Abstract:
A booster pilot valve operable at ultra low power levels is provided. The booster valve includes a moveable spool capable of directing a fluid flow to at least two different paths. The booster valve may be coupled to a piezotronic three-way valve, which controls the movement of the spool by redirecting a main fluid flow along different paths to create a force on the spool. The piezotronic valve is capable of actuation at very low power levels such as might be provided by a Profibus PA or other Bus system.

Description:
RELATION TO COPENDING APPLICATIONS  
       [0001]    This Non-provisional Application claims the benefit of the Provisional Application No. 60/192,119 filed Mar. 24, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates generally to valve actuating methods and apparatus and, more particularly, to booster pilot valves.  
         BACKGROUND AND SUMMARY OF THE INVENTION  
         [0003]    In recent years, industrial facilities, such as pharmaceutical or petrochemical plants, employ low-energy Bus systems to operate and control various processes. The low-energy Bus systems operate with currents ranging from 1.5 to 10 mA at an input voltage of 6 to 30 volts. The low-energy Bus systems consume less power than previously used operating and control systems. The use of low-energy Bus systems may reduce the overall operating expenses of the plants, among other advantages.  
           [0004]    With the introduction of low-energy Bus systems has also come a demand for valves that operate with the limited power supply of the Bus system. Large valves typically require a considerable amount of power to open and close, more power than may be available through the low-energy Bus system. Consequently, it has become a common practice to mount an air-powered cylinder on or near a large valve to actuate it. The air cylinder is often actuated by a solenoid or a pilot valve that is in communication with the air cylinder. The pilot valve requires much less power than conventional valve actuators. Therefore, it is desirable to design a pilot valve that operates at the extremely low power levels of low-energy Bus systems to actuate a larger valve. In addition, it is desirable that the pilot valve be compatible with a particular Bus system being used in a plant.  
           [0005]    The present invention is directed to providing a booster pilot valve operating at very low power levels to actuate a larger valve.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with one aspect of the present invention, a booster pilot valve includes a body and a hydraulic member. The body defines a fluid chamber. The hydraulic member is disposed in the fluid chamber and is movable by a pressurized flow between a first and a second position. The hydraulic member in the first position permits a cylinder port to communicate with a first ancillary port. The hydraulic member in the second position permits the pressurized flow to communicate with the cylinder port. In a further embodiment, the booster pilot valve includes a secondary device operable to direct the pressurized flow.  
           [0007]    In accordance with another aspect of the present invention, a booster pilot valve includes a body and a spool. The body defines a fluid chamber having a main port and an outlet port. The spool is disposed within the fluid chamber and is movable by a pressurized flow between a closed position and an opened position. The spool in the closed position permits a secondary flow form a cylinder port to communicate with a first ancillary port. The spool in the opened position permits the pressurized flow from the main port to communication with the cylinder port. In a further embodiment, the booster pilot valve includes a secondary valve communicating with the outlet port of the body. The secondary valve is operable to direct the pressurized flow entering the main port to move the spool to the closed or opened position. The secondary valve may include a three-way valve or may include a piezotronic valve.  
           [0008]    In accordance with yet another aspect of the present invention, a booster pilot valve includes a body and a hydraulic member. The body defines a fluid chamber and includes a main port and a stem. The main port is defined in a first end of the fluid chamber, and the stem protrudes into the fluid chamber from a second end. The stem defines an outlet port aligned with the main port. The hydraulic member is disposed in the fluid chamber and is movable between opened and closed positions within the fluid chamber. The hydraulic member includes first and second surfaces and a fluid passageway. The first surface is adjacent to the first end of the fluid chamber. The second surface is adjacent to the second end of the fluid chamber. The fluid passageway is defined in the hydraulic member and extends from the first surface to the second surface. The stem is partially disposed within the fluid passageway so that the fluid passageway communicates the main port with the outlet port. The hydraulic member in the opened position permits fluid communication of the main port with a cylinder port. The hydraulic member in the closed position permits fluid communication between the cylinder port and a first ancillary port.  
           [0009]    In accordance with a further aspect of the present invention, a method of operating a valve element with a hydraulic device includes: supplying a pressurized flow into the hydraulic device; directing the pressurized flow to the valve element by selectively concentrating the pressurized flow to move the hydraulic device to an opened position; and directing a secondary flow from the valve element to an ancillary port in the hydraulic device by selectively concentrating the pressurized flow to move the hydraulic device to a closed position.  
