Abstract:
A manifold for a heat exchanging appliance is disclosed. The manifold may include an externally adjustable bypass valve, a compression fitting for connecting a conduit to the manifold, a flow cup for adding passes to the heat exchanging appliance, an apparatus for conveying the temperature of a medium in a nonconductive manifold to a temperature sensor, a blind threaded hole for engaging an insertion apparatus to the manifold, and an integrated thermostatic valve assembly. Methods for controlling the pressure in a pressure chamber, for connecting a conduit to a manifold, for adding passes to the heat exchanging appliance, for conveying the temperature of the medium to a temperature sensor, for engaging an insertion apparatus to the manifold, and for controlling the flow of a medium through the manifold are also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    Not Applicable.  
         FEDERALLY SPONSORED RESEARCH  
         [0002]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The present invention relates to manifolds and, more particularly, to manifolds for use with heat exchanging appliances.  
           [0005]    2. Description of the Invention Background  
           [0006]    A variety of manifolds have been developed for integration into heat exchanging appliances used in heat exchanging applications. A typical heat exchanger includes a tube subassembly, a primary manifold and a secondary manifold.  
           [0007]    A conventional tube subassembly is comprised of a series of heat conducting tubes disposed in parallel with the first end of each tube connected to the primary manifold and the second end of each tube connected to the secondary manifold. The purpose of the tube subassembly is to transfer heat from a high temperature medium to a low temperature medium while preventing the high and low temperature mediums from contacting each other. To accomplish that heat transfer in such a tube assembly, either the high or low temperature medium is forced through the heat conductive tubes while the other medium is forced to flow past the external surfaces of the tubes in contact therewith. When the high temperature medium contacts the lower temperature tubes, heat is transferred from the high temperature medium to the tubes. Likewise, heat is transferred from the tubes to the lower temperature medium as the low temperature medium contacts the tubes. Thus, heat from the high temperature medium is transferred through the heat conductive tubes to the lower temperature medium.  
           [0008]    Although a variety of mediums have been used, one or both of the mediums may be in the form of a gas such as steam or air. Alternatively, one or both of the mediums may be a liquid such as water or glycol. In a swimming pool heating application, for example, air may be heated by direct contact with a flame or other heat source. The heated air then rises, contacting and heating the heat conductive tubes. Lower temperature pool water is simultaneously forced through the heat conductive tubes where it absorbs heat from the tubes. The pool water is circulated through the heat exchanger and a pool, thereby raising the temperature of the water in the pool.  
           [0009]    The heat conductive tubes of the tube subassembly are typically made of a metal, such as copper, brass, aluminum, iron or steel, that has a high heat transfer coefficient and can withstand prolonged exposure to both the high and low temperature mediums.  
           [0010]    Manifolds operate to direct a medium through the tubes of the tube subassembly. The primary manifold typically receives the medium from a piping system, distributes the medium to the tubes of the tube subassembly, and directs medium that has passed through the tube subassembly back to the piping system. Most primary manifolds, regardless of type, comprise a housing member having an inlet port defined by an inlet socket, an outlet port defined by an outlet socket, and an inner cavity. The inlet socket and the outlet socket are constructed for attachment to corresponding portions of a pipeline. Some sockets are provided with threaded connections, while others utilize a “slip fit” connection wherein a conduit that is a section of the pipeline is slidably received in the socket. The conduit is typically retained within the socket by an appropriate attachment medium or adhesive. For example, the conduit may be affixed to the socket by welding, soldering or gluing. A slip fit conduit may also be retained within the socket by mechanical means such as, for example, the use of flanges with gaskets and mechanical fasteners.  
           [0011]    The flow characteristics afforded by a manifold are generally dependent on the number of sections into which the manifold cavity is divided. The inner cavity of the primary and secondary manifolds may be divided into multiple chambers such that each chamber is in fluid communication with only a portion of the tubes of the tube subassembly. Such an arrangement permits fluid to be forced to flow from the inlet of the primary manifold, through selected tubes to the secondary manifold, and return to the primary manifold through other selected tubes. For example, the inner cavity of the primary manifold housing may be divided into two chambers wherein an inlet chamber is in fluid communication with the inlet port and several tubes such that medium entering the manifold through the inlet port is directed into those tubes; and an outlet chamber portion of the cavity is in fluid communication with the outlet port and several other tubes such that medium flowing through those tubes is returned to the piping system through the outlet port. A primary manifold having only those two cavity sections is commonly referred to as a “two-pass manifold,” and a heat exchanger incorporating such a manifold is commonly referred to as a “two-pass system,” because medium passes through tubes of the tube subassembly once after leaving the inlet chamber of the manifold cavity and then makes a second pass through other tubes before returning to the outlet chamber of the primary manifold.  
           [0012]    Other primary manifolds divide the cavity of the manifold into a third chamber that is in fluid communication only with a number of the tubes of the tube subassembly and not with either the inlet port or outlet port. The purpose of the third chamber is to direct fluid flowing into the chamber from several tubes, into other tubes carrying fluid away from the third chamber. A primary manifold having such a third chamber is commonly referred to as a “four-pass manifold,” and a heat exchanger incorporating such a manifold is referred to as a “four-pass system” because medium makes an additional pass through tubes of the tube subassembly when returning to the third chamber of the manifold and yet another pass through other tubes when leaving the third chamber.  
           [0013]    A secondary manifold may also be utilized to connect the ends of the tubes of the tube subassembly opposite the primary manifold. The secondary manifold may not contain a connection to the piping system but may simply be utilized to return the medium to the primary manifold. In a two-pass system, the secondary manifold ordinarily has a single chamber common to all of the tubes. In a four-pass system, the secondary manifold is usually divided into a leading chamber and a trailing chamber. In a four-pass system the medium typically makes a first pass, flowing from the inlet chamber of the primary manifold, through a first set of tubes, to the leading chamber of the secondary manifold; a second pass through a second set of tubes to the third chamber of the primary manifold; a third pass through a third set of tubes to the trailing chamber of the secondary manifold; and a fourth pass through a fourth set of tubes to the outlet chamber of the primary manifold.  
