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PITOBAR Averaging Pitot Tube for Direct Transmitter Mounting
Type DK203, DK204, DK205,
DK253, DK254, DK255

Principle: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.

Advantages:

Construction

 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

Construction
Design and calculation standards
VDE/VDI 2640, ASME, DIN, EN 13480
Types
DK203 & DK253 with mounting flange. DK204 & DK254 with 3 valve manifold. DK205 & DK255 with 5 valve manifold
Pipe sizes
DK20X: DN80 - DN 1000, 3" - 40" | DK25X: DN80 -DN 2000, 3" - 80"
Probe sizes
DK20X: 20 x 20 mm | DK25X: 25 x 25 mm
Pressure rating
PN 16 - 400, 150 - 2500 lbs, ISO PN 20, 50
Temperature range
-100°C - +300 °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, ISO, others on request
Bottom support
for larger pipe sizes and high velocities especially in gas applications
Mounting
Welding to the pipe
Instrument connection
½" BSP or NPT, Weld ends Ø21,3
Mounting neck
standard lengths, 130, 180 mm, other lenghts available
Technical Data
Accuracy
± 1% accuracy of actual flow
Repeatability
± 0,1%
Reynolds no.
Minimum 100.000 at full flow
Rangeability
10:1
Max. fluid velocity
liquids 5 m/s, gasses 80 m/s
Required straight pipe lengths

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
Maximum allowable differential pressure in bar, without bottom support, with reference to mechanical bend
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