Patent Publication Number: US-2016230904-A1

Title: Fluid control systems employing compliant electroactive materials

Description:
FIELD OF THE INVENTION 
     The present invention relates to fluid control systems employing compliant electroactive materials. In particular, it relates to valves constructed of transducers made of compliant electroactive materials. 
     BACKGROUND 
     There are many types of conventional valve systems where flow through the valve is controlled by a valve actuator, such as a solenoid actuator, piezoelectric actuators, stepper actuators, etc. 
     With solenoid-controlled valves, a plunger made of magnetic material is slidable within a solenoid coil, and a spring or other biasing means urges the plunger into contact with a valve seat or seal, or visa-versa. When no current is supplied to the solenoid, the valve is maintained closed by the spring if a normally-closed valve, and open if a normally-open valve. When current flows in the solenoid, a magnetic force acts against the spring to move the plunger, the end of which is often referred to as a poppet or orifice, away from or towards the valve seat, depending on the valve&#39;s normal position when the solenoid is in its off state. When the magnetic force exceeds the force of the spring, the poppet is moved out of (or into) contact with the valve seat to a remote (or adjacent) position in which the valve is fully open (or fully closed). Such a valve (whether normally closed or normally open) has essentially only two states, open and closed. 
     A proportional valve is one in which the plunger/poppet moves relative to the valve seat in a controlled manner whereby the flow rate through the valve varies in proportion to the current supplied to the solenoid. Such a valve is desirable for many applications in which a gradual or graded variation in flow is preferable to discrete on and off states where the transition between the on and off states is immediate. 
     Because many valve applications involve the passage of fluid from a chamber or source having an overall greater volume to one having a lesser volume, the pressure on the inlet or upstream side of a valve is typically greater than on its outlet or downstream side. As a result, the work (force×stroke) required of the actuator to maintain the valve in the open or closed position (depending on the valves bias, i.e., naturally open or naturally closed) is necessarily greater than the amount of work that would be required in a balanced environment, i.e., where the fluid pressure on the inlet and outlet sides is substantially equal. Furthermore, in the context of a proportional valve, this unbalanced condition affects the ability to precisely control the opening and closing of the valve seat. 
     Another consideration in determining valve design is the need in most cases to prevent the fluid medium, particularly liquids, from contacting the conductive and mechanical portions of the actuator and valve mechanisms to ensure proper performance of the valve and to prevent corrosion and shorting of the electrical/electronic based components of the actuator and valve. This also serves to prevent contamination of the fluid by the valve and actuator components, such as in medical applications. Providing this so-called “non-wetted” environment typically involves positioning these components more remotely from the remaining valve armature or, alternatively, isolating them with a protective barrier. Because of the extra force created by the added distance and/or the barrier, such non-wetted valve systems are relatively less efficient. See, e.g., U.S. Pat. No. 5,375,738 which discloses a non-wetted solenoid valve. 
     The advent of dielectric elastomer materials, also referred to as “electroactive polymers” (EAPs), has provided significant advancement in many transducer-based technologies. U.S. Pat. Nos. 7,394,282, 7,362,032; 7,320,457, 7,259,503, 7,064,472, and 7,052,594 and U.S. Published Patent Application Nos. 2007/0200457, 2007/0200468, and 2006/0208610 disclose various EAP transducer configurations for use in valves and other fluid control mechanisms. The size, weight, power, heat generation, controllability, environmental and cost benefits and advantages of EAP transducer-based valves are significant over other conventional valves. 
     Accordingly, it would be desirable to provide EAP-based fluid control systems to further improve upon the state of the art by addressing some of the shortcomings of existing valve systems. In particular, it would be advantageous to provide EAP-based valve mechanisms which are employable in applications in which more complex valve mechanisms, such as proportional valves, are not readily used. Additionally, it would be highly advantageous to provide the EAP material in a non-wetted, fluidly sealed manner that reduces the overall form factor of the system while not decreasing its efficiency. 
     SUMMARY OF THE INVENTION 
     The present invention includes fluid control systems and devices utilizing one or more EAP transducers to adjust or modulate at least one parameter of the fluid being controlled. 
     These systems and devices include at least one fluidic conduit to provide at least a portion of a flow path for allowing the fluid to travel through the system/device and one or more valves for controlling one of flow rate, flow direction, fluid temperature and combinations thereof of the fluid through the flow path. The systems and devices also include at least one EAP transducer associated with the fluidic flow path, wherein activation of the EAP transducer affects the desired fluid parameter(s). 
     In one variation, the fluid control system functions as a highly tunable proportional valve in which the fluid flow through the valve is proportional to the amount of voltage applied to and the displacement produced by the EAP transducer. 
     In another variation, the fluid control system, whether proportional or not, is operable in a non-wetted environment. To this end, the systems and devices may further include one or more barriers designed or configured to fluidly isolate a surface of the EAP transducer from constituents of the fluid being controlled by the system or device or otherwise in proximity thereto. The barrier may be designed or configured to attach to the one or more transducers or another structure of the system. 
     In any of the fluid control systems of the present invention, the EAP-based actuators may comprise magnetically-coupled elements to open and close valve components. 
