U.S. patent application number 15/749615 was filed with the patent office on 2018-08-09 for method for assembling a dispensing system for dispensing a fluid medium.
The applicant listed for this patent is Coster Technologie Speciali S.p.A.. Invention is credited to Adalberto Geier, Alfeo Tecchiolli.
Application Number | 20180222613 15/749615 |
Document ID | / |
Family ID | 61975946 |
Filed Date | 2018-08-09 |
United States Patent
Application |
20180222613 |
Kind Code |
A1 |
Geier; Adalberto ; et
al. |
August 9, 2018 |
METHOD FOR ASSEMBLING A DISPENSING SYSTEM FOR DISPENSING A FLUID
MEDIUM
Abstract
The invention provides a method for assembling a dispensing
system (1) for dispensing a fluid medium under pressure, the method
including: providing a valve cup (10) including a valve (50) and a
bag (100), the valve (50) configured to attach to an opening of the
bag (100), wherein the valve cup (10) is either formed from a first
plastic or includes a lining (70) formed from the first plastic;
inserting the valve (50) into the opening of the bag (100) and
fluidly sealing the bag (100) to the valve (50); providing a
container (30), the container (30) including an opening (32) and
suitable for storing a fluid medium under pressure and formed, at
least in part, from a second plastic; inserting the bag (100) into
the container (30) and positioning the valve cup (10) at the
opening (32) of the container (30); pressurising the internal
volume of the container (30); and welding the valve cup (10) to the
container (30) to thereby provide a seal between the valve cup (10)
and the opening (32) of the container (30).
Inventors: |
Geier; Adalberto;
(Villazzano, IT) ; Tecchiolli; Alfeo; (Meano,
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Coster Technologie Speciali S.p.A. |
Calceranica Al Lago (trento) |
|
IT |
|
|
Family ID: |
61975946 |
Appl. No.: |
15/749615 |
Filed: |
June 14, 2016 |
PCT Filed: |
June 14, 2016 |
PCT NO: |
PCT/EP2016/063571 |
371 Date: |
February 1, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65D 83/20 20130101;
B65B 7/2878 20130101; B65B 31/028 20130101; B65D 83/48 20130101;
B65D 83/425 20130101; B65D 83/38 20130101; B65B 31/003 20130101;
B65D 83/62 20130101 |
International
Class: |
B65B 31/02 20060101
B65B031/02; B65D 83/62 20060101 B65D083/62; B65D 83/38 20060101
B65D083/38; B65D 83/48 20060101 B65D083/48 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 4, 2015 |
EP |
15179629.9 |
Claims
1. A method for assembling a dispensing system for dispensing a
fluid medium stored under pressure, the method including: providing
a valve cup including a valve and a bag, the valve configured to
attach to an opening of the bag, wherein the valve cup is either
formed from a first plastic or includes a lining formed from the
first plastic; inserting the valve into the opening of the bag and
fluidly sealing the bag to the valve; providing a container, the
container including an opening and suitable for storing a fluid
medium under pressure and formed, at least in part, from a second
plastic; inserting the bag into the container and positioning the
valve cup at the opening of the container; pressurising the
internal volume of the container; and welding the valve cup to the
container to thereby provide a seal between the valve cup and the
opening of the container.
2. The method of claim 1, wherein the valve cup is formed from the
first plastic material, and the first plastic material is a
semi-crystalline polyester.
3. The method of claim 1, wherein the first plastic material has a
degree of crystallinity greater than 35%, preferably greater than
38%, when measured using differential scanning calorimetry.
4. The method of claim 1, wherein the first plastic material is
selected from the group consisting of: crystallised PET, PBT, PEN,
PEN/PET copolymers, or a blend of any of the foregoing; and the
second plastic material is a polyester, preferably PET.
5. The method of claim 1 wherein the container is entirely formed
from the second plastic material.
6. The method of claim 1, wherein the second plastic material is a
semi-crystalline polyester.
7. The method of claim 6, wherein the second plastic material has a
degree of crystallinity greater than 35%, preferably greater than
38%, when measured using differential scanning calorimetry.
8. The method of claim 7, wherein the second plastic material is
selected from the group consisting of: crystallised PET, PBT, PEN,
PEN/PET copolymers, or a blend of any of the foregoing, and the
first plastic material is a polyester, preferably PET.
9. The method of claim 1, wherein the valve cup is formed from a
metal or rigid material, and the valve cup includes the polyester
lining provided at at least a portion of the valve cup that faces
the container when assembled, wherein the polyester lining is
either held by the valve cup or is coated onto the valve cup.
10. The method of claim 1, wherein welding the valve cup to the
container includes welding the valve cup to the container by any
one of: friction welding, ultrasonic welding, and laser
welding.
11. The method of claim 1, wherein pressurising the container
includes pressurising the volume of the container between the
inside of the container and the outside of the bag to between 1 to
3 bar, preferably between 1.5 to 2.5 bar, by undercup gassing.
12. The method of claim 1, the valve cup including an inverted
U-shaped receiving portion and the container including a lip
portion, wherein prior to welding the valve cup to the container,
the method further includes snap fitting the inverted U-shaped
receiving portion to the lip portion.
13. The method of claim 1, further comprising, before inserting the
bag into the container, folding the bag so as to decrease the
footprint of the bag to less than the diameter of the opening of
the container.
14. The method of claim 13, wherein folding includes twisting the
bag around a central axis of the valve or folding the bag into a
concertina pattern.
Description
[0001] The invention relates to a method for assembling a
dispensing system for dispensing a fluid medium stored under
pressure, the dispensing system exhibiting an improvement in
sealing performance and attachment between a valve cup and a
container.
BACKGROUND
[0002] Systems for dispensing a fluid medium stored under pressure
are generally well-known. Many systems dispense aerosols, such as
deodorant or paint, generally as a fine spray. However, any fluid
medium may be stored and dispensed, e.g., shampoo, etc.
