Abstract:
A near-boiler piping loop apparatus is provided including a primary/secondary piping loop interface apparatus having a unitary construction including a secondary loop shut-off valve, drain valve and drain port in each branch of a secondary loop for connection to a boiler. Supply branch piping and return branch piping connects the interface apparatus to the boiler and provides attachment points for auxiliary plumbing equipment. The apparatus is adapted to connect to pump in variable orientations using rotatable flanges on the interface apparatus and on a wye strainer in the secondary loop supply branch and includes a union fitting attached to the interface apparatus. The union fitting provides a mounting hole for a temperature or pressure gauge.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 12/836,248 which is a continuation-in-part (CIP) of U.S. patent application Ser. No. 12/753,408 filed on Apr. 2, 2010 which is a continuation-in-part (CIP) of U.S. patent application Ser. No. 12/615,547 filed on Nov. 10, 2009 which is a CIP of U.S. patent application Ser. No. 11/929,002 filed on Oct. 30, 2007 which is a CIP of U.S. patent application Ser. No. 11/648,376 filed on Dec. 29, 2006 which claims the benefit of U.S. Provisional Patent Application No. 60/756,007, filed on Jan. 4, 2006. The contents of U.S. patent application Ser. No. 12/753,408, U.S. patent application Ser. No. 12/615,547, U.S. patent application Ser. No. 11/929,002, U.S. patent application Ser. No. 11/648,376 and U.S. Provisional Patent Application No. 60/756,007 are incorporated herein by reference in their entirety. 
    
    
     FIELD OF INVENTION 
     The present invention relates to primary/secondary loop piping systems and more particularly to a near boiler piping apparatus. 
     BACKGROUND OF INVENTION 
     Primary/secondary (“P/S”) piping systems are used to isolate the pressure differential established by a pump from those established by other pumps in the same system. P/S piping allows any pump in the system to operate with virtually no tendency to induce flow, or even disturb flow, in other loops. P/S piping systems have become increasingly popular in many commercial and residential plumbing systems, such as hydronic heating and cooling systems. In such systems purge valves are essential to the operation and maintenance of the systems. Hydronic heating systems have gained popularity due to the comfortable average temperature they provide and uniformity in heating. Hydronic systems use water, or water-based solutions, to move thermal energy from where it is produced to where it is needed. Thermal energy is absorbed by the water at a heat source, conveyed by the water through the distribution piping, and finally released into a heated space by a heat emitter. Because hydronic heating and cooling systems rely on the flow of water through the pipes, the presence of air bubbles or pockets within the piping can lead to inefficiency and malfunction of the system. Purge valves are used to empty the system of air upon installation and during maintenance to provide for a more efficient system. Previous systems utilized purge valves located on the secondary loop in order to remove air from the secondary loop. The use of such valves can lead to pressure differentials that can affect the operation of the remainder of the system. 
     Hydronic systems utilize a liquid fluid to shift energy (i.e. BTUs) from one location to another. Typically this is accomplished by heating up (or in cooling applications, cooling) a liquid, such as water, or a mixture of water and other fluids (such as glycol antifreeze) to elevate the boiling point and lower the freezing point, and pumping the liquid to another location where the captured energy in the fluid is released. The hydronic solution can be heated through the use of a boiler, solar energy, geothermal pump, or any other means. The hydronic solution can be cooled by use of a heat pump, geothermal pump, or other such means of cooling the solution. 
     Hydronic systems require periodic maintenance, either to replace the water in the system or to replace a mixture of water and antifreeze, to perform de-scaling of the heat exchangers or to flush out sludge, etc. This is accomplished by draining the hydronic system, flushing with a de-scaling and/or cleaning solution, draining and filling the system back up with new fluid. Historically, purging a typical hydronic system has been accomplished by plumbing an assembly consisting of a boiler drain connected to a check valve and connected to another boiler drain. This method, while functional, is far from ideal. There are several connections as part of the assembly which each provide a potential leak path. Further, disadvantageously, the check valve typically does not provide for complete shutoff and during normal operation of the system the check valve offers some internal flow restriction. 
     SUMMARY OF INVENTION 
     A P/S loop adapter and valve apparatus that allows for the elimination of air from a piping system with no discernable pressure decrease is disclosed. The adapter allows for power purging off a secondary loop in the installation of hydronic systems. An embodiment of the present invention includes a valve body containing a flow channel extending through the body from a first primary loop port to a second primary loop port. The valve body also contains first and second secondary loop ports in communication with the flow channel. A flow diversion device is disposed in the valve body to control and alter the flow channel through the various ports of the valve body. The flow diversion device is disposed within the flow channel between the first and second secondary loop ports. The flow diversion device in a first position allows open flow through all ports of the valve. In a second position, the flow diversion device directs flow from the first primary loop port to the first secondary loop port and flow from the second secondary loop port to the second primary loop port. 
     Embodiments of the present invention provide improvements over historical systems and methods for purging hydronic systems by combining un-obstructive flow pattern of a ball valve and positive shutoff characteristics of a ball valve with fewer connection joints of the purge and fill valve assembly to alleviates the detriments such as internal flow restriction, incomplete shutoff and additional leak paths which are prevalent in the current systems and methods. 
     An illustrative embodiment of the present invention which is useful in purging hydronic systems provides a purge and fill valve which utilizes three ball valves that are combined into one valve assembly. The valve has a main ball and two valves that communicate from the main valve to an external connection (i.e., drain and fill connections). When the main ball is closed, and the two valves for external communication are opened, the hydronic system can be conveniently and completely emptied and filled from one location. New fluid can be introduced and push out the old fluid, all at one time. The system does not need to be fully emptied and then filled; a two stepped process, rather this is all done in one step. 
     It should be understood that labeling of “primary” flow path and “secondary” flow path is for illustration purposes and can be reversed without changing the scope of the present invention. For example, the primary flow path could be called the secondary flow path and vice versa. In a typical hydronic system, the primary loop is usually, but not always, associated with a boiler. The closely spaced tees hydraulically separates the primary flow path from the secondary flow path. That is, flow in the primary flow path does not affect flow in the secondary flow path and flow in the secondary flow path does not affect flow in the primary flow path. 
