Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF THE INVENTION
The invention relates to air circulation systems for
large spaces, particularly for an auditorium, meeting hall,
or the like.
BACKGROUND OF THE INVENTION
The ventilation of large spaces, occupied by
substantial numbers of people, presents a series of
problems. In the first place the volume of air to be
circulated is very substantial, and at the same time,
typically the floor space will represent an area with a high
ceiling and a clear span, which will be used for seating. It
is not easy to place air circulating outlets in the floor of
such a seating area at appropriate locations. As a result,
in many such large spaces, such as auditoriums, air is
injected into these space from, for example, the ceiling,
and is removed at low level at side wall or floor locations.
This may set up undesirable air flow patterns or may have
circulation problems in some cases, and may create drafts.
Particularly in auditoriums, where a large number of
persons are sitting in close proximity to each other, such
persons will generate heat, and it is clearly desirable as
far as possible to continuously circulate air so as to
dissipate the heat. Where persons are seated close together
and in closely spaced rows, the sheer number of people will
of itself tend to provide a substantial blockage for air
flow. The result may be that although the air circulating
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system is designed to circulate a volume of air which is
theoretically adequate for the space, some persons may
experience excessive heat and stale air, and others may
experience drafts.
Another critical factor in the design of such air
facilities is the maintenance of low noise levels,
particularly in an auditorium. Attempts to increase air
circulation, simply by increasing the velocity of air flow
will tend to produce unacceptable noise levels, and will
interfere with the hearing of persons seated in the
auditorium, at least, the hearing of those persons seated in
proximity to the air outlets.
For all the reasons therefore it is desirable to
provide an air circulation system in which a relatively high
volume of air flow can be maintained, and in which the air
flow can be equalized throughout the auditorium for all
persons located there, and which maintains low noise levels,
so that the air circulation will not interfere with the
hearing of persons in the auditorium.
BRIEF SUMMARY OF THE INVENTION
With a view to satisfying the foregoing considerations,
the invention comprises an auditorium ventilation system for
supplying air in an auditorium with seats arranged in
groups, the system being operable without noticeable
interference with the sound characteristics of the
auditorium, and having a main supply duct, and a fan and air
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conditioning unit to cause air flow equal to between about
17 and 35 cubic feet per minute per seat, branch ducts
connecting to the main duct and underfloor plenum supplied
by the branch ducts, located beneath the floor levels of the
auditorium, a plurality of floor openings connecting with
the plenum, a plurality of air outlet registers located
above the floor level, connected to respective floor
openings, each air register being located beneath a
respective seat, and, each of the floor openings being
adapted to pass between about 17 and 35 cubic feet of air
per minute, at a velocity not exceeding about 500 feet per
minute, and the outlet registers reducing the velocity to
about between 50 and 100 feet per minute.
An amount of air approximately equal to the amount
being supplied to the auditorium is removed at the ceiling
(walls at high level) by a return fan. Air may be returned
to the supply fan, or exhausted from the building.
The various features of novelty which characterize the
invention are pointed out with more particularity in the
claims annexed to and forming a part of this disclosure.
For a better understanding of the invention, its operating
advantages and specific objects attained by its use,
reference should be had to the accompanying drawings and
descriptive matter in which there are illustrated and
described preferred embodiments of the invention.
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IN THE DRAWINGS
Figure 1 is a schematic side elevation illustration of
an auditorium, illustrating the ventilation system of the
invention;
Figure 2 is a schematic top plan view of the
ventilation system and showing typical air velocities at
various locations;
Figure 3 is an enlarged sectional side elevation of a
portion of Figure 1;
Figure 4 is a front elevational view of a seat as used
in the auditorium, showing the underseat ventilation outlet;
Figure 5 is a perspective of the outlet register of
Figure 4, and,
Figure 6 is a sectional side elevation of a floor step,
or ledge and seat ventilation arrangement, for certain parts
of the building.
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DESCRIPTION OF A SPECIFIC EMBODIMENT
Referring first of all to Figures 1 and 2 it will be
seen that the system as shown for the purposes of
illustrating the invention, and without limitation,
comprises a typical auditorium building indicated generally
as B. The building B for example is a theatre, a lecture
hall, or other large enclosed seating space. Typically in
such a building persons will be seated on seating indicated
generally as S located on the floor Fl of the building. In
the particular building B as illustrated there is a balcony
or mezzanine, and indeed in many such buildings there may be
two or three or more such mezzanines or balconies one above
the other, supporting further seats.
Seats S will usually be grouped in blocks or rows, and
may be separated by aisles.
