Manual FLOW 38 Page 16 (total 54) COMAC CAL s.r.o.
Electrodes
The electrode material must be selected according to chemical resistance to the liquid to be measured.
The purity of the electrodes may have an influence on measurement accuracy, their heavy foulness may
cause even the interruption of the measuring function (isolation from the liquid). It is not necessary to
clean the electrodes right after delivery before their installation in the pipeline. If the electrodes indicate
signs of foulness, clean them with a soft cloth or use a chemical cleaning agent. Mind damaging to the
lining! During routine operation, in case of a great majority of liquids, it is not necessary to clean the
flow meter for the entire operation period of the flow sensor; self-cleaning by flow of the liquid is
sufficient (recommended velocity is over 2 m/sec).
PTFE, PFA, EFTE lining
Meters with PTFE lining are equipped with protective covers to prevent the sealing surfaces from
damaging during transportation or storage and from changing the shape (due to elastic memory of the
PTFE material, it is restraightened to the tube). Protective covers may be removed only right before the
installation. If these covers are removed due to a check, it is necessary to replace them immediately.
Carry out the installation at the lowest point of the pipeline to avoid the occurrence of vacuum. Never
detach and damage the rim of the PTFE lining turned up to the of flow sensor faces. Remove the covers
from the inlet and outlet sides right before insertion of the sensor between the pipeline flanges and
replace them with metal plates (0.3...0.6 mm thick). After insertion of the sensor, remove the metal plates
and install the screws/bolts.
High temperature pipeline
High temperature medium
At temperatures of the medium to be measured over 100°C, it is necessary to compensate the forces
caused by thermal expansion of the pipeline due to its temperature rise. For short pipelines, it is necessary
to use flexible seals, for long pipelines, use flexible pipe elements (e.g. bends).
The flow sensor must never by thermally insulated. In case that the sensor is placed in a thermally
insulated pipeline, the thermal insulation must be interrupted and the flow sensor is installed without
thermal insulation.
When a compact meter is used (evaluation unit placed on the sensor body), it is necessary to respect the
temperature of medium up to 90 °C. In case of exceeding this temperature, the correct functionality of
the electronic evaluation unit is not guaranteed, or there is a risk of its destruction.
Installation check
After installation of the flow sensor in the pipeline, the following must be checked:
- According to the name plate, if there is a relevant meter in the given measuring point (pressure,
temperature, dimension, etc.).
- If the direction of the arrow on the device is in agreement with the direction of the flow in the
pipeline.
- Correct position of the measuring electrodes (horizontally).
- Correct position of the electrode for empty pipeline detection (up).
- If all bolts (screws) are tightened properly.
- If earthing rings are used, then their correct installation and connection with the sensor.
- Accuracy of flow sensor earthing.
- Accuracy of execution of the pipeline calming section lengths
- If the sensor is protected against vibrations and mechanical damage.
- If the name plate (serial number) on the sensor corresponds to the one on the electronics.
To Next Page
Loading...
Need help?
General