     In addition to providing highly tunable devices, EAP-based actuators can be provided in very low profile and versatile form factors which make them ideal for use in complex valve designs. 
     The present invention also includes methods for using the subject devices and systems. 
     These and other features, objects and advantages of the invention will become apparent to those persons skilled in the art upon reading the details of the invention as more fully described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is best understood from the following detailed description when read in conjunction with the accompanying schematic drawings, where variation of the invention from that shown in the figures is contemplated. To facilitate understanding of the invention description, the same reference numerals have been used (where practical) to designate similar elements that are common to the drawings. Included in the drawings are the following figures: 
         FIGS. 1A and 1B  are cross-sectional and exploded views, respectively, of a 2-way fluid control system of the present invention having a balanced configuration; 
         FIGS. 2A and 2B  are cross-sectional and exploded views, respectively, of a 2-way fluid control system of the present invention having an unbalanced configuration; 
         FIGS. 3A and 3B  are cross-sectional and exploded views, respectively, of a 3-way fluid control system of the present invention having a balanced configuration; 
         FIGS. 4A-4F  are various views of a fluid control system of the present invention and several of its components; 
         FIGS. 5A-5D  are side, perspective, cross-sectional and exploded views, respectively, of a fuel injector employing a fluid control system of the present invention; 
         FIGS. 6A-6C  are side, perspective and cross-sectional views, respectively, of a fuel injector employing another fluid control system of the present invention; 
         FIGS. 7A and 7B  are cross-sectional schematic representations of passive and active states of another fluid control system of the present invention employing a magnetically-coupled actuator; and 
         FIG. 8  is a cross-sectional view of another fluid control system of the present invention which employs a sealing spring to prevent valve leakage. 
     
    
    
     Variation of the invention from that shown in the figures is contemplated. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Exemplary embodiments and features of the inventive fluid control system and devices are now described to illustrate broadly applicable aspects of the present invention. With any variation of the invention, the fluid being controlled or acted upon by the subject devices may include one or more of a liquid, a gas, a plasma, a flowable solid, a phase change and combinations thereof. 
     With reference to the  FIGS. 1A and 1B , there is shown a fluid control system  10  of the present invention which functions as a two-way valve to allow passage of fluid from one location or chamber to another location or chamber, where the valve may be operated to allow flow in either direction through it. Fluid control system  10  includes a main housing or valve body  12  having an inlet port  14  and an outlet port  16 , which may be positioned about housing  12  at any in-plane angle with respect to each other. Inlet port  14  leads to and is in fluid communication with a first or inlet chamber  18  within housing  12  and in which sits a plunger mechanism extending and movable in the axial direction of system  10 . The plunger mechanism includes a poppet  20  driven by a plunger core or connection stem  46 . Poppet  20  provides a centrally located, generally disc-shaped inset or seat within which a seal pad  22  is held. When the valve is in the closed position (as illustrated in  FIG. 1A ), seal pad  22  abuts a valve seat  24  positioned at the innermost end of stem  26  and having a cross section, e.g., tapered, to provide optimal sealing and flow stability and control. Conversely, when the valve is in the open position (not shown), a gap or spacing is provided between seal  22  and seat  24  to allow the passage of fluid from the inlet chamber  18  through an orifice  42  in valve seat  24  into axial passage  28 . Passage  28  extends from valve seat  24  through the stem body  26  and is in fluid communication with a radial or lateral passage  30  extending transversely within stem body  28 . Radial passage  30  opens into a second or outlet chamber  32  which in turn is in fluid communication with outlet port  16 . Stem  26  may be threadably coupled to housing  12  to allow its axial position to be adjusted and, thus, allowing the pre-load placed on seal pad  22  to be adjustable or calibrated. The outer end  35  of stem  26  may provide an external detent  37  to receive a tool for this purpose. Positioned about the outer diameter of stem  26  are two O-rings  34 ,  36 , one on each side of radial passage  30 , to seal the space and prevent leakage between stem  26  and valve body  12 . Grooves within or rails  40  extending from the outer surface of stem  26  may be provided to maintain the position of the O-rings, i.e., to prevent the O-rings from sliding along stem  26 . A bias spring  38  is confined within the inlet chamber  18  between a radially extending shoulder  44  at the back end of poppet  20  and the forward chamber wall  45 . Bias spring  38  acts to bias or preload the plunger mechanism away from valve seat  24  and defines the limit of inward movement by the plunger. 
     The primary fluid flow path defined by valve  10  is as follows: pressurized fluid entering inlet  14  flows into first chamber  18  and, when valve seat  24  is open, passes through it into the axial passage  28  within stem  26 . The fluid then flows into outlet chamber  32  by way of the radial passage  30  within the stem, and then supplied to outlet port  16 . The rate of flow of the fluid through the primary flow path is dictated by the pressure differential between inlet chamber  18  and outlet chamber  32 . This system also provides a secondary fluid flow path, also referred to as a venting pathway described in detail below, for purposes of venting the primary path for the purpose of balancing the pressures between the inlet and outlet sides of the system. 
     The components identified and discussed thus far collectively make up a valve assembly of system  10 . The valve assembly is operated by the actuator assembly  50  (identified in whole in  FIG. 1B ) of system  10 . More specifically, the actuator acts to axially translate plunger  20  to vary the distance between poppet seal  22  and valve seat  24 . The plunger core  46  is used to interface the valve assembly with the system&#39;s actuator. An O-ring  52  may be positioned between the distally or forward facing end of the plunger core  46  and an inwardly extending intermediate wall of poppet  20  to better secure the plunger core within the poppet. 
     Actuator  50  (identified in whole in  FIG. 1B ) is constructed, at least in part, from one or more EAP-based transducers  56 . The transducers include an electroactive polymer film  65  comprised of two thin film electrodes having elastic characteristics and separated by a thin elastomeric dielectric polymer. The EAP film is stretched between outer and inner frame members  48   a ,  48   b . When a voltage difference is applied to the electrodes, the oppositely-charged electrodes attract each other thereby compressing the polymer dielectric layer therebetween. As the electrodes are pulled closer together, the dielectric polymer film becomes thinner (the z-axis component contracts) as it expands in the planar directions (the x- and y-axes components expand). Furthermore, the like (same) charge distributed across each elastic film electrode causes the conductive particles embedded within that electrode to repel one another, thereby contributing to the expansion of the elastic electrodes and dielectric films. 
     In the illustrated exemplary embodiment, three EAP diaphragm transducers  56  are stacked together to form the actuator  50 ; however, any suitable number may be employed depending on the operating parameters desired. The stacked outer frames  48   a  of the transducers are coupled together by means of opposing outer/proximal and inner/distal clamps  58   a ,  58   b  which are in turn secured to the valve body  12  by means of housing end cap  62  and screws  64  (illustrate in  FIG. 1B ). The stacked inner frames  48   b  are coupled together by means of opposing outer/proximal and inner/distal pistons  60   a ,  60   b  which are in turn held between the head  66  of plunger core  46  and shoulder  44  of poppet  20 . Pistons  60   a ,  60   b  are biased outward in the direction of arrow  67  by the force placed on plunger  20  by biasing spring  38 , thereby forming a frustum-shaped actuator cartridge when in an inactive or natural state. 
     As explained above, when a voltage is applied to actuator  50 , the diaphragm film  65  is expanded in a planar direction (perpendicular to the axial dimension of device  10 ) which allows the bias on spacer pistons  60   a ,  60   b  to further translate them in the direction of arrow  67 . This in turn biases the core head  66  “upward” which then “lifts” the plunger mechanism along with it. The amount of lift defines the distance between the poppet seal  22  and valve seat  24 . The flow rate of fluid through the valve, in turn, is proportional to the lift distance and the actuator stroke or displacement in the direction of arrow  67 . Thus, the greater the stroke/displacement, the greater the flow. Because the amount of voltage applied to actuator  50  can be controlled, i.e., varied, the lift distance of the poppet can be adjusted proportionally to the applied voltage to provide a highly tuned proportional valve. 
     The force exerted on the plunger is dependent upon the pressure on the fluid and the orifice area of valve seat  24 . When a higher pressure is desired, the amount of work (force×stroke) the actuator is capable of doing is a critical operating parameter. When a fast response or high cycle rate is necessary, the peak and average power outputs (work/time and/or work×frequency) of the actuator and power supply are two critical operating parameters. 
     A feature of the present invention is the provision of actuator  50  in a non-wetted environment within the overall valve system  10 . To this end, fluid impermeable diaphragms are used as barriers between actuator  50  and the fluid pathway through the valve system. An outer diaphragm  70   a  is provided on the outer end of actuator  50  to protect it from fluid that enters into balancing or overflow chamber  74 . An inner diaphragm  70   b  is provided between the inner end of actuator  50  and valve housing  12  and the shoulder  44  of poppet  20  to prevent contact with fluid within inlet chamber  18 . The outer and inner edges of the annular diaphragms are hermetically sealed by the clamping force provided by plunger core  46  and screws  64  (illustrated  FIG. 1B ) to prevent any leakage of fluid into the actuator. Convolutions  72   a ,  72   b  provide the necessary slack in the barrier diaphragms to accommodate the upward displacement of spacer pistons  60   a ,  60   b  and inner actuator frames relative to clamps  58   a ,  58   b  and outer actuator frames. The convolutions extend inward within the spacing between the clamps and pistons. 
     As mentioned above, this valve system is further equipped with a means of venting a portion of the pressure/fluid volume from the inlet side of the system to bring it more in balance with the pressure on the outlet side of the system. This venting pathway includes a radial or lateral bore  47  extending through the diameter of poppet  20 , through the lumen  54  of plunger core  46  and into balancing chamber  74  defined between cap  62  and plunger core head  66  and sealed from actuator assembly  50  by barrier diaphragm  70   a . By balancing the pressure between inlet cavity  18  and balance cavity  74 , the force resulting from pressure in cavity  18  and is prevented from otherwise acting upon poppet assembly  20  in the direction of arrow  67 . By venting a volume of fluid from inlet cavity  18  into balancing chamber  74 , the pressure within inlet cavity  18  is reduced and prevented from otherwise acting upon poppet assembly  20  in the direction of arrow  67 . 
