Note: Descriptions are shown in the official language in which they were submitted.
20~2~2
DPV 58 22nd Cctober 1991
GK/B
DEUTSCHE PRAZISIONS-VENTIL GMBH
ACTUATING FITMENT FOR A SPRAY CONTAINER
The invention relates to an actuating fitment for a spray
container which contains a product which is capable of flow and which
is exposed to a gas pressure, and in a delivery duct a delivery valve
which is actuable by the actuating fitment so that the product flows
out through the delivery duct when the delivery valve is opened,
wherein the actuating fitment has an axial bore which can be coupled to
the delivery duct, a transverse bore leading from the axial bore to a
discharge nozzle, and a regulating member which is snugly fitted in the
axial bore and is axially displaceable, for through-flow regulation,
with a throttle bore.
In a known actuating fitment of that kind (EP 234 797 Bl), the
regulating member is in the form of a rubber disc which is pressed
axially against an opening of the axial bore, which opening is coaxial
with the throttle bore of the regulating member, the rubber disc being
deformed radially in dependence on the internal pressure in the spray
container so that the through-flow cross-section of the throttle bore
is reduced with increasing internal pressure. With decreasing internal
pressure, the constriction of the bore is correspondingly less and thus
the through-flow cross-section is greater. As the through-flow is a
function of the internal pressure and the through-flow cross-section,
it remains substantially constant, independently of the internal
pressure. However rubber-elastic material has the property that it
swells when it comes into contact with certain fluids, for example
grease-containing or oily fluids, as are frequently contained in spray
cans of that kind. In addition, the nominal dimensions of rubber-
elastic components cannot be maintained with close tolerances in
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manufacture, quite apart from the fact that they are dependent on
temperature and alter in the course of time, due to ageing phenomena.
As however the endeavour is to keep the through-flow cross-
section very small, for example about 0.2 mm2, in order to avoid
unnecessary consumption of the product contained in the spray
container, the through-flow rate is dependent to a considerable degree
on the nominal dimensions of the regulating member being accurately
maintained.
The invention is based on the problem of providing an actuating
fitment of the general kind set forth, in which the through-flow rate,
with the delivery valve open, is maintained with a higher degree of
accuracy.
In accordance with the invention that problem is solved in that
the regulating member is displaceable by the internal pressure of the
spray container against spring force over the intake opening of the
transverse bore until reaching an abutment which stops the regulating
member in a position in which it blocks the major part of the intake
opening, and that the regulating member is made from substantially
rigid material.
In that construction the regulating valve and the intake opening
of the transverse bore form a through-flow regulating valve which keeps
the through flow substantially constant, independently of the internal
pressure. The throttle bore in the regulating valve also contributes,
even if only to a slight degree, to keeping the through flow constant,
because with a high internal pressure it affords a somewhat higher
through-flow resistance than at a lower internal pressure, so that that
already ensures a certain degree of constancy of the through flow,
which is independent of the internal pressure. ~Irthermore, the
throttle bore already eliminates from the outset an excessively high
rate of discharge, upon actuation of the delivery valve. As is already
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the case hitherto, there is no need of an additional housing for the
through-flow regulating valveO The regulating member can be made from
comparatively hard plastics rnaterial which is substantially resistant
to ageing and which is insensitive in relation to the product contained
in the spray container.
It is preferably provided that the intake opening of the
transverse bore is formed as an axial slit, in the form of a rectangle.
That arrangement provides for linear dependency of the through-flow
cross-section of the intake opening on the internal pressure, and thus
provides for an even higher degree of constancy in the through flow.
The invention and developments thereof are described in greater
detail hereinafter with reference to the drawing showing a preferred
embodiment, in which:
Figure 1 is a view in axial section through an actuating fitment
according to the invention, with a low internal pressure in the spray
container,
Figure 2 is a view in vertical section in a plane perpendicular
to the sectional plane in Figure 1,
Figure 3 shows the same sectional view as Figure 1, but at a low
internal pressure in the spray container,
Figure 4 is a rear view of an insert of the actuating fitment,
and
Figure 5 is a section taken along line V-V in Figure 4.
