EP0696480B1 - Membrane pump - Google Patents

Abstract

The pump has a body (1) with a inlet (11) discharging into a measuring chamber (12). The measuring chamber has an inlet valve (20) and a piston (3) with a plunger (30) which has an axial jet (31). The jet enlarges in its lower part into a corolla (32) receiving a flexible membrane lining (4). The jet internal channel (31a) leads to an outlet valve (40). The outlet valve is part of a single deformable piece forming the membrane constituted from a lower U collar (42), assembled on the corolla of the plunger. At the top is fastened an external cylindrical sealing skirt (43) and the piston back, in its rest position, extends an annular flange (44) at the membrane junction on the body. At the upper narrow end of the conical outlet valve a cut-out (4) in the membrane is edged by a lip opening onto the outlet orifice.

Description

The present invention relates to a metering pump and, more specifically, a miniature dosing pump used vertically.

There are already (FR-A-2643 338) such miniature dosing pumps, adaptable to a container and which include a body provided with a socket associated with an intake valve, and a plunger returned to the rest position by an elastic return member but provided with a hollow rod or axial nozzle projecting from said body to serve as both a presser rod and an ejection tube product, its internal channel being associated with an exhaust valve; generally the valve of the intake valve is free but that of the exhaust valve is tared or returned to the closed position by an elastic organ. By means of a seal, body and piston delimit a metering chamber; it contains initially a certain volume of air, which will most often be exhausted for priming by mechanical opening of the exhaust valve.

The elastic members are often in the form of springs metal which cannot always be brought into contact with the product and also cannot undergo the same reprocessing operations than the other parts of the pump during possible recycling.

The invention aims to provide a metering pump on simple structure, free from this difficulty, and safe operation.

• extérieurement une jupe sensiblement cylindrique d'étanchéité et de renvoi du piston en position de repos que prolonge une bride annulaire de jonction étanche sur le corps,
• intérieurement une valvule de forme générale conique ou mitrale dont l'extrémité supérieure étroite porte une découpe ouvrant un orifice d'éjection.

This object is achieved, according to the invention, by means of a pump of the type having a body provided with an outlet opening into a metering chamber, associated with a flap inlet valve and a plunger piston provided with an axial nozzle widening at its lower part into a corolla receiving a seal, its internal channel being associated with an exhaust valve valve, characterized in that said exhaust valve belongs to a single elastically deformable part forming this lining, consisting of a lower U-shaped ring, which is assembled on the corolla of the plunger and to which are attached upwards:

• externally a substantially cylindrical sealing and return skirt of the piston in the rest position extended by an annular sealing junction flange on the body,
• internally a valve of generally conical or mitral shape, the narrow upper end of which carries a cutout opening an ejection orifice.

According to another characteristic, the pump also has a collar that closes the upper opening of the body with a veil bearing a guide and retaining bearing forming a high stop for a shoulder created by the corolla of the diver. Preferably, this flange carries an external lateral connection belt with the container. More preferably, the outer annular flange of the trim is taken between the flange and the upper edge of the body.

The skirt, the height of which is advantageously of the same order that the stroke of the piston until it comes to the bottom stop is maintained as soon as its rest position under sufficient tension.

According to an advantageous characteristic, to allow the exhaust valve to withstand sufficient pressure, the lip of the cut cooperates with a circular central core for closing off the ejection orifice on which it comes into clamping. According to another characteristic, the exhaust valve cooperates with a spacer protruding from the bottom of the metering chamber and drawn so as to engage in the valve to spread the lip at the end of low stroke of the piston, just before the stop, providing a passage between the metering chamber and the ejection orifice, thus causes forced opening.

Preferably, the core or seat consists of a lug axial placed at the bottom of the nozzle, the cavity inside the corolla communicating with the channel thereof by at least one orifice pierced laterally at the root of the lug. Advantageously, the retractor is an axial sleeve capable of passing around and along said lug, the passage being formed of through openings which are possibly placed on the upper edge of said sleeve, in the form of slots.

According to another advantageous characteristic, the valve intake includes a semi-rigid shutter housed in a cavity of corresponding section of the metering chamber, supporting the spacer but connected to a post freely engaged in the taken where it is retained by an internal constriction.

The trim, made in one piece, ensures jointly the functions of exhaust valve, seal seal and piston return member at the top of the metering chamber, the spacer guaranteeing the mechanical opening of the exhaust valve.

• figure 1, en coupe longitudinale, un premier mode de réalisation de la pompe de l'invention;
• figure 2, en coupe avec vues 2a à 2d, différentes phases du fonctionnement d'un deuxième mode de réalisation de la pompe de l'invention.

The invention will be explained on reading the following description of two advantageous examples, accompanied by the appended drawings, which represent:

• Figure 1, in longitudinal section, a first embodiment of the pump of the invention;
• Figure 2, in section with views 2a to 2d, different phases of the operation of a second embodiment of the pump of the invention.

