WO2004037400A2

WO2004037400A2 - A mixer for fluid products and mixing method

Info

Publication number: WO2004037400A2
Application number: PCT/IB2003/004719
Authority: WO
Inventors: Emanuele Morselli; Francesco De Bastiani; Giuliano Solera
Original assignee: Cps Color Equipment S.P.A.
Priority date: 2002-10-23
Filing date: 2003-10-22
Publication date: 2004-05-06
Also published as: WO2004037400A3; AU2003283614A1; ITBO20020671A1; EP1554034A2; BR0306619A; AU2003283614A8; ITBO20020671A0

Abstract

A mixer for fluid products, such as paints and varnishes, colouring agents and the like, comprises a main base (12), a support member (16, 42) coupled to the main base (12) on which to position at least one container (18) of fluid products, actuator members for moving the support member (16) with respect to the main base (12), and control means (20) for controlling the actuator members (14) in order to impart to the latter a selective mixing motion. The actuator members (14) are operable independently of one another by the control means (20) according to a predetermined drive sequence or law.

Description

A MIXER FOR FLUID PRODUCTS AND MIXING METHOD

The present invention refers to a mixer for fluid products, such as paints and varnishes, colouring agents and the like, comprising a main base, a support member for at least one container of fluid products, movement means for moving the support member with respect to the main base, and control means for the movement means to impart a selective mixing motion thereto. The present invention also relates to a method for mixing by means of a mixer of the a oresaid type .

It is known that each type of fluid product, and in particular paints and varnishes and colouring agents, require a personalised mixing cycle based on the physical and chemical characteristics. The mixers commercially available utilise mixing principles which render them particularly suited, if not actually dedicated, to a single product or to products having characteristics very similar to one another. For this reason, many types of mixers have been designed such as, for example, vibratory, gyroscopic or rotatory mixers. The paint-producing firms often recommend the mixer which, among these, provides the best results if used with their type of product. As a consequence of this "specialisation", the user who acquires a mixer today is tied to the choice of using always the same type or the same make of product, or of acquiring as many different mixers as there are types or makes that he intends to treat .

It is an aim of the present invention to solve the problems of the prior art, and in particular to provide a mixer usable in association with any type of fluid to be mixed, and to provide a method for using such a mixer which produces an optimum mixing quality for each type of product mixed.

It is also an aim of the present invention to provide a method for controlling and detecting the mixing quality obtained with a mixing process . A further aim of the present invention is to produce a mixer which is economic to produce, easy to use, very reliable, and easily and rapidly adaptable to changing work requirements.

In order to achieve the aims indicated, the subject of the present invention is a mixer of the type indicated in the preamble of the present description, in which the movement means comprise actuator members coupled to the support member and operable independently of one another by the control means according to a predetermined drive sequence or law.

The mixer according to the present invention lends itself to numerous variants.

One of the principal advantages obtainable with a mixer of this type is the possibility of producing, depending on the configuration of the control means, simple mixing motions, that is, derived from the sequential actuation of each single actuator member, or compound mixing motions, that is, derived from the sum of simple motions. Owing to the peculiarity of the independent control of each actuator member which produces the simple motions, the compound motions possible are in practice infinite. In fact, it is possible to control the actuator members according to drive sequences which produce simple motions or additions, prearranged successions and/or superpositions of simple motions. The mixer in question, therefore, offers the possibility of obtaining any personalised mixing cycle, and of applying the mixing cycle required by any type of product intended to be mixed.

According to an embodiment of the present invention, the main base comprises a fixed part, for example a plate resting on the ground, and a movable part, for example a second plate superposed on the fixed part and connected thereto by shock absorbers, such as springs and dampers, the support member being coupled to the movable part. In this way it is possible to absorb the vibrations produced by the different drive sequences applied to the mixer.

According to a further embodiment of the invention, the mixer comprises a guide coupled to the support member in order to limit the movement thereof in use. The guide comprises, for example, a first body, such as a hollow cylinder rigidly connected to the main base in a vertical position, and a second body, for example a second cylinder, telescopically slidable inside the hollow cylinder and connected to the central position of the support member by means of a ball- and-socket joint.

