Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to an improved vent-
feting unit particularly suited for animal buildings.
It is well known that ventilating units are used
in most of the buildings, especially the animal buildings to
circulate air in the building, and/or change air in the
building. The air circulation step maintains a more uniform
air temperature within the building and the air changing step
allows introduction of air fresh within the building. In
some buildings, such as hog barns, it is particularly important,
to protect the health of young pigs, to maintain the air
temperature within close limits and also to change the air
frequently so that it does not become poisonous from gases
generated from pig waste.
In practice, it is rather difficult to change
air while keeping the air temperature in the building within
desired limits. However, if the incoming fresh air is added
generally in the same amount as the amount of stale air
removed, and properly mixed with the building air on entering,
the building air can be changed while controlling its
temperature.
United States Patent No. 4,336,748 issued on June
29, 1982 in the name of Axis Products Ltd. t discloses a Yen-
tilting unit for both circulating air within a building
and/or changing the air in the building while maintaining a
relatively constant temperature. The unit employs an air
intake duct and an adjacent air exhaust duct, with a fan in
each duct. Valve means are provided in the unit for directing
any proportion of the air removed from the building via the
exhaust duct back into the building via the intake duct.
The valve means can be set at any position between, and
including, a first position where none of the outgoing air
is directed back into the building and a second position where
it is all directed back. In the first position, rapid air
change occurs, which may be necessary if dangerous air
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conditions build up within the building. In the second
position, no air change occurs, the air within the building
being merely recirculated. Normally, the valve means is
somewhere between the two positions, allowing some air change
while mixing the fresh incoming air with building air to
maintain a more stable temperature.
The ventilating unit disclosed in United States
Patent No. 4,336,748 works satisfactorily. However, the
use of two fans, one in the exhaust duct and one in the
intake duct, makes it costly. In addition, the air emerging
from the intake duct of this unit is not distributed far
enough away from the inlet of the exhaust duct, thereby
substantially reducing its efficiency in changing the air.
Moreover, the unit cannot be as efficient and/or quiet as it
could be due to its asymmetry.
The object of the present invention is to provide
an improved ventilating unit which is more efficient and
; relatively cheaper in cost and operation than the already
known units.
In accordance with the present invention, there is
provided a ventilating unit for circulating and/or changing
air, which unit requires only a single fan. In addition, the
unit is constructed to have symmetrical air flow in, and
through it, thereby making it more efficient than known units.
Further, the unit is constructed to separate the various air
flows as they enter or leave the unit as much as possible
thereby further increasing efficiency.
In accordance with the present invention, the
ventilating unit is provided with a central exhaust duct and
an intake duct on each side of the exhaust duct. Air transfer
openings are provided between the exhaust duct and each
intake duct. A single fan in the inlet of the exhaust duct
serves to circulate air and/or change air in a building
serviced by the unit. A first valve means is provided in the
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exhaust duct at its outlet end, and a second valve means is
provided in each intake duct at its inlet end. The first
and second valve means are movable between, and including: a
first position, where both the outlet of the exhaust duct,
and the inlets of the intake ducts are closed, and the air
transfer openings between the exhaust duct and the intake
ducts are opened; and a second position, where the outlet of
the exhaust duct, and the inlet of the in-take ducts are open
and the air transfer openings between the exhaust and intake
ducts are closed.
In the first position, the fan circulates the air
within the building through the housing with the first valve
means symmetrically dividing the incoming air in the exhaust
duct for return via the openings and the intake ducts. In
the second position, the fan exhausts stale air from the
building through the exhaust duct. The reduced pressure
within the building draws fresh air in through the intake
ducts. Usually the valve means are located in between the
two positions thus allowing part of the building air drawn
into the exhaust duct to be exhausted, and part to be
returned, and mixed, with the replacement fresh air drawn in
through the intake ducts. The outlets of the intake ducts
are arranged to divert the air laterally of the inlet of the
exhaust duct. Similarly the inlets of intake ducts are
arranged to draw air in laterally from the unit, and the
outlet end of the exhaust duct, to more efficiently change
; the air.
