Abstract:
A plural function, three member, fluid valve includes a stationary base member which provides plural fluid ports connected to apparatus requiring or providing fluid control, a first movable member containing conduits which are selectively movable into alignment with the ports of the base member to select the function(s) to be performed, and a second movable member having a U-shaped passageway for selectively connecting passageways of the first member to execute the selected function, i.e., to form a fluid conduit from one port of the base member through a conduit in the first member, the U-shaped passageway in the second member and a second conduit in the first member to another port in the base member. Methods are also disclosed.

Description:
This application claims the benefit of U.S. Provisional Application Ser. No. 60/051,759 filed Jul. 7, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to fluid control valves and more particularly to three part valves and methods. 
     Fluid control valves to direct the flow of fluid, liquid or gas, are well known, and it has long been desirable to provide a valve capable of performing multiple functions. The typical multi-function fluid valve is of the linear displacement spool type consisting of a spool with several fluid inlet and outlet ports, each having a seating surface. Such known valves are capable of performing multiple functions by simultaneously or sequentially establishing various fluid flow paths through the spool. However, the number of functions performed by such valves is limited by the complexity of the valve construction and the physical size of the valve. Additionally, such valves requires a large number of precisely machined parts and seals, and maintenance and repair is generally costly. 
     Rotary valves are also well known and have fewer moving parts than spool valves. Typically, a rotor having a U-shaped passageway is rotated with respect to a ported surface of a valve body to interconnect various ports of the valve body through the rotor. Such valves may be two function valves, i.e., they may selectively connect one input port to one of two output ports, or vice versa. More complex rotary valves can simultaneously route more than a single fluid stream to various destinations by use of a more than one U-shaped passageway in the rotor. 
     Because rotary valves establish a flow path by aligning the channel of the rotor with selected ports of the stationary member and did not have cut-off valves within the rotor passageways, care had to be taken to ensure that non-selected ports were not “inadvertently” connected by rotation of the rotor relative to the stationary member. This limited the use of such valves to multiple functions carried out in a predetermined sequence. 
     The present invention obviates the need for use of a separate cutoff valve to prevent “inadvertent” flow paths from being establish by using a rotary valve having two movable members. Additionally, the use of two movable members increases the number of functions that can be performed by the valve. In the present invention, the first member selects the fluid function to be executed by aligning non-connected conduits with the selected ports. The second member can then execute the selected function by connecting the two conduits thereby establishing a fluid flow path between the selected ports through the first and second member. 
     Accordingly, it is an object of the present invention to obviate many of the limitations of known valves and to provide a novel multiple function fluid valve and method. 
     It is another object of the present invention to provide a novel valve and method capable of selecting one of several functions and then selectively executing the selected function. 
     It is another object of the present invention to provide a novel valve and method of connecting selected ports to establish a fluid communication path. 
     It is yet another object of the present invention to provide a novel plural function valve and method having separate moving members to select and then execute the desired function. 
     It is still another object of the present invention to provide a novel valve and method for performing complex fluid functions. 
     These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified exploded view of one embodiment of a plural function, rotary fluid valve of the present invention. 
     FIGS. 2 a - 2   c  are a second embodiment of a plural function linear fluid valve of the present invention. 
     FIG. 3 is a simplified exploded view of an application of the valve of FIG.  1 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to FIG. 1 where one embodiment of the valve of the present invention is illustrated, the valve comprises a stationary base  100  and first and second rotors  110  and  120 . 
     The base  100  may contain plural conduits  101  each having a port on the upper surface  103  thereof and being connected at the other end to a suitable apparatus (not shown) requiring or providing fluid control. Each of the ports on the surface  103  of the base may be provided with a suitable conventional sealing means  105  to prevent fluid leakage from the conduits  101  as the first rotor  110  is rotated relative to the base. The sealing means  105  preferably are self-lubricating so as not to impede the relative rotational movement between first rotor  110  and the base  100 , and the force exerted by sealing member may be a function of the resilient means used to construct the seal or the pressure of the fluid sealed. Alternatively, the smoothness of the adjacent surfaces and the spacing between them may be sufficient to prevent leakage of the fluid from the ports. 
     The first rotor  110  is located adjacent to the base  100  and may contain plural conduits  111  passing from the lower surface  112  to the upper surface  116  thereof. The conduits  101  of the base  100  and the conduits  111  of first rotor  110  are positioned such that any conduit  111  of the first rotor  110  may be aligned with any selected conduit  101  of the base  100  by the rotational movement of first rotor  110  about the central valve axis provided by the pin  115 . The ports for the conduits  111  on second surface  116  may be provided with a suitable conventional seal  105 . 
