U.S. patent application number 10/589195 was filed with the patent office on 2007-07-19 for simplified metering pump.
Invention is credited to Antonio Gordillo Aubert, Santiago Julian Pidevall, Victor Ribera Turro.
Application Number | 20070164052 10/589195 |
Document ID | / |
Family ID | 46940654 |
Filed Date | 2007-07-19 |
United States Patent
Application |
20070164052 |
Kind Code |
A1 |
Julian Pidevall; Santiago ;
et al. |
July 19, 2007 |
Simplified metering pump
Abstract
A metering pump including a main body having a first surface, a
member for attachment to a bottle, an inlet valve, an elastomeric
head having a second surface, where both surfaces define a pumping
chamber, and a discharge valve having a valve seat and a moving
member adapted to move between a first closed position and a second
open position. The moving member extends from the head forming a
partition and is integral with the head. The first and second
surfaces are relatively movable therebetween causing pumping of a
liquid. When the moving member is in the first position and there
is a reduced pressure in the pumping chamber, the reduced pressure
then presses the moving member against the valve seat.
Inventors: |
Julian Pidevall; Santiago;
(Barcelona, ES) ; Ribera Turro; Victor;
(Barcelona, ES) ; Gordillo Aubert; Antonio; (Sant
Cugat del Valles, ES) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Family ID: |
46940654 |
Appl. No.: |
10/589195 |
Filed: |
July 19, 2005 |
PCT Filed: |
July 19, 2005 |
PCT NO: |
PCT/ES05/00404 |
371 Date: |
August 11, 2006 |
Current U.S.
Class: |
222/207 |
Current CPC
Class: |
B05B 11/3032 20130101;
B05B 11/306 20130101 |
Class at
Publication: |
222/207 |
International
Class: |
B65D 37/00 20060101
B65D037/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 20, 2004 |
ES |
P200402494 |
Claims
1. A metering pump comprising: (a) a main body having a first
surface, (b) first means for attachment to a bottle neck, (c)
second means for attachment of a dip tube, (d) an inlet valve, (e)
a head, where said head has a second surface facing said first
surface, and where said first surface and said second surface
define a pumping chamber, where said head is made from a material
having elastomeric properties adapted to be resiliently deformed by
a manually applied force and has an external actuation surface
adapted to be deformed by a user's finger, and (f) a discharge
valve at the outlet of said pumping chamber, where said discharge
valve includes a valve seat and a moving member adapted to move
between a first position, corresponding to said closed discharge
valve and in which said moving member contacts said valve seat, and
a second position, corresponding to said open discharge valve,
where said moving member extends from said head forming a
partition, where said moving member is integral with said head, and
where said first surface and said second surface are adapted to
perform a relative movement therebetween causing the pumping of a
liquid between said inlet valve and said discharge valve, wherein
when said moving member is in said first position, and there is a
reduced pressure in said pumping chamber, said reduced pressure
then exerts a force pressing said moving member against said valve
seat.
2. The pump of claim 1, wherein said partition is a flat
surface.
3. The pump of claim 1, wherein said partition is a cylindrical
surface.
4. The pump of claim 1, wherein said partition is a cylinder
surrounding said second surface.
5. The pump of claim 4, wherein said valve seat is formed by a
second also cylindrical partition disposed in said main body, where
said second partition surrounds said first surface.
6. The pump of claim 1, wherein said second surface is convexely
curved towards an outside of said pumping chambers, and is a
spherical cap.
7. The pump of claim 1, wherein said first surface has a concavely
curved portion towards an interior of said pumping chamber, and is
a spherical portion.
8. The pump of claim 7, wherein said curved portion and said second
surfaced make contact in a limit of the stroke followed by said
second surface during a pumping movement.
9. The pump of claim 8, wherein said curved portion has an external
rim that is convex towards the interior of said pumping
chamber.
10. The pump of claim 1, wherein said valve seat has a rounded
contact surface with said moving member.
11. The pump of claim 1, wherein said moving member has a contact
portion with said valve seat having a thickness tapering down
towards a free end thereof.
12. The pump of claim 1, having at least one column on said first
surface extending towards said second surface and which is disposed
at a portion proximate said discharge valve.
13. The pump of claim 12, wherein said at least one column has a
height such as to contact said second surface when said second
surface is in an extended position thereof.
