Patent Publication Number: US-2019168039-A1

Title: Air-pressure controlled piston and valve configuration

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 15/714,276, filed on Sep. 25, 2017, and entitled “Pressure Regulating Valve with Incorporated Shut-Off Mechanism and Fluidic Bypass”, which is a continuation-in-part of (a) allowed U.S. patent application Ser. No. 15/206,037, filed on Jul. 08, 2016, and entitled “Dual-Piston Pressure Reducer”, which claims priority to U.S. Provisional Patent Application No. 62/190,630 and has issued into U.S. Pat. No. 9,891,635 and (b) U.S. patent application Ser. No. 15/493,415, filed on Apr. 21, 2017, and entitled “Pressure Reducing Valve with Incorporated Shut-Off Mechanism”, which claims priority to U.S. Provisional Patent Nos. 62/190,630, 62/326,056, and 62/333,451. This application is also a continuation-in-part of U.S. patent application Ser. No. 15/714,406, filed on Sep. 25, 2017, and entitled “Pressure Regulating Valve with Multi-Pronged Piston Assembly,” which is also a continuation-in-part of U.S. patent application Ser. No. 15/206,037 and U.S. patent application Ser. No. 15/493,415. All of such applications are incorporated by reference herein in their entireties. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     Pressure control valves, or pressure regulators, are used to automatically increase, decrease, turn on, turn off, or otherwise regulate the flow of a liquid or gas at certain pressures. In many cases, these valves serve to maintain a reduced outlet pressure regardless of variations in the inlet pressure of the fluid. These types of pressure reducing valves are used primarily for safety purposes and can be implemented in a variety of areas, including the aircraft industry, cooking, the oil and gas industry, and many others. In one application, pressure control valves are used in compressed air foam systems (CAFS) used for firefighting, in which the value may be used to deliver an appropriate quantity of water or a mixture of water and surfactant. Many existing pressure control valves and regulators use a spring loaded poppet valve as the pressure reducing or restrictive element and a diaphragm to sense the pressure changes. A spring is typically used to exert a force on the sensing element and to open the valve. 
     In many cases, fire apparatuses are used in areas of both high pressure hydrants, where it is advantageous to reduce the pressure from the hydrants to the apparatus, and of low pressure hydrants, where it is not advantageous to reduce the pressure from the hydrants. One example would be area of different altitudes, where at lower levels there is more pressure due to the higher head of the water (and vice versa for higher altitude portions of the area). For cases where pressure may vary during use or by use, it is necessary to provide optional means of regulation, where the operator may selectively choose the operation best suited for the particular situation. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to a pressure control valve or flow regulator with an incorporated shut-off mechanism for use between a pressurized liquid source and a pump inlet (the pump inlet being fluidically connected to the pressure regulator outlet). The flow regulator uses a piston with a plate, whereupon application of a pressurized fluid on the plate controls movement of the piston. Rather than a poppet valve, the piston moves axially within a pressure chamber as the pressure regulating component. The piston is capable of moving freely toward and away a sealing port allowing the user to control liquid flow to the flow outlet area. The piston, when positioned entirely forward such that it contacts the sealing port, is able to prevent the flow of liquid into the outlet area altogether. In alternate embodiments, a diaphragm may replace the piston and functional in substantially the same manner. For purposes of describing the invention, however, the term piston will be used. 
     In the preferred embodiment of the present invention, the pressure regulator is fluidically connected to a pressurized fluid supply (such as a pressurized air supply). While it is contemplated that any pressurized fluid may be used (such as air, water, or some other fluid), for ease of describing the invention, various embodiments may be described with reference to pressurized air. The invention, however, is not so limited. More preferably, the pressure regulator is fluidically connected at two points (one on either side of the piston plate), such that application of varying amounts of pressurized fluid on either side of the plate will control the lateral movement of the plate within the pressure chamber. When used in a compressed air foam system, the invention allows the engine powering the system to run at an increased rpm at the same discharge pressure. This provides numerous advantages in practical firefighting applications. 
