EP0606798B1 - Proportioning devices for distributing volumes of products and method for mixing them - Google Patents

Description

• une chambre de volume variable, fermée à une extrémité par un organe de fermeture,
• des moyens de liaison de la chambre avec l'extérieur,
• et des moyens de commande des variations du volume de la chambre pour assurer une aspiration ou un refoulement selon que la chambre augmente ou diminue de volume.

The invention relates to a metering device for withdrawing a volume of liquid, pasty or pulverulent product, from at least one reservoir and for then dispensing all or part of the volume withdrawn, of the type of those which include:

• a chamber of variable volume, closed at one end by a closure member,
• means of connecting the room with the outside,
• and means for controlling variations in the volume of the chamber to ensure suction or discharge depending on whether the chamber increases or decreases in volume.

Such a device can be used to collect and distribute a single product in a metered amount. It is interesting, however, that such a device can be used, without having to be modified appreciably, for a sequential sampling of several different products, for mixing these products and for distributing the mixture.

US-A-5,078,302 relates to an apparatus for taking metered amounts of paints of different colors from different tanks and for mixing the metered amounts. The tanks containing the paints of different colors are mounted on a turntable allowing to place, successively, each tank in which a sample must be taken at the level of a sample station. Each pump is associated with a pump constituted by a piston / cylinder assembly. A valve of a particular type is provided to cooperate with a cylinder base and allow, for one position, the suction of the liquid to be withdrawn from the reservoir and, in another position, the delivery of the withdrawn quantity of liquid.

Such a device is relatively complicated, bulky and expensive.

The object of the invention is, above all, to provide a metering device for withdrawing a volume of product and then for dispensing all or part of the volume withdrawn, of the kind defined above, which is as simple as possible, compact, robust, of a reliable operation, and which ensures the integration of several functions: intake-suction, controlled distribution. It is moreover desirable that such a metering device make it possible to ensure, with additional means that are as small as possible, the integration of the function of sampling several determined volumes of different products, and of the mixing function, with agitation, of these different volumes withdrawn, which are then to be distributed.

A metering device according to the invention for withdrawing a volume of product, liquid, pasty or pulverulent, from at least two reservoirs and for then dispensing all or part of the volume withdrawn, of the kind defined above, is defined by claim 1 and claims 2 to 13 dependent thereon.

Thus, according to the invention, the entry of the withdrawn product, into the variable volume chamber, takes place in a different location from that through which the product passes for distribution.

Advantageously, the piston is kept fixed relative to the reservoir, while the control means ensure displacement alternative in translation of the cylinder, along its axis, relative to the piston.

Advantageously, the shutter constitutes the bottom of a cylindrical barrel, in which the piston is engaged, said barrel having an axial length greater than that of the cylinder so as to keep a part outside of the cylinder, when the barrel is completely pressed into the cylinder, the outer part of the barrel comprising means for driving this barrel in rotation about the geometric axis of the cylinder, the piston having a part which remains outside the barrel.

Preferably, these drive means comprise a ring gear whose mean plane is orthogonal to the axis of the barrel, this ring gear being able to cooperate with a pinion driven by an electric motor, in particular a stepping motor.

Advantageously, the shutter and the barrel are centered and fixed on the end of a rod mounted to rotate in an axial bore of the piston.

Preferably, for a sequential sampling of several products, the chamber closing member, in particular the piston, comprises several parallel channels distributed around the axis, each channel, except one, being connected to a different liquid reservoir. , the last of these channels being connected to a mixing chamber. Each channel of the piston connected to a product reservoir can be provided, at its lower end, with a non-return valve while the channel connected to the mixing chamber is devoid of such a non-return valve.

The means for closing the dispensing orifice is itself constituted by a valve calibrated at a sufficient level, in particular at 4 newtons (400 grams force), so as to open only for one pressure much higher than that required to pass the product (s) into the mixing chamber.

The movement in translation of the cylinder can be controlled by an electric motor, in particular step by step, controlling a screw, for example of the ball type, which acts on a nut linked to the cylinder.

The device may comprise a multi-compartment reservoir, each compartment being connected to a channel of the closure member, in particular of the piston, all the compartments except one being assigned to a product, the last of these compartments constituting a mixing chamber, this multi-compartment container being fixed directly above the outer face of the closure member, or of the piston, where the channels open.

A thermostat with heating resistance can be provided, in the heart of the tank, and be integrated into the system.

As a variant, the different products can be contained in reservoirs separated from each other, each reservoir being connected by a tube, as small as possible, at the end of a channel of the piston, a reservoir, initially devoid of product, serving as a mixing tank and also being connected to a piston channel.

