Abstract:
Methods for controlling flow are described herein that include a valve assembly provided and operated to control the flow from a first conduit to a second conduit. The valve assembly includes an actuator housing enclosing an actuator piston and defining a counter-biasing chamber and a first control chamber on the same side of the actuator piston, and a first pressure control port in fluid communication with the first control chamber. A valve is connected to the actuator piston and a bore passes through both the actuator piston and the valve thereby placing a face of the valve in fluid communication with the counter-biasing chamber. The actuator piston includes a first substrate area that defines a portion of the counter-biasing chamber and a second substrate area that defines a portion of the first control chamber where the surface area of the first substrate area is less than the surface area of the valve face.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 12/717,130, filed Mar. 13, 2010. 
    
    
     FIELD 
     The embodiments described herein relate to the mechanical arts. More specifically, the present invention relates to valve actuator assemblies. 
     BACKGROUND 
     It can be appreciated that valve actuator assemblies have been in use for years. These assemblies control the flow of liquids or gasses in a variety of industrial and mechanical settings. Typically, valve actuator assemblies comprises one of three main types of design: those comprising diaphragm actuators, actuator pistons, or electromechanical actuators. These assemblies are typically used in controlling one or more functions of internal combustion engines or in other industrial applications. 
     The main drawback with conventional valve actuator assemblies is that the valve typically needs to be biased closed with an extremely high spring pre-load in order to counter-act or negate the force created by the working pressure of fluid (or gas) against the face of the valve. Another problem with conventional valve actuator assemblies is that the high spring pre-load requirement reduces the responsiveness of the actuator to control the valve. Another problem with conventional valve actuator assemblies is that they are typically over-designed to be far more robust than they would otherwise need to be in order to withstand the high spring pressures mentioned heretofore. 
     While the valve actuator assemblies just described may be suitable for the particular purpose to which they address, it would be desirable to reduce the high spring pressures in order to reduce the design requirements of the valve and actuator and improve responsiveness. 
     SUMMARY 
     In view of the foregoing disadvantages inherent in the known types of valve actuator assemblies now present in the prior art, the embodiments described herein provide for a new valve and counter-biased valve actuator assembly. The counter-biased valve and actuator assembly uses a fluid (or gas) working pressure to eliminate, reduce, or overcome a force acting on the face of a valve by communicating a common working pressure of the fluid (or gas) to a substrate with a resultant force vector opposite of the valve face, wherein the same can be utilized for improving the function of the common valve and actuator assembly design as it is known heretofore. 
     The general purpose of the embodiments described herein, which will be described subsequently in greater detail, is to provide a new valve and valve actuator assembly, counter-biased by a working fluid (or gas) pressure, that has many of the advantages of the valve actuator assemblies mentioned heretofore and many novel features that result in a new valve and valve actuator assembly, counter-biased by working fluid (or gas) pressure, which is not anticipated, rendered obvious, suggested, or even implied by any prior art valve actuator assemblies, either alone or in any combination thereof. 
     To attain this, the embodiments described herein generally comprise a valve and a pneumatic/hydraulic piston actuator assembly. The valve comprises a standard valve defined by a valve stem and a valve head, the valve head having a valve face. However, the valve differs from the prior art by having a port formed axially through the length of the valve, through the valve face and extending through the end of the valve stem. The port communicates a fluid (or gas) working pressure acting on the valve face to a counter-biasing chamber. 
     One object of the embodiments described herein is to provide a valve and counter-biased valve actuator assembly, counter-biased by a working fluid (or gas) pressure, that will overcome the shortcomings of prior art devices. 
     Another object of the embodiments described herein is to provide a valve and valve actuator assembly, counter-biased by a working fluid (or gas) pressure, for improving the function of a common valve and actuator assembly design, as it is known heretofore. 
     Another object is to provide a valve and valve actuator assembly, counter-biased by working fluid (or gas) pressure, that eliminates, reduces, or overcomes a force acting on the face of a valve by communicating a common working pressure of the fluid (or gas) to a substrate with a resultant force vector opposite the valve face. 
     Another object is to provide a valve and valve actuator assembly, counter-biased by a working fluid (or gas) pressure, that reduces the need for unnecessarily high spring or force pre-loads to bias the valve closed against the fluid (or gas) working pressure. 