According to a preferred embodiment, the movement means comprise at least three linear actuators operated independently by the control means. For example, but not by way of limitation, it is possible to have three hydraulic or pneumatic jacks, the movement of which is controlled via solenoid valves or groups of solenoid valves, for example housed on the main base. The linear actuators have the advantage of having simple motions with a predetermined and controllable direction, thereby making it easy to forecast the motion resulting from a combination of simple motions.

According to an additional characteristic, each of the linear actuators is coupled to the main base and to the support member by means of ball-and-socket joints. In this way, there is the advantage of being able to select from more than one drive sequence by which to send the commands to the linear actuators in order to obtain the same predetermined movement of the support member. It is possible to limit the movement of the linear actuators to a predetermined work zone. The actuators may also be coupled to the main base by means of revolute pairs and to the support member by means of ball-and-socket joints, or vice versa. According to another additional characteristic, the support member for at least one container of fluid products is movable with respect to the main base, independently of the motion of the actuators. For example, the support member may be mounted so as to rotate and/or swing, so as to impart a further mixing motion to the fluid in the container, preferably superposed on the motion imparted by the linear actuators.

In a preferred embodiment, the mixer comprises a control system for transmitting commands to the actuator members through the control means . According to a preferred variant , the control system comprises an electronic processor which controls the control means and imparts to them the instructions necessary for sending the commands to the actuator means according to any predetermined drive sequence . In this latter case, it is not necessary to modify the configuration of the mixer to execute different sequences.

According to another particularly advantageous embodiment, the mixer comprises damping means coupled to the main base and/or to the support member to absorb, in use, at least part of the forces of inertia generated by the action of the movement means on the support member. Such damping means comprise, for example, a damping mass connected to the main base or to the support member by resilient means. In a preferred variant, a second damping mass may be connected to the first by second resilient means.

A particularly advantageous method for mixing fluid products by means of a mixer according to the present invention, comprising the steps of placing a container of fluid products on the support member of the mixer, actuating the control means to operate, for a predetermined period, the actuator members coupled to the support member, according to a drive sequence or law comprising a plurality of independent commands, sent by the control means to each actuator member. Finally, the control means are deactivated at the end of the predetermined period.

In a preferred variant, the mixing method comprises the steps of arranging a control system for controlling the actuation of the actuator members through the control means and actuating the actuator members in a predetermined sequence by means of the control system. The advantage of such a mixing method derives from the possibility of creating drive sequences associated with each fluid product to be mixed. Such sequences may, for example, be contained in an information technology support in the form of a processor program to be inserted in the control system of the mixer. In this way, the final user, rather than having a mixer dedicated to each type of product treated, may have only one, adaptable to the product.

The versatility of a mixer according to the present invention has been used by the Applicant to develop and perfect personalised drive sequences which have made it possible to study the effects of mixing on different samples of fluid products, in particular paints and the like. To this end, a very advantageous method has been developed for testing and verifying the mixing quality obtained, also applicable in a general way, however, to mixers of a different type. The method of verification provides for freezing the container with the mixed fluid immediately at the end of the mixing cycle. The frozen fluid may then be dissected and/or broken up in order to detect and study the effective degree of mixing achieved in every part of its volume.

Further characteristics and advantages will become clear from the following detailed description, with reference to the drawings, provided purely by way of non-limiting example, in which: Figure 1 is a diagrammatic front view of a mixer according to the present invention;

Figure 2 is an axonometric view of a mixer according to a preferred embodiment;

Figure 3 is a front view of a jack coupled to the base of a mixer in which the possible movements of the jack are represented;

Figure 4 shows the planes of action of 3 jacks coupled to the base of a mixer as in Figure 3 ;

Figure 5 is a diagrammatic front view of a mixer with a base comprising a suspension system;

Figure 6 is a diagram of the pneumatic control circuit of the 3 j acks of Figure 1 ;

Figure 7 is a drive sequence for the three jacks of Figure 1 ;

Figure 8 is a second drive sequence for the three jacks of Figure 1 ;

Figure 9 is a front view, partially in section, of a mixer comprising a guide system for the jacks;

Figure 10 is a plan view of a guide for the jacks of the mixer of Figure 9 ;

Figure 11 is a front view, partially in section, of a mixer with a dynamic damper appended to the support member;

Figure 12 is a front view of a damping system for damping the forces of inertia at two swinging bodies coupled to a mixer; Figure 13 is a front view of a damping system for damping the forces of inertia at one swinging body coupled to a mixer;

Figure 14 is a front view of a support member for containing a container of fluid;

Figure 15 is a front view of a support member for clamping a container of fluid; and

Figure 16 is a front view of a variant of the mixer of Figure 5, in which the base has two superposed damping systems.

