Note: Descriptions are shown in the official language in which they were submitted.
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Title: Flapper Valve Adaptor for a Roof Vent and Method of Installing
the Same
FIELD OF THE INVENTION
This invention relates generally to the field of roof vents, and more
particularly to the type of roof vents that may be used to provide
ventilation from a building enclosure. Most particularly this invention
relates to the type of roof vents that may require a flapper valve, such as
is common with forced air venting from, for example, bathroom fans,
range fans and the like.
BACKGROUND OF THE INVENTION
Exhaust fans are often provided to suck moist air from bathrooms,
smoke and steam from kitchens, and for other reasons. They are
particularly useful in removing moist air from bathrooms where for
example showering may take place which can create a great deal of
steam. The removal of such moist air will limit the formation of mould or
the like which can be a cleanliness and safety issue. Usually such
bathroom fans are activated by a separate switch and can be turned on or
off at will. Alternatively they may be automatically operated when there is
enough moisture in the air or the bathroom is otherwise occupied. When
activated the fan will suck air from the bathroom, usually at a ceiling level
and then exhaust it to the outside through a dedicated exhaust duct. The
fan creates a positive air flow that pushes the air out through the duct and
then typically through a flapper valve, before it reaches the outside. The
flapper valve typically opens by reason of the positive air pressure and
then closes due to gravity.
Various types of vent structures exist to house the flapper valve at
the discharge end of the duct. In general such vent structures typically
include a body on the outside which covers the duct opening and prevents
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weather from entering backwardly through the duct. As well, typically the
vent body includes a form of grill or the like to let air pass out while at
the
same time to keep out pests such as birds, bugs and rodents or the like
from entering the building through the duct. As well, as noted above, they
typically include a flapper valve to prevent the loss of air (and thus
energy) out of the discharge end of the duct when the fan is not operating.
Lastly, they typically include some form of collar to anchor the duct in
place to the body of the vent.
Although many prior designs of specialized vent bodies have been
proposed in the past, in some cases roofers will cover the duct discharge
end with a conventional passive roof vent. While this provides some
protection for the discharge end of the duct it is generally not sufficient,
in
that there may be no provision of a flapper valve. Without a flapper valve
this can lead to drafts in the bathroom and a loss of energy. The flapper
doesn't allow the moist air to freeze. In a prior patent to Ward (U.S.
Patent No. 8,205,401), an attempt is made to provide a flapper adaptor so
that a conventional passive roof vent can be adapted to perform as an
end cover for a bathroom or forced air duct. In Ward there is provided a
device which includes a separate flapper adaptor unit which defines a
discharge chimney that extends up above the roof surface. A flapper
valve hinged at an angle and attached at one end is provided on the top
of the chimney. The flapper adaptor is provided with upwardly reaching
fingers to allow it to be placed inside of the vent opening of the vent body
and to grab the top edge of the same to keep it in place. Below a
separate collar adaptor, with various collar diameters for attaching to
different sizes of ducts, is provided. The separate collar adaptor, the
flapper adaptor and the body of the vent are then combined together to
form a complete unit.
While providing a flapper valve option for the specific roof vent
design shown there are certain problems associated with this prior design.
The design involves three separate components each of which must be
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positioned correctly to ensure the combination functions as required. The
use of separate components leads to the risks of installer error and leaks.
As well the flapper adaptor includes a raised collar which has an angled
top on which the flapper valve sits. To ensure proper functioning of the
flapper valve the valve must be oriented correctly, relative to the roof
incline, to prevent the flapper valve from being too hard to lift. As well the
flapper valve stands proud of the roof deck meaning that the body of the
vent must be large enough to accommodate the range of travel of the
flapper valve when it opens and closes and the adaptor fingers will only
latch onto a vent having a vent opening as shown in the drawings. Thus
this prior adaptor combination is limited to being used with a roof vent the
same as or substantially the same as what is shown.
Other types of flapper valves provided in the prior art include:
United States Patent No. 4,144,802
United States Patent No. 4,432,273
United States Patent No. 4,593,504
United States Patent No. 5,662,522
United States Patent No. 5,749,780
Canadian Patent No. 2,696,466
What is desired is a simple and reliable universal adaptor that can
be used in association with many different types and styles of roof vent
bodies. A universal adaptor is desirable as opposed to one which can
only be used in association with one specific roof vent body as taught in
the prior art. Preferably such
a universal device would be simple to
minimize the risk of incorrect installation and in-expensive to make and
use. Preferably such a product can be installed from either side of the
roof sheathing. Such a design is also preferably reliable. Most preferable
such a device would be made from a durable molded plastic and would be
compatible with a wide range of vent bodies.
