Desuperheater -- Venturi Type Multi-Nozzle WCB
Steam Temperature Reduction Desuperheater by Direct Water Injection
Document No.SV-DS-DES-001
RevisionRev A
DateMay 2026
ManufacturerSupreme Valves India, Ahmedabad, Gujarat, India
This datasheet covers venturi-type multi-nozzle desuperheaters in WCB with SS316 internals for reducing superheated steam temperature by direct injection of atomised water in power, process, and steam distribution systems.
Technical Specifications
| Parameter | Specification |
|---|
| Size Range | DN50 to DN400 (2" to 16") |
| Pressure Rating | Class 300 / Class 600 |
| Body Material | WCB carbon steel with SS316 venturi liner and nozzle assembly |
| Nozzle Material | SS316 spring-loaded variable-area multi-nozzle array |
| Temperature Range | Steam inlet up to +540°C; outlet saturated to +250°C |
| Water Injection Pressure | Minimum 1.5 bar above steam pressure at injection point |
| Turndown Ratio | Up to 20:1 steam flow turndown with stable atomisation |
| End Connections | Flanged ASME B16.5, butt weld |
| Water Quality | Demineralised or condensate recommended; hardness < 0.1 ppm |
| Control | Separate temperature control loop with water injection modulating valve |
| Features | Multi-nozzle atomisation, spring-loaded variable area, venturi acceleration, low wetting length |
Materials of Construction
| Component | Material |
|---|
| Body | WCB carbon steel, sand cast, normalised, machined flange faces and nozzle mounting boss |
| Venturi Liner | SS316 investment cast venturi insert with polished internal surface for accelerated steam velocity |
| Nozzle Assembly | SS316 multi-nozzle manifold with spring-loaded variable-area pintle nozzles |
| Nozzle Springs | Inconel X-750 springs for high-temperature creep resistance and consistent nozzle opening pressure |
| Water Inlet | WCB or SS316 water inlet manifold with strainer and isolation valves |
| Gaskets | Spiral-wound SS316 + graphite for body/liner and flange joints |
| Internals | SS316 wear sleeves and guide bushings for nozzle alignment and erosion resistance |
Testing & Inspection
| Test | Requirement |
|---|
| Test Standard | Hydrostatic shell test 1.5x design pressure; spray pattern witness test |
| Certification | CE, PED, ISO 9001, IBR |
Applicable Standards
| Standard | Description |
|---|
| Design Standard | ASME B16.34 / HEI 2624 / VDI 2173 |
Notes
- Water injection pressure must exceed steam pressure by minimum 1.5 bar at the injection point; higher differential improves atomisation quality.
- Feedwater quality must be demineralised or condensate with hardness < 0.1 ppm to prevent nozzle erosion and scaling; install 100-mesh strainer upstream.
- Desuperheater must be installed in vertical downward or horizontal steam flow with minimum 5 straight pipe diameters upstream and 10 downstream.
- Temperature control loop must include fast-acting water control valve (1-2 second stroke) and PID controller with steam flow feed-forward.
- IBR inspection and Form III-C certificate required for boiler steam desuperheating applications in India; allow 3 weeks additional schedule.