[0003] Typical systems include a container, a valve, and a valve
cup, wherein the valve cup supports the valve usually at a central
part thereof and also closes off an opening of the container. The
inner volume of the container is usually pressurised and maintained
in such a state by the valve and the seals between the valve cup
and valve, and valve cup and container opening. When the valve is
actuated, the pressure difference between the inner volume of the
container and the outside environment causes the fluid medium to be
expelled from the container. Some systems employ a two-stage
container having an inner and outer container, one of which
contains the propellant gas, whereas others may employ a single
container with the fluid medium also acting as the propellant.
[0004] Traditionally, the containers are made from a metal, usually
aluminium. Recently, there has been an increasing trend to use
plastics, namely polyethylene terephthalate (PET), as the
containers for these dispensing systems for various advantages such
as cost and ease of manufacturing, among others. The systems should
be stable and be able to withstand the internal pressures of the
container while also providing an adequate seal.
[0005] Conventional systems employing PET containers also typically
use a metal, e.g., aluminium, for the valve cups which ensures a
suitable sealing engagement between the valve cup and valve. The
valve cup may be clinched to a lip of the opening of the container.
While the attachment between the valve cup and container is often
sufficient at most normal operating temperatures, higher
temperatures can cause the PET container to deform to a large
degree such that the connection between the aluminium valve cup and
container opening is no longer fluid tight. This is highly
disadvantageous as the propellant gas and/or the fluid medium can
escape from the container.
[0006] DE 37 37 265 A1 proposes a solution to this problem by
additionally forming the valve cup from a plastic, such as PET. In
this case, the valve cup can be welded, e.g., friction welded, to
the container because the valve cup and container are made of the
same or similar materials. At high temperatures, the weld is
sufficient to maintain the seal between the valve cup and the
container.
[0007] European safety requirements specify that aerosol systems
should not be exposed to temperatures above 50.degree. C. However,
in practice, such dispensing systems may be subject to much higher
temperatures. In the case of DE 37 37 265 A1, the disclosed device
does not provide sufficient sealing performance at temperatures
exceeding 50.degree. C. because the plastic valve cup may also
deform at these temperatures to the extent that the seal between
the valve cup and valve is lost.
[0008] A method for assembling a dispensing system for dispensing a
fluid medium and exhibiting sufficient sealing performance at
temperatures greater than 50.degree. C. is therefore required.
Herein, temperatures greater than 50.degree. C. should be
understood as reasonable temperatures that the dispensing system
might be exposed to, e.g., up to 100.degree. C.
SUMMARY
[0009] The problem is solved by a method for assembling a
dispensing system for dispensing a fluid medium stored under
pressure, the method including: [0010] providing a valve cup
including a valve and a bag, the valve configured to attach to an
opening of the bag, wherein the valve cup is either formed from a
first plastic or includes a lining formed from the first plastic;
[0011] inserting the valve into the opening of the bag and fluidly
sealing the bag to the valve; [0012] providing a container, the
container including an opening and suitable for storing a fluid
medium under pressure and formed, at least in part, from a second
plastic; [0013] inserting the bag into the container and
positioning the valve cup at the opening of the container; [0014]
pressurising the internal volume of the container; and [0015]
welding the valve cup to the container to thereby provide a seal
between the valve cup and the opening of the container.
[0016] In the above method, a bag is attached to a valve which
forms part of a valve cup. The valve cup and bag are subsequently
inserted in the container and positioned adjacent to the opening of
the container. In this state, the inner volume of the container may
be pressurised using a propellant gas, preferably by undercup
gassing. That is, the volume between the bag and container may be
pressurised. Assembling the dispensing system in this way allows
for the pressurised container to be attached to the valve cup in a
state ready to receive a fluid medium. The pressures may typically
be lower than as used in conventional containers.
[0017] Because the valve cup and the container are formed from
plastic, plastic welding can be used to join the two, thereby
providing a seal between the valve cup and the container. This seal
is particularly advantageous when deformation of the valve cup
and/or container occurs due to exposure to temperatures greater
than 50.degree. C. because the weld, and thus seal, is
maintained.
[0018] In another embodiment of the method above, the valve cup is
formed from the first plastic material, and the first plastic
material is a semi-crystalline polyester. The valve cup is a
component that supports the valve and is placed so as to cover the
opening of a container suitable for containing a fluid medium to be
dispensed. Semi-crystalline polyesters have a greater degree of
crystallinity compared to more amorphous polyesters. As a result,
semi-crystalline polyesters typically do not deform when exposed to
temperatures greater than 50.degree. C., at least as compared with
amorphous polyesters. In this way, structural rigidity of the valve
cup can be improved at higher temperatures meaning that the seal
between the valve held by the valve cup and the valve cup is
maintained.
[0019] A further embodiment of any of the methods above includes
the first plastic material having a degree of crystallinity greater
than 35%, preferably greater than 38%, when measured using
differential scanning calorimetry.
[0020] The degree of crystallinity is one property that provides
the plastic material with its rigidity at higher temperatures.
Typically, plastics may have some percentage of amorphous regions
and some percentage of crystallised regions. When exposed to high
temperatures, the amorphous regions undergo a transition from a
hard and brittle state to a more rubbery and soft state. Thus, it
can be considered that the amorphous regions lead to deformation of
the plastic at greater temperatures. Providing a material with a
higher degree of crystallinity may reduce the degree of deformation
of the plastic material at higher temperatures.
[0021] As a further note, the degree of crystallinity is generally
measured with respect to a certain method--here it is given as
differential scanning calorimetry (DSC). Generally, various methods
may give slightly different results because the degree of
crystallinity is essentially an average value. When using other
methods, an appropriate scaling should be taken into consideration
with respect to the value obtained by DSC.
[0022] In a further embodiment of any of the methods above, the
first plastic material is selected from the group consisting of:
crystallised PET, PBT, PEN, PEN/PET copolymers, or a blend of any
of the foregoing; and the second plastic material is a polyester,
preferably PET.