The invention is particularly directed toward a vent-
feting unit for use in a building particularly an animal building
to circulate and/or change air in said building said unit comprising:
- a housing having one side intended to be located
within the building to be serviced and another side to be
located outside said building, said housing being
partitioned to define a first lateral intake duct, a second
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lateral intake duct and an exhaust duct centrally positioned
between the first and second intake duct, said exhaust duct
having an inlet on said one side of the housing and an
outlet on said other side of said housing, each of said
intake ducts having an inlet on said other side of the
housing and an outlet on said one side of said housing, said
housing also having air transfer openings for connecting the
exhaust duct to the intake ducts,
- a single fan mounted in the inlet of the exhaust duct
for drawing air from the building into the exhaust duct;
- first valve means mounted in the housing at the
outlet of the exhaust duct said first valve means comprising
a pair of flaps;
- second and third valve means mounted in the housing
.15 at the inlets of the first and second intake ducts
respectively;
- means for moving the first valve means to any
position between, and including, a first position wherein
the flaps of said first valve means close the exhaust
outlet and leave the transfer openings opened, and a second
position wherein the exhaust outlet is left opened and said
flaps close the transfer openings,
- said means for moving the first valve means
comprising a motor for moving one flap, and link means
extending between the two flaps for having the one flap move
the other flap when the one flap moves,
- means for moving the second and third valve means
between, and including, a first position wherein the intake
inlets are closed and a second position wherein the intake
inlets are opened,
- said means for moving the second and third valve
means comprising first linkage means connecting one of the
flaps of the first valve means to the third valve means and
second linkage means connecting the other flap of the first
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valve means to the second valve means,
- a firs-t air temperature sensor located at a remote
distance from the unit inside the building, said first
sensor being connected to the fan to control its speed,
- a second air temperature sensor located in the
housing close to the exhaust inlet, said second sensor being
connected to the motor used for moving the flaps of the
first valve means to adjust the position of said flaps
between, and including, their first and second respective
positions, and
- an adjustable limiting circuit connected between the
second sensor and the motor used for moving the flaps to
prevent said flaps from being continuously and permanently
adjusted,
whereby, in use,
adjustment of the first, second and third valve means
in their first respective positions causes all the air drawn
from the building into the exhaust duct by the fan to be
returned through the intake ducts via the transfer openings
after having been substantially equally divided
there between,
adjustment of said first, second and third valve means
in their second positions causes all the air drawn into the
exhaust duct by the fan to be exhausted and fresh makeup air
from the outside to be drawn in through the intake ducts;
and
adjustment of said first, second and third valve means
in intermediate positions between their first and second
respective positions causes part of the air drawn in the
exhaust duct to be exhausted and part to be returned and
mixed with fresh air drawn in through the intake ducts.
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The invention will be better understood upon reading
of the following non-restrictive description of a preferred
embodiment thereof, made with reference to the accompanying
drawings in which:
Fig. 1 is a perspective view ox a ventilating
unit according to the invention;
Fig. 2 is a side elevation Al view of the ventilating
unit of jig. 1 with the side panel removed;
Fig. 3 is a plan view of the ventilating unit
of fig. 1 with the top panel removed; and
Fig. 4 appearing on the same sheet of drawings as
Fig. 1, and Figs. 5 and 6 are schematic plan views of the
ventilating unit of figs 1 to 3, with the top panel removed,
showing the valve means in various positions.
The ventilating unit 1 shown in Figs. 1 to 3, has
a housing 3 that can be made, for example, of stainless
steel. The housing 3 is defined by top and bottom panels 5
and 7 joined by end panels 9 and 11. Two intermediate
partitions 13 and 15, extending parallel to the end panels
9 and 11, divide the housing 3 into a central exhaust duct
17 and two intake ducts 19 and 21, one on each side of the
exhaust duct 17. The exhaust duct 17 is approximately twice
the cross-sectional area of each intake duct 19 and 21.
One side 23 of the housing 3, namely the inner side
of the housing to be located within a building to be serviced
by the unit 1, has a central inlet 25 for the exhaust duct
17 and outlet openings 27, 29 for the intake ducts 19, 21.
The outlet openings 27, 29 open into cowls 31, 33 mounted
on the housing 3 as shown in Fig. 4. The cowls have outlet
openings 35, 37 which open sideways to direct air away from
exhaust duct 17 in a direction transverse to the end panels
9 and 11 and thus to the axis of the central inlet 25. This
particular arrangement is very interesting in that it allows
better distribution and circulation of air inside the building.
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Advantageously, angularly adjustable fins 36 and 38 may be
provided in the outlet openings 35 and 37 of the cowls 31
and 33 respectively for adjustable directing the exhaust
air and thus further improving its distribution and circulation
inside the building. These fins may be vertical as shown
in the drawings, or horizontal or both vertical and horizontal.
On the other side 39 of the housing 3, namely the
outer side located outside a building to be serviced by the
unit 1, there is a central outlet opening 41 for the exhaust
Dakota 17 and a pair of inlet openings 43 and 45, one on each
side of the outlet 37, for the intake ducts 19, 21 respectively.
Each inlet opening 39, 41 extends well into the end panels
9, 11 respectively of the housing 3 to draw air into the
intake ducts laterally of the housing 3.
AYE fan 47 is mounted to the housing 3 within the
exhaust duct 17 at its inlet opening 25. A first air transfer
; opening 49 is provided in the partition 13 connecting the
exhaust duct 17 to the first intake duct 19, while a second
air transfer opening 51 is provided in the partition 15
connecting the exhaust duct 17 to the second intake duct 21.