The illustrated actuating fitment serves for the actuation of a
delivery valve of a spray container (not shown) containing a product
which is capable of flow and which is exposed to a gas pressure. The
actuating fitment is approximately in the form of a cap with a coaxial
inner tube 1 which delimits an axial bore 2. The tube 1 is fitted onto
a valve shank of the delivery valve, which shank forms a part of the
delivery duct of the spray container, so that the tube is connected
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thereto by a friction locking effect. By depressing the valve shank by
means of the actuating fitmen-t, the delivery valve is opened in
conven-tional manner so that the product flows out through the delivery
duct under the gas pressure obtaining in the spray container. In the
vicinity of the upper end of the axial bore 2, a transverse bore 3
leads to a discharge nozzle 4. A regulating member 5 is snugly fitted
in the axial bore 2 and is axially displaceable therein. It is in the
form of a circular cylinder with a central transverse wall 6 in which
there is a coaxial throttle bore 7. A coil spring 8 is arranged
between the transverse wall 6 and the upper end of the axial bore 2
which is in the form of a blind bore. The regulating member S is
displaceable by the internal pressure in the spray container, against
the force of the coil spring 8, over the intake opening 9 of -the
transverse bore 3, until encountering an abutment lO which stops the
regulating m~nber 5 in a position in which it blocks the major part of
the intake opening 9. The intake opening 9 of the transverse bore 3 is
formed as an axial slit in the form of a rectangle (see Figure 2). The
abutment lO is divided into a plurality of radial and axial projections
by substantially V-shaped interruptions 11. From the intake opening 9,
the transverse bore 3 enlarges in the form of flat surfaces which are
approximately semi-elliptical in side view, to a round cross-section.
The transverse bore 3 co~municates with an annular groove 12 in
to which a substantially cap-shaped insert 13 is inserted with its
peripheral wall, in such a way that the latter bears sealingly against
the radially outward wall of the annular groove 12 and is at a spacing
relative to the radially inward wall, so that accordingly a further
annular groove 14 remains free.
As Figures 4 and 5 more clearly show, in the middle of its
bottom the insert 13 has a depression 15 which is initially of a
circular-cylindrical configuration and which then tapers conically
towards the nozzle 4. In addition, provided in the bottom of the
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insert 13 are grooves 16 which converge substantially tangentially from
the peripheral wall of the insert 13 to the central depression 15, the
grooves being disposed at equal angular spacings.
A projection 17 which forms the radially inward wall of the
annular groove 12 (see Figure 1) defines on the one hand a swirl
chamber together with the depression 15 in the insert 13 and on the
other hand, together with the grooves 16, ducts which at their wider
ends communicate with the annular groove 14.
The actuating fitment is then provided with stiffening ribs 18
between its peripheral wall and the tube 1.
In order to open the delivery valve of the spray container, the
user presses with the finger against the slightly concave knurled
actuating surface of the actuating fitment. The product which is then
urged out of the spray container by the conpressed gas flows through
the axial bore 2, the throttle bore 7, the opening 9, the transverse
bore 3, the annular groove 12, the annular groove 14, the grooves 16,
the depression 15 and the nozzle 4 to the exterior. In that situation
it urges the regulating member 5 against the force of the coil spring 8
(upwardly) towards the intake opening 9. In that arrangement the coil
spring 8 is of such a size that, when the spray container is full and
at maximum internal pressure, the regulating member 5 is immediately
pressed to a position of bearing against the abutment lO, as shown in
Figure 3. When the regulating member 5 is in that position, the
product can nonetheless issue because the intake opening 9 is not
co~pletely closed off by the regulating member 5. However the throttle
bore 7, the small through-flow cross-section whlch still remains in the
opening 9 and finally the nozzle 4 which also acts as a throttle cause
a corresponding throttling action in relation to the through flow.
'rhat ensures that an excessively large amount of product cannot be
sprayed, in an undesirable fashion. Nonetheless substantially fine
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atomisation of the product is guaranteed, in particular due to swirling
of the product in the depression 15 in the insert 13 with the
propellent gas and the air.
If the internal pressure decreases due to repeated actuation of
the spray container, the coil spring 8 presses the regulating member 5
correspondingly further back against the internal pressure so -that the
free through-flow cross-section of the intake opening 9 is
correspondingly increased and thus the through flow is still kept
constant. In the position of the regulating member 5 shown in Figures
1 and 2, the container is substantially emptied and the internal
pressure is accordingly very low, so that the regulating member 5
completely opens the intake opening 9 and discharge of the remaining
product is throttled only by the throttle bore 7 and the nozzle 4.
