Lake Monitors Flow Transmitters - Manual (Page 19)

FILTRATION AND CONTAMINATION
Recommended Filtration
The manufacturer recommends system filtration of at least 74 micron
filter or a 200 mesh screen. It has been found that if inadequate filtration
has caused meter failure, it will normally fail in the open position. Some
systems may require a magnetic filter. IMPORTANT: Meter damage
caused by excessive contamination is not covered under warranty.
Stabilized Contamination
The goal of filtration is to create effective protection from system
contamination. Proper filtration stabilizes contamination to allow
fluid components to function properly. A fluid system is considered
stabilized when, “contamination in” equals “contamination out”.
Proper filtration must reduce initial contamination to a stabilized level
within an acceptable time period. the system should be stabilized in
time to prevent premature wear or damage to meter components.
Contamination Sources
Fresh Fluid
When fresh fluid is stored in holding tanks, it may be contaminated
with scale or metal flakes from inside the tank. To prevent this type of
contamination, be sure to filter fresh fluid before adding to the system.
New Machinery Contamination
When building new machines, a certain amount of built-in contamination
is unavoidable. Typical built-in contamination consists of dust, dirt,
chips, fibre, sand, flushing solutions, moisture, weld splatters and
pipe sealants. Flushing the system before operation can reduce
contamination, but cannot eliminate it totally. Unless the system is
flushed at a high velocity, some contamination will not be dislodged
until the system is in operation. System contamination can cause fluid
component malfunction.
Environmental Contamination
When performing routine maintenance, the system’s fluid is commonly
exposed to environmental contamination. Exercise caution during
routine maintenance to prevent this type of contamination. Be sure to
change breather filter and systems air filter regularly.
Page 19 / Flow Meters / Lake Manual