     Another object is to provide a valve and valve actuator assembly, counter-biased by a working fluid (or gas) pressure, that improves the actuation response time, measured by the ability of the valve to operate at higher frequencies, by reducing or eliminating the spring or force pre-load to bias the valve. 
     Other objects and advantages of the present invention will become obvious to the reader and it is intended that these objects and advantages are within the scope of the embodiments present herein. 
     To accomplish the above and related objectives, the embodiments described herein are illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are for illustrative purposes only, and that changes may be made in the specific construction illustrated without departing from the general concepts described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features, advantages, and objects of the present invention will become more apparent from the detailed description as set forth below, when taken in conjunction with the drawings in which like referenced characters identify correspondingly throughout, and wherein: 
         FIG. 1  illustrates a valve actuator assembly in accordance with one embodiment, shown in a perspective view; 
         FIG. 2  illustrates the valve actuator assembly of  FIG. 1  in a cutaway view; 
         FIG. 3  illustrates another embodiment of an actuator piston used within the valve actuator assembly of  FIG. 1  or  FIG. 2 ; and 
         FIG. 4  illustrates the valve actuator assembly of  FIG. 1  or  FIG. 2  used in a typical automotive application, in this example, a turbocharged automotive engine. 
         FIG. 5  is a cross-section of a monolithic actuator piston and valve of similar shape to the actuator piston and valve assembly illustrated in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Valve actuator assemblies are typically used to control the position of a valve in applications to perform flow or pressure regulation through the valve actuator assembly. The embodiments described herein provide for an ability to alter the influence of working pressures acting on a face of a valve in such an assembly. The fluid or gaseous pressure acts on a surface area of the valve face and generally produces a resultant force in a vector normal and opposite to this surface. One of the primary objectives of the embodiments disclosed herein is to reduce, eliminate, or overcome the force of the working pressure on the valve face. 
     Turning now to the drawings,  FIG. 1  illustrates a valve actuator assembly in accordance with one embodiment, shown in a perspective view. Valve actuator assembly  100  comprises an inlet port  102 , an outlet port  104 , a valve housing  106 , and an actuator housing  108 . Other components of valve actuator assembly  100 , not visible in  FIG. 1 , will be described later herein. Valve actuator assembly  100  attaches to conduit  110  via channel  112  via screws or other known fastening methods. It should be understood that inlet port  102  and outlet port  104  may be interchanged, i.e., fluid or gas may, alternatively, enter port  104  and exit via port  102 . Outlet port  104  connects to a second conduit (not shown) which carries the gas or liquid from outlet port  104 . The flow of fluid or gas from conduit  110  to the second conduit is controlled by a valve contained within valve actuator assembly, which is described in more detail below. 
     The actuator housing  108  is defined in one embodiment to mate with an actuator piston (not shown), the resultant combination thus functioning as a single-tier actuator piston. Their mating defines at least two volumetric chambers in the actuator housing  108 , which will be described in greater detail later herein. 
     The actuator housing  108  is typically characterized as a two-component structure modeled about the geometry of the actuator piston. In one embodiment, the actuator housing assembly takes the form of two-chambers and has the ability to accommodate either the actuator piston based on a two-substrate diaphragm or a singular component design. In another embodiment, the actuator housing is defined by the geometry of a multi-tiered actuator piston described in  FIG. 3  later herein. 
       FIG. 2  illustrates the valve actuator assembly  100  of  FIG. 1  in a cutaway view. Shown is valve actuator assembly  100  mounted to a conduit  110  via channel  112 . Valve actuator assembly  100  is typically secured to channel  112  via retaining screws or some other type of mechanical fastener. Valve actuator assembly  100  comprises a valve  200 , which is commonly known as a “poppet” valve. Other types of valves could be used in alternative embodiments. Valve  200  is defined by a valve stem  202  and valve head  204 , the valve head  204  having a valve face  212 . Valve  200  is secured via a channel  206  formed between valve housing  208  and actuator housing  108 , with one end of valve  200  being retained within actuator piston  216 , as shown. The actuator piston  216  generally retains the valve  200  so as to impart resultant fluid or gaseous pressures acting on substrate areas of the piston, as will be explained in more detail below. 