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SUMMARY OF THE INVENTION
The present invention is directed to a form of universal adaptor
which may be used in association with many different vent body designs.
Essentially the present invention may provide a reliable flapper valve
element that can be mounted to the discharge end of an adaptive collar to
connect to a forced air duct such as one coming from a bathroom fan.
The present invention may present a low profile design, by mounting the
flapper valve within the well formed by the adaptive collar. Preferably the
design includes control over the extent of rotation of the flapper valve,
through for example the use of limit stops. It may only require a low
activation pressure for opening and closing the valve as compared to
some of the prior art. In this way the present invention provides for an
easy to use adaptor to mount on the end of a forced air discharge duct
which is also efficient at permitting the desired discharge of exhaust air.
The present invention may be molded from highly durable plastic and is
easily retrofit to an existing installation and can be used with a wide
variety of conventional roof vent styles and forms.
According to one embodiment the present invention provides a
flapper valve adaptor for a passive roof vent, the flapper valve adaptor
comprising:
a base securable to a sloped roof deck and having an integrally
moulded stepped collar extending from the base on one side for
connecting to different air duct sizes and to define a discharge end for an
air flow passageway,
a central well defined by the collar adjacent to and below the base
and being open towards the other side of the base from said one side;
a hinge pin retained in the open central well below said base to
define a central pivot axis within said central well and oriented to be
generally aligned with said roof deck slope when base is secured to said
sloped roof deck;
a pair of opposed flapper valves hinged to said hinge pin and
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pivoting about a closed position in which the flapper valves is biased by
gravity to close the air flow passageway and an open position in which the
flapper valves are opened by air pressure from within said air flow
passageway;
wherein said flapper valves, remain partially within said well when
said flapper valves are fully open.
According to another aspect the present invention provides a
method of installing a flapper valve assembly together with a passive
exterior roof vent in a roof at a location having a generally planar surface
which slopes down from a roof peak, said method comprising the steps of:
trimming a stepped collar having an integral base to match the
diameter of an air duct to be vented;
securing the stepped collar to the air duct at one end and to a roof
deck at the other end at said integral base;
securing a hinge pin in a central well of said stepped collar in an
orientation that is generally perpendicular to a roof peak and generally
below the planar roof surface;
pivotally securing flapper elements to said hinge pin; and
mounting said exterior roof vent over said flapper valve adaptor.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will now be made by way of example only to preferred
embodiments of the invention by reference to the following drawing in
which:
Figure 1 is an exploded view of the components of an adaptor
collar assembly according to one embodiment of the present invention;
Figure 2 is a side view of the components of Figure 1 assembled
together; and
Figure 3 is a cross-sectional end view of the components of Figure
2.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figure 1 shows an adaptor collar according to the present
invention. As shown the adaptor collar has an attachment base 10 from
which extend a number of different sized collars 12, 14, and 16. Each
collar section is comprised of a duct attachment portion 18, 20 and 22
separated by horizontal steps 24 and 26. The smallest diameter
connector 12 is the furthest from the base 10 and each successive
connector section 14, 16 is of a larger diameter. Three sizes are believed
to cover the usual range of ducts that might be used in typical duct work in
a building. It will be understood that the collar sections that are too small
to match the air duct which attaches to the adaptor may be trimmed off
before the air duct connection is made.
It will also be understood that the duct collar sections 12, 14, and
16 are integrally moulded to each other and the last or largest one 16 is
integrally moulded to the base 10. In this way once the duct is attached to
the appropriate sized collar 12, 14 or 16, the adaptor collar forms a direct
airway connection to the outside. The base 10 can be mounted on the
inside or outside of a building enclosure such as by being incorporated
into a shingle roof for example, with the collar extending downwardly
through an opening in the roof and down towards a connecting air duct so
that a connection can be made.
