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APPENDIX A
The bulb and bellows assembly is completely filled with
a liquid having the proper expansion characteristics.
The bulb is immersed in the metered liquid and the
bellows is attached to the controlling arm of the
calibrator. Temperature changes in the liquid being
measured act upon the liquid in the temperature
compensating bulb causing expansion or contraction of
the metal bellows which actuates the calibrator arm,
automatically correcting meter measurement to 60 F.
While the liquid contained in the temperature correcting
bulb is affected solely by the temperature of the product
being metered, the small amount of the same liquid
contained in the metal bellows is affected by the
ambient temperature. To correct for any error due to
movement of the bellows as a result of a change in
ambient temperature, the bellows is built into an
assembly including a second bellows containing a
volume of liquid equal to the first.
The bellows assembly is arranged in such a manner that
while a rise in ambient temperature will cause both
bellows to expand, the lengthening of one bellows tends
to lengthen the whole bellows assembly while the
lengthening of the other tends to shorten the assembly
by the same amount, nullifying the effect of ambient
temperature
on
the
bellows.
This
makes
the
temperature correcting device responsive only to the
effect of the temperature of the product being
measured, acting on the liquid in the temperature
correcting bulb.
METER CALIBRATION
Meter calibration can be made by use of the calibrator
dial which is revealed by removing the calibrator access
cover, Figure 18, located immediately below the
register. The amount of product delivered through the
meter increases when the calibrating dial is turned in a
clockwise direction and diminishes if the dial is turned in
a counterclockwise direction. The dial is graduated to
provide increments of adjustment approximately 1/20 of
1%. ( 4 ounce in 50 gallons or 6 cubic inches in 50
gallons to each notch.)
FIG. 17.
A9-29
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