WO2003082452A1

WO2003082452A1 - Equipment for the metered dispensing of a fluid product, in particular a colouring agent for paints

Info

Publication number: WO2003082452A1
Application number: PCT/IB2003/001211
Authority: WO
Inventors: Antonio Martinelli; Rodolfo Reggiani
Original assignee: Cps Color Equipment S.P.A.
Priority date: 2002-03-28
Filing date: 2003-03-26
Publication date: 2003-10-09
Also published as: AU2003215831A1; ITBO20020162A0; ITBO20020162A1; WO2003082452A8

Abstract

This invention relates to equipment (1) for the metered dispensing of a fluid product, in particular coloring agent, comprising a single tank (10) for the coloring agent from which lead dispensing circuits (20a, 20b) .The dispensing circuits are fed by pumping means (22a, 22b) controlled by a common motor (50) .When the equipment is in operation the intercepting means (24a, 24b) are selectively activated according to the total quantity of coloring agent which has to be dispensed over a preset period of time.

Description

EQUIPMENT FOR THE METERED DISPENSING OF A FLUID PRODUCT, IN PARTICULAR A COLOURING AGENT FOR PAINTS

This invention relates to equipment for the metered dispensing of a fluid product, in particular a colouring agent for paints, and a dispensing process using such equipment. The invention has been developed with particular but not exclusive regard to equipment which can be incorporated into industrial plant for the manufacture of paints, varnishes, enamels, inks and fluid products in general .

Equipment of the type indicated above is generally used in the context of industrial plants for the preparation of coloured paints. As is well known, a very great variety of colour shades can be obtained by adding small doses of one or more concentrated colouring agents to a base product, generally of a white or neutral colour, in accordance with predetermined formulations . The quantity of colouring agent which has to be dispensed is generally a very small fraction of the quantity of the base product and paint as a whole, as a result of which the accuracy required when metering colouring agents must be high in order to obtain the precise colour shade desired, at least for each container in a given production batch. Equipment for the dispensing of colouring agents must therefore be designed to ensure high volumetric accuracy when metering colouring agents, partly in view of the small volumetric quantities which in general have to be dispensed.

However, in the context of the industrial manufacture of coloured paints, in some cases one or more colouring agents, known as "high turnover" agents, are used in larger quantities than others, for example because a large number of batches of paint require a particular preferential colour shade. In order to avoid slowdowns in the paint manufacturing chain it is customary to provide equipment for the dispensing of high turnover colouring agents with larger pumps than those used for the other colouring agents. This arrangement does however restrict the flexibility of the plants, because it is difficult to obtain good accuracy when it is desired to produce particular batches of paints whose formulations require that the high turnover colouring agents be delivered in small percentages, similar to those for other colouring agents.

The certainty with which the precise colour desired is reproduced is linked essentially to the accuracy of the volumes of concentrated colouring agent which are included in the paint composition. As already mentioned, the shade is the result of the combination of a base product with one or more colouring agents according to a predetermined formula. Because of the concentrated nature of these colouring agents even a very small error in their metering can give rise to a result which places it in a different position on the colour scale than that desired. It is therefore clear that the requirement for accuracy when dispensing volumes of colouring agent is equally great for both large and small quantities .

The purpose of this invention is to provide equipment for the metered dispensing of a fluid product, in particular a colouring agent for paints, which overcomes the above- mentioned disadvantages, and in particular can ensure high accuracy when dispensing either small or large quantities of fluid product, ensuring appropriate dispensing times which are satisfactorily short in relation to the quantity of fluid product which has to be dispensed, in particular making it possible for dispensing to take place at relatively high speed when the quantity of fluid product which has to be dispensed is correspondingly high.

Another object of the invention is to provide equipment which is simple and economical to manufacture, of small dimensions, and which is highly reliable when in use without particular attention being necessary for maintenance.

In order to accomplish the above-mentioned purposes the invention relates to an equipment for the metered dispensing of a colouring agent product for paints, characterised in that it comprises, in a working combination:

- a single tank for the colouring agent which is to be dispensed,

- at least two dispensing circuits for the colouring agent, communicating with the single tank, pumping means feeding the at least two dispensing circuits, intercepting means located in each dispensing circuit, downstream from the pump means and selectively activatable to deliver the fluid product to a corresponding dispensing pipe, and

- actuator means to control the pumping means, comprising a single motor operatively connected to the pumping means .

