Description
The PITOBAR Averaging Pitot Tube is used for flow measurement of liquid and gasses in horizontal or vertical pipe lines. The PITOBAR Averaging Pitot Tube principle of operation is derived from the classic or single point pitot tube. As opposed to the single point pitot tube, the PITOBAR averaging pitot tube has a number of holes depending of pipe size pointing towards the up-stream side. One port pointing down stream measures the static pressure. The PITOBAR has very low installation costs and the pressure loss is low compared to other flow elements, especially in larger pipe sizes.
The PITOBAR Averaging Pitot Tube is constructed and designed with a diamond shaped strut with several ports spaced centrally within concentric rings of equal area pointing towards the upstream side. This is done in order to get the best averaging measurement of the dynamic pressure, resulting in a more
accurate flow reading. The pitot tube creates a differential pressure signal which is proportional to the flow rate.
Differential Pressure = ( Pstatic + Pdynamic) – Pstatic.
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Design and calculation standards
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VDE/VDI 2640, ASME, DIN, EN 13480
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Types
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DK200 & DK250
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Pipe sizes
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DK200: 3" - 40" | DK250: 4" - 80"
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Probe sizes
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DK200: 20 x 20 mm | DK250: 25 x 25 mm
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Pressure rating
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PN 16 - 400, 150 - 2500 lbs
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Temperature range
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-100°C - +350 °C
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Material PITOBAR
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Stainless steel AISI 316, other stainless grades on request
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Material mounting part
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Carbon steel, stainless steel AISI 316, other on request
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Process connection
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Flange according to pressure rating
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Flange standards
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DIN, ANSI
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Bottom support
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For larger pipe sizes and high velocities
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Mounting
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Welding to the pipe
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Instrument connection
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½" BSP or NPT, Weld ends Ø21,3
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Mounting neck
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Standard lengths, 130, 180, 250 mm, other lenghts available
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Accuracy
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± 1% accuracy of actual flow
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Repeatability
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± 0,1%
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Reynolds no.
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Minimum 100.000 at full flow
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Rangeability
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10:1
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Max. fluid velocity
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liquids 5 m/s, gasses 80 m/s
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Shut-off valves: needle or ball
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Certain installation requirements for straight pipe lines must be fulfilled in order to achieve the most accurate flow measurement. See table below.
Upstream (x D) |
Downstream (x D) |
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Single 90° bend
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9
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3
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Two or more 90° bends in the same plane
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14
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3
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Two or more 90° bends in in different planes
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24
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4
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Without bottom support, with reference to mechanical bend. Pressure is measured in bar. See table below.
Length |
DK200 @ 20°C |
DK200 @ 400°C |
DK250 @ 20°C |
DK250 @ 400°C |
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200
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3,75
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1,81
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300
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1,66
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0,81
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2,52
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1,19
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400
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0,94
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0,45
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1,42
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0,67
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500
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0,60
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0,29
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0,91
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0,43
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600
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0,42
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0,20
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0,63
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0,30
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700
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0,31
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0,15
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0,46
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0,22
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800
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0,23
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0,11
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0,35
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0,17
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1000
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0,15
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0,07
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0,23
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0,11
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