SharpEye 20/20 MI

Triple Infrared In A Compact Housing

Triple infrared detection works by watching several infrared bands at once and comparing them. A hydrocarbon fire produces a strong signal on the channel tuned to hot carbon dioxide, comparatively little on the reference channels, and the flicker frequency characteristic of a flame. A hot surface, a heater or sunlight on metal produces broadly similar output across all three channels and no flicker.

Requiring several views of the same event to agree is what delivers the immunity. It is why triple infrared is specified where false alarms would be expensive or where a detector cannot be allowed to be bypassed.

The 20/20MI brings that to a compact detector for smaller protected areas, where previously the choice was a larger detector than the risk warranted or a technology with weaker rejection.

Eighty Percent Less Power

This is the specification that decides installations rather than the detection performance.

The 20/20MI draws 80 percent less power than comparable detectors. On a mains powered plant that is a footnote. On a solar powered remote site, a battery backed system or an installation where the loop budget is already committed, it is the difference between the detector being possible and not.

It also compounds. A lower draw per detector means more detectors on one supply, smaller cable, and a smaller solar array or battery bank. On a remote wellhead or an unmanned asset, that is a materially cheaper installation.

Sensitivity You Can Select

Sensitivity is selectable, and functions are user programmable through software from a PC or a handheld device.

That matters more on a short range detector than a long one. A detector covering a small enclosure sits close to the hazard, so the same sensitivity that suits a 30 metre open bay will be over-responsive at three metres. Being able to set it on site means the detector is tuned to the area rather than to a default.

General Purpose Or Intrinsically Safe

The 20/20MI is available in two forms. A general purpose non-Ex approved version for unclassified areas, and an intrinsically safe Ex ia version for classified ones.

The intrinsically safe route is worth understanding. Rather than containing an explosion, an Ex ia detector limits the energy in the circuit so an ignition cannot occur. That requires a matched barrier or galvanic isolator in the safe area, and the certification applies to the loop rather than to the detector alone. Gastech supplies the barriers and verifies the loop as part of specifying it.

For a small classified area such as a pump skid or a sample house, an intrinsically safe compact detector is often a simpler installation than a flameproof one, because the cabling and glanding requirements are lighter.

What It Will Not See

Worth stating plainly, because it saves a wrong purchase.

Triple infrared detects fires through the carbon dioxide their combustion produces. Hydrogen contains no carbon and burns to water vapour, so a hydrogen fire produces no signature on these channels and the detector will register nothing. Metal and inorganic fires produce neither signature.

Where hydrogen, metals or inorganic materials are part of the risk, the SharpEye 20/20ML is the compact alternative, combining ultraviolet and infrared to cover all of them at up to 15 metres.

Integration

Connection is a standard four wire arrangement. Analogue output is 4 to 20 mA in sink or source, three or four wire, and RS-485 Modbus is available for digital integration.

Built in test runs automatically and can be triggered manually. Mean time between failures is quoted at a minimum of 100,000 hours, with a three year warranty.

Approvals held include FM, ATEX through SIRA, DNV and ABS, which covers land based industrial installation through to marine and offshore.

Where It Is Used

Pump and compressor skids. Small process enclosures and cabinets. Remote wellheads and unmanned assets on solar or battery power. Sample and analyser houses. Generator and plant rooms. Fuel dispensing and small storage areas. Turbine enclosures. Machinery spaces on vessels and offshore installations. Loading racks and transfer points. Small tank farms and bunded areas.