Abstract:
A slim profile rotary control valve capable of independently modulating fluids into a single heat exchanger from two different and distinct systems that utilize the same type of heat transfer fluid. The valve is capable of monitoring both the supply and return fluid temperatures as well as the mass flow to enable the valve controller to optimize system&#39;s energy efficiency. It eliminates the use of multiple valves currently used in a conventional changeover system and automated control of valve positioning works much superior to existing valves. The housing and inner cylinder have tapered profiles to enable rotary sealing between the inlet and outlet ports. The housing has flow characterization profiles machined into the outlet ports thus eliminating the need for characterization disks. The rotary valve has a geometry that allows for a no flow dead zone when no heat exchange is so demanded.

Description:
[0001]    The following application is a continuation in part (CIP) application based on the co-pending utility application Ser. No. 14/085,423 filed Nov. 20, 2013 which was a CIP based on then co-pending utility application Ser. No. 12/815,240 filed Jun. 14, 2010 (now abandoned). The following application incorporates by reference all material disclosed therein both prior applications. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a extremely versatile combined valve and flowrater that can be used in a plethora of HVAC situations including for changeover operation, heating and cooling modulation and energy monitoring and control. It provides system simplicity and energy efficiency. 
         [0003]    Current HVAC systems employ multiple heat transfer surfaces in order to recover energy, preheat, heat, cool and dehumidify the supply airflow. Each of these heat transfer devices impart air friction, and in turn consumes fan energy. By using a single heat transfer surface for heat recovery, preheat, heat and cool, there is a reduction in the quantity of devices, air friction and resultant fan energy. The current invention results in a new type of valve which can allow multiple piping systems to share the usage of a common coil. The valve will allow hot and chilled water piping systems with the same type of fluid to utilize a single heat transfer device. The valve will combine numerous functions into a single valve which has not heretofore been done. 
         [0004]    Henceforth, combined changeover and control valve combined with a flowrater would fulfill a long felt need in the HVAC industry. This new invention utilizes and combines known and new technologies in a unique and novel configuration to overcome the aforementioned problems and accomplish this. This new valve will allow buildings using hot and chilled water distribution systems to have improved efficiency especially if lowering the conventional return hot water temperature from 160 down to below 100 deg F. In air handling units, fan energy is reduced as there is only a single coil providing both the heating and cooling functions. 
       SUMMARY OF THE INVENTION 
       [0005]    The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a combined rotary valve and flowrater that is able to improve HVAC fan and heating efficiency and simplify systems by reducing the quantity of valves, heat exchangers and controls. 
         [0006]    It has many of the advantages mentioned heretofore and many novel features that result in a new and improved combined valve and flowrater which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art, either alone or in any combination thereof. 
         [0007]    In accordance with the invention, an object of the present invention is to provide an improved single combined valve and flowrater capable of providing the supply and return fluid from one of two different systems to a single coil completely independently. 
         [0008]    It is another object of this invention to provide an improved single valve and flowrater capable of modulating both the heating and cooling functions of a single coil and that has a reduced profile having an inner cylinder that rotationally can seal fluids against and within an outer cylinder having a mating configured geometry. 
         [0009]    It is a further object of this invention to provide a single combined valve and flowrater capable of providing improved temperature control of heating and cooling with a single control output accomplished by a modulating each fluid through a tapered or characterized shaped ports. 
         [0010]    It is yet a further object of this invention to provide a rotary valve and flowrater combination with a geometry that allows for a no flow dead zone when no heat exchange is so demanded. 
