Abstract:
One embodiment of the invention relates to a liner for a first pump housing in a fluid pump assembly. The fluid pump assembly includes a first pump housing, a second pump housing and a flexible diaphragm disposed between the first and second pump housings. The first pump housing includes a fluid access port for providing fluid communication between an inside housing chamber of the first pump housing and an outside of the first pump housing. The second pump housing is securely mated to the first pump housing. The second pump housing includes a biasing mechanism for selectively displacing a portion of the diaphragm toward the first pump housing. The liner of the invention includes a flexible member removeably secured inside the first pump housing. The liner also includes a first portion of the member being shaped to substantially conform to the interior dimensions of the inside housing chamber and a second portion of the member shaped to substantially conform to the fluid access port. The member forms an inner liner chamber inside the inside housing chamber. The member also includes a mating portion for securing the member to the diaphragm to form a seal there between. The inner liner chamber being in fluid communication with the displaceable portion of the diaphragm. Whereby the displacement of the portion of the diaphragm expels fluid from the inner liner chamber through the fluid access port.

Description:
[0001]    The present application claims priority, in part, to provisional patent Application Ser. No. 60/903,424, filed Feb. 26, 2007. This earlier filed provisional application is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Many fluid handling applications involving biopharmaceutical processes, including filtration, chromatography and mixing, require a pump to move liquid. In critical process applications the pumps are designed to be either easily cleaned and sanitized before and after each use or designed for single use, thus controlling or reducing microbial contamination. However, often these process applications require high quality components that demand precision or that can withstand added wear or high pressures, which makes the parts too valuable to throw away after a single or small number of uses. Also, having to clean and/or sanitize such high quality components can add delays or even increase costs. 
         [0003]    A diaphragm style pump can be used to pump liquid in such critical process applications. In fact, they are used in processes with one pump “head” or with two or more pump “heads” depending on the application. The diaphragm pump cycles between drawing in liquid and expelling liquid from its inner pump chamber. The pump can draw liquid in by different means including gravity (from a pressure head), a vacuum to draw in the diaphragm, and/or by a piston type of mechanism. The pump can expel liquid by different means including a piston or air pressure. However, as with the critical process applications described above, diaphragm pumps are still required to be cleaned and/or sanitized between uses. 
         [0004]    It is therefore desirable to provide an apparatus and method for use with a diaphragm pump for critical process applications that overcomes the shortcomings found in the prior art. In particular, an apparatus and method that allows such diaphragm assemblies to be easily cleaned, sterilized or uncontaminated between uses. 
       SUMMARY OF THE INVENTION 
       [0005]    One embodiment of the invention relates to a liner for a first pump housing in a fluid pump assembly. The fluid pump assembly includes a first pump housing, a second pump housing and a flexible diaphragm disposed between the first and second pump housings. The first pump housing includes a fluid access port for providing fluid communication between an inside housing chamber of the first pump housing and an outside of the first pump housing. The second pump housing is securely mated to the first pump housing. The second pump housing includes a biasing mechanism for selectively displacing a portion of the diaphragm toward the first pump housing. The liner of the invention includes a flexible member removeably secured inside the first pump housing. The liner also includes a first portion of the member being shaped to substantially conform to the interior dimensions of the inside housing chamber and a second portion of the member shaped to substantially conform to the fluid access port. The member forms an inner liner chamber inside the inside housing chamber. The member also includes a mating portion for securing the member to the diaphragm to form a seal there between. The inner liner chamber being in fluid communication with the displaceable portion of the diaphragm, whereby the displacement of the portion of the diaphragm expels fluid from the inner liner chamber through the fluid access port. 
