Abstract:
A diverter valve with a shutoff feature for usage in an aircraft environmental control system is disclosed. The valve has a housing that includes an inlet connected with a source of air, and first and second outlets spaced 90° apart. The first outlet is connected with the ECS refrigeration pack, while the second outlet, which is at a 90° angle with respect to both the inlet and the first outlet, is connected with a bypass line that bypasses the refrigeration pack and is connected with a heater inside the ECS. A gate internal to the valve housing is rotatable over a 90° range of motion to connect the air from the source to either solely the first outlet, to both the first and second outlets, to solely the second outlet, or to neither the first nor second outlets, depending upon a desired temperature of the air provided to the cockpit or cabin of the aircraft.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to valves, and more particularly to a diverter valve that selectively connects an input fluid flow to none, one or both outputs of the valve, depending upon the rotational position of an internal gate within the valve. 
     In the art of environmental control systems (&#34;ECSs&#34;) for controlling air quality characteristics of air provided to the cockpit and passenger cabin of an aircraft, it is known to use air supplied by a source such as an auxiliary or secondary power unit. The source air may then be controllably routed to a refrigeration pack for cooling. If heating of the air is desired, a portion or all of the source air is controllably routed around the refrigeration pack in a bypass line to a heater. The heated air may then be mixed with the cooled air to achieve conditioned air of a desired temperature. 
     In the prior art of aircraft temperature control systems described above, it is known to use dual valves to accomplish the appropriate routing of the source air between the heater and the refrigeration pack. For example, it is known to use two butterfly valves powered by a single actuator, either electric or pneumatic. The valves are linked to the actuator through a linkage mechanism. The desired temperature schedule of valve area versus actuator angle is typically obtained through design of a mechanical linkage. However, the linkage design tends to be somewhat complicated, and the mechanical linkage tends to wear over time. Also, no means is typically provided with such design to selectively shut off the air flow entirely from the source to both the refrigeration pack and the heater at the same time. An additional shutoff valve placed upstream of the dual valve may be used to shut off the air flow. 
     Accordingly, it is a primary object of the present invention to overcome the shortcomings of the prior art and to provide a single valve that can selectively divert the source air between the refrigeration pack and/or the heater, and selectively shut off the source air entirely from entering both the refrigeration pack and the heater. 
     It is a general object of the present invention to provide a single diverter valve that eliminates the need for complex mechanical linkages that wear out over time. 
     It is another object of the present invention to provide the single diverter valve that is more reliable than prior art, dual valve designs. 
     It is yet another object of the present invention to provide the single diverter valve that is smaller, more compact and lighter than prior art dual valve designs, and makes installation easier due to fewer connections and elimination of certain mounting means needed for prior art designs. 
     It is still another object of the present invention to provide the single diverter valve that controls the air temperature of an aircraft cockpit and cabin by, for example, mixing the cooling air and the heating bypass air together. 
     The above and other objects and advantages of this invention will become more readily apparent when the following description is read in conjunction with the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     To overcome the deficiencies of the prior art and to achieve the objects listed above, the applicant has invented a diverter valve with a shutoff feature. 
     In a preferred embodiment for usage in a temperature control system for an aircraft ECS, the valve has a housing with an inlet connected to a source of air, such as a secondary power unit. The valve housing also has two outlets spaced 90° apart. A first outlet is coaxial, or &#34;in-line&#34;, with the valve inlet, and is connected with an inlet of an ECS refrigeration pack. A second outlet is at a 90° angle with respect to each of the inlet and the first outlet. The second outlet is connected with a bypass line that bypasses the refrigeration pack and, instead, may be connected with a heater in the ECS. 
