IMPROVEMENT OF SPLIT VALVES
The present invention relates to valves, and in particular, but not exclusively, to
valves for controlling, charging, discharging and/or regulating the flow of
powders and/or fluids.
Valves, such as split butterfly valves, are available in many designs and used
widely for processes where product containment is required to prevent product
exposure to environment and personnel working in close proximity of the product.
The split valves arc designed pre-dominantly for handling and contained transfer
of solid state powders, granular material, liquids, slurries and the like.
Split valve design allows the valve to be split open into two halves, commonly
called alpha and beta halves, or active and passive halves. The valve design is
such that when split, the two halves keep the contents on either side sealed and
contained.
Similar to the split butterfly valve, a split ball valve can also be used for contained
transfer of solids and more commonly liquids. Historically, these valves have
mainly been used in pharmaceutical and biotech industries for non-sterile
operations.
In sterile equipment design, full systems need to be sterilised or decontaminated
and, once sterilised or decontaminated, it is important to ensure sterility is
maintained throughout the processing cycle, for example, adding of materials,
discharging of materials, any process transfers between systems etc.
Split valves can be sterilised or decontaminated via a number of known methods,
which include autoclaving. passing steam through the open valve, or passing other
gases, such as vapourised hydrogen peroxide, through them prior to any product
coming in contact with the internal surfaces or product contact parts.
Unfortunately, when one of these conventional known valves is split, sterility is
lost, as some of the critical surfaces of the valve and seats, when split into two
halves, become exposed to the outside surrounding non-sterile atmosphere and
contaminated. If the split valve is subsequently re-docked, and opened up for
transfer of material, the entire system can lose sterility and result in product
contamination.
In the manufacture of pharmaceuticals, chemicals or biological material, effective
containment is essential for the safe and hygienic handling of such compounds
and materials. At each stage of the manufacturing process, handling must be
controlled and managed to provide optimum protection for the operator and for
maintaining the integrity of the product.
The material being handled is often hazardous to health, owing to the increasing
potency of many new active pharmaceutical ingredients (APIs). Pharmaceutical
and bio-manufacturing products are often manufactured under strict controls
against product contamination. This is because the products are often for human
consumption and the industries are heavily regulated by bodies like the FDA
(Food and Drag Adininistration) in the United States and the MHRA (Medicines
and Healthcare products Regulatory Agency) in the United Kingdom.
Furthermore, the APIs may, in sufficient quantities, be hazardous to the health of
an operator. It is therefore necessary to avoid direct contact between an operator
and the potentially hazardous material.
T o avoid such direct contact, there is an increasing requirement to mount
containment enclosures around process equipment. However, the design of such
enclosures must minimise any hindrance to the operation of the equipment When
using a split valve assembly, this can become difficult for an operator to handle in
such contained environments.
In addition, at the conclusion of each processing operation, the interior surfaces of
the structure enclosing the processing zone must be thoroughly cleaned by the
operator prior to a further processing operation t o minimise the risk of crosscontamination.
Consequently, the pharmaceutical manufacturing industry
demands good containment performance to achieve acceptable operator exposure
levels.
For handling a solid (e.g. powder) or liquid product of a sensitive or hazardous
(e.g. toxic) nature in a processing zone, there are available a number of different
types o f containment assembly. One such conventional containment assembly is a
barrier isolator with gloved access to the processing zone in which a product
and/or handling equipment may be manipulated. A barrier isolator may offer two
fold protection, namely the use of glove ports to maintain a physical barrier
between the product and the operator and an extraction fan system to create an air
flow for removing airborne particles from the processing zone and capturing the
particles by means of filters. In this manner, a barrier isolator can achieve high
containment typically down to nanogram level.
However, isolators designed for containment and sterility combined together,
maintaining a sterile and sealed environment, both for the integrity of the material
being handled and an operator's health, can be very expensive.
PCT/GB 10/050901 discloses a split butterfly valve having two valve halves: a
passive and an active. Each valve halve has a housing having a valve seat and a
disc. The disc is displaced to open and close the valve and forms a seal with the
valve seat in the closed configuration. In use, the passive and active are brought
together and an intermediate configuration is obtained where the two halves of the
valve are docked and form a chamber between the discs. A steril ising or
decontaminating medium is introduced io clean the surfaces of the discs to
prevent contamination. The two valve halves are then fully engaged and the discs
arc then free to open to transfer material therebetween.
However, such systems in certain applications need to operate under high pressure
and be capable of holding pressure between the active and passive disc when the
two valves halves arc separated in the undocked configuration and when docked
but in the intermediate configuration where a chamber or sealed void is formed
between the discs of the valve halves. The ability to hold pressure would be
particularly advantageous as a gas could be used to decontaminate the surfaces of
the dises and valve halves in the intermediate configuration or sealed void.
However, with known split valves there is a propensity for material being
transferred between the valve halves, such as powder or the like, to become
trapped between the disc and the sealing surface of the valve seats. This in turn
causes the valve seal to fail and prevents sterilising or decontaminating medium
from being introduced to the sealed void under pressure as the sterilising or
decontaminating medium would contaminate the material to be transferred
between the valve halves, bypassing the valve disc where the seal has failed.
Failure of the valve as described above can also lead to contamination of the
surrounding environment and/or the material to be transferred, which in many
cases can be sensitive material requiring strict containment.
It is an object of the present invention to overcome or alleviate one or more of the
problems associated with the prior art.
in accordance with the present invention, there is provided a split valve assembly
comprising two valve portions complementarily shaped such that the first can
sealingly engage with and co-operate with the second to allow the movement of
material therethrougli, each valve portion comprising a housing, a valve scat and a
valve closure member moveable between a first position in which the valve
closure member s displaced from the valve seat and the valve is open, and a
second position in which the valve closure member co-operates with the valve
seat and the valve is closed, a sealing surface formed therebetween, wherein the
assembly has a first configuration in which the iirst and second valve portions
engage with one another, the valve closure members being closed, and the valve
closure members being disposed a distance apart defining, with the housing, a
chamber therebetween, which is capable of being sealed from the surrounding
environment, having an inlet and an outlet through which sterilising or
decontaminating medium may pass, and a second configuration in which the valve
closure members engage with one another and are movable from their first to their
second position, and a third configuration in which the two valve portions are
disengaged from one another, and wherein each valve portion has means for
cleaning the sealing surface between said valve seat and valve closure member.
Preferably, in the third configuration the two valve portions are undoeked, in the
first configuration the two valve portions arc partly docked and in the second
configuration the two valve portions are completely docked.
The valve of the present invention is able to operate in a complete sterile or
decontaminated manner, by use of an 'in situ' sterilisation or decontamination
step applied before completion of each docking (i.e. when n said first
configuration), regardless of how many times the valve is split open and redocked,
i.e. engaged and disengaged, ensuring sterile or near sterile conditions o n
product or material contact surfaces.
The present invention allows the valve to have a capability to have an
intermediate stage, a first configuration,, during docking that allows a chamber
which can be isolated from the surrounding environment to be formed between
the surfaces which have been exposed to the atmosphere and which are not
sterilised or decontaminated. These surfaces need to be sterilised or
decontaminated before they can become exposed to the internal sterile parts of the
assembly and material which may pass therethrough when the valve is fully
docked and open so as to prevent contamination.
The means for cleaning the sealing surface may comprise, in the case of a split
butterfly valve, for example, the valve closure member being capable of rotation
beyond the formation of a seal between the valve closure member and the valve
seat. In such an embodiment, a seal between the valve closure member and the
valve scat is obtained when the plane of the valve closure member is
[substantially] perpendicular to the plane of the valve seat and the direction of
flow of material. Preferably, the means for cleaning the sealing suiface comprises
the rotation of the vafve closure member more than 90 degrees with respect to the
plane of the valve seat. The 'over-rotation' beyond 90 degrees allows the valve
closure member to scrape off any residual material, such as powder that may be
disposed a the sealing surface of the valve seat to ensure that when the valve
closure member is subsequently in its closed configuration, perpendicular to the
valve seat, there is a good seal therebetween and sterilising or decontaminating
medium can be introduced under pressure without fear of the seal failing.