           [0010]    The foregoing summary is not intended to summarize each potential embodiment, or every aspect of the invention disclosed herein, but merely to summarize the appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The present invention, including a preferred embodiment and other aspects, will be best understood with reference to the detailed description of specific embodiments of the invention, which follows, when read in conjunction with the accompanying drawings, in which:  
         [0012]    [0012]FIG. 1 illustrates a side view of a booster pilot valve in accordance with one aspect of the present invention.  
         [0013]    [0013]FIG. 2 illustrates a cross-sectional, detailed view of the booster pilot valve according to FIG. 1 taken along line A-A.  
         [0014]    [0014]FIG. 3A schematically illustrates the booster pilot valve in a first or closed position in relation to a main valve;  
         [0015]    [0015]FIG. 3B schematically illustrates the booster pilot valve in a second or opened position in relation to the main valve;  
         [0016]    [0016]FIG. 4 illustrates a cross-sectional view of the booster pilot valve according to FIG. 1 taken along line B-B.  
         [0017]    [0017]FIG. 5 illustrates a cross-sectional view of the booster pilot valve according to FIG. 1 taken along line C-C.  
         [0018]    [0018]FIG. 6 illustrates a cross-sectional view of the booster pilot valve according to FIG. 1 taken along line D-D.  
         [0019]    [0019]FIG. 7 illustrates a top view of the booster pilot valve according to the present invention;  
         [0020]    [0020]FIG. 8 illustrates a bottom view of the booster pilot valve according to the present invention; and  
         [0021]    [0021]FIG. 9 illustrates a perspective view of the booster pilot valve connected to a larger valve.  
         [0022]    While the invention described herein is susceptible to various modifications and alternative forms, only specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not to be limited to or restricted by the particular forms disclosed herein.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]    Referring to FIG. 1, a side view of a booster pilot valve  10  illustrates one embodiment of the present invention. The booster pilot valve  10  includes a primary valve  20  and a secondary device  30 . The primary valve  20  facilitates connection with a main valve (not shown) and includes an adapter  100  and a body  140 . The adapter  100  and the body portion  140  may comprise stainless steel or other materials. The body portion  140  may also be adapted to connect directly to a fluid source such as pressurized air.  
         [0024]    The body  140  connects to the adapter  100  at a first end  141 . In the present embodiment, the diameter of body  140  is smaller than the diameter of adapter  100  at the first end  141 . Located around the periphery of primary valve  20  are an adapter recess  112  and a body recess  142 . Adapter recess  112  circumscribes the adapter  100 , and body recess  142  circumscribes the body  140 . Adapter recess  112  and body recess  142  receive seals  190  and  191 , respectively. The seals  190  and  191 , which are preferably O-ring seals, seal an annulus formed between primary valve  20  and a main valve (not shown) when the two are connected.  
         [0025]    The secondary device  30  is attached to the primary valve  20 . The secondary device  30  includes a secondary valve  40 , which is preferably a three-way valve. More particularly, the secondary valve  40  may preferably be a three-way piezotronic valve. In order to operate the booster pilot valve  10 , the piezotronic valve  40  must have compatible electronics (not shown) to accept signals from an operating platform or a network Bus (not shown). In one embodiment, the booster pilot valve  10  may be provided with a Profibus PA operator, but other operators compatible with other Bus systems, including, but not limited to, Profibus DP, Fieldbus Foundation and DeviceNet may also be used. The operation of the primary valve  20 , however, may not change with any alterations in electronics. With the benefit of this disclosure, one of skill in the art will recognize that the piezo-operated three-way valve  40  may be obtained from the Automated Switch Company (ASCO), but other three-way valves may also be used.  
         [0026]    The piezotronic valve  40  advantageously requires very little power to operate, on the order of 100 mW with currents in the range of approximately 1.5 to 10 mA, which can be provided by the low-energy Bus system. The piezotronic valve  40  is shrouded by a cover  32 . An electrical connector  34  extends from cover  32  for connection to a power source or the Bus system. The piezotronic valve  40  and any additional electronics may also be encapsulated in epoxy within the cover  32  for protection from the environment.  
         [0027]    Referring to FIG. 2, a cross-section of the primary valve  20  of FIG. 1 taken along line A-A further illustrates the present invention. As before, the primary valve  20  includes the body  140  connected to the adapter  100 . The primary valve  20  further includes a hydraulic member or spool  160 . For simplicity, the fasteners and apertures for connecting the adapter  100 , the body  140  and the secondary device  30  have been omitted from FIG. 2.  