     Valve  200  further comprises a port  210  defined axially through the entire length of valve  200 , including stem  202  and valve face  212 . A second port  218  is defined through actuator piston  216  that is at least partially aligned with port  210  in valve  200 . The combined ports  210  and  218  form an opening or conduit that communicates working fluid (or gas) pressure from the conduit  110  acting on the valve face  212  to a counter-biasing chamber  214 . In another embodiment, as shown in  FIG. 5 , the valve  200  and actuator piston  216  are formed as a single unit having a single port  219  formed through the entire structure, from valve face  212  through substrate area  220 . 
     The substrate area  220  of actuator piston  216  in the counter-biasing chamber  214  forms a surface that is subjected to a resultant vector force asymmetrically normal to the force imposed against valve face  212 . In other words, the fluid or gas pressure in conduit  110  is imparted to counter-biasing chamber  214  via ports  210  and  218 , which acts on the substrate area  220  of actuator piston  216 , driving actuator piston  216  down, in this case, towards conduit  110 . The force on actuator piston  216  is proportional to the amount of surface area of substrate area  220 ; the larger the surface area, the greater the force on actuator piston  216 . 
     The actuator piston  216  acts as both the main actuator and valve retainer. In one embodiment, as shown in  FIG. 2 , the actuator piston in combination with housing  108  forms multiple pressure control chambers  214 ,  226 ,  228  and  236 . Each of these control chambers are associated with a substrate area, or surface, of a portion of actuator piston  216 , which. These are shown as substrate areas  220 ,  238 ,  222 , and  242 , respectively, shown in bold. It should be understood that these control chambers and substrate areas have a cross section that is generally associated with the overall geometry of the actuator housing  108 , in this embodiment, circular when viewed from above. Each of the pressure control chambers is connected to a respective pressure control port, shown as pressure control ports  210 / 218 ,  230 ,  232 , and  240 , respectively. 
     The force exerted on actuator piston  216  is in proportion to the pressures seen inside each of the control chambers and associated substrate areas of piston actuator  216  upon which the pressure is exerted. The number of control chambers may vary depending upon the application. In addition, the number of chambers in use in any particular application may vary. For example, a valve actuator assembly could be designed and built comprising 3 control chambers, while in use, only applying a pressure control signal to two of the three control chambers. Any unused control chambers may be sealed by installing a cap onto a respective pressure control port or they may be left open to atmospheric pressure, depending upon the particular application. 
     The actuator piston  216  is generally defined by, but not limited to, three commonly known geometries. In one embodiment, as shown in  FIG. 2 , the actuator piston  216  comprises a simple valve retainer that is connected to a two-substrate flexible diaphragm. In another design, the actuator piston  216  comprises a single component that retains the valve and has two substrate areas in counter axial orientations. In yet another embodiment, the actuator piston  216  comprises a multi-tiered design as described by U.S. Pat. No. 6,863,260 wherein it acts as a retainer, but also defines four volumetric chambers and four actuation substrates. This design is described in  FIG. 3  and explained as follows. 
       FIG. 3  illustrates another embodiment of actuator piston  216 , shown here as actuator piston  316 . As shown, actuator piston  316  comprises an elliptical or polygonal-profiled object extruded in one axis of varying diameters. Actuator piston  316  comprises a shaft  318  and tiers  300 - 314 , each tier comprising a different geometric profile from other tiers, or levels, extruded on actuator piston  316 . Each tier may have different diameters, widths or dimensions to define a surface area available for a pressure control signal to act upon. Shaft  318  comprises a longitudinal extension, such as a rod, or cylinder, having one of any number of cross-sections, extending the length of actuator piston  316  around which the various tiers are imposed. Shaft  318  additionally comprises a first shaft end  326  and a second shaft end  328 . In some cases, a tier may have a diameter equal to the diameter of shaft  318 , for example, tiers  300 ,  310 ,  312 , and  306 . A resultant force on actuator piston  316  is produced by the combination of pressure control signals acting upon the different surface areas defined by the tiers. 
     The geometric profiles representing the tiers do not necessarily have to be axially aligned. The most common implementation of actuator piston  316  will be one wherein actuator piston  316  will travel in an axial direction that is perpendicular to the geometric profiles of the tiers. The piston/housing relationship typically assumes that actuator piston  316  will be the component that will travel and move in relation to the actuator housing  108 . 