Typically building B will have a floor Fl which in many
cases slopes upwardly from front to rear of the building and
will have a high ceiling C, which is characterized in many
cases by a free span, and an absence of any supporting
columns.
Consequently, due to the large size and the large
number of occupants, and the absence of columns and the
like, the positioning of ventilation ducts and outlets can
present something of a problem. Ventilation air will tend to
rise upwardly and pass over the heads of persons in the
building, due, in part, to the heat generated, for example
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by the persons in the building due to the fact that persons
will be located close to each other, creating a barrier to
air flow also and by the lighting. In accordance with the
invention, there is provided a ventilation supply system
comprising a main fan 10, and an air conditioning unit 12,
connected to a main duct 14. Duct 14 is connected to receive
outside air from intake I in a manner well known in the art
and may receive recycled return air as shown in phantom the
details of which are not illustrated for the sake of
simplicity.
The air conditioning unit 12 may provide and usually
will provide either cold air or warm air and humidification
or dehumidification, and also filtration, depending upon the
time of year and the setting of the controls.
The main duct 14 supplies a plurality of branch ducts
16, which extend in to an enclosed underfloor zone or plenum
18, defined by floor Fl, and sub-floor F2.
The underfloor plenum 18 is located so as to extend
beneath the groups or rows of seats S. There will be an
appropriate number of branch ducts 16 to service the plenum
area as defined by the floor Fl to distribute the air
evenly.
The ventilation also incorporates a plurality of return
openings (not shown) which will usually be located in the
ceilings, and will have a suitable return air fan and ducts
which may or may not provide for some recycled
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building air. Ducts in the ceiling and a return air fan will
convey the air from the room. Usually in such large
buildings B such return air systems are located up near the
ceiling or within the ceiling, since the warm air within the
building will rise upwardly. It is desirable to extract the
return air from the upper region of the building for this
reason.
In order to equalize flow from the main duct 14 to all
of the branch ducts 16, the main duct 14 is progressively
tapered as at 20 and 22, and terminates at a front
transverse duct 24. Duct 24 is located close to the stage,
at the front of the auditorium.
In order to further equalize air supply to the various
branch ducts 16, internal moveable deflector panels 26 are
provided. Panels 26 may be swung, so as to divert air
flowing from main duct 18 into branch ducts 16, when the air
ventilation system is being set up and adjusted.
Branch ducts 16 have a plurality of outlet nozzles 28,
in order to distribute air evenly on either side of the
ducts 16, and also at their ends.
Referring now to Figures 4,and 5, the seating S is
there illustrated in the form of an individual seat 30,
supported on a base 32, which may be some form of frame work
or legs such as is well known in the art and is not
illustrated in detail for the sake of clarity.
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An auditorium seat air outlet register will be seen to
comprise a hollow tubular body 34, which in this case is
cylindrical, having a lower flange 36 by means of which it
may be fastened to the floor Fl. It is open at its lower end
as at 38, and closed as at 40 at its upper end.
Body 34 is not necessarily cylindrical and may be a
variety of different shapes such as rectangular, elliptical
etc.
The hollow body 34 will have a plurality of air outlet
openings 42 located around the body, so as to provide an all
round air flow pattern around the seat.
Within the register pedestal an air flow guide 44 is
provided. Guide 44 is of generally frusto-conical shape,
with the tip of the cone being directed downwardly towards
the open end 38 of the body 34, and the wider upper end
being co-extensive with the perimeter of the closed upper
end 40 of the body 34.
The air flow guide 44 tends to smooth out turbulence
and vortexes within the body 34, which might otherwise
arise, and to distribute the air evenly. For the purpose of
communicating between the underfloor plenum 18 and the
individual seat register 34, there will be respective air
passageways 46 formed in the floor Fl at spaced intervals
along each seating row, registering with the register 34 of
each respective seat.
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Each of the passageways 46 will be seen to be of a
predetermined diameter d which is substantially less than
the diameter D of the hollow body 34. The cross-section area
A body 34 will be at least double the cross-section area a
passageway 46.
Passageways 46 could be drilled after pouring floor Fl,
but are preferably formed by hollow sleeves which are placed
in position prior to pouring. The sleeves are flush with the
top and bottom surfaces of floor F1.
Referring now to Figure 2, the operation of the
ventilation system in accordance with the invention is
illustrated there in terms of a typical auditorium shown
schematically and having seats indicated as S. Some such
seats S are shown in Figures 1 and 3, and in practice there
would of course be many more.
