Device for dosing dyes for the preparation of dyeing baths.

DESCRIPTION

The present invention relates to a device, in particular a multi-pipette device, for dosing colouring agents in the form of a solution or dispersion destined to the preparation of dyeing baths for textile materials.

Known devices comprising more pipette-distributors are used to contemporarily distribute and to dose more liquid products in order to minimize the time necessary for the preparation of solutions based on formulations or "recipes" which require more components.

The said devices function according to the diagram shown in Fig. 1 : a three-path valve (V) is mounted on the exit of each pipette (P) which is electronically operated and connected to a bottle (B) containing a liquid component by means of a first conduit (Cl), and to the same pipette (P) and, on the exit, with a second conduit (C2) ending in a dosing head (not shown) into which analogous conduits from other valves, singularly mounted on their corresponding pipettes, converge. One of the main drawbacks connected with the use of said device arises from the fact that the conduits (C2) connecting each of said thee-path valves (V) to the dosing head are extremely long and full of liquid drawn from the corresponding bottles (B) , so the liquid is replaced in said conduits only when the dosage of the products that they contain is executed. In other words, the product contained in each of the conduits ending in the dosing head stagnates therein, until a further distribution of the product in the programmed cycle takes place. A prolonged permanence of the product in the conduit

(C2) causes the sedimentation of the solute in the lower part and on the walls of the conduit with evident precision problems in the subsequent measurements .

Moreover, due to the length of the conduits (C2) an undesired dripping of the product during the dosing of the other components may take place and, consequently, an incorrect execution of the programmed formula may be performed.

A further drawback arises from the fact that the length of the conduit (C2) varies from pipette to pipette .

The main aim of the present invention is to eliminate, or at least to remarkably reduce, said drawbacks .

These results have been achieved, according to the present invention, by adopting the idea of making a device having the features described in claim 1. Further features of the present invention are the subject of the dependent claims.

Thanks to the present invention, the conduits connecting the three-path valves to the dosing head can conveniently be shortened and do not exhibit sedimentation or dripping problems. Moreover, a device according to the present invention is relatively easy to build, reliable and economical in comparison with the advantages that it offers. Every technician who works in this field will better understand these advantages and further advantages and features of the present invention thanks to the following description and to the enclosed drawings which are provided for illustration purposes but should not be considered in a limitative sense, wherein:

Fig.l shows a diagram concerning a known device;

Fig.2 shows a functional diagram which is graphically analogous to the device shown in

Fig.l but refers to a part of a device according to the present invention ;

Fig.3 schematically shows a device according to the present invention;

- Fig.4 shows the device of Fig.3 during the aspiration of the liquid contained in one of the bottles, in which, for simplification's sake, only part of the device is shown to better illustrate the functioning thereof;

- Fig.5 shows the device of Fig. 3 , in .the same way as Fig.4, in a dosing phase;

Fig.6 shows the device of Fig.3, in the same way as Figs. 4 and 5, in a recirculation phase of the liquid;

- Fig.7 shows an enlarged detail of the device shown in Figs.3-6.

Reduced to its essential structure and with reference to Figs.2-6 of the enclosed drawings, a device according to the present invention comprises:

- a set of pipettes (1) mounted on a horizontal bar (2 ) vertically moved by an actuator (3), so that the movement of the bar (2) by means of the actuator (3) determines the corresponding lowering or raising of the piston (10) of each pipette (1);

- a plurality of three-path electro-valves (4), each of which is connected

(a) to a corresponding pipette (1) by means of a first conduit (5); (b) to a corresponding bottle (6) by means of a second conduit (7), and

(c) to a dosing head (8) by means of a third conduit ( 9) .

In practice, the electro-valves (4), the conduits

(5), the bottles (6), the conduits (7) and the conduits (9) are in a number which is equal to the number of the pipettes (1) .

The bottles (6) contain liquid substances which constitute the components of the formulations or recipes to be prepared as further indicated in the following. In particular, the bottles (6) contain colouring agents in solution or dispersion destined to the preparation of dyeing baths for textile materials.

The end (90) of the conduits (9) which converge into the dosing head (8) exits from the latter and extends underneath it along a portion of length which is not relevant if compared with the length of the conduits (9). In other words, the dosing head (8) exhibits a series of lower nozzles, each or which consists of the end (90) of a corresponding conduit ( 9) .