     In certain implementations of the pressure regulator of the present invention, the flow regulator may further include a hand wheel attached at the rear of the pressure chamber. By turning the hand wheel, a moveable plate within the pressure chamber is brought forward, and thus the available stroke of the piston is reduced. This provides a manual override function for the regulator. When the hand wheel is turned such that the moveable plate is in the most forward position, the piston is held in place against the sealing port such that the flow is cut off entirely; conversely, when the hand wheel is turned such that the moveable plate is in the fully rearward position, full articulation of the piston is possible, thereby allowing full flow through the regulator. 
     These and other features, objects and advantages of the present invention will become better understood from a consideration of the following detailed description of the preferred embodiments and appended claims in conjunction with the drawings as described following: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a first embodiment of the pressure regulator of the present invention in partial cut-away, showing the piston in a closed position. 
         FIG. 2  shows a first embodiment of the pressure regulator of he present invention in partial cut-away, showing the piston in a partially open position. 
         FIG. 3  shows a first embodiment of the pressure regulator of the present invention in partial cut-away, showing the piston in a fully open position. 
         FIG. 4  shows a second embodiment of the pressure regulator of the present invention in partial cut-away, showing the piston in a closed position. 
         FIG. 5  shows a second embodiment of the pressure regulator of the present invention in partial cut-away, showing the piston in a partially open position. 
         FIG. 6  shows a second embodiment of the pressure regulator of the present invention in partial cut-away, showing the piston in a fully open position. 
         FIG. 7  shows a third embodiment of the pressure regulator of the present invention in partial cut-away, showing a controller connected to the pressure regulator for controlling pressure into the pressure chamber of the pressure regulator, the controller being in a first mode configuration. 
         FIG. 8  shows a third embodiment of the pressure regulator of the present invention in partial cut-away, showing a controller connected to the pressure regulator for controlling pressure into the pressure chamber of the pressure regulator, the controller being in a second mode configuration. 
         FIG. 9  shows a third embodiment of the pressure regulator of the present invention in partial cut-away, showing a controller connected to the pressure regulator for controlling pressure into the pressure chamber of the pressure regulator, the controller being in a third mode configuration. 
         FIG. 10  shows a fourth embodiment of the pressure regulator of the present invention in partial cut-away, showing a lever, cylinder, and spring assembly for controlling pressure, the lever being in a first position. 
         FIG. 11  shows a fourth embodiment of the pressure regulator of the present invention in partial cut-away, showing a lever, cylinder, and spring assembly for controlling pressure, the lever being in a second position. 
         FIG. 12  shows a fourth embodiment of the pressure regulator of the present invention in partial cut-away, showing a lever, cylinder, and spring assembly for controlling pressure, the lever being in a third position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     The present invention is directed toward a single-piston pressure regulator with incorporated shut off mechanism. The pressure regulator may be manufactured as a single integrated piece or may be manufactured as separate pieces that are connected together to form the pressure regulator assembly. For ease of describing the invention, the components of the pressure regulator may be described herein as being connected. It is understood, however, that the description of elements equally applies to the embodiment in which the components are individually pieces joined together to form the assembly. 
     With regards to  FIGS. 1-12 , the general configurations for various embodiments of the pressure regulator  2  of the present invention may be described. The pressure regulator  2  generally comprises a liquid flow inlet area  26  connected to a liquid flow outlet area  24  through a liquid flow chamber  6 . A sealing port  22  is positioned adjacent the liquid flow chamber  6  (either between the flow outlet area  24  and the liquid flow chamber  6 , as shown in  FIGS. 1-3 , or the flow inlet area  26  and liquid flow chamber  6 , as shown in  FIGS. 3-6 , depending on embodiment implemented). The pressure regulator  2  also includes a pressure chamber  8  and a piston  3 . The piston  3  preferably has a shaft  7  and a face plate  40 , the face plate  40  of the piston  3  being positioned inside the pressure chamber  8  such that the pressure chamber  8  is separated into a forward pressure chamber  8   b  and a rearward pressure chamber  8   a  by the plate. The shaft  7  of the piston  3  extends from the pressure chamber  8  into the liquid flow chamber  6 . A head cap  18  encloses the rearward pressure chamber  8   a,  and in some embodiments, a hand wheel assembly extends from outside the pressure chamber  8  into the pressure chamber  8 . These elements are generally enclosed in a housing (preferably a metal housing). 