         [0011]    It is yet a further object of this invention to provide an improved combined valve and flowrater capable of modulating cooling and heating to a coil as well as having a supply pressure independent control and having the capability of measuring the fluid flowrate, fluid temperature to and temperature from heat exchanger, thereby allowing delivered energy to be calculated monitored and accumulated. 
         [0012]    It is another object of this invention to promote energy recovery with four pipe water to water heat pumps with a tapered or characterized flow profile that enables more precise automatic temperature adjustment without excessive operational valve movement. 
         [0013]    It is yet another object of this invention to enable computer adjustment of minimum cool, maximum cool, minimum heat and maximum heat fluid flow and low energy with a minimum of automated valve manipulation or control. Hunting and over compensation of the valve positioning as well as the attendant temperature swings should be minimized. 
         [0014]    It is yet another object of this invention to enable computer monitoring of flow and return water temperature to provide freeze management of heat exchanger. For any given heat exchanger there is a minimum flow and a minimum temperature which will indicate that heat exchanger is in danger of fluid freezing within the heat exchanger passages. 
         [0015]    It is another object of this invention to provide an improved valve and flowrater combination utilizing single port cutoff flow control such that when there is no change in the associated heat exchanger, all flows into or out of the heat exchanger are stopped. 
         [0016]    The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements. Other objects, features and aspects of the present invention are discussed in greater detail below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is an isomeric exploded perspective view of the valve and attached actuator showing the general arrangement of all components; 
           [0018]      FIG. 2  is a top view of the valve; 
           [0019]      FIG. 3  is a rear view of the valve; 
           [0020]      FIG. 4  is a front view of the valve; 
           [0021]      FIG. 5  is a side view of the valve; 
           [0022]      FIG. 6  is a rear view of the valve housing without the top plate; 
           [0023]      FIG. 7  is a perspective view of the valve cylinder; 
           [0024]      FIG. 8  is a perspective of the valve without the actuator; 
           [0025]      FIG. 9  is a top view of the valve cylinder; 
           [0026]      FIG. 10  is a rear view of the valve cylinder; 
           [0027]      FIG. 11  is a front view of the valve cylinder; 
           [0028]      FIG. 12  is a side view of the valve cylinder; 
           [0029]      FIG. 13  is a rear perspective view of the valve cylinder; 
           [0030]      FIG. 14  is a side view of the flowrater; 
           [0031]      FIG. 15  is a perspective view of the flowrater; 
           [0032]      FIG. 16  is a top view of the flowrater; 
           [0033]      FIG. 17  is a side view of the flowrater taken 90 degrees from  FIG. 14 ; 
           [0034]      FIG. 18  is a top view of the valve housing with the flowrater and valve cylinder removed; 
           [0035]      FIG. 19  is a front view of the valve housing; 
           [0036]      FIG. 20  is a perspective view of the valve housing; 
           [0037]      FIG. 21  is a side view of the valve housing; 
           [0038]      FIG. 22  is a top cutaway view of the valve with the valve cylinder rotated to the first system fluid position; 
           [0039]      FIG. 23  is a top cutaway view of the valve with the valve cylinder rotated to the second system fluid position; 
           [0040]      FIG. 24  is a top perspective cutaway view of the valve with the valve cylinder rotated to the first system fluid position; 
           [0041]      FIG. 25  is a top perspective cutaway view of the valve with the valve cylinder rotated to the second system fluid position; 
           [0042]      FIG. 26  is a bottom perspective view of the top plate; 
           [0043]      FIG. 27  is a top perspective view of the top plate; 
           [0044]      FIG. 28  is a side perspective view of the valve housing and valve cylinder; 
           [0045]      FIG. 29  is a front perspective cutaway view of the valve housing and valve cylinder showing the port designs; 
           [0046]      FIGS. 30-32  are front views of the valve housing ports with phantom views of the valve cylinder ports as the valve goes from closed no-flow position (45 degree of rotation) to fully open; (90 degree of rotation)  FIG. 33  is a top view of the valve in a closed no-flow position; 
           [0047]      FIG. 34  is a perspective view of the valve in a closed, no-flow position; and 
           [0048]      FIG. 35  is a perspective view of an alternate embodiment valve housing. 
       
