6
Aisi 304
Aisi 304
Figure 10
details
equally spaced
Tack (3)
Tack (1)
min. 8 mm
Body
extension
Tack (2)
Tack (4)
tack welding
After reassembly, the spray cylinder should
be tack welded for security. it is essential that
this welding is carried out by a competent
welder. A Welding procedure specification
is available from yarway, upon request. Both
Tig and ArC welding methods are acceptable
and the recommended electrode material
is er niCrmo3. A minimum of 4 (model 37)
or 8 (model 47) 8 mm long tacks are required,
diametrically opposite, with one weld securing
the fastener ring to the body extension, the
other securing the spray cylinder to the
fastener ring. After welding, use a suitable
dye penetrant method to check the weld. no
cracks are permitted. if necessary, grind-off,
re-check until a satisfactory weld is obtained
(see Figure 10).
YarwaY
A.T.-Temp CryogeniC desuperheATer sTAndArd duTy
InstallatIon and MaIntenance InstructIons
re-installation
refit the actuator onto the A.T.-Temp
Cryogenic desuperheater, referring to the
notes taken during disassembly, for re-setting
the stem position.
spare parts
make sure that the identification number
(indicated on the nameplate) is verified and
specified when ordering spare parts. For
cross-sectional drawings and part lists,
see the next page.
Before re-installing the A.T.-Temp Cryogenic
desuperheater, make sure that the connecting
flange faces are cleaned thoroughly and any
gasket material removed. insert the A.T.-Temp
Cryogenic desuperheater into the pipework
and check that the nozzle is orientated
correctly with the spray with the direction
of the gas flow. Apply a suitable lubricating
compound to the bolts and nuts and tighten
evenly, in accordance with the manufacturer’s
recommendations. Before connecting the
liquid line, flush through and check for any
contamination or restriction in the supply.
Follow the procedure for ‘start-up’, as detailed
earlier in the installation instructions. Check
the flange and stuffing box tightness. do not
overtighten the stuffing box packing gland as
this may prevent proper A.T.-Temp Cryogenic
desuperheater operation. in the event of
persistent leakage through the stem packing,
the unit should be removed to the workshop,
for further examination. experience shows that
providing the stuffing box, packing and stem
are clean and score, leak-free tightness can be
achieved. Tighten stuffing box by evenly turning
the nuts compressing the springs.
reassembly
Before reassembling the valve, lubricate all
threads with a suitable anti-seize compound
such as nickel based compounds. do not use
grease or other oil based lubricants as these
may lead to dismantling problems later.
reassemble the spray cylinder onto the body
extension. use a fine grade polishing paste
to lap the seating area of cylinder and body
extension. The seal is metal to metal so a
concentric seat area is vital. Always use a new
fastener ring. set the spray cylinder into the
correct orientation (the liquid spray should
always be in the same direction as the gas flow)
and tighten the fastener ring.