The pump shown in FIG. 1 comprises a body 1 which ends in its upper part with a flat upper rim 10 . The body 1 is provided with a socket 11 associated with a lower intake valve 2 and it receives a piston 3 . By means of a gasket 4 , creating an upper exhaust valve 5 , the piston 3 delimits inside the body 1 , between the exhaust valve 5 and the intake valve 2 , a metering chamber 12 .

The outlet 11 opens into the chamber 12 through an inlet orifice 11a . It allows, directly or through an auxiliary tube, the withdrawal of the product to be dispensed from a container or bottle (not shown) on which the pump is intended to be mounted.

The piston 3 comprises a plunger 30 with axial nozzle 31 projecting from the body 1 and in its lower part on the one hand a peripheral corolla 32 creating an upper shoulder 32a , on the other hand a central lug 33 serving as a seat for the exhaust valve, the corolla 32 delimiting around it a cavity 34 which communicates with the axial internal channel 31a of the nozzle 31 by at least one lateral orifice 35 formed at the root of the lug 33 .

The upper end of the nozzle 31 will, for example, be capped with a head 6 carrying a dispensing nozzle.

The exhaust valve 5 belongs to the packing 4 . This part consists of an axial valve 40 , substantially frustoconical, the upper end of which is provided with a cutout 41 bordered by a lip generating an ejection orifice and the lower edge attached to a ring 42 , in U d assembly on the corolla, ring itself connected to a thin skirt or substantially cylindrical return membrane 43 of the piston 3 , which is extended upwards by an annular flange 44 ensuring its tight junction with the body 1 . The lining 4 is made with an elastomeric material which makes its skirt extensible. The central lug 33 closes the ejection orifice of the valve 40 , putting its lip in tightening.

The pump of the example further comprises a flange 7 for closing and fixing on a container or a bottle (not shown). The flange 7 consists of an internal axial bearing 70 connected to a belt 71 . The belt 71 is formed of an external lateral skirt with screws or interlocking with a veil 72 .

The lining 4 is taken between the flat upper edge 10 of the body 1 and the collar; it is preferably fixed by mutual interlocking of rods 73 , its web 72 then pinching the flange 44 sealingly, a groove 74 leaving however on its upper face a passage between the interior of the container and the pump then the atmosphere along the bearing 70 .

The lower edge of the bearing 70 forms an upper stop for the shoulder 32a of the plunger 30 , the corolla 32 of which thus closes the opening of the groove 74 in the rest position, then also leaving the return skirt 43 of the lining 4 under tension. sufficient, corresponding to an elongation of the order of 30%.

The inlet valve 2 has a ball valve 20 resting on its seat in a cavity 13 formed in the lower part of the chamber 12 and a cage formed by a washer 21 retained for example by lateral friction against the wall of the chamber 12 . This cage leaves the ball a freedom of movement such that it can clear the inlet 11a to allow the passage of the product. The washer 21 further carries in its upper part a central sleeve 22 ; the latter projects upwards inside the metering chamber 12 and comprises an internal space 22a opening at its upper end into this chamber. The washer 21 is provided with perforations 23 which allow the metering chamber 12 to communicate with the cavity 13 and the sleeve 22 with through openings 24 and / or 25 towards the space 22a .

The sleeve 22 is intended to engage in the valve 40 with a slight clearance around the lug 33 , its upper edge coming apart the lip of the cutout 41 when the piston comes into low stop for an elongation of the skirt of the 'around 100%; it will thus cause the forced opening of the ejection orifice. Its height is therefore determined as a function of that of the valve.

During a rise of the piston, the intake valve 20 lifts under the effect of a vacuum in the metering chamber 12 to then fall back below that of its weight then, during a descent, remain pressed by the product pressure in this chamber, while the exhaust valve 40 will open under the effect of this same pressure to finally close under the action of its own elasticity. If however said internal pressure remains insufficient due to the presence of a compressible fluid in the chamber 12 , in particular air during a first use, the mechanical opening of the valve 40 will allow this fluid to be evacuated.

The pump of FIG. 2 represents an embodiment of the invention differing mainly by its intake valve. It is also a ventless pump, which will be mounted on a container without air intake, such as a container with flexible internal pocket. Approved parts have the same references and will not be described again.

In view 2a , the pump is at rest.

Its inlet valve 8 has a tapered shutter valve 80 , made of plastomeric or elastomeric material, normally resting in the low closed position in a cavity 13 of corresponding profile. The shutter 80 is capable of being lifted but it is connected downwards to a stud 81 engaged in the socket 11 where the throttle 11b retains it; in this example, the post consists of two flexible tabs.

The intake valve 8 here again comprises, in its upper part, a central sleeve 82 which projects upwards and has an internal space 82a where the lug 33 can be received; it is intended to engage in the valve 40 to cause the mechanical opening of the ejection orifice. Here, the sleeve 82 is integral with the shutter 80 and its upper edge is crenellated.

