Patent Publication Number: US-2018045118-A1

Title: Pressure regulating valve with flow anti-rotation

Description:
BACKGROUND OF THE INVENTION 
     This invention generally relates to a pressure regulating valve, and more particularly, to a sleeve of a pressure regulating valve for use in a fuel line of an aircraft engine. 
     Gas turbine engines are typically used to power an aircraft. A fuel system provides fuel to various portion of the gas turbine engine. The fuel system includes various valves such as a pressure regulating valve, a high pressure relief valve, and a filter bypass valve that cooperate with each other to supply fuel to the gas turbine engine in a controller and accurate manner. 
     During operation of the fuel system, the pressure regulating valve commonly experiences a rotational force due to the fluid flow there through. In conventional assemblies, an anti-rotation device is positioned between the spool and the sleeve of the pressure regulating valve to minimize the effects of the rotational force, or not included if fluid housing does not cause flow rotation. The flow through the valve, and any rotational forces resulting from the flow, are dependent on the valves position within the fluid housing. As a result, the pressure regulating valves arranged within the fluid housing are not interchangeable with other systems because the anti-rotation device (or lack thereof) of each is dependent on the housing arrangement. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one embodiment, a sleeve for a pressure regulating valve includes a sleeve body surrounding a central axis and defined by an overall length extending from a first end to a second end. The sleeve body has a central sleeve bore extending from the first end to the second end. The sleeve body includes a first set of windows circumferentially spaced about the central axis and a second set of windows axially spaced from the first set of windows and circumferentially spaced about the central axis. Each window of the first set of windows is defined by a plurality of small holes. 
     According to another embodiment, a sleeve for a pressure regulating valve includes a sleeve body surrounding a central axis and defined by an overall length extending from a first end to a second end. The sleeve body has a central sleeve bore extending from the first end to the second end. The sleeve body includes a first set of windows circumferentially spaced about the central axis and a second set of windows axially spaced from the first set of windows and circumferentially spaced about the central axis. Each window of the first set of windows radially aligns a fluid flow there through. 
     According to another embodiment, a pressure regulating valve includes a valve housing defining an internal bore and having a valve inlet to receive a fluid at a first pressure and a fluid outlet to return fluid to a pump. A sleeve surrounds a central axis and is defined by an overall sleeve length extending from a first sleeve end to a second sleeve end. The sleeve body has a central sleeve bore. The sleeve includes a set of windows circumferentially spaced about the central axis adjacent the valve inlet. Each window of the set of windows is defined by a plurality of small holes. A piston is received within the central sleeve bore. A spring assembly biases the piston within the sleeve to a valve closed position. When the pressure at the valve inlet is greater than a spring biasing load, the piston moves to a valve open position to provide fluid to the valve outlet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic diagram of a fuel system for an aircraft; 
         FIG. 2  is an exploded view of an example of a pressure regulating valve of  FIG. 1 ; 
         FIG. 3  is cross-sectional view of the pressure regulating valve of  FIG. 2  in a closed position; 
         FIG. 4  is cross-sectional view of the pressure regulating valve of  FIG. 2  in an open position; 
         FIG. 5  is a perspective view of a sleeve of a pressure regulating valve according to an embodiment; 
         FIG. 6  is a cross-sectional view of the pressure regulating valve including the sleeve of  FIG. 5  in a closed position according to an embodiment; and 
         FIG. 7  is a cross-sectional view of a predicted fluid flow path through a pressure regulating valve having a sleeve of  FIG. 5  according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a schematic diagram of an aircraft fuel supply system  20  configured to supply fuel to an engine, such as the engine illustrated in  FIG. 1  for example. The supply system  20  includes a fuel pump  22  that draws fuel from a fuel supply  24 . The pump  22  has a pump inlet  26  in fluid communication with the fuel supply  24  and a pump outlet  28  in fluid communication with a metering valve  34  and a pressure regulating valve  38 . Fuel passes through a filter  342  to remove contaminants therefrom. Fuel exiting the filter  32  is then directed to the metering valve  34  to supply fuel to an engine  36 . The pressure regulating valve  38  receives pressure inputs from sense lines around the metering valve  34  to regulate the pressure across the metering valve  34 . If the supply of fuel at the metering valve exceeds an amount necessary for the current operating condition of the engine, the pressure regulating valve returns the excess fuel to the pump inlet  26 . 
