Patent Publication Number: US-11639713-B2

Title: Mechanically driven modular diaphragm pump

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation application of U.S. application Ser. No. 16/099,128, filed Nov. 5, 2018, which in turn is a National Stage Application of PCT/US2017/031363 filed May 5, 2017, which in turn claims the benefit of each of U.S. Provisional Application No. 62/332,558 filed May 6, 2016, U.S. Provisional Application No. 62/339,223 filed May 20, 2016, U.S. Provisional Application No. 62/343,548 filed May 31, 2016, and U.S. Provisional Application No. 62/399,713 filed Sep. 26, 2016, the disclosures of which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     Diaphragm pumps can be useful for pumping fluids and gasses, particularly where versatility and contamination control are of concern and/or to move otherwise difficult to pump fluids. Many conventional diaphragm pumps are large and intended for permanent installation. Moreover, many conventional diaphragm pumps are not easily reconfigurable or serviceable, which can be particularly troublesome when using a diaphragm pump at a remote jobsite. Smaller diaphragm pump are easier to transport and handle, but have inherent output and flow limitations. These limitations can restrict the number of practical applications for diaphragm pumps. There is a continuing need for diaphragm pumps which are portable, reconfigurable, and serviceable while maintaining high performance. 
     SUMMARY 
     Several embodiments demonstrating modular mechanically driven diaphragm pump features are presented herein. A first embodiment includes a motor and a drive mechanism, the drive mechanism configured to convert rotational motion output from the motor into linear reciprocal motion. The first embodiment further includes a diaphragm pump comprising a diaphragm, a drive rod, and a housing, the diaphragm located within the housing, the drive rod connected to the diaphragm such that the diaphragm is moved by the drive rod. The first embodiment further comprises a coupling that mounts the diaphragm pump to the drive mechanism, the coupling forming a static connection that fixes the housing with respect to the frame and a dynamic connection that attaches the drive rod to the drive mechanism such that the drive mechanism can move the diaphragm relative to the housing by moving the drive rod, wherein the coupling is configured to dismount the diaphragm pump from the drive mechanism by disengaging the static connection and the dynamic connection. 
     A second embodiment of a modular diaphragm pump comprises a motor and a drive mechanism, the drive mechanism configured to convert rotational motion output from the motor into linear reciprocal motion. The second embodiment further comprises a diaphragm pump comprising a diaphragm, a drive rod, and a housing, the diaphragm located within the housing, the drive rod configured to be reciprocated by the drive mechanism to move the diaphragm. In the second embodiment, the housing and the diaphragm form a first chamber and a second chamber, the first chamber is formed in part by a first side of the diaphragm and the second chamber is formed in part by a second side of the diaphragm, the diaphragm is configured to be moved via the drive rod to expand and contract the volumes of the first chamber to pump fluid through the first chamber, and the second chamber is configured to hold a gas under pressure such that the gas applies pressure on the second side of the diaphragm to increase the pumping force generated by the diaphragm pump. 
     A third embodiment of a modular diaphragm pump comprises a motor and a drive mechanism, the drive mechanism configured to convert rotational motion output from the motor into linear reciprocal motion. The third embodiment further comprises a diaphragm pump comprising a diaphragm, a drive rod, and a housing, the diaphragm located within the housing, the drive rod connected to the diaphragm such that the diaphragm moves with the drive rod to pump a fluid. The third embodiment further comprises a dampener mounted to the housing, the dampener comprising a second diaphragm that contacts the pumped fluid and moves to reduce downstream flow pulsation due to upstream flow pulsation created by movement of the diaphragm in pumping the fluid. 
     The scope of this disclosure is not limited to this summary. Further inventive aspects are presented in the drawings and elsewhere in this specification and in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an isometric view of a modular diaphragm pump system. 
         FIG.  2    is an isometric view of the modular diaphragm pump system of  FIG.  1    with the modular diaphragm pump removed. 
         FIGS.  3 - 4    are detailed views showing the decoupling of the modular diaphragm pump from the rest of the modular diaphragm pump system of  FIG.  1   . 
         FIG.  5    is a sectional view of part of the modular diaphragm pump system of  FIG.  1   . 
         FIG.  6    is an isometric view of a modular diaphragm pump system having an integrated dampener. 
         FIG.  7    is a cross sectional view of the modular diaphragm pump of  FIG.  6    having the integrated dampener. 
     
    
    
     This disclosure makes use of multiple embodiments and examples to demonstrate various inventive aspects. The presentation of the featured embodiments and examples should be understood as demonstrating a number of open-ended combinable options and not restricted embodiments. Changes can be made in form and detail to the various embodiments and features without departing from the spirit and scope of the invention. 
