Abstract:
A heater is provided for a waste water system comprising of a heating element encased in a protective pipe. The pipe is closed at one end and attached at the opposite end to an end cap that may be connected by a standard fitting to a sewer installation. The protective pipe is sealed to the end cap and the heating element is removable from within the protective pipe without adversely affecting the integrity of the installation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 62/128,847 filed on Mar. 5, 2015 and the entire contents of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The following relates generally to an apparatus and assembly for heating fluids within a pipe. 
       BACKGROUND OF THE INVENTION 
       [0003]    In cold weather conditions, it is known that the fluid within pipes, such as water mains, drain lines, storm drains and sewers, which does not flow continuously is likely to freeze, thereby causing a blockage of the pipe. One solution is to chemically change the properties of the fluid flowing through the pipe so as to reduce its tendency to freeze in cold conditions. However, this can have an adverse effect on the liquid being transported and it is not usually feasible or economical. 
         [0004]    Another solution is to heat the contents within the pipe so as to counteract the external environmental conditions. Such a solution can include using heat blankets positioned on the outside of the pipe. This is only possible when the pipe is easily accessible. Another option is to use specialty pipes with heated wires permanently located or fixed on the interior or exterior surface of the pipes to increase the temperature of the fluid so as to prevent freezing. This may also not be feasible for existing pipes as it would require replacing the pipes altogether and would be costly for most consumers. Furthermore, as it is difficult to remove the wire from the pipe or to access the wire within the pipe, repair or maintenance of the wire located within the pipe is problematic. Where the wire is located adjacent the surface of the pipe, it may also be vulnerable to normal procedures used for cleaning the pipe in which the wire is installed as threading a cleaning tool through a pipe can often damage the wire rendering it inoperable. 
         [0005]    In another option, customers may seek to heat the pipe locally from the exterior (e.g. by applying a heat source) but localised heating may cause damage to the pipe as the ice thaws. 
         [0006]    In general, many current waste water systems are prone to freezing during winter and require a method to provide a reliable pipe freeze protection. The only current CSA approved solution is to install a heating cable on the outside of the pipe. However, such cables may make only point contact with the outside of the pipe and may cause localised damage to the pipe or may cause localised boiling of liquid in the pipe. As a result, thermal insulation of the pipe is avoided, leading to high energy consumption for the cable. 
         [0007]    It has been proposed to insert a heating cable within a pipe and control the current to the heating cable to prevent freezing. This has proven to be a viable solution in the supply of water to residential units where burial of the supply line is impractical. The cable is surrounded by the water which dissipates heat within the pipe and avoids localised overheating. As such, the exterior of the pipe may be insulated without risking damage to the pipe itself. 
         [0008]    Whilst the above arrangement is satisfactory for water supply, and has CSA approval, it cannot be used in an environment such as sewer lines and septic fields where explosive or inflammable gas may be present, or under conditions where high pressures may be encountered, such as a high pressure water main. 
         [0009]    Therefore, it is an object of the present invention to obviate or to mitigate at least some of the above presented disadvantages. 
       SUMMARY 
       [0010]    In its broad aspect, the present invention provides a heater assembly for a water system consisting of a heating element encased in a protective pipe. The protective pipe is closed at one end and has a retainer adjacent the opposite end that may be connected by a standard fitting of a water line. The protective pipe is sealed to the retainer and the heating element passes through a bore in the retainer so as to be removable from within the protective pipe without adversely affecting the integrity of the installation. 
         [0011]    Preferably, the retainer is a cap removably mounted in the standard fitting to facilitate removal of the heater assembly for routine maintenance of the waste water system. 
         [0012]    Preferably, the heating element is connected to a power supply adjacent to the opposite end of the protective pipe and the connection protected by a seal assembly. 