     An example of a pressure regulating valve  38 , such as used in the fuel supply system  20  is illustrated in more detail in  FIGS. 2-4 . The pressure regulating valve  38  include a closure  40 , piston  42 , spring  44 , spacer  46 , adjusting screw  48  and a sleeve  52 . The pressure regulating valve  38  additionally includes a valve housing having a pressure inlet  54  arranged in fluid communication with the metering valve  34  and a pressure outlet  56  that returns excess fuel to the pump  22 . The valve housing  50  defines a valve center axis A and has an internal cavity that provides at least three main chambers. A first chamber  58  receives fuel from the pressure inlet  54 , a second chamber  60  is provided at the pressure outlet  56 , and a third chamber  62  receives the closure  40  and adjusting screw  48 . In the example shown, the first chamber  58  is positioned axially between the second  60  and third  62  chambers. 
     The valve housing  50  extends from an open first end  64  to an enclosed second end  66 . The sleeve  52  is inserted through the open first end  64  and is held fixed within the valve housing  50  by inwardly, or radially, extending seat portions  68 . The seat portions  68  cooperate with the sleeve  52  to define the chambers. The sleeve  52  is positioned substantially within the first  58  and second  60  chambers. The enclosed second end  66  of the valve housing  50  includes a recess  70  that receives a first end  72  of the sleeve  52  in a press-fit. A seal  74  is provided between an outer surface of the sleeve  52  and an inner surface of the recess  70 . 
     An outer surface of the second end  76  of the sleeve  52  is sealed against one seat portion  68  with a seal  78 . An outer surface of a center portion  80  of the sleeve  52  is sealed against another seat portion  68  with a seal  82 . The sleeve  52  comprises a cylindrical body that is open at each sleeve end  72 ,  76  to define a central sleeve bore  84 . 
     The sleeve  52  includes a first set of windows  86  that are positioned within the first chamber  58  and a second set of windows  88  that are positioned within the second chamber  60 . The first set of windows  86  is in fluid communication with the pressure inlet  54  and the second set of windows  88  is in fluid communication with the pressure outlet  56 . 
     The spool or piston  42  slides within the sleeve bore  84 . The piston  42  extends from a first end  90  to a second end  92 . An outer surface of the first end  90  abuts against an inner surface of sleeve  52  and also slides along the inner surface of the sleeve  52  at the first sleeve end  72 . An outer surface of the second end  92  slides along an inner surface of the sleeve  52  and also abuts the sleeve  52  at the second sleeve end  76 . The piston  42  includes a piston chamber  94  at the first end  90  that is at a fluid pressure P 1  corresponding to the fluid pressure at the pressure inlet  54 . The piston  42  includes a spring chamber  96  at the second end  92  that receives one end of the spring  44 . 
     The piston  42  includes a plurality of recessed areas  98 , referred to as “buckets,” which are formed about an outer circumference of the piston  42 . Enclosed bottom surfaces of the recessed areas  98  are radially inward of a piston outer surface  100  that contacts the sleeve  52 . The recessed areas  98  at least partially overlap the center portion  80  of the sleeve  52  when the piston  42  is fit within the sleeve  52 . When the pressure regulating valve  38  is in the closed position ( FIG. 3 ), the center portion  80  of the sleeve  52  and an outer surface  100  of the piston  42  cooperate to prevent fluid flow from the pressure inlet  54  to the pressure outlet  56 . In this position, the recessed areas  98  are not fluidly connected to the first set of windows  86  in the sleeve  52 . When the pressure regulating valve  38  is in the open position ( FIG. 4 ), the piston  42  has moved along the axis A such that the recessed areas  98  fluidly connect the first set of windows  86  to the second set of windows  88 , and thus fluidly connects the pressure inlet  54  to the pressure outlet  56 . 
     The closure  40  is positioned within the third chamber  62  of the valve housing  50  and includes a flange portion  102  that is seated against an end face of the valve housing  50  to close off the open end of the valve housing  50 . The closure  40  defines an internal cavity  104  that receives the spacer  46 , adjusting screw  48 , and spring  44 . 
