Abstract:
A variable orifice valve provides a changing orifice dimension based solely upon the temperature or other property of the fluidic medium, such as flow-rate of the fluidic medium passing through the valve, and is actuated via a thermally active wire or flow-rate activated spring, for example, immersed in the fluidic medium.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates generally to valves, and more particularly to a variable orifice valve that regulates a flow rate through the valve based upon a property of the fluidic medium, such as, for example, but not limited to its temperature or flow rate, passing through the valve.  
         [0003]     2. Description of the Prior Art  
         [0004]     Modern electronic systems and devices often require cooling to maintain their operational efficiency. Further, many of these systems and devices are extremely large requiring that only sections or portions of these systems or devices remain operational at any given moment in time. Such systems and devices therefore will require cooling of only the sections or portions that are operational.  
         [0005]     Present cooling techniques employ a tank or supply area to receive the return fluid from a cooling system by means of free flow. Such techniques therefore are not efficient since they do not allow direct control of differential flow of cooling fluid into areas of greater need, except by direct valving or orifice control.  
         [0006]     Consider for example, an array  100  having four sections such as shown in  FIGS. 1A, 1B  and  1 C. In  FIG. 1A , array  100  can be seen to exhibit section temperatures of 50° F. and 200° F. in the upper two sections from left to right respectively; while the lower two sections exhibit section temperatures of 60° F. and 50° F. from left to right respectively. Consider now also a convective cooling system: If a conventional uniform cooling approach is utilized to cool the array  100 , only 25% of the coolant may come into contact with the hot 200° F. area, quickly reaching the maximum heat flux of the cooling system. Thus, as seen in  FIG. 1B , the hot 200° F. area may cool down to only 150° F. Although better, the efficiency of uniform cooling falls short of the desired results. Consider now instead, a cooling system that directs 75% of the coolant fluid through the hot 200° F. zone, with the remaining 25% used for the other zones. Such a cooling system can be expected to extract heat more effectively. Smart cooling therefore, results in a more efficient transfer of thermal energy to yield the array temperatures depicted in  FIG. 1C .  
         [0007]     In view of the foregoing background, it would be extremely beneficial and advantageous to provide a system component such as a valve that operates in response to a fluidic medium temperature, thus allowing direct control of differential flow of cooling fluid into areas of greater need to enable gracefully enhanced cooling or heating of highly thermally disparate parts.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention is directed to a variable orifice valve that will provide a changing orifice dimension based upon, for example, the temperature or flow rate of the fluidic medium passing through the valve, and that is actuated, for example, via a thermally active wire immersed in the fluidic medium. Since the variable orifice valve provides a changing orifice dimension based upon the fluidic medium temperature, the flow rate of the fluidic medium is thermally regulated in a manner that allows greatly enhanced cooling or heating of highly thermally disparate systems or devices. Further, the variable orifice valve changes the orifice dimension via insertion of a tapered plunger element in contradistinction with known valves that employ a shutter type mechanism to modify a flow rate through the valve. This will result in less fluidic disruption than that produced by a shutter type valve, as a toroidal orifice allows flow similar to an open orifice in nature. Thus, less turbulent flow is introduced.  
         [0009]     One embodiment of the variable orifice valve employs a valve body having a fixed cross-sectional flow area; a variable cross-sectional flow area; and a movable element that operates to modify the resultant cross-sectional flow area of the variable cross-sectional flow area, to control the rate of fluidic flow through the valve. The movable element is most preferably a tapered plunger attached to a thermal wire spring. The thermal wire spring is attached such that it operates in response to the fluidic temperature to move the tapered plunger toward or away from the variable cross-sectional flow area as the fluidic temperature rises and falls, thus modifying the fluidic flow through the valve. Other types of activation means can just as easily be employed, such as, for example, but not limited to, a flow-rate activated spring mechanism.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     Other aspects, features and advantages of the present invention will be readily appreciated as the invention becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing figures wherein:  
         [0011]      FIG. 1A  depicts a system or device array having four distinct heat/cool zones;  
         [0012]      FIG. 1B  shows the temperature effects of uniform cooling applied to the distinct heat/cool zones depicted in  FIG. 1A ;  
         [0013]      FIG. 1C  shows the temperature effects of smart cooling applied to the distinct heat/cool zones depicted in  FIG. 1A ;  
         [0014]      FIG. 2  is a simplified system diagram illustrating a self-regulating cooling system;  
         [0015]      FIG. 3  is a more detailed view of the return manifold depicted in  FIG. 2 ; and  
         [0016]      FIG. 4  illustrates a variable orifice valve according to one embodiment of the present invention.  
     
    
       [0017]     While the above-identified drawing figures set forth particular embodiments, other embodiments of the present invention are also contemplated, as noted in the discussion. In all cases, this disclosure presents illustrated embodiments of the present invention by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this invention.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     Looking now at  FIG. 2 , a simplified block diagram illustrates a self-regulating cooling/heating system  200 . Self-regulating cooling/heating system  200  operates to cool or heat selected portions  212 ,  214 ,  216 ,  218 ,  220  of a radar array  210 . Each portion  212 - 220  of the radar array  210  is cooled or heated independently of any other portion as now described below. Self-regulating cooling/heating system  200  can be seen to include a return manifold  300  having a plurality of input ports  302 ,  304 ,  306 ,  308 ,  310 . Each input port  302 ,  304 ,  306 ,  308 ,  310  is connected to a single unique portion or section  212 ,  214 ,  216 ,  218 ,  220  of the radar array  210 . Manifold  300  can be seen to also have a single output port  322 . Cooling/heating system  200  has a heat transfer device such as a heat exchanger, that operates to cool or heat the coolant or heating medium that is employed to cool or heat the sections of the radar array  210 . Any suitable coolant or heating medium such as a liquid medium, gaseous medium, or coolant/heating medium, such as, but not limited to Freon, that changes state in response to temperature changes, can be employed, so long as the desired heat transfer characteristics are achieved. The heat exchanger has a single input port that receives coolant/heating medium from the single output port  322  of the manifold  300 . Subsequent to cooling or heating, the coolant or heating medium is exhausted via a single heat exchanger output port wherein the coolant or heating medium is redirected back to any coolant/heating medium input port(s) associated with the radar array  210 .  
         [0019]     Looking now at  FIG. 3 , each of the return manifold  300  input ports  302 ,  304 ,  306 ,  308 ,  310  can be seen to most preferably employ a passive self-regulating thermal gate  312 ,  314 ,  316 ,  318 ,  320 . Each passive self-regulating thermal gate  312 - 320  most preferably comprises a variable orifice valve in which the orifice increasingly opens or closes in response to changes in the temperature of the fluidic medium passing through the thermal gate. In this manner, each variable orifice valve will continue to successfully operate, even in the absence of any type of active control, such as that which may be provided via a computerized control unit or system. Each self-regulating thermal gate may however, be passively controlled or controlled via an active controller. Passive control is most preferred, since the passive, self-regulating thermal gate will continue to function in its normal temperature sensing mode to control the size of the variable orifice regardless of whether the control system or device remains operational.  
         [0020]      FIG. 4  illustrates a variable orifice valve  400  according to one embodiment of the present invention. Variable orifice valve  400  is suitable for use as one or more of the thermal gates  312 - 320  described herein before with reference to  FIGS. 2 and 3 . Variable orifice valve  400  can be seen to include a thermal sensing wire spring  402  that is attached to the valve body via a fixed pin  410  or other suitable means at one end. The other end of the thermal sensing wire spring  402  is attached to one end of a tapered plunger element  404 . The other end of the tapered plunger element  404  includes a guide element  408 . Movement of guide element  408  is controlled via a guide mount  406 . Variable orifice valve  400  can further be seen to have a fixed cross-sectional flow area  412  and a variable cross-sectional flow area  414 .  
         [0021]     As a fluidic medium passes through the variable orifice valve  400 , it comes into contact with the thermal wire spring  402 . Thermal wire spring  402  will contract or expand, thus altering its length in response to the temperature of the fluidic medium. The fluidic medium may comprise a liquid, gas, or medium that changes state or undergoes a phase transition in response to changes in temperature. As the length of the thermal wire spring  402  changes, the tapered plunger element  404  will move further into or out of variable cross-sectional flow area  414 , thus modifying the resultant cross-sectional flow area of the variable cross-section flow area  414 . As the tapered plunger element  404  moves further into the variable cross-sectional flow area  414 , the resultant cross-sectional flow area will be reduced to further restrict the flow of fluidic medium through the variable orifice valve  400 . As the tapered plunger element  404  moves further away or out of the variable cross-sectional flow area  414 , the resultant cross-sectional flow area will be increased to allow greater flow of fluidic medium through the variable orifice valve  400 . The path of movement of the tapered plunger element  404  is strategically controlled via a sliding motion of guide element  408  as it passes through the guide mount  406 .  
         [0022]     In summary explanation, the return fluid from a cooling system is typically returned to a tank or supply area by means of free flow. This does not allow direct control of differential flow of cooling fluid into areas of greater need in enclosures and the like except by direct valving or orifice control. Self-regulating action is thus not allowed to take place. If the free flow of the fluid was controlled by means of a thermally operated variable orifice valve, the variable orifice valve would increase the back pressure on the cooling system for those fluid paths not requiring as much cooling. This would force additional cooling fluid across the fluid paths of free flow, resulting in a greater cooling of those paths requiring more heat removal. This would be controlled by the temperature of the fluid passing through the thermally operated variable orifice valve. The foregoing variable orifice valve provides a self-regulating capacity not presently available in the industry without expensive flow control feedback systems. A system using such a valve will, in contradistinction with presently available systems, most preferably operate passively and accomplish the same result. Although an embodiment has been described with reference to a thermally acting spring, the present invention is not so limited; and it shall be understood that a flow-rate activated spring or other type of spring activation means could also be employed to implement other embodiments according to the principles of the invention described herein before.  
         [0023]     In view of the above, it can be seen the present invention presents a significant advancement in the art of valve design. Further, this invention has been described in considerable detail in order to provide those skilled in the heat transfer arts with the information needed to apply the novel principles and to construct and use such specialized components as are required.  
         [0024]     It should be apparent that the present invention represents a significant departure from the prior art in construction and operation. However, while particular embodiments of the present invention have been described herein in detail, it is to be understood that various alterations, modifications and substitutions can be made therein without departing in any way from the spirit and scope of the present invention, as defined in the claims which follow. The tapered plunger element, for example, may employ any number of different three-dimensional geometric configurations, so long as it operates to modify the resultant cross-sectional area in accordance with the principles described herein before.