WO2021090346A1

WO2021090346A1 - Method to dispense fluid products

Info

Publication number: WO2021090346A1
Application number: PCT/IT2020/050259
Authority: WO
Inventors: Andrea ALVISI; Andrea Bergamini; Maurizio Meschiari
Original assignee: Corob S.P.A.
Priority date: 2019-11-08
Filing date: 2020-10-27
Publication date: 2021-05-14
Also published as: IT201900020608A1

Abstract

Method to dispense fluid products, which provides to receive, as input datum, a target formulation selected by an operator and comprising one or more fluid products, each to be delivered according to a predetermined quantity in order to obtain said target formulation, and corresponding machine (10) to dispense fluid products suitable to implement the dispensing method as above.

Description

“METHOD TO DISPENSE FLUID PRODUCTS”

FIELD OF THE INVENTION

Embodiments described here concern a method to dispense fluid products.

The method in question is intended to be implemented in an automatic or semi-automatic dispensing machine for fluid products, mainly for industrial use, in particular configured to dispense the product according to gravimetric techniques.

Such dispensing machines are suitable to dispense fluid products, for example fluid coloring products such as paints, impregnants, or fluid products for gluing, and others, which provide a final fluid product in a required target formulation, for example to obtain a defined shade of color, mixing base colors and pigments of the appropriate shades and in the appropriate quantities.

Embodiments described here also concern the dispensing machine suitable to implement the method as above.

BACKGROUND OF THE INVENTION

Dispensing machines of fluid products are known, mainly for industrial use, to dispense products such as for example paints, impregnants and others, to obtain a target formulation by mixing, for example, base colors and pigments of the appropriate shades and in the appropriate quantities.

Usually, known dispensing machines are based on techniques for measuring the quantity of fluid product of the volumetric, gravimetric type or a combination of both.

Dispensing machines based on volumetric techniques control the volume of the product delivered by controlling the volumetric pump configured to deliver it.

In dispensing machines based on gravimetric techniques, on the other hand, the weight of the product delivered is detected by means of gravimetric measuring devices for measuring the weight of the product, such as for example scales.

Furthermore, dispensing machines can function fully automatically or semi- automatically, where intervention by an operator is required to manage the different dispensing cycles.

The delivery of the fluid products must be precise, in order to provide one or more fluid products according to the predetermined proportions to obtain the required target formulation.

Generally, to obtain the required precision, correlation tables are used between the desired volumes and/or weights and a dispensing parameter, such as for example the number of steps performed by the motor of a delivery pump to dispense the desired volumes and/or weights as above.

To obtain a real evaluation of the fluid product dispensed, a feedback control is used which provides, for example, to measure the weight of the product dispensed. In a gravimetric machine, this is then correlated, by means of the specific weight of the product being dispensed, with the volume dispensed, and therefore with the respective steps of the motor of the volumetric pump.

Generally, in a calibration step, a control system communicates with the measuring devices and the dispensing machine in such a way as to receive, respectively, from the measuring devices the measurements of quantity of the fluid product dispensed and, from the dispensing machine, the values of the dispensing parameter that were needed to dispense it in order to obtain the correlation tables.

As well as being precise, the delivery operation must be fast, to guarantee adequate productivity for the dispensing machine.

Systems to dispense fluid products are described, for example, in U.S. Documents No. 2003/0121561 and 2005/0103700.

One disadvantage of dispensing machines and dispensing systems of a type known in the state of the art is that the quantity of product to be delivered significantly influences the precision and speed of delivery.

For example, when delivering small quantities, it may be necessary to use dedicated valve components for small quantities in order to reduce instrumental uncertainty, with an increase in the total dispensing time.

Otherwise, the instrumental uncertainty associated with the measurement of small quantities of fluid product is proportionally much greater, compared to the case in which larger quantities are delivered.

On the other hand, the delivery of large quantities of product makes it desirable to adopt a higher delivery speed, in order to allow a faster delivery process. In this case, in general, the precision of measurement of the quantity of product delivered may decrease, as the required quantity (and consequently the delivery speed) increases.

To obviate this problem, dispensing machines of the type known in the state of the art can use, during the same delivery operation, a higher speed in the first delivery step and then reduce it during the final step in order to obtain better precision.

One disadvantage of this solution is that the delivery times remain in any case very high, to the detriment of the productivity of the dispensing machine. In fact, it must be considered that the dispensing process may provide to wait for the feedback from the weighing instrument after each dispensing step, and possibly to refine the quantity of fluid dispensed by successive approximations.

There is therefore a need to perfect a dispensing method and a dispensing machine that implements said method, which are able to overcome at least one of the disadvantages of the state of the art.

One purpose of the present invention is to make available a method to control the functioning of a dispensing machine for fluid products that can allow the precise delivery of fluid products so as to obtain the required target formulation with great reliability.

It is also a purpose not to have to provide valve components dedicated to delivering small quantities of fluid product.

Another purpose is to reduce the number of successive approximations in order to approach the quantity of fluid product to be delivered with the desired precision without exceeding it.

Another purpose of the present invention is to provide a method that guarantees delivery times of the fluid product suitable to allow the dispensing machine to have high productivity.

Another purpose of the present invention is not to have to modify the delivery speed, providing a final delivery step at low speed in order to achieve the required precision, as instead usually happens when large quantities of product have to be dispensed.

One purpose is also to perfect a dispensing machine on which the dispensing method according to the present invention can be implemented.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the above purposes, the present invention concerns a method to dispense fluid products, which can be implemented on a machine to dispense such products.

According to some embodiments, the dispensing method can provide to receive, as input datum, a target formulation selected by an operator and comprising one or more fluid products, each to be delivered according to a predetermined quantity in order to obtain the target formulation.

Each fluid product making up the target formulation is then distributed in a dispensing cycle. The target formulation is obtained at the end of the dispensation of all the dispensing cycles of the fluid products provided for that formulation. In general, the dispensing cycles of fluid products can be provided one after the other.

The dispensing method, according to the invention, provides to divide each dispensing cycle of the fluid product into a plurality of dispensing sub-cycles (n), wherein the nominal dosage of product to be delivered in each sub-cycle is constant and equal to one nth-fraction of the total quantity of fluid product to be delivered, where n is the number of sub-cycles provided.

According to some embodiments, the dispensing method can provide to measure the quantity of product delivered during each sub-cycle.

According to some embodiments, the dispensing method can also provide to use the measured datum of the quantity of product delivered in order to correct in feedback the dosage error found in a previous sub-cycle, modifying the nominal dosage of the subsequent sub-cycle.

The correction of the dosage error can occur using the measurement datum of the quantity of fluid product delivered, implementing a feedback control cycle.

One advantage is therefore the fact that the method allows to achieve the desired accuracies for the delivery of the quantity provided of each fluid product required to prepare the target formulation.

One advantage is also that it is not necessary to use dedicated valve components, usually necessary for delivering small quantities of fluid product in order to achieve the desired accuracies.

Another advantage is reducing the number of successive approximations necessary to approach with the desired precision the quantity of fluid product to be delivered without exceeding it, since the dosage error is progressively reduced during the subsequent sub-cycles.

In fact, according to the invention, it is possible to reduce the element of uncertainty caused by the instrumental uncertainty typical of any delivery device which any delivery process is subject to, and caused by the fact that the first dosages of each fluid product are usually more critical and subject to greater dosage errors.

In the latter case, the causes of error in the delivery may be due, for example, to the resolution characteristics of the delivery means, or to the fact that a certain amount of time has passed since the last delivery of such fluid product, or to the fact that the delivery duct is partly blocked due to impurities, since the duct can be cleaned during use thanks to the pressure of the fluid delivered, or other similar causes.

Therefore, the dispensing method, by compensating for the previous dosage errors during the dosages of the subsequent sub-cycles, allows to reach the desired accuracies for the delivery of each fluid product in order to reach the target formulation.

According to some embodiments, the dispensing method can also provide to maintain the dispensing speed of the fluid product constant in all the sub-cycles, so that such speed is not correlated to the quantity of the fluid product to be delivered.

One advantage of the present invention is therefore that the dispensing speed is not modified within a same delivery cycle, therefore it is not necessary to provide a final delivery step at low speed in order to achieve the accuracy required.

By this we mean that the dispensing speed in steady state during the delivery process is maintained constant, where with the term steady we refer to the fact that the speed has reached its maximum value and therefore remains constant over time.

Since usually the delivery accuracy also varies as a function of the delivery speed, a constant delivery speed allows to improve the accuracy during the delivery of each fluid product.

It will therefore be easier for the composition of the final product to correspond to the required target formulation and/or be achieved in a shorter time.

One advantage is also that, by dividing the cycle into sub-cycles and correcting the delivery error, the total speed of the process to deliver the target formulation can be increased, compared to the methods used in the machines comprised in the state of the art, while maintaining the desired accuracy.

In accordance with the above purposes, the present invention also concerns a machine to dispense fluid products able to implement the method to dispense fluid products according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a perspective view of an embodiment of a machine to dispense fluid products suitable to implement the method according to the present invention;

- fig. 2 is a detailed perspective view of a dispensing unit and of a container for the fluid products delivered which is associated with a gravimetric device located on a support mean of the dispensing machine of fig. 1 ;

- fig. 3 is a graphic representation of the process to deliver the fluid product in an embodiment of the dispensing method according to the invention.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

We will now refer in detail to the possible embodiments of the invention, of which one or more examples are shown in the attached drawings. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, one or more characteristics shown or described insomuch as they are part of one embodiment can be varied or adopted on, or in association with, other embodiments to produce further embodiment. It is understood that the present invention shall include all such modifications and variants.

With reference to the attached drawings, a machine 10 to dispense fluid products is described, comprising a plurality of containing units 11 , at least one dispensing zone 12, at least one head 13 to dispense the fluid products, user interface means 14 and a programmable control unit 15.

According to some embodiments, the control unit 15, of the type known in the state of the art, can be configured as a processor or a microprocessor or other, capable of storing and processing data. The control unit 15 is able to comprise calculation algorithms to control the delivery process.

According to some embodiments, said calculation algorithms are able to implement a method to dispense fluid products according to the invention.

According to some embodiments, the user interface means 14 are able to allow the operator to select the formulation to be delivered and to control and display the delivery status, in accordance with the dispensing method according to the present invention.

The user interface means 14 can for example comprise displays, for example of the touch type, a mouse or keyboards or other types of interfaces, for example of the audio type.

According to some embodiments, the containing units 11 are each able to contain one respective fluid product to be delivered.

Each containing unit 11 can generally comprise a container 16 for the fluid product. The container 16 generally has an upper aperture, which can be closed by means of a lid 26, through which it is possible to introduce the fluid product into the container 16, and one or more exit apertures 17 which can be selectively closed by suitable valve means. The exit aperture 17 of the fluid product is connected to the dispensing head 13 by means of ducts 18.

The container 16 can also have a containing body 19 in which the fluid product is contained until the delivery. By way of example, the containing body 19 can have a volume from 100 ml up to 5 liters.

The dispensing machine 10 comprises dispensing means, of a known type and not shown, which are operatively associated with the containing units 11 in order to dispense a quantity of the fluid product contained therein. For example, the dispensing means can comprise pump units of a type known in the state of the art.

According to some embodiments, the head 13 to dispense the fluid products comprises a plurality of exit nozzles 20, each one connected to a respective container 16 by means of the ducts 18 as above.

Below the dispensing head 13 there is positioned the dispensing zone 12, in which one or more receptacles 21 are usually disposed, into which the fluid product can be delivered. The receptacles 21 can be open at the upper part and have a capacity suitable to contain the provided quantity of the desired formulation, for example they can be configured as tins or other containers, generally with a cylindrical or truncated-cone shape, such as a standard color can.

According to some embodiments, the dispensing head 13 can comprise a plurality of valves (not shown) configured to regulate and control the flow of the fluid products.

According to some embodiments, the dispensing zone 12 can have, in a known manner, support means 22 configured to receive, resting on them in a stable manner, the one or more receptacles 21 and/or one or more measuring devices 23 on which the one or more receptacles 21 can be located.

According to one embodiment, the support means 22 can comprise a ledge generally disposed in such a way that its support surface 24 is substantially parallel to the floor.

According to some embodiments, the dispensing machine 10 can also comprise and/or be interfaceable with gravimetric measuring devices 23.

Such measuring devices 23 are able to interface with the control unit 15, in order to supply the latter with the data relating to the quantity, or mass, of fluid delivered in each sub-cycle. In the example shown in figs. 1 and 2, the measuring devices comprise scales 23, as a non-limiting example of a measuring device suitable to measure the weight of the fluid product that has been delivered.

For example, the scales 23 can be digital scales, of a type known in the state of the art, having a resolution of 0.02 grams or better, for example 0.01 grams.

The scales 23 can comprise a support plane 25 on which the receptacle 21 can be received resting, into which the various fluid products are delivered in order to obtain the target formulation.

Some embodiments described here with particular reference to fig. 3 concern a method to dispense fluid products which can be implemented on a machine 10 to dispense fluid products.

According to some embodiments, the dispensing method provides to:

- receive, as input datum, a target formulation selected by an operator by means of the interface 14 and comprising one or more fluid products, each one to be delivered according to a predetermined quantity in order to obtain such target formulation;

- calculate, by means of algorithms which implement the dispensing method according to the invention, the dosages relating to each fluid product according to the proportions necessary to obtain the target formulation;

- dispense each fluid product necessary to obtain the target formulation, in the calculated proportions, for each corresponding dispensing cycle.

