Patent Document

FIELD OF THE INVENTION  
       [0001]     This invention relates to flow control and, more specifically, to flow control in dynamic temperature environments.  
       BACKGROUND OF THE INVENTION  
       [0002]     In certain type of jet engines, Engine Electronic Controls (EEC) units fail at an unusually high rate. Failures of these EECs are caused by the thermal cycling that occurs in a typical flight evolution. Presently, the EEC is cooled on the ground by natural convection when the jet engine is off. When the engine is on while on the ground, at takeoff power or climb, cooling air is drawn through the EEC and into the engine by low pressure produced at the engine inlet. When at altitude, the flow is from the engine inlet into the EEC due to pressure changes. Thus, a typical EEC may experience in a single flight a range of temperatures between minus 60° C. and plus 95° C. Because of the extreme differences in these operating temperatures, thermal expansion and contraction of the electronic components within the EEC occurs, thereby leading to thermal fatigue and failure. When failure occurs, the engine may be shut down. In the air, this is critical and the aircraft must land at the nearest airport. On the ground, the engine must be shut down and engine maintenance must occur. Both of these shutdown situations are very costly to both the airlines and the engine/aircraft manufacturers due to guarantees. In-flight shutdown typically costs thousands of dollars due to an aircraft having to land at a non-destination airport, and a back-up aircraft having to be called or other form of transportation arranged for the passengers. There are also the unmeasurable costs associated with adversely affecting the travel plans of all the occupants of the aircraft.  
         [0003]     In situations when an on-ground engine shutdown occurs, departure is delayed trying to resolve the problem. This can be very costly if the EEC has to be replaced. Also, the time it takes to perform the maintenance or find a new aircraft also costs a great amount of money for the airlines as well as adding to unmeasurable cost of passenger delay.  
         [0004]     Therefore, there exists a need to reduce the amount of thermal cycling that can occur in various machinery, including, for example, aircraft EEC units.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention provides a device for controlling fluid flow for heating or cooling an associated system. The present invention includes a hingeless valve that opens or closes based on the direction and quantity of fluid flow, and does not include any mechanical or electromechanical control components.  
         [0006]     In one embodiment, the device includes a housing and a flapper door coupled to the housing, the flapper door having a bendable portion. The flapper door is in an open position during a some modes of operation of the associated system, and is in a closed position in other modes of operation of the system. In the second position, the flapper door closes off material flow through the housing.  
         [0007]     In one aspect of the invention, the device is coupled to an engine electronic control (EEC) unit of an aircraft. The second nozzle is connected to the EEC unit and the first nozzle is connected to a cooling duct. The cooling duct is connected to an inlet for an engine.  
         [0008]     In another aspect of the invention, the flapper door is in one position during the ground aircraft operation, takeoff and climb engine operations, and is in another position during altitude and cruise engine operation. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings.  
         [0010]      FIG. 1  illustrates an example partial side view of an engine system formed in accordance with an embodiment of the present invention;  
         [0011]      FIG. 2  illustrates a top view of an exemplary valve formed in accordance with an embodiment of the present invention;  
         [0012]      FIG. 3  illustrates a front view of the valve shown in  FIG. 2 ;  
         [0013]      FIGS. 4 and 5  illustrate cut-away side views of the valve shown in  FIGS. 2 and 3  at two different stages of operation; and  
         [0014]      FIGS. 6 and 7  show valve positions during different modes of operation in accordance with an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     The present invention relates to flow control assemblies. Many specific details of certain embodiments of the invention are set forth in the following description and in  FIGS. 1-7  to provide a thorough understanding of such embodiments. One skilled in the art, however, will understand that the present invention may have additional embodiments, or that the present invention may be practiced without several of the details described in the following description.  
         [0016]     An example of machinery that can benefit from the present invention is an engine system  20 , as shown in  FIG. 1 . The engine system  20  includes a jet engine  24 , an engine electronic control (EEC) unit  26 , a valve  28 , and a cooling duct  30 , all of which are mounted within an engine compartment  34  surrounded by a cowling  32 . In one embodiment, the EEC unit  26  is mounted on top of the engine  24 . The valve  28  is connected to a cooling inlet port (not shown) of the EEC unit  26 . The cooling duct  30  is coupled to the valve  28  and extends to a static port  36  at the air intake end of the engine  24 .  
         [0017]     The valve  28  lets cooling air flow through the EEC unit  26  during certain modes of operation and restricts cooling air flow during other modes of operation, as described more fully below.  
         [0018]     In a first mode of operation, the EEC unit  26  is turned on and the engine  24  is off (e.g. on the ground prior to takeoff), and natural convection of the EEC unit  26  occurs. The heat produced by the EEC unit  26  causes heated air to pass through a chimney  38  of the EEC unit  26 , thereby drawing air through the cooling duct  30  and the valve  28 . In a second mode of operation, the engine  24  is operating and producing a pressure level at the nozzle end of the duct  30  that causes air to be sucked into the chimney  38 , thus passing through the EEC unit  26  to the valve  28  and out the port  36  of the duct  30 . The second mode of operation includes, for example, ground idle, taxi, takeoff, and climb.  
