Abstract:
A thermo-hydraulically actuated valve including a housing; a closure member capable of preventing and permitting fluid flow through the housing. An actuation fluid chamber disposed at the housing and sealed from an external environment. A motive force transmitter in force transmissive communication with the closure member. The transmitter being in fluid communication with the actuation fluid chamber; and a heating element in thermal communication with the actuation fluid chamber. The valve being devoid of a dynamic seal between an area of the valve to be contacted by a managed fluid within the valve and an environment outside of the valve.

Description:
BACKGROUND 
       [0001]    Process control valves are used in many industries to control fluid movement for a plethora of reasons. Some of the fluids controlled by such valves are difficult to handle such that their escape from the system is undesirable. Hydrogen Sulfide is one such fluid and will be recognized by those of skill in the art as a gas that one would prefer did not escape the system in which it is housed. 
         [0002]    Traditional process control valves include an open or close lever that is mechanically actuated either manually or by mechanism. While such valves do control flow of the subject fluid, they also suffer from the fact that they contain a dynamic seal between the subject fluid and the environmental atmosphere. This dynamic seal exists about a shaft connected between the valve member itself and the lever. Since dynamic seals require periodic maintenance and represent a potential leak path for the subject fluid to reach environmental atmosphere and since as has been stated above it would be desirable to provide systems that more robustly contain the subject fluid within the system in which they are housed, the art would well receive alternate process control valves that improve confidence of containment. 
       SUMMARY 
       [0003]    A thermo-hydraulically actuated valve including a housing; a closure member capable of preventing and permitting fluid flow through the housing; an actuation fluid chamber disposed at the housing and sealed from an external environment; a motive force transmitter in force transmissive communication with the closure member, the transmitter being in fluid communication with the actuation fluid chamber; and a heating element in thermal communication with the actuation fluid chamber, the valve being devoid of a dynamic seal between an area of the valve to be contacted by a managed fluid within the valve and an environment outside of the valve. 
         [0004]    A thermo-hydraulically actuated valve including a housing devoid of a dynamic seal between a managed fluid area of the valve and an environment outside of the valve; a closure member in the housing; an actuation fluid in pressure communication with the closure member; and an element capable of causing a change in the pressure of the actuation fluid. 
         [0005]    A thermo-hydraulically actuated valve including a housing devoid of a dynamic seal between a managed fluid area of the valve and an environment outside of the valve; a closure member in the housing; a first actuation fluid in pressure communication with the closure member configured to have a motive effect with respect to the closure member in one direction; a second actuation fluid in pressure communication with the closure member configured to have a motive effect with respect to the closure member in another direction; a first element capable of causing a change in the pressure of the first actuation fluid; and a second element capable of causing a change in the pressure of the second actuation fluid. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
           [0007]      FIG. 1  is a Thermo-Hydraulically Actuated Process Control Valve disclosed herein in a closed position; 
           [0008]      FIG. 2  is the Thermo-Hydraulically Actuated Process Control Valve of  FIG. 1  in an open position; 
           [0009]      FIG. 3  is a representation of an alternate embodiment of the valve disclosed herein; 
           [0010]      FIG. 4  is a representation of another alternate embodiment of the valve disclosed herein; 
           [0011]      FIG. 5  is a representation of another embodiment of the valve disclosed herein; 
           [0012]      FIG. 6  is a representation of another embodiment of a valve disclosed herein in an closed position; 
           [0013]      FIG. 7  is a representation of the embodiment of  FIG. 6  disclosed herein in a open position; 
           [0014]      FIG. 8  is a representation of another embodiment of a valve disclosed herein in an open position; and 
           [0015]      FIG. 9  is a representation of the embodiment of  FIG. 8  disclosed herein in a closed position. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring to  FIG. 1 , a process control valve  10  includes a tubular housing  12  that is connectable in series with other tubular members (not shown) that are a part of an overall fluid management system. Within the housing  12  is a closure member  14  capable of preventing and permitting managed fluid flow though the housing, such as a flapper. The closure member is in communication with a motive force transmitter  15 , which is itself in operable communication with an actuation fluid discussed below. 