         [0028]    The adapter  100  includes a first adapter portion  110  and a second adapter portion  120 . The first adapter portion  110  connects to the secondary device  30 , and the second adapter portion  120  connects to the body  140 . The first adapter portion  110  includes the adapter recess  112  circumscribing its periphery. The first adapter portion  110  further includes a protrusion or stem  114 , an outlet port  116  and a fluid passageway  118 . The protrusion  114  projects from the first adapter portion  110  into a first internal bore  122  in the second adapter portion  120 . The outlet port  116  extends from a distal end of the protrusion  114  to an opening  117 , which communicates with the secondary device  30  and more specifically with the piezotronic valve  40 .  
         [0029]    The second adapter portion  120  is connected to the first adapter portion  110 . The second adapter portion  120  defines the first internal bore  122  that accommodates the protrusion or stem  114  of the first adapter portion  110 . The first internal bore  122  has a greater diameter than that of the protrusion  114  so that a second plenum  132  is formed therebetween. The fluid passageway  118  is shown with dashed line to illustrate fluid communication between the piezotronic valve  40  and the second plenum  132 . The actual location of the fluid passageway  118  may be on a dihedral plane to the cross-sectional plane of FIG. 2. Furthermore, additional ancillary ports (not shown) may communicate the piezotronic valve  40  with the second plenum  132 . The second adapter portion  120  further includes an annular extension  124  extending therefrom. The annular extension  124  includes a second internal bore  126 , which communicates with the first internal bore  122  but has a lesser diameter.  
         [0030]    The body  140  includes the body recess  124  and further includes a main port  144  and cylinder ports  146   a - b.  The body  140  defines an internal bore having a first bore portion  150 , a first shoulder  152 , a second bore portion  154 , and a second shoulder  156 . The body  140  is connected to the second adapter portion  120  so that the annular extension  124  is disposed in the first bore portion  150 . A decrease in diameter at the first shoulder  152  forms the second bore portion  154  that communicates with the first bore portion  150 . The main port  144  communicates with the second bore portion  154  at the second shoulder  156 , and the cylinder ports  146   a - b  communicate with the first bore portion  150  at the first shoulder  152 .  
         [0031]    The bores  150  and  152  of the body  140  and the internal bores  122  and  124  of the adapter  100  define a fluid chamber within the primary valve  20 . The hydraulic member or spool  160 , which may be constructed of stainless steel or other materials, is disposed within the fluid chamber of the primary valve  20  and is movable therein. Specifically, the spool  160  is partially disposed and movable within internal bore  122  of the second adapter portion  120  and partially disposed and movable within the internal bore  126  of the annular extension  124 . The spool  160  is also partially disposed and movable within the second bore portion  154  of the body  140 .  
         [0032]    The spool  160  includes a first surface  164 , a second surface  168  and a fluid passageway  170 . A first end  162  of the spool  160  exhibits the first surface  164  adjacent to the shoulder  156  of the fluid chamber. A first plenum  130  of the fluid chamber is defined between the first surface  164  and the shoulder  156 . A second end  166  of the spool  160  exhibits the second surface  168  within the fluid chamber. The second plenum  132  is further defined between the second surface  168  and the portion of the fluid chamber in the adapter  100 .  
         [0033]    In the present embodiment, the second surface  168  exhibits a greater surface area than the first surface  164 . The greater surface area of the second surface  168  results in part from an increasing diameter of the spool  160 . The diameter of the spool  160  increases at a shoulder  161  to approximately match the internal bore  126  of the annular extension  124 . The spool  160  also exhibits another increase in diameter at a shoulder  163  so that the second end  164  approximately matches the internal bore  122  of the first adapter portion  110 .  
         [0034]    The fluid passageway  170  provides for fluid communication through the interior of the spool  160  and extends from the first surface  164  to the second surface  168 . The protrusion or stem  114  of the first adapter portion  110  is partially disposed within the fluid passageway  170 . A filter (not shown) may be disposed in the passageway  170 . The filter may be commercially available and may filter particles, for example, to approximately fifty microns. The fluid passageway  170  communicates the main port  144  with the outlet port  116  of the primary valve  20 . Thus, fluid (not shown) may communicate between the main port  144  and the three-way piezotronic valve  40 .  