     There are applications in which an unbalanced valve design is preferred, such as when it is intended to function as a pressure regulator. In pressure regulated valve systems, the direction of fluid flow is typically in one direction only, with a pressure differential typically resulting by design from a greater pressure on the inlet side than on the outlet side. Such functionality is commonly used in fluid delivery systems such as automobile fuel lines, industrial automation pneumatic systems, medical breathing apparatus, etc. 
       FIGS. 2A and 2B  illustrate such an unbalanced valve design. Fluid control system  80  has a valve assembly and actuator assembly construct which are substantially similar that of the balanced fluid control system  10  of  FIGS. 1A and 1B , where like reference numbers are used to identify like components between the two systems and, as such, may not be described again with respect to system  80 . 
     In system  80 , the direction of fluid flow is reversed from that which is illustrated for system  10 , with the inlet port  92  being positioned at a more distal location on the valve body  12  than the outlet port  96 . Thus, the fluid flow path defined by valve  80  is as follows. Pressurized fluid entering inlet  92  flows into inlet chamber  94  by way of radial passage  30  within the stem body  26 . The fluid then passes through axial passage  28  within stem body  26 . When valve seat  24  is open, the fluid enters into outlet chamber  98  then flows out of outlet port  96 . 
     Actuator  50  (illustrated in whole in  FIG. 2B ) of system  80  has a construct similar to the actuator of system  10  of  FIGS. 1A / 1 B with an EAP film  65  stretched between outer and inner frame members  48   a ,  48   b . The stacked outer frames  48   a  of the transducers are coupled together by means of opposing outer/proximal and inner/distal clamps  90   a ,  90   b  which are in turn secured to the valve body  12  by means of housing end cap  62  and screws  64  (illustrated in  FIG. 1B ). The stacked inner frames  48   b  are coupled together by means of opposing outer/proximal and inner/distal pistons  60   a ,  60   b  which are in turn held between the head  66  of plunger core  46  and shoulder  44  of poppet  20 . Pistons  60   a ,  60   b  are biased outward in the direction of arrow  67  by the force placed on poppet  20  by biasing spring  38 , thereby forming a frustum-shaped actuator cartridge when in an inactive or natural state. 
     The larger internal dimensions of the assembled end cap provide a clearance between the inner wall of the end cap and outer/proximal piston  88   a  which is greater than the clearance between inner/distal piston  88   b  and inner/distal transducer clamp  90   b . As such, and unlike the balanced system of  FIGS. 1A / 1 B, the volume of overflow chamber  84  is greater than outlet chamber  98 . 
     Pressure regulating functionality is obtained by use of the outlet pressure as a controlling element by means of creating a closing force between poppet  22  and orifice  24  resulting from the larger pressure area of outer diaphragm ( 100   a ,  102   a ) creating a greater force, counteracting the weaker resultant force from the smaller inner diaphragm ( 100   b ,  102   b ), the two opposing forces are coupled though the outer piston  88   a , the actuator stack  50  and inner piston  88   b . The combination of the force resulting from this pressure imbalance, the force of the EPAM actuator and the force of the bias spring  38  results in a system at equilibrium which can be altered by two means—a pressure change in the balance chamber  84  which communicates with the outlet port through passages  54  and  47  or application of a voltage to the EPAM actuator. 
       FIGS. 3A and 3B  illustrate a fluid control system  110  of the present invention having a balanced configuration and which allows passage of fluid between three locations, where the direction of fluid flow is controlled by the operation of two valves. Fluid control system  110  includes two valve bodies  112   a ,  112   b  (which are referred to respectively herein as a lower valve body and an upper valve body based solely on the point of reference of the figures, where such nomenclature does not limit or require use of the system in such a lower/upper orientation) positioned on opposing sides of an actuator assembly  150 , which are collectively secured together by screws  164  (shown in  FIG. 3B  only). While two valves are employed, only a single poppet/plunger mechanism extending between the valve bodies is used. The plunger mechanism is primarily defined by a plunger core  146  extending between symmetrically disposed lower and upper poppets  120   a ,  120   b . The plunger mechanism is configured to operate bi-directionally to respectively open and close the system&#39;s two valves. 
     The construct of the two valve body portions  112   a ,  112   b  are substantially similar; however, only one of them ( 112   a ) houses a bias spring for biasing the actuator, i.e., in the direction of arrow  145   a . The designs of the valve bodies are now described collectively. Each valve body has an inlet port  114   a ,  114   b , respectively, and an outlet port  116   a ,  116   b , respectively, which ports may be positioned about there respective housings at any angle with respect to each other. In the illustrated example, inlet ports  114   a ,  114   b  are used in tandem whereby fluid enters both ports simultaneously from one or more sources, and whereby the outlet ports  116   a ,  116   b  are used separately, flow rate of one being the inverse of the other. Rather, as will be better understood from the discussion below, fluid control system  110  attenuates the amount of fluid exiting each outlet port whereby one outlet port may be completely closed (outlet port  114   a ) while the other is completely open (outlet port  114   b ), or where both outlet ports may be partially open to varying degrees relative to each other. Alternatively, the system may be configured such that ports  114   a ,  114   b  are employed as fluid outlets and ports  116   a ,  116   b  are used as fluid inlets. Such a versatile system enables three-way fluid control. 
