a distribution chamber (<NUM>), in the which also opens said first duct (<NUM>) for the adduction of said fluid, the device further comprising:
- an elastic membrane (<NUM>) interposed between said base (<NUM>) and said cover (<NUM>) and having a first surface and a second surface , the latter facing all the outlet openings (<NUM>) of said second ducts (<NUM>) in said distribution chamber (<NUM>), characterized in that the device further comprises:
- a plate (<NUM>) arranged within said expansion chamber (<NUM>) and adhering to said first surface of said membrane (<NUM>), and
- elastic means (<NUM>) as associated with said plate (<NUM>) and configured to keep said membrane (<NUM>) elastically pressed against said openings (<NUM>) of said second ducts (<NUM>).