U.S. patent application number 10/182607 was filed with the patent office on 2002-12-19 for metering valve for dispensers.
Invention is credited to Stanford, Anthony.
Application Number | 20020190085 10/182607 |
Document ID | / |
Family ID | 9887138 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020190085 |
Kind Code |
A1 |
Stanford, Anthony |
December 19, 2002 |
Metering valve for dispensers
Abstract
The invention relates to improvements in metering valves for use
in dispensing apparatus. There is provided a metering valve (10)
for assembly with a pressurised dispensing container (not shown).
The valve (10) comprises a valve stem (20) co-axially slidable
within a valve body (16, 17) defining a metering chamber. Inner and
outer seals (15, 18) are provided for scaling between the valve
body and the valve stem and a gasket (14) is located on the valve
body for sealing against a neck portion of a pressurised disposing
container. At least one of the inner seal, outer seal or gasket is
formed as a co-moulding with at least part of the valve body.
Inventors: |
Stanford, Anthony;
(Leicestershire, GB) |
Correspondence
Address: |
KENNEDY COVINGTON LOBDELL & HICKMAN, LLP
100 N TRYON STREET
BANK OF AMERICA CORPORATE CENTER
CHARLOTTE
NC
28202-4006
US
|
Family ID: |
9887138 |
Appl. No.: |
10/182607 |
Filed: |
August 1, 2002 |
PCT Filed: |
February 28, 2001 |
PCT NO: |
PCT/GB01/00869 |
Current U.S.
Class: |
222/402.1 |
Current CPC
Class: |
B65D 83/54 20130101 |
Class at
Publication: |
222/402.1 |
International
Class: |
B65D 083/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 7, 2000 |
GB |
0005481.7 |
Claims
1. A metering valve for assembly with a pressurised dispensing
container, the valve comprising a valve stem co-axially slidable
within a valve body defining a metering chamber, inner and outer
seals for sealing between the valve body and the valve stem, and a
gasket located on the valve body for sealing against a neck portion
of a pressurised dispensing container, wherein at least one of the
inner seal, outer seal or gasket is formed as a co-moulding with at
least a part of the valve body.
2. A metering valve as claimed in claim 1 wherein the valve body
comprises inner and outer members.
3. A metering valve as claimed in claim 2 wherein the inner seal is
formed as a co-moulding with the inner member.
4. A metering valve as claimed in claim 2 wherein the inner seal is
formed as a co-moulding with the outer member.
5. A metering valve as claimed in either claim 3 or claim 4 wherein
the outer seal is formed as a co-moulding with the outer
member.
6. A metering valve as claimed in any of claims 2 to 5 wherein the
gasket is formed as a co-moulding with the inner member.
7. A metering valve as claimed in any of claims 2, 3, 5 or 6
wherein the inner seal is formed as a co-moulding with the gasket
and at least a part of the valve body.
8. A metering valve as claimed in claim 7 wherein the inner seal,
gasket and inner member are formed as a co-moulding.
9. A metering valve as claimed in any of claims 2 to 8 wherein the
inner member is a made of a first material and the inner seal and
gasket are formed of a different material.
10. A metering valve as claimed in any of claims 2 to 9 wherein the
outer member is a made of a first material and the outer seal is
formed of a different material.
11. A metering valve as claimed in claim 9 or claim 10 wherein the
first material is selected from acetal, nylon and polyester.
12. A metering valve as claimed in any of claims 9 to 11 wherein
the different material is selected from polyurethane, thermoplastic
vulcanizates, polystyrene polyethylenebutylene block copolymers,
polystyrene polybutadiene block copolymers, thermoplastic
polyolefin, co polyether ester, polyether block amides and
polyethylene copolymers.
13. A co-moulding for use in a metering valve comprising at least a
part of a valve body, inner seal and gasket formed as a
co-moulding.
14. A co-moulding for use in a metering chamber comprising at least
a part of a valve body and a seal formed as a co-moulding.
15. A method of manufacturing a co-moulding for use in a metering
valve comprising the steps of forming a first mould shape,
injection moulding a first material to form a part of a valve body,
forming a second mould shape containing the part of the valve body,
and injection moulding a different material to form at least one
sealing element in intimate relationship with the part of the valve
body.
16. A method as claimed in claim 15 wherein the part of the valve
body is formed as an inner member of a valve body and the at least
one sealing element is formed as an inner seal.
17. A method as claimed in claim 15 wherein the part of the valve
body is formed as an inner member and the at least one sealing
element is formed as a unitary inner seal and gasket.
18. A method as claimed in claim 15 wherein the part of the valve
body is formed as an outer member and the at least one sealing
element is formed as an outer seal.
