Span Calibration - Toshiba LQ500 Operation Manual

6 F 8 A 0 5 2 1

6.5 Span Calibration

Span calibration is for adjusting the readings of the density meter to the values determined by
manual (off-line) analysis.
For information on the converter operation and the LCD display regarding span calibration, please
refer to Subsection 5.2.12.
(1) Preparations for manual analysis
Prepare following items for manual analysis; a moisture meter (for example, an infrared moisture
meter, with the accuracy or percentage reading down to 0. 1 %), plastic bottles of about l liter with
a wide opening, and plastic beakers of about l00 ml for manual analysis.
(2) Sample fluid for manual analysis
Slightly open the sampling valve on the pipeline and let out the fluid a while before filling a 1-liter
bottle to half. Read and record the density value of the current fluid.
◆ Make sure to carry out the sampling when the density of the measured matter is in a
[NOTE]
stable state with the measured matter flowing.
(3) Manual analysis
Put a part of the sample fluid into a 100-ml plastic beaker, and measure the density of it using drying
and weighing method of analysis.
(4) Calculation of density multiplier
Use the result of analysis to calculate a density multiplier using the following equation after the
manual analysis conducted:
Density multiplier C = A/(M/C
'
(Initially, C is equal to 1.000 which is the value set in the factory before shipping)
For example, if M = 4.0 ％TS, A = 4.8 ％TS and C
◆ In the case that span calibration has been done already, and density multiplier C is not 1.000, the
new density multiplier C can be calculated in the following way.
For example, if M = 4.8 %TS, A = 4.2 %TS and C
where M is the density by the density meter (as read and recorded);
A is the result of the manual analysis
'
C is the density multiplier before span calibration
C = 4.8 / (4.0/1) = 4.8/4.0 = 1.2
C = 4.2 / (4.8/1.2) = 4.2/4 = 1.050
 62 
'
)
'
=1.000
=1.2
0