OPERATION
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DK46 - DK800
www.krohne.com05/2019 - 4000430905 - AD DK46-800 Exi-II2G R06 en
5.3 Electrostatic charge
In variable area flowmeters, it is possible under field conditions for charge separation to occur in
the measuring tube due to the transport of non-conductive fluids and / or when the flow comes
into contact with non-conductive built-ins.
In glass devices, it is basically possible for the electrostatic field generated inside the measuring
tube to "punch through" to the outside of the device.
For that reason, variable area flowmeters need to be permanently grounded by the operator via
the process connections in order to allow discharge of electrostatic build-up.
The operator is also responsible for continuing the complete grounding of the process line.
If grounding cannot be made via the process connections, e.g. top and bottom fittings are made
of plastic, the flowmeter should be connected to the local ground potential via the connection to
ground. The connection only ensures electrostatic grounding of the device and does not comply
with the requirements of an equipotential bonding connection.
When dust-free gases or liquids are measured, the flow rate should not exceed 20 times the
nominal flow rate. The max. allowable operating pressure PS printed on the nameplate is to be
considered.
In order to avoid ignition hazards due to electrostatic charge, variable area flowmeters
may not be used in areas with:
• processes that generate strong charges,
• mechanical friction and cutting processes,
• spraying of electrons (e.g. in the vicinity of electrostatic painting systems) or
• pneumatically conveyed dust is exposed.
WARNING!
Electrostatic charging of the housing surface by friction must be avoided. The devices must not
be dry cleaned.
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