The invention also relates to a process for the metered dispensing of a fluid product through equipment of the above-mentioned type, characterised in that it comprises the stages of: establishing a predetermined quantity of the liquid product which is to be dispensed, and selectively activating the interception means for a predetermined time so as to dispense the said predetermined quantity of fluid product through only one of the at least two dispensing circuits.

The pumping means according to this invention may comprise a single pumping unit which feeds the at least two dispensing circuits, or separate pumps for each dispensing circuit.

According to an advantageous feature of this invention an encoder or other control means which are capable of detecting operating characteristics, including preferably speed, associated with the single motor or the motor means which drive the pump means may be provided. The system may make use of the information so obtained to check the accuracy of the volume of colouring agent dispensed, and/or establish the method of operation in order to dispense the desired dose . Preferably the information from the control means is considered in association with other information relating to the system, such as for example, but not restricted thereto, characteristic parameters of the components of the equipment. In a preferred embodiment the pumping means are rotatory metering pumps. Those skilled in the art may however use any system which is capable of performing the same functions .

In accordance with another advantageous feature it is possible to provide that the single motor, the pumps and any other components forming part of the equipment in question which are operationally connected together are housed on a support in such a way as to constitute a modular unit which can be easily inserted within more complex systems, and which is easy to remove and fit for any repairs or replacements .

Another advantageous feature of the invention is that it provides a control system capable of selectively determining the use of one of the at least two dispensing circuits on the basis of a comparison between the volume dispensed and the consequent efficiency.

In accordance with another feature of the invention product recirculation devices may be housed between the pumps and the interception means to allow maintenance and/or cleaning of the last length of the dispensing circuit .

In accordance with a further feature of the invention all the pumps may at all times remain operatively driven by the single motor providing interception means which prevent dispensing to the container intended to receive the product, associated with recirculation means of the known type.

Other advantages and characteristics of the present invention will become clear from the following detailed description which is given with reference to the appended drawings which are provided purely by way of non-limiting example and in which:

- Figure 1 is a functional diagram of a system for the dispensing of fluid products according to this invention,

Figure 2 is a front elevation view of a detail of equipment for the dispensing of fluid products according to this invention,

- Figure 3 is a view along the arrow III in Figure 2, and Figure 4 is a diagram showing accuracy values and dispensing times which are characteristic of the system to which this invention relates as a function of the volumes which have to be dispensed.

With reference now to Figure 1, equipment 1 for the metered dispensing of fluid products comprises a tank 10 in which a colouring agent product is stored while waiting to be dispensed. Preferably two dispensing circuits 20a and 20b having a low and a high dispensing capacity respectively leave tank 10. Low capacity circuit 20a comprises a colouring agent feed pipe 21a which is connected at the end opposite to that at which it is connected to tank 10 to a smaller pump 22a, preferably a metering pump, and in particular, although not exclusively, of the rotary type. From smaller pump 22a there leads a delivery pipe 23a at the end of which there is a first intercepting member 24a, preferably a 3 -way, two-position valve. From intercepting member 24a a dispensing pipe 26a empties out into a dispensing zone 27 in which a container 30 positioned to receive the components of the paint which is to be manufactured can be placed. A recirculation pipe 25a which communicates with tank 10 so as to return the colouring agent there when intercepting member 24a interrupts the flow of colouring agent towards dispensing zone 27 also leads from intercepting member 24a.

In turn high capacity circuit 20b comprises a pipe 21b feeding colouring agent from tank 10 to a larger pump 22b. A delivery pipe 23b leaves larger pump 22b and has an intercepting member 24b at its end opposite larger pump 22b. Dispensing pipe 26b and a recirculation pipe 25b leave intercepting member 24b, and these, as indicated above in the case of low capacity circuit 20a, are designed to carry the colouring agent to container 30 or tank 10 respectively. Intercepting members 24a, 24b have the function of enabling recirculation pipes 25a, 25b to transport colouring agent, shutting off dispensing pipes 26a, 26b or vice versa. Specifically the low and high capacity circuits 20a and 20b consist of similar functional members which in particular differ from each other from the point of view of dimensional characteristics .

