internal walls defining the measuring chambers are set in rotation and the number of revolutions of these walls represents a measurement of the volume of the gas passed
This Directive applies to the following gas volume meters:
1. Volumetric meters:
- meters with deformable walls;
- meters with rotary pistons.
2. Non-volumetric meters: - turbine meters. ...
The present Chapter applies, together with the provisions of Chapter I, to:
1.1. Rotary piston gas meters
- in which the measurement of gas passed is effected by means of measuring chambers with rotary walls. ...
3.1. Rotary Piston Meters
3.1.1. Meters should include upstream and downstream static pressure tappings of 3 to 5 millimetre diameter to permit measurement of the pressure drop : the pressure measured upstream will constitute the reference pressure.
3.1.2. The meters may incorporate a manual arrangement for turning the pistons provided that it cannot be used in such a way as to interfere with the correct operation of the meter.
3.1.3. The bearings of the shafts of the rotary pistons of meters of sizes G160 and above may be constructed in such a way as to provide access to them without breaking the protective seals.
