Richter GU/F Series Overflow Valves - Manual (Page 7)

Series GU/F
Page 7
9530-070-en Revision 00
TM 6908 Edition 10/2007
A difference is made between two cases for the use of
chargeable liquids (conductivity <10
-8 S/m):
1. Chargeable liquid and non-conductive
lining
Charges can occur on the lining surface. As a
result, this can produce discharges inside the
valve. However, these discharges cannot cause
ignitions if the valve is completely filled with
medium.
If the valve is not completely filled with medium,
e.g. during evacuation and filling, the formation of
an explosive atmosphere must be prevented, e.g.
by superimposing a layer of nitrogen.
It is recommended to wait 1 hour before removing
the valve from the plant in order to permit the
elimination of static peak charges.
This means that, to safely prevent ignitions, the
valve must be completely filled with medium at all
times or else a potentially explosive atmosphere
must be excluded by superimposing a layer of inert
gas.
2. Chargeable liquid and conductive lining
No hazardous charges can occur as charges are
discharged direct via the lining and shell (surface
resistance
<10 9 Ohm, leakage resistance <10 6
Ohm).
The following special feature applies to the series
with bellows (HV, HVR, BAV, KSE, KSEA, GU,
GUT, PA):
The bellows are not offered in a conductive
version, i.e. the restrictions under point 1. apply.
Richter optionally offers conductive metallic
bellows for the series HV.
Static discharges of non-conductive linings are
only produced through the interaction with a
non-conductive medium and are therefore the
responsibility of the plant operator.
Static discharges are not sources of ignition
which stem from the valves themselves!
The temperature of the medium must not exceed
the temperature of the corresponding temperature
class or the maximum admissible medium
temperature as per the operating manual.
If the valve is heated (e.g. heating jacket), it must
be ensured that the temperature classes
prescribed in the Annex are observed.
To achieve safe and reliable operation, it must be
ensured in inspections at regular intervals that the
valve is properly serviced and kept in technically
perfect order.
Increased wear to the valve can be expected with
the conveyance of liquids containing abrasive
constituents. The inspection intervals are to be
reduced compared with the usual times.
Actuators and electric peripherals, such as
temperature, pressure and flow sensors etc., must
comply with the valid safety requirements and
explosion protection provisions.
The valve must be grounded.
This can be achieved in the simplest way via the
pipe screws using tooth lock washers.
Otherwise grounding must be ensured by other
action, e.g. cable bridges.
Plastic-lined valves must not be operated with
carbon disulphide.
4 Safety note for valves, certified to Clean Air Act (TA Luft)
On request, this valve can be supplied compliant with
the German Clean Air Code.
Certificate / Manufacturer Declaration Validity is
dependent on the operating instructions being read
and observed. In particular, servicing must be conducted at regular
intervals, and the bolted connections relevant for
tightness must be inspected and retightened if
necessary.