Tecfluid CIP II - Manual (Page 5)

5
5. MEASUREMENT ERROR CORRECTIONS
The calibration of the mechanical flow meters is made with water at 20 o C to obtain a
calibration for a liquid of density 1 kg/l and viscosity of 1 mPa·s. If the flow meter is used with
a liquid of other characteristics from the above specified or for reasons of turbulences in the
flow, measurement errors can be induced.
To correct these types of errors we can modify the pulses per litre factor programmed in the
instrument.
Example 1 - Shortage of volume
If we have a flow meter body which specifies i/l = 1.985, and when we check the volume of a
batch, we find that instead of having 100 litres as programmed, we only have 105 litres (5%
more) and we must apply the following correction:
i/l = Original Pulses per litre Factor = 1.985
V = Expected Volume = 100
Vr = Real Volume = 105
i/l n = New Pulses per litre Factor = ? (1.887)
6. CHANGE OF UNITS OF MEASUREMENT
In some cases we need to change the measurement units, for example, instead of working in
litres we need to work in kilograms. In this case we will need to know the density of the liquid
(ρ).
To change from litres to kg we must divide the pulse per litre factor by the density of the liquid
to obtain the new factor for programming the CIP II. For example, if the liquid has a density of
0.9 kg/litre, the meter gives us 200 pulses per litre and we must count in kg, we will program
the CIP II using 222.222 as the new pulses per litre factor to be able to count directly in kg.
Fk = Pulses per litre factor to count in kg
F = Original pulses per litre factor
ρ = Density of the liquid in kg/litre
ρ
F
=
F
k
7. MODELS
CIP II __ __
C COVOL input
T Turbine input
L Local mounting on the flow meter (IP65)
M Remote wall mounting (IP65)