     In a further illustrative embodiment, where in comparison with the previous embodiment, the “primary” loop is now designated as “secondary,” a valve body contains a first primary loop port, a second primary loop port, a first secondary loop port and a second secondary loop port. The secondary loop ports are disposed at respective ends of a linear secondary loop portion of the valve body. A primary loop portion of the valve body is formed by a pair of closely spaced tees extending from the secondary loop portion. At least one main valve portion is disposed in at least one of the tees between the secondary loop portion and a primary loop port. A drain/venting valve portion extends from the main valve portion. A portion of the secondary loop portion between the tees is shared with the primary loop portion in which flow in a primary loop and a secondary loop are hydraulically separated. 
     People having ordinary skill in the art should appreciate that closely spaced tees are fluid flow path configurations in which two branches from a single flow path in a T shaped arrangement are spaced apart from each other such that center lines of each of the branches are less than about four times the diameter of the single flow path from which they stem. People having ordinary skill in the art should also appreciate that using closely spaced tees in a closed loop system creates a hydraulic separation where, due to lack of a pressure drop between the tees, a separate flow path is created or maintained through each of the tees. 
     Another illustrative embodiment of the invention provides a primary/secondary loop purge valve in which a valve body contains a first purge/fill port, a second purge/fill port, a first primary loop port and a second primary loop port. The primary loop ports are disposed at respective ends of a linear secondary loop portion of the valve body. A first purge/fill valve portion and a second purge/fill valve portion are formed in a pair of closely spaced tees extending from the primary loop portion. A main valve portion is disposed in the primary loop portion in alignment with one of the closely spaced tees. 
     Yet another illustrative embodiment of the invention provides a primary/secondary loop adapter having at least one main flow diversion device disposed in a respective at least one of a pair of closely spaced tees forming a primary loop portion of the adapter. A secondary loop portion of the adapter is formed by a linear adapter body from which the tees extend. The at least one flow diversion device may include a drain valve portion extending therefrom. One or more primary loop ports of the primary loop portion may include a flange adapted for connection to an apparatus, such as a pump, in the primary loop of a hydronic system. 
     Another embodiment of the invention provides a near-boiler piping loop apparatus including a primary/secondary piping loop interface apparatus having a unitary construction including a secondary loop shut-off valve, drain valve and drain port in each branch of a secondary loop for connection to a boiler. Supply branch piping and return branch piping connects the interface apparatus to the boiler and provides attachment points for auxiliary plumbing equipment. The apparatus is adapted to connect to pump in variable orientations using rotatable flanges on the interface apparatus and on a wye strainer in the secondary loop supply branch and includes a union fitting attached to the interface apparatus. The union fitting provides a mounting hole for a temperature or pressure gauge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features and advantages of the present invention will be more fully understood from the following detailed description of illustrative embodiments, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is an axial view of a first embodiment in accordance with the present invention; 
         FIG. 2  is a cut-away side view of the first embodiment in accordance with the present invention; 
         FIG. 3  is a top-down cut-away view of the first embodiment in accordance with the present invention; 
         FIG. 4  is a top-down cut-away view of a second embodiment having a flow diversion device disposed within the first and second secondary loop ports; 
         FIG. 5  is a top-down cut-away view of a third embodiment having multiple flow diversion devices disposed within the primary loop; 
         FIG. 6  is a plan view of a primary/secondary loop purge valve in normal operating position according to a fourth illustrative embodiment of the invention; 
         FIG. 7  is a section view of the primary/secondary loop purge valve in normal operating position according to the fourth illustrative embodiment of the invention; 
         FIG. 8  is a plan view of the primary/secondary loop purge valve in a purging position according to the fourth illustrative embodiment of the invention; 
         FIG. 9  is a section view of the primary/secondary loop purge valve in purging position according to the fourth illustrative embodiment of the invention; 
         FIG. 10  is a plan view of a primary/secondary loop purge valve in normal operating position according to a fifth illustrative embodiment of the invention; 
         FIG. 11  is a section view of the primary/secondary loop purge valve in normal operating position according to the fifth illustrative embodiment of the invention; 
         FIG. 12  is a plan view of the primary/secondary loop purge valve in a purging position according to the fifth illustrative embodiment of the invention; 
         FIG. 13  is a section view of the primary/secondary loop purge valve in purging position according to the fifth illustrative embodiment of the invention. 
         FIG. 14  is a plan view of a primary/secondary loop adapter in normal operating position according to a sixth illustrative embodiment of the invention; 
         FIG. 15  is a section view of the primary/secondary loop adapter in normal operating position according to the sixth illustrative embodiment of the invention; 
         FIG. 16  is a plan view of the primary/secondary loop adapter in a purging position according to the sixth illustrative embodiment of the invention; 
         FIG. 17  is a section view of the primary/secondary loop adapter in a first purging position according to the sixth illustrative embodiment of the invention; 
         FIG. 18  is a section view of the primary/secondary loop adapter in a second purging position according to the sixth illustrative embodiment of the invention; 
         FIG. 19  is a plan view of a primary/secondary loop adapter in normal operating position according to a seventh illustrative embodiment of the invention; 
         FIG. 20  is a plan view of a primary/secondary piping loop interface apparatus according to an eighth illustrative embodiment of the present invention; 
         FIG. 21  is a top cross sectional view of the primary/secondary loop interface apparatus according to the eighth embodiment of the present invention; 
         FIG. 22  is a schematic system diagram of a primary/secondary loop piping system including a primary/secondary loop interface apparatus according to an illustrative embodiment of the invention; 
         FIG. 23  is a plan view of a near boiler piping apparatus according to an illustrative embodiment of the invention; and 
         FIG. 24  is a process flow diagram showing a method for operating a primary/secondary loop interface apparatus to drain, fill or flush a secondary loop of a primary/secondary loop piping system according to an illustrative embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Detailed embodiments of the present invention are disclosed herein, however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific functional or structural details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed embodiment. 
