The trend to improve efficiency in today’s power plant environment drives the need for effective boiler trim controls which, in turn, requires accurate air flow measurement. Air flow measurement that is not repeatable, accurate, or representative of mass flow can destabilize the airflow control loop. Air flow is at its most accurate when the flow being measured has no turbulent, reverse, or cyclonic flow patterns and is evenly profiled across the duct at the measurement point.

The High Beta® Engineered (HBE) flow conditioner is ideal for profiling even the most turbulent flows and is perfect for applications where ducts are not uniform or are irregular in size and shape, such as those seen in the duct work of power plants measuring Primary Air, Secondary Air or Overfired Air.

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The combustion process can be understood as a "mass-based" relationship in which optimization occurs through the stochiometric balance between the mass of air and the mass of fuel or feed stock being combusted. Whether the fuel is coal or a biomass feed stock such as wood chips, construction debris, or even soybeans or sugar cane, the proper fuel-to-air ratio is critical to increasing the efficiency of the burners and maintaining an optimum temperature for the boilers.

The High Beta^® Engineered flow conditioner is a proprietary-designed flow-conditioning device that is designed to minimize pressure loss while straightening flow in ducts with relatively few or almost no straight duct runs upstream and/or downstream. Eliminating cyclonic, turbulent, and reverse flow at the point of measurement, the High Beta^® optimizes flow conditions so that the accompanying VAP^3® Pitots can obtain their maximum accuracy.

The High Beta^® consists of a flanged 304 stainless steel duct section that can be inserted into either round or rectangular ducts. A converging section effectively straightens the flow profile and accelerates air through its round measurement area. An array of VAP^3® pitots is housed within each HBE that will provide an accurate differential pressure output for the highest degree of air flow measurement and control of your process. The High Beta^® is erosion resistant and can handle typical process temperatures up to 700°F.

Additionally, the High Beta^® can be *NIST reference calibrated prior to installation. Typical *NIST calibrated total flow uncertainties can be as low as ±0.50% over the calibrated range.

In many cases, pitot tubes have one port facing into the air stream (high), and one port at 90° to the air stream (low). The differential pressure between the “high” and “low” ports represents the velocity. Situated in this way, however, the "high" port is vulnerable to plugging from airborne particulate including fly ash.

The HBE is equipped with VAP^3® pitots which place the “high” port inline with airflow, which means it has no impact ports and is thus, resistant to the plugging issues associated with standard pitots.

Differential Pressure System - DPS

The DPS, when coupled to the VAP^3® pitot, is used to deliver flow measurement for process and power applications. The microprocessor-based flow transmitter consists of a differential pressure transmitter and flow processor. The system transmits an analog output signal that is proportional to flow. The processor enables the DPS to take a temperature and/or a duct static pressure input signal, providing a density-compensated output signal in wide range of flow units. With the fast scan time of the DPS and a selectable moving average of the display and output variables, the DPS can deliver a reliable, accurate signal, converting the fast response of the VAP^3® pitot to the digital control systems of today. The DPS can be used in conjunction with the Line Mounted Purge (listed below).

Differential Pressure Unit - DPU

The DPU, when coupled to the VAP^3® pitot is used to deliver accurate, dependable flow measurement in process and power applications. The Pressure and Flow Transmitter and Display Unit consists of a differential pressure transmitter and an optional display. The DPU can be configured to display differential pressure or flow rate and will transmit a 4-20mA analog output signal that is proportional to the displayed value. The DPU can also be configured to simply be an enclosed pressure unit with or without a display and transmit the actual differential pressure in a 4-20mA signal. The DPU can be used in conjunction with the Line Mounted Purge Block (listed below).

Differential Pressure Gauge - DPG

The DPG, when coupled to the VAP^3® pitot, is used to deliver a reliable flow measurement for process and power applications. The Pressure and Flow Display consists of a differential pressure gauge manifolded within an industrial enclosure. It can be configured to display differential pressure in inches of H₂O, as well as flow rate in customer defined units. The unit is accurate to within +/- 2% and is suited for clean, dry, non-corrosive air. It is rated for internal pressures from -10 to 10 psig (-68.6 to 68.9 kPa) and temperatures from 20° to 140° F (-6.67° to 60° C). When just a differential pressure display is needed, the DPG is the ideal solution.

Remote Temperature Sensor - RTS

The Remote Temperature Sensor (RTS) is a temperature-measuring device that can be remotely mounted to a duct or pipe via a half coupling. It is the perfect alternative when an integrated temperature option cannot be used with a VAP^3® Pitot or when a High Beta^® Flow-conditioning device is installed. When used with a DPS flow transmitter, the RTS can provide the temperature input when temperature and pressure correction are required.

Line Mounted Purge - LMP

The Line Mounted Purge (LMP) is a continuous purge system intended to be used with VAP^3® Pitots by Eastern Instruments. The LMP is designed to supply a continuous balanced flow of air through the impulse lines and out of the probes sensing ports during flow measurement. The unit consists of an anodized aluminum purge block and capillary/internal filter set with ports tapped to receive NPT fittings, an optional mounting bracket (ordered separately), and a filter assembly.