Airflow Sciences Equipment, LLC

Dirty Air Pitot Probe

The dirty air pitot probe is utilized to measure air velocity, pressure, and temperature within a flow stream that is heavily laden with particulate. Compared to other pressure-type velocity probes, the design of the dirty air probe reduces the potential for pluggage of the pressure lines, a situation that will cause erroneous data. The probe is connected to a pressure gauge or electronic pressure transducer to measure the differential. A wind tunnel calibration is necessary in order to determine the calibration coefficient to obtain the flow velocity. An integrated thermocouple is used to measure the flow temperature.

The dirty air probe is generally used to measure the air or gas flow rate in pneumatic conveying systems. These may include piping or duct systems that transport cement, pulverized coal, lime, food products, or other similar dusts. The dirty air probe determines the velocity of the transport flow and thus can provide the data necessary to balance flows and avoid dust dropout due to low velocities. In addition, the air velocity is necessary if isokinetic particulate sampling is desired (i.e., ISO 9931, ASME PTC 4.2, etc.).

The dirty air probe from Airflow Sciences Equipment, LLC (ASE) can be manufactured to fit a variety of testing needs. Typical features are listed below, though custom orders are available:

• Probe body diameter – 1”• Probe length – 12” to 96”• Thermocouple – K-type• Level indicator (to ensure proper alignment to the flow direction) • Material – Sensing head 304 stainless steel; probe body 304 seamless stainless steel tube• Calibration – At 10 velocities in the range of 25 ft/sec to 150 ft/sec.

Airflow Sciences Equipment LLC – Dirty Air Pitot January 2013 Page 1 of 2

Velocity testing in a coal piping system

Pressure-sensing head design for dirty air probe

Typical dirty air probe(shown at left are flow alignment level, pressure line fittings, and thermocouple plug)

Dirty Air Velocity Test System

ASE can provide a probe only or a complete testing system. The Dirty Air Velocity Test Kit includes the following items:

• Dirty air velocity probe with thermocouple and calibration• Handheld digital manometer (pressure measurement range -5 to +15 inches of water)• Handheld thermocouple meter• Probe support bushing (threaded pipe that screws into test port and seals probe to port)• Tube umbilical (10' length, contains pressure and thermocouple lines)• Users manual• Shipping case• 1 year limited warranty• Email or telephone technical support (US Eastern time zone business hours)

Airflow Sciences Equipment LLC – Dirty Air Pitot January 2013 Page 2 of 2

Probe support / dustless connector

Digital manometer and thermocouple meter

Pressure line and thermocoupletube umbilical

Complete Dirty Air Pitot Test System