     Turning to  FIG. 1 , an axial view of an embodiment in accordance with the present invention is shown. A valve body  1  defines a flow channel  16  that extends axially through the valve body  1  from a first primary loop port  18  to a second primary loop port. The valve body  1  also defines a first secondary loop port  12  and a second secondary loop port (not shown). An end cap  2  is affixed to the valve body  1  at the first primary loop port  18 . An actuator  20  extends from the valve body  1  enabling a first and second position of the valve. The actuator  20  includes a handle  11  affixed to the valve body by a handle nut  10 . A flow diversion device (not shown here) is connected to the handle  11 . The position of the actuator  20  in a first position configures the flow diversion device to allow flow axially through the entire flow channel  16  from the first primary loop port to the second primary loop flow port as well as through the first and second secondary loop flow ports. In a second position of the actuator  20 , the flow diversion device blocks the flow from the first primary loop port  18  to the second primary loop port. In this position, the first primary loop port  18  is in fluid communication with the first secondary loop port  12  only and the second primary loop port is in fluid communication with the second secondary loop port only. In a hydronic piping system, the valve in this position will break the primary loop and force all flow into the secondary loop. This position is used in such systems to purge the secondary loop of air during installation or maintenance. 
     Turning now to  FIG. 2  and  FIG. 3 , cut-away views of the first embodiment of the present invention are shown.  FIG. 2  depicts the embodiment from a side-view, while  FIG. 3  depicts the embodiment from a top-view. A valve body  1  defines a flow channel  16  axially though the valve from the first primary loop port  18  to the second primary loop port  22 . The first secondary loop port  12  and the second secondary loop port  14  are also in fluid communication with the flow channel  16 . The end cap  2  is disposed into the valve body  1  and mated with a seat retainer  3 . The actuator  20  extends from the valve body  1  containing a stem  6 , a stem seal  7  and a packing gland  8 . The actuator  20  also includes a handle  11  that is affixed to the stem  6  with the handle nut  10 . The actuator  20  repositions the flow diversion device  5  to alter the flow channels of the valve. The flow diversion device  5  is disposed within the valve body  1  in between the first secondary loop port  12  and the second secondary loop port  14 . The flow diversion device in this embodiment includes a ball defining two openings equal in diameter to the diameter of the flow channel  16 . The flow diversion device  5  is disposed between valve seats  4 . The position of the actuator  20  in a first position positions the flow diversion device to allow flow axially through the entire flow channel  16  from the first primary loop port to the second primary loop port as well as through the first and second secondary loop ports. In a second position of the actuator  20 , the flow diversion device blocks the flow from the first primary port  18  to the second primary port. In this position, the first primary loop port  18  is in fluid communication with the first secondary loop port  12  only and the second primary loop port is in fluid communication with the second secondary loop port only. 
     An alternative embodiment of the present invention is described with reference to  FIG. 4  which is similar to the embodiment shown in  FIG. 3  but also includes a flow diversion device disposed within each of the first and second secondary loop ports  12 ,  14 . A valve body  1  defines a flow channel  16  axially though the valve from the first primary loop port  18  to the second primary loop port  22 . The first secondary loop port  12  and the second secondary loop port  14  are also in fluid communication with the flow channel  16 . A first secondary flow diversion device  30  is disposed within the first secondary loop port and is configurable to a first position which closes the first secondary loop port and to a second position which opens the first secondary loop port. A second secondary flow diversion device  32  is disposed within the second secondary loop port and is configurable to a first position which closes the second secondary loop port and to a second position which opens the second secondary loop port. 
     In a still further alternative embodiment illustrated in  FIG. 5  the primary/secondary loop valve includes multiple valves in the primary loop to effect flow in the primary and secondary loops. The multiple flow diversion devices,  30 ,  32  are disposed in the primary flow channel  16  at the intersections of the primary and secondary flow paths. The flow diversion devices are configured, as described hereinbefore, to alternately provide flow through at least one of the primary and secondary loops. 
     The present invention also provides a method of purging a primary loop in a primary/secondary plumbing system using the inventive loop purge valve by connecting the first secondary loop port to a flushing fluid source and actuating the primary flow diversion device to configure the primary flow diversion device in its second position to close the flow path between the first primary loop port and second primary loop port. The first secondary flow diversion device is configured in the second position to allow the flushing fluid to flow into the first secondary loop port and the second secondary flow diversion device is configured in the second position to allow the flushing fluid to flow out from the second secondary loop port after flowing through the secondary loop (complete loop not shown). Upon completion of the purging procedure, each of the flow diversion devices can be configured to their respective first positions. 
     Although one illustrative embodiment described herein includes diversion devices in both of the secondary loop ports and in the primary loop path, one skilled in the art should appreciate that other configurations of diversion devices can be implemented, such as a diversion device in each of the first and second primary loop ports, or in other combinations, such as a diversion device at inputs and/or outputs of the loop ports (primary and/or secondary). 
       FIG. 6  is a plan view of a primary/secondary loop purge valve in normal operating position according to a fourth illustrative embodiment of the invention. The embodiment includes a valve body  60  containing a first primary loop port  62 , a second primary loop port  64 , a first secondary loop port  66  and a second secondary loop port  68 . The secondary loop ports  66 ,  68  are disposed at respective ends of a linear secondary loop portion  70  of the valve body  60 . A primary loop portion  72  of the valve body  60  is formed by a pair of “closely” spaced tees  74 ,  76  extending from the secondary loop portion  70 . At least one main valve portion  78  is disposed in at least one of the tees  76  between the secondary loop portion  70  and a primary loop port  64 . A drain/venting valve portion  80  extends from the main valve portion  78 . An end cap  81  is affixed to the valve body  60  at a drain port  83  of the drain/venting valve portion  80 . A portion of the secondary loop portion  70  between the tees  74 ,  76  is shared with the primary loop portion in which flow in a primary loop and a secondary loop are “hydraulically separated.” 
     A main actuator  85  extends from the valve body  60  enabling a first and second position of the main valve portion  78 . A main flow diversion device (not shown here) is connected to a main handle  87  via the main actuator  85 . The main handle  87  is retained to the main actuator with a nut  89 . A purge valve handle  91  is connected to a purge valve flow diversion device (not shown here) via a purge valve actuator (not shown here). The purge valve handle  91  is retained to the purge valve actuator by a screw  93 . 
       FIG. 7  is a sectioned view of the primary/secondary loop purge valve in normal operating position according to the fourth illustrative embodiment of the invention. A primary loop fluid flow path  82  is shown by arrows extending into tee  74 , through the secondary loop portion  70  and into tee  76 . Fluid can flow in either direction along the primary loop fluid flow path  82 . A secondary loop flow path  84  is shown by arrows extending into the first secondary loop port  66  through the secondary loop portion  70  and out from the second secondary loop port  68 . It should be understood that a common flow of both the primary loop flow path  82  and the secondary loop flow path  84  exists in the secondary loop portion  70 . 