     The second rotor  120  may contain plural U-shaped passageways  121  each having ports located on the lower surface  122  thereof. The passageways  121  are positioned to be selectively aligned with the ports of pairs (or larger groups) of conduits  111  in the lower rotor  110  by rotation of the upper rotor  120  relative thereto. 
     One or both of the rotors  110  and  120  may contain any suitable conventional biasing means  117 , 119  such as a spring biased detent for interconnecting the two rotors  110 ,  120  with a predetermined bias so that the first rotor, when driven in any suitable conventional manner such as the stepper motor  118  and drive  123  shown, may rotate both of the rotors  110 ,  120  as a single unit. 
     The upper rotor  120  may also be driven by any suitable conventional means such as the stepper motor  124  and drive  125  shown, the drive for the upper rotor  120  desirably being disengaged during the rotation of the lower rotor  110  to permit rotation of both rotors by the drive for the lower rotor  110 . Rotation of the upper rotor  120  relative to the lower rotor  110  despite the bias provided by the latch  117 , 119  may be accomplished by engaging the drive for the upper rotor  120  while leaving the drive for the lower rotor  110  engaged. 
     It is to be understood that the rotors  110  and  120  may be driven by a toothed pinion gear, friction or belt drives, etc. and that rotary or linear solenoids or other mechanical, pneumatic, fluid, electrical or electromechanical devices may be substituted for the stepper motors illustrated. 
     In operation, a FUNCTION SELECT control signal may be applied to the motor  118  to rotate the lower rotor  110  so as to align the desired one or more of the conduits  111  of the lower rotor with selected ports  101  of the base  100 . The upper rotor  120  may be coupled to lower rotor  110  such that the upper rotor rotates with the selective positioning of the lower rotor  110  by motor  118 . 
     When the conduits  111  of the lower rotor are aligned with the selected conduits  101  of the base  100  as determined by the FUNCTION SELECT control signal, a FUNCTION EXECUTE control signal may be applied to the motor  124  to selectively rotate the upper rotor relative to the lower rotor  110  to align the ports of the passageway  121  in the upper rotor  120  with the ports  105  in the lower rotor  110 , thereby creating a fluid passageway between the selected ports of the base  100  through the lower rotor  110  and the U-shaped passageway of the upper rotor  120 . When fluid communication between the selected ports of the base  100  is no longer desired, an additional FUNCTION EXECUTE control signal may be used to cause motor  124  to return the upper rotor  120  to a neutral of closed position relative to the conduits of the lower rotor  110 . Alternatively, relaxation of the FUNCTION EXECUTE control signal may permit the upper rotor  120  to return to a neutral or closed position under the influence of the bias of the means  117 , 119 . 
     It should be understood that any number of functions with various complexities may be provided by the appropriate formation of passageways in the base and rotors, including the use of additional rotors as desired. 
     While rotary valves are desirable in that they do not have to be reversed to initiate a new valve cycle, the present invention may also be implemented in a linear valve such as shown in FIG.  2 . With reference to FIG.  2 ( a ), a base  200  is illustrated with two pairs of conduits  202  and  204  having ports on the upper surface surrounded by a seal  206 . A lower slide  208  is illustrated having a single pair of conduits  210  having ports on the upper surface surrounded by suitable seals  212 . An upper slide  214  is illustrated as having a single U-shaped passageway  216 . 
     Note that the upper slide  214  is maintained in its rightmost or “valve closed” position against a stop  218  by a spring  220 . Note also that the conduits  210  of the lower slide  208  are not aligned with either one of the pairs of passageways  202  or  204  of the base  200 . 
     The position of the lower slide  208  relative to the base  200  may be controlled by means mounted on the base  200  in any suitable conventional way, e.g., the spring  220  and solenoid or pneumatic piston  222  used to control the position of the upper slide  214  relative to the lower slide  208 . Note that the motive force for the piston may be provided by the fluid being controlled. 
     In FIG.  2 ( b ), the lower slide  208  has been moved to align the conduits of the lower slide  208  with the conduits  202  of the base  200 , it being understood that the conduits  210  of the lower slide could have been aligned with the conduits  204  of the base  200  by movement of the lower slide  208  to the right instead of to the left. 