Said bar (2) is mounted on vertical rods (20) passing through corresponding guiding bushes (21) presented by the same bar (2). The actuator (3) consists of a stepper motor and is attached to the lower base of a fixed frame (22) and, by means of a bilateral belt transmission (23), it drags into rotation two threaded vertical rods (24) passing through corresponding threaded bushes presented by the fixed frame (22) . Said bar (2) is fixed on the upper ends of the threaded rods (24). The piston (10) of each pipette (1) is fixed to the mobile bar (2), whereas the shirt (11) of the pipette is attached to a fixed bar (25) in correspondence of the upper part thereof, that is to say to the fixed part of said frame. Therefore, by operating the actuator (3), that is to say by rotating the rods (24) in the clockwise and counter-clockwise direction, it is possible to obtain the lowering and the raising of the pistons (10) . As shown in Fig. 7 C, an end cap (12) provided with a central hole, on which one end of a corresponding conduit (5) engages, is fixed on the upper part of the shirt (11) of each pipette (1).

The electro-valves (4), the conduits (5, 7, 9) and the bottles (6) are fixed, that is to say positioned in fixed and predetermined positions.' The actuator (3) and the electro-valves (4) are connected to a programmable electronic unit (UE) for simplification's sake shown only in Fig. 3 with the corresponding connections indicated with dashed lines - in which it is possible to memorize the quantities of each of the products contained in the bottles (6) to be distributed- according to the recipes or formulations to be executed. Said programmable unit (UE) controls the conditions of the actuator (3) and of each of the electro-valves (4). Since the quantity of product distributed by each pipette (1) depends on the run of its corresponding piston (10) and the run depends on the number of steps of the actuator (3) during the raising of the bar (2), the unit (UE) commands the state variation of each electro-valve (4) - as further described in the following - depending on the number of steps of the actuator (3) .

It goes without saying that the actuator (3) can be of any other electronically controllable type.

The device described above can be programmed to work as follows.

In a first phase (see. Fig.4), each of the electro- valves (4) connects the corresponding conduits (5) and (7) to each other, the bar (2) is lowered and, consequently, the .pistons (10) of the pipettes (1) are lowered so as to cause the aspiration of liquid from the bottles (6) as indicated by the arrows represented next to the conduits (5) and (7). In this phase, the passage of the liquid takes place through the conduits (5) and (7), whereas the conduits (9) and the dosing head (8) are excluded from said passage In this way, it is possible to obtain the loading of each of the pipettes (1) with the liquid contained in the bottle to which it is connected by means of the corresponding conduits (5) and (7).

In a subsequent phase, depending on the recipe or on the formulation to be executed, a first group of electro-valves (4) connect to each other the conduits (5) and (9) corresponding to the pipettes (1) from which the liquid is to be extracted to execute the recipe, whereas the conditions of a second group, formed by the remaining electro- valves (4), remains unchanged to maintain the connection between the corresponding conduits (5) and (7) thereof. At this point, the bar (2) is raised and, consequently, the pistons (10) of the pipettes (1) are raised and the liquid passes through the conduits (5) and (9) intercepted by the electro-valves (4) of the first group (as schematically represented in Fig.5) and through the conduits (5) and (7) intercepted by the electro- valves (4) of the second group (as schematically represented in Fig.6). Therefore, through the dosing head, (8) there is only the passage of the liquid coming from the conduits (5) and (9) which are connected to each other by means of the electro-valves (4) of the first group, whereas the liquid coming from the conduits (5) and (7) connected to each other by the electro-valves (4) of the second group returns to the respective bottles (6). Each of the electro-valves (4)of the first group is then brought back to its initial condition (re-connecting to each other the corresponding conduits 5 and 7) when the quantity of liquid corresponding to the programmed formulation is reached. Said condition is detected by the unit (UE) through the control of the number of steps of the actuator (3) . Therefore, the liquid substances return to their corresponding bottles (6), both when their use is not foreseen in a programmed formulation, and at the end of the dosing phase.

According to the present invention, it is therefore possible to obtain, depending on the programmed formulation, (quantity and type of liquid) , the automatic subdivision or automatic selection of the electro-valves (4) into two groups , wherein:

- a first group of electro-valves (4) which initially connect their corresponding bottles

(6) to their corresponding pipettes (1) by means of the conduits (5) and (7), analogously to the electro-valves (4) of the second group, and which, in a subsequent phase, connect their respective pipettes (1) to the dosing head (8) by means of the conduits (5) and (9) and then individually provide the initial connections after the dosing phase has taken place; and

- the electro-valves (4) of the second group constantly maintain the connection between their respective pipettes (l)and their corresponding bottles (6) .

By the word ^' "group" it is meant a number of electro-valves or even a single unit.

Since the electro-valves (4) are mounted in correspondence of the dosing head (8), the conduits (9) have a reduced length.

Moreover, the liquids which are not involved in the dosage, that is to say those which do not pass through the conduits (9), are always moved (from the bottles 6 to the pipettes 1 or vice-versa). Therefore, there will not be experienced the problems connected with the sedimentation of liquids in the conduits (5, 7, 9) of the device.

In practice, the construction details may equally vary as regards the single described and illustrated elements, without nevertheless departing from the adopted solution idea and within the limits of the protection granted to the present patent .