     The main valve portion  78  is shown in the normal operation position in which fluid in the primary fluid flow path  82  can flow from secondary loop portion  70  through the main valve portion  78  to the primary loop port  64 . The main flow diversion device  79  in the main valve portion  78  is shown in a first position to enable flow in the primary flow path between tee  76  and the second primary loop port  64  while preventing flow to the drain/venting valve portion  80 . In this illustrative embodiment, the main flow diversion device  79  is a first ball having a through hole  95  extending through its center and a blind hole  97  extending orthogonal to the through hole to its center. The first ball is rotatable on an axis of the main actuator  85  ( FIG. 7 ) by movement of handle  87  (best seen in  FIG. 6 ) and main actuator  85  ( FIG. 7 ). The first ball forms a seal with sealing portions  99  and  101 . 
     The purge valve flow diversion device  103  in the drain/venting valve portion  80  is shown in its normally closed position in which fluid in the primary flow path  82  is prevented from flowing between the main valve portion  78  and the drain port  83 . In this illustrative embodiment, the purge valve flow diversion device  103  is a second ball having a through hole extending through its center. The second ball is rotatable on an axis of the purge valve actuator (not shown) which extends through its center and normal to the plane of drawing in  FIG. 7  by movement of purge valve handle  91  (best seen in  FIG. 6 ) and the purge valve actuator retained thereto (not shown) by screw  93 . The second ball forms a seal with sealing portions  105  and  107 . 
       FIG. 8  is a plan view of the primary/secondary loop purge valve in a purge/drain position according to the fourth illustrative embodiment of the invention. The main valve handle  87  and main actuator  85  are rotated 90 degrees counter clockwise relative to their normal operating position. The purge valve handle  91  is rotated 90 degrees clockwise relative to its normally closed position. 
       FIG. 9  is a section view of the primary/secondary loop purge valve in a purge/drain position according to the fourth illustrative embodiment of the invention. The primary loop fluid flow path  82  is shown by arrows extending into tee  74 , through the secondary loop portion  70  and into tee  76 . Fluid in the primary flow path flows into main valve portion  78  where it is diverted by the main flow diversion device  79  into the drain/venting valve portion  80 . Because the purge valve handle is in the purge/drain position, fluid entering the drain/venting valve portion  80  can flow through the purge valve flow diversion device  103  to the drain port  83 . Protective cap  81  can be removed to vent or drain the system via the primary flow path  82 . 
     Again, it should be understood that labeling of “primary” flow path and “secondary” flow path is for illustration purposes and can be reversed without changing the scope of the present invention. For example, the primary flow path could be called the secondary flow path and vice versa. In a typical hydronic system, the primary loop is usually, but not always, associated with a boiler. The closely spaced tees hydraulically separates the primary flow path from the secondary flow path. That is, flow in the primary flow path does not affect flow in the secondary flow path and flow in the secondary flow path does not affect flow in the primary flow path. 
     In normal operating position of valve body  60 , the affect of closely spaced tees  74 , 76  and main valve portion  78  in the normal operating position is to hydraulically separate the primary flow path  82  from the secondary flow path  84 . 
     In a second configuration, the main valve portion  78  closes off the primary flow path  82  and the drain/venting valve portion  80  is opened. The flow from the primary flow path  82  goes into a flow passageway, secondary loop portion  70 , that is shared with the secondary flow path  84 , then back to the primary flow path  82 . Because the main valve portion is “closed”, i.e. in its second configuration, and the drain/venting valve portion  80  is open, for example any trapped air is purged out of the system. Once the trapped air has been purged out of the system, the main valve portion  78  and the drain/venting valve portion  80  are returned to their normal operating positions. 
     Hydronic systems that use the primary/secondary piping method typically have circulation pumps installed in each loop. The circulation pump forces the fluid through the loop until the fluid encounters an obstacle, such as a shut valve. By providing a new path for the fluid to flow (e.g., out of the drain/venting valve portion  80 ) the fluid can continue to flow. Upon commissioning a piping system, or performing maintenance on a system, air is tapped inside the piping system. By power pumping when the main valve portion  78  and drain venting valve portion  80  are in the drain/purge configuration, air is power purged from the system via the drain port  83 . 
     It should be appreciated that the flow directions in the primary flow path  82  and the secondary flow path  84  can be reversed within the scope of the present invention. In such cases, the main flow diversion device  79  is oriented 180 degrees relative to the orientation shown so that the closed portion is located downstream, i.e. toward the lower portion of main valve portion  79  when the primary flow path is oriented from the second primary loop port  64  toward tee  76 . 
       FIG. 10  is a plan view of a primary/secondary loop purge valve in normal operating position according to a fifth illustrative embodiment of the invention. The embodiment includes a valve body  100  containing a first purge/fill port  102 , a second purge/fill port  104 , a first primary loop port  106  and a second primary loop port  108 . The primary loop ports  106 ,  108  are disposed at respective ends of a linear primary loop portion  110  of the valve body  100 . A first purge/fill valve portion  112  and a second purge/fill valve portion  114  are formed in a pair of closely spaced tees  116 ,  118  extending from the primary loop portion  110 . Persons having ordinary skill in the art should appreciate that the closely spaced tees  116 ,  118  provide hydraulic separation in the primary loop portion  110  between the first purge/fill valve portion  112  and the second purge/fill valve portion  114 . A main valve portion  120  is disposed in the primary loop portion  110  in alignment with one of the closely spaced tees  116 . 
     A main actuator  122  extends from the valve body  100  enabling a first and second position of the main valve portion  120 . A main flow diversion device (not shown here) is connected to a main handle  124  via the main actuator  122 . The main handle  124  is retained to the main actuator with a nut  126 . A first purge/fill valve handle  128  is connected to a first purge/fill valve flow diversion device (not shown here) via a first purge/fill valve actuator (not shown here). The first purge/fill valve handle  128  is retained to the purge/fill valve actuator by a screw  130 . A second purge/fill valve handle  132  is connected to a second purge/fill valve flow diversion device (not shown here) via a second purge/fill valve actuator (not shown here). The second purge/fill valve handle  132  is retained to the second purge/fill valve actuator by a screw  134 . 
