DEVICE FOR MIXING AGRICULTURAL COMPOUNDS

The present invention relates to a device for mixing agricultural compounds, meaning a device that can mix two or more products in such a way as to obtain an agricultural compound. The compounds mixed by the device according to the present invention may be, by way of example, fertilizers, plant protection products or the like. A similar device to that of the present invention may also be used to mix food products, pharmaceuticals, detergents or the like.

There are devices of the prior art for mixing agricultural products. Such devices comprise a tank in which the substances to be mixed are deposited, for example, water and a powdered plant protection product. A mixer is placed in the tank, so as to exert a mixing action that makes the mixture uniform. A dispensing conduit is connected in fluid communication with the tank. A hydraulic pump is placed in communication with the tank and with the conduit, so as to maintain a pre-established pressure within such conduit to promote the dispensing of the mixed compound, for example, on a cultivated field.

Disadvantageously, the need to mix the product within the tank constitutes a strong limitation to the use of devices of the prior art. It is, in fact, necessary to estimate the total quantity of product to be dispensed before mixing. Usually this quantity is a function of the dimensions of the field, the type of product, the mixing percentage and the type of crop. It is usual for such a quantity to be estimated in excess, therefore some mixed product remains in the tank after the spraying of the field. The remaining product must be stored according to special procedures, which prevent the dispersion of the product into the environment.

In this context, the technical task underpinning the present invention is to provide a device for mixing agricultural compounds which obviates the drawbacks of the prior art as cited above. In particular, the object of the present invention is to provide a device for mixing agricultural compounds which can mix a suitable but not excessive quantity of compound for the user requirements.

The set technical task and specified aims are substantially attained by a device for mixing agricultural compounds comprising the technical characteristics set out in one or more of the appended claims.

Further characteristics and advantages of the present invention will become clearer from the indicative, and therefore non-limiting, description of a preferred but not exclusive embodiment of a device for mixing agricultural compounds, as illustrated in the attached drawings, in which:

- Figure 1 is a front sectional view of a device for mixing agricultural compounds according to the present invention;

- Figure 2 is a lateral sectional view of the device of Figure 1 ; and

- Figure 3 is a block diagram representative of the operation of the device of Figures 1 and 2.

With reference to the attached figures, 1 indicates a device for mixing agricultural products according to the present invention. By way of example, the device 1 according to the present invention is able to mix a first and a second product so as to obtain a mixed agricultural compound. In particular, the first and the second product may be fluids (in the liquid or gaseous state), semi-fluids (for example a paste or a gel) or incoherent solids (for example powder or granules). Furthermore, the first and the second product may not be uniform, but in turn be a pre-established mixture of further products.

Finally, it should be noted that the device 1 according to the present invention may mix any number of products, if the type of specific application requires it.

The device 1 comprises an inlet conduit 2 of the mentioned first product which may be, by way of example, water or another solvent in liquid form. Furthermore the device 1 comprises an outlet conduit 3 of the mixed compound. Such outlet conduit 3 is placed in fluid communication with the inlet conduit 2.

Dispensing means may be connected to the outlet conduit 3, so as to directly use the mixed compound. Such dispensing means are not illustrated, since they are not part of the present invention.

In particular, the device 1 comprises at least one mixing chamber 4 associated with the inlet 2 and outlet 3 conduits. In particular, the mixing chamber 4 is switchable between a picking position and a mixing position. In detail, in the picking position the mixing chamber 4 is filled with a predetermined dose of the second product to be mixed with the mentioned first product. In other words, the mixing chamber 4 is placed in fluid communication with a source 5 of second product. Such second product may be, by way of example, a powdered fertilizer or a plant protection product for agricultural use.

In the mentioned mixing position, the mixing chamber 4 is placed in fluid communication with the inlet 2 and outlet 3 conduits, so as to effectively operate the mixing of the first and the second product, and obtain a mixed agricultural compound. In other words, the first product enters the mixing chamber 4 previously filled with the second product, becoming mixed with it and producing the mixed agricultural product. Such agricultural compound therefore flows through the already mentioned outlet conduit 3. The device 1 further comprises movement means 6 of the mixing chamber 7, which can move it at least between the picking and mixing positions with a frequency "f". Note that, given a flow rate of the first product that crosses the inlet conduit 2, the concentration of the second product in the mixed compound will be directly proportional to the frequency with which the mixing chamber 4 alternates between the picking and mixing positions.