First valve means 53 are provided in the exhaust
duct 17 at its outlet 37. This first valve means 53 comprise
a pair of flaps 55 and 57. The flap 55 is pivot ably mounted
at one edge 59 to one edge 61 of the partition 13 defining
the transfer opening 49. The flap 57 is pivot ably mounted
at one edge 63 to one edge 65 of the partition 15 defining
the transfer opening 51. The flap 55 is sized to close the
first transfer opening 49 whereas the flap 57 is sized to
close the second transfer opening 51. The flaps 55 and 57
are movable between a first position where their free edges
65, 67, opposite their one edges 59, 65, abut, the flaps 55,
57 then forming a V-shape as shown in Fig. 4; and a second
position, shown in Fig. 5, where the flaps 55 and 57 are
parallel to each other. In the first position, the flaps 55
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and 57 are parallel to each other. In the first position,
the flaps 55 and 57 close the outlet 41 of the exhaust duct
17 and open the air transfer openings 49 and 51 in the part-
lions 13 and 15. In this position, the flaps 55 and 57 split
the incoming air stream in the exhaust duct 17 and divert
the air generally equally into the intake ducts 19 and 21 for
return to the building via the cowl outlets 35 and 37. Thus,
the air is recirculated in the building. In the second position
of the flaps 55 and 57 shown in Fig. 5, the exhaust duct
outlet 41 is fully opened and the air transfer openings 49
and 51 are closed. The air is now exhausted from the building.
Second and third valve means 71 and 73 are provided in
the intake ducts 19 and 21 respectively. The second valve
means 71 comprises a pair of flaps 75 and 77 pivotal mounted
at one edge 79, 81 respectively in the inlet opening 43 of
intake duct 19 between the panels 5 and 7. Similarly, the
third valve means 73 comprises a pair of flaps 83 and 85
pivotal mounted at one edge 87, 89 respectively, in the
inlet opening 45 of the intake duct 21~ The flaps 75, 77
and the flaps 83, 85 are simultaneously movable between, and
including, a first position where each pair is aligned and
closes the inlet openings 43 and 45 respectively, and a second
position where each pair is parallel and opens the inlet
openings 43 and 45. In the first position shown in fig. 4,
each pair of flaps 75, 77 and 83, 85 extends at an angle across
the intake ducts 19 and 21 respectively that they are mounted
in. This position permits the flaps 75, 77 to help divert
the air from the flap 55 in the first valve means 53 into the
intake duct 19, and the flaps 83, 85 to help divert the air
from the flap 57 into the intake duct 21 when the flaps 55,
57 are in their first position. In the second position shown
in Fig. 5, the flaps 75, 77 and 83, 85 fully open the intake
ducts 19, 21 allowing fresh air to be drawn into the building
through the ventilating unit 1 while building air is being
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exhausted through the exhaust duct 17 with the first valve
means 53 in its second position. In any intermediate position
as shown in Fig. 6, the flaps 75, 77 and 83, 85 allow part
of the building air drawn into the exhaust duct 17 to be
exhausted, and part to be returned, and mixed, with fresh
air drawn in through the intake ducts 19 and 21. The ratio
of the part of building air exhausted through the exhaust duct
17 to the part of this building air returned in, depends
on the location of the flaps 75, 77 and 83, 85 in between
their first and second positions, and the location of the first
valve means 53 in between its first and second positions.
In any case, the use of pairs of flaps 75, 77 and 83, 85
instead of single flaps for opening and closing the intake
ducts 19 and 21 substantially improves the mixture and
distribution of the fresh air drawn in through the intake
ducts, with the part of building air selected to be returned
in the building.
First means are provided for moving the first valve
means 53 between its first and second positions. The first
valve moving means 95 comprises a motor 97 mounted to the
panel 7 just outside the outlet 41 of the exhaust duct 17.
; A crank arm 99 is rotated by the motor 97 to move the flap
57 of the first valve means 53 via an actuating arm 101
pivotal connected at its ends to the crank arm 99 and the
flap 57. Operation of the crank arm 99 in either direction
by the motor 97 moves the flap 57 between its first and
second positions.
A connecting linkage 103 between the flaps 57 and
55 allows movement of the flap 57 by the motor 97 to Somali-
tonsil move the flap 55 between its first and second positions. The linkage 103 comprises a leading arm 105 fixed
at one end to the flap 57 near its outer edge 67, and a
following arm 107 pivotal mounted at one end to the flap
55 near its outer edge 65. The arms 105 and 107 extend
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toward each other to form a V-shaped linkage 103, and are
pivotal joined to each other at their other ends by a
pivot 109~ A brace arm 111 can be provided extending between
the flap 57 and leading arm 105.