     Each inlet port  114   a ,  114   b  leads to and is in fluid communication with an annularly configured first or inlet chamber  118   a ,  118   b , within which sits the poppet component  120   a ,  120   b  of the poppet/plunger mechanism. Each poppet  120   a ,  120   b  provides a centrally located, generally disc-shaped inset within which a seal pad  122   a ,  122   b  is held. When a valve is in the closed position (such as the lower valve  112   a  is illustrated in  FIG. 2A ), seal pad  122   a ,  122   b  abuts a tapered valve seat  124   a ,  124   b  positioned at the innermost end of stem  126   a ,  126   b . Conversely, when the valve is in the open position (such as the upper valve  112   b  is illustrated in  FIG. 2A ), a gap or spacing is provided between seal  122   a ,  122   b  and seat  124   a ,  124   b  to allow for the passage of fluid from the inlet chamber  118   a ,  118   b  through an orifice  142   a ,  142   b  in valve seat  124   a ,  124   b  into an axial passage  128   a ,  128   b . Passage  128   a ,  128   b  extends from valve seat  124   a ,  124   b  through stem body  126   a ,  126   b  and is in fluid communication with a radial or lateral passage  130   a ,  130   b  extending transversely within stem body  126   a ,  126   b . Radial passage  130   a ,  130   b  opens into a second or outlet chamber  132   a ,  132   b  which in turn is in fluid communication with outlet port  116   a ,  116   b . To maintain a pressure balance between the two inlet sides of system  110 , fluid communication is provided between the two sides by way of lumen  172  within plunger core  146  and passages  166   a ,  166   b  extending laterally through the diameter of each of poppets  120   a ,  120   b.    
     Stems  126   a ,  126   b  may be threadably coupled to their respective housings  112   a ,  112   b  to allow for adjustment of their axial positions and, thus, allow for the pre-load placed on seal pads  122   a ,  122   b  to be adjustable. The outer ends  135   a ,  135   b  of stems  126   a ,  126   b  may have an external detent  137   a ,  137   b  to receive a tool for this purpose. Positioned about the outer diameter of each stem  126   a ,  126   b  are two O-rings  134   a ,  134   b  and  136   a ,  136   b , one on each side of radial passage  130   a ,  130   b , to seal the space and prevent leakage between stem  126   a ,  126   b  and valve body  112   a ,  112   b . Grooves in or rails on  140   a ,  140   b  the outer surface of stem  126   a ,  126   b  may be provided to maintain the position of the O-rings, i.e., to prevent the O-rings from sliding along the stem. 
     As mentioned above, because only a single plunger mechanism is employed with this system, only a single actuator assembly  150  is necessary; however, multiple actuator systems are also within the scope of the present invention. Actuator assembly  150  includes an actuator having a stacked set of transducers similar to that of the two previously-described fluid control systems. The stacked outer transducer frames  148   a  are coupled and held together by means of opposing lower and upper clamp structures  158   a ,  158   b  which are in turn held between the valve bodies  112   a ,  112   b . The inner transducer frames  148   b  are coupled together by means of opposing lower and upper pistons  160   a ,  160   b  which are in turn held between lower and upper poppet shoulders  144   a ,  144   b . A bias spring  138  is confined within inlet chamber  118   a  between poppet shoulder  144   a  and the forward chamber wall  168 . Bias spring  138  acts to force poppet  120   a  in the direction of arrow  145   a , which moves pistons  160   a ,  160   b  in the same direction, thereby biasing or preloading the actuator in the frustum configuration discussed previously. As such, actuator assembly  150  acts to axially translate the plunger core  146  to vary the distance, respectively, between the poppet seals  122   a ,  122   b  and their opposing valve seats  124   a ,  124   b . O-rings  152   a ,  152   b  may be positioned between the respective ends of the plunger core  146  and inwardly extending intermediate shoulders  154   a ,  154   b  of poppet  120   a ,  120   b  to further secure the plunger core within the plunger mechanism. 
     In one variation, the natural bias on the actuator, i.e., when the actuator is in an inactive state, is selected to maintain the plunger mechanism in an axial position whereby one valve (the lower valve in the illustrated embodiment) is normally closed while the other valve (the upper valve in the illustrated embodiment) is normally open. When a voltage is applied to the actuator, the transducer films are expanded in a planar direction, which allows them to be further stretched thereby enabling the plunger mechanism as a whole to translate further in the direction of arrow  145   a  and thereby moving lower poppet seal  122   a  away from lower valve seat  124   a  and moving upper poppet seal  122   b  toward upper valve seat  124   b . The amount of translation undergone by the plunger mechanism in either axial direction  145   a  or  145   b  can be controlled to thereby selectively vary the distance between the poppet seals  122   a ,  122   b  and their opposing valve seats  124   a ,  124   b . The respective fluid flow rates from the inlet ports to the outlet ports can thus be attenuated as desired. 
     As with the other fluid control systems of the present invention, system  110  may be configured with the actuator assembly  150  in a non-wetted environment. To this end, lower and upper hermetically sealed and convoluted barrier diaphragms  170   a ,  170   b  are provided across the outer frame clamps and plunger pistons of actuator  150  to protect it from fluid entering into inlet chambers  118   a ,  118   b.    
