MSA Senscient ELDS Open Path Gas Detector

Descriptions of MSA Senscient ELDS

• The Senscient ELDS 1000 / 2000 Series is a range of open path, flammable and / or toxic gas detectors that is currently available in the following versions.
  • Senscient ELDS Series 1000 CH4- Methane Detector
  • Senscient ELDS Series 1000 Ethylene, HCl, NH3 or CO2 Detectors
  • Senscient ELDS Series 1000 XD – Cross Duct Methane Detector
  • Senscient ELDS Series 2000 H2S – Hydrogen Sulfide Detector
  • Senscient ELDS Series 2000 CH4 + H2S – Simultaneous Methane & Hydrogen Sulfide Detector
• The Senscient ELDS Series 1000 detector consists of a Transmitter unit that sends an infrared laser beam to a separate Receiver unit that can be installed on a line-of-sight at a distance of up to 200m. The ELDS 1000 Series CH4 detector can be located where there is a risk that a leak of flammable methane gas may occur, to provide a rapid, early warning of such a hazard. The ELDS 2000 variants are similar, except that there are two coinciding infrared laser beams, which can either be used to detect two or more gases, or to detect a single, difficult gas with high sensitivity (e.g. Hydrogen Sulfide)
• All ELDS gas detectors operate on the principle of absorption of infrared laser light. Gases absorb light at specific wavelengths depending on their molecular composition. Hydrocarbon gases such as methane and ethylene absorb in the infrared region of the spectrum. If a cloud of target gas is present, the specific wavelengths of the infrared laser light output by the ELDS™
• Transmitter are absorbed by the gas, introducing Harmonic Fingerprints onto the signals reaching the Receiver that are proportional to the amount of gas in the beam.
• The Senscient ELDS™ Transmitter unit produces the precisely controlled infrared laser light required to detect the target gases; whilst the Receiver unit contains an infrared detector and advanced signal processing electronics which look for the Harmonic Fingerprint produced by the presence of target gas in the beam-path. Each unit is housed in a robust 316L stainless steel housing. The Receiver features two 4 – 20mA analogue outputs which are used to signal the quantity of each target gas measured in the beam-path, for example 0-1LEL.m CH4 and 0-250ppm.m H2S for the Series 2000 detector. These outputs provide a linear relationship with the measured gas burden.
• Note that open path detectors do not measure the point concentration of the target gas(es), rather they measure the integrated concentration over the length of the measurement path between the Transmitter and Receiver units. This means that the probable size of a gas cloud must be considered when estimating the concentration of gas that might be present, with alarm levels being set accordingly. The figures on the following page illustrate this.

Technical specifications of MSA Senscient ELDS