4
chamber so that the liquid entering the fluid line flows uphill). Remove the plug from the chamber valve below
the last chamber, open the filling valve and allow the liquid to slowly fill the liquid line. When the liquid line is
full the plug at far end of the line can be replaced.
2.6 The chambers should now be filled,
to approximately mid-height on the weight. This is the recommended starting point. Start filling by opening the
valve on the chamber that is closest to the supply. Allow the liquid to come to approximately the 1/2 filled
position as viewed on the chamber site tube. The limits of the range are marked on the chamber site tube. Close
the valve. Go to the next chamber in line and repeat this operation.
When all the chambers have been filled to this level and closed off, go to the filling valve and close it. Now open
all of the chamber valves and allow the liquid level to equilibrate in all the chambers. If any chamber is seen to be
either to high or too low it should be adjusted now, using the threaded rod mounts if possible. If this is not
possible the mounting bracket may need to be moved. The system liquid level can now be adjusted by adding or
removing liquid through the filling valve. When the proper level is achieved the valve is closed and the supply
reservoir can be disconnected. To prevent tampering with the liquid level the handle should be removed form the
filling valve. The plug on the end of the chamber vent line at the first chamber can now be replaced. The
desiccant chamber can be attached to the open end of the transducer vent line. The sensor operation should be
confirmed now by taking readings on all sensors and calculating the submersion of each sensor. This is
accomplished by taking the change in output of the gage from the zero reading, (R0) with the weight hanging in
air, and the current reading with the weight submerged and multiplying by the gage factor. The gage factor and
zero reading, (R0) are shown on the calibration sheets. (See Appendix B, Page 10). The result should match,
approximately, the position of the water in the sight tube on the chamber.
3. Calibration
Laboratory calibrations are performed on each individual sensor using a system of calibrated weights. Gage
factors are presented for pure water applications. If mixtures other than this are used, the gage factor should be
adjusted for the specific gravity of the fluid used.
4. Taking Readings
The Model 4675 is read using the GK-401, GK-403 or GK-404 Readout Box in Position ‘B’.
The change in elevation for any particular chamber in a system is determined as follows:
∆
EL
x
= (R
1
x
– R
0
x
) G
x
– (R
1
Ref
– R
0
Ref
) G
Ref
where:
∆
EL
x
= Change in Elevation for Chamber x
R
1
x
= Current Reading Chamber x
R
0
x
= Initial Reading Chamber x
G
x
= Calibration Factor Chamber x