         [0035]    The primary valve  20  contains a plurality of seals used for both the connection and engagement of the components. Referring concurrently to FIGS. 2, 5 and  6 , the adapter  100  includes the seals  192 ,  193 ,  195  and  196 , which are preferably O-ring seals. The first adapter seal  192  seals the connection of the first adapter portion  110  to the second adapter portion  120 . The second adapter seal  193  seals engagement of the protrusion  114  with the fluid passageway  170  of the spool  160 . The third adapter seal  195  seals the connection between the adapter  100  and the body  140 . The fourth adapter seal  196  seals connection of the annular extension  124  with the first internal bore  150  of the body  140 .  
         [0036]    The hydraulic member or spool  160  includes a plurality of seals for the engagement of the spool  160  with the fluid chamber of the primary valve  20 . The spool  160  includes a seal  194 , which is preferably a U-cup seal, and includes the seals  197  and  198 , which are preferably O-ring seals. The U-cup seal  194 , disposed in an annular recess  172 , seals engagement of the spool  160  with the internal bore  122  of the second adapter portion  120 . The U-cup seal  194  seals off fluid contained in the second plenum  132 .  
         [0037]    The seal  197  seals the engagement between the spool  160  and the annular extension  124  when the spool  160  is appropriately positioned within the fluid chamber. With the spool  160  in a first position as shown in FIGS. 2 and 3A, the seal  197  lacks engagement with the internal bore  126 . Fluid communication is thus permitted from the cylinder ports  146   a - b  to a first annulus  200  between the spool  160  and the adapter extension  124 . When the spool  160  is moved to a second position as shown in FIG. 3B, the seal  197  engages the internal bore  126  of the annular extension  124  and seals the fluid communication of the cylinder ports  146   a - b  with the first annulus  200 . The seal  198  seals the engagement of the spool  160  with the second bore portion  154  of the body  140  when the spool  160  is appropriately positioned within the fluid chamber. Further details regarding the engagement of the seals in the primary valve  20  are provided below with reference to FIGS. 3A and 3B.  
         [0038]    In a general description of the operation of the primary valve  20 , pressurized fluid (not shown) may enter the fluid chamber of the primary valve  20  though the main port  144 . The pressurized fluid may concentrate in the first plenum  130 . With the application of pressure from the pressurized fluid to the first surface  164 , a first force may be produced that urges the spool  160  to move within the fluid chamber and distance from the shoulder  156 . The pressurized fluid may also pass through the fluid passageway  170  and into the piezotronic valve  40  via the outlet port  116 . The pressurized fluid may be directed by the piezotronic valve  40  to the second plenum  132  via the fluid passageway  118 . With the application of pressure from the pressurized fluid to the second surface  168 , a second force may be produced that urges the spool  160  to move within the fluid chamber and distance from the first adapter portion  110 . Fluid in the second plenum  132  may be further vented by communicating the piezotronic valve  40  with the adapter recess  112  via a first ancillary port  119  at the adapter recess  112 .  
         [0039]    Moreover, when the spool is in the second or closed position as shown in FIG. 2, a second fluid flow (not shown) may communicate from the cylinder ports  146   a - b  to the first annulus  200 , to an opening  202 , to a second annulus  204 , to a second ancillary port  206  and to the body recess  142 . The first annulus  200  is formed between the spool  160  and the annular extension  124 . The opening  202  is defined in the annular extension  124  of the second adapter portion  120 . The opening  202  communicates the first annulus  200  with the second annulus  204 . The second annulus  204  is formed between the annular extension  124  and the first internal bore  150  of the body  140 . Only one opening  202  is shown, but a number of similar openings may be formed circumscribing the annular extension  124 . The second ancillary port  206  communicates the second annulus  204  with the body recess  142 , where the second fluid may be vented. Further details regarding the movement of the spool  160 , the flow of fluid and the operation of the booster pilot valve  10  are provided below with reference to FIGS. 3A and 3B.  
         [0040]    Referring now to FIGS.  3 A- 3 B, the operation of the booster pilot valve  10  is schematically illustrated. As before, the booster pilot valve  10  includes the primary valve  20  connected to the secondary device  30 . The primary valve  20  includes the adapter  100 , the body  140  and the movable spool  160  as described above. The secondary device  30  includes a secondary valve  40 , which is shown here schematically. The secondary valve  40  is preferably a three-way valve requiring low power levels to operate, such as the piezotronic valve as discussed above.  