Second and third means are provided for moving the
second and third valve means 71 and 73 between the first and
second positions. The second valve moving means 115 prefer-
ably comprise linkage means extending from the first valve
means 53 to the third valve means 73 to move the third valve
means simultaneously with movement of the first valve means 53.
The linkage means includes a first link 117 extending from
the first flap 55 adjacent its pivot mounting to the edge 87
of the first flap 83 of the third valve means 73. A second
link 119 connects the first flap 83 to the second flap 85 of
the third valve means 73. Movement of the flap 55 of the
first valve means 53 in one direction or the other will
move the flaps 83 and 85 of the third valve means 73 Somali-
tonsil in the same direction.
The third valve moving means 123 comprises linkage
means extending from the first valve means 53 to the second
valve means 71 to move the second valve means 71 simultaneously
with the movement of the first valve means 53. The linkage
means includes a third link 125 extending from the second flap
57 adjacent its pivot mounting to the edge 79 of the first
flap 75 of the second valve means 71. A fourth link 127
connects the first flap 75 to the second flap 77 of the
second valve means 71. Movement of the flap 57 of the first
valve means 53 in one direction of the other, will simulate-
nuzzle move the flaps 75 and 77 of the second valve means
71 in the same direction.
It will be seen that a single motor 97 is all
that is needed to move the first, second and third valve
means 53, 71 and 73 in the ducts 17, 19 and 21 respectively
and thus to adjust the amount of building air to be exhausted
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along with the amount of fresh air to be drawn in. As can
be understood, the valve means 53, 71 and 73 will usually be
located in an intermediate position, between the first and
second positions, as shown in Fig. 6, to provide both air
circulation and air changing.
In accordance with the invention, the motor of
the fan 47 and the motor 97 provided for moving the first,
second and third valve means 53, 71 and 73 are independently
controlled by a pair of air temperature sensors.
lo The first sensor (not shown) of this pair is
intended to be mounted inside the building at a remote
distance from the ventilating unit (for example 15 feet).
This first sensor is used exclusively for controlling the speed
of the fan 47 which is itself intended to continuously
operate under normal conditions. Assuming that the fan 47
is a two-speed fan and an average temperature of 75F is
desired in the building, the first sensor may be set at a
temperature slightly higher than the desired temperature,
let say 80F, to switch the fan 47 to high speed as soon as
the ambient temperature detected by the sensor becomes higher
than 80, and to switch it back to low speed as soon as the
ambient temperature moves down below 80F. The first sensor
may also be set to completely switch off the fan 47 and thus
stop the ventilation as soon as the ambient temperature
becomes lower than a predetermined value, like 65F.
Under normal conditions where the ambient temperature
inside the building is higher than the predetermined temperature
of 65F, the fan 47 therefore is operating continuously.
Switching of the fan from low to high speed occurs at the
preset value of 80F. At high speed, the fan 47 circulates
more air at higher speed and thus improves mixing and
distribution of building air and fresh air inside the
building.
Since the switching temperature preset in the sensor
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is slightly higher than the temperature actually desired in
the building, the fan 47 is mainly operating at low speed,
thereby making it less subject to failure in addition of
making the building more conformable to live in, with much
less draught.
The second temperature sensor of the pair of sensors
used for controlling the unit 1 is mounted inside the housing
3. This second sensor numbered 131 (see fig. 4) is prefer-
ably mounted on the intermediate partition 15 in such a
I manner that its probe 133 extends just behind the fan 47
to accurately measure the actual temperature of the building
air drawn into the exhaust duct 17.
This second sensor is used exclusively for control-
lying the respective positions of the valve means 53, 71 and 73
by suitable actuation of the motor 97 in one or the other way
via a control circuit 135 (see fig. 4). This control circuit,
may be designed to actuate the motor 97 proportionally to
the value and sign of the difference between the desired
temperature and the actual building temperature detected by
the sensor. However, the control circuit will preferably be
designed to incorporate a limiting circuit adjustable from
1 to 4F, to prevent the valve means from being continuously
and permanently adjusted.
In combination with the above described control
system, the ventilating unit 1 according to the invention
constitutes a completely balanced system capable of maintaining
a constant temperature inside a building provided that there
is sufficient heat. Tests carried out by the inventor in
a hog barn have proved that a temperature difference of
approximatevely 3F could easily be maintained even in the
coldest periods of the year.
Of course, numerous modifications and/or technical
additions can be made within the scope of the present invention
to the above described unit and system.
By way of example, spring means (not shown) can be
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employed to automatically open the valve means 53, 71 and 73
in the event of a power failure to allow ventilation.
Similarly, one or more air quality sensors (not
shown) such as a humidistat, may be incorporated into the
control system of the unit to provide positioning of the
valve means 53, 71 and 73 to obtain from the control of the
desired air circulation and/or amount of air change.
