Richter LPV/F Series Low-Pressure Safety Valves - Manual (Page 12)

Series LPV-A/F, LPV-D/F
Seite 12
9530-060-en Revision 01
TM 7464 Edition 02/2009
8 Malfunctions
• Safety valve is leaking
Is there foreign matter between the seat and
plug?
Is there any wear or damage to the seat or plug?
If so, it is necessary to rework the sealing
surfaces of the seat and plug or replace these
components.
• The valve stroke is not reached.
Check of dimensions as per dimensional drawing
required. See Section 10.
• Medium is escaping at the bonnet
Are the screws 901/1 and 902/2 tightened with
hex. nuts 920/2?
Check tightening torques of the bonnet screws
with a torque wrench!
If the leak continues, the recommended tightening
torques may be exceeded by 10%.
If the leak-free state cannot be achieved even after
tightening the screws, the plastic lining is
damaged.
Dismantle the valve and have it repaired.
• Flange connection ball valve/pipe is leaking
Check the torque of the pipe screws with a torque
wrench. (See Section 1.4). If tightness is not
achieved, the recommended torque may be
exceeded by 10%.
If it still proves impossible to stop the leak, then the
lining is damaged. Dismantle the valve and check.
9 Maintenance
Low-pressure safety valves must be
checked for operability at regular intervals
according to the national regulations (in
Germany: UVV - pressure vessels, VBG 17
§ 32 and TRD 601 sheet 2, paragraph 3.4).
The intervals for regular checks are to be laid
down by the customer in line with the operating
conditions.
The operability is checked in the dismantled state
on a suitable test bed.
All repair work is to be performed by qualified
personnel using the appropriate tools.
For the arrangement, designation and item
numbers of all parts of the valve, see Section 10.
Spare parts are to be ordered with all the details in
acc. with the valve identification.
Only original spare parts may be installed.
9.1 Screw connections
To prevent leaks, a regular check of the
connection screws should be made in line with the
operating requirements.
For tightening torques, see Section 1.4.
To prevent screw connections from becoming
loose in the event of pressure fluctuations or plant
vibrations, we recommend the installation of
expansion joints or pulsation dampers.
9.2 Cleaning
Prior to starting any repair work, the valve is
to be thoroughly cleaned. Even if the valve
has been properly emptied and rinsed,
residual medium may still be found in the valve, e.g.
between the lining and body or in the bonnet.
Plastic parts may absorb medium which gradually
emerges from the material after cleaning.
Wear the prescribed protective clothing!
Low-pressure safety valves which have been cleaned
with water or other media must be dried before re-
assembly of the parts and installation of the valve in
the plant.
9.3 Modification of the low-
pressure safety valve
If modifications to the valve are required, the
manufacturer must always be consulted.
Examples: Conversion to changed test gauge
pressure, replacement of the weights.
After
approval by the manufacturer, these
modifications can be performed either by the
manufacturer or by the customer under the guidance
of a technical supervisory agency or any other
approval authority.