The fan 10 is operable to draw fresh air (with or
without some recycled building air ) and pass it through the
air conditioner 12 (filtering, heating or cooling, and
humidifying, or dehumidifying, as required) and
along main duct 14. The volume of air passing through main
duct 14 for a given time period will be equal to preferably
between about 17 and 35 cubic feet per minute per seat in
the auditorium.
The air is then passed to the branch ducts 16 and via
outlets 28 and then to the underfloor plenum 18 which is a
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hollow area between Floors Fl and F2 and thus to the seating
rows.
As explained above the plenum 18 is a hollow area
between floors Fl and F2 and extends beneath the rows of
seats S, the term "row" being used here without excluding
groupings other than in actual rows.
The air flowing in main duct 14 will typically flow at
a velocity in the region between about 700 and 800 feet per
minute. Values below this however may be used, where it is
possible to increase the size of the duct work. Velocities
higher than this are undesirable, since they tend to produce
excessive noise. The air velocity in the branch ducts 16 is
about 350 - 500 feet per minute. Within the plenum 18 such
air flow will maintain a slight positive pressure.
From the plenum 18, the air passes through the air
passageways 46 formed in the floor F. The velocity here will
be about 500 feet per minute, or less. The volume of air
flow through each passageway 46 will be between about 17 and
35 cubic feet per minute.
The air then flows upwardly into the individual seat
registers 34. The passageways 46 have a diameter d, and as
giving a cross-sectional area of passageway 46 which is
about ~ that of body 34.
As a result, air passing through the passageway 46 then
reduces
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in velocity, and flows out through the openings 42 at an
exit velocity in the region of 70 to 100 feet per minute.
It will thus be seen that by the operation of the
invention adequate air flow is supplied for each person
seated in a seat S in the building, and at the same time the
noise level resulting from the distribution of air is
reduced to a minimum, so as to avoid interference with the
sound characteristics of the building.
It will be appreciated that these numbers and
calculations are based typically for the purposes of
calculation only on the number of seats for the audience in
the building.
Typically the stage in the building will be supplied
with separate air handling facilities (not shown), so that
it is not involved in the equation.
In the typical auditorium there will also be staff
and attendants, but the numbers are relatively small in
relation to the total audience and they are included in the
above calculation.
In cases where the audience is at its maximum number
and the attendants stand or sit on stools, the attendants
will benefit from the overall air circulation provided by
this invention and their effect on the total air flow is
included in the calculation above.
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In some cases there will be a few empty seats left, and
in practice the staff and attendants will often be able to
sit down in unoccupied seats during the performance.
Consequently, by basing the calculations on the number
of seats provided in the auditorium, in most cases, a slight
excess of air circulation is provided, over and above the
actual requirements of the actual number of persons
occupying the seating space of the building at any one time.
Referring now to Figure 6, a somewhat modified form of
arrangement of floor and seating is illustrated, which may
be used in some cases, in parts of the mezzanines, such as
the dress circle, balcony etc, in locations where it may be
required.
It will be appreciated that in many auditoriums the
floor is not continuously sloping from front to rear. In
various places there may be steps or ledges, where a portion
of the floor is raised or stepped relative to the floor in
front of it.
In this case, an arrangement may be used as shown in
Figure 6.
In this case the floor Fl is shown having a ledge or
step L. A row of seats S may be located immediately in front
of the ledge L. For various reasons it may be difficult to
provide openings immediately beneath this row of seats.
In order to overcome this problem, in this case,
generally angled openings 50 may connect between the plenum
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18, and the space behind each seat. The seats S in this row
will be supported typically on standard frame work or legs
(not shown).
In these cases air will simply be released from the
openings 50 behind the lower region of each seat.
In order to avoid possible drafts a deflector or baffle
52 of angle-shaped section will be secured to the vertical
portion of the ledge L, spaced from but registering with the
opening 50.
In this case therefore air will flow from behind each
seat, rather than from beneath each seat and be diverted
sideways by the baffle 52.
In some cases seats can be removed to provide space for
audience members in wheel chairs. The registers 34 are
removed and caps (not shown~ are put over the passageways 46
and platforms (not shown) are installed to accommodate the
wheel chairs. It is possible to incorporate air flow from
some of the passageways 46 into the platforms being used for
the wheel chairs such that the wheel chair audience members
benefit from the floor supply system as well.
The foregoing is a description of a preferred
embodiment of the invention which is given here by way of
example only. The invention is not to be taken as limited
to any of the specific features as described, but
comprehends all such variations thereof as come within the
scope of the appended claims.
