Richter GU/F Series Overflow Valves - Manual (Page 14)

Series GU/F
Page 14
9530-070-en Revision 00
TM 6908 Edition 10/2007
9.3 Modification of the overflow
valve
If modifications to the valve are required, the
manufacturer must always be consulted.
Examples: Modification with changed test pressure,
replacement of the spring or adaption to the mass flow
by reducing the travel.
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.
9.4 Adjustment of the test
pressure
Undo locking plate 539, dismantle lifting lever 238
and unscrew the lifting cap 535.
Undo nut 920/3.
Adjust the spring tension with the adjusting screw
538 to the specified test pressure.
Counter adjusting screw 538 with a hex. thin nut
920/3 resp. with centering nut 555 (DN 25).
Check test pressure.
Screw on lifting cap 535 and tighten.
Insert lifting lever 238.
Mount locking plate 539.
Have the valve lead-sealed.
The data specified in the test certificates are to be
observed.
9.5 Important notes on
dismantling / installation
First relieve the plug 204!
Then undo the screws between the bonnet 513
and body 100.
The seat and plug could otherwise be destroyed.
Read the precise instructions in Section 9.6.
Always replace the seat and plug pairwise and
always rework them completely.
Reworking of the seat and plug requires
specialised knowledge of the material as well as
special lapping wheels.
It is therefore recommended to have this work
carried out by the manufacturer.
After dismantling, check all parts for wear and
damage.
Observe sectional drawings in Section 10.
9.6 Replacement of components
9.6.1 Dismantling of the plug
Undo locking plate 539, dismantle lifting lever 238
and unscrew lifting cap 535.
Mark the position of the stem nut 534.
Unscrew the self-locking hex. nut 929/1 and stem
nut 534 off the stem 802.
When undoing or tightening the hex. nut, hold the
stem tight with a pair of pliers.
Do not turn the entire stem 802! There is a
risk of the insert sleeve 308 being
unscrewed out of the bellows 206 or the
folds being damaged!
Mount a suitable distance sleeve (not included in
the scope of delivery) over the stem 802.
Screw the stem nut 534 against the distance
sleeve. The plug 204 is lifted off the seat 205 and
the closing force becomes ineffective.
Loosen the bolts 901/1, 936/1, 936/2 and 920/2
from body 100 and spring bonnet 513 and lift the
spring bonnet with internals completely off.
Grip the bellows 206 in the reinforced section just
above the lifting aid 237. Unscrew the lifting aid off
the bellows and remove the plug 204.
9.6.2 Dismantling of the seat
Remove spring bonnet 513 from the body 100.
See Section 9.6.1.
Unscrew seat 205 from the body 100 with a special
wrench. See Section 1.4.
9.6.3 Installation of the seat
Centre the new or reworked seat 205 in the body
100.
First tighten the attachment nuts 920/1 hand-tight
and then with a torque wrench evenly and in
diametrically opposite sequence.
9.6.4 Installation of the plug
All parts are to be thoroughly cleaned before
assembly.
Centre the new or reworked plug 204 in the lifting
aid 237 and screw completely onto the thread of
the bellows hand-tight.
Counter the bellows 206 on the reinforced section
with a pair of pliers.