TERZ 94

7 . Overview
Nominal size Measuring range Pulse value Pressure loss Lubrication
Q min -Q max
LF 1) HF 2) Dp
mm in. m 3/h
pulses/m 3 pulses/m 3 mbar permanently
lubricated
oil pump
25
40
50
1
1½
2
2.5 -
6-
6-
25
70
100
10/100
1/10/100
1/10/100
13450
7800
7800
3
4
5
•
•
•
80
100
150
200
250
300
400
500
600
3
4
6
8
10
12
16
20
24
10 -
25 -
40 -
100 -
160 -
250 -
400 -
650 -
1000 -
250
400
1000
1600
2500
4000
6500
10000
16000
0.1/ 1/10
0.1/ 1/10
0.1/ 1/10
0.1/ 1
0.1/ 1
0.1/ 1
0.1/1
0.1/1
0.01/ 0.1
2375
1060
330
135
75
48
24
12
6
6
4
6
3
3
4
3
4
4
•
•
•
•
•
•
•
•
•
3
4
6
8
10
12
16
20
24
25 -
40 -
100 -
160 -
250 -
400 -
650 -
1000 -
1600 -
400
650
1600
2500
4000
6500
10000
16000
25000
0.1/ 1
0.1/ 1/10
0.1/ 1
0.1/ 1
0.1/ 1
0.1/ 1
0.1/1
0.01/ 0.1
0.01/ 0.1
1250
600
190
80
44
28
14
7
4
14
10
12
8
7
9
8
9
9
•
•
•
•
•
•
•
•
•
1) Standard values (set in the factory) are shown in bold type.
2) Approximate value; the exact value is determined during calibration.
8. Pressure loss
The pressure loss Dp stated in the table applies to natural
gas at Qmax
and 1 bar(a). From this, the pressure loss at
measurement conditions can be calculated in accordance
with the formula below.
Pressure loss as per the formula
Dp
m = Pressure loss at measurement conditions
(p m, Q m) in mbar
Dp = Pressure loss at Qmax
and natural gas at 1 bar
in mbar (see table)
rn
= Standard density of the process gas (kg/m 3)
p m = Pressure at measurement conditions
in bar (absolute)
Q m = Flow rate at measurement conditions (m 3/h)
Q = Maximum flow rate
max
2
rn Qm
• • m •
( Qmax )
Dp m = Dp p
0.83
Example: Air, nominal meter size DN 100, measuring
range 20 - 400 m 3/h, p m = 1.1 bar(abs),
rn
= 1.29 kg/m 3, Q m = 250 m 3/h
take from the table: Dp = 4 mbar
Hence:
2
1.29 250
Dp m = 4 • • 1.1 • = 2.7 mbar
0.83 ( 400 )
9. Measuring accuracy
Measuring error: Qmin to 0.2 · Qmax 0.2 · Qmax to Qmax
DN 25: ± 3% ± 2%
DN 40, DN 50: ± 3% ± 1.5%
DN 80: ± 3% ± 1%
³ DN 100: ± 2% ± 1%
Reproducibility: £ ± 0.5%
10. Maintenance
All turbine meters up to and including the nominal size of
DN 150 are fitted with permanently lubricated bearings
and require no maintenance. From the nominal size of
DN 200, the meters are fitted with a lubricator.
Lubrication has to be performed in compliance with the
operating instructions (see also lubrication instruction
plate on the meter).