Continuous Gas Monitoring for Petrochemical, Coking, Pharmaceutical and Wastewater Sites

Continuous monitoring of flammable, explosive, toxic and harmful gases is the job of the OC-F08 series Fixed gas detector — a wall- or pipe-mounted instrument built for metallurgy, petroleum, chemical, mining, coking, municipal, environmental protection, pharmaceutical, electric power, ship and sewage treatment operations.

These sites depend on continuous measurement rather than spot checks: an instrument has to keep delivering stable readings over long periods, in weather and inside classified areas.

The series covers more than 30 target gases. Toxic gases measured by electrochemical sensors include ammonia at 0-100 ppm with alarm thresholds of 25/50 ppm, hydrogen sulfide at 0-100 ppm with 10/20 ppm, chlorine at 0-50 ppm with 10/20 ppm, phosphine at 0-20 ppm with 0.3/0.6 ppm, and carbon monoxide at 0-500 ppm with 35/70 ppm, alongside hydrogen cyanide, hydrogen chloride, sulfur dioxide, ozone and nitrogen dioxide. Combustible gases are measured in %LEL by catalytic combustion sensors, including methane, propane, ethylene and butane at 0-100 %LEL with 25/50 %LEL thresholds, alongside toluene, xylene, butene and others. Carbon dioxide and methane are also available on NDIR infrared sensors, with CO2 ranges of 0-5.0 %vol and 0-5000 ppm.

Original imported sensors and an ultra-low-power 32-bit microprocessor give the detector high precision, good repeatability, a stable signal and fast response: precision of within 3 %F.S, repeatability within 2 %, zero drift within 1 %F.S per year, and a T90 response time of 30 seconds or less for combustible gas.

For plant integration the detector provides a standard three-wire 4-20 mA output for PLC and DCS systems, with optional four-wire RS485 digital output, 200-1000 Hz frequency output and relay outputs - a two-level relay rated 220 VAC 0.5 A and 5 VDC 0.5 A, and two sets of passive relays at 24 VDC 2 A. Remote monitoring and alarm, data logging and analysis are supported, and signal transmission reaches up to 2,000 m, extendable with a repeater.

Maintenance is addressed through an intelligent, modular sensor design with an independent air chamber: replacing a sensor does not require recalibration, and the detector identifies the sensor's key parameters automatically. An infrared remote control allows checks and configuration without opening the cover in hazardous areas.

The enclosure is die-cast aluminium with a hard alumina air chamber and an IP66 protection grade, with explosion-proof grades of Exd IIC T6 Gb for combustible gas and Exd ib IIC T6 Gb for toxic gas. Operating voltage is 24 V DC with a normal range of 10-30 V DC, and power consumption stays below 1.5 W for toxic gas and below 2.5 W for combustible gas. The working range is -40 to 70 degrees Celsius for combustible gas and -20 to 50 degrees Celsius for toxic gas, at 10-95 %RH non-condensing. Mounting is by wall or pipe with an M40 x 1.5 thread, and electrical interfaces are 3/4 inch NPT and 1/2 inch NPT. The series carries CNEx, CE and RoHS certification and is manufactured to GB15322.1-2003, GB3836.1-2010, GB3836.2-2010, GB3836.4-2010 and GB12358-2006.

With three sensing principles and a gas library of more than 30 substances, the OC-F08 series allows a plant to specify detectors by measured gas, required range and alarm threshold rather than adapting the site to the instrument.

For applications in petrochemical, coking, pharmaceutical or wastewater treatment operations, contact us to discuss the gas to be measured, the required range and the alarm thresholds:

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