FORM 119-ING. 04/11
We reserve to modify our production without previous communication
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30000 SERIES SAFETY VALVES
Safety valves 30000 Series, designed and manufactured by Technical s.r.l. in accordance with API 526, are full
nozzle and total lift type. They posses a high discharge coefficient (k=0.94), certified by I.S.P.E.S.L. and (K=0.951)
certified da ASME/NATIONAL BOARD on the basis of experimental tests performed by authorized laboratories; are
suitable for gaseous and liquid fluids.
The body and the bonnet are made from casting. The bonnet contains the spiral spring that, depending on the use
and type of fluid, can be assembled with closed cap or with open bonnet (vapour).
The seat is plane and “ metal on metal” type; it is possible to add valves with a soft sealing ring (FPM rubber). Upon
request, the valve is also available with accessories such as the packed or open lifting lever, test gag, balancing-
isolation bellows and heating jacket.
1. INSTALLING
Before installing the valve on the plant make sure that:
the line fluid is indicated on the construction declaration or is compatible with the construction materials;
the inlet piping in the valve are clean, impurities less, slag less etc. and eventually remove them.
the inlet and discharge piping are dimensioned in such a way that they generate the minimum possible loss of
pressure.
The mounting of the valve on the plant has to be carried out tightening the lock nuts in a crossed and uniform way.
Once the valve has been installed on the plant make sure that:
the discharge is not positioned in such a way to result dangerous for people or for instruments;
the discharge is properly conveyed .
1.1 SETTING UP
Before shipment all the safety valves are hydrostatically tested and set at the setting pressure required by the Client.
Therefore regulation in loco should not be necessary.
The maximum setting error is less than 3% for pressure up to 21 bar, with a minimum of 0,2 bar; it is less than 0,7
bar up to 70 bar; it is less than 1% for pressure over 70 bar.
In case it should be necessary to modify the set pressure or the re-closure pressure of the valve (blowdown) , it
should be necessary proceed as follows:
1.1.1 setting regulation ( referring to drawing )
In order to carry out setting regulation of the valve it is necessary:
remove the cap (11) and unloosen the lock nut (16);
turn the adjusting screw (10) clockwise in case the set pressure should be increased;
turn the adjusting screw (10) counter clockwise in case the pressure should be decreased.
The adjustment range of the spring setting is ± 5% of the set pressure indicated on the label of the valve.
Once the valve setting is regulated tighten the lock out (16) and re-screw the bonnet cap (11).
1.1.2 blowdown ring regulation (table 1)
In order to carry out the regulation of the blowdown ring execute the following operations:
loosen the screw (8);
raise the blowdown ring (5) by turning it counter-clockwise until touch the disc holder (3);
withdraw the blowdown ring (5) by turning it clockwise, as indicated in table 1;
tighten the screw (8) making sure it does not block the blowdown ring (5) but only that it prevents the blowdown
ring rotation.
If is required a more precise blowdown regulation, should be necessary carry out it with the valve installed on the
plant at full flow, taking into consideration that:
reducing the number of withdrawing notches it is favoured the opening and it is delayed the re-closure;
increasing the number of withdrawing notches it is delayed the full opening and it is favoured the re-closure.
2. DISASSEMBLING
In order to execute disassembling carry out progressively the following operations:
CAUTION : before disassembling the valve make sure that the plant on which it
is mounted is not “under pressure” and that no pressure inside
the valve itself has remained.
before disassembling the bonnet of the valve body make sure that the spring (13)
is totally released using the adjusting screw (10).
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