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USING the Maximus™
Overfill Diagnostic Instrument / Continuous Level Gauge (ODI/CLG)

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The ODI/CLG Project:

The need to accurately and quickly assess the performance of the internal automatic stop-fill device (commonly called an Overfill Prevention Device, or an OPD) or any other condition that may cause the unsafe overfilling of a propane on-board cylinder is critical for vehicle safety. With the Maximus™ Overfill Diagnostic Instrument (ODI), the level of propane in a cylinder can be quickly determined, and not just at the 80% full point (the maximum fill point of a cylinder when using LP Gas) as it is currently limited by the maximum fixed liquid level gauge which is positioned at ~80% full. In the past, it was necessary to keep open the Fixed Maximum Liquid Level Gauge (FMLLG), or “Outage Gauge”, or “Spitter Valve” throughout the refilling process. That is no longer necessary if the Overfill Diagnostic Instrument (ODI) is used at appropriate intervals (at least twice per year for vehicles that are older than three years), to verify the proper functioning of the OPD or any other malfunction that may cause the on-board cylinder to be overfilled. It is important to note that the use of the Maximus™ Overfill Diagnostic Instrument avoids any LP Gas being released to the atmosphere through the FMLLG or through the Pressure Relief Device (PRD).

The ODI instrument operates in either of two modes:  
  - Overfill Diagnostic Instrument (ODI)
  - Continuous Level Gauge (CLG)

In ODI mode, the liquid level is located by moving up and down (like using a stud-finder) a specially designed sensor head on the surface of the cylinder. Since sound travels poorly through vapor space the operator can quickly find the line of the liquid-vapor interface (i.e. the fill level). The first video below shows how to properly use the instrument in ODI mode.

In CLG mode, the device also uses ultrasound, but with the sensing head mounted in a stationary position on the bottom surface of the tank. The sound moves up through the liquid until it reaches the liquid-vapor boundary. At that point it bounces back to the sensor head. The CLG then calculates the fill level based on the operator-entered data about the cylinder's wall thickness and diameter. The second video below shows how to properly use the instrument in CLG mode.

The two modes may be used separately or in tandem. In some installations, only one mode may be usable due to the way the cylinder is mounted in the vehicle.

For Additional Information:

Mr. Alex Spataru
ASCENT Sciences
51 Rover Blvd.
Los Alamos, NM, 87544
PH: (505) 672-0002

Download Operating Instruction Manual


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