         [0017]    In the embodiment illustrated in  FIG. 1 , the flapper  14  is pivotable from a closed position to an open position about pivot  16 . The pivot  16  is connected to the housing  12  so that a flow tube  18 , in the illustrated embodiment will force the flapper  14  open upon stroking of the flow tube  18 . A support  20  is schematically illustrated that is interactive with a power spring  22  connected to the flow tube  18  at flange  24 . The flow tube when moved to the right of the Figure will cause compression of the spring  22  between the support  20  and the flange  24 . The flow tube  18  will also urge the flapper  14  to the open position. If a motive force acting on the flow tube to compress the power spring  22  is withdrawn, the spring will move the flow tube  18  toward the left of the figure and allow a torsion spring (not shown) within the pivot  16  to close the flapper  14 . The motive force alluded to is transmitted to the flange  24  via a piston rod  26  that is disposed within a piston cylinder  28  and includes a piston  30 . The piston  30  includes a dynamic seal thereabout (not shown) such as a piston ring or set of rings to allow the piston to respond to fluid pressure acting thereon. It will be understood that although a discrete piston is shown, more of these may be employed or an annular piston might be substituted therefor. The other side of the piston  30  is exposed to an actuation fluid  31  that is contained within a sealed chamber  32 . In the illustrated embodiment, the chamber is an annular chamber but it is to be understood that any shape is acceptable. The chamber is penetrated, in the embodiment of  FIGS. 1 and 3 , by a static seal  34  that admits at least one of a heating element  36 / 136  and/or energy supply conduit  35 . It is to be understood that the element or conduit are examples and that other things could also be admitted via the seal  34  as the particular application might require. Note however, in an alternate embodiment illustrated in  FIG. 4  that the heating element  236  is disposed entirely outside of the chamber  32  and requires no penetration of the chamber  32 . Power and or communication with the element  236  is supplied via line  237  entirely outside of the chamber  32 . If a particular embodiment using heating element  236  has no other reason for a penetration of the chamber  32 , then no seal  34  would be needed in such embodiment. The embodiment of  FIG. 4  otherwise works identically to that of the other embodiments herein including any optional configurations. 
         [0018]    It will be appreciated that other things could also be admitted through this seal  34  if desired depending upon what might be necessary or desirable for a particular application. In the illustrated embodiment, also admitted is a communication line  38  connected to a position sensor  40 . Because the seal  34  is static in nature, there is no significant possibility of a leak. The seal must suffer no dynamic capability and hence is by definition more reliable. 
         [0019]    The position sensor may be a magnetic type or other proximity sensor that allows for a confirmation of the location of the flow tube  18 . 
         [0020]    For clarity, it is noted that the element  36  in  FIG. 1  is a rod type element and the element  136  in  FIG. 3  is annular configured. In each case, the element functions to heat the actuation fluid. 
         [0021]    In order to increase fluid pressure within chamber  32 , the heating element  36 / 136  is energized and causes the temperature of the actuation fluid such as hydraulic fluid in chamber  32  to increase leading to expansion thereof. The coefficient of thermal expansion of the actuation fluid may be selected (by selection of a suitable fluid or by chemically modifying a fluid to custom tailor the coefficient of thermal expansion of the fluid.) as desired to create the degree of motive force needed for the application. Upon the heating of the fluid in chamber  32 , the piston  30  is urged toward the flapper  14  thereby causing the rod  26  to bear against the flange  24  and force the flow tube  18  to move toward the flapper  14  and to push the flapper  14  to the open position as shown in  FIG. 2 . Cooling of the fluid in chamber  32  will allow the flow tube to return to the position in  FIG. 1  pursuant to the power spring  22  urging the flow tube  18  to an unactuated position. 
         [0022]    It is to be appreciated that the exact configuration of the invention is not limited to that illustrated in the drawings. Rather, the concept of the invention has broader reach in that it requires a fluid in a chamber that can be heated so that the fluid pressure in the chamber increases whereby the fluid causes the piston that ultimately acts on a flapper or other valve member to open the same. The use of heat and an actuation fluid to provide motive force for the change in position of a valve means that there need be no dynamic seals in the system and hence that there can be no leaks of the managed fluid within the system to the environment. 
         [0023]    In one embodiment, it is noted that the actuation fluid  31  is pre pressurized so that the amount of thermal expansion needed for actuation of the valve is less. This of course translates to less needed power for the heating element as the temperature increase necessary in the actuation fluid will be comparatively less due to the preexisting pressurization of the actuation fluid. Such pressurization of the fluid may be accomplished at manufacture of the valve or could be applied on site, but in the latter embodiment a static seal will be required in the chamber. In the event a static seal is already supplied as in the  FIG. 1  or  3  embodiments, there is no additional seal required but in the case of  FIG. 4 , a seal would be needed where one was not before required. 
