[0001] The invention is related to finger operated spray pumps for spraying aerosol products
by means of an atomiser arrangement. In detail the invention has as a starting point
a finger operated spray pump according to the generic part of claim 1.
[0002] Conventional aerosol finger operated spray pumps produce pressures of typically 4
bar by means of a cylinder/piston-arrangement. Those pumps operate a pressures of
much less than 10 bar anyway and do not lend themselves to higher pressures, as the
cylinder/piston-valve arrangement is moulded in thin plastics. However, in the prior
art it is understood that higher pressures cannot be achieved anyway, because the
average operating force provided by a finger on the hand of an operator will normally
be around 10 N and will even in the extreme not exceed 30 N.
[0003] Because of the low pressure generated in the cylinder/piston-arrangement of prior
art finger operated spray pumps the liquid to be atomised must be of low viscosity.
This means that large quantities of solvent such as alcohol and water are required
in the formulation of the liquid to lower the viscosity of the liquid. The high-level
solvent formulations of liquid used in conventional aerosol finger operated spray
pumps lead to sprays that are recognized by the user as "wet". Reducing the amount
of solvent means that the liquid becomes more viscous and more difficult to be sprayed.
In order to increase the pressure in the spray pump a mechanical advantage linkage
is required so that the force of the finger which is available can be transferred
to a higher pressure. This, however reduces the piston stroke in comparison with the
stroke length of the finger itself.
[0004] The object of the present invention is to provide a finger operated spray pump system
that is capable of atomising small doses of liquid in order to produce a "dry" spray
of liquid, i. e. a spray of liquid using much less solvent than prior art aerosol
finger operated spray pumps.
[0005] The above mentioned problem is met by a finger operated spray pump with the features
of the generic part and in addition comprising the features of the characterizing
part of claim 1. It has been realized according to the invention that a mechanical
advantage linkage to increase the finger force can be avoided if the diameter of the
cylinder/piston-system is reduced. A smaller diameter of the piston leads to a higher
pressure which is obtainable by the spray pump. However, the nozzle-diameter of the
atomiser must be adapted to the piston diameter which is done according to the corresponding
feature of the main claim. Finally, the operating pressure above 10 bar can be obtained
only if the parts of the spray pump are manufactured from materials and in a way to
withstand those elevated operating pressures.
[0006] Preferred features of the finger operated spray pump can be obtained from the sub
claims. The piston stroke according to claim 2 is adapted to the usual and comfortable
stroke length of the original finger stroke of a person using the finger operated
spray pump.
[0007] The liquid dose per spray stroke according to claim 3 is preferable for many kinds
of applications like perfume application.
[0008] It is particularly advantageous that the piston be made as a hollow piston and thus
having the passageway means formed into the hollow piston. This is advantageous for
both variants with the piston fixedly attached to the liquid reservoir (claim 4) or
fixedly attached to the actuator (claim 5). Preferred internal piston diameters are
given in claim 6 and the preferred embodiment of the hollow piston as a metal capillary
tube is the subject of claim 7. The use of a metal capillary tube as a hollow piston
simultaneously forming the passageway means is perfectly adapted to a high viscosity
perfume oil as a preferred liquid for such finger operated spray pump.
[0009] There are a number of optional features to be realized in the spray pump like a filter
to protect the atomiser (claim 11), a second one way valve means to prevent air ingress
into the cylinder (claim 12) and an air vent means on a rigid liquid reservoir to
allow pressure equalization in the liquid reservoir (claim 14).
[0010] An interesting alternative to a rigid liquid reservoir may be a collapsible bag directly
connected to the passageway means, perhaps within an outer more rigid protecting means
(claim 15).
[0011] The present invention relates to a finger operated spray pump that generates aerosol
sprays of low doses with relatively small particles. It is ideally suited for formulations
of liquid with a substantially reduced amount of solvent. The sprays generated give
a "dry" feeling. They are well suited for applications such as perfumes, bodysprays,
hairsprays and other surface or space sprays.