A central motor 50 controls both smaller and larger pumps 22a and 22b through transmissions 52 and 54. A device to detect the speed of motor 56, preferably an encoder, is mounted on motor 50. Detection device 56 is operatively connected to a control member 60 which receives the signals from it indicating the speed of motor 50, and may possibly process them, together with other parameters which are characteristic of the operation of the system, and thus choose which of the two low and high capacity circuits 20a and 20b to use to dispense the quantity of colouring agent required. Control member 60 may control intercepting members 24a and 24b through communication circuits 62 and 63 respectively so that one of the two causes the colouring agent to be directed towards container 30 and the other directs it to recirculation. Control member 60 may also control the rotation of motor 50 through communication circuits 64 so as to obtain dispensing of the precise dose desired, or to keep the speed of the motor constant within preset limits.

With reference now to Figures 2 and 3, motor 50, preferably of the electrical type, controlled for example by an inverter, is mounted on a supporting plane 70 housed in a frame 110 which encloses within itself modular equipment 65. Motor 50 is connected to a reduction gearbox 72 from which pass two transmission shafts 74 and 76 operatively connected to corresponding universal joints 78 and 80. The universal joints are in turn operatively connected to corresponding drive shafts 82 and 84 of the pumps of smaller size 22a and larger size 22b. Smaller pump 22a has an inlet opening 86 to which feed pipe 21 communicating with tank 10 is connected. Similarly larger pump 22b has an inlet opening 88 which is connected to feed pipe 21a, which itself, as described above, communicates with the same tank 10. Smaller pump 22a also has an outlet opening 90 to which delivery pipe 23a is connected. Similarly larger pump 22b has an outlet opening 92 to which delivery pipe 23b is connected. The connections between pipes 21a, 21b and corresponding pumps 22a, 22b are constructed using components of a known and standard type and will not therefore be further described in this description. At the outlet from reduction gearbox 72 there is provided a fast rotation shaft 94 which is directly connected to the drive shaft of motor 50. Encoder 56 is preferably mounted on fast shaft 94. In another preferred embodiment encoder 56 may be mounted directly on the drive shaft of motor 50. At the ends of feed pipes 21a, 21b and delivery pipes 23a, 23b are mounted a number of taps 96, 98, 100, 102 to isolate the equipment from the rest of the circuit in which it is included in order, for example, to permit easy replacement or rapid maintenance .

With reference now to Figure 4, a possible process for use of the device characterised by a preferred method of selecting the dispensing circuit which is to be used is illustrated. Curve CVA represents the hypothetical change in the delivery error, otherwise known as the accuracy, of a circuit of a type similar to low capacity circuit 20a in relation to the volume of material which has to be dispensed. Curve CVB indicates the change in the same parameter for a circuit similar to high capacity circuit 20b. Curves CVC and CVD indicate the time difference required to dispense the volume of colouring agent through smaller pump 22a and larger pump 22b respectively. All the curves and relationships indicated are purely diagrammatical and are to be considered purely as examples. Some facts which are of general validity can however be observed. Drawing a line LLl corresponding to a desired accuracy value, for example but not restricted to 1%, the accuracy curve for the smaller pump CVA lies below that value only for dispensed volumes greater than a certain minimum value VI. This means that using smaller pump 22a it is not possible to ensure an accuracy of 1% for values of volumes which have to be dispensed which are less than the minimum value VI . In the case of higher values on the other hand the accuracy is always better, and are seen to lie around an asymptotic value less than 1%. The time curve for the smaller pump CVC indicates however that the time required for dispensing is very high in the case of large volumes. Where it is necessary to dispense a volume of colouring agent which is equal to or greater than an intermediate value V2 it becomes convenient to use high capacity circuit 20b because the accuracy curve for the larger pump CVB indicates that the accuracy of the high capacity circuit 20b is less than the value 1% in this zone, and at the same time the time curve for the larger pump CVD indicates that, for the same volume of colouring agent which has to be dispensed, the required dispensing time is less than that which would be necessary using low capacity circuit 20a. Equipment 1 thus has a maximum optimum operating limit V3 which is very much greater than a conventional device having a single dispensing circuit. From what has been described it follows that preferably within the volume range lying between the minimum value VI and the intermediate value V2 , indicated by PA, dispensing will take place via the low capacity circuit 20a while high capacity circuit 20b will be recirculated. Conversely, in the range between intermediate volume value V2 and the maximum limit value V3 , indicated by PB, high capacity circuit 20b will be used for dispensing while low capacity circuit 20a will be recirculated.

