Note: Descriptions are shown in the official language in which they were submitted.
CA 02369490 2002-01-25
VENT TERMINATION RECEPTACLE WITH DAMPER
FIELD OF THE INVENTION
This invention relates to vent termination receptacle with an integral
damper.
BACKGROUND
In the construction of HVAC systems, a centrai air handfer delivers air
to the interior of the structure through a main plenum duct, and a series of
branch
ducts which terminate at a vent termination receptacle which attaches to a
vent plate
for controlling the discharge of air into the space. With a higher pressure
air system,
the vent termination receptacle includes a housing which is preferably of
greater
cross sectional area than the supply duct so that the air leaving the ductwork
at the
vents expands rapidly as it enters the housing and creates a lower air
pressure zone
around the vent. This is a practical application of Bernoulli's theorem and
the
Venturi effect. One of the problems of higher pressure air systems (commonly
known as Hi-Velocity systems) is that conventional damper assemblies such as.
those described in U.S. Patents 4,513,655, 4,628,954, 4,653,725, 5,411,438,
5,806,830, 5,813,430, 5,857,617, 5,921,277, and 6,082,704 will cause air
noise.
In the history of these Hi-Velocity style systems, no damper has been
truly effective without causing noise.
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SUMMARY
It is one object of the present invention, therefore, to provide an
termination receptacle for an air supply duct which includes an integral
damper
operable by the user to vary or shut off the air flow through the duct.
According to a first aspect of the invention, therefore, there is provided
a termination receptacle for an air supply duct comprising:
a housing having a wall surrounding an axis of the housing;
an inlet pipe arranged for connection to the air supply duct for receiving
air therefrom;
the inlet pipe being connected to the wall of the housing generally at
right angles to the axis so as to communicate the air from the duct through an
opening in the wall into the housing;
the housing having one end closed and an opposed open end such
that the air supplied into the housing passes from the housing through the
open end;
the housing having a mounting flange member at the open end for
attachment of the housing to a mounting surface such that the axis is
generaliy at
right angles to the mounting surface;
a damper sleeve member having an open discharge end and an
insertion portion extending from the discharge end and arranged for insertion
into
the open end of the housing for receiving the air therefrom
the wall of the housing defining at least a portion thereof at the opening
which is circular cylindrical at least partly surrounding the axis;
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the insertion portion of the damper sleeve member being arranged
rotate around the axis and being shaped to cooperate with the circular
cylindrical
portion of the housing to move gradualiy between a first position in which the
opening is fully exposed by the insertion portion allowing passage of air from
the
inlet through the full area of the opening into the housing and a second
position in
which the insertion portion fully covers the opening thus closing off flow of
air
through the opening into the housing such that the insertion portion acts as a
damper.
Preferably the vent plate itself forms a part of the combination and is
attached to the damper sleeve member or is formed as an integral component
with
the damper sleeve member so that the damper sleeve member is rotated about the
axis by the user rotating the vent plate about the axis.
Thus according to a second aspect of the invention there is provided a
termination receptacle for an air supply duct comprising:
a housing having a wall surrounding an axis of the housing;
an inlet pipe arranged for connection to the air supply duct for receiving
air therefrom;
the inlet. pipe being connected to the wall of the housing generally at
right angles to the axis so as to communicate the air from the duct through an
opening in the wall into the housing;
the housing having one end closed and an opposed open end such
that the air supplied into the housing passes from the housing through the
open end;
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the housing having a mounting flange member at the open end for
attachment of the housing to a mounting surface such that the axis is
generally at
right angles to the mounting surface;
a damper sleeve member having an open discharge end and an
insertion portion extending from the discharge end and arranged for insertion
into
the open end of the housing for receiving the air therefrom
a vent plate member;
the vent plate member having a plate portion with a central perforated
discharge area which is perforated for the passage of air therethrough and a
peripheral surrounding flange;
the vent plate member having a projecting connecting portion
extending from the plate portion generally at right angles to the plate
portion for
connecting the vent plate member to the damper sleeve member at the open end
thereof for communication of the air from the housing through the damper
sleeve
member and through the central perforated discharge area;
the connecting portion and the damper sleeve member being arranged
such that the vent plate member is maintained attached thereto with the plate
portion
generally at right angles to the axis so as to lie parallel to the mounting
surface on a
side thereof opposite to the mounting flange member;
the connecting portion and the damper sleeve member being arranged
such that rotation of the vent plate member about the axis causes common
rotation
of the damper sleeve member about the axis therewith;
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the wall of the housing defining at least a portion thereof at the opening
which is circular cylindrical at least partly surrounding the axis;
the insertion portion of the damper sleeve member being arranged
rotate around the axis with rotation of the damper sleeve member and being
shaped
to cooperate with the circular cylindrical portion of the housing to move
gradually
between a first position in which the opening is fully exposed by the
insertion portion
allowing passage of air from the inlet through the full area of the opening
into the
housing and a second position in which the insertion portion fully covers the
opening
thus closing off flow of air through the opening into the housing such that
the
insertion portion acts as a damper.