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure are used to pump fluids. Various types of fluids can be pumped, including fluids containing solid matter. Each pump actuates at least one diaphragm in an interior space of a pump housing to increase and decrease the size of a chamber formed by the diaphragm and housing. Check valves are used to control the flow of fluid into and out of the chamber so that the diaphragm pump productively moves the fluid from an inlet to an outlet. A motor and a drive mechanism are used to move the diaphragm, such as via a drive rod. There are various different types of drive motors as well as various different types of diaphragm pumps. Different types of drive motors and/or diaphragm pumps can be available to users and can be easily combined and swapped onsite to suit the particular and changing needs of the user. For example, one type of diaphragm pump may have a diaphragm sized for high pressure while another type of diaphragm pump may have a diaphragm sized for high flow. As another example, different materials used to construct different diaphragm pumps may have different chemical resistances and thus different suitabilities for different pumping tasks in a particular project. Additionally or alternatively, a diaphragm pump may wear and need replacement or may be in need of servicing onsite. Aspects of diaphragm pump modularity are disclosed herein to address these and/or other needs. 
       FIG.  1    is a perspective view of a modular diaphragm pump system  2 . The modular diaphragm pump system  2  includes reciprocating power unit  16  onto which a diaphragm pump  6  is mounted. The reciprocating power unit  16  provides reciprocating motion to operate the diaphragm pump  6 . The reciprocating power unit  16  includes a motor  4 . While an electric rotary drive motor (e.g., a conventional brushless direct current rotor stator motor) is shown herein, the motor  4  can be any type of electric, combustion (e.g., gas or diesel), pneumatic, or hydraulic motor. The motor  4  outputs rotational motion. As shown further herein, the reciprocating power unit  16  includes a drive mechanism to convert the rotational motion output by the motor  4  to linear reciprocating motion. 
     The reciprocating power unit  16  includes a structural frame  8 . The structural frame  8  can include vertically and/or horizontally orientated metal tubes. The structural frame  8  is portable and not attached or anchored to a larger structure. Wheels  14  are attached to the structural frame  8  for wheeling the fluid pumping system  2  around for portability. The motor  4  and drive mechanism are mounted on the structural frame  8 . 
     A diaphragm pump  6  is mounted to the reciprocating power unit  16  by a pump coupling  10 . A portion of the coupling  10  is located behind door  38 . As further shown herein, the door  38  can be opened to mount and dismount the diaphragm pump  6  from the reciprocating power unit  16 . The diaphragm pump  6  is secured to the reciprocating power unit  16 , at least in part, by clamp  34 . The clamp  34  is part of the coupling  10 . The clamp  34  wraps around the diaphragm pump  6  to fix the diaphragm pump  6  to the reciprocating power unit  16 . The diaphragm pump  6  may only be attached to the reciprocating power unit  16  via the pump coupling  10 . In this way, the diaphragm pump  6  may not be attached directly or indirectly to the structural frame  8  or other part of the reciprocating power unit  16  except via the pump coupling  10 . This single area of attachment between the diaphragm pump  6  and the reciprocating power unit  16  facilitates modular removal and replacement of the diaphragm pump  6  from the fluid pumping system  2  as further discussed herein. 
     The diaphragm pump  6  includes a pump housing formed by a first pump cover  22  and a second pump cover  24 . The pump covers  22 ,  24  may be threaded, bolted, welded, adhered, or otherwise rigidly attached to each other to form the pump housing. The pump covers  22 ,  24  can be formed from metal (e.g., stainless steel) or polymer (e.g., polytetrafluoroethylene). The diaphragm pump  6  includes an inlet port  20  through which fluid being pumped (i.e. working fluid) is moved into the diaphragm pump  6 . The diaphragm pump  6  includes an outlet port  18  through which the fluid is expelled from the diaphragm pump  6 . Pipes, tubes, manifolds, connectors, and the like, which are not illustrated but are known in the art, can be connected to the outlet port  18  and the inlet port  20  to manage fluid flow. 
       FIG.  2    is a perspective view of the fluid pumping system  2  similar to that of  FIG.  1    except that in  FIG.  2    the diaphragm pump  6  has been dismounted from the reciprocating power unit  16 . As shown, the diaphragm pump  6  includes a pump neck  26 . The pump neck  26  is shown as a cylindrical element, however the pump neck  26  can take different shapes. The pump neck  26  projects upwards from the first pump cover  22 . The pump neck  26  can be directly attached, or integral and continuous with, the first pump cover  22 . The pump neck  26  can indirectly attach to the second pump cover  24 . The first pump cover  22  can be directly attached to the second pump cover  24  although an intermediary housing structure may be placed between the pump covers  22 ,  24 . The diaphragm pump  6  further includes a drive rod  28 . The drive rod  28  protrudes out from the pump neck  26 . The drive rod  28  can be formed from metal. As further shown herein, the drive rod  28  is reciprocated by the drive mechanism of the reciprocating power unit  16  relative to the pump neck  26  and the pump covers  22 ,  24 . The pump neck  26  can be part of the pump housing, together with the pump covers  22 ,  24 , of the diaphragm pump  6 . The drive rod  28  includes a head  30  which attaches to a collar  36  of the pump coupling  10 . 
