Gems Sensors & Controls Relays and Barriers Catalog Page

LECTRONIC PRODUCTS

GEMS Relays and Barriers Render Any
Non-Voltage Producing Sensor or Switch
Intrinsically Safe

 Provide method of eliminating explosive conditions
 Rapid, arc-free response provides positive,

non-mechanical operation

 Solid-state reliability assures consistent performance
 Low-power switching; a few milliamps of current

controls high-power loads

 Completely encapsulated construction

Units are impervious to dust, moisture or foreign material
They are tamper-proof and shock- and vibration-resistant

 Modular housings for easier installation
 Exceptionally long, trouble-free service life

Intrinsic Safety and its Advantages.

Instrument Society of American Specification ISA-RP12.2
Defining Intrinsically Safe Equipment:

“Intrinsically safe equipment and wiring is equipment and wiring which
is incapable of releasing sufficient electrical or thermal energy under
normal or abnormal conditions to cause ignition of a specific hazardous
atmospheric mixture in its most ignited concentration. Intrinsically safe
terminations and wiring may be brought into any hazardous location
of any Group classification for which it is accepted without requiring
explosion-proof housing or other means of protection.”

SOLID STATE RELAYS AND BARRIERS

To be certified “intrinsically safe,” a device or circuit must be so
designed that no two simultaneous failures can cause an explosion.
Intrinsically safe systems are more dependable. The I.S. circuit must
function reliably per specifications, with no explosions, during and after
cycling through a number of operations.

The units can also be installed more conveniently. Since no explosion
is possible, no explosion-proof conduit or enclosures of any kind
are needed in the hazardous area. Maintenance can be performed
immediately as needed. And, intrinsically safe systems are more
economical. Costly enclosures with their mounting requirements are
unnecessary. No purging is required, thereby eliminating blowers,
pressure switches, timers and relays.

®

SAFE-PAK

load-handling capabilities in a wide diversity of AC and DC control
switching applications.

Zener Barriers: These passive, energy-limiting devices, provide
intrinsically safe DC outputs for a variety of sensors such as level and
flow switches…level indicating transducers and transmitters…and
many others. The maximum energy possible at the switch terminals
of the SAFE-PAK and Zener Barriers is far below the explosive point of
the most volatile surrounding gas conditions. The type of non-voltage­producing switch or sensor best suited for the application can be
utilized, since the entire switching circuit is rendered intrinsically safe by
the SAFE-PAK or Zener Barrier. As the switching circuit is low voltage,
there is no shock hazard to operating or maintenance personnel.

RELAYS: These intrinsically safe units amplify sensor