CA2481493C

CA2481493C - Heated plumbing vent

Info

Publication number: CA2481493C
Application number: CA2481493A
Authority: CA
Inventors: Lorne Heise
Original assignee: Heat Line Corp
Current assignee: Heat Line Corp
Priority date: 2004-09-14
Filing date: 2004-09-14
Publication date: 2013-01-29
Anticipated expiration: 2024-09-14
Also published as: CA2481493A1

Abstract

A heated vent is provided which can be coupled to a pipe originating from a plumbing system within a building. A heating cable is wound around an inner cylinder which is wrapped in a conductive foil and enveloped by a larger diameter outer cylinder which is lined with a reflective foil defining a void there between. The cylinders are secured at an upper end by an end cap and at a lower end by a lower end cap and a tether is tautly secured within the inner cylinder by a bridge in an opening of the end cap and a lower disk engaged with the lower end of the inner cylinder to support ice blocks formed therein. The heating cable radiates heat, which is reflected by the reflective foil and absorbed by the conductive foil to prevent ice from forming on the inner surface of the inner cylinder.

Description

4 FIELD OF THE INVENTION:
6 [0001] The present invention relates to a vent used to vent sewer gas and the like.

9 10002] A plumbing system typically includes a water supply system to transfer water from a water main to appliances within a house and a waste water system to carry waste products to a 11 sewer or other disposal system. The waste water system includes a vent pipe to vent gaseous 12 products and water vapour to the outside of a building.. The gaseous products can be sewer 13 gases or other unpleasant fumes that may be noxious or hazardous if allowed to back up within 14 the building.

[0003] It is well known to incorporate a vent pipe into a building by extending a pipe, made 16 of a material such as acrylonitrile butadiene styrene (ABS) or polyvinyl chloride (PVC), from the 17 waste water system to the exterior of the building. In sub-freezing temperatures such as those 18 typically encountered in northern climates, the water vapour that escapes the ventilation pipe 19 may condense when contacting the colder outside air, and begin to freeze against the inner wall of the ventilation pipe eventually completely blocking the vent pipe. With the vent pipe blocked, 21 the gases cannot escape the plumbing system and may back up into the building.

22 [00041 It is therefore an object of the present invention to provide a plumbing vent which 23 obviates or mitigates at least one of the above mentioned disadvantages.

SUMMARY OF THE INVENTION

26 [00051 The present invention provides a vent cap comprising a pair of nested pipes and 27 secured to one another to define a void therebetween. A heating element is situated within the 21317383.1 1 void and is capable of radiating heat for transfer from the outer surface of the inner pipe to the 2 inner surface of the inner pipe to inhibit freezing of the water vapour in the vent pipe.

3 [0006] Preferably, the vent cap has a cord along its axis to retain ice axially and as a further 4 preference a bridge is extended across a lower end of said inner pipe to inhibit downward movement of a mass of ice.

6 [0007] In one embodiment the heating element is an electric heating element.
In another 7 embodiment the heating element is a fluid conduit that passes heated fluid through the void.

8 [0008] To facilitate heat transfer in to the inner pipe, a metal foil is wrapped about the outer 9 surface of the inner pipe within the void and a reflective foil is placed around the inner wall of the outer pipe.

13 [0009] An embodiment of the invention will now be described by way of example only with 14 reference to the accompanying drawings in which:

[0010] Figure 1 is a cross-sectional view of a vent installed on a building.
16 [0011] Figure 2 is a perspective view of the heated vent of Figure 1.

17 [0012] Figure 3 is a cross-sectional view of the heated vent along the line III-III of Figure 2.
18 [0013] Figure 4 is a partial enlarged view of the cap shown in Figure 2.

19 [0014] Figure 5 is an exploded view of Figure 2 illustrating the assembly of the heated vent.
[0015] Figure 6 is a schematic view of alternative heating element controls.

21 [0016] Figure 7 is a schematic view of a hydronic heating system as an alternative to the 22 heating cable shown in Figure 5.

21317383.1 3 [0017] Referring therefore to Figure 1, a building B has a roof R. A vent pipe installation 2 4 of a plumbing system (not shown) protrudes through the roof R of the building B. The vent pipe installation 2 includes a pipe 3 connected to the waste water system and a vent cap assembly 10 6 which extends through the roof R. The vent pipe 3 is typically an ABS pipe, however it may also 7 use other materials.

8 [0018] The details of the vent cap assembly 10 is shown in Figures 2 and 3.
The vent cap 9 assembly 10 has a cylindrical body 11 formed by an outer cylinder 12 and an inner cylinder 13.
The cylinders 12, 13 are generally concentric and dimensioned to provide an annular void 14 11 between them.