     To dismount the diaphragm pump  6 , the door  38  is opened to further expose the pump coupling  10 . The pump coupling  10  includes a pump mount frame  32 . The pump mount frame  32  is formed from metal and is rigidly fixed, directly or indirectly, to the structural frame  8  of the reciprocating power unit  16 . The pump mount frame  32  structurally supports the diaphragm pump  6  when the diaphragm pump  6  is attached to the pump coupling  10 . The pump mount frame  32  includes a receiver  40 . The receiver  40  is a recessed space within the pump mount frame  32  into which part of the diaphragm pump  6  is placed and secured when the diaphragm pump  6  is mounted on the pump coupling  10 . For example, the pump neck  26  and drive rod  28  can be received in the receiver  40  when then diaphragm pump  6  is mounted on the pump coupling  10 . A nut  12  is located around the pump neck  26 . A portion of the pump neck  26  can be threaded to engage with inner threading on the nut  12  and allow the nut  12  to move up and down the pump neck  26  by relative rotation between the nut  12  and the pump neck  26 . 
     When the diaphragm pump  6  is mounted, the nut  12  can then be tightened against the bottom of the pump mount frame  32  to clamp and secure the pump neck  26 , and the rest of the diaphragm pump  6 , to the pump mount frame  32 . To allow the diaphragm pump  6  to be dismounted, the nut  12  can be rotated to move the nut  12  down the pump neck  26  and away from the bottom of the pump mount frame  32  to relieve the clamping force on the pump mount frame  32 . The nut  12  engaging with the pump mount frame  32  is one of several mechanisms that can be additionally or alternatively employed to secure the diaphragm pump  6  to the reciprocating power unit  16 . For example, the pump coupling  10  in the illustrated embodiment is shown to include the clamp  34 . The clamp  34  is shown in an open position in  FIG.  2   , allowing the pump neck  26  to be removed from the receiver  40  and the diaphragm pump  6  to be dismounted from the reciprocating power unit  16 . The clamp  34  can fix the diaphragm pump  6  to the pump mount frame  32 . 
       FIGS.  3 - 4    show detailed views of the pump coupling  10  of the previous Figs. In particular, the progression of  FIGS.  3 - 4    shows the dismounting of the diaphragm pump  6  via the pump coupling  10 .  FIG.  3    shows the diaphragm pump  6  in a mounted state. The door  38  is opened to expose the receiver  40  and the clamp  34  is likewise open to allow removal of the diaphragm pump  6 . As shown, the door  38  is mounted on a guard. Collar  36  is part of the coupling  10 . As shown in  FIG.  3   , the collar  36  includes a slot  42 . The slot  42  accepts the head  30  of the drive rod  28 . Mechanical elements, other than a collar  36  and head  30 , can connect to the drive rod  28  to the drive mechanism for reciprocating the drive rod  28 . For example, a metal pin that extends through aligned holes in the collar  36  and the drive rod  28  can couple the collar  36  and the drive rod  28 , wherein the holes extend transverse to the long axes of the collar  36  and the drive rod  28 . 
       FIGS.  3 - 4    show that the pump neck  26  can include a rib  44  or other peripheral protrusion. The rib  44  extends entirely around the pump neck  26 . The rib  44  is annular. The rib  44  fits into a groove  46  of the coupling  10 . In this case, the rib  44  fits into a groove of the clamp  34 , and into a groove  46  formed in the pump mount frame  32 , to index the position of the pump neck  26  and prevent movement of the pump neck  26  (forming part of the pump housing) relative to the drive rod  36  when the drive rod  36  is moved. The locations of the rib  44  and groove  46  can be reversed. In some alternative designs of the pump coupling  10 , a shelf of the pump mount frame  32  could be located within the receiver  40 , such as forming the bottom of the receiver  40 . The rib  44  or other peripheral protrusion can be placed on top of the shelf while the nut  12  is tightened against the bottom of the shelf to clamp the shelf between the nut  12  and the rib  44  or other peripheral protrusion to secure the diaphragm pump  6 . In such an alternative design, the particular clamp  34  and/or groove  46  may not be included. Other designs for the pump coupling  10  are possible. In other alternative designs, the pump mount frame  32  includes one or more projections (e.g., pins) which are received by one or more apertures formed in the pump neck  26  or other part of the diaphragm pump  6 . 
     The interface between the rib  44  or other peripheral protrusion and the groove  46  or other part of the pump mount frame  32 , the interface between nut  12  and the bottom of the pump mount frame  32 , the locking of the clamp  34  on the pump neck  26 , and/or the reception of the pump neck  26  in the receiver  40  forms a static connection. The static connection fixes the pump neck  26 , as well as the rest of the housing of the diaphragm pump  6  (e.g., the covers  22 ,  24 ) to the pump mount frame  32 . When the static connection is made, the pump neck  26 , as well as the rest of the housing of the diaphragm pump  6  (e.g., the covers  22 ,  24 ), will not move relative to the pump mount frame  32 , the structural frame  18 , and other non-moving parts of the reciprocating power unit  16  despite the collar  42  of the reciprocating power unit  16  moving the drive rod  28  of the diaphragm pump  6 . The interface of the drive rod  28  with the collar  36  forms a dynamic connection whereby the drive rod  28  and the collar  36  move together. As demonstrated in  FIGS.  3 - 4   , a sliding motion removes the pump neck  26  from the recess  40  (and the rib  44  out of the groove  46 ) and also removes the head  30  of the piston  28  from the slot  42  of the collar  36 . This single sliding motion simultaneously disengages both the static and dynamic connections, assuming any clamps are loosened. It is noted that before the sliding motion to dismount the diaphragm pump  6 , the clamp  34  and nut  12  were loosened. Dismounting of the diaphragm pump  6  allows the diaphragm pump  6  to be cleaned and serviced. Alternatively, the diaphragm pump  6  can be removed in this manner for replacement by a newer, cleaner, or alternatively configured diaphragm pump  6  (e.g., a larger, smaller, or adapted for different fluids, pressures, viscosities, and/or chemical resistances). In either case, diaphragm pump  6  or a different diaphragm pump can be remounted by essentially a similar, but opposite, sliding motion and then tightening of any clamps. The diaphragm pump  6  is slid in a single linear motion to simultaneously engage (or reengage) the static and dynamic connections. 
