Twin City Modular Plenum Fans - MPLFN / MPLFS / MPLQN / MPLQS - IM-495 - Manual (Page 2)

2 Twin City IM-495
Storage Procedure. –. Fans. should. be. stored. indoors.
whenever. possible. where. control. over. temperature,.
shock.and.dust.is.reasonably.maintained..If.units.are.to.
be.stored.outside.in.the.elements,.they.should.be.cov-
ered. with. a. water-resistant. material.. Stored. equipment.
should. be. stored. on. a. clean,. dry. floor. or. blocked. up.
off.the.ground.on.blocks.to.prevent.unit.from.setting.in.
any.water.or.directly.on.the.ground..If.shock.or.vibration.
will.be.present.during.storage,.the.unit.may.need.to.be.
placed. on. some. type. of. vibration. dampening. material.
to.aid.in.preventing.brinelling.of.the.bearing.surfaces.
Periodic Check.–.On.a.monthly.interval,.the.equipment.
should. be. checked. to. ensure. that. it. has. remained. in.
an.acceptable.stored.condition..After.verifying.the.fan.is.
disconnected. from. the. electrical. supply,. the. fan. wheel.
should. be. rotated. several. times. by. hand. while. adding.
enough. grease. to. replenish. the. bearing. surfaces. with.
fresh.grease.and.to.maintain.a.full.bearing.cavity..Grease.
used.must.be.compatible.with.that.already.supplied.in.
the. motor. and. fan. bearings.. The. fan. impeller. should.
be. left. at. approximately. 180. degrees. from. that. of. the.
previous.month.to.prevent.the.shaft.and.impeller.from.
taking. a. set. in. one. position.. Storage. records. should.
be. maintained. which. indicate. the. above. requirements.
have.been.followed..Consult.the.motor.manufacturer.for.
proper.storage,.space.heater.connection.and.lubrication.
if.the.unit.was.supplied.with.one.
Start-Up.–.When.the.unit.is.removed.from.storage,.all.
bearing.grease.should.be.purged.and.replenished.with.
fresh. grease. as. per. the. lubrication. decal.. The. motor.
resistance.should.be.measured.to.verify.it.is.still.at.a.
satisfactory.level.compared.to.the.value.recorded.prior.
to.storage.
Foundations and Supporting Structures
Floor.mounted.fans.should.be.installed.on.a.flat,.level.
surface. with. sufficient. structure. support.. Support. shall.
be.suitable.for.static.and.dynamic.loads.and.foundation.
frequencies. be. separated. at. least. 20%. from. the. rota-
tional.speed/speed.ranges.
If. the. fans. are. mounted. in. a. structure,. the. support.
should. be. placed. under. the. enclosure. inlet. and. outlet.
edges. as. a. minimum.. The. fan. mounting. surfaces. or.
beams. must. be. flat. and. level.. Structural. resonance.
should.be.at.least.20%.from.the.fan.operating.speed,.
when.considering.the.weight.of.all.fans.and.accessories..
Any. ducting. and/or. dampers. with. sleeves. should. have.
independent. support;. do. not. use. the. fan. for. support..
Isolating. the. fan. from. ductwork. with. flex. connections.
eliminates.transmission.of.vibration.
1..Sufficient. structure. must. be. provided. to. support.
weight.of.fan.assembly.
2..Sufficient. restraint. must. be. provided. to. resist. the.
pressure. force. against. the. fans.. Typically. fans. are.
assembled.in.an.application.in.a.modular.fashion.with.
multiple.fans.working.in.parallel..The.cumulative.thrust.
force.must.be.restrained.to.prevent.the.fan.assemblies.
from.leaning.or.tipping.forward..The.force.acting.on.
the.fan.assemblies.is.calculated.as.shown.below.
. Thrust.force.(lb
f
).=.H.x.W.x.N.x.P s
. 27.68
. Where
. P
s
..=.Maximum.operating.static.pressure.(in..w.g.)
. W..=.Width.of.each.individual.fan.(in.)
. H. =.Height.of.each.individual.fan.(in.)
. N. =.Quantity.of.fans.in.system
. 27.68.=.conversion.factor.for.in..w.g..to.PSI
. Example
. Parallel.fan.system.employing.nine.(9).–.Size.182.fans.
in.a.3.x.3.configuration..(3.fans.high.x.3.fans.wide)
. System.pressure.is.5.inches.of.water.column.
. Outside.dimension.of.fan.housing.=.approx..38.in..by.
38.in.
. Thrust.force.(lb
f
).=.H.x.W.x.N.x.P
s
. 27.68
. Thrust.force.(lb
f
).=.38.x.38.x.9.x.5.=.2348.(lb
f
)
. 27.68
. NOTE: . The. thrust. force. is. distributed. evenly. across.
the.front.surface.of.the.parallel.fan.system.
3..Recommend.attachments.to.the.sides.and.top.of.the.
parallel.fan.system.incorporating.some.form.of.spring.
support,.i.e..rubber.snubbers/isolators.or.springs..Such.
devices.should.be.attached.to.prevent.significant.point.
loading.on.an.individual.fan..They.should.be.located.
on.the.side.of.the.parallel.fan.system.at.the.top.cor-
ner.and.along.the.top.every.2.fans.or.less.
a..When.the.fans.are.rigidly.mounted.to.the.base,.an.
assumption. can. be. made. that. half. of. the. thrust.
load.will.be.supported.at.the.base,.and.the.sup-
ports.added.at.the.top.of.the.fan.need.to.carry.a.
minimum.of.one.half.of.the.thrust.load.
b..When.the.fans.are.supported.on.an.isolation.base.
or. isolators,. it. will. be. necessary. to. add. thrust.
restraints.around.the.periphery.of.the.fan.assembly.
to. support. the. entire. thrust. load.. Flex. connec-
tions.are.required.when.using.isolators.or.isolation.
base.
c..Attachments.to.the.fan.can.be.made.utilizing.the.
factory.mounting.holes..Recommend.that.the.gage.
of.the.materials.be.checked.for.tear.out.strength.
in. thrust. applications.. If. necessary. utilize. multiple.
mounting.hole.locations.to.distribute.the.load.