Abstract:
Fluid transfer apparatus including a body having a bore formed through at least a portion of its interior. Contained within the bore is a movable plunger that moves without changing the axial dimensions of the body. A first end of the body contains a face designed to be attached to an upstream component. A second end of the body is connected to a downstream component such as a filter, pipeline, etc. A first end of the plunger, when it is in the closed position, is in alignment with the face of the body, which combined form a steamable surface and a sterile barrier against the environment to the remainder of the interior of the body, the plunger and downstream components. An outer annular collar is rotatable relative to the body and causes the plunger to move axially within the bore from an open to a closed position.

Description:
This application is a continuation of U.S. patent application Ser. No. 12/902,430, filed Oct. 12, 2010, which claims priority of U.S. Provisional Application Ser. No. 61/280,172 filed Oct. 30, 2009, the disclosure of which is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a fluid transfer device, and a system embodying the fluid transfer device. In certain embodiments, it relates to a disposable sterile fluid transfer device in the form of a valve particularly suited for use in the pharmaceutical and biopharmaceutical industries. 
     BACKGROUND 
     In the pharmaceutical, biotechnology and even food, beverage and cosmetics industries, it is often desired to provide a processing system that is capable of handling fluids in a sterile manner. This is designed to prevent unwanted, often dangerous organisms, such as bacteria as well as environmental contaminants, such as dust, dirt and the like from entering into the process stream and/or end product. It would be desirable to have a completely sealed system but this is not always possible with the processes that take place in production. 
     There is a need for the introduction or removal of materials from the process stream in order to add components of the product, such as media or buffers to a bioreactor; withdraw samples from the process stream to check for microbial contamination, quality control, process control, etc.; and to fill the product into its final container such as vials, syringes, sealed boxes, bottles and the like. 
     Typically, the systems have been made of stainless steel and the system is exposed to live steam before use and then cleaned with chemicals such as caustic solutions after use to ensure that all contaminants are removed. 
     Steaming is the most effective means of sterilization. The use of steam in a set system is known as steaming in place or SIP. Saturated steam carries 200 times the BTU heat transfer capacity of heated air because of the latent heat released by the steam as it changes from vapor to liquid. However, several disadvantages exist with the use of steam. Any connections to or openings of the system made after the system has been steamed in place must be aseptic so as not to contaminate the system. Although this can be done using aseptic connectors this procedure increases the risk of contamination of the entire system. One typically uses alcohol wipes or an open flame to clean the components to be connected, (e.g. connecting a sample collection bag to a system after SIP has occurred) and thus minimize the risk of contamination. 
     Also, the high temperatures and pressure differentials of the steam make the selection of filter materials and components very difficult and limited and even then an accidental pressure differential at high temperatures can cause a filter, membrane or other non-steel component to fail. 
     Additionally, such systems that are reused need to undergo rigorous testing and validation to prove to the necessary authorities that the system is sterile before each use. The expense of validation as well as the cleaning regiment required is very high and very time consuming (typically taking 1 to 2 years for approval). In addition, some components are very difficult to adequately clean after use in preparation for their next use. Manufacturers are looking for ways to reduce both their costs and the time to market for their products. One possible approach is to adopt an all disposable system that is set up in a sterile fashion, used and then thrown away. 
     Biopharmaceutical manufacturers continue to prefer fully disposable filtration solutions due to reduced cleaning and capital equipment costs. Users will either purchase individual components and assemble them into the desired fluid flow path, or purchase preassembled flow paths, such as Millipore&#39;s Mobius® Solutions. Commonly these components or assemblies are pre-sterilized by the vendor using gamma irradiation. This reduces the bioburden and allows the user to achieve higher levels of aseptic assurance. 
     Although it is impossible to insure completely sterile assemblies, there are methods to reduce the risk of environmental contamination. Pre-sterilized assemblies are commonly sold with aseptic connectors, such as Millipore&#39;s Lynx® S2S, where the connections can be made in a validated sterile way. These kinds of connectors help control contamination from environment. Some customers order filter assemblies with connectors that can be directly sterilized by the customer, such as Millipore&#39;s Lynx® ST. This kind of connector acts as a valve and isolates the pre-sterilized filtration area from the environment. The methods of connection and the ability to insure sterility are of great importance and can be improved. 
     Disposable filter capsules are commonly sold pre-sterilized and packaged in the common aseptic double bag so the customer can manage bioburden by removing one bag at a time at various steps along the assembly process. However, such capsules cannot be used with non-disposable equipment because there is no simple means to sterilize both the reused and disposable components after they are assembled together. Although the filter membranes can survive steam-in-place (SIP) the capsule housing softens and may rupture during the high pressure and temperature exposure. Some manufacturers use high performance materials to withstand the extreme conditions, which incur additional product cost. Even with the use of high performance materials, the capsule must be aseptically installed. 
     In addition, in the use of a capsule filter such as by pharmaceutical manufacturers, it may become necessary to isolate a single filter form other filters, in order to retain sterility during installation, or to sterilize fluid pathways up to the capsule, for example. Also, a plurality of capsule filters is often used in parallel or in series, thereby necessitating their interconnection. An integral capsule connector that provides a parallel connection capability is advantageous in that it avoids external piping. 
     It therefore would be desirable to provide a pre-sterilized capsule that can be attached to existing reusable processing equipment, or to disposable equipment, and which can be sterilized such as by steaming-in-place while reducing environmental exposure. It also would be desirable to provide a filtration unit having an integral pre-sterilized capsule attached, as well as to provide a manifold assembly including one or more pre-sterilized capsules. 
     SUMMARY 
     The fluid transfer apparatus disclosed herein relates to a sterile transfer device for fluids (e.g., liquids or gases). In certain embodiments, the apparatus comprises a body having a bore formed through at least a portion of its interior. Preferably, it is a central axial bore formed through the entire length of the body. Contained within the bore is a movable plunger. In certain embodiments, the plunger moves without changing the axial dimensions of the body; it does not telescope. A first end of the body contains a face designed to be attached to an upstream component. A second end of the body is connected to a downstream component such as a filter, pipeline, sample bag or the like. The plunger has corresponding first and second ends. The first end of the plunger, when it is in the closed position, is in alignment with the face of the body, which combined form a steamable surface and a sterile barrier against the environment to the remainder of the interior of the body, the plunger and downstream components. An outer annular collar is rotatable relative to the body and causes the plunger to move axially within the bore from an open position to a closed position. 
     In certain embodiments, the downstream components are assembled to the device and it is placed in the closed position. The entire device and downstream components can be sterilized, such as with gamma radiation. In use the device and downstream components are attached by the face to the upstream component such as a filter outlet, a tank outlet, or a “T” of a pipe, and secured in place. The system and the face of the device are then steam sterilized in place. The device is then selectively opened when needed, establishing a sterile fluid pathway through the device to the downstream components. 
     The fluid transfer apparatus thus provides a connector that can be used in either the traditional steel system or disposable system which provides both a means for steam sterilizing the mating point of the connector to the system as well as providing a sterile downstream area or component, in pre-sterile condition, that can be disposed of after use and not be re-cleaned. The non-telescoping articulation means that actuation of the device does not result in a change in connector length, thereby enabling a user to install a capsule filter between fixed position piping. The shut-off feature and design of the face seal isolates the capsule filter from steam that can be used to sterilize the upstream or downstream components or plumbing. 
     In certain embodiments, the connector or valve includes a body having a bore, a plunger axially moveable within the bore between a valve open position and a valve close position, and a cam actuator operatively connected to the plunger such that rotation of the cam actuator causes axial movement of the plunger in the bore from the valve open to the valve closed position. In certain embodiments, the valve includes a pair of radially inwardly extending plunger engaging members and a pair of radially outwardly extending cam actuator engaging members, the members providing the connection between the cam actuator and the plunger. In certain embodiments, the cam actuator includes first and second collars, each having a groove for receiving a respective one of the radially outwardly extending cam actuator engaging members in sliding relation. 