[0023] Crystallised PET (CPET), PBT, PEN, and PEN/PET copolymers
are or can be semi-crystalline polyesters. These materials are
particularly advantageous for their other properties in packaging
and not just the rigidity at elevated temperatures. However, any
polyester that can be semi-crystalline and does not deform to a
suitable degree at large temperatures may also be used as the
semi-crystalline material. Moreover, any blend of CPET, PBT, PEN,
and PEN/PET may be used as the first plastic material. In a
preferred embodiment, PBT is used as the first plastic
material.
[0024] Forming the container from a second plastic, such as PET,
can be highly beneficial. In this way, the container can retain the
advantages of PET as used in packaging, while also being able to be
coupled/welded to the valve cup formed of the first plastic. This
means that the seal between the valve cup and container can be
maintained, even if the container deforms.
[0025] In one embodiment of any of the methods above, the container
is entirely formed from the second plastic material. Forming the
container in this way means that the container retains the
beneficial properties of the second plastic. Polyesters, and in
particular PET, have many advantageous qualities in packaging
applications. They can be easy to manipulate and thus forming valve
cups and containers may be relatively easier and quicker. In some
cases, the polyesters may also be relatively cheap. Some polyesters
can also be recycled thus reducing the overall overhead cost.
Finally, some polyesters can also be sterilised which is
particularly advantageous for medical applications.
[0026] In another, alternative embodiment of the methods above, the
second plastic material is a semi-crystalline polyester.
[0027] In an alternative to the methods above, at least a part of
the container may be formed from the semi-crystalline material.
Preferably, this part is adjacent or in contact with the opening of
the container. This part may be a lip portion, a neck portion,
and/or the entire container. In this way, when the container
experiences elevated temperatures, the part adjacent or in contact
with the opening does not deform. In other words, at elevated
temperatures, the opening maintains its shape. In this way, any
seal with the valve cup can be maintained.
[0028] A further embodiment of the methods above provides the
container made from the second plastic material has a degree of
crystallinity greater than 35%, preferably greater than 38%, when
measured using differential scanning calorimetry.
[0029] Another embodiment of the methods above has the second
plastic material selected from the group consisting of:
crystallised PET, PBT, PEN, PEN/PET copolymers, or a blend of any
of the foregoing; and the first plastic material is a polyester,
preferably PET. Preferably, the second plastic material is PBT.
[0030] As above, reliable sealing may be achieved by ensuring that
the container is suitably sealed to the valve cup. Plastic valve
cups may be advantageous for various reasons such as cost and ease
of manufacturing. However, some plastic valve cups may be prone to
deformation at higher temperatures. Using a plastic valve cup
permits welding to the plastic container. Therefore, even if the
valve cup deforms, the container is fixed to the valve cup in such
a way that the seal therebetween is not broken. In other words, the
seal between the valve cup and container is maintained.
[0031] In some configurations, the rigid part of the container may
provide a sufficient rigid basis for any deformation of the valve
cup to be directed radially towards the valve supported by the
valve cup. In other words, the radial forces acting against the
rigid part of the container may cause a compressive force on a part
of the valve at the centre of the valve cup. This means that the
valve may be reliably held and sealed by the valve cup even if the
valve cup is formed of a deformable plastic.
[0032] In an alternative embodiment of the methods above, the valve
cup is formed from a metal or rigid material, and the valve cup
includes the polyester lining provided at at least a portion of the
valve cup that faces the container when assembled, wherein the
polyester lining is either held by the valve cup or is coated onto
the valve cup.
[0033] In an alternative valve cup, the valve cup may be formed of
two materials; a metal or rigid material body, and a polyester
lining. The metal or rigid material may be formed from any suitable
material that does not deform or warp at temperatures greater than
50.degree. C. That is, the rigidity of the valve cup is provided by
the metal or rigid material, which thereby ensures that the valve
is reliably held and sealed by the valve cup. The polyester lining
preferably covers at least a part of the metal or rigid material
valve cup. Preferably, this part faces the container when the valve
cup is fixed to the container. In this way, the valve cup may be
welded to a plastic container, thus enabling a seal between the
valve cup and the container.
[0034] The polyester lining is coated or held by the valve cup and
may be fixed by adhesive to the valve cup. The polyester lining may
be coated directly onto a surface of the valve cup, thus providing
a chemical bond between the metal or rigid material and the
polyester lining. This may be advantageous should the polyester
lining experience distortion when heated. Alternatively, the
polyester lining may be held by a specific configuration of the
valve cup, e.g., the valve cup may be shaped so as to be able to
crimp or clinch the polyester lining. This provides a mechanical
configuration which may be advantageous when coating is not
possible because of the materials chosen, or when the chemical
bonds do not sufficiently withstand deformation of the polyester
lining. The polyester lining may be provided on an underside of the
valve cup. The polyester lining may also be formed from any of the
semi-crystalline polyesters.
[0035] In a further embodiment of the method above, welding the
valve cup to the container includes welding the valve cup to the
container by any one of: friction welding, ultrasonic welding, and
laser welding.
[0036] These welding techniques are particularly advantageous as
they can be used to weld plastic to plastic, and do not cause any
propellant gas to adversely react, e.g., these techniques do not
provide a source of ignition.
[0037] Another embodiment of any of the methods involves
pressurising the volume of the container between the inside of the
container and the outside of the bag to between 1 to 3 bar,
preferably between 1.5 to 2.5 bar, by undercup gassing.
[0038] Although the pressure of 1 to 3 bar is not particularly
high, the pressurisation is performed without any fluid medium to
be dispensed disposed in the bag. In this way, when the dispensing
system is welded and sealed, any addition of the fluid medium to
the dispensing system via the valve thereof increases the pressure
within the container. This may then provide the necessary pressure
for dispensing the fluid medium. Performing the pressurisation in
this way means that the welding process is substantially easier
because the pressures involved are lower.