12 [0019] One end of the void 14 is sealed by an end cap 16 extending between the outer 13 cylinder 12 and the inner cylinder 13. The end cap 16 has a central opening 18 coinciding with 14 the inner diameter of the inner cylinder 13 with a bridge 20 extending across the opening 18.
[0020] The opposite end of the body 11 is sealed by a lower end cap 22 which extends 16 between the outer cylinder 12 and inner cylinder 13 and projects downwardly from the inner 17 cylinder 13 to provide a skirt 24 for coupling to the vent pipe 3.

18 [0021] An internal tether 28 is attached to the cap 16 at the bridge 20.
The tether 28 extends 19 along the axis of the inner cylinder 13 and is secured to a retaining disc 26 at its lower end. The disc 26 abuts the lower end of the inner cylinder 13 within the skirt 24 and has a central opening 21 30 with a bridge 32 extending across a diameter.

22 [0022] A heating element 40 is located in the void 14. In the embodiment shown in figure 2 23 and 3, the heating element 40 is a self regulating electric heating cable 42, such as that available 24 from Heat-Line Corporation, Canarvon, Ontario under the trademark Paladin I. The heating cable 42 is wrapped spirally about the inner cylinder 13 and exits the void 14 through a strain 21317383.1 1 relief aperture 44 in the lower end cap 22. The cable 42 is connected to a power source, typically 2 an electrical outlet in the building.

3 [0023] A layer of heat conducting foil 36 is wrapped on the outer surface of the inner 4 cylinder 13 from the lower end to the upper end and serves to distribute the heat generated by cable 42 uniformly into the wall of the inner cylinder 13. A liner of reflective foil 48 is also 6 affixed to the interior surface of the outer cylinder 12 to inhibit heat transfer through the outer 7 wall. The void 14 is vented to the atmosphere by a hole 50 in the lower end cap 22 to maintain 8 the void 14 at an equal pressure to the interior of the building B.

9 [0024] An enlarged view of the cap 16 is shown in Figure 4. The cap 14 has an outer sleeve 52, an inner sleeve 54 and a hole 56 for the tether 28 to pass through for fastening. The outer 11 sleeve 52 overlies the wall of the outer cylinder 12 to allow the outer cylinder 12 to be secured to 12 the cap 16 and the inner sleeve 54 is offset from the outer sleeve 52 such that the smaller 13 diameter inner cylinder 13 can also be secured to the cap 16. The sleeves 52, 54 are separated 14 such that the void 14 extends to the upper end of the inner cylinder 13.
The extension of the void 14 allows the heat radiating from the heating cable 42 to rise towards the end cap 16 thereby 16 completely surrounding the inner cylinder 13 and allowing the entire length of the inner cylinder 17 13 to be heated, including the portion secured within the end cap 16.

18 [0025] In an exemplary method for assembling the vent cap assembly 10, the outer cylinder 19 12 is lined with the reflective foil 38 (if applicable) and the inner cylinder 13 is wrapped in the conducting foil 36 (also if applicable). It is next preferable to feed the heating cable 18 through 21 the strain relief aperture 44 in the lower end cap 22 until the majority of the length of the heating 22 cable 42 has been fed.

23 [0026] With the majority of the length of the heating cable 42 fed through the strain relief 24 aperture 44, it is next preferable to wrap the heating cable 42 around the foil-wrapped inner cylinder 13 in a substantially helical pattern to distribute the heat along the entire exposed outer 26 surface of the inner cylinder 13. (e.g. the length of the inner cylinder 13 which is not secured 27 within the end cap 16 nor the lower end cap 22) With this arrangement, the lower end of the 28 inner cylinder 13 can be secured to the lower end cap 22 using a suitable adhesive such as PVC
21317383.1 1 cement. The remaining length of the heating cable 42 is then pulled back through the aperture 44 2 and the strain relief is secured.

3 [0027] The foil-lined outer cylinder 12 can then be slid over the inner cylinder 13 and 4 secured to the larger diameter end of the lower end cap 22 using a suitable adhesive such as PVC
cement. The tether 28 can now be fed through the lower disk 23 and subsequently through the 6 lower end cap 22. The lower end of the tether 28 can then be fastened to the bridge 32 of the 7 lower disk 26 using a suitable fastener 34a. The lower disk 26 can optionally be secured to the 8 lower end of the inner cylinder 13 in which it engages the end of the inner cylinder 13 using a 9 suitable adhesive. The unfastened end of the tether 28 can then be fed through the inner cylinder 13 and subsequently through the hole 56 in the end cap 16. The end cap 16 can then be secured 11 to the upper ends of both the inner cylinder 13 and the outer cylinder 12 using a suitable adhesive 12 such as PVC cement. When secured, the inner sleeve 54 of the end cap 16 will be affixed to an 13 uppermost portion of the inner cylinder 13 and the outer sleeve 52 of the end cap 16 will be 14 affixed to an uppermost portion of the outer cylinder 12 as shown in Figure 4.