The invention also relates to a method for mixing the various products with a device as defined above.

According to this process, the necessary volumes of the different products are sequentially withdrawn from the chamber of variable volume to carry out the mixing, and all of these sampled products are discharged into a mixing chamber and, by successive alternating movements, they are aspirated and discharged mixing from the mixing chamber to the variable volume chamber and vice versa, so as to homogenize the mixture.

The invention consists, apart from the arrangements set out above, of a certain number of other arrangements which will be more explicitly discussed below in connection with embodiments described with reference to the attached drawings, but which are in no way limiting.

Figure 1 of these drawings is a partial sectional view, axial vertical and schematic of a metering device according to the invention, the variable volume chamber having an average volume.

Figure 2 is a section along line II-II of Figure 1.

Figure 3 shows, similarly to Figure 1, the device while the volume of the chamber is minimum.

Figure 4 is a section along line IV-IV of Figure 3.

Figure 5 shows, similarly to Figure 1, the device while the volume of the chamber is substantially maximum.

Figure 6 is a section along line VI-VI of Figure 5.

Figure 7 is an exploded sectional view, on a larger scale, of the metering device equipped with a multi-compartment reservoir.

Figure 8, finally, is a section along line VIII-VIII of Figure 7.

Referring to the drawings, in particular to FIGS. 1 and 2, one can see a metering device D for withdrawing a volume of liquid or pasty product, or even powder, from at least one reservoir R very schematically represented. As an indication, the viscosity of the liquid or pasty products concerned by the invention can vary from 1 cp (one centipoise = 10 ^-3 Pa · s) to several thousand cp. The device D also makes it possible to distribute all or part of the volume withdrawn.

This device D comprises a chamber 1 of variable volume closed at one end, namely the upper end according to the representation in FIG. 1, by a closing member F.

Chamber 1 is limited by the internal wall of a cylinder 2 which has a bottom 3 provided with a dispensing orifice 4 equipped with a closure means C suitable for opening for dispensing, and advantageously constituted by a valve 5.

The cylinder 2 is fixed, towards its upper end, to a plate 6. This plate has a hole receiving the upper edge of the cylinder 2 which has a flange 7 crossed by holes allowing the cylinder to be fixed under the plate 6 using of screws engaged in tapped holes of said plate.

The plate 6 and the cylinder 2 can be moved in translation in a vertical direction relative to a frame 8 of which only a part is shown.

Means for driving the plate 6 and the cylinder 2 comprise an electric motor 9, preferably of the stepping type, the stator of which is fixed to the frame 8, for example with its vertical axis. The motor 9 rotates a screw 10, in particular a ball screw, of vertical axis, which cooperates with a corresponding nut carried by the plate 6 to transform the rotational movement into vertical translational movement.

The closing member F comprises a piston 11 whose axial length is greater than that of the cylinder 2. The upper part 12 of the piston 11 remains permanently outside the cylinder 2. This part 12 is fixed to the frame 8. The length of the piston 11 engaged in the cylinder 2 depends on the position, in the vertical direction, of the plate 6.

The piston 11 is crossed by at least one channel 13 which on one side, that is to say at its lower end, opens out towards the chamber 1 while on the other side, that is to say at its upper end, the channel 13 opens out towards the reservoir, forming a collar 14. In the embodiment considered, six channels similar to the channel 13, with axes parallel to that of the piston 11, are distributed regularly around this axis . Five of these channels have the same function, namely to allow the chamber 1 to be connected to a different liquid reservoir; these five channels are designated by the same reference numeral 13, possibly followed by one of the letters ad. Each of these channels 13, 13a-13d is provided, at its lower end, with a non-return valve 15 allowing a flow of liquid from the channel 13 to the chamber 1 but opposing a flow in the opposite direction. The non-return valves 15 are calculated, in closing, in order to ensure a sufficient seal to prevent any flow of product under its own gravity, the opening of the valve having to be ensured only when there is suction by descent of the cylinder 2. By way of example, the closing force of a non-return valve 15 is chosen to be approximately 0.1 N for a passage diameter of approximately 3 mm.

The sixth channel, designated by the reference numeral 16 does not have a non-return valve and is intended to be connected to a reservoir M forming a mixing chamber.

A selection means S is provided for connecting one of the channels 13, 13a-13d, 16, to the chamber 1, while the other channels are closed by this selection means.