         [0006]    Additionally, the liner member can be formed from a single unitary material. Also, the member can include a radially protruding housing flange secured between the first and second pump housings. Further, the member can include a nozzle flange radially extending from the second portion. The nozzle flange can be collapsible for insertion through the fluid access port. The second portion of the member can extend outwardly away from the first pump housing. The second portion can be flexible enough to fold over an outer portion of the fluid access port. The member and the flexible diaphragm can be permanently secured at the mating portion. Also, the member can be secured to the diaphragm by at least one of an adhesive and bonding agent. The flexible diaphragm can be integrally formed with the member and extending from the mating portion. The first pump housing can be removeably secured to the member. Also, the first pump housing can be formed by at least two removeably secured housing segments. Further, the first pump housing can include a sealing element disposed in a mating region between the housing segments. 
         [0007]    Another embodiment of the invention relates to a fluid pump assembly including a first pump housing, a second pump housing, a flexible diaphragm and a flexible liner. The first pump housing includes a first inner chamber and a fluid access port for providing fluid communication between an outside of the first pump housing and the first inner chamber. The second pump housing is removeably secured to the first pump housing. The flexible diaphragm is disposed between the first and second pump housings. Also, a portion of the diaphragm is selectively displaceable toward the first pump housing. Further, the flexible liner is removeably secured substantially inside the first pump housing. The liner is shaped to substantially conform to the interior dimensions of the first inner chamber and the fluid access port. Also, the liner forms an inner liner chamber inside the first inner chamber, wherein displacement of the diaphragm toward the first pump housing expels fluid from the inner liner chamber. 
         [0008]    Additionally, the liner can be formed from a single unitary material. Also, the liner can include a radially protruding housing flange secured between the first and second pump housings. Further, the liner can includes a nozzle flange radially protruding from the liner for engaging an outer portion of the fluid access port. The nozzle flange can be collapsible for insertion through the fluid access port. Also, the nozzle flange can be flexible enough to fold over an outer portion of the fluid access port. The liner can be secured to the diaphragm forming a seal there between. Also, the liner can be secured to the diaphragm by at least one of an adhesive and bonding agent. Further, the liner can be integrally formed with the diaphragm. The first pump housing can be formed by at least two removeably secured housing segments. Also, the first pump housing can include a sealing element disposed in a mating region between the housing segments. 
         [0009]    These and other embodiments, features, and advantages of this invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a cross-sectional view of a liner in a diaphragm pump assembly in accordance with an embodiment of the subject invention. 
           [0011]      FIG. 2  is a perspective view of a diaphragm pump liner in accordance with an embodiment of the subject invention. 
           [0012]      FIGS. 3   a - 3   b  are cross-sectional views of a diaphragm pump liner with an installation member mounted thereon and removed therefrom, respectively, in accordance with an embodiment of the subject invention. 
           [0013]      FIG. 4  is a perspective view of a split upper pump housing half, in accordance with an embodiment of the subject invention. 
           [0014]      FIG. 5  is a cross-sectional view of an alternative upper pump housing and liner with two fluid ports, in accordance with another embodiment of the subject invention. 
           [0015]      FIG. 6  is a cross-sectional view of another alternative upper pump housing and liner with two fluid ports, in accordance with yet another embodiment of the subject invention. 
           [0016]      FIGS. 7   a  and  7   b  are cross-sectional views of an alternative upper pump housing and liner, in accordance with yet another embodiment of the subject invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    In accordance with an embodiment of the subject invention, a liner is provided inside an upper diaphragm pump housing, which can be easily removed and disposed of when needed so that the main pump parts can be re-used without the need to clean, sanitize and/or decontaminate them. Also, providing a liner can be more economical than disposing of single use pump parts. Further, a liner facilitates the use of more permanent and durable outer pump parts that are protected from wear or degradation by the liner. 
         [0018]    With reference to the drawings,  FIG. 1  shows a fluid diaphragm pump assembly  10  for coupling to a process application  5 . The pump assembly  10  includes an upper pump housing  100 , a lower pump housing  120 , a flexible diaphragm  150  and a removable flexible liner  200  (the liner  200  is drawn as a solid line covering the upper, inside and lower surfaces of the upper pump housing  100 ). 