           [0014]    Two and four-pass systems offer different heating characteristics. Four-pass systems generally increase the temperature of the heated medium more than two-pass systems, while two-pass systems generally heat a greater volume of medium in a given time than do four-pass systems. Therefore, system dynamics usually dictate whether a two or four-pass heat exchanger is preferred in a particular system.  
           [0015]    While such manifolds can effectively direct flow from a pipeline through a tube subassembly, conventional manifold designs have various shortcomings. For example, in a pool heating system, pipeline pressures vary depending on pumping equipment utilized, frictional losses in the pipeline, system demands from other equipment drawing from the pipeline such as filters, and other factors. A conventional manifold may incorporate a bypass valve, located between the inlet and outlet chambers of the primary manifold to allow water to flow directly from the inlet chamber to the outlet chamber when the inlet pressure is greater than the pressure under which the heat exchanger is designed to operate. The bypass valve, however, has limited utility because it may only be adjusted by disassembling the manifold. Therefore, there is a need for a manifold incorporating an externally adjustable bypass valve.  
           [0016]    Connection of a conventional manifold to a piping system can be labor intensive and typically requires the employment of a person skilled in making such connections. Conventional connections are also difficult to repair when a failure occurs. Slip fit connections require each conduit to be properly cleaned and prepared, often requiring the use of specialized solutions. The piping connections must then be joined together by gluing or welding. Both glued and welded joints are susceptible to leakage and repair of such a leak is often difficult. Glued connections, for example, are typically not designed to be disconnected. Therefore, the components joined by a failed glued connection may not be repaired and must typically be removed and discarded. Threaded connections, likewise, require that each conduit be properly cleaned and prepared, and often require the use of specialized solutions. While a manifold may be pre-threaded, conduit typically must be cut to length and threaded at the installation site, which requires the use of specialized threading machinery. Disassembly and reassembly of threaded piping systems can also be very difficult because it necessitates the removal of the entire piping system to a point where a connection other than a standard threaded connection is utilized. Therefore, a need exists for a manifold connection that permits an unskilled person to connect a piping system to the manifold quickly and simply, and permits ease of removal and reconnection.  
           [0017]    Additionally, conventional manifolds are configured for use in either a two-pass or a four-pass system but not both. Meeting the requirements of different heat exchanging systems is made cumbersome and expensive by the need to manufacture and stock both two and four-pass manifolds to meet varying system requirements. Therefore, there is a need for manifolds that may be utilized in both two and four-pass heat exchanging systems.  
           [0018]    It is often desirable to include an optional sensor, such as a temperature or pressure sensor, in a manifold. A manifold that includes the appropriate number of sensor ports must be utilized in such applications. Where no optional sensors are to be utilized at the manifold, it may be preferable to utilize a manifold having no sensor ports to minimize the risk that medium will leak from the manifold. Once again, the necessity of manufacturing and stocking multiple manifolds having varying port configurations is cumbersome and expensive. Therefore, a need exists for a manifold that can be easily configured for the inclusion of sensors.  
           [0019]    It is also often desirable to control the flow of medium in a manifold in relation to the temperature of the medium. A certain conventional manifold utilized a thermostatic valve, located in the pipeline external to the manifold, to regulate the flow of medium as the temperature of the medium changes. Thus, a desired amount of heat may be introduced into the pool regardless of fluctuations in the amount of heat added to the pool water in the heat exchanging appliance. Additional labor is, however, required to install the thermostatic valve in the pipeline. Therefore, there is a need for a thermostatic valve assembly that may be incorporated into a manifold.  
         SUMMARY OF THE INVENTION  
         [0020]    The present invention is directed to a manifold for a heat exchanging appliance. The manifold includes several features that allow the manifold to be used in a wide variety of applications.  
           [0021]    An externally adjustable bypass valve is provided. The bypass valve permits a medium passing into a chamber of a housing to selectively bypass the chamber when the medium achieves a preselected pressure within the chamber. The bypass valve includes a poppet movably supported within the chamber between sealing engagement with an outlet in the chamber and non-sealing engagement with the outlet. The bypass valve also includes an adjustable actuation assembly attached to the poppet and protruding from the housing for external access. The actuation assembly selectively applies a biasing force to the poppet to retain the poppet in sealing engagement with the outlet until the medium pressure exceeds the biasing force.  
           [0022]    The bypass valve may include a shaft having a proximal end extending through an appliance housing, a distal end, a stop, a threaded follower segment intermediate the distal end and the stop, and a key in the proximal end of the shaft to facilitate rotation of the shaft. The bypass valve may also include a follower having at least one anti-rotation surface for engaging the housing and a threaded hole for engaging the threaded follower segment of the shaft, whereby the follower moves along the threaded follower segment of the shaft when the shaft is rotated. The bypass valve may further comprises a biasing member disposed intermediate the follower and the poppet and a removable plug to facilitate removal of the bypass valve from the manifold.  
           [0023]    A method of controlling the pressure in a high pressure chamber with respect to the pressure in a low pressure chamber in fluid communication with the high pressure chamber is also provided. The method includes biasing a poppet between the high and low pressure chambers and varying the biasing force applied to the poppet from outside the high and low pressure chambers.  
           [0024]    A compression fitting for connecting a conduit and a piping socket is also provided. The compression fitting includes a compression nut having a compression end and a threaded surface for engaging a threaded surface of the piping socket. The compression fitting also includes an inner ring having a retaining portion and an outer ring. The inner ring is disposed on the conduit intermediate the compression end of the compression nut and the piping socket and the outer ring is disposed on the retaining portion of the inner ring. The outer ring may optionally include one or more compression joints.  
           [0025]    A flow cup is further provided. The flow cup includes a flow cup body having an endless wall defining a chamber. The flow cup may be placed in a manifold to add one or more passes to the heat exchanging appliance.  
           [0026]    An apparatus for conveying the temperature of a medium in a nonconductive housing to a temperature sensor is also provided. The apparatus includes a heat conductive stud disposed through a hole in the housing and a fastener to retain the stud in the hole. The apparatus may also include a sensor socket formed on the housing for containing the temperature sensor and maintaining the temperature sensor in proximate relationship to the stud. In addition the apparatus may include a sensor cover, for placement on the rim of the sensor socket, to enclose the sensor in the sensor socket.  
