Product - DA-O Steam Desuperheater

​​​​​​Steam Desuperheater with Variable Section Spray Nozzle

The steam desuperheater DA-O provides reliable steam temperature control. The connection to the steam pipe as well as the spray water pipe are both flanged to facilitate service access. The DA-O is used for desuperheating of steam in small and medium sized pipes and is especially useful when the cooling water temperature is close to saturation.

Key features

The DA-O injection nozzle is screwed onto the body and secured by a lock washer

  • The nozzle itself has a spring loaded plug which extends as the pressure in the nozzle holder increases. The amount of water being injected by each nozzle is determined by a number of factors, including the diameter of the nozzle body opening, adjustment of the spring, and the pressure differential between thesteam inside the desuperheater and the water pipeline
  • The cooling water enters the inner nozzle chamber through a number of water channels. Water is rotated around the nozzle plug thanks to the special arrangement of the water channels. The plug and the seat are designed to create maximum water velocity at the nozzle edge point. The high velocity of the water when it leaves the nozzle guarantees fine atomisation, quickly evaporating the spray water
  • In order to maintain a constant pressure inside the injection nozzle, the latter is preloaded by a spring calibrated in function of the water/steam differential pressure


  • Maintains a constant water atomisation at any flow condition
  • Flanged connections facilitate service access during maintenance
  • Reliable steam temperature control
  • ”Flash-proof” – The design prevents water from atomising inside the nozzle regardless of cooling water temperature​

​Installation of DA-O

Select the installation point carefully. This is especially important in cases where the steam velocity is low and the steam temperature is close to saturation. It is equally important to install the temperature sensor where it, in a representative manner, can sense the temperature that shall be controlled. See II500.10 for desuperheater installation.​

Product specification

3 different nozzle sizes with two alternative csprings are available

Nozzle size

Turndown (Water)
Limited only by turndown of selected water control valve

Turndown (Steam)
Depends on steam velocity at full flow

Pressure class
DIN PN 16 - 320
ANSI / BS 150 - 2500

Required differential pressure
Min 2.5 bar / 36 psi
Max 30 bar / 435 psi
Angle connection
Straight connection

Nozzle body X40C​r13 (Werkstoff No.
1.4034, AISI 420)
Plug X20CrMoV12 1
(Werkstoff No. 1.4922)
Spring Heat resistant steel
Adjustment nut X20Cr13 (Werkstoff No.
1.4021, AISI 420)
Water flange 13CrMo44 or
Carbon Steel
Water pipe and 13CrMo44
steam flange

Nozzle size

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Product - DA-O Steam Desuperheater