         [0024]    In another embodiment, referring to  FIG. 5 , the valve is again prepressurized but also included is a pressure dump configuration  350  so that the valve can be quickly closed. The dumped pressure can be to anywhere that is convenient but in keeping with the concept of having fewer seals (and no dynamic ones) between the managed fluid and atmosphere, the dump may be to a dump chamber  352  having a predetermined lower pressure than the pressure of the actuation fluid. The chamber will itself comprise a valve  354  of some type to admit the pressurized actuation fluid in the event a dump is desired. This may be by way of burst disk, such that increasing the pressure of the actuation fluid will automatically at a predetermined pressure threshold cause the valve to close due to rapid depressurization of the chamber  332 . Alternately this may be by way of a remotely controllable valve in the same location  354  such that upon command the valve will open and reduce the actuation fluid pressure by flooding the dump chamber  352 . The valve  354  may be externally powered thought the seal  334  or may use local power source that does not require a seal  334  and as such would be used in the configuration of  FIG. 4 . 
         [0025]    Regardless of which type of valving method or mechanism is used to admit fluid to the dump chamber  352 , immediately upon opening of the chamber, the actuation fluid pressure will drop due to the effectively increased volume of the chamber  332  (volume of  332  plus volume of  352 ). 
         [0026]    Referring again to the  FIG. 4  embodiment, it is to be understood that the heating element  236  illustrated therein may be an inductive heating element. 
         [0027]    It should be understood that it is possible not only to actuate the closure member to open and closed positions within the embodiments hereof but is also possible to actuate the closure member to any position between open and closed if desired depending upon fluid pressure applied to the piston. 
         [0028]    It is further to be understood that there is no requirement that the valve as disclosed herein be of a fail-safe closed design. There is no requirement that the power spring be incorporated at all. In view hereof, an alternative embodiment (see  FIGS. 6 and 7 ) utilizes two configurations of heating elements and volumes to move the flow tube in opposing directions based upon which fluid volume is energized. Reference to  FIGS. 6 and 7  will make the concept clear where numerals as disclosed above are retained for one side of the device and four hundred series similar numerals are used to denote the mimicked components that will be positioned to actuate in a direction opposed to the first set of components. More specifically, and with direct reference to  FIGS. 6 and 7 , a reader having understood the foregoing disclosure will recognize the components numbered on the left side of the Figures. The reader will also understand the four hundred series numbers on the right side of the Figures. It is noted that the fluid volumes  31  and  431  are separate so that thermal input thereto will be substantially restricted to one of the sets of components. Components with four hundred series numerals are introduced below in list form for convenience of the reader: additional actuation fluid volume  431 , heating element  436  (note other heating means as described herein are applicable to this embodiment as well as those in which they are illustrated), piston  430 /and rod  426 . These are configured such that when actuated the components identified provide a motive force to retract the flow tube  418 , consequently enabling the closure member  414  to return to the closed position. The functional valve condition (open or closed) in this alternative embodiment will correspond to that actuation fluid volume which has been selectively and exclusively energized. 
         [0029]    Referring to  FIGS. 8 and 9 , it is easily recognized that the embodiment is similar to the foregoing  FIGS. 6 and 7  but the distinction therefrom, i.e. the ball valve in substitution for the flapper is equally employable for any of the other embodiments illustrated herein where a flapper is illustrated. Ball valve  500  is illustrated in an open position in  FIG. 8  and a closed position in  FIG. 9 . The motive force to move the ball valve  500  in one direction or the other is provided by the same components as discussed with respect to  FIGS. 6 and 7 . In addition, it will be appreciated that either of the sets of components in those figures could be substituted for by a spring configuration such as in  FIG. 1 . In embodiments where the flapper is substituted by the ball valve  500 , the flow tube  518  causes the ball valve to rotate to either a closed position from an open position or an open position from a closed position by means of rotation pins  501  incorporated on the flow tube  518  and grooves  503  on the exterior of the ball  505 . Pivot pins  507  are also incorporated on the exterior of the ball  505  at its rotational axis. As the Flow Tube  518  extends and retracts during actuation, the rotation pins  501  engage the exterior grooves  503  on the ball causing the ball to rotate between the open and closed position. The configuration may also incorporate a means of translation of the ball relative to the ball seat, in addition to the rotational action described above. 
         [0030]    While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.