ASME PTC 19.5 Throat Tap Flow Nozzle
± 0.70% Uncalibrated Uncertainty
High Accuracy
- Line Size: 4” to 28”
- Head Loss % of Differential: 60% to 85% beta dependent (18-25% with optional outlet diffuser cone)
- Recommended Application, THROAT Reynolds Number: Greater than 500,000
ASME PTC 19.5 Throat Tap Flow Nozzle for High Accuracy Steam, Water, and Gas Measurement
The ASME PTC 19.5 throat tap flow nozzle from PFS is engineered for high-accuracy differential pressure flow measurement in demanding, high-velocity services. It is widely used for steam turbine efficiency testing in accordance with ASME PTC 6, while also supporting broader power and process applications that require precise, repeatable measurement without the full burden of formal performance test requirements.
A key advantage of the throat tap nozzle is flexibility. A standard ASME throat tap nozzle can be applied outside of turbine test scenarios while still delivering high-accuracy flow measurement. It can be manufactured and processed to match PTC 6 expectations when needed, yet calibration, upstream and downstream spools, and other test-related components are optional depending on the application. This allows teams to balance accuracy targets, installation constraints, and project budgets while maintaining a code-aligned nozzle design.
Key Benefits & Features:
- High Accuracy, With Calibration Options: Delivers strong baseline accuracy, with calibration available when you need tighter, more defensible results.
- Built for Steam and Water in Tough Conditions: Proven in high-pressure, high-temperature service for power and process applications.
- Consistent, Repeatable Measurement: Provides stable readings for testing, monitoring, and ongoing operations.
- Durable, Low Maintenance Design: No moving parts and a wear-resistant profile support long service life.
- Handles High Flow and High Velocity: Well-suited for high-rate applications where other devices may wear faster or lose stability.
- Designed to ASME Standards: Built to ASME PTC 19.5 and commonly used in power plant performance and efficiency testing.
- Head Loss Control Options: Standard designs have higher head loss, with diffuser options available to reduce pressure loss when needed.
Construction Standards
ASME Section I
ASME B31.1 Power Piping
ASME B31.3 Process Piping
Design Standards
ASME PTC-6
ASME PTC 19.5 Throat Tap Flow Nozzle Specifications
Uncalibrated: ± 0.70
ASME PTC 19.5 Throat Tap Flow Nozzle Models
Model Types
- PTFFR – PTC, Flanged Nozzle, Flanged Ends, Run
- PTFWR – PTC, Flanged Nozzle, Welded Ends, Run
- PTWFR – PTC, Welded Nozzle, Flanged Ends, Run
- PTWWR – PTC, Welded Nozzle, Welded Ends, Run
ASME PTC 19.5 Throat Tap Flow Nozzle Materials
Typical material selections for standard applications:
- Carbon Steel
- 304/316 Stainless Steel
- Chrome Moly
Other options for material selection (not limited to):
- Aluminum
- Zirconium
- Hastelloy B&C
- Monel
- Duplex SS
- Titanium
- Tantalum
- 321 SS
ASME PTC 19.5 Throat Tap Flow Nozzle Certifications
PFS is a contributor to various international standards committees, fully supporting our staff’s memberships to these commissions.
Individual products follow relevant industry regulations, including requirements specific to the oil and gas, water/wastewater, and power generation industries.
PFS maintains the following certifications, standards & compliances:
- ISO 9001
- AGA
- ASME S & U
- API
- ANSI
- European Pressure Equipment Directive (PED)
Applications
High-Velocity Industrial Applications
Across industrial operations, throat tap nozzles are used in high Reynolds number flow where durability and predictable performance are critical. Their robust construction supports long-term use in demanding clean fluid service.
Clean Steam, Gas, & Water Service
ASME throat tap flow nozzles provide dependable differential pressure measurement for clean steam, gas, and water applications, including high velocity service. Their standards-based design supports stable, repeatable results in test loops, utility systems, and controlled process environments.
Power Generation & Performance Testing
ASME throat tap flow nozzles are widely used in power plants for steam and feedwater measurement during performance and efficiency testing. Designed to meet ASME PTC 19.5 requirements, they support accurate, repeatable measurement in high-pressure, high-temperature service.
ASME PTC 19.5 Flow Nozzle Expertise and Support From PFS Since 1983
Four Decades of Flow Measurement Experience
PFS has over 40 years of experience designing and supporting differential pressure flow elements for demanding steam, gas, and clean liquid service. Our ASME PTC 19.5 throat tap flow nozzles are built for repeatable performance in applications where accurate, defensible results matter.
Engineering Support for Standards-Based Applications
From sizing and beta selection to tapping details and installation guidance, PFS helps ensure your nozzle aligns with ASME PTC 19.5 requirements and performs as intended. We support projects tied to testing, efficiency verification, and operational measurement where consistency and traceability are essential.
In-House Fabrication and Calibration Support
PFS provides end-to-end manufacturing and quality control, with optional laboratory calibration when tighter uncertainty is required. We deliver jobsite-ready assemblies with documentation and technical support to reduce installation risk and measurement uncertainty.
