High-Accuracy Orifice Plates
Precision differential pressure flow measurement solutions engineered to ISO 5167-2:2022 international standards. Daehan Instrument combines 35 years of expertise with cutting-edge technology to deliver industry-leading accuracy of ±0.25% to ±0.3%.
Our Orifice Plate Product Lines
DHOF-H Series (High Accuracy)
Precision Flow Measurement for Critical Applications
- Accuracy: ±0.25% to ±0.3%
- Material: 316L SS, Hastelloy C, Monel
- Pressure: Up to 420 bar (6000 PSI)
- Temperature: -200°C to 600°C
- Size Range: DN50 to DN1000
β ratio: 0.20 ≤ β ≤ 0.70
Reynolds: 5,000 ≤ ReD ≤ 10⁸
DHOF-S Series (Standard)
Reliable Performance for General Applications
- Accuracy: ±0.5% to ±1.0%
- Material: 304 SS, 316 SS
- Pressure: Up to 100 bar (1450 PSI)
- Temperature: -50°C to 400°C
- Size Range: DN25 to DN600
Water, Steam, Air, Natural Gas
Chemical Processing, HVAC Systems
DHOF-RTJ Series (Ring Type Joint)
High-Pressure Service with RTJ Flanges
- Accuracy: ±0.3% to ±0.5%
- RTJ Flange Compatible
- Pressure: Up to 690 bar (10000 PSI)
- Temperature: -50°C to 550°C
- API 6A Compliant
Oil & Gas, Petrochemical
Offshore Platforms, Refineries
ISO 5167-2 Technical Excellence
Our orifice plates are manufactured in strict accordance with ISO 5167-2:2022 standards, ensuring reliable and accurate flow measurement across all applications.
Optimized Beta Ratio
Precisely calculated β ratios between 0.10 and 0.75 for optimal differential pressure
Wide Reynolds Range
Validated for Reynolds numbers from 5,000 to 10⁸, covering all flow conditions
Superior Edge Quality
Edge radius ≤ 0.0004d with 90° ± 0.3° angle for consistent discharge coefficient
Precise Manufacturing
CNC machined to tolerances of ±0.001" ensuring repeatable performance
| Technical Parameter | ISO 5167-2 Requirement | Daehan Standard |
|---|---|---|
| Pipe Diameter Range | 50mm ≤ D ≤ 1000mm | 25mm ≤ D ≤ 1200mm |
| Beta Ratio (β) | 0.10 ≤ β ≤ 0.75 | 0.20 ≤ β ≤ 0.70 (optimized) |
| Plate Thickness (E) | 0.005D ≤ E ≤ 0.02D | Per ISO 5167-2 Section 5.1.6.2 |
| Upstream Edge Radius | r ≤ 0.0004d | r ≤ 0.0002d (enhanced) |
| Surface Roughness | Ra ≤ 10⁻⁴d | Ra ≤ 0.8 μm |
| Flatness Tolerance | 0.005D max | 0.003D (tighter control) |
Installation Requirements per ISO 5167
Straight Pipe Requirements:
Proper installation is critical for accurate measurement. ISO 5167-2 specifies minimum straight pipe lengths:
- Upstream: 10D to 44D depending on fitting type
- Downstream: Minimum 4D for all configurations
| Upstream Fitting | Minimum Straight Length | With Flow Conditioner |
|---|---|---|
| Single 90° Elbow | 10D | 7D |
| Two 90° Elbows (same plane) | 14D | 9D |
| Two 90° Elbows (different planes) | 34D | 19D |
| Reducer (2:1) | 25D | 14D |
| Full Bore Ball Valve | 12D | 8D |
| Control Valve (50% open) | 44D | 24D |
Why Choose Daehan Orifice Plates?
35 Years of Excellence
Established in 1989, trusted by industries worldwide
ISO Certified Manufacturing
ISO 9001:2015 & ISO 14001:2015 certified facility
In-House Calibration
KOLAS accredited flow calibration laboratory
Custom Engineering
Tailored solutions for unique applications
Sizing Software
Free calculation software per ISO 5167
Global Support
Technical support in multiple languages
Industry Applications
Oil & Gas
- Custody Transfer Metering
- Gas Distribution Networks
- Refinery Process Control
- Offshore Platform Monitoring
Power Generation
- Steam Flow Measurement
- Feedwater Control
- Cooling Water Systems
- Turbine Efficiency Monitoring
Chemical & Petrochemical
- Process Flow Control
- Reactor Feed Measurement
- Batch Process Monitoring
- Safety System Integration
Technical Resources
Download our comprehensive technical documentation and sizing tools
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