         [0013]    In a preferred embodiment, the seal assembly includes a heat shrinkable sleeve to cover the connection of the power supply to the heating element and a sleeve to extend over the protective pipe. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: 
           [0015]      FIG. 1  illustrates a heating assembly as installed in a cleanout plug of a sewer or waste drain pipe; 
           [0016]      FIG. 2  is a section on the line II-II of  FIG. 1 ; 
           [0017]      FIG. 3  is an enlarged view of the section shown in  FIG. 2 ; 
           [0018]      FIG. 4  is an exploded view of the components of the heating assembly of  FIG. 1 ; 
           [0019]      FIG. 5  is an enlarged view of a distal end of a component shown in  FIG. 4 ; 
           [0020]      FIG. 6  is a cross section on the line VI-VI of  FIG. 5 ; 
           [0021]      FIG. 7  shows the components of  FIG. 4  during initial assembly; 
           [0022]      FIG. 8-11  show the components of  FIG. 4  during final assembly and sealing of the heating element in the heating assembly; 
           [0023]      FIG. 12  illustrates assembled components of the heating assembly of  FIG. 1 , after assembly 
           [0024]      FIG. 13  illustrates schematically the installation of the heating assembly of  FIG. 1  in a waste water system; 
           [0025]      FIG. 14  illustrates a heating assembly as installed for use in an alternative embodiment of waste water system; 
           [0026]      FIG. 15  illustrates schematically the installation of the heating assembly of  FIG. 14 ; 
           [0027]      FIG. 16  illustrates schematically an alternative installation procedure for the heating assembly of  FIG. 1 ; 
           [0028]      FIG. 17  illustrates schematically a further installation procedure for the heating assembly of  FIG. 1 ; 
           [0029]      FIG. 18  illustrates schematically installation for the heating assembly of  FIG. 1  on a large diameter pipe; 
           [0030]      FIG. 19  illustrates an installation procedure using a saddle for the heating assembly of  FIG. 1 ; 
           [0031]      FIG. 20  illustrates a heating assembly as installed in a sewage basin for use in a pressurized sewage and grey water forced mains in accordance with an alternative embodiment; 
           [0032]      FIG. 21  illustrates the assembled heating assembly of  FIG. 20  shown in isolation; 
           [0033]      FIG. 22  illustrates an installation procedure for assembling the internal components of the heating assembly of  FIG. 20  for installation on a sewage basin; 
           [0034]      FIG. 23  illustrates a schematic view of the components of a coupling assembly for the heating assembly of  FIG. 20 ; 
           [0035]      FIG. 24  is a section on the line XXIV-XXIV of  FIG. 23 . 
           [0036]      FIG. 25  is an enlarged view of a portion of the coupling assembly of  FIG. 24 , and 
           [0037]      FIG. 26  is a view similar to  FIG. 20  of an alternative application. 
       
    
    
     DETAILED DESCRIPTION 
       [0038]    The following is a detailed description of the preferred embodiments. The description should not be considered as limiting the scope of the assembly or apparatus contained herein. 
         [0039]    Referring to  FIGS. 1 and 4 , a heating assembly  100  is installed on a typical residential or commercial waste water system  101 . The waste water system  101  includes a pair of sewage pipes  102  connected by a Y-elbow  103 . The Y-elbow  103  includes a clean out port  104  extending from one leg of the Y-elbow. The port  104  has an internally threaded collar  105  that is provided to receive a fitting, typically an externally threaded plug  1300  as shown in  FIG. 13 . The port  104  is used to connect the heating assembly  100  to the waste water system  101 , as is described below. 
         [0040]    The heating assembly  100  includes an electrical cord  109 , fitted with a plug  112  for connection to a power supply  113 , through a Test/Reset GFCI ( 111 ) located in a controller ( 110 ). The cord  109  is electrically connected to a heating element  120  ( FIG. 2 ) which is preferably a self-regulating heating cable, such as that available from Heat-Line of Canaervon, Ontario, under the trade name HTLN-ATI-5-120R and HTLN-ATI-5-240R. The connection between the cord  109  and heating element  120  is covered with a seal assembly  114  to protect the connection, as will be described in more detail below. The distal end of the heating element  120  is sealed and capped with a protective boot  122  ( FIG. 7 ) about 60 mm in length and a diameter that tapers from 14 mm to 12 mm. 