The dispensing method according to the invention provides to divide a dispensing cycle of each fluid product into a plurality of dispensing sub-cycles.

According to some embodiments, the nominal dosage of product to be delivered in each sub-cycle, according to the invention, can be constant and equal to one nth fraction of the total quantity of fluid product to be delivered, where n is the number of sub-cycles.

The number of sub-cycles n can for example be comprised between 2 and 10, providing a constant dosage for each sub-cycle comprised between half or a tenth of the total quantity to be delivered.

Preferably, the number of sub-cycles is equal to or greater than 3, and in particular equal to 3. In this way, a good compromise is generally obtained between the delivery speed of the fluid product and the delivery accuracy. In the example shown in fig. 3, three sub-cycles are provided, the nominal dosage to be delivered at the end of each sub-cycle being indicated by the values LI, L2 and L3. The graph, of the histogram type, has to be read cumulatively since in the second sub-cycle it is necessary to consider what has already been delivered in the first sub-cycle. From the theoretical point of view, in the second sub-cycle it is provided to deliver, as a nominal dosage, a quantity of fluid product equal to (L2-L1), while in the third sub-cycle a quantity of fluid product equal to (L3-L2).

According to some embodiments, the dispensing method can provide to measure the quantity of product delivered during each sub-cycle, by means of gravimetric measurements.

According to some embodiments, the dispensing method can provide to use the measurement datum of the quantity of product delivered in order to correct in feedback the dosage error found in a previous sub-cycle, modifying the nominal dosage of the subsequent sub-cycle.

In particular, during the dispensation of each fluid product necessary to obtain the target formulation, the correction of the dosage error for each corresponding dispensing cycle can provide the following steps:

- correlate the values of one or more operating parameters of dispensing means comprised in the dispensing machine 10, which are able to determine the dispensation of the quantity of fluid product with the quantity of fluid product to be delivered in each sub-cycle;

- deliver the nth- fraction of the total quantity of fluid product to be delivered;

- measure, in particular weigh, the quantity of fluid product delivered in the nth-fraction;

- calculate the dosage error that occurred in the sub-cycle as the difference between the theoretical quantity that was to be delivered and the quantity that has actually been delivered;

- determine an adjustment of the one or more operating parameters as above, on the basis of the previous step of correlation of the values of the one or more operating parameters, such adjustment having to be able to define, in the subsequent sub-cycle, the delivery of a quantity of fluid product different from the theoretical quantity as above, such as to compensate the dosage error as above, related to the previous sub-cycle, which has been calculated in the previous step;

- repeat the above described steps for each sub-cycle.

For example, if the measuring device 23 detects a weight of the product delivered in the first sub-cycle that is lower than the nominal dosage provided LI, then the control unit 15 will correct this error by modifying the operating parameters of the dispensing means so as to obtain an effective dosage of the fluid product in the second sub-cycle which is equal to a quantity equal to the difference between LI and the quantity measured by the measuring device 23. It is evident that if the measuring device 23 detects, instead, that the quantity dosed in the first sub-cycle exceeds the nominal value LI, then in the second sub-cycle it will be provided to modify the operating parameters of the dispensing means so as to obtain the delivery of a quantity smaller than the nominal quantity (L2-L1), by a value equal to the excess measured in the first sub-cycle. The method therefore provides to carry out the same feedback control of the quantity delivered in the second sub-cycle, in order to correct the quantity to be dispensed in the third sub-cycle, and so on, in the event a number of sub-cycles greater than three is provided.

For example, the operating parameter of the dispensing mean can be the number of revolutions of the motor that commands the volumetric pump comprised in the machine 10.

The steps of the method described above allow to obtain a “convergent” trend of the quantities of fluid product dispensed in each sub-cycle toward the nominal values that it is provided to dispense LI, (L2-L1) and (L3-L2). In other words, thanks to the steps of the method described above, it is possible to obtain a range of the band in which the effective dosage of fluid product for each sub-cycle can fall, which is decreasing from the first sub-cycle to the last sub-cycle.

This allows, for example, to reduce, from sub-cycle to sub-cycle, the extent of the error between nominal and actual dosage, allowing to adequately compensate for the initial error. As shown by way of example in fig. 3, the band in which the actual dosage of fluid product can fall can be distributed symmetrically with respect to the nominal dosage of each sub-cycle, having the same range both by excess, and also by defect. According to some embodiments and advantageously, only in the last sub cycle is the band in which the actual dosage of fluid product can fall such as to have only a negative band with respect to the nominal dosage, so as not to exceed the total quantity of fluid product to be delivered. For example, this can allow to correct, in a subsequent step not described in the present invention, a possible error in the formulation obtained.