     An annulus  106  is formed between an outer surface of the closure  40  and an inner surface of the valve housing  50 . A separate pressure inlet  108  supplies pressure to the annulus  106  at a second pressure P 2 . The closure  40  includes a plurality of ports  110  that are formed about an outer circumference of a first end  112  of the closure  40 . The ports  110  fluidly connect the annulus  106  with the internal cavity  104  of the closure  40 . 
     The spacer  46  includes an elongated body portion  118  with a spring seat flange  120  at one end. The elongated body portion  118  is received within the spring  44  such that one end of the spring  44  abuts against the spring seat flange  120 . An optional washer  122  ( FIG. 2 ) can be positioned between the spring end and the spring seat flange  120 . An opening  124  is formed within an end face of the spacer  46  at the spring seat flange  120 . 
     The adjusting screw  48  includes an end  126  that is inserted into the opening  124  of the spacer  46 . The adjusting screw  48  includes a flange  128  that is seated against the spring seat flange  120  when the end  126  is received within the opening  124 . The adjusting screw  48  has an elongated body  130  that extends from the flange  128  to a threaded end  132  that receives a nut  134 . A washer  152  is utilized with the nut  134  to prevent axial movement during operation. 
     The closure  40  includes end face portion  114  with a center bore  116 . The elongated body  130  of the adjusting screw  48  extends through the bore  116  into an outer cavity  138  formed within a closure extension portion  154  that extends outwardly from the end face portion  114 . The nut  134  is tightened against the end face portion  114  within the outer cavity  138  to adjust the spring force of the spring  44 . A plug  140  is inserted into the closure extension portion  154  to seal the outer cavity  138 . 
     The spring force and the fluid pressure from the separate pressure inlet  108  cooperate to bias the piston  42  to the closed position. When the pressure at the pressure inlet  200  overcomes the combination of the spring force and pressure from pressure inlet  108 , the piston moves the valve  38  to the open position to fluidly connect the pressure inlet  54  to the outlet  56 . It should be understood that the pressure regulating valve illustrated and described herein is intended as an example only, and pressure regulating valves having other configurations are within the scope of the disclosure. 
     Referring now to  FIGS. 5-7 , the sleeve  52  of the pressure regulating valve  38  is illustrated in more detail. In a conventional pressure regulating valve, each window of the first set of windows  86  includes a single large opening, and each window of the second set of windows  88  also includes a single large opening formed in the sleeve  52  (as shown in  FIGS. 2-4 ). The large openings that define the first set of windows  86  allow rotation of the fluid flow as it passes there through, which contributes to the rotational forces acting on the pressure regulating valve  38 . To reduce the rotation of the fluid flow, each window of the first set of windows  86  comprises a plurality of small through holes  200 , as shown in  FIG. 5 . The total area of the plurality of small holes  200  that define each window  86  may be substantially equal to the area of a conventional window having a single large opening. In addition, the pressure drop of the fluid as it flows through the plurality of small holes  200  that define each of the first windows  86  is substantially identical to the pressure drop if each of the windows  86  were defined by a single large opening. 
     The plurality of small through holes  200  that define a window  86  may be substantially uniform, or alternatively, may vary in size and/or shape. Although the small holes  200  are illustrated as being circular in shape, holes having another shape, such as oval or square for example, are contemplated herein. In the illustrated, non-limiting embodiment, the plurality of small holes  200  that define each window  86  are arranged in rows and/or columns with adjacent rows or columns being staggered or offset from one another. In addition, the pluralities of small holes  200  that define each of the first set of windows spaced about the periphery of the sleeve  52  may be substantially uniform or may have different configurations. In the illustrated, non-limiting embodiment, the small holes  200  that define each first window  86  are separated from one another by a distance. However, embodiments where the small holes  200  extend continuously about the entire periphery of the sleeve  52  to evenly redistribute the flow are also considered within the scope of the disclosure. 
     The small holes  200  restrict the amount and direction of fluid flow there through. In an embodiment, the small holes  200  have a length to diameter ratio between about 1 and 2. By replacing the large opening with a plurality of small holes  200 , each of the first set of windows  86  is intended to straighten or radially align the fluid flow as it passes to the pressure inlet  54 . As a result, the rotational forces acting on the pressure regulating valve  38  are reduced, and the need for an anti-rotation component is eliminated. Consequently, a pressure regulator valve  38  having first windows  86  defined by a plurality of small openings  200  may be used interchangeably between systems with different fluid housings. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.