[0012] Now, preferred embodiments of the invention will be described by way of examples
with references to the drawings. In the drawings
- Fig. 1
- shows schematically a first embodiment of a finger operated spray pump with a rigid
liquid reservoir and a dip tube,
- Fig. 2
- shows a modification of Fig. 1 with a one way valve means behind the atomiser,
- Fig. 3
- shows the same spray pump as Fig. 1 now with a one way valve means and a filter behind
the atomiser,
- Fig. 4
- shows a second embodiment with a liquid reservoir in the form of a collapsible bag
contained in an outer protective housing,
- Fig. 5
- shows a third embodiment similar to the embodiment of Fig. 1, but the atomiser in
line with the cylinder in the actuator,
- Fig. 6
- shows a fourth embodiment with a hollow piston attached to the actuator and a cylinder
fixedly attached to the liquid reservoir.
[0013] Fig. 1 shows a first embodiment of the invention which is a finger operated spray
pump. This finger operated spray pump is comprising a liquid reservoir 1, which here
is in the form of a rigid container, intended to contain a supply of liquid 2. A cylinder
3 contains a pump volume 4 of liquid. The cylinder 3 is connected at one end to an
atomiser 5 and is intended to contain a portion of liquid from the reservoir 1, a
part of which is to be ejected through the atomiser 5 in a spray stroke.
[0014] The atomiser 5 may be of the swirl chamber type with a swirl chamber in front of
the nozzle exit. However, it may be of a double jet impender type or of any other
type realizing a mechanical brake up nozzle character. Ideas for such atomiser 5 can
be found for example in DE 101 54 237 A1. However, the atomiser 5 may as well produce
a jet of liquid if a specific requirement has to be met.
[0015] Fig. 1 shows that a piston 6 is sealingly mounted within the cylinder 3 and is movable
within and relative to the cylinder 3 in the spray stroke. The volume within the cylinder
3 is reduced and a corresponding amount of the liquid in the pump volume 4 of the
cylinder 3 is ejected through the atomiser 5. In a return stroke the piston 6 is movable
within and relative to the cylinder 3 such that the volume within the cylinder 3 is
increased and a corresponding amount of the liquid is drawn in from the liquid reservoir
1 into the cylinder 3. Fig. 1 shows the position of the parts of this embodiment at
the end of the return stroke, eventually the beginning of the spray stroke.
[0016] A passageway means 7 is connecting the cylinder 3 with the supply of liquid 2 in
the liquid reservoir 1. A one way valve means 8 at the passageway means 7 allows a
flow of liquid only from the supply of liquid 2 into the cylinder 3 but not in the
opposite direction. The actuator 9 has the atomiser 5 mounted at right angles to the
cylinder 3 and connected to the cylinder 3 by way of a short connecting duct 3'.
[0017] A finger operated actuator 9 is indicated in Fig. 1 and a finger tip is schematically
indicated there as well. By means of the force of the finger tip the actuator 9 is
displaceable relative to the liquid reservoir 1 in the spray stroke, i. e. downwards
in Fig. 1, and relative to the liquid reservoir 1 in an opposite direction in the
return stroke (upwards in Fig. 1, Fig. 1 showing the end of the return stroke). The
displacement of the actuator 9 induces the movement of the piston 6 relative to the
cylinder 3 and, in the spray stroke, the ejection of the liquid 2 within the pump
volume 4 through the atomiser 5. The return stroke is induced by a return spring force.
In the embodiment of Fig. 1 the return spring force is provided by a return spring
10 displayed here as a coil spring.
[0018] The piston 6 is sealingly mounted within the cylinder 3 so that a pressure build
up can take place in the cylinder 3 on the spray stroke. In Fig. 1 the seal is indicated
as a ring seal 6' schematically. However, the seal between piston 6 an cylinder 3
may as well be a solid seal mounted at the piston 6 or a simple gap seal realized
by an extremely small gap between piston 6 and cylinder 3 having a sealing characteristic
for a liquid 2 of sufficient viscosity.