     In one embodiment, the flow inlet area  26  is at a generally 45° angle to the liquid flow chamber  6 , as shown in  FIGS. 1-3 . Alternatively, the flow inlet area  26  may run parallel to the liquid flow area  6 , as shown in  FIGS. 3-6 . In yet another embodiment (not shown) the flow inlet area  26  may be substantially perpendicular to the liquid flow chamber  6 . It is also contemplated that the flow inlet area  26  may be positioned between the pressure chamber  8  of the regulator  2  and the flow outlet area  24  ( FIGS. 1-3 , wherein the pressure chamber  8  is on a first side of the inlet chamber  26  and liquid flow chamber  6  and the flow outlet area  24  is on the opposite side), or alternatively, that the flow outlet area  24  is positioned between the flow inlet flow area  26  and the pressure chamber  8  ( FIGS. 3-6 , wherein the pressure chamber  8  and flow inlet area  26  are on opposite sides of the liquid flow chamber  6  and flow outlet area  24 ). In any event, the functioning of the regulator  2  is substantially the same—a piston  3  moves within the regulator  2  to open and close the liquid flow chamber  6 , allowing varying degrees of liquid flow through the liquid flow chamber  6  and out through the outlet flow area  24  into, for example, a pump suction inlet  64 . It is understood that any other configuration is within the scope of the invention, and various such configurations may be required in order to fit within available space, particularly in tight-fitting applications such as on a firetruck with CAFS equipment. 
     A piston  3  is situated inside the regulator  2  and is fitted to slide longitudinally within the regulator  2  along an axis that extends along the centerline of the regulator  2 . The piston  3  includes a plate  40  and a shaft  7  extending from one side of the plate  40 . The piston  3  has a number of faces that are positioned in different areas of the regulator  2 : a forward face  41   b  of the plate  40 , a rearward face  41   a  of the plate  40 , and a forward face  4  on the shaft  7 . In one embodiment, the shaft  7  may also include a beveled or tapered edge  5  on its forward face  4 , as shown in  FIGS. 1-3 . These faces and beveled portion act as points on the piston  3  on which fluids (either the pressurized fluid in the pressure chamber  8  or the liquid in the liquid flow chamber  6 ) exert forces on the piston  3  causing the piston  3  to move within the regulator  2 . The piston  3  is positioned inside the regulator  2  such that the plate  40  of the piston  3  is positioned inside of the pressure chamber  8  and the shaft  7  of the piston extends from the pressure chamber  8  through a dividing wall  40  and into the liquid flow chamber  6 . Sealing elements  20  may be positioned between the piston shaft  7  and opening in the dividing wall  40  to prevent flow of fluid through the dividing wall  40  between the pressure chamber  8  and liquid flow chamber  6 . 
     As mentioned above, the plate  40  of the piston  3  has a forward face  41   b  and a rearward face  41   a.  In the preferred embodiment, the diameter of the plate  40  of the piston  3  is substantially close to the diameter of the pressure chamber  8  such that the side surfaces of the plate  40  substantially create a seal with the walls  16  of the pressure chamber  8 . Sealing elements  20  may be included between the side walls of the plate  40  and the walls  16  of the pressure chamber  8  to further facilitate sealing. These sealing elements  20  provide a fluid-tight seal, which allows the piston  3  to move along its longitudinal axis while preventing fluid from flowing between the outer surfaces of the plate  40  and the inner surface of the pressure chamber  8 . Thus, because the plate  40  of the piston  3  creates a seal with the inner walls  16  of the pressure chamber  8 , the pressure chamber  8  is effectively divided into two portions, a rearward pressure chamber  8   a  and a forward pressure chamber  8   b —one on either side of the plate  40  of the piston  3  such that the rearward face  41   a  of the plate  40  is positioned inside the rearward chamber  8   a  and the forward face  41   b  of the plate  40  is positioned inside the forward chamber  8   b.  As described above, in one embodiment the shaft  7  has a forward face  4  and an adjacent beveled edge  5 . The forward face  4  of the shaft  3  (and the adjacent beveled area  5 ) is situated inside the liquid flow chamber  6 . 