[0039] A further embodiment of any of the methods above involves
the valve cup including an inverted U-shaped receiving portion and
the container including a lip portion, wherein prior to welding the
valve cup to the container, the method further includes snap
fitting the inverted U-shaped receiving portion to the lip
portion.
[0040] The inverted U-shaped receiving portion can be provided on
an outer surface or diameter of the valve cup and is preferably
shaped and sized to receive a lip portion of the container. In this
manner, the valve cup can be reliably positioned with respect to
the container and can be suitably attached via, for example,
welding. The inverted U-shaped receiving portion may be provided
with at least one protrusion to aid in fixing, at least
temporarily, the valve cup to the container to thereby facilitate
the welding without concern of the valve cup being displaced.
[0041] Another embodiment of the method above further comprises,
before inserting the bag into the container, folding the bag so as
to decrease the footprint of the bag to less than the diameter of
the opening of the container. Preferably, the folding includes
twisting the bag around a central axis of the valve or folding the
bag into a concertina pattern.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 shows an assembled dispensing system that may be
assembled in accordance with the present invention;
[0043] FIG. 2a shows a cross-section of the valve cup of FIG.
1;
[0044] FIG. 2b shows a top-down view of valve cup in FIG. 2a;
[0045] FIG. 3 shows an exploded view of the valve cup and container
of FIG. 1;
[0046] FIG. 4 shows an exemplary valve cup; and
[0047] FIG. 5 shows a method for assembling a dispensing system in
accordance with the present invention.
DETAILED DESCRIPTION
First Example
[0048] FIG. 1 shows a dispensing system 1. The dispensing system 1
includes a valve cup 10 according to a first example that may be
used with the method according to the invention, a container 30,
and a valve 50. Typically, the inner region of the container 30 is
pressurised to a pressure greater than atmospheric pressure. When a
fluid medium is stored within the container, this pressure may be 7
bar, although the pressure is not limited to this and may take any
desired value limited only by regional or governmental
restrictions. The valve 50 is generally held in a fixed position by
the valve cup 10 such that, when a force is applied to the valve 50
from a user, the valve 50 can be actuated to an open position. In
this position, the pressure difference causes the fluid medium to
be distributed from the container 30 via the valve 50.
[0049] The valve 50 is shown in detail in FIG. 1, but it should be
appreciated that any suitable known valve can be substituted for
valve 50. In FIG. 1, the valve 50 may include a main body 52 which
is preferably cylindrical and includes a hollow inner portion. A
plunger 53 may also be provided and communicates with the hollow
inner portion of the main body 52. In some examples, the plunger 53
may be disposed totally within the main body 52, but preferably has
a dispensing tip 54 protruding away from the main body 52.
[0050] The dispensing tip 54 may have any cross-sectional shape but
is preferably cylindrical. The dispensing tip 54 may also include
an upper channel 55 that defines a hollow inner portion of the
dispensing tip 54. A through hole 56 may be provided at a lower
portion of the dispensing tip 54. In FIG. 1, the through hole 56
extends perpendicularly to the axis of the upper channel 55, but
the through hole 56 is not limited to this configuration. The main
body 52 of the valve 50 may also include a lower channel 57 that
extends from a lower part of the main body 52. In one
configuration, as seen in FIG. 1, the upper and lower channels 55,
57, and the plunger 53 and main body 52 share the same common
central axis.
[0051] The plunger 53 may be provided so as to slide in the
direction of the common central axis. The plunger 53 may be biased
to a closed position by a spring (not shown) disposed in the hollow
portion of the main body 52 and communicating with receiving parts,
such as perpendicular flanges, of the plunger 53. FIG. 1 shows a
possible closed position whereby the lower channel 57 is prevented
from fluidly communicating with the upper channel 55 and through
hole 56 by a seal member 60, described in more detail below. To
actuate the valve 50, a user may apply a downward force in the
axial direction of the main body 52, thereby causing the plunger 53
to traverse downwards (with respect to FIG. 1) such that the
through hole 56 communicates with the hollow part of the main body
52. In this way, the upper and lower channels 55, 57 may be in
fluid communication in this open position. Based on the pressure
difference, the fluid medium can be evacuated from the container 30
through the lower channel 57, the hollow portion of the main body
52, the through hole 56, and finally the upper channel 55. A cap or
other directional device may be provided to communicate with the
dispensing tip 54 to direct the flow of the fluid medium when
exiting the upper channel 55 as is known in the art.
[0052] Optionally, a bag 100 (see FIG. 5) may be attached to the
valve 50. The valve 50 may have recesses 58 or any other means to
allow for attachment of the bag 100 to the valve 50. Preferably,
the bag 100 has an opening that fits around the lower channel 57 of
the valve 50. In this way, the inner volume of the bag 100 may be
in fluid communication with the lower channel 57 and hence also the
upper channel 55 when the valve 50 is actuated. In this preferred
configuration, the fluid medium may be housed in the bag 100 and
the inner volume of the container 30 between the walls of the
container 30 and the bag 100 may be pressurised with propellant
gas. In the alternative, the fluid medium may also act as the
propellant gas in the absence of the bag 100.
[0053] The valve 50 is supported by the valve cup 10. In the
example of FIG. 1, the valve 50 is centrally mounted in the valve
cup 10; that is, the valve cup 10 and valve 50 share the same
central axis. The valve cup 10 may have a central opening 11 for
such a purpose, as seen in FIG. 2a. However, it should be
appreciated that any mounting configuration of the valve 50 can be
employed.