[0019] According to the invention the outer diameter of the piston 6 and the corresponding
inner diameter of the cylinder 3 is between 0,5 mm and about 4,0 mm, preferably between
about 1,0 mm and about 3,0 mm, most preferably between about 1,5 mm and about 2,5
mm. The nozzle-diameter of the atomiser 5 is between 15 µm and 150 µm, preferably
between about 30 µm and about 100 µm. The operating pressure within the cylinder 3
during the spray stroke with average finger force is between 10 bar and 400 bar, preferably
between about 40 bar and about 200 bar, most preferably between about 50 bar and about
100 bar. The atomiser 5, the cylinder 3, the piston 6 and the one way valve means
8 are manufactured from materials and in a way to withstand the elevated operating
pressure.
[0020] In the present, and preferred, embodiment the piston stroke is between 2 and 30 mm,
preferably between about 15 mm and about 20 mm, which is comfortably adapted to the
usual stroke of a finger of a person using the spray pump.
[0021] As explained above, this finger operated spray pump has the advantage that low doses
of high viscosity liquid with a low amount of solvent can be sprayed. Preferably the
liquid dose per spray stroke is between 5 µl and 300 µl preferably between about 10
µl and about 100 µl, most preferably between about 20 µl and about 50 µl.
[0022] Fig. 1 shows a substantially preferred embodiment in that the piston 6 is fixedly
attached to the liquid reservoir 1 and is made as a hollow piston simultaneously forming
the passageway means 7 connected at one end directly or via a dip tube 11 to the supply
of liquid 2 and at the other end to the cylinder 3. In fact the piston 6 is fixedly
attached to the liquid reservoir 1 whereas the cylinder 3 and the atomiser 5 are arranged
within the actuator 9. The actuator 9 with cylinder 3 and atomiser 5 in total is moved
against the return spring force of the return spring 10 from the position in Fig.
1 downwards in the spray stroke towards the liquid reservoir 1. The passageway means
7 is integrated into the piston 6 itself, the piston 6 is a hollow piston.
[0023] In a preferred embodiment the internal diameter of the hollow piston 6 is between
about 0,2 mm and about 3,0 mm, preferably between about 0,5 mm and about 1,0 mm. In
a particularly advantageous embodiment the hollow piston 6 is made as a metal capillary
tube.
[0024] In order to withstand the elevated operating pressures in a preferred embodiment
the body of the actuator 9 is made from metal, preferably aluminium, or from highly
pressure resistant plastic. Even the capillary tube may be made from a specifically
selected plastic.
[0025] The one way valve means 8 in the embodiment of Fig. 1 is mounted at the inlet end
of the passageway means 7, i.e. in this embodiment the inlet end of the hollow piston
6. However, an alternative position may be the outlet end or a position between the
inlet end and the outlet end. Specific positions of the one way valve means 8 for
a high pressure spray pump can be obtained from DE 195 36 902 A1. As a conventional
solution, however, the passageway means 7 can be equipped at its inlet end with an
additional check valve (ball valve).
[0026] Fig. 6 shows an alternative embodiment of an otherwise very similar finger operated
spray pump. The same parts of the spray pump as in Fig. 1 are identified with the
same reference numbers and need no additional explanation. However, here the piston
6 is fixedly attached to the actuator 9 and is made as a hollow piston simultaneously
forming connecting means 13 connecting the cylinder 3 with the atomiser 5. Here the
cylinder 3 is fixedly attached to the liquid reservoir 1 and the piston 6 is fixedly
attached to the actuator 9.
[0027] A third construction is not displayed in the drawings. In this the cylinder 3 is
fixedly connected to the reservoir 1 via the passageway means 7 and the valve means
8. The cylinder 3 may be of T-form with three arms respectively connected to the reservoir
1, the atomiser 5 and the sealingly mounted piston 6. The actuator 9 has a solid piston
6 in addition to the return spring 10. This is more a traditional construction of
such a cylinder-piston-assembly.
[0028] Fig. 2 shows the same spray pump as Fig. 1, but in addition shows that a filter 14
is provided between the cylinder 3 and the atomiser 5 to protect the atomiser 5.