     Within the valve housing is disposed a hollow, ball-type, rotatable gate that comprises a sphere with two holes or orifices cut into the sphere surface, wherein the hole planes are parallel to each other. Source air flow can pass through the holes in the gate and into one or both outlets, depending upon the rotational position of the gate. The rotational gate position may be controlled by the ECS control system. In the alternative, the gate may be rotated to another position where no source air can flow into either outlet due to neither gate orifice being aligned with the inlet. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram illustration of a temperature control system for an aircraft utilizing the valve of the present invention; 
     FIG. 2 is a cross-sectional illustration of the valve of the present invention shown in a fully closed position; 
     FIG. 3 is a cross-sectional illustration of the valve of FIG. 2 shown in a fully open position; 
     FIG. 4 is a cross-sectional illustration of the valve of FIGS. 2 and 3 shown in a partially open position; 
     FIG. 5 is a perspective view of the gate portion of the valve of FIGS. 1-4; and 
     FIG. 6 is a graph illustrating the relationship between the effective area of the openings in the gate versus angular rotational position of the gate. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings in detail, a diverter valve in accordance with the present invention is described and illustrated therein and generally designated by the reference numeral 100. With specific reference to the block diagram of FIG. 1, there illustrated is the valve 100 as utilized in an exemplary embodiment of a temperature control system 104 for an aircraft. In such a system, high temperature compressed air is typically provided by an auxiliary or secondary power unit (SPU) 108. The air from the SPU 108 is fed to the valve 100 of the present invention, which then directs the flow of the compressed air to the remainder of the temperature control system 104. Typically, the temperature control system 104 also includes a refrigeration pack 112 for cooling the compressed air, together with a bypass line 116 that feeds the compressed air around the refrigeration pack 112 to a heater 120, for conditioning the air before passing it on to the cockpit and/or cabin 124 of the aircraft. The temperature of the cockpit/cabin is monitored by the ECS controller 118, which electrically governs the valve position to maintain the desired temperature. The temperature control system 104 may be somewhat similar in certain respects to that described and illustrated in U.S. Pat. No. 5,461,882, which is hereby incorporated by reference. 
     Referring now to FIGS. 2-4, there illustrated are three cross-sectional views of the valve 100 of the present invention. The valve 100 comprises, in an exemplary embodiment, an aluminum housing 128 having an inlet 132 connected to the SPU 108. The valve also has a first outlet 136 (i.e., bypass outlet) connected to the bypass line 116, and a second outlet 140 (i.e., cooling outlet) connected to the refrigeration pack 112. The valve inlet 132 is aligned, or co-axial, with the second valve outlet 140. Also, the first valve outlet 136 is disposed at a 90° angle with respect to both the valve inlet 132 and the second valve outlet 140. 
     The valve 100 also contains a gate 144 located internal to the valve housing and also formed of aluminum. As seen in better detail in FIG. 5, the gate 144 has a spherical-shaped sidewall 148, flat top and bottom surfaces, and a hollow inside. First and second holes or orifices 152, 156 are formed in the gate sidewall 148. In a preferred embodiment, both orifices 152, 156 are formed as planar &#34;cuts&#34; that are in parallel planes to each other. Also, in a preferred embodiment, the diameters of the two orifices are equal. However, for reasons that will become apparent hereinafter, the first or input orifice 152 is somewhat elongated at one end (relative to the second orifice 156) by having a portion of the orifice 152 being cut in a plane that is at an angle with respect to the parallel plane that makes up the majority of the input orifice 152. 
     The gate 144 is mounted inside the housing 128 using bushings (not shown). The gate 144 is rotatable over a 90° range of motion, in a preferred embodiment. Rotation of the gate may be controlled in a known manner by the ECS controller 118 of FIG. 1 through appropriate mechanical or pneumatic actuation of the gate by connection to a stem 160 emanating from both the top and bottom surfaces of gate 144. Also, in a preferred embodiment, the valve inlet 132 and the second valve outlet 140 both have a diameter of two inches, while the first valve outlet has a diameter of 1.5 inches. 
     The valve inlet 132, the first valve outlet 136 and the second valve outlet 140 each have mounted therein a gate seal 164, and an associated seal ring 168 and a compression spring 172. These cylindrical seals 164 are used to control the flow of air through the orifices 152, 156 in the gate 144. No air flow is allowed to pass through the gate 144 unless it is directed through the seals 164. The seals 164 are spring-loaded to maintain contact with the gate 144 under all operating conditions. The seal 164 and the seal ring 168 may comprise a plastic material, such as that provided by DuPont and marketed under trademark Vespel®. 
     Referring back to FIG. 2, there illustrated is a rotational position of the gate 144 within the valve housing 128 such that no inlet air flow is allowed to pass through either the first or second valve outlets 136, 140. With reference also to FIG. 6, this fully-closed valve position corresponds to the graph of FIG. 6 where the rotation of the gate 144 is at 90°. FIG. 6 illustrates valve airflow schedule in terms of effective area versus angular gate rotation for both the first valve outlet 136 and the second valve outlet 140. The first valve outlet 136 is illustrated by the graph designated by the reference numeral 176. The second valve outlet 140 is illustrated by the curve of FIG. 6 designated by the reference numeral 180. FIG. 2 illustrates the fully-closed position of the gate 144 that corresponds to the 90° angular rotation of the gate position on the graph of FIG. 6. From FIG. 6, it can be seen that, at 90° angular gate rotation, there is no air flow through the inlet 132 to either of the first or second outlets 136, 140. This is because the gate has blocked all flow from going beyond the inlet 132. 