With reference now to Figure 1, a mixer 10 comprises a base 12, onto which are hinged at one of their ends, preferably, but not by way of limitation, three actuators 14 which at the opposite end are hinged to a plate 16 which, in use, supports a container 18 of fluid to be mixed. A control unit 20 for controlling the actuators 14 is mounted, preferably, on the base 12 and is connected, by means of channels 22 for carrying signals, to a control system 24.

The base 12 comprises a fixed plate 26, ballasted by ballast means 28, and resting on the ground by means of feet 30, fixed to its lower face. A second plate 32 is fixed above to the fixed plate 26 by means of rigid supports 34 and has, on the upper face, three hinges 36, for example of the ball-and- socket joint or revolute pair type, each connected to one end of the three actuators 14.

The actuators 14 are preferably, but not by way of limitation, of the linear type, such as, for example, hydraulic jacks, electric motors coupled to nut screw devices, or, as will be assumed hereinafter solely by way of example, pneumatic jacks. Figures 3 and 4 illustrate the case where the jacks 14 are connected to the second plate 32 all by means of hinges 36 of the revolute pair type. In particular, in Figure 3 the arrows α, β and τ represent the movements of extension and rotation about the hinges 36 of the jacks 14. According to such a connection, with each jack 14 there is associated a plane of motion in which it moves according to the movements α, β and τ or combinations thereof. The planes of motion are illustrated in Figure 4 in their projection onto the second plate 32, and are denominated respectively PI, P2 and P3. In general, the jacks 14 are connected to the base 12 at points disposed preferably at 120° to one another and in any case' such that the plane of motion of each jack 14 never coincides with that of another jack 14. The jacks 14 are further preferably mounted so as to be inclined, in a rest position, by a predetermined angle with respect to the base 12, in order better to oppose the forces transverse to an axis H of symmetry of the mixer (projected onto the base 12 in Figure 3) which are generated during the motion of the plate 16.

Each jack 14 has at the end opposed to the hinge 36 a hinge 38, as illustrated in Figure 1 which, preferably, but not by way of limitation, is of an alternative type to that of the hinge 36 of the same jack 14, selected from a ball-and-socket joint or a revolute pair. The hinges 38 connect the jacks 14 to the plate 16 on which is fixed a clamping device 42 for clamping the container 18.

Some examples of clamping device 42 are illustrated respectively in Figures 14 and 15. The clamping device 42 of Figure 14 comprises a box 44, preferably cylindrical in shape, fixed on the plate 16, with an inner space 46 of dimensions such as to accommodate the container 18 so that during use it remains fixed inside it. The box 44 is also provided with a lid 48, lockable above an opening 50 of the space 46 through which the container 18 is introduced, for example by means of the screw threaded portion 52, to retain the container 18 inside the space 46 during use.

The clamping device 42 of Figure 15 comprises a jaw 54 fixed to the plate 16 and clamped, in use, to the bottom of the container 18 by means of a clamping screw 56, such that, in use, it retains the container 18 by friction.

With reference now to Figures 1 and 6, the control unit 20 for controlling the jacks 14 preferably comprises pneumatic valves 58, mounted singly or in a pack on the second plate 32, and controlled electrically by the control system 24 by means of independent commands, for example electrical pulses, sent through the channels 22, comprising for example electric connection cables. The valves 58, preferably of the 3 -way 2 position type, have two apertures 60 and 62 for the passage of the compressed air, communicating alternatively and selectively with two air supply pipes 64 and 66, which open respectively into a first and a second pressure chamber 68 and 70 produced in a casing 72 of each jack 14 on opposed faces of a piston 74 slidable within the casing 72. On the air supply pipes 64 and 66, air recirculation circuits 76 are provided which preferably comprise a non-return valve and a filter. A supply network 78 supplies compressed air to the valves 58. Alternatively, the control unit 20 may comprise a harness (not illustrated) of pipes and/or electric cables assembled so as to operate the actuators 14, of whatever type they may be, with a predetermined sequence of commands depending on the conformation of the harness and independent of the control system 24. In order to vary the sequence of commands in this case it is necessary to modify the conformation of the harness.