     The flow inlet area  26  is configured to receive a liquid from a pressurized liquid source (not shown). The source may be, for example, a water tank, or water that is mixed with a surfactant either in a tank, or in a line that feeds the water from the tank to flow inlet area  26 . The flow inlet area  26  is fluidically connected to the liquid flow chamber  6 , which separates the flow inlet area  26  from the flow outlet area  24 . A portion of the shaft  7  of the piston  3  is positioned inside the liquid flow chamber  6  and is configured to move within the liquid flow chamber  6  such that the regulator  2  moves between a fully opened position (as shown in  FIGS. 3 and 6 ) and a fully closed position (as shown in  FIGS. 1 and 4 ). The fully closed position is characterized as the piston  3  being in the most forward position such that the forward face  4  of the piston&#39;s shaft  7  creates a seal with the sealing port  22 , thereby preventing liquid flow through the liquid flow chamber  6 . The fully open position is characterized as the piston  3  being positioned as far rearward as possible, thereby allowing maximum liquid flow into the liquid flow chamber  6  from the inlet area  26  and out of the liquid flow chamber  6  through the outlet area  24 . The piston  3  may move to any position between the fully open position and fully closed position such that the forward face  4  of the shaft  7  of the piston  3  is at varying positions relative to the sealing port  22 . As the forward face  4  of the shaft  7  of the piston  3  moves toward or away from the sealing port  22 , varying amounts of liquid flow through the liquid flow chamber  6  is allowed, thereby regulating the liquid flow through the regulator  2 . 
     The liquid flow chamber  6  includes a sealing port  22  that works in conjunction with the piston  3  to seal the liquid flow chamber  6  and prohibit liquid flow through the liquid flow chamber  6 . In one embodiment, the sealing port  22  is positioned between the liquid flow chamber  6  and the flow outlet area  24  such that when the piston  3  moves to its most forward position, liquid may enter at least a portion of the liquid flow chamber  6  through the flow inlet area  26 , but cannot exit through the flow outlet area  24  because the sealing port  22  is closed by the piston  3  (as shown in  FIGS. 1-3 , wherein sealing port  22  is positioned between the liquid flow chamber  6  and flow outlet area  24 ). In an alternate embodiment, as shown in  FIGS. 3-6 , the sealing port  22  is positioned between the liquid flow chamber  6  and the flow inlet area  26  such that liquid is prohibited from entering the liquid flow chamber  6  entirely (and thus also prohibiting liquid from exiting the regulator through the flow outlet area  24  into the pump). In one embodiment of the pressure regulator  2  of the present invention, the sealing port  22  may incorporate a beveled sealing element to further facilitate sealing of the sealing port  22 , such that the beveled face  5  of the piston  3  fits into the beveled sealing element, thereby creating a better seal. In one embodiment, this sealing element may be a valve seat located at the sealing port  22 , the valve seat being manufactured integral to the regulator housing. As noted above, in one embodiment the pressure regulator  2  may comprise a number of separate pieces that are mechanically connected. In such an embodiment, the sealing element may be an outlet ring that is connected to the regulator housing after manufacture, the outlet ring serving as both the sealing port  22  and flow outlet area  24 . 