         [0019]    In a preferred embodiment, shown in  FIG. 1 , the liner  200  covers the upper, inside and lower surfaces (referred to as the working surfaces) of the upper pump housing  100 . The upper housing  100  preferably includes a cylindrical main portion  110  and a nozzle  105  for in taking and expelling fluid. The upper housing  100  is secured to a lower pump housing  120  preferably by clamping together flanges  115 ,  125 . Contemporary clamping techniques can be used, such as a sanitary clamp, tri-clamp or a locking collar (not shown). The lower pump housing  120  guides and supports a biasing mechanism  160 . In the embodiment shown, biasing mechanism  160  includes a piston assembly for moving the diaphragm  150 , with piston stem  165  passing through an aperture  145  in a lower portion  140  of the lower pump housing  120 . However, the biasing mechanisms  160  can alternatively include a fluid pressure source, which applies a pressure force to bias the diaphragm  150  accordingly. While the lower portion  140  can be integrally formed with the lower pump housing  120 , it can also be two separate elements joined together as shown. Also, the lower pump housing  120  and/or lower portion  140  can include one or more vacuum and/or air ports  147 . 
         [0020]    The flexible diaphragm  150  includes an upper flange that is secured between the upper and lower housing flanges  115 ,  125 . The flexible diaphragm retains fluid in the diaphragm pump compartment. The flexible diaphragm  150  allows the pump to intake and expels fluid, yet acts as a barrier preventing such fluid from crossing through or past the diaphragm  150  between the upper and lower housings  100 ,  120 . Preferably, the diaphragm  150  is a durable, flexible material such as silicone or a thermoplastic elastomer. It may even have a fabric component within the flexible material to provide additional strength. Different methods, such as a clamp, can be used to secure the upper and lower pump housings  100 ,  120  together, which in turn secure the diaphragm  150  in place. A more detailed disclosure of similar diaphragm pump, but without a liner  200 , is provided in a co-pending patent application, Ser. No. 11/920,413, entitled “Sanitary Diaphragm Pump for Critical Bioprocess Applications,” commonly assigned to PendoTECH, which is incorporated herein by reference. 
         [0021]    The fluid diaphragm pump assembly  10  thereby forms a fluid chamber  250  between an upper surface of the diaphragm  150  and the inner surfaces of the liner  200 . In this way, the liner  200  and the diaphragm  140  are the only elements of the diaphragm pump assembly  10  that come in contact with the fluid. In contrast, the chamber inside the lower pump housing  120  and below the diaphragm  150  does not ever come in contact with the critical process mixing fluids that enter chamber  250 . Thus, when the diaphragm pump assembly  10  cycles between drawing-in and expelling fluid from chamber  250 , at least a portion of the diaphragm  150  is adapted to extend back and forth between the inside of the upper and lower housings  100 ,  120 . Preferably, substantially the entire diaphragm  150 , less the secured upper flanges, can be forced to deflect toward and/or away from the nozzle  105 . 
         [0022]    As shown in  FIG. 2 , the liner  200  preferably includes a main cylindrical portion  215 , a lower coupling flange  210  and a nozzle insert portion  205 . Preferably, the lower coupling flange  210  of the liner  200  is sealed between the upper pump housing  100  and the diaphragm  150 . In turn, the diaphragm  150  is sealed between the lower pump housing  120  and the liner  200 . The liner  200  continuously covers all inner surfaces from the connection to the process  5  to the diaphragm  150 . Preferably, the liner  200  is shaped to substantially conform to the interior shape and dimensions of the upper pump housing  100 . In this way, upon installation, the outer surfaces of the liner  200  directly engage substantially all inner surfaces of the upper pump housing  100 . A tight match between the upper housing  100  and the liner  200  can minimize air or fluids getting between the liner and the internal surface of the upper housing  100 . The tight match can help resist relative movement between the liner  200  and the upper housing  100 , as the pump  10  cycles between drawing and expelling fluid. Also, the fact that the lower coupling flange  210  is secured to and sealed with the upper housing  100  also prevents air or fluids from getting behind the liner  200 , for further resisting relative movement between the two elements  100 ,  200 . 
