Variable Spray Desuperheater (VSD)
In order to recover lose of performance in a MSD or simple spray Desuperheater under low load conditions, variable nozzle spray type Desuperheater are recommended where as the load is reduced the spray nozzle area is also reduced.
The variable nozzle spray Desuperheater represents major advance in the design of Desuperheaters. It is small enough through to mount through a ND 100mm flange in the steam main having a minimum of 6 meters of straight pipe work downstream of the nozzle.
The variable nozzle spray Desuperheater (VSD) provides more economical control of steam temperature by introducing cooling water into the steam flow and through a nozzle of advance design. In this design water pressure above steam pressure is used to produce a thin film of conical spray of water which soon as evaporates as it is injected into the steam flow. The design of the Desuperheater eliminates the need for a separate water control Valve.
The valve is accurately built into the Desuperheater. Because there is no external water control valve and there is always maximum water pressure at the nozzle.
The equal percentage characteristic plug controls the amount of atomized water being injected. As per signals of the temperature controller the valve plug varies the area of the nozzle and the water which is directed through a cage has 12 water inlet orifices, progressively uncovers as per the lift of the plug. Water flow is controlled at the point of injection into the steam.
The VSD Desuperheater utilizes constant water pressure to create a fine conical spray of which is injected into the moving of steam. The Desuperheater water spray evaporates quickly, eliminating the impingement on the piping walls.
The actuator moves the Desuperheater control plug, which regulates the quantity of water not the pressure injected into the steam. Due to its unique design the VSD Desuperheater offers considerable advantage to the users.
For us to design most efficient Desuperheater for you, we need following parameters:
- Operating pressure of Steam
- Maximum Inlet temperature of Steam**
- Required Outlet temperature of Steam
- Steam Flow Rate**
- Available Cooling water Pressure
- Available Cooling water Temperature
** You can give all possible values for these parameters
Typical Pressure Reducing and Desuperheating unit (PRDS)
