FR2835203A1 - SPRAY NOZZLE WITH REDUCED DIAMETER - Google Patents

Abstract

In a liquid spray nozzle according to the invention, the swirl chamber (7) communicates with the exterior through a converging conical coaxial outlet hole (10) and communicates with the inlet through a plurality of transfer channels (11 -15) oblique. Each first transfer channel (11) is limited by an outer face (21) with a generally rectilinear profile connecting tangentially to the peripheral wall (8) of the swirl chamber (7), while the inner face (22) has a concave profile over most of its length. This improves the distribution and fineness of the droplets sprayed at the outlet of the nozzle, in particular when the liquid has a greater viscosity than that of water.

Description

SPRAY NOZZLE WITH REDUCED DIAMETER

  The present invention relates to liquid spray nozzles, in which a liquid to be sprayed is brought into a central swirl chamber by peripheral transfer channels tangentially injecting the swirling liquid into the central swirl chamber and then leaves the central chamber. Turning by a passage

  coaxial output to the atmosphere.

  Such spray nozzles are capable of being used in sprayers, in combination with spray pumps with manual actuation or with a push gas,

  especially for spraying cosmetic products.

  There are already known such spray nozzles, described in particular in the document EP 0 000 688 A, comprising a twisting chamberDissillon having a general shape of revolution around a longitudinal axis, limited by a peripheral wall, by a rear wall, and by a front wall pierced with a coaxial outlet hole. A coaxial circular channel surrounds the swirl chamber, and communicates with said swirl chamber through a plurality of first oblique peripheral transfer channels which inject the rotating liquid in a direction of rotation into the swirl chamber. A plurality of second transfer channels conduct the liquid from a liquid inlet and feed it into the coaxial circular channel in rotation in said direction of rotation. The first transfer channels are each limited by an outer face with a straight profile which tangentially connects to the peripheral wall of the swirl chamber, and which angularly connects to the inner wall of the coaxial circular channel. Said first transfer channels are each limited by an inner face with a straight profile which is angularly connected to the peripheral wall of the swirl chamber, and which is angularly connected to the internal wall of the coaxial circular channel. The cross section of the first transfer channels is gradually reduced from the coaxial circular channel to the chamber

of whirling.

  Such two-stage spray nozzles work relatively well for spraying low viscosity liquids such as water, producing droplets of satisfactory sizes, of the order of 90 microns, distributed in a spray cone at the outlet of nozzle. However, such spray nozzles produce a very insufficient spray, that is to say much too large droplet sizes, when the liquid to be sprayed has a viscosity greater than that of water. This defect prevents the satisfactory use of such spray nozzles for spraying cosmetic products having medium viscosities, for example viscosities higher than

0.8 Pa.s.

  The presence of the coaxial circular channel and of the second transfer channels increases the diameter of the nozzle, and reduces its possibilities of incorporation in the miniaturized spray heads of the cosmetic spray devices. But on the other hand, their presence seems necessary to achieve a

  correct spraying of liquids with low viscosity.

  Another difficulty results from the relatively low fluid pressure produced by the manual pumps of the cosmetic spraying devices, which further reduces the spraying capacities and tends to increase the size of the sprayers.

droplets produced.

  There is also an uneven distribution of the droplets of liquid sprayed into the spray cone, with a greater concentration of droplets in the area

center of the cone.

  In addition, in mass production, it is found that the spraying qualities vary considerably depending on the nozzles considered. This results from too great sensitivity to variations in nozzle dimensions within the tolerances

Manufacturing.

  The problem proposed by the present invention is both to reduce the size of the spray droplets at the outlet of a nozzle supplied with liquid, to ensure a homogeneous distribution of the droplets in the spray cone in the case of relatively low fluid pressures. and variables produced by hand pumps of cosmetic spray devices, and to achieve these effects with a spray nozzle

reduced diameter.

  The invention results from the observation according to which a reduction in the sizes of spraying droplets at the outlet of the nozzle can be obtained by promoting the acceleration of the fluid towards the peripheral wall of the swirl chamber, and by avoiding as much as possible the zones dead at low speed the

  liquid in the channels or chambers of the spray nozzle.

  At the same time, excessive dispersion of the spray cone is avoided by giving the axial outlet hole a conical shape.

  appropriate, converging towards the exit.

  To achieve these and other objects, a spray nozzle according to the invention, for spraying liquids, comprises: - a swirl chamber having a general shape of revolution around a longitudinal axis, limited by a peripheral wall , by a rear wall, and by a front wall pierced with a coaxial outlet hole, - a plurality of oblique transfer channels injecting the liquid in rotation in a direction of rotation into the revolving chamber, the transfer channels are limited each by an outer face with a generally rectilinear profile and tangentially connecting to the peripheral wall of the swirl chamber, - the transfer channels are each limited by an inner face having a concave profile over most of its length, - the exit coaxial hole has a conical shape converging towards the exit. With such a spray nozzle structure, the total diameter of the nozzle is significantly smaller than that of two-stage nozzles. It can also be seen that the droplet sizes sprayed at the outlet of the nozzle are much smaller than those obtained by the nozzles of the prior art mentioned above. It is estimated that about 30% is saved on the size of the droplets sprayed at the outlet, with an equal pressure generation system. By way of example, for liquids with a medium viscosity of between 800 and 1000 mPa.s, it has been possible to obtain an average droplet diameter of between about 95 microns and about 65 microns. In addition, the average distribution of the droplets is homogeneous in the spray cone at the outlet.

nozzle.

  An advantageous effect of the invention is also a relative independence of the quality of spraying produced with respect to the pressures and flow rates supplied by the pusher device which

  introduces the liquid at the inlet of the nozzle.

  Another effect of this particular nozzle structure according to the invention is an acceptance of higher tolerances of concentricity of the outlet hole with respect to the swirl chamber when spraying relatively viscous liquids: the spraying is excellent when the outlet is centered, but it remains acceptable when the outlet hole is logically off-center. Good results can be obtained up to an offset offset of about 10% of the diameter of the outlet hole, for liquids whose viscosity is included

between 800 and 1000 mPa.s.

  Conversely, in known spray nozzles, a decentering of the outlet hole leads to a significant degradation of

spraying.

  Preferably, according to the invention, each transfer channel is supplied by a longitudinal supply channel

  device from the nozzle entrance.

  According to a preferred embodiment, the inner face with a concave profile of the transfer channel is generally circular according to a radius of between one and a half and two times the radial distance DR between the corresponding peripheral longitudinal supply channel and the turning chamber. . This reduces the presence of dead zones, that is to say zones in which the liquid takes a slow speed in the nozzle.

  spraying, and spraying is improved.

  For a better spraying of thixotropic liquids, it is preferable to avoid pressure drops and dead zones inside the nozzle. Thus, it can advantageously be provided for the external wall of the peripheral longitudinal supply channel to be connected to the front front wall of the

  corresponding transfer by a regular rounded area.

  According to an advantageous embodiment, the inner face with a concave profile of the transfer channel is connected to the corresponding peripheral longitudinal feed channel by a rounded convex zone. This feature also reduces the

  presence of dead zones, and improves spraying.

  For the same reasons, it is also possible to prefer an external face with a generally rectilinear profile of the transfer channel which is connected to the longitudinal supply channel.

  corresponding peripheral by a convex rounded zone.

  It may be advantageous, to improve the spraying, to provide that the internal face with a concave profile of the transfer channel is connected to the peripheral wall of the

  swirling by a convex rounded connection zone.

  For a regular distribution of the droplets at the outlet of the nozzle, the cone angle of the outlet coaxial hole is

  between 15 and 30, advantageously around 20.

  A better distribution distribution of droplets at the outlet of the nozzle is also obtained by using transfer channels five in number, distributed regularly around the longitudinal axis of the nozzle. This effect apparently results from the fact that the greater number of channels reduces the duration of the transient spraying establishment regime and makes it possible to reach the steady state more quickly. Compared to a three-channel nozzle, the initial transient regime is reduced, and in particular the spraying angle at the nozzle outlet more quickly reaches the steady-state angle. For example, measurements were made on a known nozzle with three channels and on a nozzle according to the invention at the instant 0.0001 second after the start of operation: with the nozzle of the prior art, the angle is of 9, ie 25% of the steady-state angle i with the nozzle according to the invention, the angle is 24, or 50 of the steady-state angle. The invention provides a liquid sprayer, which comprises a spray nozzle as defined above Such a sprayer has advantages for the spraying of all types of liquids, and it also has advantages in particular when it contains a sprayer liquid whose viscosity is between 800 and 1000 Pa approximately, and the density of which is between 1000 and 1100 kg / m approximately Excellent results are obtained when the ulverizer contains a thixotropic liquid Other objects, characteristics and advantages of the present invention will emerge from the description following modes of ral1sat10n particullers, made in relation to the attached figures, pa = mi which - Figure 1 is an overall view of cat in longitudinal section of a spray nozzle according to a particular embodiment of 1 invention, comprising a central channel engaged in a female nozzle body; - Figure 2 is a view of the rear face of the female nozzle body structure of Figure 1; - Figure 3 is a diamAtral longitudinal section of the female nozzle body structure along the plane C-C of Figure 2; - Figure 4 is a perspective view of three quarters rear of the female nozzle body structure; - Figure 5 is a partial arr1Are view of Figure 2, showing the curdure of the faces of the channels on a larger scale; and the figure is a general schematic view of a sprayer according to the invention. In the embodiment illustrated in the figures, a spray nozzle according to the invention comprises a nozzle body 1 comprising a cylindrical housing 2 open towards 1 ' rear and closed towards the front by a front wall 3 A channel 4 (figure 1) generally cylindrical With full front face 5 is engaged coaxially in the cylindrical housing 2 of the nozzle body 1,

  coming to bear on the rear face 6 of the front wall 3.

  The front face 5 can advantageously be bordered by a leave a. Housing and grooves are provided on the rear face 6 of the front wall 3, to form the chambers and channels of the spray nozzle according to the invention. There is thus a turning chamber 7, having a general shape of revolution around the longitudinal axis II, limited by a peripheral wall 8, by a rear wall formed by the core 4, and by a front wall 9 pierced with a coaxial outlet hole 10. The spray nozzle comprises five oblique transfer channels such as channels 11, 12, 13, 14 and 15. The transfer channels 11-15 tangentially inject the liquid into the swirl chamber 7 by printing on it a rotation around axis II, for example in the direction of rotation of the hands

of a watch in Figure 2.

  Five peripheral longitudinal supply channels such as channels 16, 17, 18, 19 and 20 conduct the liquid from a liquid inlet 40 and inject it into a

respective transfer 11-15.

  The transfer channels 11-15 are distributed equitably around the swirl chamber 7 and have the same shape, so that the spray nozzle has symmetry about the longitudinal axis I-I. We will therefore describe the shape of only one of the transfer channels. This shape is as shown to scale in Figures 2, 4 and 5, which can be

back for more details.

  Thus, in FIG. 5, the transfer channel 11 is limited by an external face 21 and by an internal face 22: the external face 21 is the face furthest from the longitudinal axis II, while the internal face 22 is the side closest to the longitudinal axis II. The outer face 21 has a generally rectilinear profile and is tangentially connected according to the connection zone 23 to the wall

  peripheral 8 of the swirl chamber 7.

  The inner face 22 of the transfer channel 11 has a

  concave profile L1 over most of its length.

  The inner face 22 with concave profile L1 can be generally circular according to a radius advantageously between one and a half and two times the radial distance DR between the corresponding peripheral longitudinal supply channel 16

  and the swirl chamber 7.

  The inner face 22 with concave profile L1 of the transfer channel 11 can be connected to the longitudinal supply channel

  peripheral 16 by a convex rounded zone 24.

  The outer face 21 with a generally straight profile of the transfer channel 11 can be connected to the supply channel

  longitudinal peripheral 16 by a convex rounded zone 25.

  Finally, the inner face 22 with concave profile L1 of the transfer channel 11 can be connected to the peripheral wall 8 of the turning chamber 7 by a rounded convex connection zone 26 with a small radius. The radius of curvature of the convex connection zone 26 can be between 50 microns and 80

approximately microns.

  The ccaxial outlet hole 10 can advantageously be centered on the longitudinal axis I-I according to a tolerance less than the diameter of the coaxial outlet hole 10, for example less than approximately 40 microns for an outlet diameter of 400

  microns, preferably less than 30 microns.

  Similarly, the outlet axial hole 10 can be aligned on the longitudinal axis I-I with a deviation tolerance of less than

4 approx.

  The coaxial outlet hole 10 according to the invention is

  conical, converging downstream or towards the outlet of the nozzle.

  The cone angle A of the outlet coaxial hole 10 is between

    and approximately 30, advantageously approximately 20.

  What is important is that the coaxial outlet hole 10 is conical over most of its length from the inlet port. In other words, the coaxial outlet hole 10 can be connected to the external face of the anterior wall 3 by a leave or a toric surface, without this adversely affecting the spraying performance. The cross section of the first transfer channels 11-15 can advantageously gradually reduce from the peripheral longitudinal orientation channel towards the swirl chamber 7. For example, the inside and outside faces can make an angle B of about 15. Their front side (in front wall 3) and rear wall (front side 5 of channel 4) can advantageously be parallel, to facilitate

the making.

  Considering FIG. 1, it can be seen that the external wall of the peripheral longitudinal feed channel 16 is connected to the front front wall of the corresponding transfer channel 11 by a regular rounded zone there. In this way, the flow of the fluid is improved by reducing its disturbances in the zone upstream from the transient channels and the

13 swirl.

  ['accAlAration of the fluid is done gradually from the inlet 40 of the nozzle to the outlet out of the outlet ccaxial hole 10. This promotes the spraying of all types of

  liquids, especially thixotropic liquids.

  The channel forms are entirely formed in the nozzle body, the channel 4 being simply cylindrical, possibly with a Sa cong. This thus facilitates the manufacture of the nozzle, making it possible to produce large nozzles from small

  diamAtre for cosmetic applications.

  Particularly advantageously, the shape of the nozzle according to the invention produces a dynamic spraying effect: depending on the pressure, the fractionation of the droplets remains satisfactory, but their distribution is modified in the spraying cane. [when the pressure is low, the droplets tend to concentrate in the center of the spray cane, while at higher pressures the droplets tend to react in the periphery of the cane. During a spraying sequence, under the action of a marional force, the pressure begins with low values, then gradually increases to then decrease until! low values. As a result, the droplets are first concentrated towards the center of the spray cane, then concentrated in the periphery and finally concentrated again in the center, so that the average distribution of the droplets is substantially constant in the cone of

  spraying at the end of the spraying sequence.

  The nozzle structure thus defined promotes the acceleration of the fluid inside the channels and in the swirl chamber, thus producing at the outlet of the nozzle a spray with particularly fine droplets, the size of which is at least 30% smaller. compared to the droplets

  obtained by known spray nozzles.

  The general dimensions of the spray nozzle according to the invention can be chosen according to the desired flow rate of liquid. One can in particular make small spray nozzles for cosmetic applications, for example having the following main dimensions: - diameter of the swirl chamber: about 1 mm; length of swirl chamber: approx. 0.40 mm;

  - outside diameter of the nozzle: about 4.5 mm.

  In the embodiment illustrated schematically in Figure 6, a liquid sprayer 27 comprises a container 28, a pump 29 and a spray nozzle 30 as defined above. By actuation of the button 31, the pump 29 is actuated which sucks the liquid 32 from the container 28 by a dip tube 33 and injects it under pressure into the spray nozzle 30 which

  produces, at the outlet, a spray cone 34.

  The particular structure of the spray nozzle 30 according to the invention allows the correct operation of such a sprayer 27 containing a liquid 32 to be sprayed, the viscosity of which may be greater than that of water, which may be between 800 and 1000 mPa .s approximately, and whose density is

  between 1,000 and 1,100 kg / m3 approximately.

  Good results can also be obtained when

  the liquid 32 has thixotropic properties.

  The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained in the field.

of the claims below.

Claims (10)

  1 - Spray nozzle for spraying liquids, comprising: a twisting chamber (7) having a general shape of revolution around a longitudinal axis (II), limited by a peripheral wall (8), by a rear wall ( 5), and by a front wall (9) pierced with a coaxial outlet hole (10), - a plurality of oblique transfer channels (11-15) injecting the liquid in rotation in a direction of rotation into the chamber swirl (7), characterized in that: - the transfer channels (11-15) are each limited by an outer face (21) of generally rectilinear profile and tangentially connecting to the peripheral wall (8) of the swirl chamber (7), - the transfer channels (11-15) are each limited by an inner face (22) having a concave profile (L1) over most of its length, - the coaxial outlet hole (10) a a converging conical shape towards the exit.   2 - Spray nozzle according to claim 1, characterized in that each transfer channel (11-15) is supplied by a peripheral longitudinal supply channel   (16-20) from the inlet (40) of the nozzle.   3 - Spray nozzle according to claim 2, characterized in that the inner face (22) with concave profile (L1) of transfer channel (11-15) is generally circular according to a radius between one and a half and two times the radial distance (DR) between the corresponding peripheral longitudinal supply channel (16-20) and the twirl (7).   4 - Spray nozzle according to one of claims 2   or 3, characterized in that the internal face (22) with concave profile (L1) of transfer channel (11-15) is connected to the corresponding peripheral longitudinal supply channel by a zone convex rounded (24).   - Spray nozzle according to any one of   Claims 2 to 4, characterized in that the outer face   (21) with a generally rectilinear transfer channel profile (11-15) is connected to the corresponding peripheral longitudinal feed channel (16-20) by a convex rounded zone (25). 6 - Spray nozzle according to any of the   claims 2 to 5, characterized in that the outer wall of the   peripheral longitudinal feed channel (16-20) connects to the anterior front wall of the corresponding transfer channel   (11-15) by a rounded rounded area (16a).   7 - Spray nozzle according to any one of   Claims 1 to 6, characterized in that the inner face   (22) with concave profile (L1) of transfer channel (11-15) is connected to the peripheral wall (8) of the swirl chamber   (7) by a convex rounded connection zone (26).   8 - Spray nozzle according to claim 7, characterized in that the radius of curvature of the convex connection zone (26) is between 50 microns and 80 approximately microns.   9 - Spray nozzle according to any one of   Claims 1 to 8, characterized in that the coaxial hole of   outlet (10) is centered on the longitudinal axis (I-I) with a tolerance less than 10 O of the diameter of the hole, advantageously less than 40 microns, preferably less than 30 microns.   - Spray nozzle according to claim 9, characterized in that the coaxial outlet hole (10) is aligned on the longitudinal axis (I-I) with a deviation tolerance less than about 4.   11 - Spray nozzle according to any one of   Claims 1 to 10, characterized in that the cone angle of the   coaxial outlet hole (10) is between 15 and 30, advantageously about 20.   12 - Spray nozzle according to any one of   Claims 1 to 11, characterized in that the channels of   transfer (11-15) are five in number, distributed evenly   around the longitudinal axis of the nozzle.   13 - Liquid sprayer (27), comprising a nozzle   spray (30) according to any one of claims 1 to   12. 14 - Sprayer (27) Solon the revindication 13, S characterized in that it contains a liquid (32) to be sprayed whose viscosity is between 800 and 1000 mPa.s approximately, and of which   the density is between 1000 and 1100 kg / m3 approximately.   - Sprayer (27) according to one of claims 13