[0054] FIGS. 2a and 2b further highlight the exemplary mounting
configuration for mounting the valve 50 to the valve cup 10. The
central opening 11 may be defined by an inclined portion 13 of the
valve cup 10. The inclined portion 13 may define an outer diameter
d1 at its thickest point and slope towards the central opening 11,
the central opening 11 having a diameter smaller than d1. The
diameter d1 is preferably larger that the diameter of the main body
52 of the valve 50. In one example configuration, the diameter d1
may be 14 mm, but the diameter d1 is not limited to this value. It
should also be appreciated that the inclined portions 13 do not
have to be inclined, but should at least project towards the
central opening 11. The inclined portion 13 may also have a number
of first inner projections 12 disposed at the sides facing central
opening 11. While FIG. 2b shows eight first inner projections 12,
the present invention is not limited to this number. These first
inner projections 12 may communicate with the outer diameter of the
dispensing tip 54 of the valve 50 in order to firmly support the
dispensing tip 54 as seen in FIG. 1.
[0055] The valve main body 52 may be supported by second inner
projections 14 that, in FIG. 2a, are disposed below the inclined
portions 13. In this way, the valve 50 may be threaded through the
valve cup 10 from a lower side thereof (i.e., starting from the
direction where the container 30 is positioned in FIG. 1) until the
top of the main body 52 abuts either the lower side of the inclined
portions 13 or the seal member 60 positioned at the lower side of
the inclined portions 13. Projections on the top of the main body
52 as seen in FIG. 1 may also be provided so as to accommodate the
seal member 60. A groove 59 in the top part of the valve main body
52 may also be provided to aid in aligning the seal member 60,
allowing the seal member 60 to flex, and/or equalising the
pressure.
[0056] The seal member 60 is preferably sized so as to surround the
outer diameter of the dispensing tip 54 and cover the through hole
56 in the closed position, as seen in FIG. 1. When the plunger 53
is pressed downwards by the user, the seal member 60 may be
permitted to flex by virtue of the groove 59, although this is not
essential.
[0057] When assembling the valve 50 and valve cup 10, the seal
member 60 may be inserted into the lower region of the valve cup 10
defined by the second inner projections 14, or the seal member 60
may be positioned on top of the valve main body 52. In any case,
when the valve 50 is threaded into the valve cup 10 such that the
dispensing tip 54 passes through the central opening 11, the second
inner projections 14 may hold the valve main body 52 in place. In
some examples, the second inner projections 14 may include raised
portions 15 that snap fit into corresponding receiving portions
provided in the valve main body 52. FIG. 1 exemplifies this
configuration in more detail. This configuration enables the valve
50 to be rigidly held and sealed by the valve cup 10.
[0058] The structure of the valve cup 10 is not particularly
limited. FIGS. 1, 2a, and 2b show one exemplary configuration,
although the specific construction is not limited to that shown.
The valve cup 10 may include inverted U-shaped receiving portions
16 that are adapted to receive a lip portion 38 of the container
30. The outer side of the inverted U-shaped receiving portions 16
may define the outer dimension or diameter d2 of the valve cup 10.
Preferably, the diameter d2 is greater than outer diameter of an
opening 32 of the container 30. In one example configuration, the
diameter d2 may be 34.1 mm, but the diameter d2 is not limited to
this value.
[0059] The inverted U-shaped receiving portions 16 may define a
space wherein the inner surfaces of the inverted U-shaped receiving
portions 16 may contact the lip portion 38 of the container 30 when
the valve cup 10 is attached to the container 30. The innermost
surface of the inner surfaces may define a diameter d3 of the valve
cup 10 which may be equal to or less than the inner diameter of the
opening 32. In one example configuration, the diameter d3 may be
24.8 mm, but the diameter d3 is not limited to this value. In some
configurations, the outermost surface of the inner surfaces may be
provided with a projection 17 extending towards the innermost
surface. As seen in FIG. 1, the projection 17 may mate with a lower
part of the lip portion 38. Preferably, the projection 17
facilitates a snap-fit engagement of the valve cup 10 with the
container 30 which may improve the ease of the welding process
between the valve cup 10 and container 30 by ensuring correct
alignment.
[0060] The inverted U-shaped receiving portions 16 may have a
height h1 than is greater than the height of the lip portion 38
such that the lip portion 38 is completely contained within the
inverted U-shaped receiving portions 16. This configuration is seen
in FIG. 1. In one example configuration, the height h1 may be 6.7
mm, but the height h1 is not limited to this value. The valve cup
10 may also have a section that connects the outer part of the
inclined portions 13 to the inner part of the inverted U-shaped
receiving portions 16. This section may define a second height h2
than is greater than the height h1 such that the section is
positioned below the lip portion 38. In one example configuration,
the height h2 may be 9.25 mm, but the height h2 is not limited to
this value.
[0061] The section may also be provided with a number of enforcing
members or portions 18 that extend from the inverted U-shaped
receiving portions 16 to the outer side of the inverted portions
13. This may aid in increasing the structural rigidity of the valve
cup 10 while also reducing production costs and material
consumption. FIG. 2b shows eight enforcing portions 18 but the
number is not limited to this and more or less enforcing portions
18 can be used depending on the desired structural requirements.
The enforcing portions 18 can be made of the same material as the
valve cup 10 or a different material. The enforcing portions 18 may
be integrally formed with the valve cup 10 or formed as separate
components.
[0062] As mentioned above, the valve cup 10 is configured to be
attached to the container 30. In FIG. 3, the container 30 comprises
an opening 32 that is circular; however, any shaped opening 32 may
be used. The container 30 may comprise a main body 34 that is
connected to the opening 32. In some preferred configurations, the
container 30 may include a neck portion 36 which connects the
opening 32 to the main body 34. The lip portion 38 may be provided
as part of the neck portion 36 or as a separate component. The
general dimensions of the container 30 are not limited in any
particular manner, aside from the relationships with respect to the
dimensions of the valve cup 10 as mentioned above.
[0063] In accordance with the present invention, the valve cup 10
may be formed from a plastic material that is a semi-crystalline
polyester. In this manner, the structural rigidity of the valve cup
10 can be ensured beyond the recommended 50.degree. C. owing to the
higher degree of crystallinity. In some cases, the degree of
crystallinity may be greater than 35%, and preferably greater than
38% when measured using differential scanning calorimetry (DSC).
