Untitled record

PATENT

FRENCH REPUBLIC

MINISTRY OF INDUSTRY

INDUSTRIAL PROPERTY SERVICE

PV n ° 36.701 International classification:

-ï ^ .461.685 _F16k

<img file="FR1461685A_D0001.tif" />

Improvement to metering valves operating under the action of a compressed gas.

Civil society known as: IDEAS residing in France (Seine).

Requested on October 29, 1965, at 3 p.m.¹¹ 7^m, in Paris.

Issued by order of November 2, 1966.

(Official bulletin of industrial property, n ° 50 of December 9, 1966.) (Patent of invention whose delivery was deferred in execution of article 11, § 7, of the law of July 5, 1844 modified by the law April 7, 1902.)

There are several types of metering valves operating under the action of a compressed gas. These valves use a deformable wall through which the pressure supplied by the propellant gas is transmitted to the product to be ejected.

The wall must be elastic, on the one hand, to be able to return to its initial shape after compression and expulsion of the product, on the other hand, to allow the bag to aspirate a new dose.

The current means used to obtain this result are as follows:

1 ° Use of rubber to make the dosing chamber, this material having sufficient own elasticity to allow the aspiration of the dose.

Unfortunately, many products have a swelling or dissolving action on natural or synthetic rubbers and this greatly limits the possibilities of the valve.

2 ° Realization of a metering chamber in non-elastic plastic material, polyethylene for example and having an accordion shape giving it the desired elasticity.

This dosing chamber is difficult to make and if the product is a little viscous, it does not have sufficient elasticity to return to the first position by aspirating the dose. In addition, gas bubbles often remain attached, immobile in the folds of the accordion and distort the dose by projecting outward a supplement of product whose volume is represented by the difference between the volumes occupied by the bubble under pressure. and relaxed.

In these two cases, the pressure required to flatten the chamber and evacuate the dose increases as the flattening progresses, and it may happen that the available pressure becomes insufficient to ensure correct distribution of the product at the end of the dose. .

To overcome these drawbacks and in accordance with the invention, a rigid metering chamber is provided, consisting of a cylinder inside which a free piston moves, subjected to the action of a return spring.

To avoid the increase in resistance as the dose is emptied, the volume of the chamber is much greater than that of the dose evacuated and the piston is stopped, in its course, before the resistance does has increased significantly; this makes it possible to obtain doses which vaporize correctly until the end.

According to one embodiment, the metering valve comprises an enclosure, formed by two superimposed and communicating chambers, in which are arranged two mobile and independent members, a valve and a piston, both being subjected to the action of return springs, the controlled displacements of the valve ensure, either the communication of the enclosure with the product, or after interruption of this communication, the connection of the enclosure with the outside, the piston subjected to the action of the pressure of the product then being moved within the enclosure and thus causing the expulsion, under pressure, of a certain quantity of product, which constitutes the desired dose, the piston returning to its position rest when, by actuation of the valve, communication is re-established between the enclosure and the product.

The shape of the valve assembly being compact, there are few possibilities for bubbles to cling to the walls and this increases the accuracy of the dose.

The description which follows with reference to the appended drawing given by way of nonlimiting example will make it clear how the invention can be implemented, the particular features which emerge both from the drawing and from the text forming, of course, part of said invention.

2191 0 73 833 3 ♦

Booklet price: 2 francs - 2 - [1,461,685]

Figure 1 shows, in axial section, a metering valve produced according to the invention, this valve being shown in the rest position.

FIG. 2 shows the valve in the position for dispensing a dose.

The metering valve comprises a body 1 inside which are housed all the parts constituting the valve, these parts being retained in the body 1 by a capsule 2 set on the cord 1a of the body.

The body 1 is connected, in the usual way, to a dip tube 3.

A sheath 4, extending over almost the entire height of the body 1, is engaged with gentle friction, at the location of the bearing 4a, in the bore of said body 1; the outer diameter of the sleeve is smaller than that of the bore of the body so as to leave an annular space 5 between the sleeve and the bore of the body. This annular space 5 is in communication, on the one hand, with the interior of the sheath 4 by lateral holes 6, on the other hand, by notches 6a - established along the lower hord 46 of the sheath 4 - with the inside the dip tube 3, that is to say with the inside of the container carrying the metering valve.

The interior of the sheath 4 constitutes an enclosure comprising two superimposed cylindrical chambers 7 and 8 communicating with each other through the central hole

9.

In the chamber 7 is housed a valve 10 normally applied to a seal 11 by the action of a spring 12. This valve is provided with two annular seals 13 and 14. An axial drilling 15 of the valve 10 is put in communication with the outside via a conduit 16.

The valve 10 is extended by a rod 10a comprising an axial bore 17 into which opens a conduit 18, the external orifice of which is disposed below a seal 19 clamped by the capsule 2 on a wedge 16 resting on the attached 11.

In the chamber 8 can slide a piston 20 with circular seal 21. This piston is subjected to the action of a spring 22 acting to maintain the piston in the end-of-travel position towards the bottom 16 of the body 1.

The operation of the metering valve thus produced takes place as follows.

In the rest position (fig. 1) the compressed gas trapped in the container on which the valve is mounted, discharges the product contained in said container - through the plunger 3, the annular space 5 and the conduits 6 - into the inside of the sheath 4 and fills the free volume.

When one acts, in direction F (fig. 2) on the spraying head, represented diagrammatically at 23, one causes the sliding, of downward, of the valve 10. In a first part of the stroke, the seal 14 is brought below the channels 6, which cuts the communication between the interior of the container and the interior of the sheath 4.

In the second part of the valve stroke, the conduit 18 is brought beyond the seal 11 (fig. 2) which places the interior of the sleeve 4 in communication with the borehole 17 and the spray orifice, c that is to say with the atmosphere.

Under the effect of the pressure of the product contained in the container, the piston 20 is driven upwards by compressing the spring 22. During its movement - limited by a stop 24 - the piston expels - a certain amount of product by drilling 15, the conduits 16 and 18 and the drilling 17, following the path indicated by the arrows f to. the. figure 2.

When the product is no longer expelled under pressure, it ceases to act on the head 23. Under the action of the spring 12, the valve 10 is brought into abutment on the seal 11, the conduit 18 then being disposed between the two seals 19 and 11, while the seal 14 is returned above the conduits 6 thus putting the interior of the sheath 4 in communication with the interior of the container.

Under the effect of the spring 22, the piston 20 returns to its original position, the suction effect, resulting from the stroke of the piston, completes the action of pressure on the product to completely fill the interior of the scabbard 4.

A new quantity of the same volume as the quantity expelled previously can then be dispensed by depressing the valve 10.

This quantity constitutes the dose of the product expelled at each operation of the valve 10. This dose is defined by the difference between the free volume inside the sleeve 4 when the valve 10 and the piston 20 are in the rest position (FIG. 1) and the free volume when the valve and the piston are in the positions indicated in FIG. 2.

It is possible, in a valve provided for a determined dose, to modify the value of said dose by acting on the length of the stroke of the piston 20.

In fact, the greater the stroke of the piston 20, the greater the difference between the two abovementioned volumes and vice versa, the shorter the stroke of the piston 20, the smaller the difference between the volumes.

By using standard parts, it is then enough, to increase the stroke of the piston 20, to reduce the height h of the latter and, to reduce this stroke, to insert a washer 25 between the upper edge of the piston and the stop 24 , or - although this solution is less recommendable, because it modifies the elastic characteristics of the spring 22 - to insert a washer 25a between the bottom 20a of the piston and the bottom 16 of the body 1, this washer comprising, on its hord in contact with the bottom 16, notches similar to the notches 6a of the sheath 4.

It goes without saying that modifications can be made to the embodiments which have just been described, in particular by substitution of equivalent technical means, without going beyond the ambit of the present invention.