INSTALLATION

Meter installation is critical to proper operation and flow measurement for Doppler and Transit Time flow technologies. Since process piping is both the flow containment and measurement spool piece, care must be taken in location selection, mounting orientation and mounting method.

TRANSDUCER LOCATION SELECTION

With regard to location selection and mounting ori- entation, care must be exercised to establish a point in the piping system that meets the following criteria:

• Choose a section of pipe that is always full
  
  
• Site should meet straight run requirements of at least 10 diameters upstream and 5 diameters down- stream. (Figure A)
  
  
• After a pump, control valve or double piping bend, up to 30 diameters of straight run may be required.
  
  
• On horizontal pipe, mount transducers in the 3 and/or 9 o’clock position (see mounting method). This avoids sediment that may collect on the bottom of the piping and bubbles or air pockets along the top of the piping, which can cause signal loss.
  
  
• Ensure pipe skin temperature is within transducer temperature rating (see specifications).
  
  
• If possible select a section of pipe where inside and outside are free form excessive scaling or corrosion.
  
  

If any or all off the above guidelines cannot be followed completely, it is still possible to obtain meaningful flow measurements, often with little or no loss of accuracy.

TRANSDUCER MOUNTING METHODS

With regard to mounting methods there are four configurations, one for Doppler and three for Transit Time. Each will be discussed and illustrated separately.

Doppler has one mounting method which has the traducer mounted directly across (180°) from each other on the piping.

Transit Time has three mounting methods that are typically chosen on the basis of the piping diameter.