MECHANICAL
VENTILATION
Part 2 of 3
Eileen Wheeler
Assistant Professor
Environmental Control
Agricultural and
Biological Engineering
Fast inlet air velocity is essen
tial for providing air mixing and
desirable circulation patterns.
The basics of mechanical venti
lation are that fans exhaust air
from a building and thus create a
static pressure difference between
the interior of the building and
outside conditions (Figure 1).
Fans provide air exchange by
exhausting stale air. The very
slight static pressure difference
created by the exhaust fan causes
air to move into the building
through any opening. Air inlets
are designed and located in the
structure to supply air at a desir
able direction, speed, and condi-
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cnmo mm cm mu Dm
Wednesday. September 1
PAULS. ZIMMER
EPHRATA, PA
NORTHt
GARDEN SPOT ROAD
EPHRATA
ATTEND ONE OR BOTH
PLOTS FOR YOUR
ENJOYMENTAND
KNOWLEDGE!
THE FOLLOWING
COMPANIES WILL BE
REPRESENTED TO
DISCUSS YOUR SEED,
FERTILIZER AND
PESTICIDE NEEDS:
AGR EVO (LIBERTY LINK)
CIBA
ZENECA
DOW ELANCO
MONSANTO
a rrr.r. gift tot: r.Yr.rfroxr. |
Chemgro
BOX2IB ;
East Petersburg, PA 17520 ★
(717) 569-3296 *
(800) 346-4769 *
(GROW) *
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JN
Sei
tion. Properly functioning inlets
alleviate problems such as poor
air distribution, uneven tempera
tures, and drafts.
Functions of an air inlet:
1. Provide fresh air throughout
the building.
Control
2.
flow
3. Maintain fast inlet air veloc
ity.
Provide Fresh Air
Throughout The Building
Since birds are in all parts of
the building, then fresh air is
needed in all parts. Therefore, it is
necessary to have inlets in all lo
cations, or a distribution mecha
nism to get air to places where
there are no inlets.
Two methods commonly used
to do this are either by providing
inlets around most of the building
perimeter, such as along the long
sidewalls, or by bringing air in at
one point and distributing it
throughout the building using' a
duct (which is uncommon in the
10:00 AM-2:00 PM
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;ds
poultry industry).
Air moving through high
density poultry facilities picks up
moisture, odors, heat, ammonia,
and dust which we want to remove
from the house. Generally, air
near the inlet is fresher than air
near the exhaust fans In addition,
air movement near the inlets is
more predictable and less prone to
dead air zones than near the fans,
where the inlet’s control over air
direction has been dissipated
Inlets usually direct fresh air
flow horizontally along a ceiling
Inlet air jets have an affinity for
traveling along surfaces. In fact,
an inlet air jet that can attach it
self to a surface will travel farther
across a room than a free air jet
issued into free space.
One goal of inlet direction is to
cause cold air to mix with the air
already m the room before it en
ters areas where the birds are lo
cated In contrast, during hot
summer conditions, it is often de-
direction of air
sirable to have air moving over
birds as a breeze to enhance con
vective cooling. Inlets can direct
air onto the birds. Changing the
size and orientation of the inlet
opening or the type of inlet al
burn to P«fl« A 46)
CLARENCE KEENER JR,
MANHEIM, PA
JUNCTION
AUCTION ROAD
LANDISVIUE ROAD
COME LEARN ABOUT *
THE LATEST IN SEED J
HYBRIDS , VARIETIES 2
AND RESEARCH J
A .FEATURING:. . *
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FORAGE & PASTURE MIXES
SEQUENTIAL MATURITY
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Chemgro
Direction Of Air Flow Is
Controlled By The Inlet
itember 11th
MANHEIM
SOUTH |
BT CORN
FIGURE 1 A ventilation system includes fans inlets controls sensors and often
building insulation for proper environmental control
FIGURE 2 With in inlet adjusted correctly high-velocity cool air sweeps the ceiling and
mixes with warmer room air
TWO TOP RURITAN CLUB SHOW
STEAM & GAS, FLEA MARKET & CRAFTS
5 miles S. of Mercersburg, on PA 75 S. Two-Top Road
The Fast Growing Show of the East The Show with a SMILE
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Plaques will be given & other awards will be given Sunday
SEPTEMBER 19, 20, 21, 1997
Featuring
International Harvester H V|
FOR INFO CONTACT:
Ralph E. Rubeck 717-597-3672, %
Richard Martin 717-328-5655
FLEA MARKET & CRAFTS
Contact: Sam Bricker 717-328-9082,
Saturday Night
at 7 o’clock
Country Music
New Country
ALL NEW TRACK FOR THE FIRST TIME
TRACTOR PULLS, FARM STOCK
Parade of Equipment 12:30 Daily;
Sunday School at 9:00 a.m.
STREET TRUCK PULLS - FRI. EVE. 7 PM
Classes: 5,000 lb., 6,000 lb., and 6,500 open
TRACTOR PULL • SAT. AFTERNOON 1:30 PM
Classes: 4,000 to 15,500 lb.
Threshing w/Steam, Daily Events including sawmilling,
shingle mills, band saws, gas & steam engines, horse drawn
equipment, horse drawn wagon rides, parade of equipment,
craft demos, broom, corn meal, chair caning, pedal pull,
corn shell'ng, tractor & gas engines, & more
250+ crafts & flea market tp choose from.
Homemade food-second to none. Breakfast at 7 each day
Chicken, Country Ham, Hot Sausage, Fries, Ice Cream & Full
Lancastef ‘Farming' Saturday,"September IW7-M5
11th ANNIVERSARY SHOW
Featuring 1H
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ihaust
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isure
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hrow
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Bring your
tractor or
equipment
for a great plaque