       FIGS. 4A-4F  illustrate a master fluid control system  200  of the present invention for complex fluid control applications involving the movement of fluid to and from multiple locations and sources. Such a system may be useful in dividing an incoming flow into two outputs for proportional position or velocity control of a fluid motion system. 
     System  200  includes a plurality of fluid control devices  202  of the present invention integrated with a fluid manifold block  204 . The fluid control devices  202  include regulators  202   a  (such as the regulator of  FIGS. 2A / 2 B) and/or valves  202   b ,  202   c  (such as the valve devices of  FIGS. 1A / 1 B). As illustrated in  FIG. 4D , each of the fluid control devices  202  has two fluid inlet-outlet ports  214   a ,  214   b  within the valve body  210  where one port is used for fluid inlet and the other for fluid outlet. The fluid manifold block  204  may include any number of manifold portions  205  to accommodate the number of fluid control devices  202  to be used. Each manifold portion  205  has two fluid inlet-outlet ports  206   a ,  206   b , where port  206   a  functions as an inlet port and port  206   b  functions as an outlet port when coupled to a valve device  202 , and visa-versa when coupled to a regulator device  202 . As all ports  206   a  within manifold block  204  are in serial alignment and fluid communication, they collectively function as a shared pressure rail which can receive flow at regulated pressure from the outlet of a regulator  202   a  connected to any of the ports  206   a . When system  200  is assembled, each pair of valve inlet-outlet ports  214   a ,  214   b  is aligned with a corresponding pair of manifold inlet-outlet ports  206   a ,  206   b . The control devices  202  are each mechanically secured to manifold block  204  by way of fasteners  218 . 
     System  200  further includes an electrical interconnect block  232  mechanically interfaced with fluid manifold block  204 . Electrical interconnect block  232  provides all necessary electrical and electronic coupling between the subject regulators and valves  202   a - 202   c  and the system&#39;s power supply (not shown) and electronic controls (e.g., ICU, etc.) (not shown) via electrical cable  216 . Electrical interconnect block  232  are electronically coupled to and the valve/regulators  202  via electrical connection slots  234  within block  232 . Slots  234  are configured to receive the corresponding electrical connection tabs  220  extending from the actuator portions  212  of the respective valves/regulators  202 . As best illustrated in  FIG. 4D , each connection tab  220  comprises a printed circuit board (PCB)  226  having an opening  224  configured to frame an EAP actuator transducer (not shown). Electrical traces  228  are provided on the PCB  226  for establishing the electrical connection with the transducer electrodes. 
     The manifold inlet-outlet port pairs  205  are selectively employed by the system via the electronic controls to move and direct fluid, where the movement of a single type of fluid between various different sources and destinations is controlled, e.g., an industrial pick and place unit, or where multiple fluid types are selectively moved from various sources to one or more depositories, e.g., gas sampling equipment. 
     The fluid control devices of the present invention are ideally suited for use in fuel injector applications.  FIGS. 5A-5D  illustrate a non-wetted valve device of the present invention integrated within a fuel injector device  300 . The inlet portion of fuel injector housing generally includes inlet body  302  and inlet fitting  306 . The outlet portion of the injector housing generally includes a fixed outlet body  304 , an adjustable outlet body  308  and injector head  310 . The axial position of adjustable outlet body  308  relative to fixed outlet body  304  is adjustable by way of threads  352 . An o-ring  346  may be positioned between adjustable housing  308  and injector head  310  to further secure the head within the housing. Various sets of fasteners  344  (see  FIG. 5D ) are used to secure the housing and other components together. 
     The internal structure of the fuel injector is best described with reference to  FIGS. 5C and 5D . The fluid pathway within the injector begins with inlet passageway  306   a  which extends through a thru-hole  322   a  within screw  322 . The fluid passageway extends within an axial passageway  338   a  of a coupling  338  which is threadedly engaged with screw  322 . The fluid passage way further extends within a pentel  340  which has radially-extending flow passage holes  342 . The passage holes  342  open into an outlet chamber  310   a  within head portion  310  of the injector. Fluid is allowed to flow out of an opening  348  within the distal end of head  310  when the pentel tip  350  is moved proximally (toward the inlet side of the injector) away from opening  348 . 
     The axial movement of pentel  340  is controlled by EAP actuator  314  which encircles screw  322  and coupling  338 . Actuator  314  includes a transducer cartridge comprised of an EAP film  316  extending between outer and inner frame members  312 ,  318 , respectively. Outer frame  312  is held between the inlet and outlet housings  302 ,  304  of the injector. Inner frame  318  is held between a washer  324  held by the head of screw  322  and the proximal end of coupling  338 . Inner frame  318  is biased toward the inlet side of the injector by a coil spring  320 . When the actuator is inactive, pentel tip  350  extends through head opening  348 , i.e., the injector head is normally closed. When the actuator  314  is activated, screw  322 , coupling  338  and pentel  340  are moved in the proximal direction, thereby moving pentel tip  350  out of head opening  348  and enabling fluid within chamber  310  a to exit the fuel injector. The extent to which the fuel injector is open or closed is dependent upon the amount of voltage applied to actuator  314 , where the fully open and fully closed positions of pentel  340  can be manually calibrated by adjusting the either or both of the position of adjustable housing  308  relative to outlet body  304  (by way of threads  352 ) and the position of coupling  338  relative to screw  322  (by way of the screw threads). 