Preferably the insertion portion incfudes a circular cylindrical wall
portion at the circular cylindrical portion of the housing. It is not
necessary for either
portion to form a complete cylinder surrounding the axis since the cylindrical
portions
need only extend sufficiently around the axis to allow the movement through
roughly
ninety degrees between the two positions. The remainder of the portions can
then
differ from the cylindrical shape so long as they do not interfere with the
movement.
Preferably the insertion portion has an outer surface in sliding fit with
an inner surface of the circular cylindrical portion of the housing. In this
case one or
both of the portions in sliding fit is formed of plastics material so as to
ensure a close
fit and a sealing action.
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Preferably the insertion portion is substantially circular cylindrical in
shape with a cut out at the opening so that the cut out is provided only at
the
opening and has side edges parallel to the axis.
Preferably the insertion portion extends substantially to the bottom of
the housing.
Preferably the inlet pipe is of smaller cross-sectional area than the
housing so as to allow expansion of the air as it enters the housing, although
this is
not essential to the operation.
Preferably the vent plate member and the damper sleeve member are
separate and connected by cooperating elements arranged to allow adjustment of
the angular position of the vent member relative to the damper sleeve member.
Alternatively the vent plate and sleeve can be integral. Alternatively the
vent plate
and the sleeve can be separate and the sleeve rotatable independent of the
vent
plate so that the vent plate remains at a fixed position relative to the
mounting
surface while the sleeve can be rotated by the user by a suitable lever.
Preferably the damper sleeve member includes an interconnecting
element for holding the damper sleeve member in the housing to prevent it from
failing out in the event that the housing in installed up side down in a
ceiling or in the
event that the housing is installed with the axis horizontal.
Preferably the housing has a depth between the flange member and
the bottom which is no greater than 3.5 inches thus allowing the housing to be
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installed in the space between conventional two by four studs. However larger
or
smaller sizes can also be used and the construction is not in any way size
specific.
Preferably the damper sleeve member includes two axially spaced
cylindrical portions defining a shoulder therebetween.
Preferably the damper sleeve member includes an outwardly
projecting tab on an outer surface thereof for projecting into an annular
locating slot
on the housing, which acts to hold the sleeve in place and also acts to limit
the
angular movement of the sieeve around the axis.
Preferably the vent plate member and the damper sleeve member are
separate and connected by cooperating, elements which comprise longitudinally
extending ribs and grooves.
Preferably the insertion portion of the damper sleeve member includes
a closed end at the closed end of the housing. In this arrangement, the closed
bottom end is preferably shaped to provide a smooth curved guide surface at
the
opening to guide air from the inlet pipe to tum through ninety degrees to flow
axially
along the housing.
Since having the ability to shut off vents by the end user is desirable,
the configuration is provided in the embodiment as described hereinafter in
which
the velocity and pressure relationship of the airflow is altered sufficiently
to allow for
a damper that causes minimal noise and minimal air leakage.
This arrangement as described hereinafter provides a vent termination
receptacle with integral damper for the Heating, Ventilation, Air Conditioning
(HVAC)
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g
Industry, particularly for higher pressure air systems. Normally the vent
plate has
vanes which are simply straight so as to have no effect on the direction of
the air
flow. However in some cases it may be desirable to provide directional vanes
in
which case the vent plate can be installed, by rotating the vent plate
relative to the
sleeve, with the airflow pointing in any direction needed by the application.
An injection molded plastic, two piece vent boot and damper assembly
as described hereinafter provides a simple, effective, and economic solution
to this
problem. The benefits of a plastic assembly are an inherent sound acoustic
property
greater than that of metal assemblies, as well as a resistance to. mal-
forming,
moisture, mold, and rust.
Air leakage around vanes or flaps that is minimal with lower air
pressure systems, is greatly amplified with Hi-Velocity systems, so a tight
fit, easily
reproducible assembly, as described hereinafter is provided. To further
compound
the design problem, it is desirable that the entire assembly is small enough
to fit in a
standard construction 2 x 4 stud wall to allow for sidewall discharge of the
air.