According to some embodiments, the dispensing method can provide that, within a dispensing process of a target formulation, the dispensing speed of the fluid product in all the sub-cycles is independent of the total quantity of product to be delivered.

For example, even if a determinate target formulation consists of some fluid products in very different proportions with respect to each other, the delivery speed of the individual sub-cycles is maintained constant, thus maintaining the same precision regardless of the dosage of the fluid product. It is clear that modifications and/or additions of parts or steps may be made to the machine 10 to dispense fluid products and to the corresponding dispensing method as described heretofore, without departing from the field and scope of the present invention.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of dispensing machine 10 and corresponding method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

In the following claims, the sole purpose of the references in brackets is to facilitate reading: they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.

Claims

1. Method to dispense fluid products, which provides to receive, as input datum, a target formulation selected by an operator and comprising one or more fluid products, each to be delivered according to a predetermined quantity in order to obtain said target formulation, said dispensing method being characterized in that it provides to divide a dispensing cycle of each fluid product into a plurality of dispensing sub-cycles (n), wherein the nominal dosage of product to be delivered in each sub-cycle is constant and equal to one nth-fraction of the total quantity of fluid product to be delivered, where n is the number of sub-cycles provided.

2. Dispensing method as in any claim hereinbefore, characterized in that it provides to measure the quantity of product delivered during each sub-cycle, by means of gravimetric measurements.

3. Dispensing method as in any claim hereinbefore, characterized in that it provides to use the measured datum of the quantity of product delivered in one sub-cycle in order to correct in feedback the dosage error found in a previous sub-cycle, modifying the nominal dosage of the subsequent sub-cycle.

4. Dispensing method as in any claim hereinbefore, characterized in that it provides the following steps:

- to correlate the values of one or more operating parameters of dispensing means able to determine the dispensation of the quantity of fluid product with the quantity of fluid product to be delivered in each sub-cycle;

- to deliver the nth- fraction of the total quantity of fluid product to be delivered;

- to measure, in particular to weigh, the quantity of fluid product delivered in the nth-fraction;

- to calculate the dosage error that occurred in the sub-cycle as the difference between the theoretical quantity, that is, the nominal dosage, that was to be delivered and the actually delivered quantity;

- to determine an adjustment of said one or more operating parameters on the basis of the previous step of correlation of the values of the one or more operating parameters, said adjustment being able to determine, in the subsequent sub-cycle, the delivery of a quantity of fluid product different from said nominal dosage so as to compensate for said dosage error, related to the previous sub- cycle, which was calculated in the previous step;

- to repeat the above described steps for each sub-cycle.

5. Dispensing method as in any claim hereinbefore, characterized in that it provides to define a band where the actual dosage of fluid product can fall, said band being associated with the nominal dosage of each sub-cycle.

6. Dispensing method as in claim 5, characterized in that the range of said band is decreasing from the first sub-cycle to the last sub-cycle.

7. Dispensing method as in claim 5 or 6, characterized in that said band is distributed symmetrically with respect to the nominal dosage of each sub-cycle, with the exception of the last sub-cycle, having the same range both by excess, and also by defect; wherein in said last sub-cycle said band extends only below the nominal dosage.

8. Dispensing method as in any claim hereinbefore, characterized in that, within a dispensing process of a target formulation, it is provided to maintain the dispensing speed of the fluid product constant in all the sub-cycles, so that the speed is not correlated to the quantity of the fluid product to be delivered.

9. Machine to dispense fluid products, comprising a plurality of containing units (11), each containing a respective fluid product, at least one dispensing zone (12) in which it is provided to position, selectively and temporarily, one or more receptacles (21) for the fluid products to be delivered in a dispensing cycle, at least one head (13) to dispense the fluid products, user interface means (14) configured to allow an operator to select the target formulation to be delivered and to control and display the state of delivery and a programmable control unit (15), said dispensing machine being characterized in that the control unit (15) is programmed so as to allow the dispensing machine to implement a method to dispense fluid products as in any claim hereinbefore.

10. Machine to dispense fluid products as in claim 9, also comprising and/or being interfaceable with measuring devices (23) of the gravimetric type, characterized in that said measuring devices (23) are able to interface with said control unit (15) in order to communicate to the latter information about the detected mass of fluid product that has been delivered in each sub-cycle.