     FIG. 3, on the other hand, illustrates a fully-opened position of the gate 144 within the valve housing 128 such that all of the air flow passes through the inlet 132 and through both the first and second orifices 152, 156 in the gate 144 and on to the second outlet 140 to the refrigeration pack 112. This is illustrated in FIG. 6 at the 0° angular gate rotation position. From the curve 180 of FIG. 6, it can be seen that the effective valve area for the second outlet 140 is at a maximum, while from the curve 176 the effective valve area for the first outlet 136 is at a minimum. The net effective area of the gate for the second outlet 140 is a known mathematical function of the combination of the area of the inlet 132 and the area of the second outlet 140. On the other hand, the net effective area of the first or bypass outlet 136 is a similar known mathematical function of the combination of the area of the inlet 132 and the area of the first outlet 136. 
     In contrast, FIG. 4 illustrates a 45° angular gate rotational position in which a portion of the air flowing into the inlet 132 goes into both the first and second outlets 136, 140. This is the approximate intersection point of the two curves 176, 180 of the graph of FIG. 6. 
     From the figures it can be seen that inlet air flows through the orifices 152, 156 in the gate 144, wherein these orifices are sized to yield the proper flow area versus valve angle for any particular embodiment. At a valve angle of 0° (FIG. 3), the air flow through the valve 100 is straight through the housing 128 and the gate 144, thereby providing full cooling flow of the inlet air to the refrigeration pack 112. There is no bypass flow at this position. 
     As the gate is rotated counter-clockwise with respect to FIGS. 2-4, the valve angle of rotation increases from 0°, thereby decreasing the cooling flow to the second outlet 140. At an angle of 20° of counter-clockwise gate rotation, the second orifice 156 in the gate 144 allows some of the inlet flow to pass into the first outlet 136. Up until this angle of 20°, there is no bypass flow. Thus, some refrigeration pack cooling flow throttling is allowed between 0° and 20° of counter-clockwise gate rotation. 
     As the valve angle continues to increase with increasing counter-clockwise gate rotation, the flow into the second or cooling outlet 140 continues to decrease, whereas the flow into the first or bypass outlet 136 continues to increase, providing temperature control illustrated in the graph of FIG. 6. With increasing gate rotation in a counter-clockwise rotation, a full bypass condition is reached at a valve angle of approximately 55°. Then, at approximately 70°, the flow to the second or cooling valve outlet 140 is shut off and there is only a small amount of flow to the first or bypass outlet 136. At a valve angle of 80°, the valve is essentially closed, and there is no flow from the inlet 132 to either of the first or second outlets 136, 140. The valve is essentially &#34;shut-off&#34; between valve angles of 80° and 90°. 
     However, upon clockwise rotation of the gate 144 starting from the fully-closed position of FIG. 2, it can be seen that the portion 162 of the first orifice 152 that is angled with respect to the major parallel plane of that orifice 152 allows for the characteristic curve 176 of FIG. 6 wherein there is air flow to only the first outlet 136 between valve angles of 80° and 70°. Thus, this angled portion 162 selectively allows airflow to one but not both outlets. TABLE 1 gives representative effective areas of the inlet 132, the first or bypass outlet 136, and the second or cooling outlet 140. 
     
                       TABLE 1______________________________________VALVE FLOW AREASVALVE COOLING OUTLET BYPASS OUTLET                             INLETANGLE AREA (IN.sup.2)                AREA (IN.sup.2)                             AREA (IN.sup.2)______________________________________ 0.0° 2.600          0.000        2.60010.0° 2.507          0.000        2.60020.0° 2.030          0.061        2.19330.0° 1.510          0.061        1.70440.0° 1.012          0.124        1.21550.0° 0.577          0.372        0.76160.0° 0.238          0.706        0.37770.0° 0.028          1.070        0.09980.0° 0.000          1.327        0.00090.0° 0.000          1.327        0.000______________________________________ 
    
     It should be understood from the foregoing that merely an exemplary embodiment of the valve of the present invention has been disclosed for usage with the temperature control system 104 for an aircraft. The valve 100 of the present invention finds numerous and countless other usages in many other different types of industries. Also, it should be understood by 40 those of ordinary skill in the art that the 90° range of valve rotation is purely exemplary. Instead, the amount of rotation can be either greater than or less than 90°, depending upon the particular application. 
     Further, it should be understood that providing a hollow gate with two orifices formed therein, wherein one of the orifices is elongated and has an angled portion with respect to the major plane of the orifice, are all purely exemplary. Still further, the sizes and areas of the inlet and outlet openings, together with the materials comprising all of the components, are all purely exemplary. 
     It should be understood by those skilled in the art that obvious structural modifications can be made without departing from the spirit of the invention. Accordingly, reference should be made primarily to the accompanying claims, rather than the foregoing specification, to determine the scope of the invention.