Note: Descriptions are shown in the official language in which they were submitted.
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DUAL CATEGORY VENTING SYSTEM
BACKGROUND
[0001] Venting systems for combustive appliances and hearths are
divided into various categories. A category I vent system operates with a
negative draft, and the products of combustion are hot enough to stay well
above dew point. Since a major portion of gas flue products is water vapor,
condensing can occur when the flue products are allowed to cool below
dew point. This can cause corrosion if the wrong materials are used in the
vent system. A category I vent system is typically vented with Type "B" vent
materials.
[0002] A category II vent system also operates with a negative pressure
in the vent, but the temperature of the flue products has cooled to a point
where they may condense into a liquid in the flue. A category II vent
requires vent materials that are resistant to the corrosive effects of flue
gas
condensate.
[0003] Category III and IV vent systems operate with a positive pressure
in the vent system. Positive pressure vents must be fully sealed to prevent
spillage of flue products into an occupied portion of the building. A category
III vent system maintains flue gas temperatures above dew point and
should not condense in the flue. A category IV vent system's flue products
cool below their dew point, therefore it is possible they may condense in the
flue.
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[0004] All vent systems other than category I generally use heat and/or
corrosion resistant materials, which are typically more expensive. Category
IV vent materials are typically fully sealed and constructed from corrosion
resistant materials to withstand the possible corrosive effects from acidic
flue gas condensate.
SUMMARY
[0005] The technology, roughly described, includes a venting installation
for multiple appliances. The installation includes a category I venting pipe
comprising a chase through a structure. The chase includes a first end
positioned adjacent an appliance installation, a second end exiting a
structure and a third end adjacent another appliance. A category II, Ill or IV
vent tube comprising a sealed non-corrosive material is provided in the
chase between the second end and the third end, itself coupled to a high
efficiency category II/111 or IV appliance. The vent tube has a first end and
a
second end and is positioned between the second end of the venting pipe
and the third end of the venting pipe. The vent tube is coupled to a first
appliance and the venting pipe is coupled to a second appliance. A vent
cap is coupled to the second end of the first vent tube and to the second
end of the venting pipe.
[0006] This Summary is provided to introduce a selection of concepts in
a simplified form that are further described below in the Detailed
Description. This Summary is not intended to identify key features or
essential features of the claimed subject matter, nor is it intended to be
used as an aid in determining the scope of the claimed subject matter.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Figure 1 depicts conventional category I appliances connected to
a category I venting system.
[0008] Figure 2 depicts a conventional category II, III or IV appliance and
a category I appliance simultaneously connected to the venting installation
described herein.
[0009] Figure 3A and 3B are exterior views, and Figure 30 a cross-
sectional view, depicting combination venting cap and system in
accordance with the present technology.
[0010] Figure 3D is a perspective view of the venting cap and system of
Figures 3A ¨ 3C.
[0011] Figures 4A ¨ 4B is an exterior view and a cross-sectional view of
a second combination venting cap and system in accordance with the
present technology.
[0012] Figures 5A and 5B are enlarged exterior and cross-sectional
views of the end cap of the first or second embodiment of an adapter shown
in Figure 3.
[0013] Figure 6A and 6B depicts a a second embodiment of a vent cap
suitable for use with the present technology.
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DETAILED DESCRIPTION
[0014] Technology is presented enabling a venting installation for
simultaneous use with an appliance requiring category II, III or IV venting
specifications and an appliance requiring category I venting specification.
The system may utilize existing venting materials installed in a building to
provide clearance and ease in the installation of a venting system suitable
for the appliances. A combination end cap capable of simultaneously
venting both appliances is coupled to a sealed vent tube coupled to the
category II/III/1V device, and a vent pipe surrounding at least a portion of
the
tube and coupled to the category I appliance.