[0028] The tether 28 can now be pulled through the hole 56 until taut and suitably trimmed 16 and fastened to the bridge 20 of the end cap 16 using a suitable fastener 34b. Once assembled, 17 the vent cap assembly 10 can be coupled with the existing pipe 3 by securing the pipe 3 to the 18 inner wall of the skirt 24 while inserting the uppermost end of the pipe 3 into the skirt 24. The 19 uppermost end of the pipe 3 is preferably in engagement with the lower disk 26 thereby sealing the pipe 3 to the vent cap assembly 10. The pipe 3 can be secured to the skirt 24 using a suitable 21 adhesive such as a PVC to ABS transition cement or any other adhesive appropriate to the 22 materials used.

23 [0029] It is preferable to have the void 14 completely sealed from the pipe 3 to avoid the 24 heating cable 42 from igniting any potentially volatile gases escaping from the plumbing system.
During assembly, the void 14 may also be filled with an insulating material if desired to provide 26 further insulation surrounding the inner cylinder 13. Any suitable insulating material such as 27 urethane foam can be used. The void 14 would be filled with the insulating material after the 21317383.1 1 inner cylinder 13 has been enveloped by the outer cylinder 12 and the other elements internal to 2 the void 14 (e.g. foils and heating cable) are present within the void 14.

3 [0030] In use therefore, the vent cap assembly 10 is coupled to the pipe 3 as shown in Figure 4 2. When the heating cable 42 has not been energized, the gases originating from the plumbing system and travelling through the pipe 3 will proceed through the vent cap assembly 10 as usual.

6 The openings in both the lower disk 26 and the end cap 16 allow the gases to pass through to the 7 exterior of the building B. If the ambient temperature in the exterior of the building B is 8 subfreezing, the gases (which tend to typically contain moisture) may begin to condense at the 9 interface of the inner cylinder 13 and the exterior of the building B when confronted with colder air. This condensation will then tend to build up as is freezes towards the centre of the opening 11 18 creating an ice blockage.

12 [0031] To remove the blockage, the heat cable 42 is connected to electrical power through 13 the heating element 40. If a self-regulating heating cable is utilised, the drop in ambient 14 temperature will cause the heating effect to increase. Alternatively, the heating cable 42 may incorporate a single pole switch 70 as shown in Figure 6. This single-pole switch 70 allows the 16 heating cable 42 to be turned "on" or "off' manually without using any self-regulating controls.
17 These two arrangements 16, 70 can also be combined to allow the heating cable 42 to be 18 controlled both manually and automatically. The heating effect radiates heat from the heating 19 cable 42. This radiated heat is simultaneously absorbed by the conductive foil 36 and reflected by the reflective foil 38 to distribute the heat in a substantially even manner over the outer 21 surface of the inner cylinder 13. The inner cylinder 13 will transfer this heat due to its 22 conductive properties from its outer surface to its inner surface thereby applying heat to any ice 23 which has formed along its inner surface. It should be noted that the heat is preferably 24 transferred while having the heating cable 42 sealed from the interior of the inner cylinder 13 for safety purposes if the gases are potentially volatile.

26 [0032] The ice will tend to melt inwards towards the tether 28 since it is being heated 27 through the inner cylinder 13 and the tether 28 will support the ice from falling within the inner 28 cylinder 13 and creating unpleasant noise or the ice blockage from being lodged in an elbow of 21317383.1 1 the unheated part of the plumbing system. The lower disk 26 also prevents any large pieces of 2 ice, which may fall through the vent cap assembly 10 from entering the unheated pipe 2. Some 3 of the heat radiated by the heating cable 42 will rise and concentrate within the uppermost 4 portion of the void 14, which lies within the end cap 16. This portion of the void 14 will transfer heat through the inner sleeve 54 and the uppermost portion of the inner cylinder 13 to melt any 6 ice forming the uppermost portion of the inner surface of the inner cylinder 13.