     As indicated, the piston  3  is configured to move within the regulator  2  between open and closed positions due to pressures exerted on the various piston faces by the liquid flowing through the liquid flow chamber  6  and by a pressurized fluid introduced into the pressure chamber  8 . In the preferred embodiment, a pressurized fluid source  44  is used to regulate the pressure of the fluid flowing into the pressure chamber  8 . While it is understood that various applications may be used (such as pneumatic or hydraulic), because the preferred embodiment utilizes pneumatic pressure, the invention will be described using a description of a pneumatic pressure application. In the preferred embodiment, the regulator  2  is fluidically connected to a pressurized air source  44 , preferably having two lines  54   a.    54   b  for transmitting air from the pressurized air source  44  into the pressure chamber  8  of the regulator  2 . One of the air supply lines  54   a  is preferably connected to the rearward pressure chamber  8   a  and the other air supply line  54   b  is connected to the forward pressure chamber  8   b,  such that pressurized air may be introduced into each chamber  8   a,    8   b  independently. A valve  78   a,    78   b  on each air supply line  54   a,    54   b  allows for the selective operation of each air supply line  54   a,    54   b  independently, allowing the operator to modify the amount of pressurized air introduced into each pressure chamber  8   a,    8   b.  Varying the pressure introduced into either chamber  8   a,    8   b  allows for the selective movement of the piston  3  within the regulator  2 , allowing more precise regulation of liquid flow through the regulator  2 . Further, the ability to introduce pressurized air on the forward face  41   b  of the piston plate  40  allows for a “dampening” effect on the movement of the piston  3 . It is understood that as the piston  3  moves between its open and closed positions, the area on which the liquid flowing into the liquid flow chamber  6  exerts force on the piston shaft  7  changes (as more or less of the forward face  4  of the shaft  7  of the piston  3  is now disposed to the liquid). Though this change is minimal, this coupled with the changes in the supply pressure of the liquid as flow increases, results in variation of pressure at the pump inlet  64 . While in most instances this does not present a problem, in foam applications, it does cause some variation in foam to water ratio. For this reason, the ability to variable introduce pressure into the forward pressure chamber  8   b  allows for the dampening or cushioning effect. The ability to vary the pressure on each side of the plate  40  allows for the resistance to opening or closing of the valve to be maintained in a balanced state during operation. For example, should the liquid flow pressure decrease during operation and the pressure in the rear pressure chamber  8   b  remain the same, without introduction of pressure into the forward pressure chamber  8   a,  the piston  3  would necessarily move toward a closed position. Introduction of pressure into the forward pressure chamber  8   b  can prohibit this undesired movement. 
     As noted above, in one embodiment of the pressure regulator  2  of the present invention, the pressure regulator  2  uses a wheel  28  to control the movement capabilities of the piston  3 . In one embodiment, a substantially circular hand wheel  28  may be implemented. It is understood that any variation of wheel shape may be used, so long as the wheel  28  may be used to rotate a threaded shaft  30  connected to the wheel  28 , thereby moving a plate  34  in a forward or rearward direction to change the area in which the piston  3  may move. The hand wheel  28  is connected to one end of the threaded shaft  30 , while the plate  34  is located at the other end of the threaded shaft  30 . As indicated above, a head cap  18  is connected to the rear pressure chamber  8   a  and this head cap  18  serves to enclose the rear pressure chamber  8   a.  This head cap  18  may be manufactured integral to the housing of the rear pressure chamber  8   a  or may be a separate piece positioned between the moveable plate  34  and the hand wheel  28  that is configured to be fitted, by welding, bolts, or other means to the end of the rear pressure chamber  8   a.  In either event, the head cap  18  is configured such that the threaded shaft  30  extends through the head cap  18  and into the rear pressure chamber  8   a.  The hand wheel  28  preferably remains on the exterior of the rear chamber  8   a  housing such that the wheel  28  can be accessed by the user during use of the regulator  2 . The rotation of the hand wheel  28  by the user in turn causes the threaded shaft  30  to rotate, thus causing the movable plate  34  to move forward or rearward in the rear pressure chamber  8   a.    
     In one embodiment, the threaded shaft  30  may extend from the hand wheel  28  into a hollow portion  10  of the piston  3 . This hollow portion  10  of the piston  3  is designed to receive the end of the threaded shaft  30 , but not to contact the threaded shaft  30  so that the piston  3  is not prohibited from sliding by the threaded shaft  30 . In one embodiment, guide pins  38  are used to prohibit the movable plate  34  from rotating as the threaded shaft is rotated  30 , thus allowing the plate  34  to only move forward or rearward depending on the rotation of the hand wheel  28 . The guide pins  38  are preferably threaded into the end cap  18  at one end with the other ends extending through the moveable plate  34 . In one embodiment, the guide pins  38  extend into hollow area  10  of the piston  3  to secure the piston  3  to the guide pins  38  while also allowing piston  3  to move freely toward and away from the sealing port  22  in order to control the flow of fluid in the fluid flow chamber  6 . The outer diameter of the moveable plate  34  is such that it will engage the rear face  41   a  of the piston  3  as the plate  34  moves forward, thus limiting the rearward movement of piston  3 . As the plate  34  continues to move into the rearward face  41   a  of the piston  3 , the plate  34  forces the piston  3  into the sealing port  22 , thereby preventing flow of water through the fluid flow chamber  6  altogether. 
