Explosion-proof, Intrinsically Safe, Ground and Continuity Control
Series TR-7 Safe-T-Ground provides continuous monitoring of a
truck's ground connection throughout loading operations. Static electricity
is often brought in by tank trucks entering the loading area. The Safe-T-Ground
Series TR-7 instantly stops loading operations if a tank truck loses its
ground. The simple but rugged Series TR-7 circuit continuously measures
resistance through the truck by applying a small voltage to one terminal
of the truck grounding contactor. The other terminal is connected to
the loading rack ground. If the Safe-T-Ground detects a resistance of
more than a few ohms across the contact terminals, the relay opens, breaking
the control circuit. The relay will not close until the grounding contactor
is properly connected.
To safeguard loading operations, the Safe-T-Ground circuit can be wired
into your pump control - and to an audible alarm or signal light.
The double wire TR-7 system provides an extra safeguard against explosion,
compared to single wire grounding, which cannot measure the quality of
the electrical ground connection durring loading. The transistorized
TR-7 circiut generates little heat - an added safety feature.
The Series TR-7 Safe-T-Ground is simple and easy to install. Removal
of the cover on the explosion-proof aluminum housing reveals the easily
accessable terminal strip for relay and ground control wiring, and a
complete schematic wiring diagram appears on a label next to the terminal
strip for easy wiring. Coiled grounding cable/contactor-handle assembly
is easily replaced via mil-spec connector on housing.