Richter HVR Series Bellows-Sealed Valves - Manual (Page 9)

Installation and Operating Manual
Series HV, HVR
9520-050-en Revision 01
TM 6128 MPE/Wm Page 9 Edition 04/2005
6 Operation
6.1 Initial commissioning
Normally, the globe shut-off valves have been tested
for leaks with air or water. Prior to initial operation
check cover screws. For torques see Section 1.3.
Unless otherwise agreed, there could be
residual amounts of water in the flow
section of the ball valve; this could result in
a possible reaction with the medium.
To prevent leaks, all connection screws should be
retightened after the initial loading of the valve with
operating pressure and operating temperature. For
torques, see Section 1.3.
6.2 Inadmissible modes of opera-
tion and their consequences
Crystallisation may result in damage to the seat
rings or ball/stem unit. This can be prevented by
heating.
In extreme cases this may cause blocking.
When used in the minus temperature range, the
regulations applicable in the country in question
must be observed.
Operation with solids leads to increased wear.
Operating during cavitation leads to increased
wear.
Non-observance of the pressure-temperature
diagram can lead to damage.
Do not subject the handwheel to heavy loads; the
lever or valve may be damaged.
6.3 Shutdown
The local regulations are to be observed when
dismantling the valve.
Prior to undoing the flange connection ensure, that
the plant is depressurised and emtied.
Prior to starting any repair work, the valve
is to be thoroughly cleaned. Even if the
valve has been properly emtied and rinsed,
residual medium may still be found in the valve,
After dismantling, immediately protect the valve
flanges against mechanical damage with flange
caps. See also Section 5.1.
7 Malfunctions
Flange connection valve/pipe is leaking
Retighten the flange screws to a tightening torque
according to Section 1.3. If this does not remedy
the leak, the recommended torques may be ex-
ceeded by 10%.
If this also fails to stop the leak, dismantle and
inspect the ball valve.
Flange connection main body/cover is leaking
Retighten cover screws. See paragraph "Flange
connection valve/pipe is leaking".
Packing is leaking
Retighten packing nuts in line with the details in
Section1.3.
Disadvantages:
The medium can destroy the metallic internals
relatively quickly.
The hysteresis can be impaired.
Replace bellows.
Alarm connection reports a rise in pressure or a
leak.
Replace bellows.
Replace plug and/or seat.
Replace packing rings.
Valve can only be moved with difficulty.
Is the stuffing box tightened too much?
Valve does not seal tight.
Are there solids between the seat and plug?
Are the sealing surfaces of the seat or plug dam-
aged?
The flow rate is too high or too low.
The performance curve is not correct.
The valve cavitates.
Do the rated data according to the data sheet or
works certificate match the data of the plant?
Are the correct seat and plug installed? See mark-
ings on the seat and plug and compare them with
the name plate and the data sheet.