[0015] Figure 1 depicts a category I venting system 100 coupled to a
first category I appliance 190 and a second category I system 192. The
category I system may be comprised of single or double walled vent pipe
comprising one or more pieces 130, 140, 145, 150, 170, 180 in areas where
no combustibles are present. The category I venting system 100 may be
any single or double walled pipe meeting Underwriters Laboratories (UL)
specifications allowing the piping, including portion 145, to be provided
through any combustibles such as ceiling insulation 125, ceiling material
120 or roofing material 110. Double walled portion 145 is typically known
as Type-B vent and is suitable for category I venting purposes. Generally,
venting specifications call for at least one inch of clearance between the
double walled category I material and such combustibles. Procedures for
correctly sizing vents and connectors is published by NFPA in a publication
entitled, NFPA 54: National Fuel Gas Code (NFGC). The standard for
category I gas vents are provided in UL 441, Gas Vents. Standards for
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venting gas appliances are provided in UL 1738, the United Laboratories
Standard for Safety Venting Systems for Gas-Burning Appliances,
Categories II, Ill, and IV-Second Edition; Reprint with Revisions Through
and Including 12/06/2000. The vent system terminates in a vent cap 180 on
the exterior of a building. Generally the vent system 100 and specifically
piece 145 is sized to couple directly to the vent cap 180.
[0016] Other components, such as a storm collar for the exterior of the
building, fire stop at the ceiling, and appliance details, which may be
utilized
with the venting system are not illustrated in the Figures.
[0017] Figure 2 illustrates a first embodiment of the present technology.
In accordance with the technology, a venting installation comprises a
category I venting system 100 used as a chase and an internal venting tube
200 comprising a heat and/or corrosion resistant venting tube 200 having a
diameter smaller than that of the existing material venting components 130,
140, 145, 150, 170 is inserted into the existing system 100. Venting system
100 is coupled to an existing category I device 190 at a first end and
exhaust from the device 192 exits venting system 100 at a second end. A
category II/III/1V device 290 is coupled to venting tube 200 in accordance
with the specifications and requirements of the device near a third end of
system 100, and exhaust from the category II/III/IV device 290 exits through
tube 200.
[0018] A vent cap 300 provides for simultaneous exhaust from both
system 100 and tube 200. The vent cap 300 is detailed further below.
[0019] Optionally, adapters may be used to couple the venting system
100 and tube 200 to the respective appliances 190 and 290. The combined
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venting system comprising venting tube 200 and existing system 100 allows
coupling a category II, Ill or IV appliance as well as a category I appliance
simultaneously through the existing system to the vent cap 300 with relative
ease.
[0020] Internal vent tube 200, in one embodiment, comprises a flexible
venting material comprising a heat and/or corrosive resistant material
suitable for use in category II, Ill or IV systems. Material which is suitable
for use in such systems includes AL29-4C stainless steel and Type 444
Stainless steel. Commercial products suitable for use as vent material 200
include varieties of Type 441, 446, 447, 448, 304, and 316 stainless steeis.
Very high temperature polymeric materials may also be used as the tube
200 in alternative embodiments.
[0021] Typically, a venting system in accordance with the present
technology will be advantageous when replacing an existing category I
appliance with a different type of appliance. During installation, the
existing
vent system is uncoupled from the replaced category I appliance. Likewise,
the existing vent cap 180 is decoupled from the existing vent system. The
venting material 200 is then snaked though the existing system using the
existing system as a chase until the lead end of the material reaches the
second end of the vent system near the vent cap 180.
[0022] The dual exhaust cap 300 is then installed on the end of system
100 at pipe 145a. Cap 300 may be secured to pipe 145a by any number of
suitable fastening means.
[0023] It will be understood that the vent system 100 may be comprised
of various types of materials having different cross sections. In one
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embodiment, the vent pieces have circular or concentric cross-sections. In
an alternative embodiment, the vent pieces have oblong cross sections.
[0024] Vent material 200 is comprised of a vent material having a
diameter or cross-section suitably sized to fit within all components of the
vent system 100. The difference between the cross-sectional size of the
vent system 100 components and that of the vent material 200 can be as
small as minimal as that sufficient to allow the flexible vent pipe to fit
inside
the interior of the exterior vent pipe. Typical type-B vent installations
range
from diameters of 3" to 8". Flexible material suitable for use as vent
material 200 includes FlasNSeal brand flexible super ferritic stainless steel
products from M&G DuraVent Corporation. The use of such material is
merely exemplary, and other corrosion resistant products may likewise be
used.
