EP0557194B1 - Dispenser with electric motor - Google Patents

Description

To precisely deliver sufficiently continuous, preferably adjustable, liquid flows, numerous types of metering pumps have been designed driven by electric motors, in particular piston pumps of rectilinear stroke, generally driven by a connecting rod in a quasi-movement. sinusoidal, away from the law and the games of the transmission.

It also happens that one only wishes to debit under the effect of an external command, in particular with an electric motor, a given quantity of a fluid such as disinfectant, perfume, etc .; the objective is generally to operate in a brief but precise and regular manner, in particular to obtain a frank projection of the product, and in particular its fine spraying in one or more pulses. We then proposed all kinds of transmissions, eccentrics or more complex cams ... and even exhausts and triggers allowing to obtain a less progressive law of movement than the simple sinusoid therefore a drier control and a shorter jet under higher pressure .

In this context, we have considered the use of actuators, often equipped with a lever which allows in particular to return and reduce the stroke by increasing the available force. They can be simple electromagnets returned to the rest position by a spring; However, this option has the drawback of requiring an increased pushing force without guaranteeing a fairly rapid return to the rest position. It is therefore possible to prefer alternative actuators of well-known types similar in particular to the vibrators which are fitted in particular to electric razors. All can be supplied from a continuous source which makes them independent, this using electronically controlled choppers providing a staircase signal whose rectangular or only abrupt shape will correspond well to the energetic impulse sought and whose levels and the frequency will be easy to adjust to change the flow; operation is advantageously controlled by a time or pulse count relay.

In most cases, the devices thus designed will be capable of using refills and will in particular use for this purpose a housing receiving one of the well-known packages equipped with a miniature pump used by the perfume or cosmetic industry, medicines, insecticides ... This pump is generally provided with a piston rod which acts as a nozzle feeding its dispensing head; axially mounted, generally fixed by a flange, on the opening of the container intended to enclose the product, it therefore allows for example to seal in a leaktight and aseptic manner a bottle of medicament. It can be of any conventional type used in large series on these miniature distributors, and usually of a so-called precompression model, frequently employing a ball inlet valve and an exhaust valve with sleeve recalled by a spring, the construction of which is intended to allow the fluid to be released only under minimum pressure, and improves spraying.

These devices often take advantage of the fact that the pumps which equip them are controlled by a pusher and have their own return spring, which keeps them at rest in a sealed position, in order to employ only a single-action mechanism enabling the high position; but here again it seems preferable to join the pump and the mechanism. A device for dispensing liquid products associating on a single housing an interchangeable reservoir packaging equipped with an axial miniature pump provided with a piston rod serving as a nozzle towards its dispensing head, and an electrical control mechanism is known in particular from document DE -A-2 736 532.

A major use is that of easily transportable devices, usable in particular for dispersing over a very short period a sufficiently precise, albeit minimal, dose of a product: for example, we may wish to allow a patient to inhale over time. an inspiration a dose of an airway medication. The volume of the reservoir required will therefore not exceed a few milliliters, which will make it possible to have a compact and light assembly, holding in the hand and capable of constituting a pocket or bag device.

In fact, the solutions proposed only give imperfect results: even with precompression pumps which are in general use, one observes, going up in frequency, and from 20 Hz, irregularities then losses of flow, uneven spraying and even deterioration of the pumps. The actuators in particular do not give the expected results.

The object of the invention is therefore to propose a device of this kind, associating a suitable motor mechanism with a packaging provided with a miniaturized pump of an external volume which may drop below a cubic centimeter, assembled on a container of appropriate volume, this device combining great simplicity, low cost, small footprint and sufficient autonomy but being free from the drawbacks mentioned.

To this end, it proposes using a pump with positive intake and exhaust valve control, that is to say caused directly by the piston and not by equilibrium with the hydraulic forces, and typically a pump in which the piston itself acts directly as a drawer; better, this pump will be with a deformable body, or more precisely with a radially elastic body, in particular with a multi-lobed cross section, such as those described by patent publication EP-A-0 330 530: there is then a spectacular improvement in operation.

As an explanation, it is to be thought that the desired operating speeds, although moderate, prohibit reasoning in purely static terms as we used to do, and we encountered until then phenomena of inertia such as panic valves, turbulence, cavitations and water hammer. However, the pumps proposed here are distinguished by a well-determined pumping volume thanks to the positive control of their valves and to the simplicity of their structure; but at the same time their elasticity in practice exclusively radial attenuates the phenomena of overpressure. Added to this is good ease of priming and low friction, possibility of stopping in any position on the models without air intake and especially to work on a low stroke with acceptable precision, in particular, insofar as their valves cooperate with lateral orifices, on a partial stroke and by adjusting the respective durations of the operating phases by means of the positions of these orifices.

They thus cooperate in a particularly efficient manner with the various motorizations proposed so far: the pump remains capable of following the motor, over the whole of its stroke comprised between the full opening of the intake and the full opening of the exhaust up to at relatively high oscillation frequencies, up to 30 Hz in sinusoidal motion. An alternative actuator would make it possible to further increase speed but without any real benefit because the inertia of the parts imposes in practice a similar law, preventing in any event the pump from exactly following the law of current pulses and bringing its movement closer to a pseudo-sinusoidal oscillation; however it is in particular heavier and noisier.