         [0041]    In some embodiments, the booster pilot valve  10  may be used in series with at least one other pilot operated valve, such as the main valve  300  of FIGS.  3 A- 3 B. The booster pilot valve  10  may be capable of operating at very low power levels, but may not be able to provide an adequate flow rate of pressurized fluid to actuate a large valve in a reasonable time period. Therefore, the booster pilot valve  10  may only actuate another pilot operated valve, which may in turn directly actuate a large valve or in some cases may actuate yet another pilot operated valve. One advantage of the booster pilot valve  10 , however, is that it can operate at even the lowest Bus power levels, and thus begin a “stepping up” process to other pilot valves. The other pilot valve can eventually provide the necessary flow rate of pressurized fluid to ultimately operate the large valve. In other embodiments, the booster pilot valve  10  may be the only pilot valve used.  
         [0042]    The primary valve  20  connects to a main valve  300 . The main valve  300  communicates a pressurized working fluid PF to the primary valve  20  via a main line  302 . The pressured fluid PF represents a main flow ultimately intended to operate a large-valve actuator (not shown) or other pilot valve, such as main valve  300 . Conventional pilot valves use flow that is controlled by or flows through only the pilot valve itself. Advantageously, the booster pilot valve  10  of the present invention uses the pressurized flow PF to also influence the orientation of the spool  160 , which in turn redirects the path of pressurized fluid PF in the manner described below.  
         [0043]    The main valve  300  also communicates a second fluid CF from a cylinder (not shown) via cylinder lines  304   a - b.  The cylinder lines  304   a - b  communication the cylinder fluid CF between the cylinder and the booster pilot valve  10 . The cylinder may also be in communication with main valve  300  or other valves, and the cylinder may be, but is not limited to, a reservoir used to open/close another valve or to extend/retract a piston. The cylinder fluid CF may come from a closing cylinder (not shown) for the piloted valve  300  or from an actuator volume (not shown) that is being exhausted.  
         [0044]    Referring to FIG. 3A, the pressurized fluid PF is constantly supplied from the main valve  300 . The pressurized fluid PF enters the booster pilot valve  10  through the main port  144  and is permitted to concentrate within the first plenum  130  between the first surface  164  and the shoulder  156 . The pressure of the fluid PF is transmitted to the lower surface  164  of the spool  160 . Consequently, the pressurized fluid PF acting against the area of the lower surface  164  creates a first force F 1  on the spool  160 .  
         [0045]    The pressurized fluid PF is also permitted to pass through the fluid passageway  170  to the piezotronic valve  40  via the outlet port  116 . In FIG. 3A, the piezotronic valve  40  is de-energized and communicates the pressurized fluid PF from the outlet port  116  to the second plenum  132  via the fluid passageway  118 . The pressurized fluid PF is permitted to concentrate in the second plenum  132  and apply pressure to the second surface  168 . Consequently, a second force F 2  is produced on the spool  160  that opposes the first force F 1 .  
         [0046]    The area of the second surface  168  is preferably greater than the area of the first surface  164 . Therefore, the second force F 2  on the spool  160  is larger than the first force F 1 . The force differential (F 2 -F 1 ) tends to urge the spool  160  to a first or closed position illustrated in FIG. 3A when the piezotronic valve  40  is de-energized. Designing the areas of the first and second surfaces  164 ,  168  to urge the spool  160  to the first or closed position with the pressurized fluid PF and to overcome frictional forces is well within the ordinary skill of one in the art.  
         [0047]    With the spool  160  in the first or closed position, the seal  198  seals the fluid communication of the main port  144  from the cylinder ports  146   a - b.  The seal  197  lacks sealed engagement with the annular extension  124  of the adapter  100 . Consequently, the cylinder ports  146   a - b  are in fluid communication with the first annulus  200  between the spool  160  and the adapter  100 , and the cylinder fluid CF is permitted to flow from the cylinder ports  146   a - b  to the first annulus  200 . From the first annulus  200 , the cylinder fluid CF is permitted to flow through the opening  202  in the adapter extension  124  and into the second annulus  204  created between the adapter extension  124  and the body  140 . Finally, the cylinder fluid CF may vent to the atmospheric pressure through the second ancillary port  206  in the body recess  142 . Thus, by de-energizing the three-way piezotronic valve  40 , the spool  160  of the booster pilot valve  10  may be moved to the first or closed position with the pressurized fluid PF and may vent the cylinder fluid CF when the cylinder closes.  
         [0048]    Referring now to FIG. 3B, the path of the pressurized fluid PF within the booster pilot valve  10  has been altered to actuate the main valve  300  or some other valve for which main valve  300  is a pilot. As schematically illustrated, the piezotronic valve  40  is energized. The flow of pressurized fluid PF is restricted at the outlet port  116  by the piezotronic valve  40 , and the pressurized fluid PF is permitted to concentrate in the fluid chamber of the primary valve  20 . In addition, a new flow path is created by the three-way piezotronic valve  40  between the fluid passageway  118  and the first ancillary port  119 . The first ancillary port  119  leads to atmospheric pressure at the adapter recess  112 , enabling any pressurized fluid PF trapped in the second plenum  132  to escape.  
