Patent Publication Number: US-2007095931-A1

Title: Hydronic heating system, hanger for tubing and method of using same to install the hydronic heating system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This is the first application filed for the present invention.  
     MICROFICHE APPENDIX  
      Not Applicable.  
     TECHNICAL FIELD  
      The present invention relates generally to radiant heating systems and, in particular, to hangers for installing tubing in a radiant heating system.  
     BACKGROUND OF THE INVENTION  
      Radiant heating systems for living and/or working spaces are widely known. One popular type of radiant heating system for these applications is the hydronic heating system wherein a heated fluid such as water is pumped through an endless tubing loop installed under a floor (“RFH” or Radiant Floor Heating) or inside a wall (“RWH” or Radiant Wall Heating). Heat is supplied to the living area or workspace from heated fluid circulated through the endless loop which heats the floor or wall via natural heat transfer mechanisms, i.e. radiation, convection and conduction. The fluid is typically heated by a boiler which burns a carbonaceous fuel such as natural gas or fuel oil or, alternatively, by a gas or electrical heated water heater, or the like.  
      Traditionally, hydronic heating coils have been installed between floor joists or wall studs with at least one loop between each pair of adjacent joists or studs. Furthermore, the endless loop has traditionally been supported in close contact with the floor or wall surface and heat conductive plates have been used to enhance the radiation of heat from the endless loop to the undersurface of the floor.  
      Prior art radiant heating systems suffer from a number of disadvantages. First, the radiant plates which support the heating tubes are secured directly to the floor or wall surface. This promotes “hot spots” on the floor or wall. Heating fluid temperatures must therefore be controlled in order to prevent hot spots which could prove injurious or discomforting to occupants of the heated space. Second, plastic tubing used in hydronic heating system is vulnerable to puncture by fasteners driven through the flooring or the wall structure by persons who are not aware of the hazard. Such accidental damage to the heating system can cause water damage and potentially cause damage to the fluid distribution pump and/or the boiler used for heating the fluid. Third, at least one loop is required in each inter-joist space in order to lay out the endless heating loop efficiently as well as to provide adequate radiant heat in most climates. Fourth, as noted above most boilers operate at temperatures which exceed the desired temperature of a floor surface. It is therefore necessary to provide some mechanical arrangement to prevent fluid heated by the boiler from circulating in an undiluted condition through the hydronic heating system. Expensive flow control components which must be installed by skilled workmen are therefore required in the heating system. This contributes to the cost of installation and maintenance of the system.  
      These problems were addressed by the hydronic heating system described in Applicant&#39;s U.S. Pat. No. 5,542,603 (MacDuff) which issued Aug. 6, 1996. This hydronic heating system includes a conduit for circulating heated fluid beneath a floor. The conduit is suspended a predetermined distance beneath the floor, which provides more uniform heat transfer, eliminating unwanted hot spots. The hydronic heating system is installed so that the conduit runs transverse to the floor joists, i.e. the conduit passes through holes bored in the joists.  
      Accordingly, it is desirable to provide an improved hydronic heating system that facilitates installation by permitting the fluid conduit to be run between, and generally parallel to, the floor joists to facilitate installation.  
     SUMMARY OF THE INVENTION  
      It is therefore an object of the invention to provide a hydronic heating system that is rapidly and easily installed.  
      The invention therefore provides a hydronic heating system for radiant floor heating, comprising a length of tubing defining a conduit within which a heated fluid can be circulated; and a plurality of hangers that suspend the tubing a predetermined distance beneath the floor, each hanger comprising: a stem having a top end that can be secured to the underside of the floor; and a helical hook at a bottom end of the stem for supporting the tubing, the helical hook having a free end that is spaced away from the stem a distance that is about equal to an outer diameter of the tubing, the helical hook forming an arc with respect to the stem that does not exceed 270° to permit the hook to be slid over a side of the tubing and rotated 90° to lock the tubing within the hook when the hanger is secured to the underside of the floor.  
      The invention further provides a method of installing a hydronic heating system, the method comprising: extending a tubing beneath a floor to be heated; sliding a helical hook at a bottom end of a hanger over the tubing, the helical hook having a free end that is spaced away from a stem of the hanger by a distance that is about equal to an outer diameter of the tubing, the helical hook forming an arc with respect to the stem that does not exceed 270° to permit the hook to be slid over a side of the tubing and rotated 90° to lock the tubing within the hook when the hanger is secured to the underside of the floor; and, sliding the hangers over the tubing at predetermined intervals and securing the respective hangers to an underside of the floor to suspend the tubing a predetermined distance below the underside of the floor.  
