Baker Hughes Masoneilan 41005 Series, Instruction Manual

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Masoneilan 41005 Series Globe Valves with API-6A Capabilities Instruction Manual
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4. Disassembly
4.1 Removal of Actuator
(Figures 9, 10, 11, 12, and 13)
Access to the internal components of the body should be
accomplished with the actuator removed. To carry out this
operation, follow the instructions below and refer
to the specific actuator instructions, reference 19530 for a
type 87/88 actuator and 31188 for types 51/52/53.
4.1.1 Disconnection of instruments
Disconnect all mechanical couplings between the positioner
and the other instruments on the one hand and the valve
stem/actuator stem coupling on the
other hand.
4.1.2 Plug stems screwed into the actuator stem
In the case of air-to-retract actuators, apply sufficient air
pressure on the diaphragm to retract the stem completely.
Loosen the counter-nut, unscrew the stem.
During this operation, make sure that the plug does
not turn when it is seated. If the plug travel is very
small and there is a large amount of plug stem inside
the actuator, it may be necessary to remove the
yoke nut and lift the actuator so that the plug is not
touching the seat.
4.1.3 Stems attached with a stem connector
In the case of air-to-retract actuators, apply sufficient air
pressure on the diaphragm to retract the stem completely.
Loosen the screws and remove the stem connector.
4.1.4 Removal of actuator
Disconnect all the ingoing and outgoing air and electrical
connections from the actuator. Loosen the yoke nut or
attachment screws and lift the actuator, making sure
that the concentricity and/or the thread of the bonnet is not
damaged.
4.2 Opening of the Pressurized
Chamber
(Figures 15, 16, 17, 18, and 19)
Prior to disassembly, vent the process pressure
and isolate the valve if necessary.
Note:
The valve must always be reassembled with
new packing rings and gaskets; before disassembly,
make sure that the appropriate parts are available.
A. Remove the packing flange nuts (3) then remove the
packing flange (4) and the packing follower (23).
B. Check that the exposed part of the valve plug
stem (1) is clean enough for the bonnet (7) to be
removed easily.
C. Remove the body stud nuts (8).
D. By means of a pad eye secured instead of the
actuator, lift the bonnet (7) up and separate it from the
valve body (18). During this operation, the valve plug
stem (1) must be pushed downwards so that
the valve plug remains in the valve body (18).
E. Remove the spring washer (17) and the body gasket
(10).
F. In the case of type 41305, 41375, 41505, 41605 and
41905 valves, remove the valve plug stem (1) and
valve plug (15) assembly from the cage by pulling the
valve plug stem upward, then remove the cage (16)
and ‘stack’ (37) assembly for 41375 type valve.
In case of a 41905 series valve [equipped with a
graphite ring (45)], make sure that the ring is not
damaged during the operation.
G. In case of a 41405 valve, remove the valve plug and
body cage assembly by pulling the valve stem upward:
in this case, the valve plug has a shoulder which
prevents the cage from falling. Remove the valve plug
from the cage by pulling on the end of the plug stem.
H. Remove the seat ring (13) and the seat ring gasket
(14) form the valve body (18).
I. Remove the the packing (6), the packing spacer (5)
and the guide bushing (22) from the bonnet (7). (on
the next line add a note) Note: A packing spacer (5) is
only mounted when the bonnet has a side connection.
Because of the plug balance seal (31), the
cage can sometimes be lifted along with the
valve plug. If this should happen, press down
on the cage so that it remains in the body. If
the cage is lifted along with the valve plug, it
could slip during handling and fall.