           [0027]    A manifold having a blind threaded hole for engaging an insertion apparatus is also provided. The blind threaded hole includes a fitting engaging portion extending from the manifold and a portion of the manifold enclosed by the fitting engaging portion, wherein the portion of the manifold enclosed by the fitting engaging portion may be removed and a fitting attached to the fitting engaging portion.  
           [0028]    A thermostatic valve assembly is further provided. The thermostatic valve assembly includes a thermostatic valve that operates to selectively permit medium flow and a biasing member urging the thermostatic valve toward a port to restrict flow around the thermostatic valve. The thermostatic valve assembly may also include an interface for selectively retaining and orienting the thermostatic valve assembly.  
           [0029]    The present invention offers the feature of permitting a bypass valve to be removed or adjusted without disassembling the manifold. Another feature of the present invention is to permit an unskilled person to connect a piping system to the manifold quickly and simply and to further permit ready removal and reconnection of the piping system. The present invention also offers the feature that permits a manifold to be used in either a two- or four-pass system. The present invention further provides optional sensor interface features. In addition the present invention provides a feature whereby the flow of medium through the manifold is internally controlled in relation to the temperature of the medium in the manifold. Accordingly, the present invention provides solutions to the shortcomings of conventional manifold arrangements. Those of ordinary skill in the art will appreciate, however, that these and other details, features and advantages will become further apparent as the following detailed description proceeds. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0030]    In the accompanying Figures, there are shown present preferred embodiments of the invention wherein like reference numerals are employed to designate like parts and wherein:  
         [0031]    [0031]FIG. 1 is an exploded assembly view of a heat exchanger of the present invention;  
         [0032]    [0032]FIG. 2 is a perspective view of the heat exchanger of FIG. 1;  
         [0033]    [0033]FIG. 3 is an exploded assembly view of the primary manifold of the heat exchanger shown in FIGS. 1 and 2;  
         [0034]    [0034]FIG. 4 is a perspective view of the tube assembly interconnect member and bypass valve employed in the primary manifold of FIG. 3;  
         [0035]    [0035]FIG. 5 is an enlarged cross-sectional view of the bypass valve of FIG. 4 and the section of the primary manifold of FIG. 4 in which the bypass valve is installed, taken along line V-V in FIG. 4;  
         [0036]    [0036]FIG. 6 is an exploded assembly view of the bypass valve of FIGS.  3 - 5 ;  
         [0037]    [0037]FIG. 7 is a side view of the shaft of the bypass valve of FIG. 6;  
         [0038]    [0038]FIG. 8 is an end view of the shaft of FIGS. 6 and 7;  
         [0039]    [0039]FIG. 9 is a front perspective view of the poppet of the bypass value of FIG. 6;  
         [0040]    [0040]FIG. 10 is a rear perspective view of the poppet of FIG. 9;  
         [0041]    [0041]FIG. 11 is a front elevational view of the poppet of FIGS. 9 and 10;  
         [0042]    [0042]FIG. 12 is a rear view of the poppet of FIGS.  9 - 11 ;  
         [0043]    [0043]FIG. 13 is a cross-sectional view of the poppet of FIG. 12, taken along line XIII-XIII in FIG. 12;  
         [0044]    [0044]FIG. 14 is a cross-sectional view of the poppet of FIG. 12, taken along line XIV-XIV in FIG. 12;  
         [0045]    [0045]FIG. 15 is a front elevational view of the follower of the bypass valve of FIG. 6;  
         [0046]    [0046]FIG. 16 is a rear view of the follower of FIG. 15;  
         [0047]    [0047]FIG. 17 is a cross-sectional view of the follower of FIG. 15, taken along line XVII-XVII in FIG. 15;  
         [0048]    [0048]FIG. 18 is a rear perspective view of the plug of the bypass value of FIG. 6;  
         [0049]    [0049]FIG. 19 is a front perspective view of the plug of FIG. 18;  
         [0050]    [0050]FIG. 20 is a front view of the plug of FIGS. 18 and 19;  
         [0051]    [0051]FIG. 21 is a side elevational view of the plug of FIGS.  18 - 20 ;  
         [0052]    [0052]FIG. 22 is a rear view of the plug of FIGS.  18 - 21 ;  
         [0053]    [0053]FIG. 23 is a cross-sectional view of the plug of FIG. 20, taken along line XXIII-XXIII in FIG. 20;  
         [0054]    [0054]FIG. 24 is a cross-sectional view of the plug of FIG. 20, taken along line XXIV-XXIV in FIG. 20;  
         [0055]    [0055]FIG. 25 is a cross-sectional view of the bypass valve of FIG. 6, taken along line XXV-XXV of FIG. 6;  
         [0056]    [0056]FIG. 26 is an exploded assembly view of the primary manifold of FIGS.  1 - 3  and a compression fitting of the present invention;  
         [0057]    [0057]FIG. 27 is an enlarged cross-sectional view of the manifold and compression fitting of FIG. 26, taken along line XXVII-XXVII in FIG. 26, illustrating the compression fitting in attachment with the manifold;  
         [0058]    [0058]FIG. 28 is an exploded assembly view of the sealing member of the compression fitting of FIGS. 26 and 27;  
         [0059]    [0059]FIG. 29 is a cross-sectional view of the sealing member of FIG. 28, taken along line XXIX-XXIX of FIG. 28;  
         [0060]    [0060]FIG. 30 is an enlarged side view of an compression joint of the outer ring of FIG. 28;  
         [0061]    [0061]FIG. 31 is an exploded assembly view of the primary manifold of FIGS.  1 - 3  and a flow cup of the present invention;  
         [0062]    [0062]FIG. 32 is a rear elevational view of the manifold and flow cup of FIG. 31 with the flow cup installed therein;  
         [0063]    [0063]FIG. 33 is a front perspective view of the flow cup of FIGS. 31 and 32;  
         [0064]    [0064]FIG. 34 is a rear perspective view of the flow cup of FIGS.  31 - 33 ;  
         [0065]    [0065]FIG. 35 is a rear elevational view of the flow cup of FIGS.  31 - 34 ;  