The housing preferably has a barrel with a diameter larger than that of
the branch ductwork causes a change in the pressure to velocity ratio of the
airflow,
which helps minimize a noise increase easily experienced with higher pressure
air
terminations. The damper sleeve which snugly turns inside this barrel, allows
for a
closure of the airflow without the "whistling" experienced from conventional
dampening methods. A matching groove and lip on the two pieces further reduces
air leakage while also preventing the damper tube from falling out of place
when the
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assembly is installed in a ceiling pointing downward.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate an exemplary
embodiment of the present invention:
Figure 1 is n isometric view showing a first embodiment of the
invention.
Figure 2 is a side elevational view partly in phantom of a second
embodiment of the invention.
Figure 3 is a front elevational view partly in phantom of the second
embodiment of the invention.
Figure 4 is a cross sectional view along the lines A-A of Figure 2.
Figure 5 is a cross sectional view along the lines B-B of Figure 3.
Figure 6 is a top plan view partly in phantom of the second
embodiment of the invention.
DETAILED DESCRIPTION
In Figure 1 is shown a first embodiment of the invention in a simplified
shape and form which shows the principle of operation of the device.
The duct system from a central air source (not shown) provides.a
branch duct 10 communicating to a termination receptacle generally indicated
at 11
which co-operates with a vent plate 12. The termination receptacle is formed
in two
pieces including a housing 13 and a damper sleeve 14.
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The housing 13 forms a generally cylindrical wall 15 with a closed
bottom end 16 and an open top end. At the top end is provided a peripheral
flange
17 which as shown is square in plan view but can be circular or can be formed
simply by a plurality of tabs with the flange lying in a plane which is at
right angles to
the longitudinal axis 18 of the cylindrical housing 13. The flange 17 is
attached to
the underside of a floor 19 forming a mounting surface for the housing.
In the alternative the flange can be mounted on the inside surface of a
sheathing material forming a wall surface or on the top surface of a sheathing
material forming a ceiling. Thus the housing is held in place in a fixed
position with
1'0 the axis 18 at right angles to the duct 10.
An inlet pipe 20 is connected to the duct 10 by suitable connection
system and is formed as an integral structure with the housing providing an
opening
between the end of the inlet pipe and the interior of the housing. The inlet
pipe is
circular in cross section so that the opening is also circular and extends
through the
cylindrical wall 15 to the hollow interior of the housing. The inlet pipe is
of smaller
cross sectional area and thus smaller diameter than the housing 13 so that air
entering the housing from the inlet pipe expands and slows in a conventional
manner used in high pressure systems of this type.
The damper sleeve member 14 forms a generally cylindrical shape
having an outer surface 14A which co-operates with an inner surface of the
cylindrical wall 15 of the housing in a sliding fit so that the damper sleeve
can rotate
around the axis 18 within the housing 15. A bottom edge 22 of the sleeve
extends to
CA 02369490 2002-01-25
the bottom of the housing to a position below the inlet pipe so as to extend
to a
portion of the housing beyond the bottom of the inlet pipe.
The longitudinal extent of the housing from the base 16 to the flange
17 is 3.5 inches in length so that it can fit underneath the floor sheeting 19
and
between the floor support studs 23 of a conventional 2 x 4 dimension.
The vent plate 12 includes a central area (not visible) which is
perforated with vent openings to allow air from the housing to escape through
the
vent plate into the space above the floor sheathing. Around the central
discharge
area of the vent plate is provided a flange section 12A which covers an
opening 19A
in the floor sheathing so as to provide an attractive appearance for the
discharge
vent of the air supply system. On the back of the vent plate is provided a
collar 24
which inserts into an upper discharge end 25 of the cylindrical sleeve 14A as
a tight
fit. The angular orientation of the vent plate relative to this sleeve can be
adjusted
by pulling the collar from the sleeve and rotating the vent plate relative to
the sleeve
and reinserting the collar into the sleeve at the required angular
orientation. When
inserted the collar is held in place within the end of the sleeve by suitable
projections
such as a peripheral rib which frictionally engages the sleeve to hold the
vent plate
attached to the sleeve. Thus manual rotation of the vent plate causes similar
rotation of the sleeve about the axis 18 within the housing 13.
