1. Field of the Invention
The present invention is directed to venting of direct vent combustible devices.
2. Description of the Related Art
Direct vent gas stoves and fireplaces are appliances that use a flue to vent combustion waste outside of a dwelling via the most direct route. Venting can occur either vertically, through a wall, generally referred to as a rear vent, or up through the ceiling, generally referred to as a top vent. The key advantage to direct vent appliances is that they are independent of room air and use their own combustion air. Direct vent units are pre-assembled in the factory, are usually made from metal and are made to be easy to install.
Perhaps the biggest advantage of a direct vent fireplace over a gas fireplace using a chimney is that the flue is much smaller in diameter than the average chimney. This means that less heat is lost through the flue than would be through a chimney.
In direct venting, room air is not used for combustion. Rather, air used for combustion is drawn into the combustion chamber by use of a vent which is exposed to the outside ambient air. A direct vent pipe includes two ducts formed by an inner pipe surrounded by a larger diameter outer pipe. A first duct connected to the vent conveys this outside air to the combustion chamber. After combustion, this air and the combustion byproducts are conveyed directly to the vent through a second duct which is isolated from the first duct. The two ducts are typically cylindrical and can be concentric, with the inlet air being conducted to the combustion chamber through an annulus outside the exit air duct and the exit air being conducted to the vent by way of the inner duct, co-linear (or side-by-side), or completely separate ducts.
Vent caps cover the inlet/outlet of the first and second ducts on the outside of a dwelling. One prior art vent typically used two flat plates located a distance away from the outlet of the exit duct. The inner flat plate, which is the plate closest to the exit duct, is impacted by the combustion exhaust products. Because it thereby became heated, a second or outer flat plate of virtually the same dimensions was separated a distance from the first plate to prevent burns. A third plate with a centre hole was provided between the first plate and the outlet of the exhaust duct. Another prior art cap is shown in U.S. Pat. No. 6,289,886. The cap shown therein utilizes a curved outer cover with an accurately shaped inner surface to dissipate exhaust gases. No “second plate” separates this accurately shaped surface from impact gasses.
Winds and drafts around the vent cap can also affect the backpressure in the duct. If there is backpressure present in the exit duct, the draw of inlet air will be reduced which will decrease combustion efficiency and can lead, in poorly designed systems, to extinguishing the combustion flame.
The present invention, roughly described, pertains to a vent cap for a direct vent system. The cap may include a base plate and a semicircular outer housing secured to the base plate. A divider is coupled within the outer housing, with the divider forming in exhaust region and an inlet region. A heat shield is positioned within the semicircular outer housing in the outlet region. A direct vent pipe coupling is provided in the base plate and includes a first pipe having an outlet coupled to the divider.
In one embodiment, the heat shield has an arcuate shape generally matching a cross-sectional shape of the semicircular outer housing.
In another embodiment, a vent cap for a direct vent system includes a backing plate, a first semicircular outer housing secured to a first portion of the backing plate and a second semicircular outer housing secured to a second portion of the backing plate. A divider is coupled within the first outer housing, with the divider forming in exhaust region and an inlet region. A heat shield is positioned within the first semicircular outer housing in the outlet region. A direct vent pipe coupling is positioned in the second portion of the backing plate. A vent pipe stem is provided in the first and second housings and connecting one duct of the pipe coupling to the divider.
Another embodiment of the vent cap comprises a backing plate, a first arcuate outer housing secured to a first portion of the backing plate, a second arcuate outer housing secured to a second portion of the backing plate and a third semicircular outer housing secured to a third portion of the backing plate, between the first and second portions. A divider is coupled within the third outer housing, the divider forming in exhaust region and an inlet region. A heat shield is positioned within the third semicircular outer housing in the outlet region, and a direct vent pipe coupling is provided in the backing plate.
These and other objects and advantages of the present invention will appear more clearly from the following description in which the preferred embodiment of the invention has been set forth in conjunction with the drawings.
A unique vent cap for use in conjunction with a direct vent appliance and venting system provides a number of advantages over conventional vent caps. Numerous embodiments of the vent cap of the present invention are disclosed. It will be recognized that various combinations of components of each embodiment may be substituted for components disclosed with other embodiments, providing numerous variations of the cap, all of which are intended to be within the scope of the attached claims.
With reference to
Backing plate 110 has a top-side 102, a left-side 106, a right-side 104, and a bottom-side 108. Where cap 100 is designed for use with 4×6⅝-⅝″ pipe, each side 102, 104, 106, 108 may have a length of about 9″. It will be recognized that any number of suitable sizes may be used with the invention.
An outer cover 140 having a semi-circular assembled cross-section (when viewed from the top or bottom as illustrated in
Divider 160 has a shield 150 coupled thereto (by welding, spot welding, bolting, riveting, or other suitable means) which includes a cut-out 162 sufficient to allow mating with the inner mating sleeve 170. Shield 150 has an arcuate shape best depicted in phantom in
A direct vent pipe coupling is formed by an outer mating sleeve 180 and inner mating sleeve 170, which secure the two duct, direct vent pipe (not shown) to the vent cap 100. Outer sleeve 180 may be welded or otherwise secured to back plate 110. Inner sleeve 170 is secured in divider 160 and is positioned within outer sleeve 180. Alternatively, spacers may be provided between inner sleeve 170 and outer sleeve 180 to secure the sleeves to each other. The outer mounting sleeve 180 is designed to couple to a direct vent pipe in a well-known manner. For example, the outer sleeve may include ridges to allow the pipe coupling to engage a twist lock coupling such as that commercially available from Simpson Dura-Vent Corporation, which is a bayonet-style lock allowing one end of the pipe to be inserted into the outer pipe 180 and twisted into place to secure it therein.