       FIG. 11  is a section view of the primary/secondary loop purge valve in normal operating position according to the fifth illustrative embodiment of the invention. A primary loop fluid flow path  136  is shown by arrows extending through the primary loop portion  110 . In the configuration shown in  FIG. 11 , fluid can flow in either direction along the primary loop fluid flow path  136 . 
     The main valve portion  120  is shown in the normal operation position in which fluid in the primary fluid flow path  136  can flow between the first primary loop port  106  and the second primary loop port  108  via the main valve portion  120 . The main flow diversion device  138  in the main valve portion  120  is shown in a first position to enable flow in the primary flow path. The first purge/drain flow diversion device  140  and second purge/drain flow diversion device  142  are shown in a first position to prevent flow from the primary flow path to either the first purge/drain port  102  or the second purge/drain port  104 . In this illustrative embodiment, the main flow diversion device  138  is a first ball having a through hole  144  extending through its center and a blind hole  146  extending orthogonal to the through hole to its center. The first ball is rotatable on an axis of the main actuator  122  ( FIG. 10 ) by movement of handle  124  and main actuator  122  ( FIG. 10 ). The first ball forms a seal with sealing portions  148  and  150 . 
     The first purge/fill valve flow diversion device  140  in the first purge/fill valve portion  112  is shown in its normally closed position in which fluid in the primary flow path  136  is prevented from flowing between the main valve portion  120  and the first purge/fill port  102 . In this illustrative embodiment, the first purge/fill valve flow diversion device  140  is a second ball having a through hole extending through its center. The second ball is rotatable on an axis of the first purge/fill valve actuator (not shown) which extends through its center and normal to the plane of drawing in  FIG. 11  by movement of first purge/fill valve handle  128  ( FIG. 10 ) and the first purge valve actuator retained thereto (not shown) by screw  130  ( FIG. 10 ). The second ball forms a seal with sealing portions  151  and  152 . 
     The second purge/fill valve flow diversion device  142  in the second purge/fill valve portion  114  is shown in its normally closed position in which fluid in the primary flow path  136  is prevented from flowing between the primary loop portion  110  and the second purge/fill port  104 . In this illustrative embodiment, the second purge/fill valve flow diversion device  142  is a third ball having a through hole extending through its center. The third ball is rotatable on an axis of the second purge/fill valve actuator (not shown) which extends through its center and normal to the plane of drawing in  FIG. 11  by movement of second purge/fill valve handle  132  ( FIG. 10 ) and the first purge valve actuator retained thereto (not shown) by screw  134  ( FIG. 10 ). The second ball forms a seal with sealing portions  154  and  156 . 
       FIG. 12  is a plan view of the primary/secondary loop purge valve in a purging position according to the fifth illustrative embodiment of the invention. The main valve handle  124  and main actuator  122  are rotated 90 degrees counter clockwise relative to their normal operating position. The first purge/fill valve handle  128  is rotated 90 degrees clockwise relative to its normally closed position and is obscured in this view by the main valve handle  124 . The second purge/fill valve handle  132  is rotated 90 degrees counter-clockwise relative to its normally closed position. 
       FIG. 13  is a section view of the primary/secondary loop purge valve in purging position according to the fifth illustrative embodiment of the invention. A first purge/fill loop flow path  160  is shown by arrows extending between primary loop port  106  and tee  116 . Fluid in the first purge/fill loop flow path  160  can flow through main valve portion  120  where it is diverted by the main flow diversion device  138  into the first purge/fill valve portion  112 . Because the first purge/fill valve handle  128  (best seen in  FIG. 10 ) is in the purge/fill position, fluid entering the first purge/fill valve portion  112  can flow through the first purge/fill flow diversion device  140  to the first purge/fill port  102 . 
     A second purge/fill loop flow path  162  is shown by arrows extending between primary loop port  108  and tee  118 . Fluid in the second purge/fill loop flow path  162  can not flow through main valve portion  120  because it is diverted by the main flow diversion device  138 . Because the second purge/fill valve handle  132  (best seen in  FIG. 12 ) is in the purge/fill position, fluid entering the second purge/fill valve portion  114  from primary loop port  108  can flow through the second purge/fill flow diversion device  142  to the second purge/fill port  104 . 
       FIG. 14  is a plan view of a primary/secondary loop adapter in normal operating position according to a sixth illustrative embodiment of the invention. The embodiment includes a valve body  260  containing a first primary loop port  262 , a second primary loop port  264 , a first secondary loop port  266  and a second secondary loop port  268 . The secondary loop ports  266 ,  268  are disposed at respective ends of a linear secondary loop portion  270  of the valve body  260 . A primary loop portion  272  of the valve body  260  is formed by a pair of “closely” spaced tees  274 ,  276  extending from the secondary loop portion  270 . A first main valve portion  278  is disposed in a first one of the tees  276  between the secondary loop portion  270  and a primary loop port  264 . A second main valve portion  300  is disposed in a second one of the tees  274  between the secondary loop portion  270  and primary loop port  262 . In this illustrative embodiment, the primary loop port  262  includes a flange  302  which may be adapted for connecting directly to an apparatus in the primary loop, such as a pump, for example. The flange  302  may be implemented as a multi-piece rotatable flange such as disclosed in co-pending, commonly owned U.S. patent application Ser. No. 12/749,020 entitled, Rotatable Flange Apparatus and Method which is hereby incorporated by reference in its entirety. 
     A drain/venting valve portion  280  may extend from one or both main valve portions  278 ,  300 . In the embodiment shown in  FIG. 14  only one main valve portion  278  has a drain/venting valve portion  280  extending therefrom. Drain/venting valve portion  280  extends from the main valve portion  278 . An end cap (not shown) may be affixed to the valve body  260  at a drain port  283  of the drain/venting valve portion  280 . It should be understood that a similar drain/venting valve portion with or without an end cap could also extend from main valve portion  300  within the scope of the present disclosure. 
     A portion of the secondary loop portion  270  between the tees  274 ,  276  is shared with the primary loop portion in which flow in a primary loop and a secondary loop are “hydraulically separated.” 
     A main actuator  285  extends from the valve body  260  enabling a first and second position of the main valve portion  278 . A main flow diversion device (not shown here) is connected to a main handle  287  via the main actuator  285 . The main handle  287  is retained to the main actuator with a nut  289 . A purge valve handle  291  is connected to a purge valve flow diversion device (not shown here) via a purge valve actuator (not shown here). The purge valve handle  291  is retained to the purge valve actuator by a screw  293 . 