    
    
     DETAILED DESCRIPTION 
       [0049]    There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting. 
         [0050]    The term “flowrater” as used herein is synonymous with the term “flow meter” and refers to a device installed into or onto piping/tubing that measure the flow of the fluid within the pipe at that point. It may just give a visual indication of the rate of flow (generally these are referred to as flowrater rotors) or it may send a signal representative of the rate of flow that is manifested into a readable value on a visual scale, meter, electronic or computer readout. 
         [0051]    The present invention is a dual chamber, tapered cylindrical valve designed for system simplicity and energy efficiency in a plethora of HVAC situations. It sees its full potential when used for changeover operation, heating and cooling modulation. Although discussed herein as a valve for use with a heat exchanger that utilizes hot and chilled water from two different systems to heat or cool the secondary side of the heat exchanger, it is known that the valve has a plethora of different applications and numerous fluids/gasses could be used in accordance therewith. For this reason what is termed herein as a heat exchanger return port and a heat exchanger supply port may also be termed a valve return port and a valve supply port as they need not be connected to a heat exchanger. Here, cold and hot fluid media from two separate and distinct fluid media systems may be each alternately introduced into a single heat exchanger and controlled/monitored efficiently and with the use of a single characterized flow valve that is able to shut off all flow to the inlet or outlet lines rather than continue valve positioning movement through a transition point wherein the flow of the inlet line must be directed to both of the hot and cold fluid media lines simultaneously. 
         [0052]    Key to the understanding of the operation of this valve is that for changeover operation in the heating or cooling of a heat exchanger, either the hot or cold fluid medium (e.g. cold water) or the second heat transfer medium (e.g. hot water) independently and alone will be circulated through the heat exchanger. These two heat transfer media come from their own independent systems (e.g. chilled water or hot water systems) but contain the same type of heat transfer fluid. Generally, to accomplish this switching of heat transfer media with the prior art technology required multiple valves, actuators and controllers. The present invention uses dual, parallel (simultaneously) operated, cylinder chambers and the chambers are not in direct fluid communication with each other. Although described herein the drawings and specification with the upper chamber designated as the return chamber and the lower chamber designated as the supply chamber, these designations may be reversed with the functional and structural features of the lower chamber and upper chamber remaining unchanged. I.E. the lower chamber could be the return chamber with the flowrater (rotor) measuring the supply flow and the housing&#39;s cold and hot water supply ports would be equilateral triangular shaped with two radiused to help characterize the supply flows 
         [0053]    Looking at  FIG. 1  the exploded general arrangement of the preferred embodiment power operated rotary valve  102  with a combined flowrater unit  110  can be seen. The rounded valve housing (body)  104  is a unitary body with a stopped, tapered, central bore  106  formed therein about its longitudinal axis to matingly engage the correspondingly tapered valve cylinder  108  and flowrater unit (rotor)  110  ( FIGS. 14-17 ). In an alternate embodiment a unitary, hexagonal valve housing  200  ( FIG. 35 ) replaces the rounded valve housing  104 . This hexagonal shape is utilized for specific condition to support different piping connections. Its operation remains unchanged from that of the rounded valve housing  104  of the preferred embodiment. Additional geometric external configurations of the valve housing may also be employed as would be well known in the art. 
         [0054]    The valve cylinder  108  is divided into an upper return chamber  124  and a lower supply chamber  122 , ( FIG. 10 ) the contents of which are directed through the heat exchanger return port  156  or the heat exchanger supply port  158  of the valve housing  104  ( FIG. 1 ) and into the supply or return lines of any connected heat exchanger. Inside this central bore  106  the flowrater unit  110  is rotationally nested inside the valve cylinder  10  (FIGS.  7  and  9 - 13 ) separated by a large bearing  112  located centrally on the top of the flowrater&#39;s central spine  114  and residing within a top detent  120  in the ceiling of the chamber  134 . The flowrater unit  110  has a smaller bearing  116  centrally located on its bottom face that resides in bottom detent  