The means for cleaning the sealing surface may alternatively or additionally
comprise one or more protuberance disposed on the valve closure member. The
one or more protuberance preferably are disposed such that they can engage with
the scaling surface of the valve seat In use, the protuberancecan displace any
residual material located at the sealing surface to ensure a good seal between the
valve closure member and the valve seat. The one or more protuberance
preferably extends around the perimeter of the valve closure member. More
preferably, in one embodiment, the one or more protuberance extends around the
circumference of the valve closure member.
Preferably, the protrubrance forms an abrasive surface for dislodging any residual
material located at the sealing surface of the valve housing.
Preferably, the one or more protrubrance comprises any one or more of one or
more ridges, one or more dimples or the like.
The present invention allows sterilisation or near sterilisation to be maintained
throughout the process of several product or material transfers, and is capable of
allowing several dockings and un-dockings (engagement and disengagement),
without compromising the sterility or near sterility of the material to be
transferred or internal process equipment upon which the valve portions of the
present invention may be mounted. The chamber may also be cleaned using fluid
gases or fluids before and after the sterilisation step, or in any sequence during the
engagement/ disengagement cycle.
Each valve portion of the assembly may be mountable on a vessel for containing
material, conveyance means, such as a hose, for conveying material and/or other
process equipment known to the art. The means for mounting the valve portions
may comprise any means known to the art, such as for example a screw thread,
interference fit, bayonet attachment etc. In an alternative embodiment, the valve
portions may be integrally formed with a vessel or conveyance means.
The inlet and outlet of the chamber may be closed once the movement from the
first to the second configuration is complete. In so doing, the assembly ensures
that the material being transferred therethrough is not contaminated with
sterilising or decontaminating medium.
The valve scat and va!ve closure member are preferably complementarity shaped
to ensure that a seal is formed when the valve closure member is closed.
The valve assembly may be a split butterfly valve, split ball valve, any other split
valve or quick release coupling known to the art. Preferably, the assembly is a
split butterfly valve.
The inlet and/or outlet of the chamber may be formed in the housing of one of the
valve portions. Preferably, both the inlet and the outlet are formed in the housing
of one of the valve portions.
Preferably, the valve portions form a mating pair, one being a male valve portion,
the other female. The inlet and/or outlet may be formed in the housing of one or
both of the valve portions. More preferably, the inlet and outlet for the chamber is
formed in the female valve portion.
In one embodiment, the chamber has circular cross section.
The valve closure member may be pivotally mounted within the valve hottsmg by
means of opposed spindles projecting from the closure member and located in
corresponding recesses within the valve housing. The valve housing may be
provided with a valve seat and the valve closure member can be pivotable into and
out of engagement with the valve seat to close and open the valve respectively.
Preferably, the spindles are integrally formed with the valve closure member.
Advantageously, the spindles and the valve closure member, may be machined
from a single piece of material.
In one embodiment, the valve closure member being pivotable beyond the
position in which further displacement is normally prevented by engagement with
the valve seal, the valve may further comprise biassing means for brassing the
valve closure member into a position beyond its normal closed position, whereby
in the absence of the valve seal the valve closure member will engage the valve
seat
In order to ensure that the chamber, defined by the housing of one or both of the
first and second valve portions and the valve closure members, is capable of being
sealed from the surrounding environment, an O ring and/or inflatable seal may be
disposed on the housing of one or both of the valve portions. This ensures that
during cleaning, whereby sterilising or decontaminating medium is passed
through the chamber when the assembly is in its first configuration and when
material is transferred through the valve there is a significantly reduced possibility
of cross-contamination between the chamber and the surrounding environment,
thus ensuring that the material transferred is not contaminated and maintaining
operator safety.
