Control valves
Desuperheaters
Typical applications:
-
To reduce the temperature of steam discharged from turbine by-pass systems on power plants for heat exchangers, dump stations
etc.
-
To improve heat transfer of indirect contact heat exchangers - shell and tube , plate type, reactor heating jackets etc.
-
To reduce the temperature of steam on direct contact applications - food cooking kettles, in-line steam heaters, tobacco drying
plant and paper mills.
Features:
-
Low cost simple, robust design.
-
Minimal steam pressure drop.
-
Flexible design options.
Standards and approvals
Spirax Sarco desuperheaters are available built to ASME B 16.34
design code. Also available are ASME VIII Division 1.
This product fully complies with the requirements of the European
Pressure Equipment Directive 97 / 23 / EC and carries the CE
mark when so required.
Welding is in accordance with ASME IX.
Connections (EN 1092 or ASME B16.5) are sized to suit the
process conditions.
Standard ASTM materials of construction include: Carbon steel,
Stainless steel, Chrome molybdenum steel etc.,
Certification
The following certificates / documents can be supplied at an
additional cost:
-
Material certificates to EN 10204 3.1 with a corresponding
material location diagram.
-
NDT reports.
Air signal
12
11
10
15
The VAD lift should be controlled by use of a positioner, the
maximum air pressure on the actuator should be limited to
4 bar g.
The fail safe position of the standard VAD unit is in the shut
off position, spring-retact and will shut off water when retracted.
Optionally, if request at the point of order, the unit can be
supplied in the fail safe open position and the unit nomenclature
will be denoted by an 'E' (for spring-extend) in the description i.e.
VAD a E.
Positioners
8
9
7
6
5
4
3
2
1
Compatible with PP5, EP5, ISP5, SP400 and SP500 positioners.
Material
No. Part
1 Nozzle
2 Seat
3 Plug
4 Lock-nut
5 Stem
6 Bottom pipe extension
7 Main steam flange
8 Water flange
9 Top pipe extension
10 Packing
11 Packing bolting
12 Nut
13 Setting nut
14 Seat gasket
15 Stem bearing
Material
Stainless steel
Stainless steel
Stainless steel
Stainless steel
Stainless steel
Carbon steel
Carbon steel
Carbon steel
Carbon steel
Graphite
Stainless steel
Stainless steel
Stainless steel
Graphite
Stellite Grade 6
AISI 431
AISI 431
AISI 431
ASTM A105N
ASTM A105N
ASTM A105N
14
13
Alternative material: Depending of the condition of use, Spirax
Sarco can could change the carbon steel body material to alloy
steel or stainless steel.
Please note:
The parts identified in the illustration above are exactly the
same for both the VAD a and the VAD b
TI-P451-01 CH Issue 3
Page 3 of 7
VAD Variable Area Desuperheaters
4.8.26
