7.1 - Process Site Selection
56
SBT-2400 Appendix
M2041/5en
©BTG 2006
7.1.1
Straight Pipe Length Calculation
The nomogram in Fig 2 shows the recommended lengths of straight pipe at dif-
ferent operating flow velocities and consistency levels when a chemical pulp is
in use. Multiply the relative length (L/D) with the tube diameter (D) to get the
minimum length.
For mechanical pulp, the straight pipe length must be multiplied by 1.25.
Straight pipe length formula:
L
B
= L/D x D x Ic x Mp
L
A
= 0.5 x L
B
L
D
= L
B
or more
Explanation of variables:
L
B
= Straight pipe length upstream of the transmitter
L
A
= Straight pipe length downstream of the transmitter
L
D
= Length before transmitter in double bend scenario
D = Pipe diameter
V = Pulp velocity
Cs = Pulp consistency in percent
L/D = Relative length (from the nomogram)
Ic = Installation constant (For horizontal installation Ic = 1.5, for
vertical installation Ic = 1)
Mp = Pulp type constant
(For chemical pulp Mp = 1, for mechanical pulp Mp = 1.25)
Required Length
Fig
2 Nomogram