Description
[0001] The invention relates to improvements in metering valves for
use in dispensing apparatus.
[0002] Dispensing apparatus, for dispensing metered doses of
product, generally comprise a valve attached to a dispensing
container in which the product to be dispensed is stored. The valve
is held in position relative to the dispensing container by means
of a cap or ferrule which is crimped to an open neck of the
container.
[0003] In metered dose valves, a metering chamber is provided
sealed at respective inner and outer ends by inner and outer seals.
The outer seal prevents leakage of product between the metering
chamber and atmosphere when the apparatus is in a non-dispensing
position. The inner seal prevents leakage of product between the
container and the metering chamber when the dispensing apparatus is
in an operative, dispensing position. In addition in order to
provide an adequate seal to prevent loss of the stored product, an
elastomeric sealing gasket is provided between the cap or ferrule
and container.
[0004] Assembly of the inner and outer seals and the elastomeric
gasket with the remainder of the components of the metering valve
requires a number of assembly steps which can be time consuming and
difficult to achieve, in part due to the small size of the
components. In particular, the assembly of the inner seal and the
elastomeric gasket with the valve body of the metering valve
firstly requires inner and outer members of the valve body to be
assembled, sandwiching the inner seal between the inner and outer
members. Up until this point in the assembly process, the inner
seal is held in position relative to the valve body only by
frictional forces set up between the inner seal and the inner
member of the valve body. A problem found with this arrangement is
that during manipulation of the inner member in preparation for
assembly with the outer member the inner seal may potentially be
displaced from its correct position.
[0005] The elastomeric gasket is then push-fitted onto the valve
body.
[0006] The outer seal is assembled with the outer member and the
cap or ferrule is then placed over the valve stem to retain the
outer seal on the valve body. A problem found with this arrangement
is that during manipulation of the valve body in preparation for
assembly with the cap or ferrule the outer seal may potentially be
displaced from its correct position.
[0007] The metering valve is then attached to a dispensing
container by crimping the cap or ferrule over the open end of the
dispensing container such that the neck portion of the container
engages the elastomeric gasket. Up until this point in the assembly
process, the elastomeric gasket is retained on the valve body only
by frictional forces set up between the elastomeric gasket and the
inner member. A problem with this arrangement is that during
manipulation of the inner member during assembly with the outer
member, and during manipulation of the assembled valve body during
assembly with the dispensing container, the elastomeric gasket may
potentially be dislodged from its correct position on the valve
body.
[0008] According to the present invention there is provided a
metering valve for assembly with a pressurised dispensing
container, the valve comprising a valve stem co-axially slidable
within a valve body defining a metering chamber, inner and outer
seals for sealing between the valve body and the valve stem, and a
gasket located on the valve body for sealing against a neck portion
of a pressurised dispensing container, wherein at least one of the
inner seal, outer seal or gasket is formed as a co-moulding with at
least a part of the valve body.
[0009] There is also provided a co-moulding for use in a metering
valve comprising at least a part of a valve body, inner seal and
gasket formed as a unitary component.
[0010] There is also provided a co-moulding for use in a metering
chamber comprising at least a part of a valve body and a seal
formed as a unitary component.
[0011] The present invention also discloses a method of
manufacturing a co-moulding for use in a metering valve comprising
the steps of forming a first mould shape, injection moulding a
first material to form a part of a valve body, forming a second
mould shape containing the part of the valve body, and injection
moulding a different material to form at least one sealing element
in intimate relationship with the part of the valve body.
[0012] Embodiments of the present invention will now be described,
by way of example only, with reference to the accompanying drawings
in which:
[0013] FIG. 1 shows a cross-sectional side elevation of a metering
valve according to the present invention;
[0014] FIG. 2a shows a perspective view of a sectioned inner member
of a valve body of the metering valve of FIG. 1;
[0015] FIG. 2b shows a perspective view of the inner member of FIG.
2a from a different angle;
[0016] FIG. 3 shows a perspective view of a sealing gasket and
inner seal of the metering valve of FIG. 1;
[0017] FIG. 4a shows a plan view of the inner member of FIG. 2a
moulded with the sealing gasket and inner seal of FIG. 3;
[0018] FIG. 4b shows a perspective view of the arrangement of FIG.
4a sectioned on line IVB-IVB of FIG. 4a;
[0019] FIG. 5a shows a perspective view of a sectioned outer member
of the valve body of the metering valve of FIG. 1;
[0020] FIG. 5b shows a perspective view of the outer member of FIG.
5a from a different angle;
[0021] FIG. 6 shows a perspective view of an outer seal of the
metering valve of FIG. 1;
[0022] FIG. 7a shows a plan view of the outer member of FIG. 5a
moulded with the outer seal of FIG. 6; and
[0023] FIG. 7b shows a perspective view of the arrangement of FIG.