DSC is a well-established method for measuring thermal properties
of materials and is not explained further herein.
[0064] One material that can be used for the valve cup 10 of the
present invention is crystallised PET (CPET). PET can either be
amorphous or semi-crystalline, depending on how it is processed.
Typically, PET can be injection moulded using a suitable mould
(e.g., a valve cup). When a standard cycle time is used, the
resulting PET product is completely amorphous. A semi-crystalline
plastic is one that displays crystalline structures but also
amorphous regions. When heated, the amorphous regions can
transition from a hard and brittle state to a rubbery, soft, and
elastic state; the temperature at which this occurs is known as the
glass transition temperature. In a semi-crystalline plastic, the
rigidity of the plastic is proportional to the degree of
crystallinity, which essentially defines the percentage of the
plastic that exhibits crystalline structures. Because the
crystalline structures do not undergo the transition from hard to
rubbery states, the crystalline structures keep their shape and
thus can maintain the rigidity of the semi-crystalline plastic even
when the amorphous regions do make the transition at the glass
transition temperature.
[0065] The approximate degree of crystallinity of PET ranges from
30% to 40%, although other percentages may be possible. CPET may be
formed by heating virgin PET and allowing the heated PET to cool
slowly, more slowly than prescribed by a standard cycle used in
injection moulding, thus forming crystalline structures. Thus, CPET
has a high degree of crystallinity. In contrast, amorphous PET
(APET) is cooled much more quickly preventing the crystalline
structures from forming.
[0066] CPET may also have nucleating agents added thereto in order
to enhance the formation of crystalline structures in the material.
Alternatively, other additives may be introduced to PET in order to
increase the stiffness and/or durability, e.g., glass particles or
fibres.
[0067] Typically, PET films and bottles have a limited degree of
crystallinity and usually have small crystallites leading to a
clear and transparent material. This is perhaps the most common
form of PET. CPET requires more careful control when forming and
thus can be much more costly to produce.
[0068] CPET is much less subject to deformation under stress,
especially at larger temperatures, than amorphous PET (APET). This
is primarily because of the rigidity of the crystalline structures
therein. Because semi-crystalline polyesters include both
crystalline and amorphous regions, they can be characterised by a
glass transition temperature. For PET, the glass transition
temperature is between 67.degree. C. for amorphous PET to
81.degree. C. for semi-crystalline PET. Therefore, in the case of
PET, a higher glass transition temperature correlates with a larger
degree of crystallinity, and thus PET having a higher glass
transition temperature is desired for use as the valve cup 10,
preferably over 74.degree. C.
[0069] In a preferential embodiment, polybutylene terephthalate
(PBT) is used as the plastic material of the valve cup 10. PBT is
always semi-crystalline in normal commercial settings. Typically,
the degree of crystallinity is always greater than 30%, and is
usually in the range of 40% to 50%. Although the glass transition
temperature is approximately 66.degree. C. for PBT, PBT is
generally more rigid that amorphous PET owing to the higher degree
of crystallinity. This makes PBT an excellent choice of material
for use as the valve cup 10.
[0070] Yet another material that is suitable is polyethylene
napthalate (PEN). PEN is very stable, particularly at higher
temperatures. PEN can also form a semi-crystalline structure and
has a glass transition temperature of approximately 125.degree. C.
Compared to PET, PEN has higher oxygen and water vapour barrier,
tensile strength and flexural modulus. In addition, moulding and
blowing cycles for PEN are much shorter than for PET leading to
increased productivity. However, the cost of PEN is, at present,
much higher than PET.
[0071] It should also be appreciated than many other polyesters may
be used provided that they display appropriate semi-crystalline
properties. Blends of polyesters may also be used. In one example,
a PEN/PET copolymer may be used, wherein the percentage of PEN is
relatively low in comparison to the percentage of PET, e.g.,
between 10-20% PEN for reasons of cost. Other copolymers may be
used such as PET/PBT copolymers, or even PET/PBT/PEN copolymers.
However, any of PET, PBT, or PEN may also be blended with other
polyesters and/or other additives, such as nucleating agents, to
form semi-crystalline structures.
[0072] Moreover, when the valve cup 10 is formed from a
semi-crystalline polyester, the valve cup 10 can be welded to the
container 30 when the container is formed of a second plastic
material. The welding can be performed using any suitable technique
to weld two plastics together, but is preferably one of friction
welding, ultrasonic welding, or laser welding. In this case, the
container 30 may be formed of PET with any appropriate degree of
crystallinity and subsequently welded to the valve cup 10. This
ensures that the valve cup 10 (e.g., the inverted U-shaped
receiving portion 16) does not separate from the container 30
(e.g., the lip portion 38) even when deformation of the container
30 at high temperatures occurs.
[0073] In accordance with the first valve cup 10 to be used in the
method of the invention, using a semi-crystalline polyester as the
material for the valve cup 10 ensures that the valve 50 is suitable
held by the valve cup 10 at temperatures over 50.degree. C. because
deformation or distortion of the valve cup 10 does not occur. In
addition, using a semi-crystalline polyester as the material for
the valve cup 10 means that a plastic container 30 can be welded to
the valve cup 10 thus ensuring that the seal between the container
30 and valve cup 10 is maintained even if deformation of the
container 30 occurs. Thus, the advantageous properties of PET when
used as the container 30 can be retained without compromising
sealing performance at higher temperatures.
[0074] It should be appreciated, however, that the material of the
container 30 is not limited to PET but may be any suitable
polyester and may also be formed of any of the semi-crystalline
polyesters above.
[0075] As discussed above, the rigidity of the valve cup 10 can
also be improved by using the enforcing members 18. The enforcing
members 18 may be formed of the same semi-crystalline polyester or
may be formed of a different material, e.g., metal.
[0076] It should be appreciated that various modifications to the
specific structure of the valve cup 10, container 30, and valve 50
may be made while still conforming to the principles of the first
example of the invention.