130  ( FIG. 18 ) of the valve housing  104 . Each of the spherical balls bearings  110  and  116  are spherical bearings (balls) and serve as rotational bearings to allow the flowrater unit  110  to freely rotate to indicate both the direction and magnitude of fluid flow through the return chamber  124 . The planar support plate  118  of the flowrater unit  110  has a smaller bearing  116  centrally located on its bottom face that resides in bottom detent  130  ( FIG. 18 ) of the valve housing  104 . Each of the bearings  110  and  116  are spherical bearings (balls) and serve as rotational bearings to allow the flowrater unit  110  to freely rotate to indicate both the direction and magnitude of fluid flow through the return chamber  124 . return chamber  124 . The planar support plate  118  of the flowrater unit  110  has a smaller bearing  116  centrally located on its bottom face that resides in bottom detent  130  ( FIG. 18 ) of the valve housing  104 . Each of the bearings  110  and  116  are spherical bearings (balls) and serve as rotational bearings to allow the flowrater unit  110  to freely rotate to indicate both the direction and magnitude of fluid flow through the return return chamber  124 . However it is known that other rotational bearings may be substituted for the rotational bearings  110  and  116 , including slippery polymer disks, planar bearings and other equivalent devices. 
         [0055]    Although described herein and depicted with the flowrater unit  110  having the planar support plate  118  located on its bottom face, it is known that the flowrater unit  110  may be inverted such that the planar support plate  118  resides on the top of the flowrater unit  110 . However, in that configuration the larger of the spherical bearings  112  would reside in the detent  130  of the support plate  118  which would be located at the top of the flowrater unit  110  and partially reside within the top detent  120  in the ceiling of the chamber  134 . The smaller bearing  116  would be centrally located on the bottom of the flowrater&#39;s central spine  114  and partially reside within the bottom detent  130  in the valve housing. When installed in this manner, any debris that gets to the bottom of the stopped, tapered, central bore  106  will be flushed out with the flow of fluid. Again, here each of the bearings  110  and  116  are spherical bearings (balls) and serve as rotational bearings to allow the flowrater unit  110  to freely rotate to indicate both the direction and magnitude of fluid flow through the return chamber  124 . 
         [0056]    In other embodiments the flowrater  110  may be rotationally nested inside either the upper chamber or the lower chamber of the valve cylinder in either of the orientations and configurations described above. 
         [0057]    The flowrater  110  is a circular disk with a central spine  144  from which extend radially, a series of vanes  170 . Between each vane is a void through which the passing fluid resides on its passage across the valve cylinder  108 . The passing fluid&#39;s direction and pressure on the positive displacement vanes  170  cause the flowrater to rotate (spin). The direction and magnitude of fluid flow can be signaled for remote indication through the use of a Hall Effect pickup sensor  182  with the corresponding magnet  168  which is well known in the art and not discussed further herein. 
         [0058]    This valve cylinder  108  has the physical configuration of an almost right circular cylinder bearing a slight inward or narrowing taper (approximately 1 degree) from the top to the bottom. ( FIG. 13 ) Although other cylindrical configurations are known and can be utilized such as non tapered and multiple tapered configurations or tapers with degrees other than the approximate 1 degree stated herein. It has two parallel round disks, the first disk  132  ( FIG. 7 ) that forms the ceiling of the upper return chamber  124  and the second disk  134  that forms the floor of the upper return chamber  124  and the ceiling  134  of the lower supply chamber  122   FIG. 13 ) of the valve cylinder  11 . The second disk  134  resides approximately at the longitudinal midpoint of the cylinder  108  so as to bisect the cylinder  108  into the upper return and lower supply chambers. In this way, the two chambers are of equal volume, although this need not be the case. The first disk  132  has a shaft  136  extending centrally and normally therefrom its top face as well as a valve rotation stop  138  extending normally therefrom the top face. The valve rotation stop  138  resides within an arced slot  140  in the top plate  142  and acts as a stop to limit the degrees of rotation the valve cylinder  108  can be rotated within the valve housing  104 . The shaft  136  passes through an orifice  144  formed through the top plate  142  and is designed for connection to a valve actuator  146 . ( FIG. 1 ) Sealing of leakage at this shaft/top plate interface can be accomplished by various different methods as is well known in the art and may involve a design configuration that that incorporates at least one of the following: a thrust bearing; packing; seal; shim ring; or o ring. The complimentary tapers in the design of the valve cylinder  108  and the valve housing  104  along with the selection of their materials act to seal the supply and return fluids in their respective chambers. 