Thus, in a preferred version, the pump will be driven by a rotary DC motor driving a cam, conveniently an eccentric, mounted directly at the end of the shaft and working without play in the direction of the pump; this solution is simple, compact, inexpensive, quieter and the distribution of efforts more favorable; it is easy to adjust the motor speed by changing its supply voltage. We can therefore easily adjust the flow rate, in a regular if not entirely linear manner: a 25 µl pump of nominal capacity operating at a frequency of 30 Hz then provides a flow rate close to 2 l / h, i.e. 0.5 ml / dry or, if preferred, finely pulverize a drop of product in one tenth of a second.

If the connection works in both directions, we obtain autonomous double action commands, compact and sufficiently powerful over the short stroke required, which incidentally allow the return spring of the pump to be eliminated; it can therefore be made free of any internal metal part.

The pump head, which can be of conventional structure, for example carrying a spray nozzle, or even be connected by a flexible conduit to an outlet nozzle mounted fixed on the housing if this does not result in a dead volume excessive, will conveniently serve to secure in translation the nozzle rod and the movable member of the engine mechanism.

• figure 1 : une coupe schématique d'un dispositif complet,
• figure 2 : une coupe selon II-II de la figure 1,
• figure 3 : une coupe d'un autre agencement général,
• figure 4 : une coupe selon IV-IV de la figure 3,
• figure 5 : un schéma de l'entraînement préféré,
• figure 6 : un détail selon VI-VI de la figure 5,
• figure 7 : une coupe-élévation d'une pompe avantageuse,
• figure 8 : une coupe selon VIII-VIII de la figure 7.

The invention will be illustrated below in the context of a triple example, with reference to the drawings, which show:

• FIG. 1 : a schematic section of a complete device,
• FIG. 2 : a section along II-II of FIG. 1 ,
• FIG. 3 : a section through another general arrangement,
• FIG. 4 : a section on IV-IV of FIG. 3 ,
• FIG. 5 : a diagram of the preferred training,
• FIG. 6 : a detail according to VI-VI of FIG. 5 ,
• FIG. 7 : a sectional elevation of an advantageous pump,
• Figure 8 : a section along VIII-VIII of Figure 7 .

In broad outline, the devices shown in FIGS. 1 to 6 are known but will, in accordance with the invention, be provided with a specific pump, an advantageous example of which will be shown in FIGS. 7 and 8 . They can be used, for example, to deliver specific, finely sprayed doses of an airway medication.

That of FIG. 1 comprises a sprayer made up of a container 1 , the opening of which receives a pump 2 held in place in a leaktight manner by a flange 3 . The latter allows the axial nozzle 4a to pass which serves as a rod for the piston 4 of the pump and itself carries a head 5 of which it supplies the spray nozzle 5a . The whole forms a homogeneous and sterile packaging.

This sprayer is introduced into a housing 6 conventionally formed of two interlocking half-shells, possibly articulated. As best shown in Figure 2 , it is retained there by the walls against stops such as ribs 6a ; simultaneously it is taken between their shoulders 6b and the floor 6c of the housing.

The housing 6 contains an actuator 7 comprising an armature 7a carrying a coil 7b and in front of the two poles 7c and 7d from which a lever 8 with a ferromagnetic core 9 can oscillate articulated on the housing by its axis 10 placed in the plane of symmetry of the frame.

The electromagnet of the actuator 7 is supplied by an electronic chopper 11 , from rechargeable batteries or accumulators 12 , under the control of a contactor 13 ; in order not to clutter the figure, the electrical connections have been omitted. In one to five tenths of a second for example, at a preset frequency capable of reaching and exceeding 20 Hz but preferably less than 40 Hz, the chopper will be able to deliver in response to any action on this contactor a series of pulses steep and brief more or less close.

At rest, in the position shown, the arm 8a of the lever is returned to the right by the set of two springs 14 ; as shown in Figure 2 , its arm 8b , at 90 ° and slightly offset from the median plane, carries a lug 8c , which thus moves on a short stroke, of the order of 3 mm for example, in a practically vertical direction.

The head 5 carries an ear 5b pierced with a hole 5c which laterally fits onto the lug 8c when the sprayer is placed on the housing. If the head 5 itself is firmly fixed on the nozzle, for example with hard friction or even by ultrasonic welding, and if the tolerances are well studied, it can be seen that the reduction lever 8 thus recalls the piston 4 of the pump towards the top, in the sealing position, independently of the action of the internal return spring of this piston; this latter spring can thus be eliminated.

The entire device will not be described more fully here since it employs only a mechanism well known to manufacturers of small motors, similar for example to various controls of electric shavers. There are many variations and one could be used depending on the race, size etc. solutions without angular gear, or with a movable core in translation and capable of directly attacking the pump head, or even with periodic control started by a switch.