       FIG. 15  is a sectioned view of the primary/secondary loop adapter in normal operating position according to a sixth illustrative embodiment of the invention. A primary loop fluid flow path  282  is shown by arrows extending into tee  274 , through the secondary loop portion  270  and into tee  276 . Fluid can flow in either direction along the primary loop fluid flow path  282 . A secondary loop flow path  284  is shown by arrows extending into the first secondary loop port  266  through the secondary loop portion  270  and out from the second secondary loop port  268 . It should be understood that a common flow of both the primary loop flow path  282  and the secondary loop flow path  284  exists in the secondary loop portion  270 . 
     The first main valve portion  278  is shown in the normal operation position in which fluid in the primary fluid flow path  282  can flow from secondary loop portion  270  through the first main valve portion  278  to the primary loop port  264 . The second main valve portion  300  is also shown in the normal operation position in which fluid in the primary fluid flow path  282  can flow from secondary loop portion  270  through the second main valve portion  300  to the primary loop port  262 . 
     The main flow diversion devices  279 ,  279 ′ in the main valve portion  278 ,  300  are shown in a first position to enable flow in the primary flow path between tees  274 ,  276  and the primary loop ports  262 ,  264  while preventing flow to the drain/venting valve portion  280 . In this illustrative embodiment, the main flow diversion devices  279 ,  279 ′ are balls having a through hole  295 ,  295 ′ extending through their center. In embodiments in which a drain/venting valve portion  280  is extended from a main valve portion as shown extending from the first main valve portion  278 , the ball includes a blind hole  297 , extending orthogonal to the through hole to its center. The ball is rotatable on an axis of the main actuator  285 , by movement of handles  287 ,  287 ′ and main actuators  285 ,  285 ′ (best seen in  FIG. 14 ). The ball forms a seal with sealing portions  299  and  301 . 
     The purge valve flow diversion device  303  in the drain/venting valve portion  280  is shown in its normally closed position in which fluid in the primary flow path  282  is prevented from flowing between the main valve portion  278  and the drain port  283 . In this illustrative embodiment, the purge valve flow diversion device  303  is a second ball having a through hole extending through its center. The second ball is rotatable, on an axis of the purge valve actuator (not shown) which extends substantially through its center and normal to the plane of drawing in  FIG. 15 , by movement of purge valve handle  291  and the purge valve actuator retained thereto by a screw  293  (best seen in  FIG. 14 ). The second ball forms a seal with sealing portions  305  and  307 . 
       FIG. 16  is a plan view of the primary/secondary loop adapter in a purge/drain position according to the sixth illustrative embodiment of the invention. The main valve handles  287 ,  287 ′ and main actuators  285  (second main actuator not shown) are rotated 90 degrees counter clockwise relative to their normal operating position. The purge valve handle  291  is rotated 90 degrees clockwise relative to its normally closed position. It should be appreciated that the actuators could be configured for rotation in the opposite directions. 
       FIG. 17  is a sectioned view of the primary/secondary loop adapter in a first purge/drain position according to the sixth illustrative embodiment of the invention. The primary loop fluid flow path  282  is shown by arrows extending into tee  274 , through the secondary loop portion  270  and into tee  276 . Fluid in the primary flow path flows into first main valve portion  278  where it is diverted by the first main flow diversion device  279  into the drain/venting valve portion  280 . Because the purge valve handle is in the first purge/drain position, fluid entering the drain/venting valve portion  280  from tee  276  can flow through the purge valve flow diversion device  303  to the drain port  283 . A protective cap (not shown) can be removed to vent or drain the system via the primary flow path  282 . Fluid in the primary flow path  282  that is directed into the second main valve portion  300  is blocked by the second main flow diversion device  279 ′. 
       FIG. 18  is a sectioned view of the primary/secondary loop adapter in a second purge/drain position according to the sixth illustrative embodiment of the invention. The primary loop fluid flow path  282  is shown by arrows extending through the primary loop port  264  into the first main valve portion  278 . Fluid in the primary flow path flows into first main valve portion  278  where it is diverted by the first main flow diversion device  279  into the drain/venting valve portion  280 . Because the purge valve handle is in the second purge/drain position, fluid entering the drain/venting valve portion  280  from primary loop port  264  can flow through the purge valve flow diversion device  303  to the drain port  283 . Fluid in the secondary flow path  284  that is directed into the second main valve portion  300  is blocked by the second main flow diversion device  279 ′. Fluid in the secondary flow path  284  that is directed into the first main valve portion  278  is blocked by the first main flow diversion device  279 . 
     Persons having ordinary skill in the art should appreciate, with reference to  FIGS. 15-18 , that the second main flow diversion device  279 ′ can be rotated to any one of three separate flow positions by rotation of the actuator  285  through about 180 degrees. That is, in the illustrative embodiment, the main flow diversion device operates as a 3-way valve. In the various illustrative embodiments of the invention, either or both of the main flow diversion devices  279 ,  279 ′ can be so configured to operate as three way valves. 
       FIG. 19  is a plan view of a primary/secondary loop adapter  400  in normal operating position according to a seventh illustrative embodiment of the invention. The embodiment includes a valve body  360  containing a first primary loop port  362 , a second primary loop port  364 , a first secondary loop port  366  and a second secondary loop port  268 . The secondary loop ports  366 ,  368  are disposed at respective ends of a linear secondary loop portion  370  of the valve body  360 . A primary loop portion  372  of the valve body  360  is formed by a pair of “closely” spaced tees  374 ,  376  extending from the secondary loop portion  370 . A main valve portion  402  is disposed in a first one of the tees  374  between the secondary loop portion  370  and a primary loop port  362 . In this illustrative embodiment, the primary loop port  362  includes a flange  404  which may be adapted for connecting directly to an apparatus in the primary loop, such as a pump, for example. 
       FIG. 20  is a plan view of an eighth illustrative embodiment of the primary/secondary loop interface apparatus. The primary-secondary piping loop interface apparatus  500  includes a primary loop portion  502  including a tubular fluid conduit having a circumferential sidewall, a first end  504  and a second end  506  for interfacing with a primary loop in a plumbing system. A secondary loop portion  508  includes a first neck portion  510  and a second neck portion  512  extending from the circumferential sidewall. The first neck portion  510  and second neck portion  512  are substantially parallel to each other and substantially perpendicular to the primary loop portion  502  to form a pair of closely spaced tees suitable for hydraulic separation of fluid flow between the primary loop portion  502  and the secondary loop portion  508 . 