         [0066]    [0066]FIG. 36 is a cross-sectional view of a temperature sensing apparatus of the present invention installed in a manifold;  
         [0067]    [0067]FIG. 37 is a cross-sectional view of a dual temperature sensing apparatus of the present invention installed in a manifold;  
         [0068]    [0068]FIG. 38 is a perspective view of the primary manifold of FIGS.  1 - 3  incorporating the sensor sockets of FIGS. 36 and 37;  
         [0069]    [0069]FIG. 39 is a rear perspective view of the primary manifold of FIG. 38;  
         [0070]    [0070]FIG. 40 is an enlarged rear view of the dual sensor socket of FIG. 39;  
         [0071]    [0071]FIG. 41 is a front perspective view of the primary manifold of FIGS. 38 and 39;  
         [0072]    [0072]FIG. 42 is an enlarged front view of the dual sensor socket of FIG. 41;  
         [0073]    [0073]FIG. 43 is an enlarged front view of the dual sensor socket of FIGS.  38 - 42 ;  
         [0074]    [0074]FIG. 44 is an enlarged side elevational view of the dual sensor socket of FIGS.  38 - 43 ;  
         [0075]    [0075]FIG. 45 is an enlarged rear view of the dual sensor socket of FIGS.  38 - 44 ;  
         [0076]    [0076]FIG. 46 is a cross-sectional view of the dual sensor socket of FIG. 43, taken along line XLVI-XLVI of FIG. 43;  
         [0077]    [0077]FIG. 47 is an exploded assembly view of the primary manifold of FIG. 38 and temperature sensors and sensor covers of the present invention;  
         [0078]    [0078]FIG. 48 is an enlarged exploded assembly view of the temperature sensing apparatus of FIG. 47;  
         [0079]    [0079]FIG. 49 is an enlarged exploded assembly view of the dual temperature sensing apparatus of FIG. 47;  
         [0080]    [0080]FIG. 50 is a cross-sectional view of a blind threaded hole of the present invention in a manifold;  
         [0081]    [0081]FIG. 51 is a cross-sectional view of a tapped blind threaded hole of the present invention in a manifold; and  
         [0082]    [0082]FIG. 52 is an exploded assembly view of the primary manifold of FIGS.  1 - 3  and a thermostatic valve assembly of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0083]    Referring now to the drawings for the purpose of illustrating present preferred embodiments of the invention only and not for the purpose of limiting the same, FIG. 1 illustrates an exploded perspective view of a heat exchanging appliance  30  including a primary manifold  32  constructed in accordance with the present invention. FIG. 2 illustrates an assembled view of the same heat exchanger  30  illustrated in FIG. 1. Those skilled in the art will recognize that many heat exchanger embodiments may be utilized in cooperation with the manifold  32  of the present invention and will be able to incorporate the manifold  32  into heat exchanging appliances other than those illustrated herein. In addition to the manifold  32  constructed in accordance with the present invention, the heat exchanger  30  embodiment illustrated in FIGS. 1 and 2 includes a secondary manifold  34  and a heat transferal subassembly  36  such as, for example, a tube subassembly.  
         [0084]    The heat transferal subassembly  36  illustrated, includes a plurality of tubes  38 , a pair of connecting brackets  40 , and a pair of manifold gaskets  42 . The primary manifold  32  and secondary manifold  34  may be connected to the heat transferal subassembly  36  by way of capscrews  44 . The capscrews  44  may each pass through an aperture  48  in the manifold ( 32 ,  34 ), and an aperture  50  in the manifold gasket  42 , to engage a threaded hole  52  in the connecting bracket  40 . Sleeves  54  may be incorporated into the manifold apertures  48  to prevent damage to the manifold ( 32 ,  34 ) that might otherwise occur when the capscrews  44  are tightened directly against the manifold ( 32 ,  34 ).  
         [0085]    [0085]FIG. 3 illustrates an exploded assembly view of an embodiment of the primary manifold  32  constructed in accordance with the present invention. The manifold housing  55  may be formed in one piece to minimize manufacturing costs, or may be formed in more than one piece to facilitate access to inner portions of the manifold  32  or for ease of manufacturing. The embodiment illustrated is formed in two pieces, a piping system interconnect member  56  and a tube assembly interconnect member  58 .  
         [0086]    The piping system interconnect member  56  may include an inlet piping socket  60  that forms an inlet port  62 , an outlet piping socket  64  that forms an outlet port  66 , an inlet chamber  68 , an outlet chamber  70  an endless outer rib  72  and an endless inner rib  74 . The piping system interconnect member  56  may also include a plurality of bolt holes  76  that correspond to bolt receptacles  78  in the tube assembly interconnect member  58  for interconnection of the piping system interconnect member  56  and the tube assembly interconnect member  58 .  
         [0087]    The tube assembly interconnect member  58  may also include an inlet chamber  68 ′ and an outlet chamber  70 ′ or portions of an inlet chamber  68 ′ and an outlet chamber  70 ′ that correspond to portions of the inlet and outlet chambers  68  and  70  of the piping system interconnect member  56 . The tube assembly interconnect member  58  also includes a cavity  80  which collects medium from the inlet chamber  68  and distributes the medium to the heat transferal subassembly  36 . A section, such as, for example, the tube assembly interconnect surface  82  of FIG. 3, suitable for connecting the manifold to a heat transferal subassembly  36 , is also provided in the tube assembly interconnect member  58 . A plurality of manifold apertures  48  that correspond to threaded holes  52  in the heat transferal subassembly  36  may be provided in the tube assembly interconnect surface  82  for interconnecting the manifold  32  to the heat transferal subassembly  36 .  
         [0088]    A variety of sensing devices, such as, for example, temperature and pressure sensors, and control devices, such as, for example, thermostatic valves and bypass valves, may also be provided in the manifold  32  of the present invention.  
         [0089]    [0089]FIG. 3 illustrates one such bypass valve  84  which may be provided in a manifold  32  to permit medium present in the inlet chamber  68  to pass directly to the outlet chamber  70  without passing through the heat transferal subassembly  36 . The bypass valve  84  may be provided to prevent the heat transferal subassembly  36  from being damaged by differential pressure between the medium in the inlet chamber  68  and the medium in the outlet chamber  70  that is greater than the differential pressure at which the heat transferal subassembly  36  is designed to operate.  
         [0090]    [0090]FIG. 4 illustrates the bypass valve  84  operably disposed in the manifold  32  and FIG. 5 depicts a cross-sectional view of a section of the manifold  32  with the bypass valve  84  operably disposed in the manifold  32 .  
         [0091]    [0091]FIG. 6 illustrates an exploded assembly view of the bypass valve  84  which includes a shaft  86 , a follower  88 , a poppet  90 , and a biasing member  92 . The bypass valve  84  may also include a plug  94  for removably retaining the bypass valve  84  in the manifold  32 , an adjustment nut  96  for clamping the bypass valve  84  against the manifold housing  55  or plug  94 , a retaining member  98  to limit movement of the poppet  90 , a plug gasket  100  for sealing between the plug  94  and the manifold housing  55 , a shaft gasket  102  for sealing between the shaft  86  and the plug  94  or manifold housing  55 , and a follower washer  104  that may be placed between the follower  88  and the biasing member  92  to prevent the biasing member  92  from impinging on the follower  88 .  
         [0092]    [0092]FIG. 7 illustrates a side view of the shaft  86  and FIG. 8 illustrates the shaft  86  as viewed from the proximal end. The shaft  86  is constructed so that its proximal end  106  can extend through the manifold housing  55 . The proximal end  106  may be keyed, as illustrated in FIG. 8, so that the shaft  86  may be engaged by a tool, such as, for example, a standard screwdriver, and rotated to adjust the force applied to the poppet  90  by the biasing member  92  without disassembly of the manifold  32 . The shaft  86  also has a stop  108  such as, for example, a collar extending axially from the shaft, near its proximal end  106 . The stop  108  prevents the shaft  86  from extending through the manifold housing  55  beyond the stop  108 . The external surface  109  of the proximal end  106  of the shaft  86 , may include a threaded segment so that the adjustment nut  96  may be utilized to retain the shaft  86  in place against the manifold  32  when the proximal end  106  is extended through the manifold housing  55 . When the adjustment nut  96  is tightened, it also prevents rotation of the shaft  86 , thereby preventing movement of the follower  88  along the shaft  86 . The shaft  86  also includes a threaded follower segment  110  intermediate the stop  108  and the distal end  112  of the shaft  86 . Near its distal end  112 , the shaft  86  may include a poppet retaining member engagement portion, such as, for example, an endless slot  114  extending around the shaft. A retaining member  98 , such as, for example, a conventional or commercially available retaining ring may engage the endless slot  114  to limit movement of the poppet  90  on the shaft  86 .  
         [0093]    FIGS.  9 - 14  illustrate a poppet  90 , constructed in accordance with the present invention. As may be seen in FIGS. 4 and 5, the poppet  90  is adapted to engage a seat  116  of a dividing wall  118  surrounding a bypass port  120  between the inlet chamber  68  and outlet chamber  70 . As may be seen in FIGS. 9 and 10, the poppet  90  includes a flow control surface  122 , a shaft passage  124 , a seat engaging surface  126 , and a biasing member engaging section  125 . The flow control surface  122  may be formed in many configurations to achieve desired flow characteristics through the bypass port  120 . The flow control surface  122  may, for example, be conical with linear, convex or concave sides to provide, for example, a linear relationship between poppet  90  movement and flow through the bypass port  120 . The shaft  86  is operably received in the shaft passage  124  which may be keyed to prevent rotation of the poppet  90  on the shaft  86 . The seat engaging surface  126  engages the seat  116  of the dividing wall  118  to prevent flow through the bypass port  120  until an increase in differential pressure between the inlet chamber  68  and the outlet chamber  70 , thereby moving the seat engaging surface  126  away from the seat  116  displaces the poppet  90 . Thus, the medium is permitted to flow through the bypass port  120  when differential pressure increases a sufficient amount to overcome the force generated by the biasing member  92 . The biasing member engaging section  125  of the poppet  90  is provided as an interface for the biasing member  92 .  
         [0094]    FIGS.  15 - 17  illustrate a follower  88  constructed in accordance with the present invention. As illustrated in FIG. 15, the follower  88  has a threaded hole  128  and an anti-rotational surface  130 . The threaded hole  128  is configured to rotationally engage the threaded follower segment  110  of the shaft  86 . The anti-rotational surface  130  may, for example, have two opposing bifurcations  132  for engagement with standing ribs  134  (illustrated in FIG. 25) on the manifold housing  55  or plug  94 .  
         [0095]    FIGS.  18 - 24  illustrate a removable plug  94  that may optionally be incorporated into the manifold  32  to facilitate removal of the bypass valve  84 . As may be seen in FIGS. 18 and 19, the plug  94  may include a pair of linear standing ribs  134 , a shaft retaining member  136 , a manifold housing engagement portion  138 , and a gripping portion  140  for use when rotating the plug  94 . The standing ribs  134  engage the bifurcations  132  of the follower  88  to prevent rotation of the follower  88 . The shaft retaining member  136  may define a shaft retaining passage  142  through which the proximal end  106  of the shaft  86  projects. The shaft retaining member  136  may also include a stop engaging surface  144  and an opposing nut engaging surface  146  such that the shaft may be disposed through the shaft retaining passage  142  until the stop  108  engages the stop engaging surface  144 , and the adjustment nut  96  may be threaded onto the proximal end  106  of the shaft  86  to engage the nut engaging surface  146 , thereby clamping the shaft  86  to the plug  94 . The manifold housing engagement portion  138  may include, for example, a threaded surface  148  as illustrated in FIG. 18. The threaded surface  148  may be configured to sealingly engage the manifold housing  55  when the removable plug  94  is screwed into the housing  55 . The gripping portion  140  provides a structure that may be engaged by a tool. The gripping portion  140  may, for example, include an endless wall having six linear sides or a hex shaped projection extending from the plug  94 . The tool may be, for example, a wrench, which facilitates rotation of the plug  94  to engage the plug  94  and the manifold housing  55 .  
         [0096]    FIGS.  20 - 22  illustrate top side and bottom views of the plug  94 , respectively. FIGS. 23 and 24 illustrate cross-sectional views of the plug illustrated in FIGS.  18 - 22 .  
         [0097]    [0097]FIG. 25 illustrates a cross-sectional view of an embodiment of the bypass valve  84  constructed in accordance with the present invention. A plug gasket  100  such as, for example, an O-ring, may be provided between the plug  94  and manifold housing  55  to facilitate a fluid- tight seal between the plug  94  and the manifold housing  55 . A shaft gasket  102 , which may also be an O-ring, may be provided between the plug  94  and shaft  86  or the housing  55  and shaft  86  in applications in which a plug  94  is not utilized, to facilitate a fluid-tight seal between the plug  94  or housing  55  and shaft  86 .  
         [0098]    Referring to the embodiment illustrated in FIG. 25, the poppet  90  is disposed on the distal end  112  of the shaft  86 . The retaining member  98  includes a retaining ring in this embodiment and is disposed in the slot  114  at the distal end  112  of the shaft  86  to limit travel of the poppet  90 . In this embodiment, the biasing member  92  comprises a coil spring. The biasing member  92  rests against the biasing member engagement section  125  of the poppet  90 , thereby forcing the poppet  90  against the dividing wall seat  116  to prevent medium flow between the inlet chamber  68  and outlet chamber  70 . The biasing member  92  extends from the biasing member engagement section  125  of the poppet  92  to the follower  88 . In the embodiment illustrated, a follower washer  104  is disposed between the biasing member  92  and follower  88  to prevent follower wear that may be caused by the biasing member  92 . The follower  88  is threaded onto the threaded follower segment  110  of the shaft  86  and the bifurcations  132  are engaged with the standing ribs  134  of the plug  94 . The proximal end  106  of the shaft  86  extends through the plug  94  and is clamped thereto by the adjustment nut  96 .  
         [0099]    In operation, as shown in FIG. 5, the bypass valve  84  is inserted into the manifold  32  so that the seat engaging surface  126  of the poppet  90  is forced against the dividing wall seat  116  to prevent medium from flowing through the bypass port  120 . When pressure in the high pressure inlet chamber  68 ′ exceeds the sum of the pressure in the low pressure outlet chamber  70 ′ and the force applied to the poppet  90  by the biasing member  92 , the poppet  90  is forced away from the distal end  112  of the shaft  86  and the dividing wall seat  116 , thereby permitting medium to flow directly from the inlet chamber  68 ′ to the outlet chamber  70 ′, without first passing through the heat transferal subassembly  36 .  
         [0100]    The force that is applied to the poppet  90  by the biasing member  92  may be adjusted by rotating the shaft  86 . It is convenient to rotate the shaft  86  at the keyed proximal end  106  because that portion of the shaft extends through the manifold housing  55  and is, therefore, easily accessible. When the shaft  86  is rotated, the follower  88 , which is prevented from rotating by the anti-rotational surface  130 , moves along the threaded follower segment  110 . When the shaft  86  is rotated such that the follower  88  moves toward the proximal end  106  of the shaft  86 , the force applied to the poppet  90  by the biasing member  92  is reduced. Conversely, when the shaft  86  is rotated such that the follower  88  moves toward the distal end  112  of the shaft  86 , the force applied to the poppet  90  by the biasing member  92  is increased. After the biasing member  92  has been adjusted to the desired force setting, the adjustment nut  96  may be tightened to prevent further rotation of the shaft  86 . Thus, the biasing force applied to the poppet  90  may be adjusted from outside of the manifold  32  of the present invention.  
         [0101]    FIGS.  26 - 30  illustrate a compression fitting  150  of the present invention for connecting the manifold  32  to a conduit. FIG. 26 illustrates a manifold  32  of the present invention and an exploded view of the compression fitting  150 . The compression fitting includes a compression nut  152  and a sealing member  154 . The inlet piping socket  60  and outlet piping socket  64  may each be provided with a smooth internal conduit receiving surface  156 , a conduit curb  158  (illustrated in FIG. 27), a male thread  160  on the outer surface  162  of the piping socket ( 60 ,  64 ) and a terminal surface  164 . Such piping sockets ( 60 ,  64 ) are suitable for connection to a conduit  166 , that is a portion of the conduit, by way of the compression fitting  150 .  
         [0102]    [0102]FIG. 27 illustrates a cross-sectional view of the compression fitting  150  in operable engagement with one of the piping sockets ( 60 ,  64 ) and a conduit  166 . The compression nut  152  includes an open end  180 , a compression end  182 , an inner surface  184 , and an outer surface  186 . The compression end  182  of the compression nut  152  is provided with an annular hole  188  sized to permit a conduit  166  to be placed through the hole  188 . The inner surface  184  of the compression nut  152  may include a female threaded section  190  and an angled section  192 . The outer surface  186  of the compression nut  152  may be configured to be gripped with a tool or by hand. The outer surface  186  may, for example, have flat sections (not illustrated) that may be engaged by a tool such as, for example, a wrench, or the outer surface may, for example, have upstanding ridges  194  that promote gripping of the compression nut  152  by hand or tool.  