14. The pump claim 1 further comprising: an attachment body
including said first attachment means, where said attachment body
is attached to said main body for relative displacement between an
open position and a closed position, and wherein said attachment
body includes a projection which, when said attachment body and
said main body are in the closed position, prevents said second
surface from performing said relative movement.
15. The pump of claim 14, wherein said projection is a tubular stem
surrounding said inlet valve.
16. The pump of claim 14, wherein said projection is hermetically
sealed against said second surface when said attachment body and
said main body are in said closed position.
17. The pump of claim 14, wherein said relative displacement is
greater than said relative movement.
18. The pump of claim 15, wherein said main body includes a first
annular lip forming a hermetic seal with the outer wall of said
tubular stem.
19. The pump of claim 18, wherein said main body includes a second
annular lip forming a hermetic seal with an annular partition
disposed in said attachment body, said annular partition
surrounding a ventilation hole.
Description
DESCRIPTION
[0001] 1. Field of the Invention
[0002] The invention relates to a simplified metering pump,
particularly a pump comprising: (a) a main body having a first
surface, (b) first means for attachment to a bottle neck, (c)
second means for attachment of a dip tube, (d) an inlet valve, (e)
a head, where the head has a second surface facing the first
surface, and where the first surface and the second surface define
a pumping chamber, where the head is made from a material having
elastomeric properties adapted to be resiliently deformed by a
manually applied force and has an external actuation surface
adapted to be deformed by a user's finger, and (f) a discharge
valve at the outlet of the pumping chamber, where the discharge
valve comprises a valve seat and a moving member adapted to move
between a first position, corresponding to the closed discharge
valve and in which the moving member contacts the valve seat, and a
second position, corresponding to the open discharge valve, where
the moving member extends from the head forming a partition, where
the moving member is integral with the head, and where the first
surface and the second surface are adapted to perform a relative
movement therebetween causing the pumping of a liquid between the
inlet valve and the discharge valve.
[0003] In the present description and claims, it is to be
understood that a material having elastomeric properties is any
material capable of being subjected to a resilient deformation
sufficient to fulfill the requirements of the invention,
particularly, capable of generating a pumping effect of a liquid
contained in a bottle. Thus, not only must the conventional
elastomeric materials be included in this group of materials, but
other plastics materials must also be included, such as for example
polypropylene, that, with an appropriate geometry, may be subjected
to considerable resilient deformation and may recover their initial
shape when the external force causing their deformation ceases.
[0004] 2. State of the Art
[0005] Various embodiments of metering pumps are known for a
plurality of applications. Metering pumps are frequently attached
to disposable liquid containers. In this sense, the cost of the
pump has to be very low, since it must not appreciably affect the
product total cost. On the other hand, apart from performing the
technical function of pumping the liquid, the metering pump
frequently has to have a particular aesthetic appearance, a fact
that often imposes serious geometrical limitations, which have to
be compatible with the correct working of the pump. In this sense,
there is a permanent need for developing new simplified metering
pumps, allowing for cost savings and limiting as little as possible
the aesthetic appearance it is wanted to confer on the pump.
[0006] In U.S. Pat. No. 3,820,689, published on Jun. 28, 1974,
there is described a metering pump of the type mentioned above.
Nevertheless, this pump has a number of drawbacks, particularly, it
is hard to obtain a good pumping effect with it.
SUMMARY OF THE INVENTION
[0007] The invention aims to overcome these drawbacks. This aim is
achieved with a simplified metering pump of the type first
mentioned above wherein when the moving member is in the first
position, and there is a reduced pressure in the pumping chamber,
the reduced pressure then exerts a force pressing the moving member
against the valve seat.
[0008] In fact, in this way it is possible to improve the pumping
effect. In the pump described in U.S. Pat. No. 3,820,689 mentioned
above, the discharge valve does not close optimally, because when
there is a reduced pressure in the pumping chamber, thanks to which
it is filled with liquid from the reservoir, the discharge valve is
then closed due only to the resilient forces of the head, which is
made from a material having elastomeric properties. Nevertheless,
the reduced pressure in the pumping chamber tends to open the
discharge valve, because the discharge valve has downstream the
atmospheric pressure of the external environment, whereby the
pressure differential acts against closing of the discharge valve.
