Page 12
Isoil impianti SpA
Code MA/038/00/EN/03
All rights reserved. Reproduction of this manual is forbidden
4.2.1 Calibration of flow meter
The calibrating mechanism comprises a train of gears which transmit movement of the
rotor to the counter. Operational failures of the mechanism are rare and they generally
regard the breaking of tension pin, due to an excessive strain.
It is recommended to repair without varying the calibrating adjustment.
Attention: do not remove the shimming washers between the frame and the bearing of the
mechanism box.
To carry out meter calibration follow next procedures:
•
Break and remove seals.
•
Remove the three screws (1) securing the cover (2) to the housing (3) in which
calibrating mechanism is fitted.
•
Remove cover (2)
•
By using square key (4 mm) turn shaft (4) till A, B, C holes placed on the bracket (5)
and on friction roller (6) will be properly aligned.
•
Insert in these holes the stop pin (supplied with the meter, then using the square key
operate on the shaft (4) as follow :
- turning counter-clockwise direction, even if the quantity of fluid does not vary, on
the counter is obtained an higher volume indication;
- turning clockwise direction it is obtained a lesser indication.
NOTE:
one complete turn of the screw varies the volume indicated on the meter by
approximately 0,36% (per cent).
4.2.2 Suggested lubricating oils for calibrating mechanism
Company
Type
Temeprature range
AGIP
OTE 32
SINT 2000
-10
÷
+60 °C
ESSO
NUTO 32
-20
÷
+65 °C
IP
HINDRUS HI 46
-10
÷
+60 °C
SHELL
AEROSHELL FLUID 31
-40
÷
+204°C
MOBIL
DTE 26
MOBIL 1
-10
÷
+80 °C
-10
÷
+200 °C
NOTE:
to avoid ice forming in wintertime, add two spoons of car antifreeze.
4.3 Tests after overhaul
After overhaul the p.d. meters must be tested with suitable proving systems. Error between
the value stated by the p.d.meter counter and the value stated by the proving device is
calculated as below:
Example:
Measured by the meter
Measured by the proving tank Error (%)
1000 l
1003 l
-0,3%
1000 l
997 l
+0,3%
The formula is: