OMD Optical Methane Detector
The Optical Methane Detector (OMD) is the new mobile leak detector designed and tested in a Gas Research Institute program and manufactured by Heath Consultants Incorporated. The OMD was specifically designed for the mobile inspection of buried natural gas distribution, transmission and gathering pipelines. This new technology combines sensitivity, selectivity and speed through the use of optics and electronics.
Field tests have proven that given ad-equate survey and meteorological conditions the OMD increases productivity 50% or more over current mobile survey. A contributing factor to the increased productivity is the instantaneous response to leak indications versus the time delay present with current flame-ionization technologies. Much of the maintenance associated with flame-ionization units, including moving parts, external fuel gases, outside sources of dust, dirt, moisture and water ingress, is eliminated with the OMD.
The OMD is mounted on the front of a survey vehicle. It employs an infrared (IR) light beam that shines across the front of the vehicle. An optical filter in front of the detector transmits methane IR wavelengths from the light source. In the absence of methane, these wavelengths are afected by small fluctuations in the light beam caused by reasonable amounts of dust, dirt, water or snow. An internal calibration check cell is included so the operator can verify proper operation from the vehicle cab at any time before, during or after the survey, as well as alerting the operator if conditions are not optimal.
Installation on various types of survey vehicles is very simple and can normally be accomplished in a mat- unaffected and produce a steady output signal from the detector. The presence of methane causes a signal, audio and visual, which is transmitted to the display in analog and digital from inside the vehicle. The OMD can detect leak indications in concentrations of less than 1 part per million (ppm) at 10,000 measurements per second. The OMD operates reliably under a variety of environmental conditions including inclement weather, wind and temperatures from -20º F to +110º F. The OMD's sensitivity is not after of hours. All cables are provided with the OMD including the power cable to operate the unit from the survey vehicle's 12 volt battery. An RS232 port is available whereby a personal computer may be connected to acquire and save survey data.
Heath Consultants Incorporated, 9030 Monroe Road, Houston, TX 77061-5212. Tel: 713-844-1300; Fax: 713-844-1309.