The sleeve includes a cut-out 26 with a curved top edge 26A and two
vertical sides 26B and 26C each parallel to the axis 18. When the cut-out is
thus
aligned with the inlet opening of the inlet pipe 20, air can flow from the
inlet pipe into
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the hollow interior of the housing that is within the hollow interior of the
sleeve since
the sleeve is a close fit on the inside of the housing. However when the
sleeve is
rotated relative to the housing one of the edges 26B or 26C crosses over into
the
area of the opening of the inlet thus cutting off a portion of the area of the
opening to
reduce the amount of air flow through the inlet pipe into the housing. When
rotated
through an angle of the order of 90 , the sleeve fully covers the opening of
the inlet
pipe to prevent air passage into the housing thus closing off that particular
duct 10.
The damper sleeve thus provides a simple technique for closing off the
duct 10 or for reducing air flow through the duct 10 simply by rotating the
vent plate.
The tight fit of the sleeve within the housing prevents or significantly
reduces the
passage of air around or through gaps in the system so that there is little
noise or
whistling effect due to the high pressure flow. When fully closed by the
sleeve being
turned, the opening of the inlet pipe is fully closed by the outside surface
of the
sleeve and the escape of air around the opening into the space between the
sleeve
and the housing is prevented or inhibited by the close tolerances between the
surfaces and by the fact that the closure is formed not by a simple edge but
by
portions of the outside and inside surface respectively of the sleeve and
housing.
In the embodiment shown in Figure 1, the housing can be formed of
metal in conventional manner and the sleeve formed from plastics material so
as to
provide a reduction in friction between the outside surface of the sleeve and
the
inside surface of the housing. Alternatively both pieces can be formed from
molded
plastics material.
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Turning now to the second embodiment shown in the remaining
figures, the principle of operation as previously described is identical
except that the
parts are molded to provide particular co-operating shapes by injection
molding from
a suitable plastics material. Thus the inlet pipe 20 leading to the opening
20A in the
housing 13 is formed as an integrally molded structure with the housing.
Further,
the housing is molded to define a shoulder 30 between two cylindrical portions
31
and 32 so that the shoulder co-operates with a corresponding shoulder 33
formed on
the sleeve between two cylindrical portions 34 and 35. The position of the
shoulder
co-operates with or is located at the bottom end of the collar 24 of the vent
piate 12.
Thus the sleeve can be inserted until the shoulder 33 sits on the shoulder 30
so as
to locate the depth of the sleeve within the housing.
In this embodiment, the bottom end of the sleeve is closed by a bottom
end portion 40 which is molded with the wall 35. The bottom end portion 40 as
best
shown in Figures 4 and 5 provides a surface which is curved so as to match the
bottom circular portion of the opening 20A so that air entering the housing
through
the opening 20A passes smoothly onto the surface defined by the bottom portion
40
as a continuation of the pipe surface. The bottom portion 40 is also curved as
shown in Figure 5 to define a semi-circular curved portion 40B which extends
from
the bottom surface portion of the inlet pipe 20 through 90 in a smooth
curvature
from a horizontal surface portion 40C at the inlet pipe to a vertical portion
40D at the
wall 35. Thus the air entering from the inlet pipe is smoothly curved to move
from a
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horizontal direction at the inlet pipe to a vertical direction along the axis
18 to the
perforated vent area 12B of the vent plate 12.
The outside surface of the collar 24 carries a plurality of ribs 24A which
co-operate with grooves 34A in the wall 34 so as to act as a friction fit by
which
rotation of the vent plate 12 causes rotation of the sleeve 14. However the
vent
plate can be pulled out of the sleeve, rotated relative to the sleeve and
reinserted so
as to change the angular orientation with the grooves and ribs being arranged
to
locate and hold the angular orientation once set. This can be used to adjust
the
angular position of the vent openings of the vent area 12B relative to the
location of
the opening 20A so as to direct the air in the required position into the
space.,
A notch 50 provided on the outside surface of the wall 34 as best
shown in Figure 5 engages into a slot 32A in the wall 32 of the housing when
the
sleeve is inserted into the housing to the required position. The notch 50
includes a
horizontal upper surface which resists the sleeve being pulled back out of the
housing together with a chamfered or inclined lower surface 51 which allows
the
sleeve to be simply popped into place by pressure downwards into the housing.
A
relieving slot 52 in the flange 17 allows the portion of the wall 32 at the
slot 32A to
flex outwardly to allow the notch 50 to pass. The slot 32A extends around an
angle
of the order of 1500 as shown at 32B in Figure 6. The notch 50 and the slot
32A
thus limits the angular rotation of the sleeve relative to the housing and
thus limits
the angular rotation of the vent plate.
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While one embodiment of the present invention has been described in
the foregoing, it is to be understood that other embodiments are possible
within the
scope of the invention. The invention is to be considered limited solely by
the scope
of the appended claims.