[0025] Once vent material 200 is positioned in vent system 100, a first
end of the material may be coupled to a category II, Ill or IV appliance 290,
while the second end is coupled to the vent cap 300. In one embodiment,
the vent material 200 may be coupled directly to the apparatus coupling on
the appliance 290 and the vent cap 300. It will be recognized that additional
category II, Ill or IV venting material may be provided at the end of the vent
section.
[0026] It will be recognized that a gap now exists between the exterior of
vent material 200 and the interior wall of the vent system components 130,
140, 150, 170.
[0027] Figures 3 ¨ 5B illustrate different embodiments of a portion of the
venting installation including dual exhaust vent cap 300.
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[0028] Figures 3A
¨ 3D illustrate a portion one embodiment for of a
portion of the installation including elements 145a 130a and cap 300. Cap
300 is detailed below with respect to Figures 4A and 4B. Elements 130a
and 145a may comprise category I venting pipe as discussed above.
Element 130a may include a set off fixture (not shown) for routing the vent
tube 400 through the wye joint element 130a. The set off may comprise a
portion of the wye element 130 or may be a separate fitting that would
ensure open space between tube 200 and elements 130a, 145a and any
other elements of the vent pipe.
[0029] Figures 4A
and 4B illustrate an enlarged view of the end cap 300
and a cross-section of the enlarged view of the end cap. The depiction in
Figure 4A does not illustrate element 145a. Figure 4B is a cross-section
including element 145a. As illustrated therein, cap 300 includes a
cylindrical top surface 310, a top flange 312, perforated sidewall 315
including windows 320, and a bottom flange 322. A bottom cylindrical
surface 335 includes a first aperture 337 surrounded by a flange 325 which
couples to pipe section 145a. Disk 335 supports collar 340 which defines
aperture 337 and serves to allow exhaust from the category I device in the
direction of arrows 400. Disks 335, sidewall 315 and top surface 310 create
an exhaust chamber, with the aperture 337 allowing exhaust from the
category II/III/1V device to exit there through in a plane below a plane
defined by the end of extension 315. Top disk 310 includes an aperture
345 which allows extension 315 there through. Extension 315 is coupled to
pipe 200 so that exhaust from the category II/III/1V device exits from the top
of the extension above disk 310. It should be recognized that while an
extension 315 is illustrated, flexible piping may be extended through
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aperture 345, Extension 315 is coupled to pipe 200, but pipe 200 may be
extended directly through cap 300 and aperture 345 in one embodiment.
While the category I exhaust is provided in the exhaust chamber and the
category II/III/1V above the chamber, this arrangement may be reversed.
[0030] Thus,
exhaust from the category II/III/IV device exits extension
315 in a plane defined by the end of extension 315 above disk 310, and
exhaust from the category I device exits along arrows 400 in a plane below
the end of extension 315, with disk 310 separating the exhausts. Shield
370 is mounted to the top surface 310 and includes disk 372 with a
spherical indentation 374. Shield 370 prevents the ingress of debris and
rain. In addition
shield 370 prevents ice buildup in cold weather
environments.Typically, category II/III/1V devices may have a low
temperature exhaust which has a higher humidity content than category I
devices. This may result in condensation and icing at the exterior of the
cap at lower temperatures. Shield 370 alleviates this issue since, as ice
develops, it will form an icicle at the apex of the indentation which will
break
back down into the category II/III/1V vent.
[0031] Figure 5A
and 5B illustrate the use of a T-coupling 130b with the
venting assembly discussed herein. As illustrated in Figure 5B, a set-off
502 is used to ensure a category I vent pipe connected to junction 510 has
sufficient spacing relative to pipe 200.
[0032] Figures 6A
and 6B illustrate another embodiment of a vent cap
suitable for use with the present technology. The cap 600 comprises a
"high wind" cap suitable for applications where wind speed is a concern.
The high-wind cap 600 includes similar construction to the cap 300 wherein
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the top cap 610 and bottom disk 635 form an exhaust chamber coupled to
the category I pipe by a fitting 625, and the vent pipe 200 couples to
adapter 305 which extends through the chamber to exhaust 315. A shield
structure similar to 370 shown in Figures 4A and 4B may be provided.