Second Example
[0077] As a second example of a component to be used with the
method of the invention, a part of the container 30 may be formed
from any of the semi-crystalline polyesters used for the valve cup
10 of the first example. Specifically, a part adjacent or in
contact with the opening 32 of the container 30 may preferably be
formed from the semi-crystalline polyester. In contrast, the valve
cup 10 may be formed from any polyester, such as PET.
[0078] In the second example, the opening 32 of the container 30
maintains its rigidity at temperatures exceeding 50.degree. C. by
virtue of being formed from the semi-crystalline polyester. The
valve cup 10 may maintain the seal with respect to the valve 50 due
to the compressive forces acting radially inward from the opening
32 of the container 30 if the valve cup 10 begins to deform at
higher temperatures.
[0079] Alternatively, the valve cup 10 may be structured in such a
manner as to channel any deformation to areas away from the valve
50, i.e., away from inclined portion 13. For example, with
reference to FIG. 2a, the difference in heights h1 and h2 may aid
in channeling any deformation to be concentrated in the sections
connecting the inverted U-shaped receiving portion 16 and the
inclined portion 13. Other structural configurations may also be
considered. In some cases, the enforcing members 18 may be
configured to prevent any deformation of the valve cup 10 at
locations surrounding the valve 50.
[0080] In the second example, the container 30 is preferably formed
from the semi-crystalline polyester only at a portion adjacent or
in contact with the opening 32. This may include only the lip
portion 38. Alternatively, the entire neck portion 36 and lip
portion 38 may be made from the semi-crystalline polyester. In
other configurations, the entire container 30 may be formed from
the semi-crystalline polyester, although this may increase the
costs and/or difficulty of the manufacturing processes associated
with forming the container 30.
[0081] As with the first example, using a semi-crystalline
polyester as the material for at least a part of the container 30
ensures that the valve cup 10 is suitably held by the container 30
at temperatures over 50.degree. C. because deformation or
distortion of the opening 32 of container 30 does not occur. This
can limit or appropriately deflect any deformation of the valve cup
10 meaning that the valve 50 is stably held. In addition, using a
semi-crystalline polyester as the material for a part proximate to
the opening 32 of the container 30 means that a polyester valve cup
10 can be welded to the container 30 thus ensuring that the seal
between the container 30 and valve cup 10 is maintained even if
deformation of the valve cup 10 occurs. The advantageous properties
of using PET when used as the valve cup 10 and potentially as part
of the container 30 can be retained without compromising sealing
performance at higher temperatures.
[0082] It should be appreciated, however, that the material of the
valve cup 10 is not limited to PET but may be any suitable
polyester and may also be formed of any of the semi-crystalline
polyesters above.
Third Example
[0083] As a third example of a component to be used in the assembly
method of the present invention, the primary material of the valve
cup 10 may be a metal or other rigid material. Preferably, the
primary material is aluminium. The structure of the valve cup 10
may be the same as in the first example.
[0084] FIG. 4 shows an example of the valve cup 10 in accordance
with the third example. In FIG. 4, a polyester lining 70 may be
provided on a surface of the valve cup 10, preferably at a portion
that contacts the container 30. The polyester lining 70 may be
formed only in a region that contacts the container 30, e.g., on
the inner surfaces of the inverted U-shaped receiving portion 16,
or may be formed entirely on the lower surface of the valve cup 10.
Additionally, the polyester lining 70 may be coated on the valve
cup 10, or may be a separate component that is subsequently
attached thereto via adhesive and/or held by the valve cup 10. In
this regard, the valve cup 10 may be configured to clamp or hold a
part of the polyester lining 70.
[0085] The polyester lining 70 may be formed from any polyester,
but is preferably formed from PET. When the valve cup 10 is formed
of a metal, i.e., aluminium, or other rigid material, the
structural rigidity of the valve cup 10 at temperatures greater
than 50.degree. C. is ensured by the structural rigidity of the
metal or rigid material. In other words, the metal or rigid
material does not deform at temperatures greater than 50.degree. C.
This means that the valve cup 10 may reliably hold and seal the
valve 50.
[0086] Providing the polyester lining 70 on a part of the valve cup
10 means that the polyester lining 70 can be welded using any of
the aforementioned techniques to a polyester based container 30,
e.g., the container 30 of the first example. In this way, the valve
cup 10 can be reliably attached to the container 30 such that any
deformation of the container 30 at temperatures greater than
50.degree. C. does not cause the valve cup 10 and container 30 to
separate, and thus the seal therebetween is maintained.
[0087] The advantageous effects described in both the first and
second examples can therefore be realised by the third example;
namely, that the seal between the valve 50 and valve cup 10 and the
seal between the valve cup 10 and container 30 can be maintained at
temperatures greater than 50.degree. C.
[0088] As seen in FIG. 4, the polyester lining 70 may also be
provided with projections 77 similar to the projections 17 of the
first example. The projections 77 may be formed additionally as
part of the polyester lining 70, i.e., varying thickness of the
polyester lining 70, or they may be formed as a natural consequence
of following the projections 17 when coating the valve cup 10.
[0089] The polyester lining 70 does not have to be formed from the
semi-crystalline polyesters as discussed in the first and second
examples. However, in some cases, to prevent deformation of the
polyester lining 70 that may lead to detachment from the valve cup
10, the polyester lining 70 may be formed from the semi-crystalline
polyesters.
[0090] Method for Assembling Dispensing System
[0091] In accordance with an embodiment of the present invention, a
method of assembling the dispensing system using valve cups 10 or
container 30 as described in any of the first through third
examples is now given.
[0092] FIG. 5 details a method of assembling the dispensing system
1 according to the present invention. Initially, the valve 50 is
coupled to the valve cup 10. An exemplary method for performing
this coupling has been described with respect to the first example,
and so will not be repeated here. Essentially any method or
coupling may be performed depending upon the exact structure of the
valve 50 and the valve cup 10.