The selection means S comprises a rotary shutter 17, in the form of a disc, applied against the end of the piston 11 situated inside the cylinder 2. The shutter 17 has a passage hole 18 suitable for coming in line with one end of a channel 13, 13a-13d or 16, to put this channel in communication with the chamber 1; a single channel can be put in communication through the hole 18 with said chamber, all the other channels being closed by the shutter 17. In an intermediate angular position, illustrated in FIG. 6, the hole 18 is located between two channels, at which in this case all the channels of the piston 11 are closed by the shutter 17.

This shutter 17 constitutes the bottom of a cylindrical barrel 19 in which the piston 11 is engaged. The barrel 19 has an axial length greater than that of the cylinder 12 so as to keep a part 20 outside of the cylinder 12 when the barrel is fully inserted into the cylinder 2 as illustrated in FIG. 3. The axial length of the barrel 19 is however less than that of the piston 11.

The shutter 17, and therefore the barrel 19, are centered and fixed on the lower end of a rod 21 rotatably guided by means of ball bearings, in the vicinity of each of these ends, in an axial bore of the piston 11. The shutter 17 is fixed, in its central part, on the lower end of the rod 21, for example using screws, while the upper end of the rod 21 is linked, according to the axial direction, to piston 11.

Means for rotating the barrel 19 and the shutter 17 around the axis of the piston 11 are provided. These drive means comprise a toothed crown 22 externally fixed to the barrel 19 at its upper end. The drive means further comprise an electric motor 23, preferably of the stepping type, the stator of which is fixed to the frame 8; the axis of this motor 23 is preferably vertical and drives a pinion 24 which, by an intermediate gear system 25, can cause the crown 22 to rotate about the axis of the piston.

As illustrated diagrammatically in FIG. 1, the different channels such as 13 can be connected, at their upper end, by a conduit 1 , of reduced length, to a liquid reservoir, specific to each channel.

According to the variant illustrated in Figure 7, a multi-compartment tank is fixed on the upper part 12 of the piston. This reservoir 26 comprises as many compartments 27, 27a-27d, 28 as there are channels in the piston 11. The reservoir 26 is constituted, for example, by a cylinder inside which are provided cylindrical chambers 27, 27a-27d and 28 regularly distributed around the axis of the cylinder. The lower end of these chambers is closed by the bottom of the tank which has inclined passages such as 29 connecting each compartment with the upper end of the corresponding channel of the piston 11. The upper ends of the compartments 27 ..... 28 are open.

Each compartment 27, 27a-27d is intended for a different liquid product, while the compartment 28 constitutes a mixing chamber.

A central cylindrical housing 30 is provided to receive, if necessary, an electrical resistance for thermostating the tank 26.

However, the operation of the metering device is as follows.

We first consider the case where the device D of Figure 1 is used to collect and distribute a single product.

In the rest position of the device D, illustrated in FIG. 3, the volume of the chamber 1 is zero, or almost zero, the cylinder 2 being raised as much as possible so that the shutter 17 is pressed against the bottom 3, conjugate form, of cylinder 2.

In view of the desired sampling, a rotation of the barrel 19 and of the shutter 17 is controlled, using the motor 23, itself controlled by instructions from an electronic assembly E, so as to place the orifice 18 in alignment with the channel 13 connected to the reservoir R from which it is desired to withdraw the liquid.

When the angular positioning of the shutter 17 is correct, the descent of the plate 6 and of the piston 2 is controlled by the activation of the motor 9 in the proper direction. The amplitude of the stroke of the cylinder 2 is determined by the calculation unit E to ensure the desired sampling.

The plate 6 and the cylinder 2 are stopped when this sampling has been carried out, for example when the chamber 1 occupies the average volume shown in FIG. 1.

The closing of the chamber 1 is then controlled by rotation of the shutter 17 in order to bring the orifice 18 between two channels, in a position similar to that illustrated in FIG. 6.

To distribute the withdrawn volume, the rise of the plate 6 and of the cylinder 2 is then controlled by turning the motor 9 in the opposite direction. The pressure of the liquid contained in the chamber 1, completely closed, increases as soon as the rise of the cylinder 2 begins and causes the opening of the valve 5 and the distribution of the product by this valve.

It should be noted that the assembly formed by the frame 8 and the device D can be movable, using one or more electric motors and suitable guide means, in two directions X, Y not shown, located in a horizontal plane, so that the distribution through the valve 5 can take place along any desired line or surface.

This makes it possible to carry out either a point deposition, or a deposition along a line or on a surface of any shape.

It should be noted that the distribution of the product can be controlled by adjusting the ascent speed of the cylinder 2 and of the plate 6 controlled by the motor 9 and the screw 10.

In the case where it is desired to carry out a metered withdrawal of several products, followed by a mixture, and a distribution of this mixture, the operations are as follows.

