EP0821775B1 - Inlet valve assembly - Google Patents

Abstract

An inlet valve assembly built into a device for dispensing a fluid from a reservoir so that the reservoir is sealed off at least during the fluid dispensing phase. Said valve assembly includes a valve member (2) with a contact area for sealingly engaging a substantially frusto-conical valve seat (16) at least during said dispensing phase. The contact area of the valve member (2) forms part of a substantially frusto-conical surface (210). Said assembly is characterised in that the solid angle of the surface (210) is greater than that defined by the valve seat (16) so that the contact area is at least initially defined by a circle when the valve member is inoperative, and in that the frusto-conical surface (210) consists of a substantially flexible wall so that the initially circular contact area is resiliently bent into the shape of a cone frustum during the dispensing phase.

Description

The present invention relates to an intake valve assembly which can be integrate into a fluid or pasty product distribution device. In general, this kind of valve assembly is inserted in a pump body, in the lower part of the latter to fulfill the function of intake valve in order to isolate the pump chamber of the reservoir containing the product to be dispensed during the distribution.

A very common type of intake valve assembly uses a ball metallic as a dynamic member of the valve which comes into tight contact under the effect of the pressure exerted on the fluid in the pump chamber, with a valve seat which is generally an integral part of the pump body. The ball is held in a limited space by a valve holder which is generally inserted by force in the bottom of the pump body. The valve holder is formed with a passage which makes communicate the aforementioned limited space with the pump chamber itself. The ball is free to move in this limited space without being able to obstruct the passage Communication. It is only during the distribution phases, i.e. pressurizing of the fluid product, that the ball is pressed against its seat.

Although widely used in all kinds of distribution devices, even other than a pump, the ball however has certain drawbacks.

On a physical level, the ball is made of a material having a high density, in this case steel. The weight of the ball is therefore relatively large. In its dynamic behavior, when the distribution device is used to upside down, i.e. the valve seat at the top, the ball does not respond immediately under pressure and takes a while to gain a seat valve. Indeed, the pressure must be sufficient to overcome the weight of the ball. The difficulty that the ball encounters in moving up on its seat is all the more more increased by the fact that the ball has an advantageous geometry on the plane hydraulic. The surface quality of the metal ball and its shape offer only very little resistance to fluid.

On the other hand, ecologically, the ball constitutes a metallic element which prohibits recycling of the distribution device that incorporates it, unless it is dismantled prior. A current trend is towards the elimination of metallic elements in mainly plastic products as is the case with a pump.

In addition, the balls during their transport or assembly, collide, which which has the effect of damaging their surface and thus creating leaks.

On an economic level, the ball is an expensive part, because it is made in steel and must have a perfect sphericity. We have also noticed that many logs were lost during transport or handling, because of their elusive spherical shape.

There are other types of intake valve that do not use a ball as that dynamic organ. For example, some dispensing devices incorporate a valve in the form of an elastomer washer which is trapped in a space restricted. When the pressure increases in the distribution chamber of the device, the washer seals tightly on the intake port. The waterproof contact comes from the simple axial application of the washer on the intake port. So, to obtain a good seal, it is necessary that the pressure exerted on the washer is large enough.

In most prior art intake valves, a valve member (ball, washer, etc.) is confined in a volume restricted by a valve holder. In in all cases, the valve member is not linked to any part and can float in the volume associated with it.

Document WO 95/01226 defines a valve, the valve member of which has a frustoconical section coming into contact with a frustoconical valve seat. The sealing contact is made on a frustoconical surface because the valve member and the seat define the same solid angle.

The object of the present invention is to remedy the drawbacks of the prior art aforementioned by defining a set of intake valve capable of making a contact waterproofing quickly and of very good quality. The valve member must respond immediately by plugging the intake port at the start of the distribution. The valve member must also be able to return to its valve seat. in all cases, that is to say both when holding the device to the place, upside down, or lying. Another object of the invention is to be able to use a classic valve holder normally adapted to receive a ball. This element being mass produced at low cost, the price of the set will be lower. The organ of valve which replaces the ball must also be able to be manufactured at a cost less than that of a ball, while providing an improved seal.

The valve assembly of the invention must have a seal whose quality improves with increasing pressure in the pump chamber.

