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Wire Cloth and Screen Trays
Check condition of wire cloth and screen trays both before
and after each operation�
Wire Cloth
Testing grade wire cloth is a precision-made material and
should be treated with care. The ASTM E11 specification
permits only very slight variations in average opening and
wire diameter of testing grade wire cloth� Abrasion due to
normal use and/or improper cleaning and handling can
cause the wire cloth to be out of specification to a consid-
erable degree before it appears so� Check the wire cloth
periodically for conformance to specifications.
Wire cloth may eventually sag, reducing its effective
screening area� Wire with 1/4in and coarser openings is
rigid and self-supporting. No.5 and finer sizes have hooked
edges which interlock with the tray's side clamps to provide
tension adjustment. Trays with No.16 and finer wire cloth
have wire cloth support strips to minimize wear and dis-
tortion� Backup wire cloth can be furnished as an option at
extra cost, if additional support is desired� Tray side clamps
for hooked edge wire and flat wire are NOT interchange-
able�
Screen Trays
The life of your screen trays can be prolonged by establish-
ing good procedures for handling and storing trays� Avoid
bumping or bending the corners of the tray flanges.
Bent flanges "work" during operation of the machine and
will eventually break�
Troubleshooting
WARNING:
Disconnect power supply before
servicing or cleaning.
WARNING:
DO NOT plug in or operate the
Testing Screen without all covers installed.
Noisy Operation
Loud knocking during operation often indicates worn con-
necting rods, rod bearings, or the wristpin assembly� See
Drive Assembly on
page
Testing Screen Shuts Off
If either the Testing Screen or its motor is overloaded, a
circuit breaker in the switch could disconnect� If the ma-
chine stops during a test, check the switch� If the red button
extends halfway out, the circuit breaker has tripped� Check
to see that you have sufficient voltage to the machine. If so,
check to see if your sample is too large�
To reset, push the red button all the way in, then push the
green button to restart�
Shifting of Materials
An imbalance or out-of-level vibration can cause shifting of
material to the sides or corners of trays, decreasing screen-
ing efficiency. Such shifting is likely to be intermittent,
especially on a new screen� Run the machine empty for
half an hour before making drastic changes — the problem
may disappear of its own accord� If shifting persists, check
the foundation to be sure that all mounting bolts are equally
tight� Check also the bottom-to-case bolts�
Tighten mounting bolts on the side to which material is
moving� Loosen the opposite side slightly�
Look for bent tray edges and material trapped between
vibrating sections� Worn guide bearings, wristpins, and/
or connecting rods also cause shifting of material� Refer to
sections on the maintenance of those parts�
Sample material will also shift if the unit is not properly lev-
elled� The internal vibrating assembly will not work properly
in a machine that is out of level� See Installation on
If the case is seriously out of level compared to the vibrat-
ing assembly, look for worn or misaligned parts�
Sluggish Start-Up or Operation
Check loads on sample trays and total sample weights�
See Sample Capacity on
Inspect V-belts for wear, tension and alignment� Check
pulleys for alignment� See Drive Assembly on
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