         [0059]    The valve cylinder&#39;s upper chamber has a first set of ports, its lower chamber has a second set of ports, and the valve housing has a third set of ports that are sized and spaced so as to accomplish the flow directional manipulations and control set forth herein during rotation of the valve cylinder within the valve housing. 
         [0060]    As can be seen in  FIGS. 10-12 , each of the valve cylinder&#39;s chambers has two openings. In the upper return chamber  124  there is a return crossover port  152  and a return slot port  154 . In the lower supply chamber  122  there is a supply crossover port  148  and a supply slot port  150 . In the valve housing  104  there are six ports. 
         [0061]    In the top half of the housing ( FIG. 20 ) there is heat exchanger return port  156 , a cold water return port  160  and a hot water return port  166 . In the bottom half of the housing there is heat exchanger supply port  158 , a cold water supply port  164  and a hot water supply port  162 . All of these are formed through the walls of the valve housing  104  and are fitted for mechanical connections to piping/tubing. 
         [0062]    Looking at FIGS.  20  and  22 - 25 , it can best be seen that the physical location of the return crossover port  152  allows for it to align fully with either the cold water return port  160  or the hot water return port  166  within the freedom of rotation it has as defined by the valve rotation stop&#39;s allowed movement within arced slot  140 . Similarly, the physical location of the supply crossover port  148  allows for it to align fully with either the cold water supply port  164  or the hot water supply port  162  within the freedom of rotation it has as defined by the valve rotation stop&#39;s allowed movement within arced slot  140 . Similarly, the physical location of the return crossover port  152  allows for it to align fully with either the cold water return port  160  or the hot water return port  166  within the freedom of rotation it has as defined by the valve rotation stop&#39;s allowed movement within arced slot  140 . 
         [0063]    Looking at  FIGS. 30-32 , the spacing between the cold water return port  160  and the hot water return port  166  is sufficient to allow for the return crossover port  152  to reside between them so as to cut off flow from either return port. Similarly, the spacing between the cold water supply port  164  and the hot water supply port  162  is sufficient to allow for the supply crossover port  148  to reside between them so as to cut off flow to either supply port. The number of degrees of non-ported valve housing between the valve cutout regions occupied by the hot and cold water return ports and hot and cold water supply ports, allow for a no flow dead zone. This is an important feature that helps minimize valve modulation when the controller senses that no further change in temperature is necessary. This minimizes unnecessary valve positioning control from the automatic controller. (Thereby eliminating wear and tear on the valve and associated electronics.) 
         [0064]    Looking now at the  FIG. 10-12  slot ports  150  and  154  it can be seen that supply slot port  150  is of sufficient width that as the valve cylinder  108  rotates through the maximum extents of its limited rotation, supply slot port  150  remains positioned over the heat exchanger supply port  158 . Similarly, it can be seen that return slot port  152  is of sufficient width that as the valve cylinder  108  rotates through the maximum extents of its limited rotation, return slot port  154  remains positioned over the heat exchanger return port  156 . Similarly, it can be seen that return slot port  154  is of sufficient width that as the valve cylinder  108  rotates through the maximum extents of its limited rotation, return slot port  154  remains positioned over the heat exchanger return port  156 . 
         [0065]    It is important to distinguish the differences in the physical shape of the port openings between the valve cylinder  108  and the valve housing  104 . Looking at  FIGS. 29-32  it can be seen that the valve cylinder&#39;s crossover ports  148  and  152  have a generally rectangular configuration with arced parallel top and bottom sides. The valve housing&#39;s cold and hot water return ports  160  and  166  are generally square with radiused corners and are physically larger than the valve cylinder&#39;s crossover ports  148  and  152 . In this way there is minimal restriction offered by the valve housing&#39;s supply ports and the volume of coolant allowed to the heat exchanger is maximized. 