         [0041]    As seen in  FIG. 2 , the heating element  120  is located within a protective pipe  124  with an internal diameter to accommodate the heating element  120  without undue clearance. The pipe  124  is flexible with sufficient stiffness to allow it to be pushed along the interior of the pipes  102  without buckling. A commercially available HDPE pipe has been found suitable, or alternatively pipe made from ABS, PVC, PEX, or similar materials. In one example a HTLN-ATI-5-120R heating cable from Heat-Line with a cross sectional dimension of 11 mm×6 mm was used in combination with a ½ inch or 12.7 mm ID HDPE (high density polyethylene) pipe. This provided sufficient clearance to allow the heating element to be inserted, but a close enough fit to avoid buckling during the insertion. The protective pipe  124  had sufficient flexibility to accommodate bends in the sewer pipe  102  but sufficient rigidity to allow the pipe  124  to be pushed along the interior of the sewage pipe  102 . The protective pipe  124  may be of any convenient length to suit the particular application, and may extend 200 or 300 feet along the water system when required. 
         [0042]    The heating assembly  100  also includes a retainer configured as a plug  126  which has a boss  128  and a flange  130 . The pipe  124  passes through a bore  125  in the plug  126  with a tight sliding fit to facilitate a seal between the protective pipe and the plug  126 . The diameter of the boss  128  is chosen to correspond with a male connector of a standardized plumbing fitting, nominally a 4 inch diameter male fitting, for conveniently incorporating into an existing system with standard components. The boss  128  is cylindrical to allow a push fit into a plumbing fitting secured to the port  104 . 
         [0043]    The distal end  132  ( FIGS. 5 and 6 ) of the protective pipe  124  is sealed with an end plug  134  which is fusion welded to the wall of the protective pipe  124  for a permanent gas tight seal. The distal end  132  may be tapered or otherwise reduced in diameter, as shown in  FIGS. 5 and 6  to assist in inserting the protective pipe in to the sewer pipe. 
         [0044]    As can best be seen in  FIG. 2 , the heating element  120  is inserted in to the protective pipe  124  so that when assembled, the heating element  120  extends within the protective pipe  124  along a substantial extent of the pipe. The connection of the cable  109  to the heating element  120  is positioned at the outer end of the protective pipe  124 , outboard of the plug  126 . The seal assembly  114 , better seen in  FIG. 3  includes a heat shrinkable sleeve  121  that encompasses the cable  109  and heating element  120  and butts up to the end of the protective pipe  124 . The seal assembly  114  also includes an outer flexible sleeve  150  that is positioned over the end of the pipe  124  and cable  109  to seal the cable  109  to the pipe  124 . 
         [0045]    The plug  126  is connected to the waste water system  101  through a coupling  136 . The coupling  136  is a flexible coupling, such as that available from Fernco, that is compatible with waste water treatment systems. The coupling  136  is dimensioned to receive the male boss  128  as a push fit and a worm screw clamp  138  secures the coupling  136  to the boss. The compression force applied by the worm screw clamp  138  establishes a gas tight seal between the plug  126  and coupling  136  and is also found to be sufficient to establish a gas tight seal between the plug  126  and the protective pipe  124  in the bore  125 . The plug  126  thus acts as a retainer to secure the heating assembly to the waste water system  101 . 
         [0046]    The opposite end of the coupling  136  is connected to a threaded male fitting  140  which has a plain cylindrical boss  142  at one end and a screw thread  144  corresponding to the screw thread in the clean out port  104  at the other. A flange  146  separates the screw thread  144  from the boss  142  and a screw clamp  148  secures the coupling  136  on to the boss  142  of the fitting against the flange  146 . The thread  144  is threaded in to the clean out port  104 . 
         [0047]    As illustrated in  FIG. 13 , to install the heating assembly  100 , the threaded cleanout plug  1300  is removed first from the waste water system  104 . Such ports are required by plumbing codes and are placed at frequent intervals along the length of the system, usually at a bend in the system, to facilitate maintenance. A male fitting  140  is then threaded in to the clean out port  104  with the threads covered with a low friction Teflon tape to ensure a tight seal. A male boss  142  is provided at the opposite end to the threads. 
         [0048]    If necessary, where spacing of the end cap from the Y-elbow  103  is required, the connection to the clean out port  104  may be made with a female threaded coupling, as illustrated in  13 ( b ), and a length of pipe  150  cemented to the female coupling as shown in  FIG. 13( c )  to provide the male boss  142 . 
