Badger Meter Hydrometer - Manual (Page 7)

Section I
Paragraphs 1-30 to 1-37
In addition, a thermometer should be installed as close to the
inlet of the flowmeter as possible. This will provide a
constant check to assure proper flow readings.
e. The flowmeters are calibrated on a Cox Liquid Calibrator
maintaining a 10-15 psig back pressure. Back pressure should
be provided in the installation to aid in purging air out of the
system and introducing float stability.
f. Remove fillister head screws holding end caps to upper end
castings and lift off caps. Remove floats from their container
and wipe them off thoroughly with a clean soft cloth. Notice
that floats are etched with the serial number of instrument and
tube size. Thread the float extractor rod to each float, insert
float in proper tube and lower to bottom of tube. Unscrew
rod. Use care to get floats in proper tube. Install end caps
with their “O” rings and tighten screws. Clearance on panel
cut-out should be provided in the top of any test stand to allow
for float removal.
CAUTION
Do not drop floats into tubes.
1-30. OPERATION.
1-31. GENERAL. The instrument has been accurately
calibrated for a specific liquid or gas and the scales divided
accordingly. Variations in temperature or in specific gravity,
which are marked on edges of scales, will affect correctness of
readings.
1-32. LEAKAGE. The equipment to be tested is normally
connected to the outlet of the instrument. The connections
between flowmeter and equipment must be tight. Any leakage
in this line will result in high readings. If the equipment to be
tested is installed on the inlet side, leakage will result in low
readings.
1-33. EXPEL AIR. Open the bypass valves and provide
means to return the maximum flow to fuel supply tank. Open
supply line to flowmeter and set up rate of flow corresponding
to full scale reading on largest tube, open and close largest
tube valve and allow to remove air. Reduce flow within range
of next largest tube following a bypass valve and repeat
procedure until all air is expelled. Continue in a like manner
until flowmeter is completely purged of air.
CAUTION
Do not operate valves until flowmeter is filled
with liquid. Always leave valve in “OPEN”
position when flowmeter is not in use.
1-34. VALVES. In a multi-stage flowmeter, all valves must
be closed when reading flow in the smaller tubes. As each
valve is opened, the tubes below it are inoperative and
pressure drop is maintained at a minimum. All valves must be
opened when reading last tube.
1-35. READING THE SCALES. Scales are read opposite top
surface of float disc. On units equipped with an orifice, read
the scale on the right side of the largest tube when the orifice
valve is opened. Readings are accurate only when eye of
observer is at the same level as top of float. (See fig. 5.)
1-36. TEMPERATURE. Watch temperature of liquid during
test. Endeavor to keep it within plus or minus 3
qF of value
marked on scale. Three degrees Fahrenheit temperature
change is equal to approximately 0.1% shift in flow rate.
1-37. PRESSURE BLOWOUT DISC ASSEMBLY. If a
flowmeter utilizing a pressure blowout disc assembly has been
subjected to excessive pressure surges causing the blowout
disc to burst, the following procedure must be followed before
resuming operation.
1. Shut down fuel supply to flowmeter
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