To do this, the present invention relates to a valve assembly inlet integrated into a fluid dispenser contained in a reservoir for isolating a pumping chamber from said reservoir at least during a distribution phase of said product corresponding to an increase in pressure in said pumping chamber, said valve assembly comprising a valve member having a contact area coming into leaktight contact with a valve seat substantially frustoconical shape at least during said distribution phase, the area of contact of the valve member forming part of a substantially shaped surface frustoconical, characterized in that the solid angle of the frustoconical surface is greater than that defined by the valve seat so that the contact area is at least first defined by a circle when the valve member is at rest, and in that the surface frustoconical is formed by a substantially flexible wall, so that the area of initially circular contact extends to a truncated cone by elastic deformation during of the distribution phase. The valve seat of the invention is typically that of a ball valve. It is formed by the mouth of the intake channel which is part integral with the pump body. The valve member, meanwhile, is very different from a ball. Because the truncated cones defined by the seat and the valve member are different, an annular contact is created. At rest, when the device is held right with the seat down, this annular contact exists. It is however very different from that of a ball. Indeed, contact with a ball is of the circle-tangent type. so that contact with the valve member according to the invention creates a frustoconical volume in point between the seat and the frustoconical surface. The gap between the seat and the surface tapered is so weak that fluid can accumulate there by capillary action on a fairly large distance. This accumulated fluid promotes the maintenance of the valve member on his seat by increasing their cohesion. This is not the case for a ball where only a very small amount of liquid can be accumulated by capillary action. The increase in surface tension obtained with the valve member according to the invention comes directly from the difference in solid angle between the surface frustoconical and the valve seat. This increased surface tension increases significantly the quality of the seal, especially at rest, where the fluid retained by capillarity plays the role of fluid plug.

The annular sealing contact which exists when the device is at rest is transforms into frustoconical contact during the distribution phase. When the pressure increases in the distribution chamber of the device, a force is exerted on the flexible wall which has the effect of deforming it by pressing it against the valve seat. The higher the pressure, the larger the contact area. The tightness increases so with the pressure. In addition, due to the difference in solid angle and the capacity deformation, the contact at the level of the original annular contact zone is made more supported. The elasticity of the wall increases the tightness by exerting a no longer axial, but radial force. The elasticity thus makes it possible to transform a pressure exerted axially in a reaction force which acts radially.

Advantageously, the valve member comprises a corolla extending towards the outside in a frustoconical manner, of which a frustoconical outer wall defines said frustoconical surface. Thus, the pressure which is exerted on the corolla tends to deform it outwards and presses the tapered surface even more against the seat of valve, particularly at its largest diameter corresponding to the area original ring contact. The elasticity of the corolla associated with the pressure which stresses radially outwards make it possible to synergistically improve the seal of the valve.

According to one characteristic, the valve member comprises a rod having a lower end, the corolla being formed at said lower end. The organ of flap is in the form of a mushroom or an inverted umbrella. The concave annular shape defined by the outside of the corolla has good fluid grip characteristic, so that the valve member responds so instantaneous to the flow of fluid which is created at the start of the dispensing phase. Moreover, as the valve member is made of plastic, it offers only a very low inertial resistance.

According to another characteristic, the valve member is limited in displacement by a valve holder between a closed position and a suction position. The valve holder preferably be a conventional valve holder normally adapted to receive a ball.

Advantageously, the upper end of the rod is engaged in the passage of the valve holder. This keeps the valve member always substantially in the axis, because the rod cannot disengage from the passage.

On the other hand, the corolla includes a cylindrical end portion in the extension of the frustoconical wall. This cylindrical part fulfills a double role. First, it protects the frustoconical surface, and more particularly the area of larger diameter which corresponds to the original annular contact area. Secondly, this cylindrical part can serve as a sliding pad with its upper surface at the outlet of the dispensing bowl to obtain an orientation of the valve member.

Advantageously, the rod comprises two cylindrical sections of diameters different connected by a transition surface. The transition surface serves as a stop for the valve member in the suction position. Preferably, the valve holder defines abutment means for the valve member in the contact suction position simultaneous with an outer end edge of the cylindrical end portion and the transition surface, so as to keep the valve member in the axis in position suction.

The invention will now be described in more detail with reference to the accompanying drawings, giving by way of nonlimiting example an embodiment of the present invention.

• la figure 1 est une vue en coupe d'un ensemble de clapet d'admission selon l'invention, intégré dans un corps de pompe, l'organe de clapet étant dans une position de repos;
• la figure 2 est une vue en coupe de l'ensemble de clapet de la figure 1 avec l'organe de clapet en position de fermeture,
• la figure 3 est une vue en coupe de l'ensemble de clapet des figures 1 et 2 avec l'organe de clapet en position d'aspiration.

In the drawings:

• Figure 1 is a sectional view of an intake valve assembly according to the invention, integrated in a pump body, the valve member being in a rest position;
• FIG. 2 is a sectional view of the valve assembly of FIG. 1 with the valve member in the closed position,
• Figure 3 is a sectional view of the valve assembly of Figures 1 and 2 with the valve member in the suction position.