     The secondary loop portion  508  further includes at least one drain valve portion  514 ,  514 ′ extending from a corresponding neck portion  510 ,  512 . The drain valve portion(s)  514 ,  514 ′ include a respective drain shut-off valve  516 ,  516 ′ disposed therein and a respective drain port  518 ,  518 ′. The respective drain shut-off valve(s)  516 ,  516 ′ are arranged to enable or disable flow through the respective drain port(s)  518 ,  518 ′. 
     The secondary loop portion  508  also includes at least one secondary loop interface port  520 ,  520 ′ terminating each respective neck portion  510 ,  512  and at least one secondary loop shut-off valve  522 ,  522 ′ disposed in the corresponding neck portion  510 ,  512  between the respective secondary loop interface port  518 ,  518 ′ and the circumferential sidewall of the primary loop portion  502 . 
     In the eighth illustrative embodiment, the secondary loop shut-off valves  522 ,  522 ′ includes an open operative position configured to open a main flow-path between the respective secondary loop interface port  520 ,  520 ′ and the primary loop portion  502 , and a closed operative position configured to close the main flow path between the respective secondary loop interface port  520 ,  520 ′ and the primary loop portion  502 . A drain flow path between the secondary loop interface port  520 ,  520 ′ of the respective neck portion  510 ,  512  and the respective drain valve portion  514 ,  514 ′ is configured to be open in both the open operative position and the closed operative position of the secondary loop shut-off valves  522 ,  522 ′. 
     In the illustrative embodiment, a rotatable flange  523  such as described in commonly owned co-pending U.S. patent application Ser. No. 12/749,020, which is incorporated herein by reference in its entirety, is configured to secure at least one of the secondary loop interface ports  520 ,  520 ′ to an arbitrarily rotated flange interface in the secondary loop of a primary/secondary loop plumbing system. 
       FIG. 21  shows a top cross sectional view of the eighth illustrative embodiment wherein the section is taken through the secondary loop shut-off valves  522 ,  522 ′ and the drain shut-off valves  516 ,  516 ′. The secondary loop shut-off valves  522 ,  522 ′ each include a flow diversion device  524 ,  524 ′ disposed in a junction between a respective neck portion  510 ,  512  and corresponding drain valve portion  514 ,  514 ′. 
     Each of the flow diversion devices  524 ,  524 ′ include a main ball portion  526 ,  526 ′ having a through hole  528 ,  528 ′ extending centrally there-through and having a blind hole  530 ,  530 ′ extending orthogonally to the through hole  528 ,  528 ′ from the center of the respective main ball portion  526 ,  526 ′. The main ball portion  526 ,  526 ′ is rotatable about a main ball axis  532 ,  532 ′ through the center of the respective main ball portion  526 ,  526 ′ and orthogonal to a plane of the respective through hole  528 ,  528 ′ and blind hole  530 ,  530 ′. In the open operative position of a respective secondary loop shut-off valve  522 ,  522 ′, the respective through hole  528 ,  528 ′ is aligned with the corresponding secondary loop interface port  520 ,  520 ′ ( FIG. 20 ) and wherein in the closed operative position, the respective blind hole  530 ,  530 ′ is aligned with the corresponding secondary loop interface port  520 ,  520 ′ ( FIG. 20 ). 
     Each of the drain shut-off valves  516 ,  516 ′ includes a drain ball portion  534 ,  534 ′ having a through hole  536 ,  536 ′ extending centrally there-through and is rotatable through an arc of about 90 degrees about a drain ball axis  538 ,  538 ′. Each of the drain ball axes  538 ,  538 ′ are perpendicular to the through hole  536 ,  536 ′ of the drain ball portion and parallel to the corresponding main ball axis  532 ,  532 ′. 
     In the illustrative embodiment, a first drain valve portion  514  is parallel to the primary loop portion  502  and directed away from the second neck portion  512 , and the second drain valve portion  514 ′ is directed generally toward the first neck portion  510  and oriented at an angle  540  of about 45 degrees relative to the primary loop portion  502  in this illustrative embodiment. An angle of 0 to 90 degrees or preferably 15-75 degrees may be implemented to provide clearance around the first neck portion  510  for access to the drain valve port  518 ′ of the second drain valve portion  514 ′. 
     An implementation of the primary/secondary loop interface apparatus according to the eighth embodiment of the invention in a primary/secondary loop piping system is described with reference to  FIG. 22 . The primary-secondary loop piping system includes at least one boiler  602  in fluid communication with a primary piping loop  604 . At least one primary loop pump  606  is installed in the primary piping loop  604 . At least one secondary piping loop  608 ,  608 ′,  608 ″ branches away from the primary loop  604  and returns downstream to the primary loop  608  via a pair of closely spaced tees in a primary-secondary piping loop interface apparatus  500 . 
     In the primary/secondary loop piping system shown in  FIG. 22 , each of the primary-secondary piping loop interfaces  500  are substantially identical to those described hereinbefore with reference to  FIGS. 20 and 21 . 
     At least one secondary loop pump  610  is installed in each of the secondary piping loops  608 . In each secondary loop  608 , the secondary loop pump  610  is mounted to a flange  523  on one of the secondary loop interface ports ( 520 ′  FIG. 20 ). In the illustrative embodiment the flange  523  is a rotatable flange as described in the referenced U.S. patent application Ser. No. 12/749,020. However, it should be understood that various alternative embodiments could be configured wherein flange  523  is a fixed flange within the scope of the present disclosure. The rotatable flange  523  is configurable to secure a secondary loop interface port ( 520 ′  FIG. 20 ) to an arbitrarily rotated flange interface in the secondary loop  608 , such as a mating flange on the secondary loop pump  610 . The rotatable flange allows the secondary loop pump  610  or other component having a flange interface to be connected to the primary/secondary loop interface apparatus  500  over a range of relative angular displacements between the secondary loop pump  610  and the primary/secondary loop interface apparatus  500 . This is beneficial where mounting a pump in a particular fixed angular displacement could be difficult or impossible due to space constraints, for example, or other zone loop. 