     Note that the position of the upper slide relative to the lower slide  208  has not changed, and that while the conduits  202  of the base and  210  of the lower slide have been aligned, no fluid can flow therethrough. 
     As shown in FIG.  2 ( c ), the upper slide  214  has been moved to the left by the actuation of the solenoid  222  against the bias of the spring  220 , positioning the ports of the U-shaped passageway in alignment with the conduits  210  of the lower slide and permitting fluid flow between the pairs of conduits  202  in the base  200 . When it is desirable to stop fluid flow, the power may be removed from the solenoid or pneumatic piston  222  to allow the upper slide  214  to return to the right under the bias of the spring  220 . Note that no movement of the lower slide  208  relative to the base  200  is required to stop fluid flow in the pair of conduits  202 . 
     An embodiment of the rotary valve of the present invention in an application to control the pneumatic brakes on a railroad car is illustrated in FIG.  3 . With reference to FIG. 3, the base  300  is provided with four conduits  302 ,  304 ,  306  and  308 , conduit  306  being connected to the air reservoir (not shown), conduit  304  being connected to the brake cylinder (not shown), conduit  308  to the brake pipe (not shown) which extends along the train and provides compressed air, and conduit  320  being vented to the atmosphere. The adjacent ones of the conduits  302 - 308  are equally spaced. 
     A lower rotor  326  is provided with a single pair of conduits  328  spaced to conform to the spacing between adjacent ones of the conduits  302 - 308 . An upper rotor  334  is also provided with a single U-shaped passageway  336  the ports of which are spaced to conform to the spacing between the conduits  328  of the lower rotor  326 . 
     To charge the air reservoir from the brake pipe, a control signal CHARGE RESERVOIR may be sent to the stepper motor  322  to rotate the pinion  324  to position the lower rotor  326  so that the conduits  328  are aligned with the ports  306  and  308  of the base  300 . Once the lower rotor  326  is correctly positioned, an EXECUTE FUNCTION control signal may be sent to the motor  330  to drive pinion  332  to rotate the upper rotor  334  to align the ports of the U-shaped passageway  336  and complete the passageway from the brake pipe port  308  through the conduit  328  and U-shaped passageway  336  back through the conduit  328  to the port  306  of the air reservoir. Once charging of the air reservoir is complete, the upper rotor may be rotated to a neutral position closing the passageway and ending the “charge reservoir” function. 
     The function of applying the brakes can be performed by the same valve by applying a APPLY BRAKE control signal to the motor  322  to position the first rotor  326  to align the conduits  326  with the base port  304  of the brake cylinder and the venting base port  302 . Once this “braking” function is selected, the upper rotor  334  can be given the FUNCTION EXECUTE control signal to align the ports of the U-shaped passageway  336  with the conduits  328  and complete the passageway from the brake cylinder port  304  through the conduit  328  and U-shaped passageway  336  back through the conduit  328  to the port  302  to atmosphere. Once the brake cylinder has been charged to the selected pressure to apply the brakes, the upper rotor  334  may be rotated to a neutral position closing the passageway and maintaining the “apply brakes” function at the selected pressure. 
     The function of releasing the brakes can be performed by the same valve by applying a RELEASE BRAKE control signal to the motor  322  to position the first rotor  326  to align the conduits  326  with the base port  304  of the brake cylinder and the base port  306  of the air reservoir. Once this “braking” function is selected, the upper rotor  334  can be given the FUNCTION EXECUTE control signal to align the ports of the U-shaped passageway  336  with the conduits  328  and complete the passageway from the air reservoir port  306  through the conduit  328  and U-shaped passageway  336  back through the conduit  328  to the port  304  of the brake cylinder. Once the charging of the brake cylinder, and the release of the brakes, is complete, the upper rotor may be rotated to a neutral position closing the passageway and ending the “release brakes” function. 
     Thus the same valve, with minimum movement between the parts, can perform multiple functions with only two control signals, i.e., a “function select” and a “execute function” signal. Additional functions may be added simply by providing additional appropriately positioned ports, which ports may be connected to the same or different sources as desired, without making any change to the upper rotor and/or without increasing the number of actuating devices. Of course, additional U-shaped or other complex channels may also be provided in the upper rotor for the simultaneous execution of plural functions. 
     While preferred embodiments of the present invention have been described, it is to be understood that the embodiments described are illustrative only and the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalence, many variations and modifications naturally occurring to those of skill in the art from a perusal hereof.