     Thus, it may be seen that the hand wheel  28  provides a manual means to override the automatic pressure regulation of the regulator  2 . By turning hand wheel  28 , movable plate  34  may be moved forwardly or rearwardly depending upon the direction of rotation. Using right hand threads, turning hand wheel  28  clockwise would cause movable plate  34  to more forwardly, but the invention is not so limited. It may be seen that the position of movable plate  34  within the interior of the rear chamber  8   a  provides a stop to the maximum rearward movement of piston  3 , and thus provides a manual override function to the degree to which the valve may open under automatic operation. If hand wheel  28  is turned such that movable plate  34  is fully forward, then it presses the forward face  4  of the shaft  7  of the piston  3  (and the beveled edge area  5 ) fully against the sealing port  22 , thereby stopping the passage of liquid through fluid flow chamber  6  and out of the outlet area  24 , and therefore stopping all flow through the regulator  2 . Although the hand wheel  28  is shown as a manually controlled wheel in the illustrated implementation, various electronic, hydraulic, pneumatic, or other powered control means could be used to actuate the position of moveable plate  34 . 
     The structure of the regulator  2  having now been described, its operation may be described as follows. Generally speaking, a first pressurized liquid flows from a pressurized liquid source (not shown) into the liquid flow chamber  6  through the flow inlet area  26 . This flow of liquid exerts a pressure at the forward face  4  of the piston shaft  7 , which is positioned inside the liquid flow chamber  6 . In one embodiment, pressure is also exerted on the beveled portion  5  of the piston&#39;s shaft  7 . This exertion of pressure on the forward face  4  and beveled portion  5  of the shaft  7  moves the piston rearward into the pressure chamber  8  (i.e. moving toward the fully open position), which serves to open the valve to allow flow through the liquid flow chamber  6  and out through the flow outlet area  24 . 
     As the piston  3  moves into the pressure chamber  8 , the user may selectively introduce pressurized air (or another pressurized fluid) into the pressure chamber  8  through the pressurized air inlets  55   a,    55   b  located within the separate portions  8   a,    8   b  of the pressure chamber  8  and fluidically connected to the pressurized air supply  44  (or other pressurized fluid supply) through the supply lines  54   a,    54   b.  As pressurized air is introduced into the rearward pressure chamber  8   a  the pressure builds in the rear pressure chamber  8   a.  As the pressure in the rear pressure chamber  8   a  builds, the air exerts a force on the rear face  41   a  of the piston plate  40 . Once the pressure exerted on the rear face  41   a  of the piston plate  40  increases to a certain point (sufficient to overcome the force exerted by the liquid at the front face  4  of the piston shaft  3 ), the piston  3  is pushed back forward. The piston  3  may continue to move forward until the pressures at the rear face  41   a  of the piston plate  40  and at the front face  4  and beveled portion  5  of the piston shaft  7  equalize, thus creating a regulation of the pressure of fluid that flows out of the outlet flow area  24  of the regulator. The precise position at which the piston  3  reaches equilibrium may be modified by varying the areas of the forward parts of the piston shaft  3  (forward face  4  and beveled portion  5 ) proportionally to the area of the rear face  41   a  of the piston plate  40 . In one embodiment, the rearward face  41   a  of the piston plate  40  has a diameter of 6″ whereas the diameter of piston shaft  3  is 4 ½″ and the diameter of the beveled portion  5  is 3 ¾″. Because the area onto which fluid pressure may be asserted is greater at the rear of the piston  3  (i.e. rear face  41   a  of the plate  40 ) than the area at the front of the piston  3  (i.e. the face  4  of the shaft  7  and beveled portion  5  of the shaft  7 ), it may be seen that as pressure builds behind the rear face  41   a  of the piston plate  40  due to introduction of a pressurized fluid into the rear pressure chamber  8   a,  the pressure to force piston  3  rearward (and thereby regulate flow through the regulator  2 ) will increase. 