         [0103]    [0103]FIG. 28 illustrates an exploded assembly view of the sealing member  154  and FIG. 29 depicts the sealing member  154  in cross-section. As illustrated in FIGS. 28 and 29, the sealing member may be comprised of an inner ring  168  and an outer ring  170 . The inner ring  168  may have an inner surface  172  and an outer surface  174 , the outer surface  174  having an upstanding lip  176  on each side  177 . A retaining portion  173 , is defined by the outer surface  174  and upstanding lips  176  of the inner ring  168 . The inner surface  172  of the inner ring  168  may be sized to engage the outer surface of the conduit  166 . The inner ring  168  may be made from a material that is somewhat compressible such as, for example, a rubber or elastomer which may be an EPDM compound. The outer ring  170  may be disposed on the retaining portion  173  of the inner ring  168  intermediate the upstanding lips  176  of the outer surface  174 . The outer ring  170  may be made from a deformable material such as, for example, a polymer which may be a polyamide such as nylon, and may include compression joints  178 . The compression joints may be V-shaped segments in the outer ring  170 . The V-shaped compression joint  179  may be compressed such that the sides become parallel to permit the outer ring  170  to contract when, for example, the outer ring  170  is compressed against the compression nut  152 .  
         [0104]    In operation, the compression nut  152  may be slidably disposed on the conduit  166  with the open end  180  of the compression nut  152  directed toward an open end of the conduit  166 . The sealing member  154  may be slidably disposed on the conduit  166  such that the sealing member  154  is received within the open end  180  of the compression nut. The conduit  166  may be slidably received in the piping socket ( 60 ,  64 ) until it contacts the conduit curb  158 . The sealing member  154  may be moved along the conduit  166  until it contacts the terminal surface  164  of the piping socket ( 60 ,  64 ) and the compression nut  152  may be threaded onto the piping socket ( 60 ,  64 ). The compression nut  152  may be tightened by utilizing a tool, such as, for example, a wrench, or may be tightened by hand. When the compression fitting  150  is attached to the piping socket ( 60 ,  64 ), the sealing member  154  is compressed between the piping socket ( 60 , 64 ), compression nut  152 , and conduit  166 , thereby creating a seal that prevents the medium flowing through the conduit  166  from bypassing the sealing member  154 . More specifically, the sealing member  154  is in lateral contact with the terminal surface  164  of the piping socket ( 60 ,  64 ) and the inner surface  172  of the compression end  182  of the compression nut  152  in this configuration. The sealing member  154  is also in longitudinal contact with the angled section  192  of the inner surface  172  of the compression nut  152  in this configuration. The contact of the sealing member  154  with those surfaces, under compressive force, prevents the medium from leaking at the joint so formed.  
         [0105]    The use of the compression fitting permits the conduit  166  to be easily connected to, or disconnected from the manifold  32 . Connecting or disconnecting may be accomplished without disconnecting other joints in the conduit  166 , and a tight seal may typically be achieved without the use of any specialized tools or solutions. Furthermore, if a leak occurs at the joint connected by way of the compression fitting  150 , the leak may often be repaired by simply rotating the compression nut  152  into tighter engagement with the piping socket ( 60 ,  64 ).  
         [0106]    FIGS.  31 - 35  illustrate a flow cup  196  of the present invention. FIG. 31 depicts an exploded assembly view of the flow cup  196  and the manifold  32  and FIG. 32 illustrates the manifold  32  having the flow cup  196  inserted within the cavity  80  of the manifold  32 . FIGS.  33 - 35  illustrate various views of the flow cup  196  without the manifold  32 . The flow cup  196  may comprise a cup shaped body having a base  198  and an endless wall  200  ending in a rim  202  and defining an additional chamber section  204 . One or more flow cups  196  may be inserted into the primary manifold  32  or the secondary manifold to add one or more additional chamber sections to the cavity  80  of the primary manifold  32  or secondary manifold. For example, a two-pass manifold may be converted to a four-pass manifold by inserting a flow cup  196  into the cavity  80 . The flow cup  196  may be inserted into the manifold  32  such that the endless wall  200  separates the portion of the cavity  80  falling within the all  200  from the portion of the cavity  80  falling outside of the wall  200 . The rim  202  of the flow cup  196  may sealingly contact the heat transferal subassembly  36  so that medium may flow into the additional chamber section  204  formed by the flow cup  196  from at least one inlet flow path, such as, for example, one or more tubes  38  of the heat transferal subassembly  36  and medium may flow out of the additional chamber section  204  by way of an outlet flow path, such as, for example, one or more tubes  38  of the heat transferal subassembly  36 .  
         [0107]    The present invention also includes a method of adding passes to a heat exchanging appliance by adding one or more removable flow cups  196  or dividers (not shown) to the primary manifold  32  or the secondary manifold of the heat exchanging appliance. For example, a flow cup  196  may be added to a manifold cavity  80  to divide the cavity  80  into at least one additional chamber  204 . Each chamber  204  that is not in fluid communication with either the inlet port  62  or the outlet port  66  may be placed in fluid communication with at least one inlet flow path, such as, for example, a tube  38  of the heat transferal subassembly  36 , and at least one outlet flow path, such as, for example, a tube  38  of the heat transferal subassembly  36 , so that the medium will circulate through each chamber ( 68 ,  70 .  204 ). Thus a two-pass manifold may be converted into a four-pass manifold. The flow cup  196  or divider may sealingly engage the heat transfer subassembly  36  and divide the cavity  80  of the manifold  32  to prevent medium from flowing from one chamber ( 68 ,  70 .  204 ) of the manifold  32  to another chamber ( 68 ,  70 .  204 ) of the manifold  32 .  
         [0108]    FIGS.  36 - 49  illustrate an apparatus for sensing the temperature of a medium in a non-conductive housing  210 . The apparatus includes a heat conductive stud  206  disposed through a hole  208  in the housing  210  of, for example, a polymer manifold  32 , and secured by a fastener such as, for example, a nut  212 . The stud  206  may have a shaft  214  having a male thread  216  for complimentary engagement with a female thread  218  on the nut  212 . The stud  206  may also have a head  220  having a key  222 , such as, for example, a slot, so that a tool, such as, for example, a standard screwdriver, may engage the stud  206  to rotate the stud  206  in relation to the nut  212 . The shaft  214  of the stud  206  may also have a hollow  215  to permit the sensed medium to flow into the stud  206 .  
         [0109]    The heat conductive stud  206  and nut  212  may be fabricated from many heat conducting materials including steel, iron, copper, stainless steel, brass and bronze. The skilled artisan will readily appreciate that the materials from which the stud  206  and nut  212  are fabricated may be advantageously selected based on their compatibility with the medium being handled and the environment, including, for example, the pressure and temperature conditions, to which the stud  206  and nut  212  will be exposed.  
