Intrinsically safe instrumentation is generally preferred over explosion proof equipment because there is not enough power present to create an ignition source. Illinois Instruments offers intrinsically safe instrumentation for measuring either process oxygen or trace moisture.  The oxygen intrinsically safe instrumentation is our Model EC91.  When powered through approved safety barriers, the oxygen analyzer is intrinsically safe.  We also have our Model 400 Moisture Analyzer that can be supplied with a remote intrinsically safe sensor.

All intrinsically safe instrumentation needs to be powered through approved safety barriers.  The zener barriers limit the voltage to the intrinsically safe instrumentation so that it cannot be a source of ignition.  Barrier/power supply packages are available from Illinois Instruments.

Illinois Instruments' EC91 Intrinsically Safe Instrumentation detects oxygen levels from .01 ppm to 21.0% and can be used in most industrial gases and atmospheres. The instrument requires no periodic maintenance such as replacing electrodes or electrolyte and is easily calibrated using ambient air or standard calibration samples. The enclosure is molded of glass fiber reinforced polyester, an impact resistant material unaffected by oils, common acids, and alkalies. A wide door is fitted with stainless steel hinge pins making it suitable for harsh environments and protected to IP67 standards.

The Model EC91 can be wall or post mounted and transmits a 4-20mA signal corresponding to the oxygen level. The unit may have up to six ranges and has an LCD for local indication. An optional control room display and alarm unit is also available. All electronic circuits are intrinsically safe and have been certified to BASEEFA and CENELEC standards. Connections to safe areas must be fitted with shunt diode safety barriers.

Features:

	Insensitive to sample flow rate
	Maintenance free disposable measuring cell
	Six selectable ranges cover ppm and percent levels
	Air calibration check
	Rugged construction unaffected by orientation or vibration
	Simple to operate
	Specific to oxygen

Applications:

	Inert atmosphere gas blanket monitoring
	Quality control (gas mixing and manufacturing)
	Cryogenics/Glove boxes
	Gas purity certification
	Microbiology/Biotechnology
	Metallurgy
	Safety applications
	Gas line monitoring