     Each tier generally comprises a top surface, a bottom surface, and an outer wall, such as top surface  320 , and an outer wall  324  (a bottom surface not shown). A top surface of one tier may be a bottom surface of another tier. For example, top surface  320  of tier  302  is the same surface as a bottom surface of tier  310 ; the bottom surface of tier  302  is the same surface as a top surface of tier  308 . As mentioned previously, the outer walls of some, or all, of the tiers are in contact with the various inner walls defining cavities of actuator housing  108 . This contact forms chambers that change in volume as either actuator piston  316 , or actuator housing  108 , travels along an axis common to both components. The surfaces of the cavity inner walls may act as a sealing surface with either the material of the tiers or with a seal housed by, or integrated into, the tier outer walls. Alternatively, actuator housing  108  may comprise materials for providing a sealing surface with the tiers. Furthermore, independent seals such as O-rings, for example, can also be integrated into the tiers and/or shaft  318 , to mate with the housing cavity inner surfaces to create a seal. Any number of existing seal technologies can be integrated into actuator piston  316 , including, but not limited to, o-rings, washers and metal seals. In the example of  FIG. 3 , such independent seals may be placed around tier  314 , tier  308 , or tier  303 . 
     Although shown in  FIG. 3  as a piston of single-piece construction, actuator piston  316  can alternatively be constructed of distinct and separate objects that fit the aforementioned description and that are connected together to form resultant actuator piston  316 . Accordingly, actuator piston  316  may be manufactured of any currently available materials, such as plastic, metal, or any other rigid or semi-rigid material, depending on each particular application. 
     Referring back to  FIG. 2 , pressure control signals may be communicated to control chambers  226 ,  228 , and  236  via pressure control ports  230 ,  232 , and  240 , respectively, to control operation of valve  202 . These pressures each may be applied as positive pressures or negative pressures and may originate from different sources. The pressure control signals typically comprise gas, liquids, or a combination of the two. In addition, each pressure control port could transmit a unique pressure type. For example, the pressure control signal communicated to pressure control port  230  could comprise a gas while the pressure control signal communicated to pressure control port  232  could comprise a liquid. The pressure control signals introduced to pressure control ports  230 ,  232 , and  240  can either be the same or mutually exclusive, and may be introduced at varying points in time so as to control the position of valve  202  relative to sealing surface  234 , and thereby controlling the flow of material from discharge port  104 . In any given application, there can exist a multiplicity of chambers defined by annular walls, end walls, and tier surfaces used to create forces operating against actuator piston  216 . The quantity of such chambers, tier surface areas, or other chamber-defining characteristics need not be equal or similar. 
     Actuator piston  216  will move in one of two directions, either up or down with respect to actuator housing  108 . For example, if a pressurized fluid is communicated through pressure control port  232  into control chamber  228 , that fluid, barring any other forces acting on actuator piston  216 , will act to effectively move the actuator piston  216  in a direction that allows for the expansion of the pressurized fluid or gas into chamber  228 . The actuator piston  216  will move in a direction where the force will find a differential, i.e., in an upward movement in this example, or away from conduit  110  and, in turn, cause valve  200  to open with respect to sealing surface  234 . 
     The actuator piston  216  will be displaced in a direction proportional to the net combined force operating against each substrate surface and the valve face. Each of the forces against the substrate surfaces are, in turn, proportional to pressure signals applied via pressure control ports and into respective pressure control chambers, against respective substrate surface areas. For example, a positive pressure signal applied to control chamber  226  via pressure control port  230  would be offset an equal, positive pressure signal applied to control chamber  228  via pressure control port  232  if both substrate areas  238  and  222  are equal in surface area. In this case, piston actuator  216  and valve  200  would not move. In another example, if the same pressures were applied to control chambers  226  and  228 , but the surface area of substrate  238  was twice as great as the surface area of substrate  222 , then the piston actuator  216  would move toward the closed position shown in  FIG. 2 . In yet another example, if a positive pressure is communicated to pressure control port  230  and a negative pressure is communicated to pressure control port  232 , and the tier surfaces of each control chamber are equal, the actuator piston  216  will move in a downward direction at twice the force of each individual pressure control signal (assuming, of course, that the valve  202  has not yet contacted sealing surface  234 ). 