7a sectioned on line VIIB-VIIB of FIG. 7a.
[0024] The metering valve 10 of the present invention, as shown in
FIG. 1, is connectable in use to a dispensing container (not shown)
in which a product to be dispensed in metered doses is stored. The
product may, for example, be a liquid or a drug substance held in
suspension or in solution and expelled using a volatile liquified
propellant such as a CFC or an HFA or blends thereof.
[0025] The valve 10 is held in position to seal the dispensing
container by a cap or ferrule 13 which is crimped to the open neck
of the container.
[0026] The valve 10 comprises a valve stem 20 which extends
coaxially within a generally cup-shaped outer member 17 so as to be
externally accessible.
[0027] In the following description and claims the term "inner" is
used to mean being relatively remote from a dispensing end of valve
stem 20. The term "outer" is used to mean being relatively
proximate a dispensing end of valve stem 20.
[0028] The valve 10 further comprises an inner member 16, a gasket
14, an inner seal 15 and an outer seal 18.
[0029] The inner member 16 and outer member 17 together define a
valve body 12.
[0030] The outer member 17, preferably of a polymeric material, has
at an outer end a base 21, in which is located an aperture 22, and
side walls 23 defining an open end to the outer member 17.
Sandwiched between the base 21 of the outer member 17 and the
ferrule 13 is the outer sliding seal 18 of an elastomeric material
which also has an aperture therein.
[0031] The valve stem 20, preferably of a polymeric or metallic
material, has at one end a generally hollow section 25 defining a
dispensing channel in which portion 25 is located a port 26, and at
its other end a piston 27 having a larger cross-sectional area than
the hollow section 25. The hollow section 25 extends from the
container and the piston 27 is received in and is slidable relative
to the outer member 17. The external diameter of the piston 27 is
selected to be smaller than the internal diameter of the outer
member 17 thus leaving a radial clearance 28.
[0032] The inner member 16 covers off the open end of the outer
member 17 and is secured in position by a flange portion 30 which
is clamped between the ferrule 13 and the gasket 14 when the valve
10 is assembled with the dispensing container. The inner member 16
has entry ports 31 to allow the liquified product to access the
inside of the valve 12.
[0033] A return spring 19, preferably of stainless steel, is
located between a base of the inner member 16 and the piston 27
thereby urging the piston 27 into contact with the base 21 of the
outer member 17.
[0034] In known metering valves the inner member, outer member,
gasket, inner seal and outer seal are provided as separate
components which must be assembled with one another during assembly
of the metering valve 10.
[0035] According to the present invention a co-moulded inner
member, generally referenced in the accompanying Figures by numeral
11, and a co-moulded outer member, generally referenced in the
accompanying drawings by numeral 61, are provided.
[0036] The co-moulded inner member 11 and co-moulded outer member
61 together define a valve body 12.
[0037] The co-moulded inner member 11 comprises an inner member 16,
inner seal 15 and gasket 14 formed as a single unitary component by
means of a co-moulding manufacturing process. The co-moulded outer
member 61 comprises an outer member 17 and an outer seal 18 formed
as a single unitary component by means of a co-moulding
manufacturing process.
[0038] The co-moulded inner member 11 is formed using two moulding
steps. A first mould shape is formed by a mould tool and a first
material is injection moulded into the mould shape to form the core
component of the inner member 16 as shown in FIGS. 2a and 2b. A
second mould shape is then formed which contains the core
component. Preferably the same mould tool is used to form the first
and second mould shapes by means of actively controlled components
of the mould tool which may be moved relative to one another to
vary the configuration of the mould shape and to provide the
necessary flow paths for the injection process.
[0039] A second material is then injected into the second mould
shape to form the inner seal 15 and gasket 14. Since the core
component of the inner member 16 is present in the second mould
shape the inner seal 15 and gasket 14 are intimately moulded with
the inner member 16 such that a strong mechanical bond is achieved
between the inner seal 14, gasket 15 and inner member 16 as shown
in FIGS. 4a and 4b.
[0040] The form of the gasket 14 and inner seal 15 is shown in FIG.
3 and the form of the finished co-moulded valve body 11 is shown in
FIGS. 4a and 4b. The gasket 14 and inner seal 15 are provided with
keyed portions 33 which matingly engage with keyways 34 in the
inner member 16. The keyed portions 33 and keyways 34 improve the
mechanical bonding between the inner member 16 and the gasket 14
and inner seal 15.
[0041] Similarly, the co-moulded outer member 61 is formed using
two moulding steps. A first mould shape is formed by a mould tool
and a first material is injection moulded into the mould shape to
form the core component of the outer member 17 as shown in FIGS. 5a
and 5b. A second mould shape is then formed which contains the core
component. Preferably the same mould tool is used to form the first
and second mould shapes by means of actively controlled components
of the mould tool which may be moved relative to one another to
vary the configuration of the mould shape and to provide the
necessary flow paths for the injection process.
[0042] A second material is then injected into the second mould
shape to form the outer seal 18. Since the core component of the
outer member 17 is present in the second mould shape the outer seal
18 is intimately moulded with the outer member 17 such that a
strong mechanical bond is achieved between the outer seal 18 and
outer member 17 as shown in FIGS. 7a and 7b.
[0043] The form of the outer seal 18 is shown in FIG. 6 and the
form of the finished co-moulded outer member 61 is shown in FIGS.
7a and 7b. The outer seal 18 is provided with keyed portions 63
which matingly engage with keyways 64 in the outer member 17. The
keyed portions 63 and keyways 64 improve the mechanical bonding
between the outer member 17 and the outer seal 18.
[0044] An advantage of this method of forming the co-moulded inner
member 11 and co-moulded outer member 61 is that a first material
may be used to form the inner member 16 and outer member 17 and a
different material used to form the sealing elements, namely the
gasket 14, inner seal 15 and outer seal 18. Thus the optimum
material for each portion of the metering valve 10 may be utilised.
A further advantage is that the finished co-moulded inner 11 and
co-moulded outer member 61 are single unitary components wherein
there is no risk of the gasket 14, inner seal 15 and outer seal 18
becoming detached during manipulation and assembly with the
remainder of the metering valve 10. Thus, the ease of assembly of
the metering valve is much improved and the number of assembly
steps required in assembling the metering valve is significantly
reduced. This has consequential time and cost savings.
[0045] The inner member 16 and outer member 17 may be formed, by
way of example only, from any of:
[0046] acetal;
[0047] nylon; and
[0048] polyester.
[0049] The outer member 17 and inner member 16 may be formed from
different materials.
[0050] The gasket 14, inner seal 15 and outer seal 18 may be formed
by way of example only, from any of:
[0051] polyurethane (aromatic polyether or aromatic polyester);
[0052] thermoplastic vulcanizates (being a blend of a plastic part
selected from polypropylene, polyethylene or polystyrene and a
crosslinked elastomer selected from polyisprene, polybutadiene,
polyethylene propylene, polychloroprene, polyacrylonitrile
butadiene, polyisobutyl or other crosslinkable elastomers);
[0053] polystyrene polyethylenebutylene block copolymers;
[0054] polystyrene polybutadiene block copolymers;
[0055] thermoplastic polyolefin (such as ethlyene propylene
rubber);
[0056] co polyether ester;
[0057] polyether block amides; and
[0058] polyethylene copolymers.
[0059] The outer seal 18 may be formed from a different material
compared to the inner seal 15 and gasket 14.
[0060] In use, the valve stem 20 of the metering valve 10 is
displaced axially relative to the remainder of the valve 10 against
the bias of spring 19. As this occurs, a temporary chamber is
created between the valve stem 20 and the outer member 17. Product
flows through the radial clearance 28 between the piston 27 and the
outer member 17 and flows into the chamber until a lower edge of
the piston 27 contacts the inner seal 15 of the co-moulded inner
member 11. A liquid-tight seal is created at that point of contact
which prevents further ingress of product. The metered dose of
product to be dispensed is defined by the volume of the chamber and
the clearance 28. Further depression of the valve stem 20 causes
the port 26 in the hollow section 25 of the valve stem 20 to pass
through the outer seal 18 and into the chamber. The preferred
propellant systems are liquified gases or combinations thereof
having boiling temperatures significantly below room temperature.
As a result, the product boils evacuating the contents of the
chamber through the port 26 into the dispensing channel in the
hollow section 25 of the valve stem 20 thus providing an exit path
for the product.
[0061] Release of the valve stem 20 allows the spring 19 to recover
thereby forcing the valve stem 20 to return to its rest position
and the metering chamber disappears as the piston 27 approaches the
base 21 of outer member 17.
[0062] In another embodiment the inner seal 15, outer member 17 and
outer seal 18 may be formed as a single unitary component by means
of a co-moulding.
[0063] Whilst the co-moulded inner member 11 and co-moulded outer
member 61 have been described in the above embodiment for use in a
metering valve having a temporary metering chamber, it should be
appreciated that the co-moulded inner member 11 and co-moulded
outer member 61 are also suitable for use in metering valves in
general, for example those having permanent metering chambers.
* * * * *