The control system 24 preferably comprises an electronic processor 80 equipped with a connection port 82 to which the electric cables 22 are connected, and with a communication interface 84 with an operator, provided with data insertion means 86, such as, for example, a driver for the insertion of diskettes on which is stored the mixing program for a new type of product to be mixed.

Figure 2 illustrates an embodiment of the mixer 10 in which the base 12 comprises a fixed plate 26, on which are fixed the hinges 36, all of the ball-and-socket joint type. The hinges 38 comprise pairs of projections 88 on the lateral edge 90 of the plate 16, each of which supports a pin 92 to which is coupled, swinging, one end 94 of a jack 14.

Figure 5 shows a further embodiment of the mixer 10, in which the base 12 comprises a shock absorbing plate 96, secured to the fixed plate 26 by means of shock absorbers 98, preferably comprising resilient means 100 and dampers 102. The hinges 36 are fixed on the shock absorbing plate 96. In a preferred variant (Figure 16) the base 12 comprises a second shock absorbing plate 99, mounted above the shock absorbing plate 96, and secured to the latter by means of shock absorbers 98 similar to the shock absorbers between the shock absorbing plate 96 and the fixed plate 26. Moreover, preferably, but not by way of limitation, the shock absorbing plate 96 has a weight about double that of the second shock absorbing plate 99.

With reference now to Figures 9 and 10, a preferred embodiment of the invention comprises a cylinder 104, rigidly fixed to the fixed plate 26 so as to project in the direction of the length towards the plate 16. Inside the cylinder 104 a cylindrical cavity 106 is provided which extends in the direction of the length of the cylinder 104 and inside which is slidably mounted a second cylinder 108, coupled, for example via a ball-and-socket joint 110, to the centre of the plate 16. On the longitudinal outer surface portion 112 of the cylinder 104, a locking means 114 is provided, for example a laterally protruding step, for a guide 116. The guide 116 has the function of delimiting the space within which the jacks 14 can move, only one of which jacks has been shown for the sake of simplicity, all being connected both to the fixed plate 26 and to the plate 16 by means of ball-and- socket joints 36 and 38, and therefore movable in the space and not on the planes of motion PI, P2 and P3. The guide 116 preferably comprises a rigid, flexible disk with a hole 118 at the centre into which the cylinder 104 is slipped as far as the step 114, so that the disk 116 projects parallel to the fixed plate 26. On the periphery of the disk 116, receiving holes 120 are provided, inside each of which fits a jack 14.

Referring now to Figure 11, a further embodiment of the mixer 10 comprises a cylindrical body 122 slidably mounted in the cavity 106 of the cylinder 104, in its turn mounted as in the preceding embodiment. The cylindrical body 122 is appended on the plate 16 via a spring 124 and a ball-and-socket joint 110, which permits the inclination of the plate 16.

The mixer 10 may also comprise a damping device 126 for damping the forces of inertia which are generated during the mixing cycle. Figures 12 and 13 show two examples thereof. The first comprises a first swinging body 128 coupled to the fixed plate 26 or to the second plate 32 by means of a first spring 130, and a second swinging body 132, preferably like the first, to which it is coupled via a second spring 134, preferably with characteristics similar to the first spring 130. The arrow X indicates the preferential direction of swing of the first and of the second swinging body 128 and 132.

The example of Figure 13 represents a damping device 126 which comprises only a first swinging body 128 coupled to the fixed plate 26 or to the second plate 32 by means of a first spring 130.

Alternatively, the device 126 may provide for the first swinging body 128 to be coupled to the plate 16, or it is possible to couple a damping device 126 both to the base 12 and to the plate 16.

In use, a container of paint base, to which a predetermined dose of colouring agent has already been added, is positioned on the plate 16, locking it with a clamping device 42, for example of the type according to Figure 14 or 15. The operator selects by means of the electronic processor 80 a drive sequence or law for the jacks 14, based on the type of product contained inside the container 18. The drive sequence may be already stored within the processor 80, or may be suitably created by the operator acting via the communication interface 84. Alternatively, it is possible to introduce into the processor a drive sequence developed elsewhere and stored on an information technology support, such as a diskette or a CD, inserted into the data insertion means 86. Alternatively, the electronic processor 80 carries out an analysis of the product contained in the container 18 and automatically selects the most suitable drive sequence, for example by searching for it via a network connection in an electronic archive of the firm supplying the product.