       FIG.  5    is a sectional view showing the diaphragm pump  6 , pump coupling  10 , drive mechanism, and motor  4  of the fluid pumping system  2 . The motor  4  outputs rotational motion (e.g., via a pinion) which is converted by the drive mechanism into linear reciprocal motion. The drive mechanism includes eccentric  48  and connecting arm  50  connected as a crank mechanism. The top of the connecting arm  50  is connected to the eccentric  48  while the bottom of the connecting arm  50  is attached to the collar  36 . Rotation of the eccentric  48  by the motor  4  moves the bottom of the connecting arm  50  in a linear reciprocating manner. As an alternative drive mechanism, a scotch yoke could convert rotation motion of the eccentric  48  into liner reciprocating motion of the collar  36 . The collar  36  is restrained in a guide of the pump mount frame  32  to only slide in a linear manner, such as only up and down. The head  30  of the drive rod  28  is cradled in the slot  42  of the collar  36 . The head  30 , and the rest of the drive rod  28 , moves up and down with the movement of the collar  36 . 
     The diaphragm pump  6  includes a diaphragm  54  sandwiched between the first and second pump covers  22 ,  24 . The middle of the diaphragm  54  is allowed to move while the rim  56  of the diaphragm  54  is pinched and secured between the first and second pump covers  22 ,  24 . The diaphragm  54  can be formed from rubber or other flexible and resilient material. The first and second pump covers  22 ,  24  define a space which is divided by the diaphragm  54  to include a first chamber  52  and a second chamber  66 . The first chamber  52  is a working fluid chamber in that fluid being pumped is moved through the first chamber  52  by movement of the diaphragm  54 . Fluid from the inlet port  20  is drawn into the first chamber  52  when the diaphragm  54  moves upwards. More specifically, on the upstroke of the diaphragm  54 , fluid is sucked through the first check valve  62  as the volume of the first chamber  52  increases due to the upward movement of the diaphragm  54 . Fluid is forced out of the first chamber  52  through second valve  60  when the diaphragm  54  moves downwards. More specifically, on the downstroke of the diaphragm  54 , fluid is forced from first chamber  52  as the volume of the first chamber  52  decreases due to the downward movement of the diaphragm  54 . The orientations of the first and second check valves  62 ,  60  manage the direction of fluid flow in an upstream-to-downstream direction (i.e. from inlet port  20  to outlet port  18 ) by preventing retrograde downstream-to-upstream flow. The first and second check valves  62 ,  60  are shown as each comprising a ball, a seat, and a spring, however other check valve designs can be substituted. Due to the direction of flow of fluid managed by the first and second check valves  62 ,  60 , these valves can be inlet and outlet check valves, respectively. The first and second check valves  62 ,  60  as well as the inlet and outlet ports  20 ,  18  are integrated into the housing of the diaphragm pump  6 . 
     The drive rod  28  is attached to the diaphragm  54  (directly or indirectly) by a connector  58 . The connector  58  moves with the drive rod  28 . In the illustrated embodiment, the connector  58  comprises two plates  64 A-B which sandwich a portion of the diaphragm  54 . The diaphragm  54  may be connected with the drive rod  28  in other ways. The middle of the diaphragm  54  moves up and down with the drive rod  28 . The spacing between the drive rod  28  and the connector  58  can be adjusted. Changing the separation distance allows the depth of movement of the diaphragm  54  in the first chamber  52  to be adjusted. A spacer  70  can be embedded or otherwise fixed to one or both of the plates  64 A-B. Spacer  70  can be threadedly received within the bottom of the drive rod  28  such that rotation of the drive rod  28  relative to the spacer  70  increases or decreases the separation between the drive rod  28  and the diaphragm  54 . Other spacing adjustment mechanisms can be substituted. 
     The diaphragm pump  6  is shown to include a channel  74  through the pump housing. More specifically, the channel  74  is formed through the first cover  22 . The channel  74  allows air to move in and out of the second chamber  66 . The channel  74  may be open in some configurations to freely let air into, and out of, the second chamber  66  during pumping. In some configurations, a valve  72  in the channel  74  prevents the flow of air through the channel  74 , or at least in one direction. Specifically, the valve  72  can be check valve (e.g., ball, seat, and spring) that lets air into the second chamber  66  but prevents air in the second chamber  66  from escaping outside. The valve  72  may be a plug fit into the channel  74  (e.g., threadedly engaged with the channel  74 ). In some embodiments, pressurized gas is kept within the second chamber  66  during pumping by the valve  72 , as further discussed herein. 