Nevertheless, in the pump according to the invention, the moving
member is disposed such that the reduced pressure in the pumping
chamber forces the moving member against the valve seat. In this
way, the reduced pressure in the pumping chamber helps the
resilient force of the elastomeric head to keep the discharge valve
closed, namely, the resilient recovery force and the force due to
the reduced pressure in the pumping chamber act in the same
direction. In other words, the moving member of the discharge valve
has two faces, one of them oriented upstream (the inner face) and
the other one oriented downstream (the outer face). Thus, when the
discharge valve is closed, the moving member has the face oriented
upstream (the inner face) subject to the reduced pressure inside
the pumping chamber, while the face oriented downstream (the outer
face) is subject to the atmospheric pressure of the external
environment. Therefore, the pressure differential tends to move the
moving member in the upstream direction, pressing it against the
valve seat. This improves the closing of the discharge valve, which
prevents air from entering the pumping chamber and improves the
pumping effect of the pump.
[0009] Generally, the partition forming the moving member may have
any geometry, either flat, in the form of a cylindrical surface, in
the form of a spherical cap, undulated, etc. The only requirement
is that the force caused by the pressure difference (reduced
pressure in the pumping chamber and atmospheric pressure at the
outlet of the discharge valve) should press the partition against
the valve seat, which consists basically of a frame against which
the perimeter of the partition will bear. Nevertheless, the
partition is preferably a flat surface or a cylindrical surface.
Specifically, the cylindrical surface allows it to be housed better
in the ensemble of the pump, in which the majority of the surfaces
in its surroundings are also cylindrical.
[0010] A preferred embodiment of the invention is obtained when the
partition is a cylindrical surface extending over a certain
relatively small angle, generally less than 90.degree. and even
less than 45.degree.. Thus, the curved shape of the partition does
not make it excessively rigid so that it can move by flexure.
Nevertheless another preferred form of the invention is obtained
when the partition is a cylindrical surface extending over
360.degree., i.e. such as to form a cylinder surrounding the second
surface. In this case, the discharge valve communicates the pumping
chamber with an annular discharge conduit surrounding the entire
pumping chamber. In this case the valve seat is preferably formed
by a second also cylindrical partition and is disposed in the main
body such that the second partition surrounds the first surface.
Thus, the partition (which is the moving member of the discharge
valve) bears against the second partition (which is the frame or
fixed member of the discharge valve) when the discharge valve is
closed. When the liquid contained in the pumping chamber is
compressed, the cylindrical partition bends totally outwardly
allowing the liquid to flow to the annular discharge conduit.
[0011] The second surface is advantageously convexly curved towards
the exterior of the pumping chamber and preferably is a spherical
cap. In fact, this geometry optimizes the pumping chamber for a
minimum surface of the head. Furthermore, it has a good resilient
recovery force, causing the external actuation surface to return to
its original geometry, overcoming the reduced pressure generated
inside the pumping chamber. Alternatively it is possible to make
the second surface flat. In this case, the external actuating
surface of the head does not project above its surroundings, which
allows for the design of pumps, which, for example, may be piled on
the head.
[0012] The first surface is advantageously provided with a portion
concavely curved towards the interior of the pumping chamber, and
it is preferably a spherical portion. As in the case commented
above, this geometry optimizes the volume of the pumping chamber
with regard to the area thereof. But this geometry is particularly
effectively adapted to the shape to be assumed by the second
surface when deformed by a finger.
[0013] Furthermore, it is particularly advantageous for the curved
portion and the second surface to make contact in the limit of the
stroke followed by the second surface during a pumping movement. In
this way the residual volume of the pumping chamber is minimized,
whereby the size of the pump may be optimized. It is likewise
particularly advantageous for the curved portion to have an outer
rim that is convex towards the inside of the pumping chamber. This
outer rim serves as a support for the second surface, allowing it
to deform more "smoothly", avoiding the formation of major
deformations (and, therefore, major stresses) at the edge of the
second surface, i.e. in the portion where the head member which
moves and the head member which is attached to the rest of the pump
are connected. Furthermore, the outer rim serves to reduce even
more the residual volume of the pumping chamber. Finally, it also
serves to facilitate the recovery of the second surface to its
original position (extended position).
[0014] The valve seat preferably has a rounded contact surface with
the moving member. This geometry improves the seal between the
partition and the valve seat, because when the partition is
deformed by the pressure differential between the pumping chamber
and the outside, this deformation causes the support surface
between the partition and the frame to be increasingly greater,
whereby the force tending to close the partition is distributed
over a larger area. For the same reason, the moving member
advantageously has a contact portion with the valve seat that is
increasingly thinner towards its free end.