[0093] A first step of the invention, as shown in FIG. 5(a),
involves coupling the bag 100 to the valve 50. More specifically,
an opening of the bag 100 is attached to a lower part of the valve
50, e.g., lower channel 57, such that the valve 50 can be in fluid
communication with the interior of the bag 100 when actuated. The
valve 50 may be provided with any means for facilitating this
coupling, such as the recesses 58 in FIG. 1. The bag 100 may be
secured by any suitable means such as adhesive, welding, or
clamping. The combination of bag 100 and valve 50 in a fixed
arrangement is generally referred to as a Bag On Valve (BOV). The
bag 100 is preferably liquid, gas, or fluid impermeable.
[0094] Once the bag 100 is securely attached to the valve 50, the
bag 100 may be folded to reduce the footprint thereof. As shown in
FIG. 5(b), the bag 100 may be folded in such a way that the
footprint is less than the diameter of the valve cup 10.
Preferably, the footprint is less than the diameter of the opening
32 of a container 30 to which the valve cup 10 is to be assembled
such that the BOV may be inserted into the opening 32. In an
exemplary method, the BOV is folded such that the footprint has a
diameter d4 less than 25 mm or 22 mm, although other diameters are
possible.
[0095] The folding may be performed in any manner so as to reduce
the footprint of the BOV and allow insertion into the container 30.
In one embodiment, the flat bag 100 is rolled around the axis of
the valve 50 and valve cup 10 such that the bag 100 is in a
spiraled configuration centred on the axis of the valve 50. In
another embodiment, the bag 100 may be folded in a concertina. In
both cases, the BOV is preferably provided with a suitable
footprint.
[0096] In contrast to known methods, the BOV may not be provided
with a containing sleeve or tape to retain the BOV in the folded
configuration. According to the present invention, the folded BOV
is inserted directly into the container 30, as is shown in FIG.
5(c). In this step, the BOV is slid through the opening 32 of the
container 30 while maintained in the folded state to improve the
ease of insertion.
[0097] Once partially inserted, the inner region of the container
30 may be filled with gas, preferably a propellant gas. Suitable
propellant gasses are known in the art and are not discussed
further herein. The method used is preferably undercup gassing,
which essentially means that the gas is passed under the valve cup
10 and into the region between the bag 100 and the inner volume of
the container 30. In the present invention, the inner volume of the
container 30 may be pressurised to a pressure between 1 to 3 bar,
preferably 1.5 to 2.5 bar.
[0098] As seen in FIG. 5(d), once the gassing is complete, the BOV
is inserted into the container 30 such that valve cup 10 contacts
the opening 32 of the container 30. In a preferred configuration,
the valve cup 10 is provided with the inverter U-shaped receiving
portion 16 and the container 30 is provided with the lip portion
38. Thus, the BOV may be inserted into the container 30 until the
lip portion 38 of the container 30 abuts the inverted U-shaped
receiving portion 16.
[0099] In a more preferably configuration, the inverted U-shaped
receiving portion 16 comprises the projections 17, 77 which are
adapted to engage in a snap-fit manner with the underside of the
lip portion 38. In this way, when the valve cup 10 is pressed onto
the lip portion of the container 30, the U-shaped receiving portion
16 may deform slightly to allow the projections 17, 77 to pass over
the lip portion 38 and subsequently return to their resting state
once the projections 17, 77 have passed over the lip portion 38.
Securing the valve cup 10 in this way aids in ensuring that the
welding process is performed with improved accuracy as the valve
cup 10 can be reliably aligned with the container 30.
[0100] As seen in FIG. 5(e), a welding head 110 may be positioned
over the valve cup 10 in order to weld the valve cup 10 to the
container 30. As described in the first through third examples, the
valve cup 10 and container 30 may be formed, at least in part, from
plastics. This means that welding or plastic welding, such as
friction welding, ultrasonic welding, or laser welding, can be
performed so as to weld the valve cup 10 to the container 30. Any
of the welding techniques can be used and these techniques are
generally known in the art and so are not described in any further
detail herein.
[0101] Once the welding is completed, the dispensing system 1 is
assembled. Further assembly steps may be possible, such as adding a
protection overcap 120 to cover the exposed part of the valve 50 as
in FIG. 5(f). The assembled dispensing systems 1 may then be
transported to various consumers to be filled with a variety of
different products. To fill the dispensing systems 1, the fluid
medium to be dispensed is passed through the valve 50 into the bag
100, i.e., via upper channel 55, through hole 56, and lower channel
57. The pressure in the container 30 increases as the bag 100 fills
with the fluid medium. Preferably, the pressure increases to around
6 to 8 bar, preferably 6.5 to 7.5 bar. This increase in pressure
aids in dispensing the fluid medium when the valve 50 is actuated
by a user.
[0102] It should be noted that some or all of the steps of the
method may be performed in a sealed environment. This may aid in
assembling the dispensing system 1 when the pressure is
increased.
[0103] According to this method, the dispensing systems are
assembled by welding the valve cup 10 to the container 30 after
experiencing undercup gassing. Conventional methods generally rely
on clinching the valve cup to the container, whereas the present
assembly method utilises the welding of a specially modified valve
cup 10 to a container 30. The welding may also be performed at
lower pressures and without the presence of the fluid medium to the
dispensed. This can ensure a more reliable weld and potentially
prevent any contamination of the fluid medium to be dispensed.
[0104] The present invention therefore provides a method for
assembling a dispensing system 1 for dispensing a fluid medium, the
dispensing system 1 including a valve cup 10 or container 30 that
is modified to be rigid at temperatures exceeding 50.degree. C.,
while also allowing for welding between the valve cup 10 and
container 30. Primarily, this can be achieved by using either a
semi-crystalline polyester with a high degree of crystallinity, or
by making use of a polyester layer on a metal or rigid material
valve cup.
* * * * *