In accordance with this embodiment it is also possible to envisage simultaneous dispensing from the two high and low capacity circuits 20b and 20a, given that the smaller and larger pumps 22a and 22b are always in operation and that intercepting means 24a, 24b can be controlled in such a way as to place tank 10 in communication with dispensing pipes 26a, 26b simultaneously, rather than alternately, selectively depending upon the values set by control member 60 and the nature of the formulation of the colouring agent which has to be dispensed. This makes it possible to extend the dispensing capacity performance of equipment 1 to even very large volumes, greater than the maximum limit V3 previously considered, in short times and with an accuracy which is unchanged in comparison with dispensing performed by the individual smaller and larger pumps 22a and 22b through corresponding dispensing pipes 26a, 26b. In accordance with a variant of the invention it is possible to construct equipment with two or more absolutely identical circuits, with pumps of equal size, bringing about the dispensing of volumes larger than the optimum capacity of an individual pump merely by using the whole of equipment 1 or part thereof as a pumping unit in accordance with the methods of operation described above.

Although equipment 1 illustrated in the figures comprises only two low and high capacity circuits 20a and 20b, it is however possible to extend the innovative concept to any number of circuits, including those of an intermediate capacity, having functional characteristics which are similar to those described above .

Naturally, the principle of the invention remaining the same, the forms of embodiment and details of construction may be varied widely with respect to those described and illustrated, which have been given purely by way of example, without thereby departing from the scope of the invention.

Claims

1. Equipment for the metered dispensing of a colouring agent product for paints characterised in that it comprises, in an operating combination: a single tank (10) for the colouring agent to be dispensed, at least two dispensing circuits (20a, 20b) for the colouring agent, communicating with the single tank (10), pumping means (22a, 22b) feeding the at least two dispensing circuits (20a, 20b) ,

- interception means (24a, 24b) located on each dispensing circuit (20a, 20b) downstream of the pumping means (22a, 22b) and selectively activatable to deliver the fluid product to a corresponding dispensing pipe (23a, 23b) , and

- actuator means to control the pumping means (22a, 22b) , comprising a single motor (50) operatively connected to the pumping means (22a, 22b) .

2. Equipment according to Claim 1, characterised in that it comprises at least two pumping means (22a, 22b) , each mounted in a corresponding delivery circuit (20a, 20b) of the said at least two delivery circuits.

3. Equipment according to Claim 2, characterised in that it comprises means (56) to control the speed of the single motor (50) .

4. Equipment according to Claim 2, characterised in that the pumping means comprise at least two metering pumps of different size, each mounted in a corresponding dispensing circuit .

5. Equipment according to Claim 4, characterised in that the at least two metering pumps of different size are set to show an error which is equal to or less than a preset value, preferably equal to 1%, in the total volume of colouring agent transferred, on the basis of a minimum preset volumetric quantity of colouring agent transferred.

6. Equipment according to Claim 4 or 5, characterised in that the metering pumps are of the rotatory geared type.

7. Process for the metered dispensing of a fluid product, in particular colouring agent, using equipment according to any one of the preceding claims, characterised in that it comprises the stages of :

- establishing a quantity of colouring agent which has to be dispensed,

- activating the actuator means (50) for the pumping means (22a, 22b) , and

- selectively activating the intercepting means (24a, 24b) in relation to the total quantity of colouring agent which has to be dispensed over a preset period of time.

8. Process according to Claim 7, characterised in that selective activation of the intercepting means (24a, 24b) brings about dispensing of the said quantity of colouring agent through only one of the at least two dispensing circuits (23a, 23b) .