At this point the electronic processor 80 operates the valves 58 via electric pulses transmitted by the cables 22, so that the valves 58 send a series of independent commands to the jacks 14, according to the predetermined drive sequence. Owing to the independent control of each jack 14, it is possible to actuate only one jack 14 at a time or a series of jacks 14 simultaneously, or also partially superposed for periods. The resulting motion imparted to the container 18 therefore results from the composition of a plurality of motions of the individual jacks.

Figures 7 and 8 illustrate two examples of a drive sequence for the three jacks 14, denominated respectively A, B and C. In the first example, each jack is actuated when the preceding one has finished its outward and return stroke and all the others are closed. A sequence of this type is easily reproducible also by means of the harness of the valves 58 with cables which receive the electrical control pulses from electrical equipment which distributes them in succession among the valves, without the need for the processor 80. In the example of Figure 8, on the other hand, each graphic refers to the signal for actuation of a jack 14, from which it can be seen that the 3 jacks 14 are actuated for overlapping and equal periods, or multiples of a base period T. The total actuation time of the jacks 14, and therefore the duration of mixing, is indicated by the segment Tc .

Other preferred drive sequences for the jacks 14 (not illustrated) are comprised in the following list, in which each step is understood to succeed the preceding one and to be arranged as it appears in the list:

• sequence LI comprising the steps of:

- actuating A for a period T;

- passing through a rest period T;

- actuating B for a period T;

- passing through a rest period T;

- actuating C for a period T;

- passing through a rest period T; and

- actuating B for a period T;

• sequence L2 comprising the steps of

- actuating A and B simultaneously for a period T; and

- actuating C for a period T; • sequence L3 comprising the steps of:

- actuating A and B simultaneously for a period T;

- passing through a rest period T;

- actuating B and C simultaneously for a period T;

- passing through a rest period T; and

- actuating A and C simultaneously for a period T;

• sequence L4 comprising the steps of:

- actuating A, B and C simultaneously for a period T;

• sequence L5 comprising the steps of :

- actuating A for a period T;

• sequence L6 comprising the steps of:

- actuating A, B and C simultaneously for a period T; and

- actuating C for a period T;

• sequence L7 comprising the steps of:

- actuating A and B simultaneously for a period T; and

- passing through a rest period T;

• sequence L8 comprising the steps of :

- actuating A and B simultaneously for a period T;

- actuating C for a period T;

- passing through a rest period T;

- actuating A and C simultaneously for a period T;

- actuating B for a period T;

- passing through a rest period T;

- actuating B and C simultaneously for a period T; and

- actuating A for a period T;

• sequence L9 comprising the steps of:

- actuating A and B simultaneously for a period T;

- actuating A, B and C simultaneously for a period T;

- passing through a rest period T;

- actuating A for a period T;

- actuating A, B and C simultaneously for a period T; and - actuating B and C simultaneously for a period T;

* sequence L10 comprising the steps of:

- actuating A for a period T;

- actuating A, B and C simultaneously for a period T; and

- actuating B and C simultaneously for a period T;

* sequence Lll comprising the steps of:

- actuating A and B simultaneously for a period T;

- actuating A, B and C simultaneously for a period T;

- actuating C for a period T;

- passing through a rest period T;

- actuating B and C simultaneously for a period T; - actuating A, B and C simultaneously for a period T;

- actuating A for a period T;

- passing through a rest period T;

- actuating A and C simultaneously;

- actuating A, B and C simultaneously for a period T; and

- actuating B for a period T;

* sequence L12 comprising the steps of:

- actuating A for a period T;

- actuating A, B and C simultaneously for a period T;

- actuating B and C simultaneously for a period T;

- passing through a rest period T;

- actuating B for a period T;

- actuating A, B and C simultaneously for a period T;

- actuating A and B for a period T;

- passing through a rest period T;

- actuating C for a period T;

- actuating A, B and C simultaneously for a period T; and

- actuating A and B for a period T;

* sequence L13 comprising the steps of:

- actuating A for a period T;

- actuating B for a period T; and - actuating C for a period T;

* sequence L13P comprising the steps of:

- actuating A for a period T;

- passing through a rest period T;

- actuating B for a period T;

- passing through a rest period T; and

- actuating C for a period T;

* sequence L14 comprising the steps of:

- actuating A and B simultaneously for a period T;

- actuating C for a period T;

- actuating A and B simultaneously for a period T;

- actuating C for a period T;

- passing through a rest period T;

- actuating A and B simultaneously for a period T;

- passing through a rest period T; and

- actuating A and B simultaneously for a period T.

