1 Introduction
Manual TRZ 03· EN08 2018 September, 10th
22
1.11 Pressure loss
The pressure loss of RMG turbine meters has been reduced to a minimum thanks
to modifications with regard to design. The measuring points for pressure loss are
located 1 x DN upstream and downstream of the gas meter. The pressure loss is
calculated using the following formula:
where:
p pressure loss
[mbar]
Z
p
pressure loss coefficient
m
density
[kg/m³]
Q
m
volume flow rate at measurement conditions
[m³/h]
DN is the nominal diameter of the gas meter
[mm]
Device type
Z
p
Turbine meter TRZ 03 / TRZ 03-K
3000
Turbine meter
TRZ 03 / TRZ 03-K
G4000-45 DN300
G6500-45 DN400
3500
L1 perforated-plate straightener as per ISO/DIN
3150
L2 perforated-plate straightener as per ISO/DIN
6300
L3 perforated-plate straightener as per ISO/DIN
9450
LP-35 perforated-plate straightener as per RMG-Norm
1260
RB 19 tube-bundle straightener as per ISO/DIN
1260
The values for Zp are approximate mean values. The exact value is calculated
from the pressure loss, which is determined during testing the turbine meter.
Example of calculation
of the pressure loss for a turbine meter with upstream
perforatedplate straightener:
TRZ 03 in DN 150:
Q
m
= 650 m³/h
m
= 1,3 kg/m³ (natural gas)
From the table on the previous page you may find:
Z
p
(TRZ 03)
= 3000
Z
p
(LP-35)
= 1260