BTG Pulptec SBT-2400, Руководство пользователя

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7.4 - Dimensioning of the Dilution Water Valve
66 SBT-2400 Appendix M2041/5en
©BTG 2006
When the dilution water density normally is 1000 kg/m³ the formula can be sim-
plified to:
The pressure of the dilution water should not vary more than 15%. In case of
large pressure variations we recommend pressure control of the dilution water.
EXAMPLE:
In a traditional installation as shown in Fig 11, dilution water is injected before
the pulp pump and the pressure drop across the control valve is equal to the
difference between the dilution water pressure and the height of the pulp
chest. The minimum pressure difference should be 0.4 - 0.5 bar / 6 - 7.5 psi.
In this case the pressure difference is 0.8 - 0.3 bar = 0.5 bar / 12 - 4.5 psi = 7.5
psi. Using the same data as in the examples above, the required Kv will be:
Choose a valve size 40 or 50 mm (1½ or 2 in) depending on the pipe dimen-
sion.
The velocity of the dilution water at the point of injection should be 3 - 5 m/s (10
- 16.5 fps). According to the nomogram in Fig 12 a pipe size of 60-80 mm (2.5
- 3.2 in) is a suitable dimension.
K
v
Q
p
Δ
----------- =
Fig 11 Example of traditional
dilution before pulp
pump
K
v
Q
p
Δ
-----------
53,3
0,5
----------- 75,4 = = =