FLOW NOZZLES

Flow nozzles are widely used for differential pressure (DP) flow measurement, particularly in large pipelines. They offer high accuracy in high-velocity applications and are well-suited for hydrocarbon gases, liquids, and steam due to their robust construction and low maintenance needs. Their contoured design reduces wear compared to orifice plates, though they still require straight pipe runs for optimal performance.

Key Benefits:

Lower pressure drop than orifice plates, improving efficiency.
Suitable for extreme conditions (high temperature, pressure, and velocity).
Durable against wear and erosion, reducing maintenance needs.
Better suited for steam and high-speed flow applications.

Challenges:

Higher initial cost due to bespoke fabrication.
Installation complexity requiring precise alignment (less critical when supplied as part of a pipe run).
Permanent pressure loss, though lower than orifice plates.
Straight pipe run requirements, which may limit compact layouts.

Impact on Pipe Runs:

Positive: Reliable and repeatable measurement, process efficiency improvements, and compatibility with existing systems.
Negative: Space constraints, possible structural reinforcement needs, and potential fouling in hydrocarbon liquids.

Conclusion:

Flow nozzles are a preferred choice for large-diameter pipelines handling hydrocarbon gases, liquids, and steam. Their durability and accuracy outweigh their higher cost and installation complexity, making them a reliable flow measurement solution in demanding industrial environments.

Slip type and Weld-in Block

General purpose for use on all fluids, combines features of orifice plate and flow nozzle.
Lower pressure loss than orifice plate and lower cost than flow nozzle.
Easy installation, fits between flanges.
Accuracy +/- 5%, with flow rig cal +/- 2% percent
Does not conform to BS1042 or ISO5167

High velocity flow measurement of non-viscous fluids
Suitable for abrasive fluids or fluids with suspended solids
Commonly used on steam boiler plant and in steam distribution
Accurate and reliable with low pressure loss and long installed life
Materials 316SS, monel, bronze, aluminium or hastelloy-C
Slip type (between existing flanges), or weld-in nozzle block
ISA-1932 nozzle or long radius body types
Line sizes from 50 to 300 mm

We recommend the flow nozzle for accurate reliable flow measurement. It has a long working life in difficult process environments and can easily be installed and maintained by non-technical staff in remote locations.

Flow metering accuracy, unlike many modern electronic flow instruments, can be checked by physical inspection of internal bore and careful measurement with vernier calipers.