     The fluid transfer devices enabling efficient manifolding, where multiple filters can be configured in series or in parallel. This enables, for example, the use of different grade filters in series, redundant single grade filters in series, larger total filter area in parallel, connection to disposable capsule housings, and a compacted assembly to reduce the footprint. Multiple capsule feed inlets can be interconnected and share a common feed port without the need for external manifold piping. Integrity testing of the assemblies also can be easily carried out. For example, a capsule filter can be individually integrity tested without removing it from a manifold arrangement by properly configuring the various fluid transfer devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a fluid transfer device shown in a closed position in accordance with certain embodiments; 
         FIG. 2  is a cross-sectional view of a fluid transfer device shown in an open position in accordance with certain embodiments; 
         FIG. 3  is a perspective view of the body of a fluid transfer device in accordance with certain embodiments; 
         FIG. 4  is a perspective view of a plunger in accordance with certain embodiments; 
         FIG. 4A  is a cross-sectional view of a plunger in accordance with certain embodiments; 
         FIG. 5  is a perspective view of a split ring in accordance with certain embodiments; 
         FIG. 6  is a perspective view of a collar half-ring in accordance with certain embodiments; 
         FIG. 7  is an exploded perspective view of a fluid transfer device in accordance with certain embodiments; 
         FIGS. 8A-8F  are schematic diagrams of multiple filter capsules connected in different configurations with fluid transfer devices in accordance with certain embodiments; 
         FIG. 9  is a perspective view of a filter capsule with multiple fluid transfer devices in accordance with certain embodiments; and 
         FIG. 10  is a perspective view of a fluid transfer device in accordance with certain embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Turning now to  FIGS. 1-3 , the device  2  includes a body  4  having a first end  6  and a second end  8  spaced from the first end  6 . The body  4  also has a bore  10  extending axially from the first end  6  to the second end  8 . In certain embodiments, the bore  10  is generally circular in cross section. Preferably first end  6  has an annular flange  11  that extends radially outwardly. The front sealing face of the annular flange can include an annular groove  19  for receiving an O-ring or the like (not shown) to assist in sealing the front sealing face against the component it attaches to. Preferably second end  8  also has an annular flange  11 ′ that also extends radially outwardly, and also can include a sealing face having an annular groove  19 ′ for receiving an O-ring or the like (not shown). Preferably the internal diameter of the bore  10  is substantially constant except where it tapers to a smaller diameter defined by the annular wall  21  near the first end  6 . 
     Spaced radially extending annular outer flanges  28 ,  28 ′ are positioned on the outer wall of the body  4 , as best seen in  FIG. 3 . These flanges function to position the cam actuator collars  50  as discussed in greater detail below. A pair of oppositely positioned cam slots  51 ,  51 ′, preferably oval-shaped, are formed in the body  4 , again as discussed in greater detail below. 
     The bore  10  is configured to receive a plunger  18  ( FIGS. 4 ,  4 A). In certain embodiments, the plunger  18  is configured to slide within the bore  10  upon actuation, as discussed in greater detail below. Accordingly, in certain embodiments, the plunger has a generally circular cross section, with an outside diameter slightly smaller than the internal diameter of the bore  10  in the portion of the body where the plunger slides from a valve open to a valve closed position. The length of the cam slots  51 ,  51 ′ in the axial direction can be used to set the distance the plunger  18  can travel within the bore  10  of the body  4 . The main body portion  30  of the plunger can have one or more annular grooves  31  (two shown in  FIG. 4 ) to receive an O-ring  31 ′ or the like to assist in sealing the plunger  18  against the inner wall of the body  4  or also against bore  10 . The sealing end  20  of the plunger  18  that extends axially from the main body portion  30  is shaped to seal against radially inwardly extending annular wall  21  of the bore  10 , as best seen in  FIG. 1 . Thus, the internal diameter of bore  10  in the vicinity of annular wall  21  is less than the internal diameter of bore  10  elsewhere within the body  4 . One or more O-rings  22  or the like can be placed in an annular groove in the sealing end  20  of the plunger  18  to effectuate a liquid tight seal against the annular wall  21 . The plunger  18  contains one or more openings  26  as well as a fluid channel  27  that forms a fluid connection to a downstream component or tubing (not shown). Preferably the openings  26  are equally spaced around the circumference of the plunger  18 , and are located in the tapering portion that connects the main body portion  30  to the sealing end  20 , as shown. The main body portion includes oppositely positioned apertures  52 ,  52 ′ as discussed in greater detail below. 
