High Beta® Flow Conditioner

Central to Flow Measurement

Eastern InstrumentsVAP3®/PA Pitots have a unique velocity averaging, parallel plate, proprietary design which provides an accurate differential pressure output that allows for precise airflow measurementand control of the combustion phase of power generation. With no upstream ports, the VAP3®/PA Pitot is resistant to plugging caused by airborne particulate and is, therefore, perfect for measuring Primary, Secondary and Over-Fired airflow, especially when coupled with the High Beta® Flow Conditioner.

VAP3®/PA Pitot

Features and Benefits

  • Velocity Averaging Parallel Plate Design— Multiple DP Sensing ports allow velocity averaging across the full traverse of the duct
  • VAP3®/PA Pitot Configuration: Resists airborne particulate plugging
  • Teflon® Hard Anodized 6063 Aluminum Construction—Hardened for long life expectancy
  • Controlled Port Profiling—Ensures repeatable measurement for higher degree of accuracy
  • No Moving Parts—Virtually no spare parts or maintenance costs
  • Simple, Robust Design: Very few process penetrations with optional boltin installation




HighBeta® Eastern Instruments

Air Flow Measurement With Limited Straight Duct Runs

The High Beta® Flow Conditioner incorporates an array of VAP3®/PA Pitots with flow straightening vanes and a converging duct section to condition airflow at the point of measurement. Reducing the effects of turbulent, reverse and cyclonic air flow patterns in complex duct systems, the High Beta® maximizes the accuracy of the flow measurement and is a great replacement for a wide variety of air flow measurement devices including airfoils.


Primary & Tempering Air Applications

  • Accurate Airflow Measurement
  • Greater Air/Fuel Ratio Control
  • Improved Pulverizer Air Inlet/Outlet Temperature Control
  • Improved Primary Air/Fuel Ratio over Broader Ranges
  • More Stable Control of the Mixed Air Amount

Secondary Air Applications

  • Accurate Airflow Measurement
  • Reduced Pressure Drop
  • Virtually No Straight Duct Runs Are Required
  • Replaces Airfoils and Venturi


Secondary air compartmentalized windbox airfoil replacement


Secondary air common windbox airfoil replacement

Improving Airflow Control and Accuracy

The Temperature Stratification Problem
CFD temperature diagram

CFD showing temperature stratification across air measurement plane

  • Current practices include measuring Primary airflow downstream of the hot and tempering|air duct mixing point
  • Studies show that this measurement location has a high temperature stratification with differences in temperature as high as 400oF
  • Extreme temperature stratification affects the air’s density, making it vary drastically across the measurement plane
  • For mass flow measurement calculations, a given density must be used and is often assumed to be the same across the measurement plane
  • Primary airflow measurements can have errors as high as ±20% because of high temperature stratification and the use of a singular, assumed density value

High Beta® installation

High Beta® installation in duct sections upstream from the mixing point

Why Measure Primary Air?

  • Greater air/fuel ratio control which improves NOx where primary air is the critical value
  • Improved primary air/fuel ratio even during load changes and over broader ranges
  • More stable control of the mass flow as well as temperature, of primary airflow
  • Improved pulverizer inlet and exit temperatures which can reduce pulverizer fires
  • Greater control of entire combustion phase