         [0023]    Preferably, the liner is made of a material the can be formed in the required shape and installed into the pump and the process. It can be made as a single unitary piece or made from more than one molded, machined, stamped or extruded pieces that are secured together to make one contiguous liner  200  in the required shape. The liner is preferably made of inexpensive material(s) designed for single or limited use, such as those discussed in AAMI TIR17: 1997. 
         [0024]    In order to install the liner  200 , preferably the nozzle insert portion  205  is passed through the upper housing nozzle  105 . Once passed through, preferably the liner flange  220 , can radially extend from the insert portion  205  and be clamped between the nozzle  105  and a connection to the process  5 . Thus, the flange  220  acts as an integrally formed gasket to create a seal between the upper housing nozzle  105  and the adjoining process connection  5 . Once the flange  220  is secured, it can further help resist relative movement between the liner  200  and the upper housing  100 , as the pump  10  cycles between drawing and expelling fluid. Further, this will prevent air or fluids from getting between the liner  200  and the upper housing  100 . 
         [0025]      FIG. 3   a  and  3   b  show an alternative installation technique, which uses a constrictor  300  to collapse and/or narrow the upper liner flange  220 .  FIG. 3   a  shows the constrictor applied to the liner  200 . In this embodiment the constrictor  300  is in the form of a removable cap, however tape or other radially constricting methods can be used. Preferably, the constrictor  300 , once applied to the flange  220 , should be able to easily pass through the inside of nozzle  105 . Once the liner  200  is fully seated in the upper housing  100 , the constrictor  300  can be pulled away in direction A or otherwise removed, allowing the flange  220  to return to its original shape, as shown in  FIG. 3   b.    
         [0026]      FIG. 4  shows an alternative embodiment for the upper pump housing  101  that is well suited to simplify and expedite installation of the subject liner  200 . In particular, an upper housing, similar to upper housing  100  is split vertically (as shown in the orientation of  FIG. 4 ). In this way, the upper pump housing  101  is formed from two or more separable portions or housing segments. A sealing element  109  can be provided along the mating surfaces of the separable housing portions  101 , in order to prevent air or fluids from getting inside the housing  101  and behind the liner  200 . The embodiment in  FIG. 4 , shows one of two equal halves of the upper pump housing  101  that when combined form a complete upper housing  101  similar to that discussed above. It should be understood, however, that the two or more housing portions need not be symmetrical to one another or equal in size. The upper flange  220  of the liner can be more easily installed in a split-housing  101 , without the need for a constrictor  300 . The liner  200  can be inserted into one portion of the split-housing  101  and then the other portion(s) would be mounted thereon to encase the liner  200 . Preferably, the split upper pump housing  101  includes a seal between the vertical seams of the separate portions in order to prevent air from getting inside the combined upper housing portions  101 . The seal  109  can be in the form of a separate gasket. However, alternatively the liner  200  can be provided with one or more flanges that extend vertically from the outside of liner  200 . Thus, the added vertical flanges can serve to seal the seam between the upper housing portions  101 . Further, as an alternative, the split-housing  101  can be provided with mating dowels  112  and recesses  113  for aligning the separate portions. 
         [0027]      FIGS. 5 and 6  show further alternative embodiments with the liners  201 ,  202  matching upper housings  102 ,  103  which each have more than one fluid port and thereby more than one connection to the process  5 . This type of configuration allows for different flow paths, such as fluid flowing in through one port and out through the other.  FIG. 5  shows a duel nozzle configuration with the nozzles  106   a,    106   b  angled away from each other. Accordingly, the liner  201  includes nozzle liners  221   a,    221   b  in a matching angled configuration. In contrast,  FIG. 6 , while including two nozzles  107   a,    107   b  has them extending directly away from the lower portions. However, as with  FIG. 5 , the liner  202  includes nozzle liners  222   a,    222   b  that match the configuration of nozzles  107   a,    107   b.  It should be understood that additional nozzles and nozzle liners can be provided to suit the application. Also, the nozzles can be configured to extend from a more central portion of the upper housings  100 ,  101 ,  102 ,  103 . 