A first product is pumped, dosed in the chamber 1 as explained above but is not dispensed. In other words, the cylinder 2 will remain in the position it occupies at the end of aspiration of the first product, for example the position illustrated in FIG. 1.

The shutter 17 is then rotated so as to bring the hole 18 in alignment with another channel corresponding to another product we want to take a dose of. The rotation of the shutter 17 caused the closure of the channel used for the previous sampling.

Then the descent of the cylinder 2 is controlled by the motor 9 and the screw 10, by a distance corresponding to the volume which it is desired to take for this second product.

When this pumping-dosing operation is completed on the second product, the operation described for a third product is repeated. All the components of the desired mixture are thus pumped precisely in a sequential manner. The maximum possible volume for the sample taken corresponds to the maximum volume of chamber 1.

It should be noted that the presence of non-return valves 15 at the lower end of the sampling channels makes it possible to avoid, during the rotation of the selection barrel 19, any contamination of the products relative to the other.

When the pumping and metering operations of the various components of the mixture are completed, the barrel 19 and the shutter 17 are rotated, by the motor 23, until the hole 18 corresponds to the channel 16 corresponding to the chamber mixture. The position of the shutter 17 corresponds to that illustrated in FIG. 4.

The mixing chamber constituted by a compartment 28 in the case of FIG. 7, or by the independent tank M in the case of FIG. 1, has a sufficient volume, at least equal to the maximum possible volume of the chamber 1.

The rise of the cylinder 2 is then controlled by the motor 9 so as to discharge the mixture of products into the mixing chamber. This is possible because the valve 5 is calibrated, in the direction of opening, to a value greater than the pressure necessary to pass the products from chamber 1 to the mixing chamber such as 28. As a guide, the valve 5 is tared at the opening to 400 grams force (4 N).

The mixing chamber 28 therefore fills with the entire volume of the discharged products.

When this operation is finished, the mixture is sucked back into the chamber 1 by a downward movement of the cylinder 2; then this mixture is pushed back into the mixing chamber 28 by raising the cylinder 2.

These suction and discharge operations between the chamber 1 and the mixing chamber 28 are repeated a certain number of times to ensure good homogenization of the mixture, the number of aspirations and discharges depending on the nature of the products to be mixed.

When the mixing operation back and forth from the chamber 1 to the mixing chamber 28 is complete, the entire mixture is sucked back into chamber 1. The barrel 19 and the shutter 17 are put in place. rotation by the motor 23 until it reaches an intermediate position such as that illustrated in FIG. 6, for which the hole 18 is located between two channel orifices. Chamber 1 is then sealed.

The rise of the cylinder 2 is then controlled by the motor 9 and the screw 10, which causes the distribution of the mixture through the valve 5 which opens under the pressure increase.

The device therefore makes it possible to produce, in addition to a volumetric pumping-metering and a controlled distribution, a homogeneous mixture of different products before distributing them.

It is clear that it is possible to prepare a quantity of product greater than the exact quantity to be dispensed, the excess product then being able to be stored via the mixing chamber 28.

All the products can be either in the open air, that is to say at atmospheric pressure, or under overpressure, and even under inert gas. If the products are pressurized in the tanks, the calibration of the non-return valves 15 and 5 should be adjusted accordingly.

As a variant, the non-return valves 15 could be omitted in favor of an additional barrel, which would serve, by slight rotation, to close the end orifices of the channels such as 13 of the piston, during the selection of the product by rotation of the selection barrel 19.

Alternatively also, the chamber 1, instead of being delimited by a cylinder 2 and a piston 11, could be delimited by a bellows-membrane whose upper end would be closed by a sort of fixed plate, and whose lower part could be approached or away from the top plate to vary the internal volume of the bellows.

Many applications are possible, for example for the preparation of liquid mixtures, emulsions, pastes, in synthetic chemistry, in formulation chemistry. This device can also be used for the manufacture of liquid or pasty products, or as an instrumentation accessory, or intervene in chemical engineering.

The device can be used for the production of automatic formulators, or for personalized distribution in hair cosmetics, or in the pharmaceutical, food, or paint, make-up cosmetics, household products.

The device can also be used for technical distribution in a hair salon or in hospitals.

In summary, the device of the invention makes it possible to produce automatic machines, in particular for formulation laboratories in general, for carrying out automatic distributions of personalized mixtures (at hairdressers for example), as well as for manufacturing activities.