[0015] In the pump according to the invention the head has two
members, the external actuation surface with its corresponding
second surface and the moving member of the discharge valve
defining a partition, which have totally different functions.
Nevertheless, the head is an integral unit and is made from an
elastomeric material, whereby the deformation undergone by the head
during pumping, which should strictly be located on the external
actuation surface, may really extend to affecting the moving member
of the discharge valve, influencing the closing thereof. It is
therefore advantageous for the pump to have at least one column on
the first surface extending towards the second surface and disposed
in a portion proximate the discharge valve. In fact, in this way
the column acts as a stop such that the deformation of the head is
stopped by the column and the head portion where the moving member
of the discharge valve is disposed is not affected. There are
advantageously two columns, such that there is a broad passage
between them for the pumped liquid. The columns preferably have
such a height that they contact the second surface when the second
surface is in its extended position. In this way, immediately the
deformation of the external actuation surface starts, the columns
perform their support function and the portion of the head where
the moving member of the discharge valve is located is not deformed
in any way due to the deformation of the external actuation
surface.
[0016] The pump according to the invention may have a main body
which is a single part comprising first attachment means to the
neck of the bottle, second attachment means of a dip tube, and the
seat of an inlet valve. This solution reduces the number of
components of the pump to a minimum.
[0017] Another preferred embodiment of the invention is obtained
when the pump has, apart from a main body, an attachment body
comprising the first attachment means, where the attachment body is
attached to the main body with the possibility of a relative
displacement between an open position and a closed position and
wherein the attachment body comprises a projection which, when the
attachment body and the main body are in the closed position,
prevents the second surface from performing said relative movement.
In fact, although this variant of the pump has one more part than
the previous one, in this way, it is possible to have a sealing
mechanism preventing discharge of liquid by inadvertent pumping,
for example during the transportation and handling of the pump.
[0018] Preferably the projection is a tubular stem surrounding the
inlet valve. The projection thus serves also to close the passage
of the inlet valve, which also prevents liquid spillages caused by
over-pressurizing the container and/or placing it upside down. This
is achieved preferably by having the projection hermetically sealed
against the second surface when the attachment body and the main
body are in the closed position.
[0019] Advantageously, the relative displacement is greater than
the relative movement. There is thus ensured, on the one hand, that
the projection makes contact with the second surface when it is in
the closed position and, on the other hand, that the second surface
does not contact the projection when the pump is in its open
position but when the second surface is in the limit of deformation
due to the pumping movement. There may thus be included lips on the
second surface improving the seal with the projection when the pump
is in the closed position, without running the risk of these lips
contacting the projection during a pumping movement, since
otherwise the risk would be run of the second surface becoming
blocked with the projection and not being able to return to its
initial position (extended position).
[0020] The main body preferably comprises a first annular lip
acting as a seal with the outer wall of the tubular stem.
[0021] The main body advantageously comprises a second annular lip
acting as a seal with an annular partition disposed in the
attachment body when the pump is in the closed position, where the
annular partition surrounds a ventilation hole. There are thus
avoided possible liquid losses through the ventilation hole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Further advantages and features of the invention will become
evident from the following description in which preferred
embodiments of the invention are described without any limiting
nature, with reference to the accompanying drawings, in which:
[0023] FIG. 1 is longitudinal section view of a pump according to
the invention, in the open position.
[0024] FIG. 2 is a cross section view of the pump of FIG. 1 in the
closed position.
[0025] FIG. 3 is a longitudinal section view on the line III-III of
the attachment body of the pump of FIG. 1.
[0026] FIG. 4 is an elevation view of the attachment body of FIG.
3.
[0027] FIG. 5 is a top plan view of the attachment body of FIG.
3.
[0028] FIG. 6 is a bottom plan view of the head of the pump of FIG.
1.
[0029] FIG. 7 is a longitudinal section view of the head of FIG.
6.
[0030] FIG. 8 is a bottom perspective view of the head of FIG.
6.
[0031] FIG. 9 is a longitudinal section view of the main body of
the pump of FIG. 1.
[0032] FIG. 10 is a front elevation view of the main body of FIG.
9.
[0033] FIG. 11 is a top plan view of the main body of FIG. 9.
[0034] FIG. 12 is a top perspective view of the main body of FIG.
9.
[0035] FIG. 13 is a top perspective view of the pump of FIG. 1 in
the open position.
[0036] FIG. 14 is a top perspective view of the pump of FIG. 2 in
the closed position.
[0037] FIG. 15 is a longitudinal section view of the pump of FIG. 1
with the second surface deformed.
[0038] FIG. 16 is a longitudinal section view of a second pump
according to the invention.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0039] FIG. 1 shows a simplified metering pump according to the
invention. It comprises a main body 1, a attachment body 3, a head
5 and a ball 7 which is the moving member of a inlet valve 9
disposed in the attachment body 3. The main body 1 has a first
surface 11 facing a second surface 13 disposed in the head 5.
Between these two there is defined a pumping chamber 17. The head 5
is made from a material having elastomeric properties and has an
external actuation surface 15 adapted to be deformed by a user's
finger between an extended position, corresponding to the rest
position shown in FIG. 1, and a deformed position, corresponding to
the end of pumping position shown in FIG. 15. The external
actuation surface 15 coincides substantially with the second
surface 13, bearing in mind only that the external actuation
surface 15 is the one physically in contact with the outside and
with the user's finger and the second surface 13 is the surface
facing the inside of the pump, concretely towards the pumping
chamber 17.
[0040] FIG. 1 also shows a dip tube 19 attached at one end to the
attachment body 3 by second attachment means formed substantially
by a cylindrical projection adapted to house the dip tube 19
therein. The dip tube 19 has the other end thereof dipped in the
liquid to be pumped contained in a bottle, not shown in the drawing
figures.
[0041] The attachment body 3 is provided with first attachment
means consisting of a threaded portion 21 adapted to be attached to
a bottle neck, it is also provided with protrusions 23 housed in
helical grooves 25 disposed in the main body 1 so that when the
main body 1 is rotated relative to the attachment body 3, apart
from the rotary movement there is a translation movement along the
longitudinal axis of the pump, whereby there is achieved a relative
displacement between the attachment body 3 and the main body 1
between an open position, as shown in FIG. 1, and a closed
position, as shown in FIG. 2. The attachment body 3 has,
furthermore, a projection in the form of a tubular stem 27 that
surrounds the inlet valve 9 and extends along the longitudinal axis
towards the head 5.
[0042] When the pump is in the closed position the tubular stem 27
is inserted inside the pumping chamber 17 up to touching the head
5, precisely the second surface 13. The second surface 13 is
provided with a second cylindrical projection 29 that improves the
seal between the second surface 13 and the tubular stem 27. Thus
the inlet valve 9 is completely closed such that the liquid
contained in the bottle cannot flow through the inlet valve 9 and
be poured outside although the inside of the bottle is
overpressurized and/or the bottle is placed upside down.
[0043] The main body 1 has a first annular lip 31 sealing against
the outside wall of the tubular stem 27. In this way, the pumping
chamber 17 is sealed without any possibility of the liquid held
therein flowing inside the main body 1.
[0044] The pump is provided with ventilation hole 33 disposed in
the attachment body 3 allowing air to enter the bottle and replace
the pumped liquid. The area of contact between the protrusions 23
and the helical grooves 25 is not hermetic, so that the air can
flow inside the main body 1 and inside the bottle through the
ventilation hole 33. The attachment body 3 is provided with an
annular partition 35 surrounding the ventilation hole 33, and the
main body 1 has a second annular lip 37 which seals against the
annular partition 35 when the pump is in its closed position. In
this way there is prevented possible leaks of the liquid from the
bottle through the ventilation hole 33.
[0045] The head 5 is made from a material having elastomeric
properties. It comprises a connecting portion 39 with the main body
1. This connexion may be by any conventional means, such as
welding, adhesive bonding, etc. The head 5 is also provided with a
partition 41 that is the moving member of a discharge valve 43.
This discharge valve 43 is provided with a valve seat 45 disposed
in the main body 1. The partition 41 may be bent resiliently such
that it performs an approximate rotary movement around the
connecting portion between the partition 41 and the rest of the
head 5 between a first position, in which the discharge valve 43 is
closed, in which the partition 41 contacts the valve seat 45, and a
second position, in which the discharge valve 43 is open, in which
the partition 41 has flexed arcuately owing to the pressure of the
liquid contained in the pumping chamber 17 On FIGS. 6 through 8
this would be a flexing to the left).
[0046] As may be seen, the partition 41 shown in FIGS. 6 through 8
is a cylindrical surface extending over an angle of approximately
30.degree.. Nevertheless, this geometry may be different, as for
example the partition 41 may be flat, undulating, or any other
geometry. Likewise, its perimeter may be substantially rectangular,
but is may adopt other geometries, such as for example, oval. FIG.