[0029] Fig. 3 shows the same spray pump as Fig. 2, but in addition that a second one way
valve means 15 is provided between the atomiser 5 and the cylinder 3 preventing air
in grass via the atomiser 5 into the cylinder 3 during the return stroke.
[0030] All Fig. 1, 2, 3 show the liquid reservoir 1 as a rigid bottle with the passageway
means 7 / piston 6 fixedly connected thereto, in particular to a closure 12 of the
reservoir 1 which is schematically shown in Fig. 1, 2, 3.
[0031] An air vent means 16 is disclosed for the embodiment with rigid reservoir 1 as shown
in Fig. 1, 2, 3 as a valve with flexible lip means. Also the closure 12 of the reservoir
1 can integrate some means that allow air to enter for pressure equalization in the
liquid reservoir 1. The air vent means 16 may be a mechanically operated one way valve
opened by a corresponding operating formation on the actuator 9 during the last leg
of the spray stroke.
[0032] Fig. 4 shows a different embodiment which is otherwise similar to Fig. 3, but with
a liquid reservoir 1 which is not a rigid bottle but is a collapsible bag directly
connected to the passageway means 7. This collapsible bag as liquid reservoir 1 as
such is mounted within an outer protective housing 17 which itself is closed by a
closure 12, the closure 12 again carrying the passageway means 7 / piston 6.
[0033] The outer protective housing 17 has an air vent means 16 which allows entry of air
into the outer protective housing 17 following the strokewise emptying of the collapsible
bag.
[0034] The liquid reservoir 1 in the form of a collapsible bag may be of a laminated type
to prevent unwanted ingress of air (oxygen). A rigid reservoir 1 may be a long tube
small enough in diameter to prevent air bubbles forming within the liquid.
[0035] Fig. 5 shows a finger operated spray pump otherwise similar to Fig. 1 but with the
atomiser 5 in line with the cylinder 3 and its pump volume 4. Finger pads 18 can be
seen at the sides of the atomiser 5.
[0036] The finger operated spray pump may be used upside down even with a rigid reservoir
1 so that no dip tube 11 and only a short passageway means 7 is necessary.
[0037] To operate the finger operated spray pump according to the invention, explained with
regard to Fig. 1, finger pressure is applied to the top of the actuator 9. Liquid
within the pump volume 4 of the cylinder 3 is forced under pressure through the connecting
duct 3' and the atomiser 5 creating a spray outside of the atomiser 5. The mass mean
particle diameter of the spray produced like this is between 5 and 100 µm.
[0038] The one way valve means 8 prevents liquid from returning to the reservoir 1 during
spraying. When the finger pressure is removed from the actuator 9 the return spring
10 returns the actuator 9 to its normal position (this is the return stroke). In doing
so liquid 2 is sucked up from the liquid reservoir 1 through the dip tube 11 and the
passageway means 7 into the pump volume 4 in the cylinder 3. Another spray stroke
is prepared and can be initiated immediately.
[0039] If a spray stroke is intended only with a fresh volume of liquid 2 in the cylinder
3, there may be a fixing means 19 fixing the actuator 9 on the reservoir 1 in its
lower position (at the end of the spray stroke). Before activating the finger operated
spray pump this must be released for a first return stroke. Fig. 6 shows such fixing
means 19 as a holding clip.