       FIG. 4A  illustrates another embodiment of the plunger, denoted  18 ′. In the embodiment of  FIG. 4A , additional sealing grooves are provided in the plunger body, which receive respective O-rings as shown, in order to improve sealing and thus separation of the non-sterile environment and the sterile internal volume of the fluid transfer device. 
     Preferably the entire plunger  18  is contained within the bore  10  of the body  4 , so that the length of the device  2  does not change regardless of whether the plunger is in the sealing position closing the valve (as seen in  FIG. 1 ), or is on the fully open position opening the valve (as seen in  FIG. 2 ). Accordingly, in accordance with certain embodiments, in order to actuate the plunger, a camming mechanism preferably is used. The camming mechanism includes a pair of split rings  60 ,  60 ′, as seen in  FIG. 5 , and a pair of split cam actuator collars  50 ,  50 ′, as seen in  FIG. 6 . 
     Each split ring  60 ,  60 ′ is preferably identical, and includes a radially inwardly extending plunger engaging member  62 , as seen in  FIG. 1 , and a radially outwardly extending cam actuator collar engaging member  63 . In certain embodiments, the radially inwardly extending plunger engaging member  62  and the radially outwardly extending cam actuator collar engaging member  63  can be a single member that extends in both directions through an aperture in the split ring. Alternatively, two separate members can be formed on or attached to the split ring. Preferably the radially inwardly extending member  62  is a pin that is shaped to be received by aperture  52  on the plunger main body  30 , as seen in  FIGS. 1 and 2 . Preferably the radially outwardly extending member  63  is a pin that is shaped to ride in a respective groove  70 ,  70 ′ provided in each cam actuator collar. 
     As shown in  FIG. 6 , each cam actuator collar preferably includes a knurled outer wall to assist in enabling the user to grasp and turn the collar by hand. The inner wall of each actuator collar is provided with a sloping groove  70  or  70 ′, configured to receive in sliding relation, when in the assembled condition, the radially outwardly extending member  63  of a respective split ring collar  60 ,  60 ′. 
     In the assembled state, the plunger  18  is positioned in the bore  10  of the body  4 , and each split ring collar  60 ,  60 ′ is positioned about the outer circumference of the body  4  so that the radially inwardly extending members  62  protrude through a respective cam slot  51 ,  51 ′ and are received by a corresponding aperture  52  in the plunger  18 . As a result, axial movement of each split ring collar  60 ,  60 ′ causes the radially inwardly extending member  62  to slide in its corresponding guidance slot  51  or  51 ′, as the case may be, and due to the engagement of each of the members  62  in a plunger aperture  52 , causes the plunger  18  to move axially as well. 
     The cam actuator collars  50 ,  50 ′ are fixed in place about the split ring collars  60 ,  60 ′, such that the radially outwardly extending members  63  of each split ring collar are received in sliding relation by a respective groove  70 ,  70 ′ in a cam actuator collar  50 ,  50 ′. As a result, rotation of the cam actuator collar causes the radially outwardly extending members  63  to ride in the groove  70 ,  70 ′. The cam actuator collars  50 ,  50 ′ can be fixed in place by any suitable method, such as by providing apertures  72  in each collar and fixing the two collars together with screws. At least a portion of each groove  70 ,  70 ′ is sloped with respect to horizontal, so that as the members  63  slide in the groove, there is an axial component to their movement as well. The extent of the slope, both in terms of its steepness and its length, thus can be used to limit the length of travel of the plunger  18  in the bore  10  of the body  4 . For example, in certain embodiments the slope of the grooves  70 ,  70 ′ can be gradual and constant, as shown in  FIG. 6 . In other embodiments, the grooves can have either a small or zero slope at and near the terminal ends of each collar  50 ,  50 ′, and a relatively steep slope between the portions of the small or zero slope. The groove  70  in collar  50  is positioned so that when collar  50  and collar  50 ′ are mated in the assembled condition, both ends of the groove  70  extend into the collar  50 ′. Similarly, the groove  70 ′ in collar  50 ′ is positioned so that when collar  50  and collar  50 ′ are mated in the assembled condition, both ends of the groove  70 ′ of collar  50 ′ extend into the collar  50  (e.g., at  70   a  and  70   b  shown in  FIG. 7 ). 