     Just considering the mechanical force (and not pneumatic force) developed by the motion of the diaphragm  54 , the change in pressure of the working fluid in the first chamber  52  during the down stroke is determined by the mechanical force pushing on the diaphragm  54  by the drive mechanism (via the drive rod  28 ) and the effective surface area of the diaphragm  54 . For example, 1000 pounds of force pushing on the diaphragm  54  with a surface area of 10 square inches would generate a fluid pressure change of 100 PSI (1000 pounds/10 square inches). To create higher fluid pressures, the motor  4  may require higher horse power or a different drive mechanism. Even if these aspects are changed, they may only be partially utilized because the upstroke (i.e. the suction stroke) requires much lower motor  4  horse power and drive forces. Instead of increasing the power of the motor  4  or changing the drive mechanism, a gas charge can be provided in the second chamber  66  to increase the power of the downstroke, as further discussed herein. 
     The second chamber  66  can contain pressurized gas. The pressurized gas maintained within the second chamber  66  can be any gas, such as pressurized ambient air. The pressurized gas is supplied through the channel  74  and kept within the second chamber  66  by valve  72 . Assuming no intentional or unintentional loss of the gas over repeated reciprocation cycles, the pressurized gas is maintained on the non-working fluid side of the diaphragm  54  and in particular within the second chamber  66 . The gas expands on a downstroke of the diaphragm  54  to increase pumping stroke force through the diaphragm  54 , and the gas is recompressed on the upstroke of the diaphragm  54  by the diaphragm  54 . The pressurized gas applies a distributed load on the non-working fluid side (top side) of the diaphragm  54  which in turn applies an equal force on the working fluid side (bottom side) of the diaphragm  54  in the first chamber  52  to increase the working fluid pressure in the first chamber  52 . For example, if the second chamber  66  is charged with 100 PSI of gas, this charge can add 100 PSI to the working fluid pressure within the first chamber  52 . This increase in working fluid pressure is additive to the change in working fluid pressure caused by the mechanical drive force applied by the motion of the diaphragm  54  as driven by the drive mechanism via the drive rod  28 . 
     Providing the gas charge in the second chamber  66  to increase the working fluid pressure increases the output pressure of the modular diaphragm pump system  2  which would otherwise require an increase the horsepower of the motor  4  or change in the drive mechanism. As such, the gas charge allows the fluid pumping system  2  to be smaller and possible more portable while maintaining high performance. Due to the gas charge in the second chamber  66 , the motor  4  and drive mechanism experiences an increase in load during the upstroke due. However, this load occurs at a time when the motor  4  load and drive forces are normally low and does not require increased motor  4  horse power or changed drive mechanism to overcome. 
     The additive pressure due to the gas charge may minimize the pressure differential between the top and bottom sides of the diaphragm  54  which can minimize diaphragm  54  distortion and thereby increase diaphragm  54  life. As an example, a mechanical diaphragm pump having a diaphragm with a 10 square inch surface area that is intended to generate 200 PSI on the working fluid requires 2000 pounds of force from the motor  4  and drive mechanism and creates a 200 PSI a pressure differential across the diaphragm  54  (200 PSI on the bottom side and zero PSI on the top side of the diaphragm  54 ). A high pressure differential across the diaphragm  54  risks distorting the diaphragm  54 . However, if a 100 PSI gas charge is in the second chamber  66 , the motor  4  and drive mechanism need only generate 1000 pounds of force and this creates only a 100 PSI pressure differential across the diaphragm  54  (200 PSI on the bottom side and 100 PSI on the top side of the diaphragm) to generate the same 200 PSI working fluid pressure, thereby decreasing the risk of distorting the diaphragm  54 . 
     The pressurized gas can be introduced to the second chamber  66  via channel  74 . A conventional hose from a conventional compressor or a conventional air tank (not shown), all known in the art, can attach to valve  72  and/or channel  74  (e.g., by a threaded interface) to supply pressurized atmospheric air or gas to the second chamber  66 . In some embodiments, the pressurized gas within the second chamber  66  is provided through the channel  74  soon after the diaphragm pump  6  is assembled and remains in the second chamber  66  during operation (multiple reciprocation cycles) of the diaphragm pump  6  without release or replenishment until the diaphragm pump  6  is disassembled. In some embodiments, the conventional compressor or air tank may, with a conventional pressure regulator, add additional gas as necessary during and/or between reciprocation cycles to respond to user input or account for loss of gas. A pressure sensor may be provided within the second chamber  66  to monitor the pressure within the second chamber  66  and automatically control the conventional regulator to introduce additional gas or release gas via the channel  74  to maintain a pressure level or range. 