The electronic processor 80, besides the drive sequence, is capable of controlling and imposing other parameters for actuation of the jacks 14, such as, for example, the total duration and the number of repeats of the drive sequence, the force and the stroke of each jack 14, and the number of shakes executed in each plane of motion PI, P2 and P3. The preferred drive frequencies of the jacks range between 1.125 Hz and 4 Hz for each jack, with particularly satisfactory results for 1.125, 1.5, 1.875, 2, 2.25, 3, 3.75 and 4 Hz, or between 9 and 16 Hz, with particularly satisfactory results for 9, 12, 15 and 16 Hz, or in any case within limits which allow the completion of the stroke of each jack 14. The pressures of the compressed air with which the jacks 14 are supplied on the other hand preferably range between 2.5 and 8 bar, with particularly satisfactory results for 2.5, 5 and 8 bar. The total time Tc of actuation of the jacks 14 is preferably selected to be three minutes or less. From what has been stated, it is possible to carry out a mixing method which comprises the steps of : arranging a mixer 10 comprising sensors 140 (Figure 1) for measuring the value of a characteristic parameter, or of a plurality of characteristic parameters, of the operation of the mixer 10, such as the acceleration, speed or direction of motion of the plate 16; comparing the measured values of the characteristic parameter or parameters with values of the characteristic parameter predetermined in accordance with a desired motion of the plate 16, such as, for example, a flat motion, and determining the difference therefrom; controlling the drive sequence and/or imposing the characteristic parameters of the actuators or jacks 14, such as the frequency, stroke and supply pressure, according to the difference in value.

The advantages linked to a drive sequence selected from among those described may be summarised as follows:

• the sequence LI does not trigger the rotation of the machine about its own axis, as occurs on the other hand if the rest periods T are not applied;

• the sequence L2 maximises the angular velocity of the paint in the container 18, in order to obtain thorough mixing also at the walls of the container 18;

• the sequence L3 doubles the thrust force with respect to LI;

• the sequence L6 is held to be particularly advantageous if applied in association with an inclined starting position of the container 18, which is an expedient that can be adopted with any sequence that may be used;

• the sequence L8 is a development of L2 and consists in maximising the angular velocity by imposing a shaking motion on all three planes of motion PI, P2 and P3 ;

• the sequence L9 is termed a recirculation sequence, in so far as it creates within the container 18 a circular motion of the paint relative to the container 18. The whirling flow which is produced is particularly effective for mixing the paint attached to the walls of the container 18.

• the sequence Lll applies the same principle of recirculation as L9 but applied to all three planes of motion PI, P2 and P3 ;

• the sequence L14 is an example of combination of sequences L2 and L3.

One of the principal advantages of the mixers according to the present invention is that of having a movable part comprising the plate 16 of very contained size and weight, therefore easily displaceable without high forces of inertia arising.

Another advantage is linked to the presence of the damping device 126, in the versions in which it is adopted. The latter in fact reduces the action of the forces of inertia, which tend to displace the base 12 from the bearing zone, and consequently makes it possible to reduce or eliminate the ballast means 28 and keep the mixer light in weight and therefore transportable. Moreover, the adoption of the second plate 32, movable with respect to the fixed plate 26 of the base 12 owing to the shock absorbers 98, increases the stability of the base 12 against lateral displacement and tipping, while the variant with two damping plates 96 and 99 is particularly effective in the case of high frequency operation.

The application of a drive frequency of the jacks 14 such as to allow the completion of the stroke favours the occurrence of impacts when the pistons 74 reach the dead centres. This is a further aspect which has an advantageous influence on the mixing result . A mixer 10 according to the present invention may be used for preparing and studying personalised mixing sequences in association with an advantageous method of checking the quality of mixing reached by the paint contained in the container 18, which is added, as a final step, to the mixing methods described above. This method of checking the mixing quality comprises the steps of carrying out a mixing process according to one of the methods previously illustrated, and then freezing the container 18 with the mixed paint inside. Once the paint is completely frozen, it is dissected and/or broken up to check the degree of homogenisation reached within the volume and on the periphery by the base and the colouring agent which form the paint . An expert in the field will of course recognise the applicability of such a method in association with any mixing method carried out with any type of mixer, and will know how to apply it to any type of mixed fluid that can be frozen.