     Assembly of valve actuator assembly  100  generally begins with the actuator housing  108  mating with the actuator piston  216 , which then mates with the valve  202  and finally valve housing  208 . There are several permutations of design and assembly available. Other embodiments may find that the design requirements necessitate a one-piece valve and actuator piston design. The interconnectivity of the components would be fundamentally unchanged however. 
     There exists myriad methodologies to manufacture these components. Processes that can be used include, but are not limited to, investment casting, die casting, injection molding and wrought machining. Materials that can be used can include, but are not limited to, ferrous and non-ferrous metals, plastics and advanced resin-based composites. 
       FIG. 4  illustrates a valve actuator assembly  400  used in a typical automotive application, in this example, a turbocharged automotive engine  402 . Ambient air enters an inlet  404  of turbocharger  403  to be compressed and routed to a charge cooler  406  via ducting  408 . The compressed air then enters the engine  402  and the spent gases exit through ducting  410  and into an inlet of an exhaust turbine section  412  of turbocharger  403 . In order to regulate the operating speed of the turbocharger, a regulating valve, commonly known as a wastegate, is generally required. These mechanical valve assemblies typically comprise a common “poppet” valve that regulates exhaust gas pressure and flow entering the turbocharger. The valve is typically biased in the closed position by a spring inside a valve housing assembly. In the example of  FIG. 4 , this regulating valve comprises valve actuator assembly  400  as described previously hereto. The valve inside valve actuator assembly  400  may be biased in a closed position by a spring and the valve and actuator inside the valve assembly  400  comprises ports  210  and  218  to respond to the pressure of the gas inside ducting  410  acting on the valve face. Attributes of the spring, such as the size, restoring force, and spring constant, is typically reduced from what would normally be required to bias the valve in the closed position, due to the equalizing effect of ports  218  and  210 . 
     In the example of  FIG. 4 , valve actuator assembly  400  is controlled by an actuating pressure control signal  414  from the compressed ambient air from turbocharger  403  prior to entering cooler  406 . It should be understood that this pressure control signal  414  could, alternatively, originate from the outlet of cooler  406  or be supplied from a source other than the components shown in  FIG. 4 . In the example of  FIG. 4 , the pressure control signal  414  is a positive pressure, connected to pressure control port  232 , that operates to open the valve inside the actuator assembly  400 . As the valve is opened, exhaust gases from ducting  410  are passed by the valve actuator assembly  400  and discharged through conduit  416 , typically to ambient air or a noise-suppression system. As the valve inside valve actuator assembly  400  opens, pressure and flow of exhaust gasses is reduced inside ducting  410 , thereby slowing the rotation of turbocharger  403 . If the pressure inside ducting  408  becomes too small, pressure control signal  414  likewise is reduced, causing the valve inside valve actuator assembly  400  to close, thereby increasing the pressure inside ducting  410 . As a result, turbocharger  403  increases it&#39;s rotation. In this manner, a feedback loop is established to regulate turbocharger  403 . 
     It should be noted that in this example, there is only one pressure control signal applied to the valve actuator assembly, pressure control signal  414  connected to pressure control port  232 . The second pressure control port remains unconnected. In this arrangement, the force of the exhaust inside ducting  410  and the pressure control signal  414  acts to push the valve open, while a biasing spring acts to close the valve. In other embodiments, the second pressure control port can be connected to a second pressure control signal to further control operation of the valve. In still other embodiments, valve actuator assembly  400  could comprise more than two pressure control ports, each pressure control port connected to a particular control chamber within the valve actuator assembly. Finally, in other embodiments, one or more unused ports may be capped so that any gases inside respective control chambers remains trapped inside those control chambers. 
     With respect to the above description, it is to be realized that the optimum dimensional relationships of the various components of the pipe couplers include variations in size, materials, shape, form, function and manner of operation, assembly and use, and are deemed readily apparent and obvious to one skilled in the art. All equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the embodiments described herein. Therefore, the foregoing is considered as illustrative only of the principles and descriptions provide herein. Further, since numerous modifications and changes may be contemplated by those skilled in the art, it is not desired to limit the embodiments described herein to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the present disclosure.