1. Finger operated spray pump comprising
a liquid reservoir (1) intended to contain a supply of liquid (2),
a cylinder (3) connected at one end to an atomiser (5) and intended to contain a portion
of liquid from the reservoir (1), a part of which is to be ejected through the atomiser
(5),
a piston (6) sealingly mounted within the cylinder (3) and movable within and relative
to the cylinder (3) in a spray stroke such that the volume within the cylinder (3)
is reduced and a corresponding amount of the liquid in the cylinder (3) is ejected
through the atomiser (5), and in a return stroke such that the volume within the cylinder
(3) is increased and a corresponding amount of the liquid is drawn from the supply
of liquid (2) into the cylinder (3),
a passageway means (7) connecting the cylinder (3) with the supply of liquid (2) in
the liquid reservoir (1),
a one way valve means (8) at the passageway means (7) allowing a flow of liquid only
from the supply of liquid (2) into the cylinder (3),
a finger operated actuator (9) displaceable by finger pressure relative to the liquid
reservoir (1) in the spray stroke and, preferably by a return spring force, relative
to the liquid reservoir (1) in an opposite direction in the return stroke,
wherein the displacement of the actuator (9) induces the movement of the piston (6)
relative to the cylinder (3),
characterized in that
the outer diameter of the piston (6) and the corresponding inner diameter of the cylinder
(3) is between about 0,5 mm and about 4,0 mm, preferably between about 1,0 mm and
about 3,0 mm, most preferably between about 1,5 mm and about 2,5 mm,
the nozzle-diameter(s) of the atomiser (5) is between 15 µm and 150 µm, preferably
between about 30 µm and about 100 µm,
the operating pressure within the cylinder (3) during the spray stroke with average
finger force is between 10 bar and 400 bar, preferably between about 40 bar and about
200 bar, most preferably between about 50 bar and about 100 bar, and
the atomiser (5), the cylinder (3), the piston (6) and the one way valve means (8)
are manufactured from materials and in a way to withstand the elevated operating pressure.
2. Finger pump according to claim 1, characterized in that the piston stroke is between 2 and 30 mm, preferably between about 15 mm and about
20 mm.
3. Finger pump according to claim 1 or 2, characterized in that the liquid dose per spray stroke is between 5 µl and 300 µl preferably between about
10 µl and about 100 µl, most preferably between about 20 µl and about 50 µl.
4. Finger pump according to any one of the claims 1 to 3, characterized in that the piston (6) is fixedly attached to the liquid reservoir (1) and is made as a hollow
piston simultaneously forming the passageway means (7) connected at one end directly
or via a dip tube (11) to the supply of liquid (2) and at the other end to the cylinder
(3), wherein, preferably, the internal diameter of the hollow piston (6) is between
about 0,2 mm and about 3,0 mm, preferably between about 0,5 mm and about 1,0 mm, and/or
the hollow piston (6) is made as a metal capillary tube.
5. Finger pump according to any one of the claims 1 to 3, characterized in that the piston (6) is fixedly attached to the actuator (9) and is made as a hollow piston
simultaneously forming connecting means (13) connecting the cylinder (3) with the
atomiser (5), wherein, preferably, the internal diameter of the hollow piston (6)
is between about 0,2 mm and about 3,0 mm, preferably between about 0,5 mm and about
1,0 mm, and/or the hollow piston (6) is made as a metal capillary tube.
6. Finger pump according to any one of the claims 1 to 5, characterized in that the body of the actuator (9) is made from metal, preferably from aluminium or from
highly pressure resistant plastic.
7. Finger pump according to any one of the preceding claims except claim 5, characterized in that the piston (6) is fixedly attached to the liquid reservoir (1) and the cylinder (3)
and the atomiser (5) are arranged within or as part of the actuator (9).
8. Finger pump according to any one of the preceding claims except claim 4, characterized in that the cylinder (3) is fixedly attached to the liquid reservoir (1) and the piston (6)
is fixedly attached to the actuator (9).
9. Finger pump according to any one of the preceding claims, characterized in that a filter (14) is provided between the cylinder (3) and the atomiser (5) to protect
the atomiser (5), and/or a second one way valve means (15) is provided between the
atomiser (5) and the cylinder (3) preventing air ingress via the atomiser (5) into
the cylinder (3) during the return stroke.
10. Finger pump according to any one of the preceding claims, characterized in that the liquid reservoir (1) is a rigid bottle with the passageway means (7) fixedly
connected thereto, wherein, preferably, the rigid liquid reservoir (1) is provided
with an air vent means (16) to allow pressure equalization in the liquid reservoir
(1).
11. Finger pump according to any one of the claims 1 to 9, characterized in that the liquid reservoir (1) is a collapsible bag directly connected to the passageway
means (7).
12. Finger pump according to any one of the claims 1 to 11, characterized in that there is provided a fixing means (19) fixing the actuator (9) on the reservoir (1)
in its lower position and being releasable for a first return stroke before activating
the spray pump.