Alternatively or in addition to the final freezing of the fluid product, it is possible to test the efficacy and quality of mixing by observing the motion of the fluid during the period of actuation of the actuators by means of the use of a transparent container 18.

Numerous variants of the mixer with respect to what has been described above by way of example are of course possible. In particular, the plate 16 may be mounted with a general capacity for rotation and/or swinging with respect to the base 10, so as to impart an additional motion to the container with respect to that provided by the linear actuators .

With the principle of the invention remaining unchanged, the constructional characteristics and the embodiments may of course vary widely with respect to what has been written and illustrated, without thereby departing from the scope of the present invention.

Claims

1. A mixer for fluid products, such as paints, varnishes, colouring agents and the like, comprising a main base (12) ; a support member (16, 42) for at least one container (18) of fluid products; movement means (14, 36, 38) for moving the support member (16) with respect to the main base (12) ; and control means (20) for controlling the movement means (14) for imparting a selective mixing motion thereto; characterised in that the movement means (14) comprise actuator members (14) coupled to the support member (16) , and operable independently from one another by the control means (20) according to a predetermined drive sequence or law.

2. A mixer according to claim 1, characterised in that the main base (12) comprises a fixed part (26) and a movable part

(32, 96) connected to the fixed part (26) via shock-absorbing means (34, 98), the support member (16) being coupled to the movable part (32) .

3. A mixer according to claim 2, characterised in that the movable part comprises a first movable part (96) and a second movable part (99) secured to the first movable part (96) via shock-absorbing means (98) .

4. A mixer according to one of the preceding claims, characterised in that it comprises a guide (116) coupled to the support member (16) in order to limit the movement thereof in use.

5. A mixer according to claim 4, characterised in that the guide (104, 108, 116) comprises a first body (104) rigidly connected to the main base (12) and a second body (108) connected to the support member (16) via a ball-and-socket joint (110) and telescopically coupled to the first body (104) .

6. A mixer according to any one of the preceding claims, characterised in that the actuator members comprise at least three linear actuators (14) .

7. A mixer according to claim 6, characterised in that each of the linear actuators (14) is coupled to the main base (12) and to the support member (16) via ball-and-socket joints

(36, 38), constraining means (116) being comprised in order to limit the movement of the linear actuators to a predetermined work zone .

8. A mixer according to claim 6, characterised in that the linear actuators (14) are coupled to the main base (12) via revolute pairs (36) and to the support member (16) via ball- and-socket joints (38), or vice versa.

9. A mixer according to claim 6, characterised in that the linear actuators (14) comprise hydraulic and/or pneumatic jacks .

10. A mixer according to claim 9, characterised in that the control means (20) comprise control valves (58) for controlling the jacks (14) .

11. A mixer according to any one of the preceding claims, characterised in that it comprises a control system (24) for transmitting commands to the actuator members (14) via the control means (20) .

12. A mixer according to claim 11, characterised in that the control means (24) comprise an electronic processor (80) .

13. A mixer according to claims 10 and 12.

14. A mixer according to any one of the preceding claims, characterised in that it comprises damping means (126) coupled to the main base (12) , to absorb, in use, at least part of the forces of inertia generated by the action of the actuator members (14) on the support member (16) .

15. A mixer according to any one of claims 1 to 11, characterised in that it comprises damping means (126) coupled to the support member (16) , to absorb, in use, at least part of the forces of inertia generated by the action of the actuator members (14) on the support member (16) .

16. A mixer according to claim 14 or claim 15, or in combination with each other, characterised in that the damping means (126) comprise a damping mass (128) connected to the main base (12) or to the support member (16) by resilient means (130) .

17. A mixer according to claim 16, characterised in that it comprises a second damping mass (132) coupled to the damping mass (128) by second resilient means (134) .

18. A mixer according to claim 15, characterised in that the damping means (126) comprise a damping mass (122) coupled through resilient means (124) and a ball-and-socket joint (110) to the support member (16), the damping mass (122) being slidable in a guide (104) coupled to the main base (12) .