Referring indifferently to Figures 1 to 3, the structure of the assembly of intake valve will be explained below. The valve assembly is integrated in a pump body 1 at its bottom. The pump body has only been shown partially in the figures. The pump body at the valve assembly intake includes an upper cylindrical body and a lower sleeve 11 in which a dip tube can be force fitted. At the junction of the sleeve 11 and cylindrical body 12, the pump body has a channel 15. The intake channel 15 is extended upwards by a part frustoconical 16 which forms a valve seat. The valve seat 16 forms a recess frustoconical in the bottom of the cylindrical body 12. Referring to Figure 1, we see that the cylindrical body 12 has a smaller diameter lower part connected to the upper part of the cylindrical body 12 by a frustoconical chamfer 13. This narrowing of the inner section of the cylindrical body 12 serves for the fitting to force of a valve holder generally designated by 3. The bottom of the body cylindrical 12 is also provided with an annular groove 14 which extends concentrically with the valve seat 16. This groove 14 serves to minimize the material shrinkage phenomenon after cooling, because the pump body is conventionally made of plastic material.

The pump body which has just been described is a conventional pump body which can be used in any dispensing device such as a pump. The valve seat 16 is particularly well suited for receiving a valve member in the form of a ball. The ball in the closed position is applied from tightly on the frustoconical valve seat 16. Similarly, the increase in the thickness of the wall of the cylindrical part 12 which causes a narrowing of its internal diameter is conventionally adapted to receive a valve holder which defines a valve chamber in which the valve member is trapped. Of course, another pump body can be used with the present invention without thereby get out of its frame. In the pump body used, the valve seat is part integral with the pump body, but it can also be envisaged to form a seat valve in an attached part in the pump body.

The valve holder 3 used in the embodiment described is a valve holder classic adapted to receive a ball. The valve holder comprises a crown 31 of which the outer periphery is in close engagement with the inner wall of the pump body in its lower diameter portion. The crown 31 is extended upwards by a tapered transient part 32 which ends in a ring 33. The ring 33 has a central passage or hole 34 which communicates the valve chamber 26 with the distribution chamber of the device. Internally, the crown 31 and the frusto-conical part 32 are provided with several lamellae 35 which extend from the bottom of the cylindrical body 12 to the central hole 34. In the embodiment shown, there are 4 of these slats 34. As will be seen below, these strips are used for the passage of the fluid when the valve member is in its position suction.

According to the invention, the valve member designated as a whole by 2 is not a ball. but is in the form of an elongated member terminated at its end lower by a frustoconical corolla 21. The corolla 21 is fixed at the end bottom of a rod having two different sections 23 and 24 connected by a frustoconical transition surface 25. In any situation, section 24 is engaged in the central hole 34 of the valve holder 3. As can be seen in Figures 1 to 3, the organ valve 2 is movable between a low closing position (fig. 2) and a position high suction (fig. 3). At rest, the valve member is in the state shown in the figure 1.

The outer surface of the frustoconical corolla 21 defines a contact surface 210 adapted to come into tight contact with the valve seat 13. A characteristic particularly advantageous of the invention lies in the fact that the solid angle that defines the outer wall of the frustoconical corolla 21 is greater than that which defines the frustoconical valve seat 16. Thus, in the rest position (fig. 1), the area of contact of the outer surface of the corolla 21 with the valve seat 16 is defined by a circle which is located in the upper end part of the valve seat. It exists thus a tip-shaped gap from the circular contact area down the valve seat. This difference is very small, because the difference in angle between the corolla and the seat is between 1 and 4 degrees. As a result, liquid can accumulate by capillarity in this tapered, point-like space. The accumulated liquid is used for sealing of the distribution chamber in the rest position. Improved sealing is thus achieved through the use of a valve member according to the invention. With a ball classic of the prior art, the accumulation of liquid by capillary action occurs only on a very short length. With the present invention, this length extends from the annular contact zone to the bottom of the corolla. The surface tension generated by this accumulation of liquid improves contact with the valve member on its seat.

According to the invention, the valve member is made of a non-rigid material such than polyethylene, polypropylene or thermoplastic elastomer. The organ valve is therefore endowed with a certain resilience. Because of this resilience, the corolla 21 may be subjected to compressive deformation stresses and / or elongation. In the rest position (fig. 1), the valve member is not subjected to any constraint. However, as soon as the pressure increases in the distribution chamber of the device, because the latter communicates with the valve chamber via the passage 34, the valve member 2 is subjected to the pressure prevailing in the body of pump. This pressure has the effect of strongly applying the corolla 21 to the seat of valve 16. Due to its resilience, the valve member undergoes a slight deformation which has the effect of increasing the contact area of the corolla with the valve seat. As shown in Figure 2, this contact area is no longer defined by a circle but by a frustoconical surface. The contact surface is thus greatly increased. This is made possible, because the corolla forms with the stem a kind of mushroom or overturned umbrella. The pressure in the distribution chamber exerts a force on the inner wall of the corolla which pushes the corolla towards the stem and generates its deformation. Because the angle between the corolla and the valve seat is very small, the necessary deformation is very small. Due to the shape and the elasticity of the corolla, the initial annular contact zone has become a zone tapered contact. In addition, the constraint exerted by the corolla in the area of initial circular contact is greatly increased. Resilience and pressure further increase the quality of contact with the valve seat. As long as the device distribution chamber remains under pressure, the valve member remains in the closed position shown in Figure 2. As soon as the pressure drops in the distribution chamber, contact breaks between the corolla and the valve seat. The next step is to fill the distribution chamber by suction of product through the intake channel 1. This has the effect of causing the flap up in its suction position.