         [0066]    The valve housing&#39;s cold and hot water supply ports  164  and  162  are equilateral triangular shaped with two radiused corners. The non-radiused corners face each other. This configuration serves to help characterize the flow. It allows the flow through the valve  102  to have a more tapered response to the percentage opening of the valve and the flow of fluid through the valve (often referred to as characterizing). When a valve has radical changes in flow with a small opening, that valve has greatly reduced its usefulness for control applications. Characterizing the supply ports of the valve so that it has close to an equal percentage characteristic ensures good stability of control. This type of characteristic produces a linear variation in thermal output according to the amount of opening of the valve. The increase in flow as the valve is opened is very slow and controlled. This produces better part-load behavior and improved stability of control while also optimizing energy consumption. Because of this design, there is no need for a separately installed flow restricting orifice or characterization disk to customize the flow response to match a more linear heat transfer result. 
         [0067]    From  FIG. 18  and  FIG. 28 , about the periphery of the valve housing  104  there are a series of threaded orifices  168  that align with a series of orifices  170  in the top plate  142  so as to allow threaded engagement between screws/bolts  172  which pass through orifices  170  and threadingly engage threaded orifices  168  to affix the top plate  142  to the valve housing  104 . 
         [0068]    About the exterior sides of the valve body  104 , all of the various ports formed through the walls of the valve body are depicted as having internal threads, however a smooth walled embodiment may be utilized when it is desirable to solder in the piping connections to the valve  102 . Alternately the pipe connections may protrude from housing to allow the use of flanged connectors or grooved connectors or clamp ring connectors or other connectors common for connecting end devices to piping. 
         [0069]    The top square section of the valve shaft  136  fits into a matingly engagable section of a valve actuator  146 . The valve actuator  146  is a commercially available rotary actuator that operates through an approximately 90 degree rotation with additional adjustment for rotary motion at each extent of its rotation travel. Such actuators and the setup and operation of the associated control logic is well known in the industry and is not the subject of further explanation her. It suffices to say that the present invention is completely compatible with the plethora of existing valve controllers now on the market. 
         [0070]    In operation, it is to be noted that the valve cylinder  108  only rotates clockwise and counterclockwise approximately 90 degrees within the valve housing  104  with the actual number of degrees of rotation set by the arc of slot  140 . 
         [0071]    Looking at  FIGS. 22 to 25  with respect to the valve&#39;s operation it is important to note that heat exchanger return port  156  and heat exchanger supply port  158  are fully open at all times by virtue of the width of the supply slot port  150  and return slot port  154  and the limited degrees of rotation of the valve cylinder  108  within the valve housing  104 . It is also important to note that the upper cylinder and lower cylinder move in unison and that all the corresponding return ports and supply ports reside in horizontal alignment with each other. 
         [0072]    For this valve&#39;s operational design to work, it is critical that the width of the cold and hot water return ports  160  and  166  as well as cold and hot water supply ports  164  and  162  do not exceed ⅓ of the number of degrees of rotation of the valve cylinder  108  within the valve housing  104  (Here that would be 30 degrees) and that they reside apart at least ⅓ of the number of degrees of rotation of the valve cylinder  108 . (Again here that would be 30 degrees.) 