As shown each collar consists of a generally vertical sidewall
section 18, 20 and 22 separated by generally horizontal sections or steps
24 and 26. The generally vertical sidewall sections 18, 20 and 22 may be
tapered to make it easier to secure the duct over the collar sections. In
this case the taper may extend from a narrower diameter further from the
base 10 to a larger diameter closer to the base 10. The horizontal
sections simply transition the collar diameter from one size to the next.
The steps 24, 26 could be placed at an angle, rather than being at 90
degrees to the collar section, but the 90 degree configuration works well
and is convenient to mould and so is the most preferred.
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The largest collar section 16 is located just below the base 10. It
will be understood that in all cases this collar section will be in use once
the duct is attached, as it is the largest size collar. If the duct is to
attach
to a smaller sized collar then the duct is attached before the largest collar
section. If the duct attaches to the middle collar section then the smallest
collar section will be trimmed off and the only the middle and largest collar
section will remain. Finally if the duct attaches to the largest collar
section
the first two sections are trimmed off and only the largest collar section
remains. As explained in more detail below, the collar sections 14 and 12
are removed, but the section 18 and step 24 are kept.
As shown in Figure 1 the largest collar section forms a well 30
below the base although the well may be any shape in plan view, a
circular well is preferred as most air ducts are also circular. Thus, the
circular well provides an outer surface which can be easily fit and made
air tight with a connecting circular air duct.
Figure 1 shows a flapper valve hinge pin assembly 32. It consists
of a retaining ring 34, a hinge pin 36 extending across the diameter of the
retaining ring 34. Preferably the retaining ring 34 and hinge pin 36 are
formed from moulded plastic which has some resiliency. The retaining
ring 34 may have an external diameter which matches the internal
diameter of the well 30 just above the step 24. In this way the retaining
ring 34 may be fit inside of the well 30. Detents 35 (see Figure 2) may be
used to secure the retaining ring 34 within the well 30. Thus, in one
embodiment the retaining ring 34 may be pushed down into the well by an
installer and snap fit over the detents to be physically retained in the well
30. The present invention comprehends various ways of securing the
retaining ring 34 within the well including fasteners, adhesives, plastic
welding and even a simple frictional or interference fit and the like, but it
is
believed that the preferred form of securing the retaining ring in the well is
through a deflection over the detents as described above. As well,
although good results have been achieved with the retaining ring as
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described the present invention comprehends various ways that the hinge
pin 36 may be secured within the well. For example the hinge pin 36
could be made a simple straight member that fits into slots in the side
walls of the collar for example. All that is required is a hinge pin 36 that
can be aligned with the roof slope (namely, generally perpendicular to the
roof peak and sloped parallel to the plane of the roof slope) to permit the
smooth functioning of the flapper valves as described below.
Also shown are two flapper valves 50 and 52. Each of the flapper
valves includes a pair of snap connectors for securing the flapper valves
to the hinge pin. Each of the flapper valves has a generally semicircular
shape and the snap connectors 54 of one are offset relative to the snap
connectors 56 of the other. In this way they can be attached to the hinge
pin from opposite sides to form a circular flapper valve which covers the
airflow passageway through the well 30. It can now be appreciated that
the step 24 acts as a valve seat for the outer edges of the flapper valves
50, 52. In this way the flapper valves close off the air passageway
through the well 30 around the full circumference of the central well 30.
The snap connectors 54, 56 are sized and shaped to retain the
flapper valves onto the hinge pin, but are loose enough so that the flapper
valves can freely pivot about the hinge pin 36. In this way the present
invention provides a split flapper valve in which each half is smaller in
weight than one which needs to cover the whole opening and thus easier
to lift off the valve seat or step 24 than a full circular flapper valve as
shown in the prior art. As well the preferred form of the flapper valves is a
moulded plastic part which then rotates on and off of the valve seat
according to the air pressure from below. The use of light weight plastic
parts reduces if not substantially eliminates the noise that can be
associated with other types of valves which constantly open and close
and make a noise each time.
As can be seen in Figure 2 the valves when fully open only project
a small amount H above the base 10 of the vent. In this way the adaptor
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assembly of the present invention will fit below all manner of exterior roof
vent styles and designs. In terms of sizes, the steps 18, 20 and 22 may
be each made 1.5 inches long. Further, the diameter of the bottom of
step 22 may be 3.9 inches, the next step 4.9 inches and the last step 5.9
inches, with a 1 vertical taper. A duct 40 is shown in dotted outline
connecting to the smallest duct connector 12 by way of example.