FIG. 3 thus shows, under the same references, a version with a movable core carrying permanent magnets. Such an actuator mechanism among others can work without return springs similar to the springs 14 of the first version, which gives it an operating curve closer to that of the electrical impulse therefore steeper. Emitting alternating pulses adjustable in duration and period, the electronic control can then take care of stopping the core 9 in the low position; this will be retained by its permanent power supply in contact with the pole 7d of the electromagnet: if the mechanical control acts as well in traction as in compression on the pump head 5 , which accelerates the ascent of the piston, allowing the frequency of pump strokes to be increased if necessary, the electromagnet will also be able to maintain the seal at rest even in the absence of any piston return spring inside the pump .

As best shown in Figure 4 , the arm 8b of the lever is double, taking the form of a short fork which creates an open ring provided with two symmetrical lugs 8c , which creates an open ring. The ear 5b itself carries on each of its two faces a circular housing for one of the lugs, connected to a chamfered notch 5d . The packaging can thus be set up laterally after closing the case, through the opening 6d thereof, the edges of which will retain it elastically, the head 5 being brought horizontally into engagement between the two arms of the arm 8b . Interchangeability is improved.

FIG. 5 gives the diagram of a direct drive by a rotating motor. From the batteries 12 and via a relay 14 associated with a regulator of voltage 15 , the contactor 13 is used to power a DC motor 17 whose shaft 18 , perpendicular to the axis of the pump 2 , can thus rotate at speeds ranging for example from 500 to 2000 revolutions / min. Such motors can be provided with a stop in the high position.

As shown in FIG. 6 , the ear 5b of the head 5 of the packaging is pierced with an oblong orifice 5c which fits without appreciable vertical play on an eccentric 18a situated at the end of the shaft 18 , of similar to that shown in Figure 1 for the lug 8c of the lever 8 . The eccentric therefore plays the role of a double action cam, the head 5 and the distributor piston thus being driven in sinusoidal oscillation at the desired speed.

Certainly due to mechanical and hydraulic phenomena, this solution leads to a lighter, less brutal and more adaptable whole, blood visible loss of spraying qualities. This is why preference is given to it in the context of the invention.

FIG. 7 gives a particularly advantageous example of a dispenser using the principle of this invention. Its pump comprises a body 20 containing a piston 21 capable in its reciprocating movement of masking and then unmasking in turn the orifices of the intake channels 22 connecting it to the intake tube, and of exhaust 23 towards the nozzle 24 which it carries. Intended to be positively driven in each direction by the mechanism with which it will be associated, it is devoid of any internal spring, which can be advantageous with respect to the product used and can facilitate sorting operations with a view to recycling the constituents made of synthetic materials. It also has no air intake vent and is thus sealed in a sealed manner by a collar 25 on a pocket 26 intended to contain the product, inside a case 27.

The body 20 is virtually undeformable in the longitudinal direction, which guarantees precise control of the internal operation, the choice of the positions of the orifices allows the successive phases to be adjusted. However, FIG. 8 shows that the cross section of its middle part 20a of the body 20 is multi-lobed, which gives it sufficient transverse deformability to absorb water hammer at the envisaged speeds and yet a stiffness such that its walls follow the imposed rate.

The above pump or its possible variants will not be described here in more detail since it will suffice for the reader to refer to the abovementioned publication EP-A-0 330 530 to become aware of it.

Finally, it should be noted that the example of distributor given above is not incompatible with the use of a control mechanism without return in the high position such as that described in connection with FIG. 5 because it does not does not exist moment of direct communication possible between the tank and the exterior, neither by an exterior vent, nor by the interior of the pump, the orifices 22 and 23 not opening simultaneously towards the nozzle 24 .

Claims (10)

1. Dispenser device far liquid products, associating togther on a single housing an interchangeable pack having a reservoir equipped with a reciprocating metering pump, in particular a pack equipped with an axial miniature pump provided with a piston rod serving as small nozzle leading to its dispensing head, and an electrical operating mechanism, characterized in that said pump (2) is provided with positive drive for the intake and discharge valves.
2. Device according to claim 1, characterized in that the piston (4) itself, serving directly as slider inside the pump body (20), in turn masks and exposes its intake orifices (22) and discharge orifices (23).
3. Device according to claim 2, characterized in that the pump body possesses a part (20a) of non-circular section, and therefore elastically deformable in the radial direction.
4. Device according to,claim 3, characterized in that said deformable part has a polylobed (multifoil) cross-section.
5. Device according to one of claims 1 to 4, characterized in that the piston (4, 21) carries a head (5) which makes it integral with both the ascent and the descent of the double-acting movable element of the operating mechanism.
6. Device according to claim 5, characterized in that the mechanism does not have a stop position in the high position and that the pump is a pump without air intake.
7. Device according to claim 5, characterized in that the piston (4) is without any return spring.
8. Device according to one of claims 1 to 7, characterized in that the head (5) of the pump is operated by a cam (18a) from a rotating motor (17).
9. Device according: to claim 8, characterized in that the cam is an eccentric, situated directly at the end of the shaft of a direct current motor.
10. Device according to claim 5, characterized in that the operating mechanism comprises a double-acting alternating actuator (7), supplied via an electronic control (10) with an electric current having square-wave pulses adjusted in duration and period.

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