With reference in particular to Figure 1 , the device 1 comprises a mixing organ 7 which has an axis of rotation "A". In particular, the mixing organ 7 is rotatable about the axis of rotation "A", and has a central zone 7a, proximal to the axis of rotation "A", and a peripheral, more external, zone 7b.

The mixing chamber 4 is in particular afforded in the peripheral zone 7b of the mixing organ. In this way, the rotation of the mixing organ 7 about the axis of rotation "A" performs the switching of the mixing chamber 4 between the mentioned picking and mixing positions. Note that on the mixing organ 7 a number of mixing chambers 4 can be afforded, preferably angularly equally spaced with respect to the axis of rotation "A". The movement means 6 comprise a motor 8 connected to the mixing organ 7 so as to make it rotate with a rotational speed (Vr) about the axis of rotation "A". In particular, the motor 8 is of the hydraulic type and, preferably, is regulated by a hydraulic circuit valve (neither shown in the attached figures). The opening of such valve corresponds to a proportional increase in the rotational speed (Vr). In an alternative embodiment of the invention, the motor 8 is an electric motor.

With particular reference to Figure 1 , the mixing organ 7 has a discoidal shape, and the axis of rotation "A" passes through its centre.

Note that the mixing organ 7 is arranged between two clamp discs 10, 12, which have the function of locking it within the device 1 and, simultaneously, allowing its rotation about an axis of rotation "A". In particular, the mixing organ 7 is in contact with such discs 10, 12.

In further detail, the device 1 comprises a support frame 9, inside which the mentioned inlet 2 and outlet 3 conduits are afforded. The discs 10, 12 are supported by the frame 9. As shown for example in Figure 1 , the discs 10, 12 are stacked up vertically and, in particular, are arranged coaxially between each other. In other words, the device 1 comprises an upper disc 0, and a lower disc 12, between which the mixing organ 7 is arranged. The movement means 6 comprise a shaft 13, arranged parallel to the axis of rotation "A". More particularly, the shaft 13 rotates about the axis of rotation "A". The mixing organ 7 is fitted onto such shaft 13, so as to be mixed in rotation by the motor 8 through the shaft 3.

In further detail, the discs 10, 12 have respective central zones 10a, 12a and peripheral zones 10b, 12b. As shown for example in Figure 1 , the central zones 10a, 12a each have a respective through hole 14. The shaft 13 is inserted in the holes 14. Note that the upper disc 10 and the lower one 12 are not fitted onto the shaft 13 and, consequently, the mixing organ 7 rotates with respect to them.

Note also that the upper disc 10 has a through opening 15, in particular at its own peripheral zone 10b. Such opening 15 is substantially placed at the same distance from the axis of rotation "A" of the mixing chamber 4. Consequently, with the rotation of the mixing organ 7, the mixing chamber 4 transits at such opening 15, in particular when it is in the picking position. The second product is in fact inserted into the mixing chamber 4 through such opening 15, in particular from a hopper 16 placed at the opening 15. The second product passes from the hopper 16 to the mixing chamber 4 by gravity, in particular until the complete filling of the mixing chamber 4.

The lower disc 12 has a further through opening 17, which is also placed substantially at the same distance from the axis of rotation "A" of the mixing chamber 4, but at a different angular position with respect to the opening 15 of the upper disc 10. In particular, the mixing chamber transits at the further opening 17 and enters into fluid communication therewith when it is in the mixing position.

The inlet conduit 2 is in fact oriented in the direction of the further opening 17, so as to direct towards it a flow of first product, in particular through a nozzle 18. When the mixing chamber 4 transits at the further opening 17, the flow of first product enters the mixing chamber 4 and becomes mixed with the first product. The resulting compound then passes out of the nozzle 18, and then flows into the outlet conduit 3.

Note that, following the passage at the further opening 17, the mixing chamber 4 still contains residues of first product and/or second product and/or mixed compound. In order to dispose of them, the mixing chamber 4 is switchable into a discharge position, wherein it is in fluid communication with the outlet conduit 3 and with a vent 19. In detail, the discharge conduit 20 is afforded within the lower disc 12 and placed in fluid communication with the outlet conduit 3. Furthermore, the discharge conduit 20 is placed substantially at the same distance from the axis of rotation "A" of the mixing chamber 4. The vent 19 is afforded on the upper disc 10, in particular in the same angular position as the discharge conduit 20. Consequently, when the mixing chamber 4 passes into the discharge position it enters into fluid communication with the vent 19 and with the discharge conduit 20. The mixing chamber 4 then pours its contents into the discharge conduit 20, and is emptied before passing into the picking position.