      The invention further provides a hanger for suspending a tubing for circulating a heated fluid in a hydronic heating system. The hanger comprises a stem having a top end securable to an underside of a floor; and a helical hook at a bottom end of the stem, the hook having a free end that is spaced from the stem by a distance that is about equal to an outer diameter of the tubing, the helix forming an arc with respect to the stem that does not exceed 270° to permit the hook to be slid over a side of the tubing and rotated 90° to lock the tubing within the hook when the hanger is secured to the underside of the floor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:  
       FIG. 1  is a schematic plan view of a hydronic heating system in accordance with an embodiment of the invention;  
       FIG. 2  is a front elevational view of a hanger for use in the hydronic heating in accordance with the invention;  
       FIG. 3  is a side view of the hanger shown in  FIG. 2 , with a fastener for fastening the hanger to an underside of a floor;  
       FIG. 4  is a front view of the hanger shown in  FIG. 2 ;  
       FIG. 5  is a top plan view of the hanger shown in  FIG. 2 ;  
       FIG. 6  is an isometric view of the hanger shown in  FIG. 2 , preassembled with a fastener; and  
       FIG. 7  is a perspective view of a section of tubing supported by the hanger shown in  FIGS. 2-6 . 
    
    
      It should be noted that throughout the appended drawings, like features are identified by like reference numerals.  
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      The invention provides a hydronic heating system and a hanger that facilitates installation of fluid distribution tubing for the hydronic heating system.  
       FIG. 1  is a schematic plan view of a hydronic heating system, generally designated by reference numeral  10 , in accordance with an embodiment of the invention. As shown in  FIG. 1 , the hydronic heating system  10  transfers radiant heat from a fluid heated by a boiler  12  or other heater for heating the fluid, e.g., water. A pump  14 , can be located upstream or downstream of the boiler  12 , although, as is known in the art, the system will perform more efficiently if the pump is located upstream of the boiler, as shown in  FIG. 1 . The boiler  12  and the pump  14  can be separate units, as shown, or different subcomponents of the same unit.  
      As shown in  FIG. 1 , the pump  14  circulates the heated fluid through a tubing that defines a conduit  16 . In one embodiment, the conduit is made of a composite tubing which includes plastic and aluminum components to prevent the intrusion of atmospheric oxygen into the heating fluid, which can corrode boiler parts and even attack the plastic tubing at elevated temperatures. This type of composite tubing is well known and commercially available from a number of suppliers.  
      As shown in  FIG. 1 , the hydronic heating system may optionally include a return manifold  18  and a distribution manifold  20 . The return manifold  18  has a plurality of inlet ports  22  and the distribution manifold  20  has a plurality of outlet ports  24  for connecting to other conduits  26 ,  28  that convey the heated fluid to other heating zones. These manifolds therefore permit several heating circuits (or “heating loops”) to be connected to a single boiler loop.  
      The hydronic heating system  10  typically includes a zone valve  30  for regulating the fluid flow through the conduit  16 . The zone valve  30  is controlled by a thermostat (not shown), which opens the zone valve  30  when the thermostat demands heat and closes the zone valve  30  when heat is no longer required. Typically, the thermostat also controls the boiler  12  and pump  14 .  
      As shown in  FIG. 1 , the conduit  16  loops back and forth under a floor  42  of a zone  40  and runs between and generally parallel to the floor joists  44 . In other words, the conduit  16  passes through the “inter-joist spaces” beneath the floor  42 . As shown, the tubing is pulled through holes  46  drilled in ends the joists to enable the tubing to be extended into an adjacent inter-joist space.  
      A plurality of heat-radiating fins  50  which promote heat transfer from the tubing/conduit  16 , are connected to the tubing  16  at predefined intervals, as described in Applicant&#39;s U.S. Pat. No. 5,542,603 (MacDuff) entitled HYDRONIC HEATING SYSTEM which is hereby incorporated by reference.  
      As shown in  FIG. 1 , the hydronic heating system  10  further includes a plurality of hangers  100  in accordance with the invention. As will be described in greater detail below, the hangers  100  suspend the tubing (conduit)  16  a predetermined distance beneath an underside of the floor  42  in order to provide uniform heat transfer to the floor and to thus preclude the creation of any unwanted hot spots on the floor. It should be expressly understood that the distribution and spacing of the hangers  100  or the heat radiating fins  50  shown schematically in  FIG. 1  are not intended to reflect a distribution and spacing that would actually be used to suspend the tubing.  