     In still further embodiments, a fork and pivot mechanism as shown in  FIG. 10  can be used to engage and capture the split ring collars  60 ,  60 ′, such that the overall lateral motion of the fork will cause the split ring collars to move lateral. The pivot of the fork  80  is connected to the body  4  such that as the fork handle  81  moves toward the first end  6  the fluid transfer devices moves into the closed position. To move the fluid transfer device the user moves the fork handle toward the second end  8 . The fork can be fixed in place by any suitable method, such as by providing a counter bore in each tine of the fork which engage the oppositely arranged pivots  82  and  82 ′ (not shown) and fixing the fork to the pivots such as with screws or the like. The pivots can be formed as details of the body  4  or separate pieces attached by other means such as welding or screws to body  4 . At least a portion of each fork contains oppositely arranged grooves  83 ,  83 ′ (only  83  shown) that give mechanical advantage to move the slip ring collars by engaging outwardly extending members  63  and  63 ′ (only  63  shown, and shown hatched within the grooves). The extent of the slope of the groove, both in terms of its steepness and its length, thus can be used to limit the length of travel of the plunger  18  in the bore  10  of the body  4 . 
     In alternative embodiments, the slip ring collars could be engaged to produce axial motion by the use of a rack and pinion system or a simple push-pull mechanism, although the mechanical advantage as described by the other embodiments disclosed herein would not be present. 
     In certain embodiments, the device  2  can be attached to an upstream component or pipe by sanitary flange  11  formed as part of the body  4 . The flange  11  can be attached to the upstream component or pipe by a clamp such as a Tri-Clover™ fitting, Ladish™ fitting, ClickClamp™ clamp or the like. Sterilization, such as steam treatment, can be used to sterilize the interface where necessary or desirable. 
     In certain embodiments, means may be provided enabling the user to determine if the fluid transfer device is in the open or closed position. Although visual alignment marks are common to other devices, such as the Lynx ST® connector, other embodiments improve on that means. One such embodiment is the use of multicolored components such that the slip ring collar  60  is chosen from a visual notable color and the cam actuator collar  50  has a hole or transparent window collocated with the end of the groove  70 , for instance  70   a . When the fluid transfer device is in its fully closed position, the color of  60 ′ will show through the cam actuator collar  50 . 
     The position also may be determined through electronic means whereby an electronic sensor engages a sensor reader. A RFID tag can be positioned within an axially moving component, such as sealing end  20 . A RFID reader located outside the fluid transfer device can then be used to detect a signal from the RFID tag when it is within range. The signal can be indicative of the relative position of the movable component. 
     By providing the fluid transfer device on inlet and outlet ports of filter capsules, improved means of manifolding or configuring the capsules to the user&#39;s requirements are achieved. Of particular note is the reduction of custom piping that interconnects multiple filter capsules without the need for external manifold piping. For example, as shown in  FIG. 9 , feed ( 91  and  91 ′) and permeate ( 92  and  92 ′) fluid transfer devices, can be integrated in two co-axial orientations ( 94  and  93 , respectively) with a common plane,  95 . This embodiment improves the connection methods within an existing assembly and the assembly of capsules can be slid into and out of place from any perpendicular axis, for example  96 , to the axis of the flow stream ( 97 ). 