     When utilizing the gas charge feature, the second chamber  66  can be sealed such that the pressure within the second chamber  66  remains constant (or near constant) between repeated reciprocation cycles. The static interfaces forming the second chamber  66  are sealed. For example, the diaphragm  54  is sealed about its rim  56  within the first and second covers  22 ,  24 . The diaphragm  54  is also sealed about the plate  64 A. Dynamic interfaces of the second chamber  66  are also sealed. The seal between the drive rod  28  and the pump neck  26  is, at least during pumping, a dynamic seal in that the drive rod  28  moves relative to the pump neck  26 . The seal  68  is in contact with the drive rod  28 . 
     Dynamic sealing is provided by seal  68 . Seal  68  prevents compressed gas (or working fluid if the second chamber encounters fluid being pumped) from escaping the second chamber  66  along the drive rod  28 . Seal  68  is a tubular bellows. The seal  68  can be coaxial with the drive rod  28 . Seal  68  can extend along the drive rod  28 . Seal  68  can surround the drive rod  28  within the second chamber  66 . The seal  68  can be formed from rubber, such as ethylene propylene. Seal  68  can stretch and compress. The seal  68  flexes along repeated waves or folds. Tails are located on opposite ends of the seal  68 . A tail on the top end of the seal  68  is circumferentially pinched by, attached to, or otherwise pressed against the rib  44  and/or the pump neck  26  to seal the top end of the seal  68 . The tail on the top end of the seal  68  can be circumferentially pinched, attached, or presses against other parts of the pump neck  26  or other part of the diaphragm pump  6 . The tail on the bottom end of the seal  68  can be circumferentially pinched by, attached to, or otherwise pressed against the exterior of the drive rod  28  and/or the inside of the plate  64 A to seal the bottom end of the seal  68 . The tail on the bottom end of the seal  68  can be circumferentially pinched, attached, or presses against other parts of the diaphragm pump  6 . Since the seal  68  is a flexible membrane rather than a sliding seal, it is not worn away by abrasive working fluids. 
     As alternatives to seal  68 , a stack of polymer and/or leather rings can be located within a cylindrical space defined within the pump neck  26  and around the drive rod  28 , the rings sealing between the inner surface of the pump neck  26  and the outer surface of the drive rod  28 . The rings stay stationary with either the pump neck  26  or the drive rod  28 , and slide relative to the other of the pump neck  26  or the drive rod  28 . Such rings are shown in  FIG.  7   . In some embodiments, the stack of rings can be replaced by a sleeve or bushing. 
       FIG.  6    is an isometric view of a modular diaphragm pump system  102  similar to that of  FIGS.  1 - 5    except that the diaphragm pump  106  of the embodiment of  FIG.  6    includes an integrated dampener  176 . Components sharing the first two digits of a reference numbers (e.g., 2,  102 ; 6,  106 ; 10,  110 ; 16,  116 , etc.) of different embodiments can have similar configurations amongst the various illustrated and described embodiments, unless otherwise noted or incompatible. For example, the reciprocating power unit  116  can be identical in form and/or function to the reciprocating power unit  16  except for those aspects shown or described to be incompatible. For the sake of brevity, common aspects (e.g., materials, features, functions, properties, etc.) are not repeated for different embodiments even though the different embodiments may share the same aspects. For all referenced embodiments, an aspect described and/or shown for one embodiment can be implemented in another embodiment unless otherwise described or shown to be incompatible. 
     The modular diaphragm pump system  102  of  FIG.  6    includes a reciprocating power unit  116  having a motor  104 , structural frame  108 , pump coupling  110 , wheels  114 , and drive mechanism. The modular diaphragm pump system  102  includes a diaphragm pump  106  which can mount on the pump coupling  110 , and be operated by the reciprocating power unit  116 , in any manner referenced herein. The diaphragm pump  106  includes a main housing  186  onto which a first cover  122  and a second cover  182  are attached. The diaphragm pump  106  includes inlet port  120 . The main housing  186 , the first cover  122 , and the second cover  182  form a housing of the diaphragm pump  106 . Below the second cover  182  and the main housing  186 , and integrated into the diaphragm pump  106 , is a dampener  176 . The dampener  176  is further shown in  FIG.  7   . 
       FIG.  7    is a cross sectional view of the diaphragm pump  106 . The diaphragm pump  106  includes a drive rod  128 , including head  130 , which can make a dynamic connection with a drive mechanism of the modular diaphragm pump system  102 . The diaphragm pump  106  also includes a pump neck  126 . Located between the pump neck  126  and drive rod  128  is a seal  168  formed by a stack of packing rings, as previously described. Nut  112  can be moved along the pump neck  126  for clamping as previously described. The pump neck  126  can be directly attached, or integral and continuous with, first cover  122 . The first cover  122  can be attached to main housing  186 . 
     The diaphragm pump  106  includes a diaphragm  154 A sandwiched between the first cover  122  and the main housing  186 . The first cover  122  is attached (e.g., threaded, bolted, or welded) to the main housing  186 . The diaphragm  154 A is linked to the drive rod  128  such that the center of the diaphragm  154 A moves linearly up and down with the reciprocation of the drive rod  128  while the rim of the diaphragm  154 A stays stationary. In the illustrated embodiment, plates  164 A-B sandwich a center portion of the diaphragm  154 , secured by connector  158 . A side channel  178  can be formed in the main housing  186  as a side branch of the material of the main housing  186  (such a side branch could alternatively be bolted or welded to the main housing  186 ). 