     To further overcome the pressure exerted at the rear face  41   a  of the plate  40  by the pressurized fluid introduced into the rear chamber  8   a,  the user may selectively introduce pressurized fluid into the forward pressure chamber  8   b  from the same pressurized fluid source  44  or from a different pressurized fluid source. The pressurized fluid may then exert a force on the forward face  41   b  of the plate  40  in a direction opposite the force exerted at the rear face  41   a  of the plate  40 . This pressure exerted on the forward face  41   b  of the piston plate  40  may work with the pressure exerted on the shaft  7  by the fluid flowing in the fluid flow chamber  6  to balance the pressure exerted in the rear pressure chamber  8   a.  The pressure introduced on either side  8   a,    8   b  of the pressure chamber  8  can be selectively controlled such that flow regulation of the fluid through the fluid flow chamber  6  can be selectively regulated as desired. 
     In one embodiment, the degree of pressurized fluid introduced into the various sides  8   a,    8   b  of the pressure chamber  8  may be selectively (or automatically) controlled by a controller  80  in communication with a microprocessor. The use of a microprocessor capable of changing rates of the pressurized fluid source several times a second allows for a constant adjustment regulation rate through the regulator  2 , allowing for appropriate flow through the regulator  2  within a very tight window. In one embodiment, a pressure switch or transducer may  46  be located in the outlet flow area  24  to provide a signal to the controller  80  (or user, if manual control of pressure is implemented) to modify the pressure introduced into the various sides  8   a,    8   b  of the pressure chamber such that the pressures can be balanced at the desired flow rate, as shown in  FIGS. 7-9 . 
     In various embodiments, the pressurized air supply lines  54   a,    54   b  may each include a valve  78   a,    78   b  for selective operation of the air supply line  54   a,    54   b,  allowing the user to selectively control the introduction of pressurized air into each pressure chamber  8   a,    8   b  of the regulator  2 . The valves  78   a,    78   b  may also include vents  42   a ,  42   b,  allowing pressurized air to be released through the valve  78   a,    78   b,  which may, for example, be useful for bleeding air from the supply hose or releasing air from the portion  8   a,    8   b  of the pressure chamber  8  fluidically connected to that particular air supply line  54   a,    54   b  and valve  78   a,    78   b.  By independently controlling each air supply line  54   a,    54   b  and valve  78   a,    78   b  to either its supply position (wherein pressurized air is introduced through the line into the pressure chamber  8   a,    8   b ) or its vent position (wherein pressurized air is vented from the pressure chamber  8   a,    8   b  through the air supply line  54   a,    54   b  and valve  78   a,    78   b ), various modes of operation of the regulator  2  may be selectively achieved as desired by the user. 
     For example, in a first mode configuration, as shown in  FIGS. 1, 4, and 7 , the regulator  2  may be moved toward the closed position by selectively positioning the valve  78   a  associated with the rear pressure chamber  8   a  supply line  54   a  to the supply position and selectively positioning the valve  78   b  associated with the forward pressure chamber  8   b  supply line  54   b  in the vent position (such as the forward pressure chamber  8   b  vents through the supply line  54   b  and out of the vent  42   b  in the valve  78   b ). This first mode configuration allows the piston  3  to move to the closed position as the pressure in the rear chamber  8   a  builds and overcomes the pressure exerted by the liquid flowing into the regulator  2  on the shaft  7  of the piston  3  (as no pressure is applied in forward pressure chamber  8   b  to dampen or overcome the pressure in rearward pressure chamber  8   a ). In a second mode configuration, which is shown in  FIGS. 3, 6 and 8 , the piston may be moved toward the open position to allow for full flow of liquid out of the regulator  2  by selectively positioning the valve  78   a  associated with the rear pressure chamber  8   a  in the vent position and positioning the valve  78   b  associated with the forward pressure chamber  8   b  in the supply position. In this second mode configuration, pressure in the forward pressure chamber  8   b  builds and acts against the forward face  41   b  of the piston plate  40 , pushing the piston  3  rearward in the regulator  2  and allowing fully flow of liquid through the liquid flow chamber  6  because there is no pressure in rear pressure chamber  8   a  to overcome the pressure applied in forward pressure chamber  8   b.    