         [0049]    The coupling  136  is located on the male boss  142 , provided by either the fitting  140  or pipe  150  in the alternative configuration, and secured with the screw clamp  148 . The heating assembly  100  is then inserted in to the waste water system through the port  104 . The plug  126  is then connected to the coupling  136  by feeding the protective pipe  124  containing the heating element through the coupling and in to the sewer pipe  104 . The protective pipe is inserted until the boss  128  is located within the coupling  136  with the flange  130  abutting the coupling  136 . 
         [0050]    The screw clamp  138  then secures the plug  126  to the coupling  136  in a fluid tight seal and also seals the protective pipe  124  to the plug  126 . It will be noted that the push fitting between the boss  128  and the coupling  136  enables the heating assembly to be inserted without rotation relative to the port  104 , and the sliding fit of the protective pipe  124  within the bore  125  enables the position of the plug to be adjusted on the protective pipe  124  during assembly. If required by the particular application, an additional seal, such as a caulk or cement may be provided at the outer end of bore  125 . 
         [0051]    With the protective pipe  124  located within the system  101 , heat may be selectively applied from the power supply to maintain the contents of the sewer pipe above freezing. The protective pipe  124  protects the heating element from external damage, but is sufficiently closely spaced to the heating element to transfer the heat from the element to the interior of the sewer pipe. The protective pipe  124  has sufficient flexibility to follow deviations of the sewer pipe and so may extend a significant distance along the sewer pipe. 
         [0052]    The protective pipe  124  encapsulates the heating element  120  and provides a gas and water impermeable enclosure. This ensures that the heating element  120  is not in contact with the potentially flammable sewer gas, and therefore complies with established safety measures. Similarly, the connection of the end cap  126  to the clean out port  104  using conventional fittings ensures that the integrity of the system  101  is maintained. 
         [0053]    Should it be necessary to remove the heating element  120  for inspection, it is possible to either remove the entire heating assembly  100  and disassemble the heating element, or to simply remove the sleeve  150  and extract the heating element  120  from within the protective pipe  124 . The protective pipe  124  is then left in situ and the integrity of the system  101  maintained whilst the heating element  120  is inspected. 
         [0054]    In the above arrangement, the clean out port  104  is the same nominal diameter as the plug  126 . In some installations, the sewer pipes may be of a different diameter and an alternative configuration of fitting is used. As can be seen in  FIGS. 14 and 15 , where the sewer pipes  104  have a smaller diameter than the plug  126 , a flared coupling  136  is used having the different diameters at opposite ends. Again, as with the embodiment of  FIG. 13 , the male boss  142  may be provided directly on the fitting  140  or may be provided by an extension pipe  150 . 
         [0055]    Similarly, as shown in  FIG. 16 , where the sewer is larger than the plug  126 , the flared coupling  136  is reversed to accommodate the different sizes. As can also be seen in  FIG. 16 , the existing system may be modified by removal of the clean out port  104  and connecting the large end of the flared bushing over the end of the remaining pipe. 
         [0056]    The above description assumes that a Y-elbow with a clean out port is available to facilitate connection of the heating assembly  100 . Where such a port is not available, the waste water system  101  may be readily adapted to permit such use using standard fittings. As shown in  FIG. 17 , a 90° elbow may be removed and replaced with a Y-elbow using the flexible couplers. This permits an installation as shown with respect to  FIG. 1 . 
         [0057]    In another situation, as shown in  FIG. 18 , a Tee is used to connect a short length of pipe with flexible couplings so the protective pipe may be installed. It will be noted that the protective pipe has sufficient flexibility to be inserted in to the pipe  104  and flex through a 90 degree bend to run along the length of the sewer pipe. 
         [0058]    A similar arrangement is possible, as shown in  FIG. 19 , using a 45° saddle connection after a hole is cut in to the sewer pipe  104 . Again the flexibility of the protective pipe allows the pipe and heating element to be inserted at an angle and project along the sewer pipe. 
