7.1 - Process Site Selection
M2041/5en
SBT-2400 Appendix
59
©BTG 2006
7.1.4
Multiple Bend Piping Installation
If there are multiple bends upstream of the transmitter, then the L
D
must be
equal to L or longer. If not, flow guides must be installed.
Two successive pipe bends can also create as twisting flow that cannot be
straightened, even if the recommended straight sections are used.
Calculation example for pipe with multiple bends
D = 200 mm
Cs = 3.5%, chemical pulp
V = 2.4 m/s
The nomogram shows a relative length (L/D)
7.5. The Mp constant is 1
and the Ic constant is 1.
L
B
= L/D x D x Mp x Ic
L
B
= 7.5 x 200 x 1 x 1 = 1500 mm.
L
A
= 0.5 x L
B
L
A
= 750 mm
L
D
= L
B
or more
L
D
= 1500 mm or more
The recommended length upstream of the transmitter is 2250 mm and the
recommended length downstream of the transmitter is 1125 mm. The
recommended
L
D
value must be 1500 mm or more.
≈
L
B
L
A
L
D
L
B
L
A
L
D
Fig
5 Multiple bends
scenario