     The diaphragm pump  106  includes a dampener  176 . The dampener  176  includes a cylinder  198 , a piston  190  which linearly moves within the cylinder  198 , and a dampener diaphragm  154 B. The dampener diaphragm  154 B is held between the main housing  186  and the second cover  182 . The second cover  182  is attached to the bottom of the main housing  186  (e.g., threaded, bolted, or welded). The rim of the dampener diaphragm  154 B may be pinched or otherwise held in place between the main housing  186  and the second cover  182 . The dampener diaphragm  154 B is linked to the piston  190  such that the piston  190  moves linearly up and down with the center of the dampener diaphragm  154 B while the rim of the dampener diaphragm  154 B stays stationary. In the illustrated embodiment, plates  164 C-D sandwich a center portion of the dampener diaphragm  154 B. The plates  164 C-D are coupled by connector  158 B which can be a bolt that threads into the respective plates  164 C-D. The bottom plate  164 D can attach (e.g., by threading) to the top of the piston  190 . 
     The diaphragm  154 A divides an interior space defined by the main housing  186  and the first cover  122  into a first chamber  152  and a second chamber  166 . A dampener diaphragm  154 B divides an internal space defined by the main housing  186  and the second cover  182  into a third chamber  180  and a fourth chamber  184 . The diaphragm  154 A seals the first chamber  152  with respect to the second chamber  166  such that fluid does not flow or leak from the first chamber  152  to the second chamber  166 . Likewise, the dampener diaphragm  154 B seals the third chamber  180  with respect to the fourth chamber  184  such that fluid does not flow or leak from the third chamber  180  to the fourth chamber  184 . In this way, fluid flows from the inlet port  120  to the outlet port  118  without loss of fluid. 
     The diaphragm pump  106  is shown to include two check valves  160 ,  162  to allow the diaphragm  154 A to productively draw fluid through inlet port  120 , past check valve  162 , around the side channel  178 , through the first chamber  152  (the pumping chamber), past the check valve  160 , through the third chamber  180 , and out the outlet port  118 . In this way, the fluid is pumped upstream-to-downstream, the inlet port  120  representing the upstream direction and the outlet port  118  representing the downstream direction. In operation, the bottom side of the diaphragm  154 A contacts working fluid but the top side of the diaphragm  154 A does not. The diaphragm pump  106  operates by the movement of the diaphragm  154 A making the first chamber  152  alternately larger and smaller. Specifically, when the drive rod  128  is on the upstroke, the upward motion of the diaphragm  154 A increases the volume of the first chamber  152  and pulls upstream working fluid past check valve  162  and into the first chamber  152 . This is reversed on the down stroke when the diaphragm  154 A moves downwards to decrease the volume of the first chamber  152  to force working fluid in the first chamber  152  downstream past check valve  160 . Check valves  160 ,  162  prevent retrograde downstream-to-upstream fluid flow. Working fluid expelled from the first chamber  152  flows through the side channel  178  and then into the third chamber  180 . The cyclical movement of the diaphragm  154 A causing alternating suction and expelling phases can cause undesirable downstream pressure and flow pulsations. The dampener  176  is provided to reduce downstream pressure variations and create constant fluid flow. Specifically, the dampener diaphragm  154 B moves to reduce downstream flow pulsation (e.g., pressure and/or flow pulsation out of the outlet port  118 ) due to upstream flow pulsation created by movement of the diaphragm  154 A. 
     As the fluid flow out of the first chamber  152  increases and decreases in a pulsating manner, the dampener diaphragm  154 B flexes to dampen the pressure spikes and to store and release fluid during the suction stroke of the diaphragm  154 A in the first chamber  152 . The dampener diaphragm  154 B is attached to an air control spool by connector  158 B that can increase or decrease the air pressure in the fourth chamber  184  to maintain the optimum dampening effect as the diaphragm  154 A in the first chamber  152  is cycled back in forth. The dampener  176  operates by the center of the dampener diaphragm  154 B moving downward when the pressure within the third chamber  180  spikes and moving upward when the pressure in the third chamber  180  drops to buffer the pressure in the third chamber  180 . For example, when the pressure in the third chamber  180  spikes above the pressure within the fourth chamber  184 , the higher pressure in the third chamber  180  pushes the dampener diaphragm  154 B downward to increase the size of the third chamber  180 , thus momentarily lowering the pressure within the third chamber  180  and decreasing flow through the third chamber  180 . When the pressure in the third chamber  180  drops below the pressure within the fourth chamber  184 , pressure within the fourth chamber  184  moves the dampener diaphragm  154 B upward to decrease the size of the third chamber  180 , thus momentarily raising the pressure within the third chamber  180  and increasing flow through the third chamber  180 . The piston  190  has some range of motion while the pressure within the fourth chamber  184  is maintained. However, the piston  190  forms part of an air control spool that can increase or decrease the air pressure in the fourth chamber  184  in order to maintain the optimum dampening effect. 