19. A mixer according to any one of the preceding claims, characterised in that the support member (16, 42) for at least one container of fluid products is mounted movable with respect to the main base (12) , independently with respect to the motion of the actuator members (14) .

20. A mixer according to claim 19, characterised in that the support member (16, 42) is mounted so as to rotate and/or swing with respect to the main base (12) .

21. A method for mixing fluid products, for example colouring agents, paints or the like, by means of a mixer (10) according to any one of the preceding claims, comprising the steps of: placing a container (18) of fluid products on the support member (16) of the mixer (10) ; actuating the control means (20) , for a predetermined period (Tc) , to operate the actuator members (14) coupled to the support member (16) according to a drive sequence or law comprising a plurality of independent commands, sent by the control means (20) to each actuator member (14) ; and deactivating the control means (20) at the end of the predetermined period (Tc) .

22. A mixing method according to claim 21, characterised in that it comprises the steps of : arranging a control system (24) for controlling the actuation of the actuator members (14) through the control means (20) ; and actuating the actuator members (14) in a predetermined sequence by means of the control system (24) .

23. A mixing method according to claim 21 or claim 22, characterised in that it comprises the step of actuating a first, a second and a third actuator member (14), hereinafter respectively A, B and C, in a sequence or law of motion selected from among the following:

• sequence LI comprising, in succession, the steps of: actuating A; passing through a rest period; actuating B; passing through a rest period; actuating C; passing through a rest period; and actuating B;

• sequence L2 comprising, in succession, the steps of: actuating A and B simultaneously; and actuating C;

• sequence L3 comprising, in succession, the steps of: actuating A and B simultaneously; passing through a rest period; actuating B and C simultaneously; passing through a rest period; and actuating A and C simultaneously;

• sequence L4 comprising, in succession, the steps of: actuating A, B and C simultaneously;

• sequence L5 comprising, in succession, the steps of: actuating A;

• sequence L6 comprising, in succession, the steps of: actuating A, B and C simultaneously; and actuating C;

• sequence L7 comprising, in succession, the steps of: actuating A and B simultaneously; and passing through a rest period; and

• sequence L8 comprising, in succession, the steps of: actuating A and B simultaneously; actuating C; passing through a rest period; actuating A and C simultaneously; actuating B; passing through a rest period; actuating B and C simultaneously; and actuating A;

• sequence L9 comprising, in succession, the steps of: actuating A and B simultaneously; actuating A, B and C simultaneously; passing through a rest period; actuating A; actuating A, B and C simultaneously; and actuating B and C simultaneously;

• sequence L10 comprising, in succession, the steps of: actuating A; actuating A, B and C simultaneously; and actuating B and C simultaneously;

• sequence Lll comprising, in succession, the steps of: actuating A and B simultaneously; actuating A, B and C simultaneously; actuating C; passing through a rest period; actuating B and C simultaneously; actuating A, B and C simultaneously; actuating A; passing through a rest period; actuating A and C simultaneously; actuating A, B and C simultaneously; and actuating B;

• sequence L12 comprising, in succession, the steps of: actuating A; actuating A, B and C simultaneously; actuating B and C simultaneously; passing through a rest period; actuating B; actuating A, B and C simultaneously; actuating A and B; passing through a rest period; actuating C; actuating A, B and C simultaneously; and actuating A and B;

• sequence L13 comprising, in succession, the steps of: actuating A; actuating B; and actuating C • sequence L13P comprising, in succession, the steps of: actuating A; passing through a rest period; actuating B; passing through a rest period; and actuating C;

• sequence L14 comprising, in succession, the steps of: actuating A and B simultaneously; actuating C; actuating A and B simultaneously; actuating C; passing through a rest period; actuating A and B simultaneously; passing through a rest period; and actuating A and B simultaneously.

24. A mixing method according to one of claims 21 to 23, characterised in that the control system (24) selects the drive sequence with which to operate the control means (20) and imposes or modifies the characteristic parameters of operation of the actuator members (14) .

25. A mixing method according to claim 24, characterised in that the characteristic parameters imposed or modified by the control system (24) comprise the drive frequency of the actuator members (14) and the total duration (Tc) of the drive sequence; the drive frequency ranging between 9 and 16 Hz, and the total duration (Tc) being three minutes or less.