         [0073]    On  FIGS. 10-12  showing the cylinder as interfacing with housing  FIG. 20 , it is also critical that the width of cylinder supply slot port  150  and cylinder return slot port  154  is at a minimum the 4/3 the number of degrees of rotation of the valve cylinder  108  in the valve housing  104 . (Here that would be 120 degrees) and that the heat exchanger supply port  158  reside more than the number of degrees of rotation of the valve cylinder  108  in the valve housing  104  away from either cold and hot water return ports  160  and  166 . Similarly, the heat exchanger supply port  158  must reside more than the number of degrees of rotation of the valve cylinder  108  in the valve housing  104  away from either the cold and hot water supply ports  164  and  162 . It is also critical that the width of supply slot port  150  and return slot port  154  is at a minimum the 4/3 the number of degrees of rotation of the valve cylinder  108  in the valve housing  104 . (Here that would be 120 degrees) and that the heat exchanger supply port  158  reside more than the number of degrees of rotation of the valve cylinder  108  in the valve housing  104  away from either cold and hot water supply ports  162  and  164 . Similarly, the heat exchanger return port  156  must reside more than the number of degrees of rotation of the valve cylinder  108  in the valve housing  104  away from either the cold and hot water return ports  160  and  166 . (Here that would be 90 degrees.) The supply crossover port  148  of the valve cylinder  108  is sized smaller in area than both the cold and hot water supply ports  164  and  162  of the valve housing  104 . Similarly, the return crossover port  152  of the valve cylinder  108  is smaller in area than the cold and hot water return ports  160  and  166  of the valve housing  104 . 
         [0074]    In this way the opening of the supply crossover port  148  in the valve cylinder  108  may be rotationally positioned between cold and hot water supply ports  164  and  162  of the valve housing  104  so as to close off the flow from either of the heat transfer media through the valve cylinder  108  and into the heat exchanger. This can best be seen in  FIGS. 33 and 34 . If a throttled flow is desired through the valve  102  the valve cylinder  108  is rotated to a position where the supply crossover port  148  does not totally align with either of the cold or hot water supply ports  164  and  162  of the valve housing  104 . When a full flow of either of the hot or cold water is desired, the supply port  158  is completely aligned with either of the cold or hot water supply ports  164  and  162  of the valve housing  104 . When changeover between the two different heat transfer medias is required the valve cylinder  108  must be rotated through a position wherein the supply crossover port  148  is sealed against the inner wall of the valve housing  104 . 
         [0000]                                          Nominal Valve Body &amp; Cylinder Dimensions For a ¼ Turn (90°) Valve*       (based on the upper chamber designated for return flow)                Angular           Dimensioned Item   Width**   Formulae               width of opening of supply   max 45°   max up to ½ the       ports 162 &amp; 164 and return       degrees of cylinder rotation       ports 160 &amp; 166 (valve       housing)       width of opening of supply   max 45°   max up to ½ the       crossover port 148 and       degrees of cylinder rotation       return crossover port 152       (valve cylinder)       space between adjacent   max 45°   max up to ½ the       supply ports 164 &amp; 162       degrees of cylinder rotation       and adjacent return ports       160 &amp; 166 (valve body)       width of opening of supply       Max up to 80 percent       slot port 150 or return slot       of cylinder diameter       port 154 (valve cylinder)       width of opening of heat   min 45°   min up to ½ the       exchanger supply port 158       number of degrees of       or heat exchanger return       rotation of the valve       port 156 (valve housing)       cylinder       space between heat   min 90°   min up to the number of       exchanger return port 156       degrees of rotation of       and adjacent return ports       the valve cylinder       160 &amp; 166 or       space between heat       exchanger supply port 158       and adjacent supply ports       164 &amp; 162 (valve housing)       space between return slot   min 90°   min up to the number of       port 154 and return       degrees of rotation of       crossover port 152 or       the valve cylinder       supply slot port 150 and       supply crossover port 148       (valve cylinder)               *Reference FIGS. 11, 12, 19-22.       **Taken from midpoint of the cylinder 108.            
The above dimensions are minimum and maximum design purposes only. In fabrication these must be adjusted and compensated for based on the building tolerances to ensure that there is a complete seal formed between these various ports as required so that there can be no unwanted bleed over or bypass flow between any of the valve body openings. This necessitates that the nominal angular dimensions of the valve body and valve cylinder of the previous chart are modified to ensure proper operation. The following chart details the dimensions for the preferred embodiment valve.
 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Valve Body &amp; Cylinder Dimensions For Preferred Embodiment(90°)Valve 
               