In view 2b , the depression of the head causes the plunger 30 to descend and, by pressing its corolla 32 on the assembly ring 42 of the lining 4 , the downward elongation of the skirt 43 which thins especially. The intake valve 8 is then in the low position corresponding to the closing of the intake orifice 11a .

This movement therefore normally causes in chamber 12 a rapid increase in pressure which forces the lip of the valve 40 to move away from the lug 33 , opening the ejection orifice as shown in the figure.

At the end of the race, in the position shown in view 2c , the ring 42 coming into abutment in the bottom of the metering chamber 12 , the valve 40 engages on the socket 82 of the shutter 80 , the lug 33 penetrating into its internal space 82a .

The thrust of the merlons 83 of the socket 82 deforms the upper part of the valve 40 at the level of its ejection orifice, freeing around the lug 33 , towards the cavity 34 , an annular passage which the slots 84 put in communication with room 12 . During a first use, if the chamber 12 contains air, it is only then that this is evacuated by the cavity 34 , the orifice 35 and the nozzle channel 31 .

In view 2d , the head 6 is gradually released: the skirt 43 therefore recalls the piston 3 upwards to its initial position.

The upward stroke of the piston 3 and the depression created by it in the metering chamber 12 cause the inlet valve 80 to open , but the tenon 81 stops against the throttle 11b forces it to disengage from the valve 40 so that the ejection orifice closes on the lug 33 and the product is sucked through the socket 11 .

When the pump, filled, is again in the position of view 2a , the pressure balance is reached by reducing the internal volume of the container and the valve 80 drops back into its closed position.

The pump is then ready for a new product distribution. With the pump of FIG. 1, this result would be achieved by entering air through the vent 74 .

Claims (10)

1. A miniature metering pump of the type possessing a body (1) provided with an inlet (11) which opens out into a metering chamber (12), which is associated both with an inlet valve (2, 8) having a valve member (20), and with a piston (3) having a plunger (30) provided with an axial nozzle (31) and flared at its bottom end to form a hood (32) which receives a sealing gasket (4), its internal channel (31a) being associated with an outlet valve (5) having a valve member (40), the pump being characterized in that said outlet valve member (40) forms a portion of a single elastically deformable part which constitutes said gasket (4), which is shaped to have a bottom U-shaped ring (42) assembled round the hood (32) of the plunger (30), and which is upwardly connected:

   on the outside to a substantially cylindrical skirt (43) for sealing and for returning the piston (3) to its rest position, which skirt runs on from an annular flange (44) for providing sealed connection with the body (1); and

   on the inside to a folded valve member (40) that is generally conical or mitral-valve shaped, with a narrow top end having a cutout (41) surrounded by a lip that opens to provide an outlet orifice.
2. A pump according to claim 1, characterized in that it also possesses a collar (7) which closes the top opening of the body (1) by means of a web (72) carrying a guiding and retaining bearing (70) forming a top abutment for the shoulder (32a) created by the hood (32) on the plunger (30).
3. A pump according to claim 2, characterized in that said collar (7) carries an outside lateral belt (71) for connection to the receptacle.
4. A pump according to claim 2 or 3, characterized in that the annular flange (44) of the gasket (4) is engaged between the collar (7) and the top rim (10) of the body (1).
5. A pump according to any preceding claim, characterized in that the skirt (43) which is advantageously of substantially the same height as the stroke of the piston (3) coming into bottom abutment, is held even in the rest position under sufficient tension.
6. A pump according to any preceding claim, characterized in that the lip of the cutout (41) co-operates with a circular central core for closing the outlet orifice and onto which it clamps.
7. A pump according to claim 6, characterized in that the core is constituted by an axial stud (33) placed at the bottom end of the nozzle (31), the cavity inside the hood (32) communicating with the channel (31a) thereof via at least one orifice pierced laterally at the root of the stud.
8. A pump according to any preceding claim, characterized in that the outlet valve (5) co-operates with a spreader projecting from the bottom portion of the metering chamber (12) and designed to engage inside the fold valve (40) to lift off its lip at the end of the downstroke of the piston (3) immediately before the piston comes into abutment, thereby providing a passage between the metering chamber (12) and the outlet orifice, which it thus opens by force.
9. A pump according to claims 7 and 8, characterized in that the spreader is an axial chimney (22/82) capable of passing around and along said stud (33), with the passage being formed by through openings (24, 25) optionally placed at the top edge of said chimney (82), in the form of crenellations (84).
10. A pump according to claim 8 or 9, characterized in that the inlet valve (20) includes a semi-rigid valve member (80) received in a cavity of corresponding section in the metering chamber (12), the valve member supporting the spreader but being also connected to a tenon (81) that is freely engaged in the inlet (11) where it is retained by an internal narrowing (11b).

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