Flow Nozzle (DH-FN Series) | High-Temperature, High-Pressure Steam Flow Meter

Product Overview

Precision Flow Meter for Extreme Conditions

The flow nozzle is a DP flow meter that combines the advantages of the orifice plate and the venturi. It excels at high-temperature, high-pressure steam measurement and delivers stable performance in extreme conditions such as power plant turbine inlets.

✓ Pressure loss: 30–50% (40% less than an orifice plate)
✓ Measurement accuracy: ±0.5% to ±1.0%
✓ Max. temperature: 600°C (special materials)
✓ Max. pressure: 400 bar
✓ Beta ratio range: 0.3 to 0.8

💡 Why choose it:

More economical than a costly venturi, yet its lower pressure loss than an orifice plate reduces long-term operating costs.

ISA 1932 standard nozzle cross-section

Key Features

🎯

High accuracy

±0.5% accuracy through ASME PTC 6 compliance

💪

Robust Construction

Streamlined design minimizes wear; service life over 20 years

🔥

Extreme Conditions

Stable measurement at 600°C and 400 bar

💰

Cost-Effective

50% of venturi cost, 40% less pressure loss

⚡

Fast Response

Responds instantly to rapid flow changes

🛡️

Self-Protecting

Design prevents debris build-up

Technical Specifications

Standard Specifications

Item	Specification	Remarks
Applicable Standards	ASME PTC 6, ISO 5167-3, ISA 1932	International Standards Compliance
Pipe Size	50mm ~ 1,500mm	2" ~ 60"
Beta Ratio (β)	0.3 ~ 0.8	Optimal: 0.45 to 0.65
Measurement Accuracy	±0.5% ~ ±1.0%	±0.5% when calibrated
Pressure Loss	30% to 50% of DP	Varies with beta ratio
Reynolds Number	10⁴ ~ 10⁷	Minimum 10,000
Straight Run	10D upstream, 5D downstream	Without disturbances
Temperature range	-200°C ~ 600°C	Depends on material
Pressure rating	Class 150 ~ 2500	Up to 400 bar

Material Selection

Materials	Temperature	Fluids	Features
SS 316/316L	-200°C ~ 450°C	General process	Standard material
SS 321	-200°C ~ 550°C	High-temperature steam	Excellent heat resistance
Chrome-Moly	-30°C ~ 600°C	High-temp., high-pressure steam	Power plant standard
Hastelloy C	-200°C ~ 450°C	Corrosive Fluids	Corrosion resistance
Monel	-200°C ~ 400°C	Seawater, chlorine	Offshore plants

Applications

⚡ Power Plants

• Main steam / reheat steam lines
• Turbine inlet flow
• Boiler feedwater
• Bypass steam

Reference: Taean Thermal Power Plant Units 9 & 10

🏭 Petrochemical

• High-temperature process gas
• Reactor feed/discharge
• Cracking furnace steam
• Flare gas

Reference: Ulsan Petrochemical Complex

🔥 Steel Mills

• Blast furnace gas
• Coke oven gas
• Hot stove air
• Cooling water systems

Reference: POSCO Gwangyang Steelworks

Flow Meter Comparison

Criteria	Flow Nozzle	Orifice	Venturi
Pressure Loss	30~50%	60~70%	10~15%
Initial cost	Medium	Low	High
Installation space	Short	Very short	Long
Accuracy	±0.5~1%	±0.5~2%	±0.5%
High-temp. suitability	● Excellent	● Good	▲ Fair
Maintenance	● Minimal	▲ Periodic	● Minimal