16 shows another embodiment of a pump according to the invention.
In this case the partition 41 is a cylinder (i.e. a cylindrical
surface which extends over 360.degree.) that completely surrounds
the second surface 13. The partition 41 contacts a second partition
47 disposed on the main body 1 and defining the valve seat 45 of
the discharge valve 43. The second partition 47 surrounds the first
surface 11. In this way the liquid flows out of the pumping chamber
17 in all directions since the discharge valve 43 is annular. At
the exit of the discharge valve 43 there is a discharge channel 49,
which is also annular, and which leads the pumped liquid to the
discharge orifice. It may also be seen that in the pump of FIG. 16,
there is no attachment body as an independent part, but that the
main body 1 simultaneously forms the first surface 11, the first
attachment means (consisting again of a threaded portion 21), the
second attachment means (formed again by a projection adapted to
house therein the dip tube 19) and the seat of the inlet valve
9.
[0047] In the examples illustrated in the Figures, the second
surface 13 is a spherical cap. Nevertheless, it could also be a
flat disc-shaped surface closing the pumping chamber 17. Likewise,
the first surface 11 has a portion concavely curved towards the
interior of the pumping chamber 17, which is substantially
spherical in shape, although here again it could be flat or have
any other geometry. The only basic requirement is that a pumping
chamber 17 be defined between the first surface 11 and the second
surface 13 when the second surface 13 is in the extended position.
Nevertheless, as stated above, the spherical geometries are
advantageous. Additionally, the main body 1 has an external rim 51
convex towards the interior of the pumping chamber 17 and
surrounding the curved portion of the first surface 11.
[0048] The valve seat 45 of the discharge valve 43 has a rounded
surface 53 for contacting the partition 41 (which is the moving
member of the discharge valve 43). Further, the partition 41 is
provided with a portion 55 for contacting the valve seat 45 of the
discharge valve 43, concretely with the contact surface 53, the
thickness of which tapers down towards its free end. As stated
above, these two geometric solutions each improve the sealing of
the discharge valve 43.
[0049] The pump has two columns 57 projecting from the first
surface 11 and extending to practically touching the second surface
13 when the latter is in its extended position. Both columns 57 are
disposed at a portion proximate the discharge valve 43. As may be
seen in FIG. 15, these columns 57 prevent the head 5 from deforming
in the portion proximate the partition 41, namely, in the portion
proximate the discharge valve 43. In fact, what the columns 57 do
is delimit more clearly which is the external actuation surface 15
and the second surface 13 from what is the discharge valve 43.
Thus, when the external actuation surface 15 has been deformed, as
shown in FIG. 15, this deformation is prevented from extending to
the portion of the partition 41, which could cause incorrect
operation of the discharge valve 43.
[0050] FIG. 15 also shows how the curved portion of the first
surface 11 and the second surface 13 extend almost mutually
parallel to each other. With an appropriate design, it is possible
to achieve that these two surfaces make contact, whereby it is
possible to minimize the residual volume of the pumping chamber
17.
[0051] As may be seen in the pump example shown in FIG. 15, the
second cylindrical projection 29 of the second surface 13
practically makes contact with the upper end of the tubular stem
27, when the pump is in the open position and the second surface 13
is in the deformed position. One preferred embodiment of the
invention is obtained when the relative displacement effected by
the upper end of the tubular stem 27 when moving between the closed
position and the open position is greater than the relative
movement effected by the second cylindrical projection 29 on moving
the second surface 13 between the extended position and the
deformed position. In this way, when the pump is in the open
position, the second cylindrical projection 29 is prevented from
contacting the upper end of the tubular stem 27, thereby reducing
the risk of the second cylindrical projection 29 becoming jammed in
the upper end of the tubular stem 27 during a pumping movement.
[0052] In the embodiments shown, the partition 41 is always close
to the end of the external actuation surface 15 (which is a
spherical cap). Nevertheless, it is not necessary for this to be
so, but, for example, the part of the head 5 and of the main body 1
corresponding to the discharge valve 43 could extend towards the
discharge tube such that the partition 41 is further separated from
the pumping chamber 17 (for example, half way between the position
it occupies in FIG. 1 and the discharge orifice). This would allow
the effect of the deformation of the external actuation surface 15
on the partition 41 to be reduced also.
* * * * *