Instruction Manual
D103643X012
DFA Desuperheater
August 2013
8
Table 7. AF Nozzle Specifications
NOZZLE TYPE
PLUG TRAVEL, INCHES
AF7
0.014
AF10
0.028
AF14
0.029
AF17
0.034
AF20
0.036
AF24
0.042
AF28
0.048
AF32
0.056
AF35
0.065
AF40
0.063
AF44
0.069
Figure 5. Spray Nozzle Tack Weld Locations
GA26453-B
AF STYLE NOZZLE
WIRE, TACK
WELD ON BOTH ENDS
ORIENTATION OF FLATS NOT CRITICAL
To further check the spring, the spring can be removed by first removing the pin, using a small drill bit as a punch and
unscrewing the spring casing from the plug stem. The nozzle can be reassembled by following a reverse order of
disassembly, taking care to line the hole in the plug stem up with the hole in the spring casing, then pressing the pin
back into place through the two parts.
9. The travel can be determined by using a feeler gauge to measure the distance between the nozzle body near the
water injection ports to the side of the spring casing as outlined in figure 4. This measurement must match the
factory set plug travel for the corresponding nozzle type as shown in table 7.
10. Inspect nozzle threads for damage and clean if needed; if damage is present, nozzle replacement will be
necessary.
11. Rinse both the desuperheater body and nozzle to remove particulate.
12. Screw nozzle into the desuperheater body and tighten just until the spray head is flat and tight against the
desuperheater body.
13. Tack
weld a small piece of welding wire onto the nozzle mount next to either of the spray head flats to prevent
rotation during service (refer to figure 5). Maintain low heat to prevent distortion of the nozzle.
14. Reinstall the desuperheater into the line, using a reverse order of assembly; refer to the installation instructions to
complete this step. Make sure the mounting flange gasket (customer supplied) is replaced with a new one.
