Crowcon - Air Aspirated Sample System

Crowcon - Air Aspirated Sample System

Designed for use in Zone 1 or Zone 2 hazardous areas, the air aspirated system uses a compressed air driven vacuum generator to draw a gas sample from a single point. Explosion proof gas detectors are fitted to monitor for flammable gases, toxic gases or oxygen.

Each detector provides a 4-20mA output. An intrinsically safe flow-fail device warns if the sample flow is lost due to supply air failure or sample line blockage. The system is ideally suited for monitoring flammable gas leaks within turbine enclosures, solvent detection in painting or printing processes or monitoring oxygen levels in industrial processes.

The aspirator system continuously ‘samples’ and is the only system that can be used directly within a hazardous environment. Instead of a pump to draw the sample an educator is used. The eductor is driven by compressed air to create a negative pressure to draw the sample.

The only electrical devices fitted are a sensor and an I.S flow fail device. The detector or flow switch can be wired into a flame proof enclosure. This can be either mounted above the sample cabinet containing terminals and barriers, or directly onto a control panel in a safe area, via any necessary barriers. In the case of a turbine, high temperature gas detectors are often fitted directly within a turbine enclosure. This presents a problem with calibration as the turbine needs to be shut down to allow the engineer access.

The aspirated sample system solution can be maintained without entering an enclosure. This makes the aspirated sample system ideal for gas turbine manufacturers. This is also an ex certified option which can be mounted outside the turbine enclosure (usually an Ex Zone) to keep sample tube runs as short as possible.

This overcomes the main disadvantage of air aspirated systems, which is response time, as the sample flow rate is limited to the maximum the sensor can tolerate: one metre per second.

Key Features

• IP rating: IP65
• Sensor type: Electrochemical, Pellistor
• Outputs: 4-20mA from each sensor plus a flow-fail contact
• Approvals: Certified for use in Zone 1 or Zone 2 hazardous areas
• Gas sensors: 1 per sample line
• Only sampling system that can used in hazardous environments
• Uses an eductor rather than pump
• Only electrical components are the sensor and the intrinsically safe flow fail device.

Sampling Systems can be engineered to suit any application, please Contact Us for prices and system specifications.