         [0049]    With the fluid passageway  118  in fluid communication with the first ancillary port  119 , the force on the second surface  168  subsides and only the Force F 1  on the first surface  164  predominates. Consequently, the Force F 1  urges the spool  160  into a second or opened position as shown in FIG. 3B. As the spool  160  moves within the fluid chamber, the seal  198  disengages the second bore portion  154  of the body  140 , and the seal  197  engages the internal bore  126  of the adapter extension  124 . A gap  220  is created between the spool  160  and the body  140 , which facilitates fluid communication of the pressurized fluid PF from the main port  144  to the cylinder ports  146   a - b.    
         [0050]    The pressurized fluid PF is permitted to flow through the gap  220  to the cylinder ports  146   a - b.  The pressurized fluid PF may further act on a pressure area  210  to drive the spool  160  the remaining stroke within the fluid chamber. The pressurized fluid PF is then directed out of the cylinder ports  146   a - b,  through the cylinder lines  304   a - b  in the main valve  300  and to the cylinder. The pressurized fluid PF may provide working pressure to actuate the main valve  300  that may be in communication with the cylinder. Thus, by energizing the three-way piezotronic valve  40 , the spool  160  of the booster pilot valve  10  may be moved to the second or opened position with the pressurized fluid PF and may actuate another larger valve.  
         [0051]    Referring now to FIGS.  4 - 9 , the embodiment of the booster pilot valve  10  is illustrated in a number of principle views. In the discussion that follows and for the sake of brevity, only certain features are described for each view. The same reference numerals are used in the FIGS.  4 - 9  to represent the same components in each view.  
         [0052]    In FIGS.  4 - 6 , the embodiment of the booster pilot valve  10  is illustrated in various cross-sections. FIG. 4 illustrates a cross-sectional view of the booster pilot valve according to FIG. 1 taken along line B-B. FIG. 5 illustrates a cross-sectional view of the booster pilot valve  10  according to FIG. 1 taken along line C-C. FIG. 6 illustrates a cross-sectional view of the booster pilot valve  10  according to FIG. 1 taken along line D-D. In FIGS.  7 - 9 , the embodiment of the booster pilot valve  10  is illustrated in a top view, a bottom view and a perspective view respectively.  
         [0053]    The secondary device  30  may include a push button activation system. The system may include a manual push button  36 , a spring  38 , and a gasket  41 . The manual push button  36  may be included on the cover  32  to activate the piezotronic valve  40 . The spring  38  returns the push button  36  to the deactivated position shown in the figures. The button  36  includes stems  37  to guide the movement of the button  36  within the cover  32 . The gasket  41  may be provided between the piezotronic valve  40  and the button  36 . Bolts  44  may attach the piezotronic  42  to the primary valve  20 . With the benefit of this disclosure, it will be understood by one of skill in the art that the push button activation system may be omitted.  
         [0054]    Particularly illustrated in FIGS. 5 and 6, the seals  190 - 198  as described in FIG. 2 are illustrated at differing points of cross-section than illustrated in FIG. 2. The cylinder port  146   b  is shown in cross-section communicating with the first shoulder  152 . Additionally, the opening  202  defines a radial bore in the annular extension  124 . The opening  202  communicates fluid from the first annulus  200  formed between the spool  160  and adapter extension  124  to the second annulus  204  formed between the adapter extension  124  and the body  140  as described above.  
         [0055]    In the bottom view of FIG. 8, the location of the main port  144  and cylinder ports  146   a - b  are illustrated in the bottom of the body  140 . Also, the PC board  31  holding the piezotronic valve (not shown) and additional electronics (not shown) is visible within the cover  32 . Particularly illustrated in FIG. 9, the booster pilot valve  10  is shown connected to a larger valve  310 . The booster pilot valve  10  may pilot the larger valve  310 : however; it will be understood by one of skill in the art with the benefit of this disclosure that booster pilot valve  10  is not limited to piloting the larger valve  310 , but may pilot other valves as well.  
         [0056]    While the invention has been described with reference to the preferred embodiments, obvious modifications and alterations are possible by those skilled in the related art. Therefore, it is intended that the invention include all such modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.