Thrust regulator comprising a mounting enclosure

A regulator is housed in the expulsion channel of an aerosol container inside which there is a product that is to be dispensed, this product being subject to an expulsion pressure originating from a compressed gas, the said regulator comprising a flexible disk (6) and a rigid disk (7), the latter presenting a protrusion (8) with grooves (9), and further comprising a sealing disk (12) with a central bore (13), and further comprising a nozzle (16). With the flexible disk (6), the grooves (9) in the rigid disk (7) form ducts for the expulsion of the product, and are oriented so as to form tangents to the circumference of the axial duct (10) of the rigid disk (7). This arrangement of the component parts creates turbulence effects in the flow of expelled product, and these effects are utilized to regulate the flow rate at which the product is expelled.

The present invention relates to a thrust regulator which comprises a 
mounting enclosure, this thrust regulator being intended to maintain the 
flow rates of liquid or cream-like products at values that remain at least 
approximately constant during the expulsion of these products from aerosol 
containers by means of compressed gas, in accordance with the 
precharacterizing clause of claim 1. 
It is known that compressed gases, such as, for example, air or nitrogen, 
exhibit a pressure drop as soon as there is an increase in the volume of 
the container in which they are stored, such as occurs in the case of an 
aerosol container from which a product is being expelled. The flow rate of 
this product decreases in proportion to this fall in pressure. At the same 
time, when the product is atomized by means of a nozzle, there is an 
increase in the size of the droplets which are expelled, due to 
insufficient expulsion pressure. 
U.S. Pat. No. 4,487,334 and International Patent Application No. 
PCT/CH83/00122, published under the number WO 84/01930, describe thrust 
regulators which modify the flow cross-section of a duct, with the aid of 
a piston which co-operates with a spring, doing so under the influence of 
the pressure which expels the product from the aerosol container, in such 
a way that when the pressure is high, the flow cross-section is small, and 
increases in proportion to the fall in expulsion pressure. 
These regulators, manufactured in molded plastic, nevertheless demand very 
high precision if they are to function well, in the region of .+-.0.01 mm 
in the case of a piston diameter of less than 1 mm, such precision being 
very expensive. In fact, certain solvents, in particular methylene 
chloride, give rise to swelling of the plastic which is used, and this 
causes the piston to jam inside the expulsion duct and, in consequence, 
causes the system to become blocked. 
The object of the present invention is to eliminate these problems, and to 
propose a thrust regulator of the type defined in claim 1, annexed hereto.

FIGS. 1 and 2 show a regulator which is housed in a press-to-actuate head 
1, associated with an aerosol valve which is not represented. A vertical 
duct 2, communicating with the valve, opens into a chamber, 4, which 
exhibits a widened region 5. The chamber 4 is closed-off by a flexible 
disk 6, which is preferably made of stainless steel, but which can also be 
composed of a plastic. The flexible disk 6 is housed in the widened region 
5, where it is kept in place by means of a rigid disk 7. This disk 7 
presents a convex protrusion, 8, which is provided with a plurality of 
grooves 9, arranged in a manner such that they form tangents to the 
circumference of an axial duct 10. The grooves 9 present steps, 11, which 
are intended to create turbulence effects in the product which is passing 
through the regulator, under pressure. The disk 7 bears against a sealing 
disk 12, which is also preferably made of stainless steel, and which is 
provided with a bore 13. A nozzle 16, presenting a protruding portion 15 
and grooves 14, bears against the sealing disk 12, in a manner such that 
the grooves 14 act as ducts. 
The PCT Application which has already been cited describes the appearance 
of turbulence effects when the flow of a pressurized liquid is deflected 
through a right angle in the presence of a rod, in this case a piston, 
located in the duct upstream, these turbulence effects constituting a 
flow-retarding force, and being capable of developing so far as to stop 
the outflow. This retarding force is directly proportional to the pressure 
under which the liquid is being expelled: the higher the pressure, the 
greater the retarding force. 
The same Patent Application describes the automatic control of this 
retarding force, so as to regulate the thrust with which a product is 
expelled from an aerosol container. However, in this known application, 
the turbulence effects, and the retarding force which they create, depend 
also on the presence of a piston that is housed in a chamber 17 of the 
nozzle 16. If this piston is absent, the retarding force due to the 
turbulence effects is weaker. 
In order to eliminate the necessity for a high-precision plastic molding 
for the purpose of obtaining the required quality of regulation, the 
present invention does not involve a piston. So as to compensate for the 
lack of turbulence-created retarding force, due to the lack of a piston, 
the convex protrusion 8 is provided with grooves 9, which become ducts by 
virtue of the fact that the flexible disk 6 bears hard against them. 
Because these ducts form tangents to the periphery of the axial duct 10 in 
the rigid disk 7, turbulence effects appear, creating a retarding force, 
adding to the retarding force which is created by the nozzle 16, but which 
is weakened by the lack of a piston, in such a way that the regulator, as 
described, is endowed with a two-stage "turbulator". Since the disk 6 is 
flexible, it allows itself to be deformed by the pressure under which the 
product is expelled, in such a way that, given the convexity of the 
protrusion 8, the ducts present minimum flow cross sections under a high 
expulsion pressure, these sections enlarging in proportion to any fall in 
the expulsion pressure, following an extremely small displacement of the 
flexible disk 6 in the upstream direction. For this reason, flow 
regulation is brought about just as effectively by the enlargement of the 
flow cross-sections of the ducts 9, following a fall in expulsion 
pressure, allowing the flexible disk 6 to relax, as by variations in the 
retarding force due to turbulence effects, following variations in the 
expulsion pressure. 
The appearance of turbulence effects depends on the viscosity of the 
product which is to be expelled in order to be atomized by means of the 
nozzle 16. It has been noticed that, once the viscosity exceeds 8 
centipoises, the retarding force due to the turbulence effects starts to 
decrease, if the regulator operates as described, just as does the quality 
of regulation. In order to make good this quality shortfall, the flexible 
disk 6 can be replaced by a regulating disk 18, as illustrated in FIG. 3. 
In a first variant, this regulating disk 18 exhibits notches, 19 and 20, 
from which the leaf springs 21 and 22 result. When the pressure under 
which the product is expelled is high, the leaf springs 21 and 22 are 
depressed, and close-off at least two of the ducts 9. The more the 
expulsion pressure falls, the more the leaf springs 21 and 22 relax, in a 
manner such that the closed-off ducts 9 are opened in like proportion. 
When the regulator operates in this way, the quality of regulation is 
provided partly by the turbulence effects, but predominantly by the 
variations in the flow cross-sections of the ducts 9. 
FIG. 4 presents another embodiment of a regulator, which is intended for 
dispensing viscous products, such as creams, oils, mustards, etc. Given 
that products of this kind, exhibiting high viscosities, do not generate 
turbulence effects, their flow rates have to be regulated solely by 
varying the flow cross-sections under the influence of the fall in the 
expulsion pressure provided by the compressed gases which are utilized. 
Within a cylindrical seating 23 in a press-to-actuate head 24, are housed, 
upstream, a flexible disk 25, a first flexible regulating disk 26, 
presenting a leaf spring, 27, which can temporarily close a cut-out 28, a 
rigid disk 29, exhibiting a chamber 30 and an axial duct 31, the 
protrusion 8 not being visible, a flexible disk 32, a second flexible 
regulating disk 33, presenting a leaf spring, 34, which can temporarily 
close a cut-out 35, and a flexible disk 36, exhibiting a bore 37, the 
whole assembly being held in place by means of a dispensing device 38. 
The design details of the two flexible regulating disks, 26 and 33, are 
illustrated in FIGS. 5 and 6, which show them in cross-section and plan 
view respectively. The leaf springs 27 and 34, being sensed to bring about 
the temporary closing-off of the cut-outs 28 and 35, must be adjusted 
perfectly, and in order to prevent them from jamming in the cut-outs 28 
and 35 they are provided, at their bases, with raised portions, 39, which 
give them enough spring force to prevent them from jamming in the said 
cut-outs. In order to ensure that a minimum passage persists after closure 
of the cut-outs 28 and 35, each of the leaf springs 27 and 34 presents a 
small beak 40 at its free end, these beaks 40 shortening the active spring 
length by an amount which is a function of the angle 41. 
The embodiment of the regulator as shown in FIG. 4 operates in a manner 
which is illustrated by FIGS. 7 and 8, where the regulator is housed 
inside a cylinder 43, inside which a chamber 44 and an axial duct 46 are 
provided, the chamber 44 exhibiting a widened region 45. When the 
regulator is at rest, namely if no product is flowing out via the 
aerosol-container valve, which is not represented, the duct 46 is 
closed-off by the flexible disk 25, which is kept in the illustrated 
position by means of the leaf spring 27 belonging to the first flexible 
regulating disk 26, which, for its part, is kept in place by the rigid 
disk 29, this latter disk being provided with the protrusion 8 and the 
axial duct 31. 
The rigid disk 29 exhibits the chamber 30, in which the flexible disk 32 is 
housed, held in place by the leaf spring 34 of the second flexible 
regulating disk 33, which bears against the flexible disk 36. The complete 
assembly is held in place by the dispensing device 38. When the valve, 
which is not represented, is opened, the product 47, expelled by the 
pressure acting inside the aerosol container, presses the flexible disk 25 
in the downstream direction, thus opening the axial duct 46 while 
displacing the leaf spring 27 in the downstream direction, partially 
closing the cut-out 28 and leaving open only a flow cross-section which 
corresponds to the expulsion pressure. At the moment of maximum expulsion 
pressure, this passage will be minimal, by virtue of the small beak 40. 
Thus, at any moment while the valve is open, the product 47 can flow out 
via the axial duct 31, and can act on the flexible disk 32, which in its 
turn displaces the leaf spring 34 of the second flexible regulating disk 
32 in the downstream direction, placing it over the mouth of the bore 37, 
this movement reducing the cross-section available for flow through this 
bore, to an extent which depends on the expulsion pressure but, by virtue 
of the small beak 40, leaving a minimum passage at any time while the 
valve is open, via which passage the product 47 can flow out via the 
dispensing device 38, through a duct 48. As the pressure expelling the 
product 47 falls, the leaf springs 27 and 34 press the flexible disks 25 
and 32 proportionately more and more in the upstream direction, thus 
opening the cut-outs 28 and 35 more and more, in such a way that the 
product flow rate remains at least approximately constant. 
FIG. 9 shows advantageous variants of the flexible regulating disks 26 and 
33, presenting different numbers of variously-shaped leaf springs 27 and 
34, for taking account of a desired flow rate, and for taking account of 
the viscosity of the product 47 which is to be dispensed. The force 
exerted by the leaf springs 27 and 34 can be varied by varying the width 
over which they are attached to the flexible regulating disks 26 and 33. 
FIG. 10 shows another embodiment of a regulator, such as is advantageously 
utilized in the press-to-actuate head according to the invention. This 
regulator is intended to refine the regulation, especially for utilizing 
the regulator as a means of atomizing a hairspray in a manner enabling it 
to be applied to the hair with a cone of atomization exhibiting an angle 
which is as constant as possible. Given that the appearance of 
retardation-creating turbulence effects depends on the product viscosity, 
and that the viscosity of the hairspray may be variable, depending on the 
quality of "hold" required, the regulation due to turbulence effects has 
to be supplemented by another means of regulation, which in this case 
functions by varying the flow cross section in accordance with the 
variations in the expulsion pressure under which the product flows out 
through the regulator. 
The regulator shown in FIG. 10 closely resembles the one shown in FIGS. 1 
and 2, with the difference that the rigid disk 7 exhibits twelve grooves 9 
in the protrusion 8, instead of six, and that a regulating disk 18 is 
housed between the rigid disk 7 and the sealing disk 12, inside a chamber 
30 which is not visible, but which is provided in the downstream face of 
the rigid disk 7, just as illustrated in FIG. 4. When this regulator comes 
into operation, because the valve of the aerosol container has been 
opened, the flexible disk 6 is displaced towards the upstream face of the 
rigid disk 7, so that the grooves 9 become ducts, giving rise to 
turbulence effects at the mouth of the axial duct 10. The product then 
displaces the regulating disk 18 onto the upstream surface of the sealing 
disk 12, thus covering the bore 13. The force exerted by the leaf springs 
21 and 22 is chosen to be such that a minimum flow cross-section persists 
between the downstream face of the regulating disk 18 and the upstream 
face of the sealing disk 12,; so as to guarantee a minimum flow rate when 
the product is being expelled under a high pressure. As the expulsion 
pressure falls, the leaf springs 21 and 22 relax proportionately, and lift 
the regulating disk 18, this lifting movement gradually increasing the 
flow cross-section in like proportion to the fall in the expulsion 
pressure. 
FIG. 11 shows a further embodiment of a regulator, housed in a cylindrical 
enclosure 51, exhibiting a supply duct 52, which opens into the chambers 
53 and 54. A regulating disk 55 is located inside the chamber 54, this 
disk 55 preferably being made of stainless steel and exhibiting a notch 
56, located on its centerline and in the direction in which the metal was 
rolled. This regulating disk 55 is given a curvature, 57, which is 
preferably perpendicular to the notch 56 and hence perpendicular to the 
direction in which the metal was rolled. The spring force resulting from 
the curvature 57 is very strong, giving little possibility of adjustment 
if the curvature is made in the direction of rolling. On the other hand, a 
curvature, 57, made perpendicularly to the direction of rolling offers a 
weaker spring force, with a wider range of adjustment. The spring force 
can also be adjusted with the aid of the notch 56: the greater its length, 
the more it reduces the spring force. On the other hand, the length of the 
notch 56 influences the product flow rate by extending more or less close 
to a through-hole 59 in an accelerating disk 58. The notch 56 is essential 
by reason of the fact that a very high initial pressure inside the aerosol 
container, for example 10 bars, could press the regulating disk 55 so hard 
against the accelerating disk 58 that the through hole could be 
closed-off. This closing-off is prevented by the notch 56. A disk 62 is 
located between the accelerating disk 58, with its through-hole 59, and a 
rigid disk 60, possessing a through-hole 61, the disk 62 exhibiting a 
chamber 63. The size of the through-hole 59 brings about an acceleration 
of the product flow, while reducing the pressure under which it is 
expelled, but which recovers in the chamber 63, so that the flow can be 
accelerated anew by the reduced size of the through-hole 61, the pressure 
recovering, once again, in a chamber 64, belonging to an atomizing nozzle 
65. The conversion, into expulsion pressure, of the product flow velocity, 
occurring in the chambers 63 and 64, is favorable to the quality of 
regulation achieved by the regulator. It must be noted that the provision 
of a large through-hole 61 requires that, a higher spring force be exerted 
by the regulating disk 55, as opposed to when this hole 61 is small. 
Several parameters are therefore available for obtaining the required 
regulation. The thickness of the regulating disk 55 is also one of these 
parameters. These different parameters enable the regulator to be adjusted 
to suit the viscosities of the various products which are to be dispensed, 
ranging from water, through alcohol and oil, to products of a creamy 
consistency. 
The disk 62 is preferably manufactured as a plastic molding, while the 
accelerating disk 58 and the rigid disk 60 are preferably made of 
stainless steel. Due to this fact, the sizes of the through-holes 59 and 
61 cannot be affected by a solvent employed in an aggressive formulation, 
for example methylene chloride. Moreover, the accelerating disk 58 and the 
rigid disk 60 cover the surface blemishes on the upstream and downstream 
faces of the disk 60, these blemishes deriving from the molding process, 
an example being the marks left by an extractor. 
The regulating disk 55, the accelerating disk 58, the rigid disk 60, and 
the disk 62 are held in place by the atomizing nozzle 65, which is 
preferably like the one described in European Patent No. 688, and which is 
firmly fixed inside the cylindrical enclosure 51, the dimensions of the 
said disks being chosen so as to ensure perfect sealing between their 
peripheries and the said enclosure 51. This atomizing nozzle 65 can be 
replaced by a simple tube, typically for dispensing oily or creamy 
products. 
The regulator shown in FIG. 11 operates in a manner which is illustrated, 
in part, by FIGS. 12 to 15, namely as follows: at rest, when the valve of 
the aerosol container is closed, the disk 55 is caused to bear, by its own 
spring force, against the through-hole 59 in the accelerating disk 58, 
allowing the passages x (FIG. 14) to remain effective. As soon as the 
pressure acting on the product to be dispensed acts on the regulating disk 
55, the curvature 57 flattens out, this flattening reducing the flow 
cross-section of the through-hole 59, so that x becomes x-y (FIG. 15). As 
the expulsion pressure acting on the product to be dispensed falls, the 
spring force exerted by the regulating disk 55 re-establishes the shape of 
the curvature 57 in like proportion, namely in proportion to the fall in 
the expulsion pressure prevailing in the product, and progressively opens 
the flow cross-section of the through-hole 59, so as to arrive, 
ultimately, at the cross-section which provides the flow cross-section x, 
in particular when the aerosol container is becoming empty. The pressure 
prevailing in the chamber 53 acts as a check on the inflow of product via 
the through-hole 59, namely as a retarding force which weakens 
progressively as the expulsion pressure falls, and which therefore forms 
one of the means of regulation possessed by the regulator that has been 
described.