3.531.5275.200
11
6. Maintenance
Note: Before actioning any maintenance operation observe the ‘General safety information’
in Section 1.
Maintenance operations must be carried out by qualified staff, properly equipped and provided with
original spare parts.
Before disassembling the valve from the plant, disconnect and adequately support the concerned
pipe parts.
6.1 When carry out maintenance
It is advisable to check the valve after some time, to solve simple problems that may become
dangerous in the future. Such period of time depends on features and effective use of the plant (type
of fluid, temperature, pressure, etc.) and must be fixed from the person in charge of plant maintenance.
6.2 Basic controls
To guarantee safe and enduring use of the fitted valves, the following inspections should be
performed:
-
Visual inspection of the body:
visually check searching for appeared roughness, possible
aroused damages, corrosion or erosion.
-
Lubrication of the stem:
it is recommended to apply to the stem thread a small quantity of
graphite-based or copper-based grease to avoid irregular friction or jamming.
-
Checking of the body-cover and of flange-bolts clamping:
after the use of the valve in a
continuous cycle of the plant, it is recommended to verify the tightening of components.
6.3 Operation for leakages
-
Leakage of connections:
it is necessary to depressurize the system and replace the gaskets,
referring to section 4, “Installation”.
-
Leakage between valve seat and plug:
this fault is generally caused by foreign bodies entrapped
between the inner valve surfaces; the use of the valve in such a situation over an extended period
of time could cause irreparable damages. The prompt intervention, grinding the seat and plug can
restore the functionality.
-
Stem packing leakage:
this is the most frequently worn out point of the valve; it is therefore
required to carry out periodic compression of graphite rings referring to work conditions.
-
Procedure for compression of stem packing ring:
depressurize the system.
For threaded valves GXMZ series, tighten the compression nut of the rings; for valves GXM16Z
series tighten alternatively the
fl
ange compression nuts, paying attention to maintain it perpendi-
cular to the stem axis. It should be noted that the compression of the gasket rings increases the
operating torque of the valve. Should this operation fail to restore tightness, it is required to replace
the rings.
-
Leak between body and cap:
depressurize the system.
•
For GXM valves
always operate with open plug; unscrew the threaded cap or loosen the
screws which
fi
x the cap to the valve body, acting alternatively and with crossing procedure.
Verify integrity and good conditions inside the valve body. Remove the old body gasket and
accurately clean the contact surfaces. Using a new gasket, refit the parts and, in case of bridge
cap, tighten the bolts alternatively and with a crossing procedure.
•
For RJ216Z check valves
, loosen the fixing screws between body and cap alternatively and
with a crossing procedure. Pay attention to the thrust of the plug internal spring. Verify integrity
and good conditions of the inside valve body. Remove the old body gasket and accurately clean
the contact surfaces. Using a new gasket, refit the parts and tighten the bolts alternatively and
with a crossing procedure.
•
For RJ205Z and RJ205N check valves
, unscrew the cap and verify clearness and good
conditions inside the valve body. Remove the old gasket and accurately clean the contact
surfaces. Using a new gasket, carry out the assemblage and clamp the cap.
Summary of Contents for GXM16Z
Page 2: ...3 531 5275 200 2...
