MFC
Functions
4.
85
Determining the controlvariable
independent
dead time Tconst
The control variable independent dead time Tconst consists of the
measuring dead time and the dosing dead time.
Calculating the measuring dead
time
Calculation 1:
The sample water is extracted right after the mixture loop and fed
to the measuring cell.
The sample water dead time depends on the nominal diameter
and length of the sample water line and the flow rate to the
measuring cell. A flow rate of 36 l/h is assumed for the
DEPOLOX
®
5 measuring cell.
The following equation applies to the DEPOLOX
®
5:
t
mw(DEPOLOX® 5)
= (d
mw
x d
mw
x l
mw
) : 7.65 (result in min)
In general, this equation applies:
t
mw
= (4.71 x d
mw
x d
mw
x l
mw
) : Q
mw
(result in min)
d
mw
=
Internal diameter of the sample water line in cm
l
mw
= Length of the sample water line in meter
Q
mw
=
Flow rate to the measuring cell in l/h
Example
As a DN6 the sample water line is 10 m long and connected to a
DEPOLOX
®
5 chlorine measuring cell.
t
mW
= (0.6 x 0.6 x 10) : 7.65 min = 0.47 min, (i.e. approx. 28 sec.)
Calculation 2:
The sample water is extracted using an additional sample water
pump (bypass line).
Sample water dead time depends on the flow rate of the sample
water pump, nominal diameter of the bypass line and its length up
to the sample water branch pipe to the measuring cell.
T
by
= (4.71 x d
by
x d
by
x l
by
) : Q
by
d
by
=
Internal diameter of the bypass line in cm
l
by
=
Length of the bypass line from the sample water
extraction point
to the sample water branch pipe to the cell in m
Q
by
=
Flow rate to the bypass pump in l/h
(result in min)
Check whether the length of the sample water line to the
measuring cell can be neglected. If so, establish the sum from
calculation 1 and 2.
Содержание WALLACE & TIERNAN MFC
Страница 1: ...WALLACE TIERNAN MULTI FUNCTION CONTROLLER MFC from version V 2 00 INSTRUCTION MANUAL...
Страница 2: ...2 WT 050 580 000 DE IM 0714 MFC Please note Original manual...
Страница 6: ...6 WT 050 580 000 DE IM 0714 Introduction MFC 1...
Страница 40: ...40 WT 050 580 000 DE IM 0714 Description MFC 3...
Страница 225: ...MFC Complete Devices Retrofit Kits and Spare Parts 8 225 DEPOLOX 5 drawing non pressurised version W3T170031 W3T170031...
Страница 229: ...MFC Complete Devices Retrofit Kits and Spare Parts 8 229 DEPOLOX 5 drawing pressurised version W3T170032 W3T170032...
Страница 233: ...MFC Complete Devices Retrofit Kits and Spare Parts 8 233 VariaSens drawing non pressurised version W3T158742 W3T158742...
Страница 237: ...MFC Complete Devices Retrofit Kits and Spare Parts 8 237 VariaSens drawing pressurised version W3T158756 W3T158756...
Страница 247: ...MFC Certificates 10 247 10 Certificates...
Страница 248: ...248 WT 050 580 000 DE IM 0714 Certificates MFC 10...
Страница 249: ...MFC Certificates 10 249...
Страница 250: ...250 WT 050 580 000 DE IM 0714 Certificates MFC 10...
Страница 262: ...262 WT 050 580 000 DE IM 0714 Settings table MFC 11...
Страница 266: ...266 WT 050 580 000 DE IM 0714 Index MFC 12...