Claims (14)

1. Metering device for taking up a volume of liquid, pasty, or powdered product from at least two containers (27, 27a-27d), and then for dispensing all or part of the volume taken up, comprising:

   - a chamber (1) of variable volume, delimited by the internal wall of a cylinder (2) and by the end of a piston (11), it being possible for the cylinder (2) and the piston (11) to have a movement of relative displacement in terms of translation in a direction parallel to the axis of the cylinder (2), the said piston being traversed by at least two ducts (13, 13a - 13d) substantially parallel to the axis of the cylinder, each duct, via its opposite end to the chamber (1), being connected to a container (27, 27a-27d),

   - a selection means (S) in the form of a rotary shut-off (17) pierced with a passage hole (18) and placed at the internal end of the piston (11) and which, depending on the position into which it is turned either brings the chamber (1) into communication, via the passage hole (18), with the duct connected to the container (R, 27, 27a-27d) from which it is desired to draw off a volume of product, while at the same time shutting off the other ducts, or shuts off all the ducts connected to the containers (27, 27a-27d),

   - means (9, 10) for controlling the variations in volume of the chamber (1) making it possible to draw in or to discharge depending on whether the chamber (1) is increasing or decreasing in volume,

   - and a dispensing orifice (4) in the wall of the chamber (1), the said orifice being associated with means which automatically close the orifice (4) outside dispensing periods.
2. Device according to Claim 1, characterized in that the piston (11) is fixed with respect to a supporting structure (8) whereas the control means ensure a reciprocating translational displacement of the cylinder (2) along its axis.
3. Device according to either of Claims 1 and 2, characterized in that the shut-off (17) constitutes the bottom of a cylindrical barrel (19) in which the piston (11) is engaged, the said barrel (19) having an axial length which is greater than that of the cylinder (2) so as to keep part of it (20) outside the cylinder when the barrel is totally driven into the cylinder.
4. Device according to Claim 3, characterized in that the outer part (20) of the barrel (19) includes means (22) for rotationally driving this barrel about the geometric axis of the cylinder, the piston (11) having a part which remains outside the barrel.
5. Device according to Claim 4, characterized in that the drive means comprise a ring gear (22) the mid-plane of which is orthogonal to the axis of the barrel (19), this ring gear (22) being capable of interacting with a pinion (25) driven by an electric motor (23), particularly a stepper motor.
6. Device according to Claim 3, characterized in that the shut-off (17) and the barrel (19) are centred and fixed on the end of a rod (21) mounted so that it can rotate in an axial bore of the piston (11).
7. Device according to one of Claims 1 to 6, characterized in that the piston (11) includes in addition to parallel ducts (13, 13a-13d, 16) distributed about its axis and connected to a different liquid container (R, 27, 27a-27d), an additional duct (16) connected to a mixing chamber (M, 28).
8. Device according to Claim 7, characterized in that each duct (13, 13a-13d) of the piston connected to a product container is equipped, at its end adjacent to the chamber (1), with a non-return valve (15), whereas the duct (16) connected to the mixing chamber (M, 28) is not provided with such a non-return valve.
9. Device according to one of Claims 1 to 8, characterized in that the means (C) for shutting off the dispensing orifice (4) consists of a valve (5) preloaded to a sufficient level, so as to open only for a pressure which greatly exceeds that necessary for causing the product or products to pass into the mixing chamber (M, 28).
10. Device according to Claim 2, characterized in that the control for the translational displacement of the cylinder (2) is provided by an electric motor (9), particularly a stepper motor, controlling a screw (10) which acts on a nut linked with the cylinder.
11. Device according to Claim 7, characterized in that the device comprises a multi-compartment container (26), each compartment (27, 27a-27d, 28) being connected to a duct (13, 13a-13d, 16) of the piston (11), all the compartments (27, 27a-27d) except for one (28) being assigned to a product, the last one (28) of these compartments constituting the mixing chamber, this multi-compartment container (26) being fixed directly above the outer face of the piston (11), where the ducts emerge.
12. Device according to Claim 11, characterized in that a thermostat with a heating element is provided, right within (30) the container, and is incorporated into the system.
13. Device according to Claim 7, characterized in that the different products are contained in containers (R) which are separate from one another, each container (R) being connected by a connection tube, which is as small as possible, to the end of a duct (13) of the piston (11), a container (M), which initially is not provided with product, acting as a mixing chamber and also being connected to the additional duct (16) of the piston.
14. Method for mixing the various products, characterized in that a device according to one of Claims 1 to 13 is used and in that the volumes of the different products which are required for producing the mixture are taken up sequentially into the chamber (1) of variable volume, and that all these taken-up products are discharged into a mixing chamber (28, M), and that, by successive reciprocating movements, the mixture is drawn in and discharged from the mixing chamber (28, M) towards the chamber (1) of variable volume, and vice versa, so as to homogenize the mixture.

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