4220 Flow Meter
Section 6 Maintenance and Service
6-4
Note
Regeneration of the desiccators is extremely important.
Saturated desiccators let the flow meter draw moisture inside,
exposing both mechanical and electronic components to water
and/or chemical contamination. The air in many installations
contains fumes that will form acids in the presence of moisture.
These acids may corrode electrical components, particularly
connectors and circuit boards.
Moisture drawn into the submerged probe’s reference port
vent tube will disable the probe.
Unseen damage caused by moisture will eventually ruin the
flow meter. For maximum equipment life and reliability, inspect
the desiccators regularly and regenerate them when neces-
sary.
6.3 Care of the Submerged Probe and Cables
The submerged probe and its cable require little periodic mainte-
nance unless there is a great deal of debris in your flow stream.
Certain materials that swell when wet, such as sawdust, can clog
the ports of the probe blocking the hydrostatic pressure of the
stream from reaching the transducer. The submerged probe
pressure transducer is in a stainless steel housing filled with sil-
icone oil.
The transducer is directly behind a thin stainless steel dia-
phragm that faces the nose section of the probe. If you remove
the nose section from the submerged probe to clean it, this dia-
phragm will be exposed. Read the following sections carefully
before attempting to disassemble the probe.
CAUTION
If you disassemble the submerged probe for cleaning, do not
touch the stainless steel diaphragm with your fingers or tools.
The diaphragm is very thin (<0.003"), and easily bent.
The slightest deformation may result in damage to the trans-
ducer or the placing of a permanent offset on it. In either case
the submerged probe will be ruined. Do not drop the assembly
or subject it to any physical abuse.
6.3.1 Low Maintenance The submerged probe contains no user-serviceable parts and nor-
mally requires no maintenance. The probe will continue to
function even when covered with several inches of silt, sand, or
other solid materials. It is generally not necessary to clean accu-
mulated solid materials from the vicinity of the probe.
However, it may be beneficial to periodically clean the flow
stream up- and downstream from the submerged probe to
maintain the hydrostatic conditions on which the level-to-flow
rate conversion is based. The probe has been designed to expose a
small frontal area and a streamlined profile to the flow, and that
reduces the possibility of accumulating deposits of solid mate-
rials.