Principle:The PITOBAR Averaging Pitot Tube is used for flow measurement of saturated and superheated steam 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.
![DK_251-Main[1]](https://www.emcocontrols.com/wp-content/uploads/2022/05/DK_251-Main1.png)
![DK_251_3-Main[1]](https://www.emcocontrols.com/wp-content/uploads/2022/05/DK_251_3-Main1.png)
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
The condensing chamber is an integrated part of the probe
Certain installation requirements for straight pipe lines must be fulfilled in order to achieve the most accurate flow measurement. See table below.
Up-stream(x D) |
Down-stream(x D) |
|
|---|---|---|
|
Single 90° bend
|
9
|
3
|
|
Two or more 90° bends in the same plane
|
14
|
3
|
|
Two or more 90° bends in in different planes
|
24
|
4
|
Length |
DK200 @ 20°C |
DK200 @ 400°C |
DK250 @ 20°C |
DK250 @ 400°C |
|---|---|---|---|---|
|
200
|
3,75
|
1,81
|
|
|
|
300
|
1,66
|
0,81
|
2,52
|
1,19
|
|
400
|
0,94
|
0,45
|
1,42
|
0,67
|
|
500
|
0,60
|
0,29
|
0,91
|
0,43
|
|
600
|
0,42
|
0,20
|
0,63
|
0,30
|
|
700
|
0,31
|
0,15
|
0,46
|
0,22
|
|
800
|
0,23
|
0,11
|
0,35
|
0,17
|
|
1000
|
0,15
|
0,07
|
0,23
|
0,11
|
|
Design and calculation standards
|
VDI 2640, ASME, DIN, EN 13480
|
|
Types
|
DK251, DK251/3 with mounting flange, DK251/4 with 3 valve manifold, DK251/5 with 5 valve manifold
|
|
Pipe sizes
|
DN 100 - DN 2000, 4" - 80"
|
|
Pressure rating
|
PN 16 - 40, 150 - 300 lbs, ISO PN 20, 50 (for higher pressure ratings a welded construction will be offered instead of flanged)
|
|
Temperature range
|
-100°C - +450 °C
|
|
Material PITOBAR
|
Stainless steel AISI 316, other stainless grades on request
|
|
Material, mounting kit
|
carbon steel, stainless steel AISI 316, other on request
|
|
Process connection
|
Flange according to pressure rating
|
|
Flange standards
|
DIN, ANSI
|
|
Bottom support
|
for larger pipe sizes and high velocities
|
|
Instrument connection
|
DK251: ½" BSP, NPT or BW
|
|
Mounting
|
Welding to the pipe
|
|
Mounting neck
|
standard lengths, 130, 180, 250 mm, other lenghts available
|
|
Accuracy
|
± 1% accuracy of actual flow
|
|
Repeatability
|
± 0,1%
|
|
Reynolds no.
|
Minimum 100.000 at full flow
|
|
Rangeability
|
10:1
|
|
Max. fluid velocity
|
80 m/s
|
|
Probe size
|
25 x 25 mm
|
Accessories |
|
|---|---|
|
shut-off valves: needle or ball
|