2017 PRI Trade Show
Indianapolis, IN
Dec. 7 - 9 
Audie Tech Booth # 5132, 5134

 
Pitot Tubes PDF Print E-mail

Audie Technology Pitot Tubes

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Specially Designed for use with Flow benches
Pitot tubes are used to measure air velocity. They sample the impact pressure of the air into the tip of the probe, and the static pressure in the same region simultaneously. To work correctly the tip of the probe must face into the air flow.

Audie Technology pitot tubes are properly shaped for use with heads. Each set contains a straight probe (for exhaust ports) and a probe with a U bend at the tip (for intake ports). They feature durable stainless steel construction and a thinner profile (3/32 inch, 2.38 mm OD) than other commonly available tubes so they disturb the air flow less. Their length (18 inch, 457 mm) lets you keep your hands away from the port entrance.

How Pitot Tubes Work
PA pitot tube has an inner and outer tube.  The tubes are sealed together at the tip, with the inner tube left open.  A short distance from the tip there are several holes around the outer tube.  Pitot tubes measure the impact pressure produced by moving air.  This is called the "dynamic pressure".  The pressure in the port that is not caused by moving air is called the "static pressure".

The tube must be positioned so that the air flows directly into the tip.  The inner tube then has a pressure that is a combination of the dynamic pressure and the static pressure.  The outer tube has only the static pressure.  By connecting a differential pressure sensor between the inner and outer tube we can measure only the dynamic pressure.  If the density of the air is known, the air speed can be calculated from the dynamic pressure.

How to Use Pitot Tubes
  1. Use the pitot tube that will allow the air to flow directly into the tip of the pitot tube.  Use the "J" tube for intake ports, and the straight tube for exhaust ports.
  2. Connect the pitot tube to a differential pressure sensor or a manometer.  When using a single tube manometer, connect E to the bottom of the manometer and F to the top.  When using Flow Pro sensors connect E and F to the nipples labeled E and F.
  3. Put the pitot tube into the air flow.  Adjust its angle or position to get the maximum reading.  When the reading is at its maximum the air is flowing directly into the tip.
  4. Record the reading.  When using Flow Pro sensors, press the foot switch.  Repeatability will be better if you hold the foot switch down for several seconds.  Flow Pro software will average readings taken while the switch is pressed.
Ways to Use Pitot Tubes
  1. "Poke-around" Testing. The pitot tube is used to probe the port looking for fast air and dead air.
  2. Port Mapping. Readings are taken in a systematic manner in order to map the air speeds in the port. This is done at one or more cross-sectional planes. Flow Pro software helps greatly in gathering and analyzing port maps.


 
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