7 [0033] The heated vent 10 may continuously operate to prevent ice blockage by maintaining 8 a desired temperature along the inner surface of the inner pipe. This can be accomplished using 9 a self-regulating heat source and would ultimately prevent any gases from backing up by providing a continuously free passage. Alternatively, to conserve power, the vent cap assembly 11 10 may be de-energized when ice blockage would likely not occur and re-energized in 12 anticipation of cold weather.

13 [0034] Where a self-regulating heat source is used which can vary the heat output based on 14 the ambient temperature, if the ambient temperature rises, the heat output is decreased and conversely if the ambient temperature lowers, the heat output is increased.
This is achieved 16 using a temperature sensor and suitable control electronics, which are well known in the art.

17 [0035] It will be appreciated that the conducting foil 36 and reflective foil 38 are preferable 18 but optional features. It will also be appreciated that the inner cylinder 13, outer cylinder 12, end 19 cap 16 and lower end cap 22 can be constructed using any material and can be of any suitable diameter which will satisfy the relative proportions defined herein.
Preferably, these elements 21 will be constructed using a polycarbonate material, which exhibits good impact resistance in cold 22 weather as well as good thermal conductivity.

23 [0036] It will be appreciated that the heating cable 42 may include any medium capable of 24 conducting heat and an electric heating cable herein described was used for illustrative purposes only.

21317383.1 1 [0037] In an alternative embodiment, a hydronic heating cable 80 shown in Figure 7 2 may be also be used. The hydronic heating cable 80 uses glycol heated by a boiler 82 3 which is fed through the hydronic cable 80, constructed as a small bore tube in a 4 continuous loop.

22222793.1 -8-

Claims

1. A vent cap assembly for connection to a vent pipe of a plumbing system, to vent gas to atmosphere, said vent cap having a body defining a passageway for gas and a heating element to supply heat to at least a portion of said passageway and thereby inhibit freezing of water vapour in said passageway, said heating element being located in a chamber separated by a wall from said passageway, a coupling at one end of said passageway to facilitate connection to said vent pipe, an outlet at the opposite end of said passageway to said coupling to allow egress of gas from said vent pipe to atmosphere and a retainer positioned in said passageway adjacent to said coupling so as to be between said coupling and said portion of said passageway to inhibit egress of a mass of ice from within said passageway to said vent pipe.

2. The vent cap assembly according to claim 1 wherein said retainer includes a tether within said passageway to retain ice with said passageway as it is melted by said heating element.

3. The vent cap assembly according to claim 2 wherein said tether extends axially along said passageway from adjacent to said coupling toward said outlet.

4. The vent cap assembly according to claim 3 wherein said tether is secured to a bridge extending across said passageway.

5. The vent cap assembly according to claim any one of claims 1 to 4 including an insulation layer to inhibit heat transfer from said body.

6. The vent cap assembly according to claim 5 wherein said insulating layer includes a reflective component.

7. The vent cap assembly according to any one of claims 1 to 6 wherein a heat conductive layer extends across at least a part of a surface of said wall to distribute heat from said heating element to said wall.

8. The vent cap assembly according to claim 7 wherein said heating element is supported by said wall and said heat conductive layer is interposed between said element and said wall.

9. The vent cap assembly according to any one of claims 1 to 8 wherein said body is formed by a pair of nested pipes, one of which defines said passageway and the other of which defines said chamber.

10. The vent cap assembly according to claim 9 wherein said passageway is defined by an inner one of said pipes and said chamber is defined by a void between said pipes.

11. The vent cap assembly according to claim 10 wherein said retainer comprises a tether extending axially through the interior of said inner pipe to inhibit downward movement of a mass of ice.

12. The vent cap assembly according to any one of claims 10 or 11 wherein said heating element is wound around said inner pipe within said void.

13. The vent cap assembly according to claim 12 further comprising a layer of conductive material surrounding the outer surface of said inner pipe for dissipating said heat emanating from said heating element over the outer surface of said inner pipe.

14. The vent cap assembly according to claim 13 further comprising a layer of reflective material lining the inner surface of said outer pipe for reflecting said heat radiating from said heating element towards said inner pipe.

15. The vent cap assembly according to any one of claims 10 to 14 wherein said void is filled with an insulating material.

16. The vent cap assembly according to claim 15 wherein said insulating material is a urethane foam.

17. The vent cap assembly according to any one of claims 1 to 16 wherein said retainer comprises a disk positioned at one end of said passageway having a bridge extending across said passageway to restrict said passageway to prevent a mass of ice from entering an adjacent pipe-

18. The vent cap assembly according to claim 17 wherein said retainer further comprises a tether connected to said bridge and retaining ice within said passageway as it is melted by said heating element.