Series PA/F, PA/S
Page
7
9510-010-en
Revision 18
TM 9549
Edition 11/2018
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.
b) Discharges outside the valve
At the points where the non-conductive lining e.g.
protrudes on the sealing surfaces to the outside or
gets contact with the atmosphere on the outside, it
may lead to discharges from the lining to nearby
valves or attachments.
To safely avoid explosion hazards and accidents,
therefore, the atmosphere surrounding the valve
must not be explosive.
2. Chargeable liquid and conductive lining
No hazardous charges can occur as charges are
discharged direct via the lining and shell (surface re-
sistance <10
9
Ohm, leakage resistance <10
6
Ohm).
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 tempera-
ture 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.
♦
For safe and reliable operation, it must be ensured
with regular inspection intervals that the unit is
properly serviced and kept in a perfect technical
condition.
♦
Increased wear to the valve can be expected with
the conveyance of liquids containing abrasive con-
stituents. The inspection intervals are to be reduced
compared with the usual times.
♦
Actuators and electric peripherals, such as temper-
ature, 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 different
measures e.g. a cable link.
♦
Attachments such as actuators, position controllers,
limit switches etc. must satisfy the relevant safety
regulations as regards explosion protection and, if
required, be designed in compliance with ATEX.
♦
Special attention must be paid to the appropriate
safety and explosion protection notes in the respec-
tive operating manuals.
♦
Plastic-lined valves must not be operated with car-
bon disulphide.
4
Safety note for valves, certified to Clean Air Act (TA Luft)
Certificate / Manufacturer Declaration Validity is de-
pendent on the operating instructions being read and
observed.
♦
Carry out regular maintenance intervals and check
the tightness of the screw connections and tighten
as necessary.
