Rosemount Tank Radar AB REX 用户手册

TankRadar L/2 equipment is often used in areas where flammable
materials are handled and where an explosive atmosphere may be
present. To protect both the plant and the personnel, precautions
must be taken to ensure that this atmosphere cannot be ignited.
These areas are called hazardous areas and equipment within
these areas must be explosion protected.

A number of different explosion protection techniques have been
developed over the years. Intrinsic safety and explosion proof (or
flame proof) safety are two techniques.

Intrinsic safety, IS, is based on the principle of restricting electrical
energy available in hazardous-area circuits such that any sparks or
hot surfaces, that may occur as a result of electrical faults in com-
ponents, are too weak to cause ignition. Intrinsic safety is the only
technique accepted for Zone 0 hazardous areas. It is also safe for
personnel and allows equipment to be maintained without the
need for a gas-free certificate.

For example, the temperature measurement of the DAUs is intrin-
sically safe.

The basic principles of intrinsic safety are:
-

All flammable materials are grouped according to the energy
needed to ignite them.

-

Equipment located in hazardous areas are classified accord-
ing to the maximum surface temperature that it can produce
and this must be safe with the flammable gases that may be
present.

-

Hazardous areas are classified according to the probability
that an explosive atmosphere is present, and this dictates
whether or not a particular explosion protection technique
may be used.