Figure 3 is a cross-section along lines 3-3 of Figure 2 of the
present invention. As shown, rotation stops 70 may be formed into the
snap fittings 54, 56 to limit the over rotation of the flapper valves. This
has two desired effects including preventing the valves from getting to
upright in which case they may have a tendency not to properly close and
to prevent the tops of the valves from protruding very far above the
surface of the base making the present design a low profile design which
is compatible with many vent body styles which may be used to cover the
flapper valve adaptor. While any range of angles can be used,
reasonable results have been obtained by limiting the range of motion to
less than about 60 and most preferably to about 45 .
The installation of the present invention can now be understood.
The first step is to locate the ducting to be vented and to form a hole in
the roof deck at an appropriate location. Then the adaptor collar can be
sized to the ducting by removing any collar sections that are too small.
The removal can be done with a knife, scissors, sheers, snips or the like
as the plastic material while durable can be fairly easily cut. An area of
thinner plastic can be molded into the adaptor to facilitate such trimming.
The next step is to attach the duct to the appropriate collar using
convention methods which might include glue, adhesive, a duct clamp
and the like. Once the duct is secure the duct can be fed back down
through the hole and the base 10 secured to the roof in the normal
manner. As shown in Figure 1, markings 80 can be provided to assist the
installer in lining up the base. The base may be provided with visual
markings to help the installer orient the base correctly, such as having an
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Up arrow formed into the plastic or added by way of a label on both sides
of said base 10 so it can be correctly installed either above or below the
roof deck as the installer wishes. In the case of an outside installation,
the next step is the interleaving of the base 10 into a layered shingle
covering in the usual manner to ensure that the base is part of a
waterproof roof surface covering the underlying roof deck.
The next step is to insert and align the hinge pin. Typically a roof
surface will have a certain incline or slope. There is also typically a roof
peak, and a generally planar roof surface which slopes down and away
from the roof peak towards the eaves. In this way water is encouraged by
gravity to drain off the roof, into the eaves and then through downspouts
onto the ground. What is desired is to orient the hinge pin so that it
follows the slope or fall line. This is desired to keep the flapper valves
balanced and to prevent the flapper valves from being oriented in a way
that would require more effort to raise one flapper valve 50 as compared
to the other one 52, for example when the air pressure in the duct below
the vent is raised by means of a bathroom exhaust fan or the like. By
aligning the hinge pin at generally at about 90 to the roof peak, and
parallel to the slope of the planar roof surface the activation pressure
required for each flapper valve will be generally evenly balanced. The
flapper valves 50, 52 can be tested by turning on the fan, such as a
bathroom fan or range fan, to make sure the air pressure is enough to
open the flapper valves 50, 52 to the desired angle. The limit stops
effectiveness can also be evaluated. Then, the next step is to place a
conventional exterior roof vent overtop of the base to complete the
installation. As noted above the low profile H of the adaptor of the present
invention makes it suitable for many different forms of exterior roof vent.
It can now be appreciated that the present invention provides a
simple and easy to use adaptor which can be placed into the air flow
passageway of an air duct exhaust system to add a flapper valve closure
to the air flow passageway. The present invention may be used with
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many different styles and types of exterior roof vent and is inexpensive
and easy to install. Rather than requiring a dedicated type of exterior roof
vent body for the flapper valve, the present invention can be used with
any conventional mass market style of exterior roof vent, that provides a
modest amount of head space below the raised cover. Further, by
orienting the hinge pin axis generally perpendicular to the roof slope, the
valve configuration permits the use of two smaller half valves, which will
have substantially identical activation air pressures, and such activation
air pressures will be substantially the same across the normal range of
conventional roof slopes. In contrast the eccentric mounting of the hinge
axes of the prior art can result in larger changes in activation pressure
across the range of roof typical roof slopes.
It will be understood by those skilled in the art that various
modifications and alterations can be made without departing from the
broad scope of the appended claims. Some of them have been
discussed above and others will be apparent to those skilled in the art.
For example although a hinge pin support ring is shown, the hinge pin
could be supported in a number of other ways. All that is required is the
ability to orient the hinge pin to the slope to even out the resistance to air
pressure provided by both halves of the split flapper valve.
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