     In the illustrative embodiment, the primary/secondary piping loop system includes a plurality of secondary piping loops  608  wherein one or more of the secondary piping loops  608  each constitute a separate heating zone, for example. Another of secondary piping loops  608  could constitute a snow melt system, for example. 
     In the illustrative embodiment the boiler  602  is also installed in a secondary loop referred to herein as a near boiler piping loop  612 . A secondary loop pump  614  in the near boiler piping loop  612  can be installed to the primary-secondary piping loop interfaces  500  in the same manner as described with regard to the secondary loop pumps  610  in secondary loops  608 . Alternative embodiments of a near boiler piping loop  612  may include a secondary loop pump which is incorporated internally within the boiler rather than external to the boiler  602  as shown in  FIG. 22 . In these alternative embodiments, the flange  523  on the primary-secondary piping loop interfaces  500  may be replaced by a union fitting for connecting to piping in the near boiler piping loop  612 . 
     Illustratively, the primary loop pump  606  is installed in the primary loop  604  between the near boiler piping loop  612  and the other secondary loops  608  wherein energy from the boiler is distributed. It should be understood that alternative embodiments within the scope of the present disclosure could include a boiler installed in the primary loop, rather than in a secondary loop as shown in  FIG. 22 . Such embodiments may include a pump incorporated internally with the boiler rather than a separately installed primary loop  606  as shown in  FIG. 22 . 
     In another implementation, the primary-secondary piping loop interface apparatus  500  according to the eighth embodiment of the invention is included in a near boiler piping apparatus which is described with reference to  FIG. 23 . The near boiler piping apparatus  700 , includes a primary-secondary loop interface apparatus  500  which was described hereinbefore with reference to  FIGS. 20 and 21  and a return branch pipe section  702  attached to the second secondary loop interface port ( 520   FIG. 20 ) of the primary-secondary loop interface apparatus  500 . 
     In the illustrative embodiment, a first flange  523  is configured on the first secondary loop interface port ( 520 ′  FIG. 20 ) to allow attachment of a first flange interface of a circulation pump  704  to the first secondary loop interface port ( 520 ′  FIG. 20 ). In the illustrative embodiment the first flange  523  is a rotatable flange configured on the first secondary loop interface port ( 520 ′  FIG. 20 ) to allow attachment of an arbitrarily rotated first flange interface of the circulation pump  704  to the first secondary loop interface port ( 520 ′  FIG. 20 ). 
     The return branch pipe section  702  includes a return branch boiler attachment tee  706 . The return branch boiler attachment tee  706  includes a return branch boiler attachment fitting  708  and a return branch auxiliary attachment point  710 . 
     A second flange  712  is configured on wye strainer  714  which is attached to a supply branch pipe section  716  for mounting the wye strainer  714  to a second flange interface of the circulation pump  704 . In the illustrative embodiment, the second flange  712  is a rotatable flange configured on the wye strainer  714  to allow attachment of an arbitrarily rotated second flange interface of the circulation pump  704 . A wye strainer  714  with a rotatable flange which is suitable for use in the near boiler piping apparatus  700  is described in Applicant&#39;s co-pending U.S. patent application entitled ROTATABLE FLANGE WYE STRAINER, attorney docket no. 55807.16-CIP, which is a Continuation-in-Part of U.S. patent application Ser. No. 12/749,020, filed on Mar. 29, 2010 which are incorporated herein by reference in their entirety. 
     The supply branch pipe section  716  includes a supply branch boiler attachment tee  718 . In the illustrative embodiment, the supply branch boiler attachment tee  718  includes a supply branch boiler attachment fitting  720  and a supply branch auxiliary attachment point  722 . The supply branch auxiliary attachment point  722  and return branch auxiliary attachment point  710  can be used for attaching an indirect water heater to the boiler, for example. 
     A union fitting  724  connects the return branch pipe section  702  to the second secondary loop interface port ( 520 ,  FIG. 20 ). In the illustrative embodiment, the union fitting  724  includes a gauge hole configured for connecting a gauge  726  such as a pressure gauge or temperature gauge, for example, to the union fitting  724 . 
     In the illustrative embodiment, the return branch pipe section includes a knee portion  728  configured to offset the return branch boiler attachment tee  706  from the supply branch boiler attachment tee  718 . 
     Illustrative embodiments of the present invention also provide a method of servicing a secondary loop in a primary-secondary loop piping system by operating the primary-secondary piping loop interface apparatus described hereinbefore with reference to  FIGS. 20 and 21 . In an embodiment described with reference to  FIG. 24 , the method  800  of operating the primary-secondary piping loop interface apparatus includes the step of setting each of the at least one secondary loop shut-off valves ( 522 ,  522 ′,  FIG. 20 ) to their respective closed operative position  802 . 
     In the illustrative embodiment, a draining operation of the primary-secondary loop interface apparatus requires the stop of draining a corresponding secondary loop of the primary-secondary loop piping system by opening the respective drain shut-off valves at least one of the drain valve portions. 
     In the illustrative embodiment, a filling operation of the primary-secondary loop piping interface includes the steps of filling a corresponding secondary loop of the primary-secondary loop piping system by connecting a fill hose to at least one of the drain ports of at least one of the drain valve portions  806  and opening the respective drain shut-off valve of the drain valve portion  808 . 
     In the illustrative embodiment, a flushing operation of the primary-secondary loop piping interface includes the steps of flushing a corresponding secondary loop of the primary-secondary loop piping system by connecting a fill hose to at least one of the drain ports of at least one of the drain valve portions  810 , opening the respective drain shut-off valve of the respective drain valve portion  812  and opening the drain shut-off valve in another of the at least one drain valve portions  814 . 
     It should be appreciated that a “diversion device” can be one or more devices for diverting flow in a desired manner. The descriptions of flow paths and flow directions herein which identify flow paths or other elements with labels such as primary and secondary, or first and second are for illustrative purposes to provide labels for a particular embodiment, drawing or claim and are not indicative of a hierarchal relationship between the elements. Further it should be understood that such labels may be reversed in any of the embodiments described or claimed herein without affecting the scope of the present disclosure. Similarly, it should be understood that the clockwise or counterclockwise direction of rotations of certain elements such as flow diversion devices and handles described herein are for illustrative purposes only and may generally be reversed without changing the scope of the present disclosure. 
     While the invention has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions and/or additions may be made and substantial equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated any use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.