     Actuator  314  is provided in a non-wetted environment by proximal and distal diaphragms  328  and  332 , respectively, the latter of which has a convolution  332   a . The inner portion of proximal diaphragm  328  is secured between washer  324  and a countersink washer  326  on the underside of screw head  322 . The peripheral portion of proximal diaphragm  328  is secured between diaphragm clamp  330  and an inner wall  356  of inlet body  302 . The inner portion of distal diaphragm  332  is secured within washer  336 . The peripheral portion of distal diaphragm  332  is secured between diaphragm clamp  334  and an internally-extending shoulder  358  of outer housing body  304 . 
       FIGS. 6A-6C  illustrate another fuel injector  400 , constructed and functioning similarly to that of fuel injector  300  (with like number referencing similar components) with the addition of an EAP-based pump mechanism  405  of the present invention. Pump  405  regulates fluid inflow from inlet passageway  406   a  of inlet fitting  406  into the injector. Pump mechanism  405  is housed within a pump housing  402  positioned on the proximal end of injector inlet body  302 . These two portions of the injector are physically integrated by way of a pump plate  456 . An end cap  462  covers the proximal end of pump housing  402 . 
     Pump mechanism  405  includes inlet and outlet chamber  470  and  472 , respectively. An inlet valve  454  enables fluid passage from the inlet chamber  470  into an intermediate or pumping chamber  474  by opening thru-holes  464  within pump plate  456 , and an outlet valve  458  enables fluid passage from the pumping chamber  474  to the outlet chamber  472  by opening thru-holes  468  within valve plate  456 . Inlet and outlet valves are oppositely facing umbrella valves having flexible caps  454   a ,  458   b  and stem portions  454   b ,  458   b  which are held within valve plate  456 . The relative fluid pressure within intermediate chamber  474  dictates the opening and closing of valves  454  and  458 , respectively. Specifically, a positive pressure in chamber  474  pushes down on cap  454   a , thereby keeping thru-holes  464  sealed, and pushes up on cap  458   a , thereby unsealing thru-holes  468 . Fluid flow into and out of the intermediate chamber  474 , and thus fluid pressure therein, is controlled by the axial movement of screw  422  which in turn is controlled by EAP-based actuator  414 . 
     Actuator  414  includes a transducer cartridge comprised of an EAP film  416  extending between outer and inner frame members  412 ,  418 , respectively. Outer frame  412  is held between the pump housings  402  and end cap  462 . Inner frame  418  is positioned between biasing spring  420  and the underside of the head of screw  422  and also serves to secure the inner portion of pumping diaphragm  428 . The inner portion of diaphragm  428  is further secured by countersink washer  426 . The peripheral portion of diaphragm  428  is secured between a diaphragm clamp  430  and an inwardly-extending shoulder  476 . Fasteners  460  secure diaphragm  428  and diaphragm clamp  430  to shoulder  476 . 
     When actuator  414  is activated, screw  422  moves axially between a minimum or proximal position and a distal or maximum travel position, with pumping diaphragm  428  expanding and compressing, respectively, thereby increasing and decreasing the volume of pumping chamber  474 . As the volume of chamber  474  increases, a negative pressure is created within it and fluid flows from inlet chamber  470 , through thru-holes  464  and into intermediate chamber  474 . As the volume of chamber  474  is decreased, a positive pressure is created within it causing fluid to flow from it into outlet chamber  472 . Fluid in the outlet chamber then flows into passage  322   a  within injector screw  322 . The remainder of the fluid passage through injector  400  is the same as described with respect to injector  300  of  FIGS. 5A-5D . 
       FIGS. 7A and 7B  illustrate another fluid control device  500  of the present invention employing a magnetically-coupled actuator to open and close a valve. Device  500  includes a valve body  502  having a fluid chamber  520  and inlet and outlet ports  506  and  508 , respectively, in fluid communication therewith. The inlet end of outlet port  508  defines a valve stem  515  terminating in a valve orifice or seat  524 . A poppet assembly  522  positioned within chamber  515  sits atop valve stem  515  with a poppet seal  528  abutting orifice  524  when in a closed position (as shown in  FIG. 7A ). An actuator housing  504  is mounted to valve body  502 , the two of which are separated by a thin plate  518 . Plate  518  is made of a non ferrous material and is sufficiently strong to withstand fluid pressure within fluid chamber  520 . Actuator housing  504  contains EAP transducer which is formed by an EAP film  510  extending between outer and inner frame members  512  and  514 , respectively. Outer frame member  512  is held between actuator housing  504  and plate  518 . Inner frame member  514  carries a centrally disposed magnet  516   a  having its poles (N-S) axially aligned with the poppet-valve mechanism. A second magnet  516   a  situated on the opposite side of plate  518  is carried by poppet assembly  522 . The second magnet  516   a  is axially aligned such that one pair of like poles, e.g., the north poles (N), of the magnets oppose each other, thereby biasing the transducer inner frame  514  and poppet assembly  522  away from each other. At the same time, a biasing spring  526  held between an inner wall of valve housing  502  and a shoulder  530  radially extending from poppet assembly  522  biases the poppet assembly and second magnet  516   b  away from valve seat  524  and towards the transducer and the first magnet  516   a.    
     When the actuator is in a passive or inactive state (as shown in  FIG. 7A ), the biasing force of the transducer film  510  against the first magnet  516   a  is greater than the biasing force of the spring  526  against the second magnet  516   b , with the net force being in the direction of arrow  525   a  (of  FIG. 7A ). As such, when the actuator is inactive, poppet  528  is forced against and closes valve orifice  524 . Upon activation of the actuator (as illustrated in  FIG. 7B ), film  510  expands enough such that the spring bias is greater than the film bias, with the net force now being in the opposite direction—in the direction of arrow  525   b  (of  FIG. 7B ). As such, the two magnets are moved in that direction and poppet  528  is moved away from and opens valve orifice  524 , thereby allowing fluid within chamber  520  to exit outlet port  506 . 
     With the valve systems just described that having a normally closed configuration, the bias force placed on the poppet seal by the system&#39;s actuator is the sole force maintaining the valve orifice in a closed state. As such, any variation in the actuator&#39;s components, e.g., variation in film compliance, spring force, etc., may result in a less than necessary net bias force to maintain the seal between the poppet and the valve orifice. The fluid control device  600  of  FIG. 8  provides one manner in which to rectify such a possibility. 
     Fluid control device  600  includes a valve housing  602  and an actuator housing  604  coupled together by connector  614 . Valve housing  602  defines a fluid chamber  630  and has an inlet port  606  and an outlet port  608 . Actuator housing  604  houses an actuator which may include one or more transducers. Here, the actuator is formed by two stacked transducers, each comprising an EAP film  622  extending between outer and inner frame members  624  and  626 , respectively. The outer transducer frames  624  are held between housing  604  and a cover  620 . Extending from the inner frames  626  axially through connector  614  and into fluid chamber  630  within the valve housing is a poppet  612 . A biasing spring  628  positioned between the underside of frames  626  and an inner wall of housing  604  biases poppet  612  away from valve orifice  610 ; however, the bias of the transducer films  622  is greater than that of bias spring, and thus, the distal end of poppet  612  sits against valve orifice  610  when the actuator is inactive, i.e., the valve is normally closed. As mentioned previously, with any variation in the actuator forces which may reduce the net bias force necessary to ensure that poppet  612  seats against valve orifice  610 , allowing leakage through the orifice from inlet port  606  to enter chamber  630 . To obviate such, device  600  includes a sealing spring  618  encircling the distal end of poppet  612  and which is held between a shoulder within connector  614  and a shoulder  616  extending radially from the distal end of poppet  612 . The bias force of sealing spring  618  is sufficient to compensate for any variance in the actuator bias force to ensure that poppet  612  seals against orifice  610  when the actuator is inactive. When the actuator is activated, EAP films  622  are expanded enabling the bias force of actuator spring  628  to over come that of sealing spring  618 , thereby moving poppet  612  axially away from orifice  610 . Fluid may then travel from inlet port  606 , to chamber  630  and exit outlet port  608 . 
     Methods of the present invention associated with the subject fluid control systems, devices, components and assemblies are contemplated. For example, such methods may include transferring fluid from one chamber to another, selectively controlling the opening of a valve a distance proportional to the displacement of the valve&#39;s actuator, controlling the flow rate of fluid through a valve system, venting fluid from a chamber of a valve assembly, etc. The methods may comprise the act of providing a suitable device or system in which the subject inventions are employed, which provision may be performed by the end user. In other words, the “providing” (e.g., a valve assembly, actuator, etc.) merely requires the end user obtain, access, approach, position, set-up, activate, power-up or otherwise act to provide the requisite device in the subject method. The subject methods may include each of the mechanical activities associated with use of the devices described as well as electrical activity. As such, methodology implicit to the use of the devices described forms part of the invention. Further, electrical hardware and/or software control and power supplies adapted to effect the methods form part of the present invention. 
     Yet another aspect of the invention includes kits having any combination of devices described herein—whether provided in packaged combination or assembled by a technician for operating use, instructions for use, etc. A kit may include any number of valve systems according to the present invention. A kit may include various other components for use with the valve systems including mechanical or electrical connectors, power supplies, etc. 
     As for other details of the present invention, materials and alternate related configurations may be employed as within the level of those with skill in the relevant art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts as commonly or logically employed. In addition, though the invention has been described in reference to several examples, optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention. Any number of the individual parts or subassemblies shown may be integrated in their design. Such changes or others may be undertaken or guided by the principles of design for assembly. 
     Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “an,” “said,” and “the” include plural referents unless the specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as the claims below. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. Without the use of such exclusive terminology, the term “comprising” in the claims shall allow for the inclusion of any additional element—irrespective of whether a given number of elements are enumerated in the claim, or the addition of a feature could be regarded as transforming the nature of an element set forth n the claims. Stated otherwise, unless specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity. 
     In all, the breadth of the present invention is not to be limited by the examples provided. That being said, we claim: