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The.Porta-Screen®.will.not.clamp.or.operate.properly.un-
less.fully.loaded.with.trays..If.your.test.requires.fewer.trays.
than.the.capacity.of.the.Porta-Screen®,.you.may.insert.the.
required.trays.in.the.upper.slots.with.the.pan.immediately.
below..Then.fill.the.lower.slots.with.extra.trays.
3.. Clamp.the.trays.by.rotating.the.clamp.levers.so.that.they.
point.down.
4.. Pour. your. sample. into. the. top. tray.. Refer. to. the. sample.
capacity.information.and.be.sure.not.to.overload.the.Por-
ta-Screen®.
5.. Connect. the. three-pronged. plug. into. a. properly-wired,.
grounded.receptacle.with.appropriate.electrical.current.
6.. Set.and.activate.the.timer.
7.. When. the. machine. stops,. unclamp. the. trays. by. rotating.
the.clamp.levers.so.they.point.up...Remove.and.empty.the.
trays,.following.the.directions.in.the.test.specifications.
8.. When.you.have.finished.the.test,.unplug.the.machine...Do.
not. reconnect. power. until. you. are. ready. to. use. the. ma-
chine.again.
9.. Store. clean,. empty. trays. in. the. unit,. leaving. them. un-
clamped.
10.. Re-level.the.machine.before.the.next.use.
3.0 SAMPLE CAPACITY
Capacity.of.the.Porta-Screen®.depends.on.the.specifications.
of.the.test.and.the.type.and.size.of.the.material.being.tested..
For.any.given.sample,.the.Porta-Screen's.maximum.capacity.
is.determined.by.the.tray.which.has.the.largest.load.at.the.end.
of.the.test..This.is.the.limiting.tray.
3.1 COARSE AGGREGATE
Minimum. quantity. of. sample. is. usually. established. by. the.
specifications. of. the. test. procedure.. . For. example,. ASTM.
C136. "Specification. for. the. Sieve. or. Screen. Analysis. of. Fine.
and.Coarse.Aggregates".calls.for.the.minimum.weight.of.the.
test.sample.of.coarse.aggregates.(density.such.as.limestone.
or.gravel).as.follows:
These. guidelines. on. minimum. sample. size. quantities. are.
.
for. representative. samples.. Always. take. a. much. larger.
amount,. perhaps. from. several. spots. in. a. storage. bin. or.
stockpile.. Then. combine. and. reduce. them. to. the. correct.
quantity.by.splitting..
With.coarse.series.trays.(2in–No.4),.the.limiting.tray.should.
.
have.no.more.than.one.layer.of.particles.over.the.wire.cloth.
at.the.end.of.the.test..Therefore,.lightweight.aggregates.or.
coal.must.be.tested.in.lower.sample.weights..High-density.
ores.or.pellets.may.be.tested.in.larger.amounts.by.weight..
Many. light. materials. are. also. soft,. and. test. times. should.
be.limited.to.avoid.degradation.of.the.sample.
Most. samples. of. up. to. 2in. topsize. can. be. handled. in. a.
.
single.batch.without.difficulty..We.do.not.recommend.the.
use.of.trays.with.mesh.sizes.above.1.5in,.since.larger.par-
ticles.become.wedged.in.the.mesh.and.make.it.difficult.to.
remove.the.trays.
Gilson's Porta-Screen
®
Normal Maximum
Size of Particle
mm (in)
9.5 (3/8)
12.5 (1/2)
19.0 (3/4)
25.0 (1)
38.0 (1.5)
50 (2)
63.5 (2.5)
3.2 FINE AGGREGATES
With.fine.series.trays.(No.8–200),.the.limiting.tray.should.con-
tain.no.more.than.approximately.4g.per.square.inch.of.sieve.
surface. at. the. end. of. a. test.. Assuming. that. the. material. is.
about. the. density. of. sand,. there. will. be. approximately. 800g.
maximum.on.the.limiting.tray.
Since. the. Porta-Screen®. is. designed. primarily. for. use. in. the.
2in–No.20.range,.separations.in.finer.sizes.will.not.be.as.pre-
cise..If.you.are.testing.materials.exclusively.in.the.fine.range,.
we.recommend.equipment.specifically.designed.for.this.pur-
pose,.such.as.the.SS-8R.Gilson.8in.Tapping.Sieve.Shaker.
4.0 MAINTENANCE & DISASSEMBLY
NOTE: Please read and understand all safety and main-
tenance instructions for the Gilson Porta-Screen® before
performing maintenance on it.
WARNING
Always disconnect and lock out electric power
before performing maintenance!
4.1 CLAMPING SYSTEM
1.. DISCONNECT.AND.LOCK.OUT.ELECTRIC.POWER.
2.. Load.the.Porta-Screen®.with.trays.and.a.pan,.filling.all.the.
slots.
3.. Rotate.the.Clamp.Levers.(38).so.that.they.point.down.
4.. Locate. the. Clamp. Adjusting. Nuts. (9),. which. are. on. the.
lower.ends.of.the.four.Clamp.Tension.Rods.(7).
5.. Tighten. the. nuts. only. enough. to. prevent. the. trays. from.
rattling.when.the.machine.is.operating.
4.2 LUBRICATION
1.. DISCONNECT.AND.LOCK.OUT.ELECTRIC.POWER.
2.. Remove.and.set.aside.trays.and.a.pan.
3.. Remove.upper.case.cover.
4.. Connection Rod Bearing: Lubricate.the.Connecting.Rod.
Bearing.(52).after.every.80–100.hours.of.operation.
Minimum
Sample Weight
kg (lb)
1 (2)
2 (4)
5 (11)
10 (22)
15 (33)
20 (44)
35 (77)
5
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