General Monitor’s electrocatalytic gas sensors are supplied as original equipment on all of our products worldwide. The sensorʼs sensitivity, reliability and longevity make it the first choice for most users of the catalytic oxidation gas detection principle.
The electrocatalytic sensor forms one half of a Wheatstone Bridge circuit where the change in resistance of a platinum coil within a catalyst-impregnated ceramic bead indicates the presence of flammable gas. It achieves the measurement by a proportional change in the resistance of the coil as the coil temperature rises. The other arm of the Bridge circuit is part of the control electronics (either a control card or a field transmitter type), so the two arms must be carefully matched.
It is therefore our policy to supply our catalytic sensors and our replacement sensors only for General Monitor’s equipment. Failure to adhere to this policy can lead to incorrect use and could cause devastating equipment malfunctions.
Every component of our catalytic sensors is manufactured in-house to ensure optimum performance. Careful matching of the active and reference elements (“beads”) yields a sensor with negligible zero drift in response to changes in humidity, pressure, and temperature. Consequently, we can offer sensors that maintain baseline stability over a temperature range of -65°F to 400°F (-55°C to 200°C) and exhibit negligible zero drift over 12 months.
The key design features, along with their corresponding benefits, are summarised below. There are minor design differences according to the approval type and junction box used, but all General Monitors plants and sales offices can provide all types on demand. All have the same outstanding properties and a typical operational life of 3-5 years.
Approvals range from FM to CSA in North America to CENELEC/ATEX and Gosstandart for Europe and Russia.
Sensor bodies are made of corrosion-resistant aluminium alloy or 316-grade stainless steel. A wide variety of accessories is available to provide additional protection against airborne contaminants or for mounting in ducts or sample lines.
Features
- Extra-strong support post.
- Precious metals are used for all components mounted in a Teflon body.
- Active and reference beads matched by size and resistance.
- Teflon barrier protects active and reference beads.
- Glass-coated reference bead.
Benefits
- Protects beads from shock and vibration, avoiding damage.
- Large signal-to-noise ratio for stable performance and long sensor life.
- Eliminates signal drift due to temperature and humidity changes.
- Long sensor life in poisonous atmospheres.
- Eliminates heat transfer, maximising the output signal.
- Eliminates open drift due to reference bead detecting gas.
Order Information
10001-1 General Purpose, Aluminium body, CSA, FM approved
10001-1R General Purpose, Poison Resistant, Aluminium body, CSA, FM approved
10014-1 General Purpose, High temperature to 400°F (200°C), Aluminium body, CSA, FM approved
10014-1R General Purpose, Poison Resistant, High temperature to 400°F (200°C), Aluminum body. CSA, FM
10015-1 Aluminium body, High temperature (max. 120°C) CSA approved
10022-1 Aluminium body, sintered. CSA approved, Group A
10058-1 Stainless steel body, CSA approved
10058-1R Stainless steel body, Poison Resistant, CSA approved
10102-1 Sensor Simulator
10164-1 Hydrogen specific, Aluminium body, CSA approved
11159-1 Stainless steel body, (max. 120°C) ATEX, GOST, CSA approved.
11159-2 Stainless steel body, (max. 180°C) High temperature. ATEX, GOST, CSA approved.
11159-3 Stainless steel body (max. 120°C), super poison-resistant. ATEX, GOST, CSA approved.
11159-1L Stainless steel body, (max. 120°C) ATEX, GOST, CSA approved. (With lugs)
11159-2L Stainless steel body,(max. 180°C) High temperature. ATEX, GOST, CSA approved. (With lugs)
11159-3L Stainless steel body, (max. 120°C) super poison resistant. ATEX, GOST, CSA approved. (W/lugs)
Other Accessories
Portable Purge Calibrator (P/N 1400150-x)
The Portable Purge Calibrator is a compact, accurate and safe system containing no explosive gas. The lecture bottle is filled with a gas/air mixture below the Lower Explosive Limit (Standard mixture is 50% LEL). Using a known gas/air mixture reduces the possibility of error in field calibration, and the hose and cup adapter permits calibration without removing sensors or their attachments.
Sensor Flow Chamber (P/N 10066)
The Sensor Flow Chamber is constructed of aluminium (optional stainless steel) and is designed to be inserted into a sampling system. This allows a sample to be drawn to the sensor when it is not possible to mount it directly in the monitored area. Reasons include: high temperature, pressure, fast airflow, or inaccessibility.
Dust Guard (P/N 10110-1)
The General Monitors Dust Guard Assembly prevents dust and other particulate matter from reaching the sensor flame arrestor and affecting the sensor response. Comprising a simple threaded stainless steel cylinder with a wire screen at one end, the dust guard assembly is easily removed for cleaning or replacement of the disposable screen. The Dust Guard is also available in a kit with twelve disposable screens (P/N 10044-1).
It can act as a windscreen and is recommended for corrosive, windy, or high-temperature environments, with typical applications being in areas surrounding vinyl chloride plants or drying ovens.
Sintered Stainless Steel Dust Guard (P/N 1800822)
The General Monitors Sintered Stainless Steel Dust Guard protects the sensor from fine particulates and is designed for use in windy conditions. It should, however, be used only in dry environments because the sintered disc tends to absorb water and act as a gas diffusion barrier until it dries out.
For accurate calibration, the sensor should be calibrated with the guard in position. In construction, the sintered stainless steel Dust Guard is similar to the Dust Guard Assembly, but has a 3mm thick sintered stainless steel disc at one end with the other end threaded for easy installation.
Splash Guard (P/N 10395-1)
The General Monitors Splash Guard prevents water, in the form of rain or equipment washes, from entering the sensor cavity and affecting the element response, while also acting as an effective windscreen. It is recommended for use in any outdoor environment involving high winds or rain, or where frequent hosing down is practised, such as on offshore platforms. Constructed of rugged ABS plastic and threaded for simple screw-on installation, the Splash Guard has a series of internal baffles to deflect water down and away from the sensor.
Duct Mounting Plate (P/N 10041-x)
The Duct Mounting Plate is ideally suited for mounting sensors to monitor ducted air in the living quarters of large offshore modules.
Remote Test Gas Applicator (P/N 10460-2)
The remote test gas applicator, TGA-1, is designed for permanent installation on a combustible gas sensor. The TGA-1 protects against outside elements and allows the user to apply a test gas to the sensor from a remote source.
Portable Calibration Chamber (P/N 10543-1)
The Portable Calibration Chamber is a practical and safe instrument for the field calibration of combustible gas monitoring systems. Sensors can be calibrated in place with a known liquid/air mixture, reducing the possibility of calibration error. The Portable Calibration Chamber is a 3-litre sample chamber with an intrinsically safe battery-powered mixing fan. For our catalytic bead sensors, a porthole allows the chamber to be placed on the sensor for calibration.