         [0059]    The above examples illustrate the heating apparatus being used on sewer pipes where the internal pressures are minimal. However, the heating apparatus may be used with advantage in other environments, such as a pressurized water main or the drain line of a sump of a forced flow sewage system as shown in  FIG. 20 . Both of these applications require fittings rated to withstand a pressurized water system. In the embodiment of  FIG. 20 , a sump  200  is used to collect effluent and a pump  202  is activated to discharge the effluent through a waste pipe  204  to the leach field. A Tee piece  206  is provided between the vertical lift and horizontal run of the waste pipe  204  and is used to connect the heating apparatus  100 . The heating apparatus  100  includes a protective pipe  124  encasing the heating element as described above. The pipe  124  is sized to fit within the waste pipe without unduly impeding the flow of water. 
         [0060]    The heating apparatus  100  is secured to the Tee  206  by a step down bushing  208 . A threaded coupling in the form of a stainless steel nipple  210  is threaded in to the bushing  208  and is connected by a support pipe  211  to a strain relief assembly  212 . The support pipe  211  is secured on the coupling  210  by a crimped spirally wound stainless steel band  213  to provide a fluid tight seal. 
         [0061]    The strain relief assembly  212  has a central housing  214 , and a nut  216  that are threaded to one another. A conical clamping ring  218  is located between the housing  214  and nut  216  and bears against a stop collar  219  to grip the outer surface of the support pipe  211  as the housing is tightened. A second nut  220  is threaded on to the opposite side of the housing  214  and similarly has a conical clamping ring  222  to grip the outer surface of the protective pipe  124  and provide a seal around the protective pipe  124 . The clamping ring  222  thus acts as a retainer that is received in the nut  220  and separates the interior and exterior of the water system. 
         [0062]    The radial forces imposed on the protective pipe  124  by the clamping ring  222  may be sufficient to cause deformation or collapse of the wall of the protective pipe  124 . As shown in  FIG. 25 , the protective pipe  124  is reinforced internally by a copper sleeve  224  that extends through the strain relief assembly  212 . The sleeve  224  may be inserted after the heating element is fed in to the protective pipe  124  to ensure that it is not displaced or causes damage to the element  120 . 
         [0063]    The pipe  124  extends beyond the nut  220  and the electrical cord  109  is spliced to the heating element and covered with heat shrink sleeves as described above. The cord  109  is connected to the heating element within the protective pipe  124  so that the connection is protected by the housing and is not subject to tensile loads during operation. The heating element may be easily removed for service if necessary by releasing the heat shrink sleeve and withdrawing the heating element from the protective pipe, thereby allowing the sump pump to continue to function. Similarly, the protective pipe  1124  may be removed by releasing the nut  220  and withdrawing the protective pipe from the waste conduit. 
         [0064]    To permit assembly and insertion of the heating apparatus, the strain relief assembly permits relative rotation of the support pipe  211  and the protective pipe  124 . The nut  216  may be released to allow the pipe  211  to rotate relative to the housing  214  and the protective pipe  124  as the coupling  210  or bushing  208  is fed in to the Tee  206 . The support pipe  211  rotates with the bushing  208  but the strain relief assembly  212  is maintained stationary so that the bushing  208  may be tightened or removed without rotating the protective pipe  124 . 
         [0065]    As noted above, the heating assembly may also be used in pressurized water mains as the protective pipe  124  is formed from a material acceptable for potable water. The installation of the heating assembly is illustrated in  FIG. 26 , from which it will be seen that the coupling  210  is secured by a bushing  208  connected to a Tee in the water main  101 . Again, the heating element is secured by the strain relief assembly  212  as described above and permits the heating element  120  or the protective pipe  124  to be removed as required. 
         [0066]    Accordingly, the systems and methods described herein provide a heating assembly including a heating apparatus that is configured to be received and located on a cleanout plug and within a pipe (e.g. sewer pipe and/or waste drain applications) for providing heat thereto and preventing freezing of the contents within the pipe. The heating element is segregated from the fluid in the pipe, thereby ensuring compliance with the applicable codes, and the element may be easily removed for replacement if necessary without interfering with the operation of the waste water or other fluid transfer systems. 
         [0067]    It will be appreciated that the particular embodiments shown in the figures and described above are for illustrative purposes only and many other variations can be used according to the principles described. Although the above has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art as outlined in the appended claims.