Pipe requirements
If the Interference sources (i.e. bends, reduce, valves, T tubes, etc.) exist on the instrument intake pipe, measures must be taken to minimize their impacts on measurement performance.
The following diagrams describe the recommended minimum straightway lengths of some types of pipe.
The straightway length should be as long as possible while the room is sufficient. Without the
consideration of other factors, the recommended minimum straightway lengths are:
front upstream length: 20×DN
back downstream length: 5×DN
- The recommended straightway lengths are minimum, increased straightway lengths improve the instrument performance.
- If multiple Interference sources exist in front of the instrument, the recommended straightway lengths are absolute.
- The control valves are recommended to be placed on a rare instrument.
- For the light gases, such as helium and hydrogen, front straightway lengths should be doubled.