         [0019]     At a third mode of operation, the aircraft is at altitude or in a cruise mode. In this mode of operation, a pressure build-up at the intake of the engine  24  forces air through the duct  30  to the valve  28 , causing the valve  28  to close and prevent cooling air from passing through the EEC unit  26 .  
         [0020]      FIGS. 2-5  illustrate various views of an embodiment of the valve  28 . As shown in  FIGS. 2 and 3 , the valve  28  includes a housing  40 . The housing  40  includes a nozzle  50  at each end with sides or side panels  44  that are mounted to opposing sides of a housing  40 . The side panels  44  preferably are clear windows that allow maintenance personnel to perform visual analysis of the inner components. The panels  44  may be opaque material or a clear material, such as high-tempered glass, polycarbonate, polyphenyl or other clear material having heat resistive properties, such as Radel®, Ultan®, or Lexan®. The panels  44  may be attached to the sides of the housing  40  by bolt mechanisms with a gasket mounted in between or are pre-coated with silicone or some other bonding agent and then bonded to the side of the housing  40 . The panels  44  may be replaced by a permanent wall structure or may be integral into the housing  40 .  
         [0021]     Because the present invention does not include a conventional hinge, the valve  28  is less susceptible to fatigue due to high vibration levels.  
         [0022]      FIG. 4  illustrates a cross-sectional view of the housing  40 . The nozzle  50  receives the cooling duct  30  ( FIG. 1 ). The nozzle  50  expands in diameter to an inner chamber  52 . At a second end of the valve  28  is a flange  56  and a tapered chamber  58  that is located between the inner chamber  52  and an opening within the flange  56 . The flange  56  is fastened by either bolts or some other fastening mechanism to an air intake portal (not shown) of the EEC unit  26 . An upper portion of the inner housing  52  is formed by a curved wall. A bottom portion of the inner cavity  52  is formed by a substantially flat base. The walls of the cavity  52  connect the nozzle  50  and the tapered cavity  58 .  
         [0023]     Mounted within the inner housing  52  is a flapper  66 . In one embodiment, the flapper  66  is substantially U-shaped and includes a first flapper section  68  coupled to a bendable portion  70 . In this embodiment, the bendable portion  70  includes a convoluted device. The bendable portion  70  is attached to a base section  74  and the base section  74  is connected to a stopper section  76 . The bendable portion  70  allows the flapper section  68  to move between the stopper section  76  to being seated between the base of the inner cavity  52  and the tapered cavity  58 , thereby blocking airflow between the inner cavity  52  and the tapered cavity  58 . The base section  74  is attached to the base wall of the inner cavity  52  by a fastening method or by a bolt mechanism.  
         [0024]     In a presently preferred embodiment, the flapper  66  is formed of a material that provides negligible hysteresis and can operate at extreme temperatures. In one embodiment, the valve material is a silicon coated fiberglass material, such as a multi-layered silicon treated fiberglass cloth. The sections of the flapper  66  exhibit different levels of flexibility. For example, the bendable portion  70  must have a certain level of flexibility while the stopper section  76  and base section  74  require a greater degree of stiffness. Various hardeners, such as resins, may be added to portions of the flapper  66  in order to provide greater stiffness. The flapper  66  may be manufactured by layering together long sheets of silicone coated fiberglass, placing the sheets in a mold, and curing the sheets under pressure and temperature in order to form the flapper  66  as desired. The sheets may be cut before or after molding. The bendable portion  70  and the weight of the flapper section  68  are adjusted in order for the flapper section  68  to be opened and closed at the proper times of operation.  
         [0025]      FIG. 4  illustrates an approximate position of the flapper  66  during the first and second modes of aircraft operation described above. In other words, the flapper section  68  is open or is resting on the stopper section  76 , thereby allowing airflow to pass in either direction through the valve  28 .  
         [0026]      FIG. 5  illustrates a position of the flapper section  68  during the third mode of aircraft operation.  FIG. 6  illustrates the flapper  66  in a full open position.  FIG. 7  illustrates the flapper  66  in a neutral position. As best shown in  FIG. 5 , in the third mode of operation, a threshold amount of airflow received by the nozzle  50  forces the flapper section  68  to a closed position. In one embodiment, the flapper section  68  is aerodynamically curved at an end in order to catch or release the proper amount of air, thus opening or closing at desired times. It will be appreciated that the flapper section  68  advantageously moves automatically in response to pressure differentials through the housing  40  during various modes of operation. Therefore, unlike conventional hinged valves, there is no need for control mechanisms to control the position of the flapper section  68 .  
         [0027]     The flapper  66  may be mounted within the inner chamber  52  such that the fail safe position is an open position. Thus, if the flapper  66  fails, the airflow through the valve device  28  will preferably not be blocked.  
         [0028]     While preferred and alternate embodiments of the invention have been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of these preferred and alternate embodiments. Instead, the invention should be determined entirely by reference to the claims that follow.

Technology Category: y