Note that, during the operating cycle of the device 1 , a presser organ 21 keeps the discs 10, 12 in close contact with the mixing organ 7, so as to prevent any leakage between them. Merely by way of example, such a presser organ 21 may be a spring, arranged coaxially with respect to the shaft 13. In addition or as an alternative to such a spring, the presser organ 21 may comprise a plurality of grips (not illustrated).

As shown for example in Figure 3, the device 1 comprises a sensor 22 associated with the inlet conduit 2. Such sensor 22 is configured to detect a signal "S1 " representative of a flow rate of first product in the inlet conduit 2. In particular, the sensor 22 is a flow meter. For example, the sensor 22 may be of the turbine, vane, nutating disc or electromagnetic type.

In greater detail, the device 1 comprises a processing unit 23 associated with the sensor 22 and with said movement means 6 of the mixing chamber 4.

In general, it should be noted that in the present context and in the subsequent claims, the processing unit 23 is presented as being split into distinct functional modules (storage modules or operative modules) for the sole purpose of describing its functionalities clearly and completely.

In actual fact, this processing unit 23 can comprise a single electronic device, appropriately programmed to perform the functionalities described, and the different modules can correspond to hardware entities and/or routine software that are part of the programmed device.

As an alternative or in addition, such functionalities can be performed by a plurality of electronic devices on which the aforementioned functional modules can be distributed.

The processing unit 23 can also make use of one or more processors for performing the instructions contained in the storage modules.

The aforementioned functional modules can, also, be distributed on different calculators locally or remotely based on the architecture of the network in which they reside.

The processing unit 23 comprises a reading module 24 configured to acquire a value "Q" of the mentioned signal "S1". In detail, the reading module 24 acquires such value "Q" in digital form. In an alternative embodiment, the value "Q" may be kept in analog form.

The processing unit 23 further comprises a control module 25 configured to obtain a target value "fO" of the switching frequency "f of the mixing chamber 4 as a function of the mentioned value "Q". In other words, the control module 25 is able, as a function of the value "Q" detected of the flow rate of first product within the inlet conduit 2, to calculate the corresponding frequency value "f" (i.e. the number of steps of the mixing chamber 4 in the unit of time) necessary in order for the mixing percentage between the first and the second product to be kept constant.

In particular, the control module 25 is configured to obtain the target value "fO" of frequency "f" in a directly proportional way to the value "Q". In yet further detail, the calculation module 25 is configured in order to calculate the target value "fO" by multiplying the value "Q" of the signal "S1" by a pre-established gain "G".

The processing unit 23 further comprises an operative module 26, configured to activate the movement means 6 and therefore to vary the frequency T as a function of the target value "fO". In particular, the operative module 26 is associated with the motor 8, and is able to increase and/or decrease the revolutions of the motor 8 as a function of the target value "fO" of frequency "f". In other words, the operative module 26 is configured to vary the rotational speed "Vr" of the motor 8 as a function of the target value "fO" of frequency "f".

In particular, the operative module 26 is configured to increase the frequency "f", in particular the revolutions of the motor 8, in the event that such frequency "f" is less than the target value "fO". Likewise, the operative module 26 is configured to reduce the frequency "f in the event that the frequency "f is higher than the target value "fO". In other words, the operative module 26 is configured to pursue the target value "fO".

In further detail, the operative module 26 is configured to send a control signal "U" to the motor 8. Such a control signal "U" is representative of a target rotational speed "VO" of the motor 8. Note that the target rotational speed "VO" is directly proportional to the target frequency "fO".

The processing unit 23 is further configured to calculate the mentioned gain "G" as a function of a pre-established parameter "c" to be inserted by a user. Such a parameter "c" is in particular representative of a mixing ratio between the first and the second product. Even more in particular, the processing unit 23 comprises an interface module "27" configured to enable a user to insert such a parameter "c". Merely by way of example, such interface module 27 may comprise a monitor or a keyboard, a knob or equivalent devices.

The present invention reaches the proposed object. Since the mixing is performed at the same time as the dispensing of the product mixed by the outlet conduit, only the amount of compound effectively needed is produced, avoiding the problems connected with excess mixing.

The present invention also provides important advantages. In fact, the processing unit is able to guarantee a suitable mix for varying the incoming amount of first product, guaranteeing the effectiveness of the mixing device in a wide interval of values of such flow rate. The user further has the possibility to select the mixing ratio and, once it has been selected, the device can keep it constant.