               
                 (based on the upper chamber designated for returnsupply flow) 
               
             
          
           
               
                   
                 Dimensioned Item 
                 Angular Width &amp; Tolerance 
               
               
                   
                   
               
               
                   
                 width of opening of return 
                 42° +/− 2° 
               
               
                   
                 ports 160 &amp; 166 and 
               
               
                   
                 supply ports 164 &amp; 162 
               
               
                   
                 (valve housing) 
               
               
                   
                 width of opening of return 
                 42° +/− 2° 
               
               
                   
                 crossover port 152 and 
               
               
                   
                 supply crossover port 148 
               
               
                   
                 (valve cylinder) 
               
               
                   
                 space between adjacent 
                 48° +/− 2° 
               
               
                   
                 return ports 160 &amp; 166 and 
               
               
                   
                 adjacent supply ports 164 
               
               
                   
                 &amp; 162 (valve body) 
               
               
                   
                 width of opening of return 
                 135° +/− 2°  
               
               
                   
                 slot port 154 or supply slot 
               
               
                   
                 port 150 (valve cylinder) 
               
               
                   
                 width of opening of heat 
                 42° +/− 2° 
               
               
                   
                 exchanger return port 156 
               
               
                   
                 or heat exchanger supply 
               
               
                   
                 port 158 (valve body) 
               
               
                   
                 space between heat 
                 92° +/− 2° 
               
               
                   
                 exchanger return port 156 
               
               
                   
                 and adjacent return ports 
               
               
                   
                 160 &amp; 166 or 
               
               
                   
                 space between heat 
               
               
                   
                 exchanger supply port 158 
               
               
                   
                 and adjacent supply ports 
               
               
                   
                 164 &amp; 162 (valve housing) 
               
               
                   
                 space between supply slot 
                 92° +/− 2° 
               
               
                   
                 port 150 and supply 
               
               
                   
                 crossover port 148 or 
               
               
                   
                 return slot port 154 and 
               
               
                   
                 return crossover port 152 
               
               
                   
                 (valve cylinder) 
               
               
                   
                   
               
             
          
         
       
     
         [0075]    Looking at FIGS.  1  and  22 - 25  the measurement controls of the valve  102  can best be seen. Thermocouple tap  182  and the rotor sensor taps  180  extend through passages through the valve housing  104 . The sensing ends of thermocouples for temperature monitoring are housed in the thermocouple tap  182  taps and relay temperature signals to instrumentation for valve control or indication. 
         [0076]    In assembly it is known that this valve will be a close tolerance valve and that the use of thrust washers or the like between the top of the valve cylinder  108  and the bottom face of the top plate  142  will serve to force the tapered valve cylinder  108  tightly against the tapered internal walls of the valve housing  104  and load the bearings so as to stabilize the internal structure of the unit and seal the respective valve cylinder chambers from leakage. 
         [0077]    There are numerous features and benefits to the aforementioned combined changeover and control valve such as: it replaces four valves in the conventional changeover configuration; it needs only one control output, instead of two or three; it leads to fewer components pipe and instrumentation to mount; water balancing valves are eliminated; It offers the speed in shut off like a ball valve with 45 degree isolation; it acts like a ball valve with the resultant low pressure drop making it ideal for straight line flow with minimal restrictions; it acts like a globe valve with a proportional response to position with larger valve ports, strainers are no longer needed to catch debris; larger valve ports and a simpler water path reduces water friction, and lowers pump energy; water temperature and flow sensing built into the valve itself; the valve is now truly pressure independent of supply pressure fluctuations; the valve can now be modulated to match Btu energy requirements; and the amount of heating Btu and cooling Btu consumption is now measurable at the air handler via computer. 
         [0078]    Although depicted with two separate chambers in the valve cylinder, it is known that three or more valve cylinder chambers may be utilized with the attendant inlet and outlet connections in an alternate embodiment of the present invention. Additionally, although depicted with the upper chamber designated for RETURN flow and the bottom chamber designated for SUPPLY flow, these can be reversed, as can the designations of any ports with reference to cold and hot. For this reason the designations used above herein may also be generically described as follows: 
         [0079]    Supply/Return crossover port=first crossover port; 
         [0080]    Supply/Return slotted port=first slotted port; 
         [0081]    Supply/Return crossover port=second crossover port; 
         [0082]    Supply/Return slotted port=second slotted port; 
         [0083]    First temperature fluid supply/return port=a first temperature fluid first port: 
         [0084]    Second temperature fluid supply/return port=a second temperature fluid second port; 
         [0085]    Heat exchanger valve supply/return port=a first heat exchanger valve port; 
         [0086]    First temperature fluid supply/return port=first temperature fluid second port; 
         [0087]    Second temperature fluid supply/return port=second temperature fluid second port; and 
         [0088]    Heat exchanger valve supply/return port=second heat exchanger valve. 
         [0089]    The above description will enable any person skilled in the art to make and use this invention. It also sets forth the best modes for carrying out this invention. There are numerous variations and modifications thereof that will also remain readily apparent to others skilled in the art, now that the general principles of the present invention have been disclosed. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. For example while this specification discloses a 90 degree rotation valve it is known that the valve cylinder must rotate within a limited number of degrees in the valve body, but that with modifications it need not be limited to a 90 degree rotation. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.