The inner sleeve 170 and outer sleeve 180 are sized relative to the size of the connection to be made. For example, in one embodiment where the cap is to be used with 4×6⅝″ pipe the inner sleeve 170 will have a diameter of about 4″ and the cut-out 162 a diameter of 4 1/16 inches. Where the inner sleeve is to be press fit into the cut-out 162, the cut-out may be made to a diameter of about 3 11/32,″ slots formed in the cut out and the interior sides bent to form flanges surrounding the sleeve 170 when inserted into the bore 162. Likewise, where the outer liner 180 has a 6⅝″ inch diameter, the cut out will have a 6 23/32″ diameter. If the outer liner 180 is designed to be press-fit into backing plate 110, bore 112 may be cut to a diameter of 5 11/32″ and the interior sides bent back so that the sleeve 180 is secured therein.
As illustrated in
As illustrated in
In cap 100, the inner sleeve 170 and outer sleeve 180 are mounted in the approximate center of backing plate 110. Likewise, the sleeves 170 and 180 are located at the approximate center of the inlet and exhaust regions of the cap 100 (as viewed in
Vent cap 100 provides a number of advantages over the prior art. In particular, the external semi-circular housing 140 of the vent cap is shielded from excessive heat by use of the accurate interior shield 150. Likewise, the use of divider 160 inhibits intermixing of the gases in the exhaust area exiting from regions 123 and 133, and input air entering in region 122 and 132. Because of the outward circular shape of the outer housing 140, the vent cap is less resistant to adverse effects from wind or less likely to cause injuries to individuals who may encounter the vent cap 100 by accident. The ambient temperature of the outer cover 140 is reduced due to the presence of shield 150 therein. Likewise, the absence of rough edge at the exterior cap 140 prevents injury to individuals who may strike the vent cap inadvertently, reducing the risk of receiving serious injury.
In a system where a so called 4×6⅝″ direct vent pipe is used to vent the appliance, the area provided by the interior pipe is about 12.56 square inches, the outer pipe about 21.91 square inches, and the area between the top and bottom openings in the cap about 30.94 square inches.
In the embodiment of
In yet another embodiment of the invention, the outer covers may be labeled with the word “hot” embossed into the outer metal cover to warn people close to the vent of the heat danger associated therewith.
Vent 200 includes an upper portion 215 which resembles the first embodiment of the vent pipe 100 of the present invention, and a lower portion 225. As illustrated in
Backing plate 210 has a generally rectangular shape defined by shorter length top side 202 and bottom side 208, and longer left and right sides 206, 204. Where cap 200 is designed for use with 3×4⅝″ direct vent pipe, backing plate 210 may have sides 202, 208 with a length of about 8 inches, and sides 206, 208 with a length of 24.86″. Like backing plate 110, rectangular side flanges may be formed to define each edge 202, 204, 206, 208 and serve as support for mounting covers 240, 228 thereon. A cutout 212 is provided in backing plate 210 to which outer mounting ring 280 is secured by welding or other suitable means. Outer covers 240 and 228 are secured to backing plate 210 by welding, bolting, riveting, or other suitable means, and serve as structural support for various components of the cover 200, as described below. In the aforementioned 3×4⅝″ pipe embodiment, cap 240 has edges 240a,b having a length of about 10″ inches, while cover 228 has edges 228a,b having a length of about 12.85″.
Upper portion 215 of vent cap 200 includes an outer semi-circular housing 240, interior shield 250, and divider 260 which function in a manner similar to those elements 140, 150 and 160 in the embodiment of
Inner pipe 272 transports exhaust gases to the exhaust region formed between shield 250 and divider 260. In the embodiment shown in
Again with respect to vent cap 200, the inner sleeve 270 and outer sleeve 280 are sized relative to the size of the direct vent pipe connection to be made. Likewise, the bore in shield 160 may be sized relative to the inner pipe specified above with respect to liner 170 and divider 160.
In this embodiment, slots are used to cover the intake and exhaust areas, rather than the large holes (such as, for example, holes 222, 223 illustrated above). In cover 320, a plurality of slots 322a,b, 324a,b, 326a,b, 328a,b, 330a,b, 332a,b, 334a,b, and 336a,b can take the place of holes 222, 223 or 232, 233. In
As illustrated in
The vent cover 420 includes a first plurality of slots 422a, 422b, each slot having an angled flange 423a, 423b respectively which, as illustrated in
This latter embodiment is shown in another alternative embodiment—vent cap 500—shown in
A lower vent cap 530 has a configuration equivalent to vent cover 420 with a plurality of forward facing slots 526 (equivalent to slots 424a, 424b) and rearward facing slots 528 (equivalent to slots 422a, 422b).
Vent cap 500 also incorporates the use of a rounded cross-section, standard direct vent coupling pipe 574 in place of the oblong pipe 272 of
A further alternative of the present invention is shown in
Yet another configuration of the vent cap of the present invention is shown in
A direct vent pipe coupling comprises an outer mating sleeve 180 and inner mating sleeve 670 secure the two duct direct vent pipe (not shown) to the vent cap 600. Outer sleeve 680 may be welded or otherwise secured to back plate 610. In another alternative, inner sleeve 670 is positioned within outer sleeve 180 and is secured to divider 660. The outer mounting sleeve is designed to couple to a direct vent pipe in a well-known manner.
The inner liner and outer liner are sized relative to the size of the connection to be made. As illustrated in
Additional intake side vents 624, 626 allow additional inflow air to be received in the intake region.
The foregoing detailed description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. The described embodiments were chosen in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
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Number | Date | Country | |
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20060243268 A1 | Nov 2006 | US |