      It should also be expressly understood that although the invention is illustrated with reference to a floor supported by floor joists through which holes may be bored, the invention is equally adapted to be used with floors constructed with open or “space joist” systems, well known in the art, stressed-skin panels, reinforced concrete, or any other flooring system that presents a relatively flat floor underside into which fasteners can be driven.  
       FIGS. 2-5  illustrate the hanger  100  in accordance with an embodiment of the invention. The hanger  100  includes a stem  102  having a top end  104  connectable to an underside  41  of a floor  42 , e.g. a sub floor. In one embodiment, the top end  104  includes an upper loop  106  formed integrally with the stem  102 . The upper loop  106  defines an passage  108  (shown in the top view of  FIG. 5 ) through which a fastener  110  (shown in  FIG. 3 ) can be inserted for securing the hanger  100  to the underside  41  of the floor  42 . In one embodiment, the fastener  110  is a threaded fastener having a head  112  substantially larger than the passage  108  defined by the upper loop  106  and threads  114 .  
      The hanger  100  further includes a helical hook  120  at a bottom end  122  of the stem  102 . The hook  120  has a free end  124  that is spaced apart from the stem  102  by a distance  126  that is about equal to an outer diameter of the tubing  16 . The helical hook spirals away from the stem  102  and forms an arc with respect to the stem that does not exceed 270° (see  FIG. 2 ) to provide a substantially circular seat  128  for supporting the tubing  16 . The geometry of the helical hook  120  facilitates the sliding of the helical hook  120  over the tubing  16  and ensures that the retention of the tubing  16  by the hook when the hanger  100  is fastened to the underside  41  of the floor  42 .  
      In one embodiment, the helical hook  120  is integrally formed with the stem  102 . In one embodiment, the stem  102  (including the upper loop  106 ) and the hook  120  are integrally formed from a single piece of metal wire, stainless steel for example. The hanger  100  can be constructed to accommodate any size of tubing. The length of the stem  102  positions the tubing a desired distance beneath the floor, such as, for example, three inches.  
      As illustrated in  FIG. 6 , the hanger can also be preassembled with a fastener  150  having a narrow neck region  152 , in accordance with another embodiment of the invention. The narrow neck region  152  is rotatably restrained within the passage  108  defined by the upper loop  106 . In other words, the fastener  150  is rotatably restrained within the loop  106  to further facilitate the task of hanging the tubing  16  to provide a hydronic heating system.  
       FIG. 7  illustrates a section of tubing  16  supported by the helical hook  120  of the hanger  100 . The tubing is not tightly or snugly gripped by the hanger  100 . Rather, there is enough play to permit the tubing to slide longitudinally through the hanger  100 .  
      The hydronic heating system  10  can be installed by extending or “pulling” a tubing  16  beneath a floor  42  to be heated. The tubing  16  is positioned between and generally parallel to floor joists  44  as was shown in  FIG. 1 . Holes  46  are drilled in the ends of the joists  44  to enable the tubing  16  to be looped in a continuous circuit beneath the floor  42 . The tubing  16  is then suspended or hung using the hangers  100 , which are secured by fastening each one to an underside of the floor using, for example, a threaded fastener  110 . The suspension of the tubing  16  is rapidly accomplished and the installation of the hydronic heating system  10  is greatly facilitated. It should be understood that although the hydronic heating system is shown installed between joists in  FIG. 1 , if an open joist system or a stressed skin panel flooring system is used, the hydronic heating system in accordance with the invention can be installed transversely to joists or beams supporting the floor.  
      During installation, each successive hanger  100  is slipped over the tubing  16  by passing the tubing through the gap  126  and rotating the hanger  100  about 90° before fastening the hanger  100  to the underside  41  of the floor  42  using a threaded fastener  110 , for example. In one embodiment, the hangers  100  are secured to the underside of the floor  42  midway between adjacent joists  44  to ensure uniform heat transfer to the floor  42 .  
      Once all of the tubing  16  is hung for the zone  40 , the tubing  16  is connected to the boiler  12  and pump  14 , or, if there are other zones, to the return and distribution manifolds  18 ,  20 , as described earlier.  
      The heat-radiating fins  50  are attached to the tubing  16  in order to promote heat transfer from the tubing  16  to the floor  42 . The heat-radiating fins  50  may be attached to the tubing  16  after the tubing is threaded through the respective joists and either before or after the hangers  100  are installed to support the tubing  16 .  
      The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.