     The position of the piston  190  is controlled in part by the pressure within the third chamber  180  and the fourth chamber  184 . The pressure within the fourth chamber  184  can be changed based on the position of the piston  190 . A pneumatic input port  194 A of the cylinder  198  accepts pressurized air (or a fluid under pressure) from a conventional compressor, tank, or other supply (not illustrated) known in the art. The piston  190  has a first seal  192 A, a second seal  192 B, and a third seal  192 C. These seals  192 A-C can each be an O-ring that seals between the piston  190  and the cylinder  198 . The dampener  176  does not accept the flow of pressurized air from the pneumatic input port  194 A as long as the pneumatic input port  194 A is between the first and second seals  192 A-B. However, if the pressure in the third chamber  180  is greater than the pressure in the fourth chamber  184 , then the dampener diaphragm  154 B will be pushed downward which will move the piston  190  downward as well. If the disparity in pressure is great enough, the first seal  192 A will pass the pneumatic input port  194 A and then pressurized air will flow into a recess  196  between the cylinder  198  and the piston  190  and then into the fourth chamber  184  to increase the pressure in the fourth chamber  184  and cause the dampener diaphragm  154 B to move upwards. The first seal  192 A then moves up past the pneumatic input port  194 A to stop the flow from the pneumatic input port  194 A. The fourth chamber  184  then remains at the higher pressurized and sealed to continue to buffer the pressure and flow within the third chamber  180 . 
     The fourth chamber  184  can be partially or completely exhausted to relieve pressure on the third chamber  180  via the dampener diaphragm  154 B. Specifically, if the pressure within the third chamber  180  drops enough, the higher pressure within the fourth chamber  184  causes the dampener diaphragm  154 B to move upwards, lowering the volume and momentarily increasing the pressure within, and flow through, the third chamber  180 . To prevent the dampener diaphragm  154 B from moving too far upwards, an exhaust port  194 B is in fluid communication with the fourth chamber  184 . The exhaust port  194 B is ordinarily prevented from exhausting by the second and third seals  192 B-C. However, if the third seal  192 C and/or the bottom of the piston  190  moves above the exhaust port  194 B, pressure can be relieved from the fourth chamber  184  as air exhaust through the exhaust port  194 B and within the cylinder  198  below the piston  190  to atmosphere. Eventually, the pressure within the third chamber  180  becomes higher than the pressure in the fourth chamber  184 , at which point the dampener diaphragm  154 B will be forced downwards and the third seal  194 B and/or piston  190  will once again seal the exhaust port  194 B. 
     The dampener  176  is an integrated part of the diaphragm pump  106 . Dismounting of the diaphragm pump  106  from the reciprocating power unit  116  necessarily includes removal of the dampener  176  from the reciprocating power unit  116 . Likewise, mounting of the diaphragm pump  106  on the reciprocating power unit  116  includes mounting the dampener  176 . The dampener  176  is attached to the second cover  182  (e.g., threaded, bolted, or welded) such that the dampener  176  is indirectly attached to the main housing  186 . In some embodiments, the second cover  182  is omitted and the dampener  176  is attached directly to the main housing  186 . The main housing  186  and the dampener  176  are fixed to one another and are part of the same integrated fluid pumping module. The main housing  186  contacts, and secures by pinching, both of the pumping diaphragm  154 A and dampener diaphragm  154 B. The first chamber  152  of the diaphragm pump  6  and the third chamber  180  of the dampener  176  share a common wall  188  of the main housing  186 . 
     The integration of the dampener  176  with the diaphragm pump  106  minimizes the length and complexity of the fluid path between the diaphragm pump  6  and the dampener  176  to increase the ability of the dampener  176  to buffer pressure extremes. For example, once working fluid exits the check valve  160 , the working fluid need only round two 90 degree bends (or one 180 degree turn-around) of the side channel  178  to encounter the third chamber  180  of the dampener  176 . No external hoses or tubes are needed to connect the fluid path between the first and third chambers  152 ,  180 . This short distance minimizes the potential for leaks to develop along the fluid path and ensures responsiveness of the dampener  176 . 
     Several components are aligned in this integrated assembly of the diaphragm pump  106 . Each of the diaphragm  154 A, the dampener diaphragm  154 B, the drive rod  128 , the piston  190 , the cylindrical pump neck  126 , and the cylinder  198  are coaxially aligned. Coaxial alignment of these moving and non-coming parts can help balance the diaphragm pump  106  and minimize vibration during operation. 
     Although “top” and “bottom”, “up” and “down”, and “upstream” and “downstream” are used herein for convenience to correspond to the orientations shown, these and other embodiment need not have such orientation. For example, for parts having “top” and “bottom” designations herein, “first” and “second” designations can alternatively be used. 
     The present disclosure is made using different embodiments to highlight various inventive aspects. As such, the disclosure presents the inventive aspects in an exemplar fashion and not in a limiting fashion. Modifications can be made to the embodiments presented herein without departing from the scope of the invention. For example, a feature disclosed in connection with one embodiment can be integrated into a different embodiment. As such, the scope of the inventions are not limited to the embodiments disclosed herein.