Therefore, the use of the secondary sight port becomes an important part of
normal operations.
5.4.3 When tape motion is stopped, the tape reading seen in the “secondary” sight port
is exactly 300MM above “zero” ullage reference level.
CAUTION:
If the gauging tape reading seen at the secondary sight port is to be used as a
recorded ullage, 300MM must be subtracted from reading to correct the
“zero” ullage reference plane.
5.4.4 In addition to the above functions, the secondary port provides an easy means of
determining oil-water interface layer measurements. Ince interface measurements
are only concerned with relative differences, the previously mentioned 300MM
corrective subtraction becomes unnecessary.
5.5
TAPE OVER-WIND AND OTHER CONSIDERATIONS:
The closed gauging tape is provided with an automatic anti-wind mechanism. The
purpose of this mechanism is to prevent the operator from re-winding the tape, after
having fully payed-out the tape length, in an opposite fold over sense. When a tape is
fully extended, a hard stop to further tape reel rotation will occur. Do not force this stop,
as tape damage may result. When a tape travel stop is encountered, please observe the
tape re-wind level for the proper re-wind direction.
Internally, spring band fingers have been positioned around the tape take-up reel, to
prevent the tape from coming out of the reel. However, in the event that the assembly is
inadvertently dropped a good distance with a tape not fully rewound, the gauging case
cover should be removed for an internal inspection.
5.6
SIGHT PORT GLASS CLEANING:
Occasionally, sight glass cleaning may become necessary. With reference to drawings A-
2562-146 and A-2562-147, cleaning may be easily accomplished. Cleaning may be most
easily accomplished by unscrewing the entire assembly and washing in a suitable
detergent.
CAUTION!
To maintain the sealed integrity of the gauging assembly, be sure that the case seal “O”
ring, Part No. 5 is in place upon re-installation of sight ports.
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