The sterilising or decontaminating medium suitable for use with the assembly of
the present invention may comprise a fluid, vapour and/or gas. Preferably, the
sterilising or decontaminating medium is introduced under pressure. Preferably,
the medium is vaporised hydrogen peroxide, filtered nitrogen, filtered air and/or
water. For materials sensitive to heat, vaporised hydrogen peroxide is preferably
used, whilst for materials not generally heat sensitive, steam under pressure at
temperatures up to 135 oC can be used. Pressurised and filtered air and/or
nitrogen or other such gases may be used as a cleaning medium to blow any
debris, particles, residues, impurities etc. out of the chamber in lieu of or in
combination with other sterilising or decontaminating media. If it is to be used as
a sterilising or decontaminating medium, then the aim is preferably filtered to
remove potential contaminants.
The outlet may be connected to filter means and/or a catalyst to treat any waste
stream from the chamber. Preferably, when vapourised hydrogen peroxide is used,
the outlet is connected to a catalyst to treat the waste stream.
During use, the assembly may be switched from the first to the second
configuration to allow material to be transferred therethrough. Once the material
has been transferred, the assembly is switched back to the first configuration and
the surfaces which are to be exposed to the surrounding environment cleaned
before disengaging the two valve portions so as to prevent the operator from being
exposed to any residual material left on the exposable surfaces, and thus ensuring
operator safety.
In accordance with a further aspect of the present invention, there is provided a
method of moving a material from one vessel to another without exposing the
material to the surrounding environment comprising the use of a valve assembly
as described hereinabove, the method comprising the steps of:
a) Engaging the valve portions such that the assembly conforms to its first
configuration;
b) optionally cleaning the chamber;
c) sterilising or decontaminating the chamber;
d) displacing the valve portions such that the assembly conforms to its
second configuration; and
e) opening the valve to allow the movement of material therethrough.
Once the requisite quantity of material has been transferred, the method may also
comprise the subsequent steps of:
f ) displacing the valve portions such that the assembly conforms to its first
configuration;
g) optionally cleaning the chamber;
h) optionally sterilising or decontaminating the chamber; and
i) disengaging the valve portions.
By way of example only, a specific embodiment of the present invention will now
be described, with reference to the accompanying drawings, in which:
Fig. ί is a cross sectional side elevation of two valve portions of a valve assembly
engaged with one another in an intermediate configuration in accordance with the
present invention;
Fig. 2 is a cross sectional perspective view of a valve assembly in its first
configuration in accordance with the present invention; and
Fig. 3 shows the edge of a valve closure member in accordance with the present
invention.
Referring firstly to Figs. 1 to 3, the valve assembly 10 comprises two valve
portions, an upper and lower valve portion 12,14, each having a valve housing
indicated generally at 16, 18 which are generally annular and a valve closure
member 20, 20' which is pivotally mounted within the housmg. The valve closure
member 20,20' is in the form of an annular disc and is provided with spindles
22,22' by means of which the valve closure member is pivotally mounted within
the housing. The valve closure member 20,20' and the spindles 22,22'are
machined fr om a single piece of metal.
One of the spindles 22 of the lower valve closure member 18 is adapted to be
received by a further spindle (not shown) of actuator 26, whilst the housing of
lower valve portion 18 has a bore receiving the other spindle 22'. Thus, the
annular disc is joumalled for rotation on the spindles 22,22' and is moved by
rotation of the spindle of actuator 26. A manual actuator 26 is received on an
opposite end to the annuiar disc of the spindle. A pneumatic or automatic actuator
can be used in an alternative embodiment.
The valve closure member 20,20' is cngagcable with and disengageable from an
annuiar valve seat in the form of an annular seal 28,28' The seal comprises a
EPDM annular abutment portion (alternatively, perfluoroelastomer or any other
suitable material can be used) which, in use, engages the valve closure member
20,20'.
The valve assembly comprises releasably securable valve portions 16, 18 via
locking ring 3 1 which prevents the valve portions from disengaging.
Alternatively, in an alternative embodiment, the valve portions can be releasably
locked using a moveable pin which can engage with a complimentary shaped bore
to lock the two valve portions together as described in PCT/GB 10/0502288.
Furthermore, in another embodiment the docking system is so designed to hold
the two halves in the correct position without the use of a locking ring or locking
mechanism.
The outer end face 32,32' of each of the valve housing portions 16, 18 is planar
and in use each face is connected to, for example, adjacent piping sections or a
vessel in a manner well known to in the art and a through passage is formed by
means of, for example, aligned bores. Upper valve portion Id has an annular
recess 34 which receives O-ring 42. When the valve portions 16, 18 are brought
together, O-ring 42 co-operates with the inner side wall 43 of the housing of valve
portion 18 to form a seal which is impoitant when the valve is in its intermediate
configuration, as explained below.
The abutment of the two valve housing portions 16,18 form a mating pair such
that the upper valve portion 16 is mounted within the lower valve housing portion
18, the upper valve portion 16 being male and the lower valve portion 18 being
female. In a first configuration (see Fig. 2) the two valve portions are engaged,
such that the chamber is sealed from the surrounding environment and that
material to be transferred through the valve will not be contaminated by the
surrounding environment. Tn Fig. 1 the valve assembly is in ts intermediate
configuration and define the two valve portions 16, 18 define a chamber 29
therebetween. The chamber is defined by the valve closure members 20,20' and
the seal formed between inner side wall 43 of valve portion 18 and O-ring 42.
ϊhthis way, the two portions of the valve 16, 18 can be sealed with respect to the
exterior environment whilst defining a chamber between valve closing members
20,20' and the housings of valve portions 16, 18 by means of the co-operation
between O-ring 42 and side wall 43. Any misalignment of the two body halves
may be overcome in several ways, a preferred way being to provide longitudinally
captivated locators between the two body halves.
Lower valve portion 18 has a tangential inlet (not shown) and a tangential outlet
46 which communicate with chamber 29 when formed by bringing the two valve
portions 16,1 8 together in the first configuration. The inlet and outlet are disposed
about the radius of chamber 29. Sterilising or decontaminating medium in the
form of a liquid, gas and/or vapour will be fed into the chamber 29 via inlet 44
under pressure. The sterilising or decontaminating medium can then be removed
from the chamber 29 via outlet 46 which may be connected to a vacuum pump,
fan via a filter and/or catalyst to assist in the removal of sterilising or
decontaminating medium and debris.
The valve closure members are adapted to be pivotable through more than 90
degrees, and when in its fully open position the profile of the inner face 50,50' of
the valve closure member 20,20' corresponds with the profile of the through bore
of the valve housing, thereby creating no restrictions for the flow of fluid or other
material.
It is the rotation beyond 90 degrees of the engaged discs 20, 0' that enables the
edge of the discs to ensure that any material at the sealing surface left from a
previous material transfer to be scraped from the site. Fig. 2 shows the angle of
rotation of engaged discs 20,20': the angle between lines X and Y being 90
degrees and the angle between lines X and Z being greater man 90 degrees. When
the valve assembly is in its intermediate configuration, the chamber 29 can be
subjected to pressurised sterilisation or decontamination without any risk of
leakage of the sterilising or decontaminating medium beyond the sealing surface
and contaminating the material to be transferred.
Fig. 3 shows an alternative embodiment having a plurality of ridges 60 disposed
on the side 62 of a disc 20, which could additionally or alternatively be also
disposed on disc 20'. Each ridge acts to scrape any residual material from the
sealing surface to ensure an effective seal once the valve is closed.
When the valve closure members 20,20' have been exposed to the sterilising or
decontaminating medium for a sufficient time to ensure that any impurities or
contaminants have been removed or neutralised, any residual sterilising or
decontaminating medium can be expelled using pressurised filtered air introduced
via inlets 44,44'. The valve assembly can then be fully engaged in its second
configuration, whereby seats 28,28' mate to form a seal and valve closure
members 20,20' contact one another and can rotate to open each valve portion
respectively, which are sealingly engaged thereby allowing the passage of
material therethrough without the material becoming contaminated. Rotation of
the spindles 22, 22' of the lower valve closure member 20' will result In rotation
of the upper valve closure member 20'.
The valves of the present invention are able to operate in a complete sterile or
near sterile manner, with an in situ sterilisation or decontamination step before
and after each docking, regardless of how many times the valve is split open and
re-docked, ensuring sterile or near sterile conditions on product contact parts.
The invention allows the valve to have a capability to have an intermediate stage,
a first configuration, during docking that allows a barrier to be present between
internal process sterile areas and the previously exposed areas which are not
sterilised or decontaminated but need to be sterilised or decontaminated before
they can become part of the internal sterile parts when the valve is fully docked.
These "intermediate transit contact parts" have another barrier to the outside; the
parts and surfaces beyond this barrier do not require sterilisation or
decontamination.
These barriers can be created by any combination of seals, gaskets, o rings, seats
and/or inflatable seals.
In the intermediate docking position, the valve allows the two halves of the
butterfly disc to be separated by a nominal space which is wide enough to allow
irrigation of all surfaces by either steam, cleaning agents, sterilising or
decontaminating fluids, or gases such as vapourised hydrogen peroxide, or
combinations of any or all.
The valve also has inlet entry points where these sterility or decontamination
liquids, gases or vapours can enter , freely low over all intermediate surfaces,
saturate all surfaces and then leave the valve intermediate areas through exit
points where the sterility or decontaminating medium can either he re-circulated
or exhausted as once through fluids.
Once the sterility or decontamination cycle is completed, the valve can be fully
docked, engaged, into its second configuration. Once fully docked, the
intermediate parts, which are now sterile or decontaminated, can become part of
the internal process contact parts. Opening the valve for flow allows material to
pass through the sterilised or decontaminated surfaces, in contrast to the prior art.
Once transfer is completed, before final undocking, disengagement, of the valve
portions, a clean in place (CEP) cycle can be carried out to remove any remaining
debris of product from the areas which later will become exposed to the
atmosphere, thereby providing high containment of the drug from operator
exposure. The valve can be closed and returned to its intermediate position, first
configuration, whereupon any residual material left on the surfaces can be
cleaned using CJP gases or fluids introduced to and removed from the chamber
via inlets 44, 44' and outlets 46, 46'. Once "cleaned" the valve can be undocked
and split into two halves.
When the valve is split open into two halves, any material disposed within a
vessel etc. will maintain its sterility or near sterility as each valve poition is sealed
from the surrounding atmosphere by the valve closure members.
The invention is not restricted to the details of the foregoing embodiments. For
example, the valve actuator may be replaced with a different actuator, such as an
automated actuator.
An alternative embodiment of the present invention replaces the butterfly valve
closure members of the valve with ball closure members.

CLAIMS
1. A split valve assembly comprising two valve portions complementarity shaped
such that the first can sealingly engage with and co-operate with the second to allow
the movement of material therethrough, each valve portion comprising a housing, a
valve scat and a valve closure member moveable between a first position in which the
valve closure member is displaced from the valve seat and the valve is open, and a
second position in which the valve closure member co-operates with the valve seat
and the valve is closed, a sealing surface formed therebetween, wherein the assembly
has a first configuration in which the first and second valve portions engage with one
another, the valve closure members being closed, and the valve closure members
being disposed a distance apart defining, with the housing, a chamber therebetween,
which is capable of being sealed from the surrounding environment, having an inlet
and an outlet through which sterilising medium may pass, and a second configuration
in which the valve closure members engage with one another and are movable from
their first to their second position, and a third configuration in which the two valve
portions are disengaged from one another, and wherein each valve portion has means
lor cleaning the sealing surface between said valve seat and valve closure member.
2. A valve as claimed in claim 1 wherein in the third configuration the two valve
portions arc undocked. in the first configuration the two valve portions are partly
docked and in the second configuration the two valve portions are completely docked.
3. Avalve as claimed in claim 1 or 2 wherein each valve portion of the assembly is
mountable on a vessel for containing material or conveyance means.
4. A valve as claimed in claim 3 wherein the means for mounting the valve portions
comprises at least one of a screw thread, an interference fit or a bayonet attachment.
5. A valve as claimed in claim 2 or 3 wherein the valve portions are integrally formed
with a vessel or conveyance means.
6 . A valve as claimed in any one of the preceding claims wherein the inlet and outlet
of the chamber is closed once the movement from the first to the second configuration
is complete.
7. A valve as claimed in any one of the preceding claims wherein the valve seat and
valve closure member are preferably complenientartly shaped to ensure that a seal is
formed when the valve closure member is closed.
8. A valve as claimed in any one of the preceding claims wherein the valve assembly
is a split butterfly valve, split ball valve or quick release coupling.
9. A valve as claimed in claim 8 wherein the valve assembly is a split butterfly valve.
10. A valve as claimed in any one of the preceding claims wherein the inlet and/or
outlet of the chamber is formed in the housing of one of the valve portions.
11. A valve as claimed in any one of the preceding claims wherein the valve portions
form a mating pair, one being a male valve portion, the other female.
12. A valve as claimed in any one of the preceding claims having circular cross
section.
13 A valve as claimed in claim 12 wherein the inlets and/or outlets are tangentially
disposed with respect to the circumference of the chamber which is formed by the
first and second valve portions.
14. A valve as claimed in any one of the preceding claims wherein the valve seat
comprises a seal member.
15. A valve as claimed in claim 14 wherein the seal member comprises an abutment
portion and a resiliently deformable portion located between the abutment portion and
the valve housing.
16. A valve as claimed in any one of the preceding claims wherein the valve closure
member is pivotable beyond the position in which further displacement is normally
prevented by engagement with the valve seal, the valve further comprises biassing
means for biassing the valve closure member into a position beyond its normal closed
position, whereby in the absence of the valve seal the valve closure member will
engage the valve seat.
17. A valve as claimed in any one of the preceding claims wherein the chamber,
defined by the housing of one or both of the first and second valve portions and the
valve closure members, is capable of being sealed from the surrounding environment,
by means of an O ring and/or inflatable seal.
18. A valve as claimed in any one of the preceding claims wherein the sterilising
medium comprises a fluid, vapour and or gas.
19. A valve as claimed in claim 18 wherein the medium is vaporised hydrogen
peroxide, filtered nitrogen, filtered air and/or water.
20. A valve as claimed in any one of the preceding claims wherein the outlet is
connected to filter means and or a catalyst to treat any waste stream from the
chamber.
21. A method of moving a material from one vessel to another without exposing the
material to the surrounding environment comprising the use of a valve assembly as
described hereinabove, the method comprising the steps of:
a ) Engaging the valve portions such that the assembly conforms to its first
configuration:
b) optionally cleaning the chamber.
c ) sterilising or decontaminating the chamber;
d ) displacing the valve portions such that the assembly conforms to its second
configuration: and
e ) opening the valve to allow the movement of material therethrough.
22. A method as claimed in claim 2 1 wherein once the requisite quantity of material
has been transferred, the method also comprises the subsequent steps of:
f) displacing the valve portions such that the assembly conforms to its first
configuration;
g) optionally cleaning the chamber.
h) optionally sterilising or decontaminating the chamber; and
i) disengaging the valve portions.
23. A coupling assembly comprising two coupling portions complementarily shaped
such that the first can sealingly engage with and co-operate with the second to allow
the movement of material therethrough, each coupling portion comprising a housing,
a coupling seat and a coupling closure member moveable between a first position in
which the coupling closure member is displaced from the coupling seat and the
coupling is open, and a second position in which the coupling closure member co¬
operates with the coupling seat and the coupling is closed, wherein the assembly has a
first configuration in which the first and second coupling portions engage with one
another, the coupling closure members being closed, and the coupling closure
members being disposed a distance apart defining, with the housing, a chamber
therebetween, which is capable of being sealed from the surrounding environment,
having an inlet and an outlet through which sterilising medium may pass, and a
second configuration in which the coupling closure members engage with one another
and are movable from their first to their second position, and a third configuration in
which the two valve portions are disengaged from one another.