Figure 4-44.—Gems TLI system.
Depending on the size and shape of the tank
being gaged, the transmitter assembly may be a
single unit, or a number of units connected together.
Figure 4-45 shows two transmitters being used to
gage a tank.
The magnet-equipped float moves along the
transmitter as the liquid level changes. As the float
moves. the magnetic field pattern of the float operates
the tap switches. The tap switches are so arranged
inside the transmitter that voltage drops are read at
the receiver for each 1/2-inch of float travel.
The primary receiver is connected to the
transmitter by the cable system. Since the receiver
meter indicates the voltage drop from the bottom of
the voltage divider to the point of tap switch closure,
the readings correspond directly with the liquid level.
Included in the primary receiver housing, in addition
to the indicating meter, are the dc power supply,
electrical slosh dampening control, and all system
and alarm controls.
Figure 4-45.—Multitransmitter arrangement.
See figure 4-46 for the various types of primary and
secondary receivers.
The primary receiver also provides for
connection of one or more secondary receivers. The
secondary receiver, if used, contains an indication
meter only.
The system is safe, since currents in the
transmitter circuit are so low as to be incapable of
causing an explosion, even with the transmitter
located in the most volatile liquids or hazardous
vapors.
CAUTION
The transmitter or receiver should NOT be
tampered with or modified in any way other
than as directed in the operation and
maintenance manual.
The following is a brief description of the system
controls.
ON-OFF-FULL REF. TOGGLE SWITCH: Oper-
ates as follows to control the ac input to the power
supply and the indicating meter circuit:
Toggle in ON position (normal operation): 115
volt, 50/60 Hz applied to the power supply. Indicating
voltmeter connected through series resistance to the
transmitter tap switches.
Toggle in OFF position: Power supply line and
indicating meter circuits are open. System is off.
4-54