     In a third mode configuration, as shown generally in  FIGS. 2 and 5 , and more particularly in  FIG. 9 , transducers  46 ,  48  positioned at various points may communicate with a controller  80  to selectively modify the positioning of the valves  78   a,    78   b  on each of the rear  54   a  and forward  54   b  pressure supply lines based on the pressure readings at the various transducers  46 ,  48 . For example, as shown in  FIG. 9 , a transducer  48  positioned at the rear pressure chamber supply line  54   a  relays the pressure in the rear pressure chamber  8   a  to the controller  80  and a transducer  46  positioned at the pump inlet  64  (i.e. at the flow outlet area  24  of the regulator  2 ) relays the pressure at the flow outlet area  24  and pump inlet  64  to the controller  80 . If a certain pressure is desired in the rear pressure chamber  8   a,  the controller  80  may react to pressure readings outside of the desired range. For example, if a pressure between 40-45 psi is desired in the rear pressure chamber  8   a,  the controller  80  may, upon a reading of less than 40 psi at transducer  48 , direct pressurized air into the rear chamber  8   a  and, upon a reading of greater than  45  at transducer  48 , direct pressure from rear pressure chamber  8   a  to vent through the air line  54   a,  valve  78   a,  and vent  42   a  connected to the rear chamber  8   a . Likewise, when a higher than desired pressure is recorded by the transducer  46  at the pump inlet  64 , the controller  80  directs the pressure to increase in the rear pressure chamber  8   a  to move the valve toward the closed position. Alternatively, based on the pressure recorded by the transducer  46  at the flow outlet area  24 , the controller  80  may direct the valve  78   b  on the line  54   b  connected to the forward pressure chamber  8   b  to introduce pressure or vent pressure from the forward pressure chamber  8   b.  It is contemplated that in the event of loss of air pressure or the failure of the controller  80 , a manual valve may be implemented to manually vent air from the pressure chamber  8 . At this point, pressure from liquid source exerting on the shaft  7  of the piston  3  may be used to move the piston  3  to the open position, while the hand wheel  28  may be used to dose move the piston  3  to the closed position or otherwise regulate the piston  3  movement. With regard to the transducer  46  placed at the flow outlet area  24 , it is contemplated that locating the transducer  46  as close to the pump impellor as possible (as opposed to right at the start of the flow outlet area  24 ) allows for a more accurate regulation of pressure. 
     In one embodiment, the valve  78   b  on the forward pressure chamber supply line  54   b  is controlled by a cylinder  88 , lever  86 , and spring  90  assembly, as shown in FIGS.  10 - 12 . The cylinder  88  comprises a piston that is inside a chamber fluidically connected to the flow outlet area  24  (i.e. the pump inlet area  64 ), such that change in pressure at the flow outlet area/pump inlet area  24 / 64  modifies the valve  78   b  based on movement of the cylinder  88  and lever  86  of the valve controlling assembly. The cylinder  88  and lever  86  move in various directions depending on the pressure exerted on the cylinder  88  by the liquid moving through a fluidic line  92  to the cylinder  88  from the pump inlet area  64 . For example, as shown in  FIG. 10 , when the pressure of the fluid is too low to overcome the compression force of the spring  90 , the lever is in an upward position, thus allowing the pressurized air to flow into the forward pressure chamber  8   a  of the regulator  2  through the valve  78   b  and supply line  54   b.  Should the pressure at the pump inlet  64  rise to a certain point such that it forces the cylinder  88  to compress, the lever  86  will be forced to move to a downward position, allowing for the venting of air pressure from the forward pressure chamber  8   a  through the valve  78   b  and vent  42   b,  as shown in  FIG. 11 . In either case, when the pressures balance, the lever  86  moves to a neutral position, as shown in  FIG. 12 , keeping the pressure steady until a pressure change causes movement of the lever  86  to occur to one of the supply or vent positions of the lever shown in  FIGS. 10-11 . Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, a limited number of the exemplary methods and materials are described herein. It will be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. 
     All terms used herein should be interpreted in the broadest possible manner consistent with the context. When a grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included in the disclosure. All references cited herein are hereby incorporated by reference to the extent that there is no inconsistency with the disclosure of this specification. If a range is expressed herein, such range is intended to encompass and disclose all sub-ranges within that range and all particular points within that range. 
     The present invention has been described with reference to certain embodiment(s) that are intended to be exemplary only and not limiting to the full scope of the present invention as set forth in the following claims.