     In a parallel configuration of capsule filters, upstream feeds  94  are connected together, producing a common feed line, as shown in  FIG. 8C . Before processing and during the installation of the filters into the users system, all the fluid transfer devices remain closed (shown as black-out). A user desiring a parallel configuration of filters would assembly them as shown in  FIG. 8C . A user may choose a parallel configuration to improve the overall filtrate capacity of the process or achieve other process improvements. During installation the single feed will connect to the fluid transfer device V- 1 A and the user&#39;s single filtrate permeate will connect to the fluid transfer device V- 3 B to the user&#39;s permeate line. During processing the fluid transfer devices are opened (shown as white-out) such that the intended filtrate will flow through V- 1 A across the left filter surface as well as flow out V- 4 A and into the second filter via V- 1 B in fluid communication with V- 4 A. Once the intended filtrate fills the upstream volume before the filter surface, the filtrate will flow across both filter surfaces and exit the two capsules. The two fluid transfer devices, V- 2 A and V- 4 B, remain closed (shown as black-out) in this configuration, forcing the filtrate out V- 3 A into V- 2 B (in fluid communication with V- 3 A) and equally out V- 3 B into the user&#39;s single permeate line. In other configurations of open and closed fluid transfer devices, the user can improve their process. With the fluid transfer devices integrated with the filter capsules the user can choose to manifold them together to form a parallel configuration of sufficient capsule filters without the need to fabricate custom manifolds. Other embodiments are within the scope of the present invention. 
     In a serial configuration of capsule filters, as shown in  FIG. 8D , a user can perform a double filtration, such that the intended filtrate is passed through two similar or dissimilar filters, which reduces the risk of a contamination due to the breach of a single filter, or other such desired processing conditions. Before processing and during installation all the fluid transfer devices remain closed. The user&#39;s feed line is connected to V- 1 A and filtrate permeate line is connected to V- 2 B. The second filter device is oriented by placing its feed fluid transfer device, V- 4 B, in fluid communication with the permeate fluid transfer device V- 3 A of the first filter. During processing certain fluid transfer devices remain closed such that the intended filtrate enters V- 1 A flowing across the filter surface and exits the first filter via V- 3 A and enters the second filter into V- 4 B in view of the fluid communication therebetween. The intended filtrate then continues to flow across the second filter surface and exits V- 2 B. Other configurations whereby the fluid transfer devices are opened and closed with the serial configuration allow users to simplify their processing. Other embodiments are within the scope of the present invention. 
     Once the fluid transfer device(s) are assembled to the capsule filter(s), the devices can be closed and terminally sterilized such as by gamma radiation by the manufacturer and supplied sterile to the user. In this condition the user will receive a pre-sterilized capsule filter which is ready for installation and use. Some filter capsules, such as Opticap® units from Millipore, do not have integrated fluid transfer devices. During installation and processing these filters must be sterilized before the intended filtrate is introduced. The user may assembly them to their system and autoclave the system or perform a steam in place (SIP). Autoclaving the whole assembled system requires significant time and the assembly is complicated to transport in and out of the autoclave. If a user chooses to perform a SIP, the filter must be chosen such that it will safely survive the high temperature and pressure for the full length of processing time. Because the embodiments disclosed herein allow the isolation of the SIP conditions from the inside of the capsule, the materials of construction within the core can be chosen differently and from a family that are more appropriate for cost, weight, or fabrication considerations. For example, Opticap® filters are sold in two types. One type is constructed of materials that will survive gamma sterilization but not SIP conditions. The other can survive SIP and autoclave conditions but breaks down during gamma sterilization. In accordance with certain embodiments, the fluid transfer devices can be constructed out of material that survives autoclave, SIP, and gamma sterilization and the inside of the filter is chosen of more economical materials such as polyester, nylon, or other such low cost thermoplastics. During installation and any subsequent steam sterilization process, the device(s) will remain closed, maintaining sterility. After sterilization, the valves can be opened, exposing the inside of the capsule(s) to the process stream. 
     The embodiments disclosed herein also allow for improved integrity testing on the configured filter capsules. Integrity testing commonly involves determining if the test results meet the test specifications. For example, it is common within the industry to perform an air diffusion flow rate test to determine if a filter is integral. If the flow rate is greater than the test specification, the filter is deemed non-integral as the defect is adding an incremental flow. As one skilled in the art of integrity testing can demonstrate that the larger the number of filters that are assembled to a common test port, the greater the error simply due to the larger natural filter manufacturing variation and the thermodynamic effects of a larger housing. The embodiments disclosed herein allow for the isolation of individual filter capsules, thereby improving the integrity testing method. 
     For example, a typical single filter use configuration is shown in  FIG. 8A , and the state of the various transfer devices for integrity testing is shown in the simple configuration of  FIG. 8B , where the integrity test pressure can be connected to the fluid transfer device V- 5 . During testing the other fluid transfer devices remain closed, except for V- 3 . Although this is a preferred arrangement, other configurations can be chosen by the user without rearranging the plumbing or connections to the capsule filter. 
     To perform an integrity testing of multiple filters in either a parallel and serial configuration, shown in  FIGS. 8E and 8F  respectively, the testing pressure is connected to an additional fluid transfer device. This additional fluid transfer device allows the user to retain the original fluid connections while executing a test. A typical filter, such as Opticap® filters from Millipore, do not have isolation valves and require the user to perform the integrity test on all the connected filters together. A small leak will be hidden within the additive flow of all the filters. However, capsule filters with integrated fluid transfer devices allow the user to isolate each filter capsule from another during the test reducing the total gas flow in relation to any background leaks. Of particular note, the embodiments disclosed herein allow the filters to be tested in their processing configuration which will indicate if there are any leaks related to the fluid interconnections. Although a common test method is known as pressure hold using a closed high pressure, other test methods can be employed. For instance, in a parallel configuration similar to that shown in  FIG. 8C , the test pressure is connected to V- 5 A with V- 1 A, V- 2 A, V- 4 B, and V- 3 B being closed. The user may open V- 4 A, V- 1 B, V- 3 A, and V- 2 B whereby the test pressure challenges the interconnection points between the capsules. This allows the user to perform a housing test whereby any change in the test pressure indicates a leak at the interconnection points. 
     The method of integrity testing a set of capsule filters with integrated fluid transfer devices that are configured in a serial flow path, as shown in  8 F, is described here. The test pressure is connected to V- 5 A with V- 4 A and V- 3 A closed and V- 2 A open. As the integrity test proceeds, the flow is measured at the outlet of V- 2 A whereby the integrity of the left filter can be determined. However, as is common with existing filters, the right-hand filter, which is considered downstream, cannot be tested distinctly from the left without measuring flow from V- 2 B. It is notable that the embodiments disclosed herein allow the user new methods to perform an integrity test of both filters in a serial connection without disturbing the sterile fluid pathway that was established at the beginning of processing. For example, in the serial processing configuration of  FIG. 8D , the user&#39;s fluid enters V- 1 A and exits V- 2 B, with the other fluid transfer devices in the states as shown. Although both areas adjacent to these fluid transfer devices need to be sterile, it is advantageous to perform an integrity test of the two filters whereby the sterility downstream of V- 2 B remains integral and undisturbed. Commonly capsule filters without fluid transfer devices require the detachment of the downstream fluid connection to measure actual gas flow. However, the embodiments disclosed herein allow the user to perform an integrity test using actual gas flow by using V- 5 A. In this embodiment, the two filters are arranged serially as in  FIG. 8F  for processing. To test the right-hand filter, the test pressure is attached to V- 5 B with V- 1 B, V- 4 B, V- 2 B, V- 1 A, and V- 2 A, V- 3 A closed (not shown in this configuration). The test gas will flow through the right membrane surface and through the open V- 3 B, V- 4 A and to V- 5 A. The actual gas flow can be measured at V- 5 A. 
     Although these embodiments describe integrity testing using actual gas flow the disclosed embodiments are advantageous to integrity testing that is done by pressure hold. Each capsule filter can be isolated from the others through closing the interconnecting fluid transfer devices.