         [0110]    The housing  210  may additionally have an inner surface  226  having a protrusion  228  that engages the nut  212  to prevent rotation of the nut  212 , and a sensor socket  230  in which a commercially available temperature sensor  232  such as that temperature sensor manufactured by CEMCO of Tennessee under Model No. 4302538 may be disposed. A sensor cover  234  may also be provided over the sensor socket  230 , to hold the temperature sensor  232  in place, to protect the temperature sensor  232 , and to minimize heat transfer between the socket  230  and ambient air. The sensor cover  234  may be attached to the housing  210  by many advantageous means including, for example, direct engagement between the cover  234  and the housing  210 , or attachment by one or more screws  236 .  
         [0111]    The sensor cover  234  may be fabricated from many materials including metal, plastic or rubber. A metal or plastic sensor cover may include a rubber portion to seal the sensor socket  230  to prevent outside contaminants from contacting the temperature sensor  232 .  
         [0112]    A washer  224  may optionally be placed on the shaft  214  of the stud  206  before the stud shaft  214  is placed through the hole  208  in the housing  210  to facilitate a seal between the stud  206  and the housing  210 . The washer  224  may be fabricated from many different materials including, for example, a fibrous material which may be advantageous when employing a metal stud  206  and a polymer housing  210 .  
         [0113]    In operation, the nut  212  may be placed on the inner surface  226  of the housing  210  adjoining the hole  208 . The stud  206  may be placed through the hole  208  in the housing  210  and the shaft  214  of the stud  206  may be threaded into the nut  212 . A temperature sensor  232  may be disposed in a sensor socket  230  formed on the manifold housing  210  with the sensing surface  238  of the temperature sensor  232  contacting the stud  206 . In this way, the temperature sensor  232  is isolated from the medium which may contain materials that could damage the temperature sensor  232 . The temperature of the medium is readily sensed by the temperature sensor  232  because heat from the medium is conducted through the heat conductive stud  206 . The hollow  215  of the stud  206  permits the medium to be in close proximity to the temperature sensor  232  to minimize the amount of time required for the temperature sensor  232  to sense a change in medium temperature. The sensor  232  may then provide a control signal to a controller or a gauge to provide an indication of the fluid temperature. The use of the stud  206  as described hereinabove also prevents leakage that commonly occurs when a conventional temperature sensor is inserted through the housing  210  to directly contact the medium.  
         [0114]    [0114]FIGS. 50 and 51 illustrate a blind threaded hole  238  of the present invention. The blind threaded hole  238  includes a fitting engaging portion  240  for complimentary engagement with a fitting such as, for example, a control device or sensor (not shown). The fitting engaging portion  240  may include a wall  242  projecting from the housing  210 . The wall  242  may furthermore have a female thread  244  for engagement with a fitting having a male thread (not shown). As FIG. 50 illustrates, when the housing  210  is manufactured, the portion of the housing  210  enclosed by the fitting engaging portion wall  242  may not contain an opening  248 . If the user desires to include a device utilizing a fitting at the blind threaded hole  238 , the portion of the housing  210  enclosed by the fitting engaging portion wall  242  may be breached by, for example, drilling the housing  210 , to form an opening  248 . A breached embodiment is illustrated in FIG. 51. The fitting may be threaded into the fitting engaging portion  240  of the breached blind threaded hole  238  to contact the medium contained within the housing  210 .  
         [0115]    [0115]FIGS. 3 and 26 illustrate the blind threaded hole  238  incorporated into a manifold  32  at a location at which the inlet medium pressure may be sensed or a pressure relief valve may be utilized. To utilize a control or sensing device (not shown), the portion of the housing  210  enclosed by the fitting engaging portion wall  242  is breached and a fitting is threaded into the fitting engaging portion  240  such that the medium may be incident on the control or sensing device through the opening  248 .  
         [0116]    [0116]FIG. 52 illustrates an exploded assembly view of the manifold  32  of the present invention including a thermostatic valve assembly  250 . The thermostatic valve assembly  250  includes a thermostatic valve  254  and a biasing member  256  such as, for example, a coil spring. The thermostatic valve  254  contains a thermal expansion material known in the thermostatic valve art which operates the thermostatic valve  254  to permit or restrict flow as the temperature of the expansion material varies. A certain conventional thermostatic valve  254  that may be utilized in the present invention operates to permit flow through the thermostatic valve  254  when heated and to restrict flow through the thermostatic valve  254  when cooled. Alternately, other thermostatic valves having different operating characteristics may be employed in the present invention.  
         [0117]    To prevent flow around the thermostatic valve  254 , the valve  254  may be sealed to a port such as, for example, an intermediate outlet port  266 , as illustrated in FIG. 52. A plate  252  may be provided to facilitate the seal between the thermostatic valve  254  and the intermediate outlet port  266 . A washer  262  may also be provided between the thermostatic valve  254  and the plate  252  to interconnect and seal between the thermostatic valve  254  and plate  252 .  
         [0118]    The biasing member  256  may be disposed between the thermostatic valve  254  and an interface, such as, for example a spring seat  264 , as illustrated in FIG. 52. The spring seat  264  may be utilized to retain the biasing member  256  in its desired orientation by, for example, sliding the biasing member  256  onto the spring seat  264 . The inclusion of the spring seat  264  on the manifold  32  permits the optional use of the thermostatic valve assembly  250  so that the thermostatic valve assembly  250  may be selectively provided in the manifold  32 . Use of the spring seat  264  also permits the thermostatic valve assembly  250  to be easily installed, thereby minimizing installation cost, and disposed entirely within the manifold  32 , thereby further minimizing penetrations into the pipeline and manifold  32 .  
         [0119]    Those of ordinary skill in the art will recognize that many modifications and variations of the present invention may be implemented. The foregoing description and the following claims are intended to cover all such modifications and variations. Furthermore, the materials and processes disclosed are illustrative of the invention but are not exhaustive. Other materials and processes may also be used to utilize the present invention.