21 JANUARY 2003
220.127.116.11. Automatic Float Gauge. Figures 7.8 and 7.9 show the type of gauge used on an open-top
floating-roof tank. The gauge is actuated by a float in a well in the deck. The float is connected to
the gauge tape by a stainless steel cable. By connecting the float to the cable with a turnbuckle, it
is possible to make quick adjustments for over-reading or under-reading (lengthen the cable for
under-reading; shorten the cable for over-reading). The tape is counterweighted and both tape and
counterweight are enclosed in a weatherproof housing. The tape is read through a window. The
gauge head (Figure 7.9) uses a spring-actuated storage sheave to take up the tape instead of
counterweights; the tape is passed over a sprocket sheave that registers the liquid level in the tank
on counter wheels for a more accurate reading. On tanks with floating pans, the tape is attached
directly to the honeycomb pan (Figure 7.10). NOTE: This design will not read fuel level below
the setting of the pan legs, and is not a substitute for automatic tank gauging.
Figure 7.8. Automatic Float Gauge.