According to the invention, means are provided for holding the valve member in the axis in this position. To do this, the corolla 21 of the valve member is extends at its free end by a circular part 22. This circular part 22 fulfills a double function. First, it can be used with its upper surface as a sliding pad at the outlet of the distribution bowl to obtain an orientation of the valve member. Then, the cylindrical part defines with its peripheral edge exterior in combination with the transition surface 25 a fictitious truncated cone which has a solid angle identical to that of the lamellae 35 in the transient part frustoconical 32 of the valve holder 3. Thus, in the suction position, the valve member has a double annular contact with the lamellae 35. This double annular contact keeps the valve member in the axis in abutment in its position suction. Although the valve member is free to move in its chamber valve, it is forced to position itself perfectly in the axis as well in position closing on its valve seat 16 only in suction position by double contact with the slats 35.

Because the valve member according to the invention is made of a material plastic and not steel, its inertia is lower and therefore its response to fluid passage is faster. It should also be noted that the particular shape of the corolla mushroom or inverted umbrella promotes its entrainment by the fluid closed position. Indeed, the pressurized fluid can rush into the concave volume defined between the corolla and the stem portion 23. At the start of placing under distribution chamber pressure, a small amount of fluid flows back towards the tank. This small amount of fluid drives the valve member on its seat. Thanks to the invention, this small amount of fluid is further reduced due to the speed with which the valve member moves to its closed position. Not only is the seal improved due to the frustoconical contact area, but still the sealing is obtained more quickly. In addition, the raw material used to make the valve member, in this case plastic, is much less expensive than the steel used to make balls.

Using a conventional pump body and a conventional valve holder, only by changing the valve member, better characteristics are obtained sealing.

Claims (10)

1. An inlet valve assembly integrated in apparatus for dispensing a fluid contained in a tank, the valve assembly serving to isolate a pump chamber from said tank at least during a dispensing stage during which said fluid is dispensed, and corresponding to a pressure increase in said pump chamber, said valve assembly comprising a valve member (2) having a contact zone coming into sealed contact with a substantially frustoconical valve seat (16) at least during said dispensing stage, the contact zone of the valve member (2) being part of a substantially frustoconical surface (210), said inlet valve assembly being characterized in that the solid angle of the frustoconical surface (210) is greater than that defined by the valve seat (16) so that the contact zone is at least initially defined by a circle when the valve member is at rest, and in that the frustoconical surface (210) is formed by a substantially flexible wall, so that the initially circular contact zone extends to form a truncated cone by resilient deformation during the dispensing stage.
2. An inlet valve assembly according to claim 1, in which the valve member (2) includes a cap (21) extending outwards frustoconically, and having an outside frustoconical wall that defines said frustoconical surface (210).
3. An inlet valve assembly according to claim 2, in which the valve member (2) includes a stem (23, 24) having a bottom end, the cap (21) being formed at said bottom end.
4. An inlet valve assembly according to any one of claims 1, 2, or 3, in which the displacement of the valve member is limited by a valve holder (3) between a closed position and a suction position.
5. An inlet valve assembly according to claims 3 and 4, in which the top end of the stem (23) is engaged in a passage (34) formed by the valve holder (3).
6. An inlet valve assembly according to claim 2, in which the cap includes a cylindrical end portion (22) extending the frustoconical wall (210).
7. An inlet valve assembly according to claim 2, in which the stem comprises two cylindrical sections (23, 24) of different diameters and interconnected by a transition surface (25).
8. An inlet valve assembly according to claims 4, 6, and 7, in which the valve holder (3) defines abutment means (35) for the valve member (3) in the suction position by coming into contact simultaneously with an outer end edge of the cylindrical end portion (22) and with the transition surface (25), so as to hold the valve member on the axis when it is in the suction position.
9. An inlet valve member according to any preceding claim, in which the valve holder used is a conventional valve holder normally suitable for receiving a ball.
10. An inlet valve assembly according to any preceding claim, in which the valve member is made of a plastics material.

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