         [0028]      FIGS. 7   a  and  7   b  show a further alternative embodiment of the liner  203  suited for upper housing  104 . The upper nozzle  108  of the housing  104  includes a hose barb fitting. Thus, the liner  203  is not provided with a nozzle flange per se, but rather is provided with a nozzle insert portion  223  that extends well beyond the upper portion of the hose barb fitting, as shown in  FIG. 7   a.  By using a particularly flexible and/or thin material for the liner  203 , the upper extent of the insert portion  223  can be folded back onto the hose barb fitting, as shown in  FIG. 7   b.  Thus, allowing the liner  203  and upper housing  104  to be secured together when the hose barb is inserted in the adjoining process (not shown). For example, process tubing can be fitted over the hose barb and thus secured in place. Alternatively, the process could have a male hose barb adapted to be inserted inside the insert portion  223 , just inside the nozzle  108 . 
         [0029]    It should be understood, that while particular examples of process connections have been described and illustrated herein, the subject invention should not be limited to use with those examples. Preferably, the liner and pump assembly as disclosed herein can be attached or coupled to virtually any process application that can use a diaphragm pump. 
         [0030]    The diaphragm  150  and liner  200  can be held together by virtue of being sandwiched between the two housing flanges  115 ,  125  and held by an external clamp. A good seal between these two elements  150 ,  200  can prevent air from getting behind the liner. Alternatively, these disposable members  150 ,  200  can be directly bonded or sealed together with a bonding agent or adhesive applied to mating surfaces of one or both members  150 ,  200 . Such bonding agents or adhesive can be applied during installation. Alternatively, the agents or adhesives can be applied before installation, but activated just prior to installation, such as through the application of moisture or by providing a peel-away strip. By bonding or fixedly securing the two members  150 ,  200 , the pump can be more easily disassembled after use without spilling any residual process fluids from inside the liner chamber  250 . Ultimately, the permanently secured diaphragm  150  and liner can be removed after use, along with additional upstream secured process elements that are similarly contaminated during use. Such a “closed system” leaves the pump housing  100  and other assembly parts uncontaminated and available for quick reuse. As yet a further alternative, the diaphragm  150  and liner  200  can be formed together as a single continuous unitary member. 
         [0031]    In a preferred embodiment, the liner  200 , along with the diaphragm  150  are designed as disposable units for single or very limited use. Preferably, only two elements (the liner  200  and the diaphragm  150 ) ever come in contact with the process fluid. Thus, by providing an easily removable liner  200 , together with the diaphragm  150 , the contaminated parts can be changed-out and disposed of after a single use. This prevents having to disassemble the entire pump, with the associated potential human or environmental exposure to process constituents, which in some cases may be hazardous. It should be noted that references herein to the term “disposable” are to elements that are designed to be thrown away or discarded after a very limited number of uses and preferably a single use. Even further, before use, the liner  200  along with the diaphragm  150  can be pre-sterilized (by gamma, chemical or moist heat processing) ready for use without the need to clean or sterilize before assembly. 
         [0032]    As will be recognized by one of skill in the art, many variations are possible and within the scope of this invention. For example, the pump assembly  10  can be made to any convenient size, from relatively small bench top type systems to large, industrial scale pumping systems. Also, it should be understood that the proportional characteristics of the inner chambers versus the fluid ports can be increased or decreased to suit a desired application. 
         [0033]    It should be noted that the fluid can be a homogenous liquid, a composition of disparate fluids or one or more fluids combined with other solid matter. As mentioned above, the fluid is preferably drawn from one or more process lines  5  into the fluid chamber  250  and then expelled through liner port  230 . 
         [0034]    While various embodiments of the present invention are specifically illustrated and/or described herein, it will be appreciated that modifications and variations of the present invention may be effected by those skilled in the art without departing from the spirit and intended scope of the invention.