RABO
®
Rotary Gas Meter
07 Elster Instromet
b) Sizing Chart
Using the chart below, select the appropriate meter by using the Maximum Instantaneous Flow Rate (scfh) and the Minimum
Operating Pressure (psig) at any given point in time.
Example: A flow rate of 25,000 scfh and an operating pressure range of 75–100 psig would require a 5.5M meter based on a
75 psig minimum inlet pressure.
Model
3.5M/G65
5.5M/G100
9M/G160
14M/G250
psig [Barg]
Corrected Capacity in scfh [sm
3
/h]
0.25
[0.0]
3,500
[100]
5,500
[160]
9,000
[250]
14,000
[400]
2
[0.1]
3,900
[110]
6,100
[170]
10,000
[280]
15,600
[440]
5
[0.3]
4,600
[130]
7,200
[200]
11,900
[340]
18,400
[520]
10
[0.7]
5,800
[160]
9,100
[260]
14,900
[420]
23,200
[660]
20
[1.4]
8,200
[230]
12,800
[360]
21,000
[590]
32,700
[930]
30
[2.1]
10,500
[300]
16,600
[470]
27,100
[770]
42,200
[1,190]
40
[2.8]
12,900
[370]
20,300
[570]
33,200
[940]
51,700
[1,460]
50
[3.4]
15,300
[430]
24,000
[680]
39,300
[1,110]
61,200
[1,730]
60
[4.1]
17,700
[500]
27,800
[790]
45,500
[1,290]
70,700
[2,000]
75
[5.2]
21,200
[600]
33,400
[950]
54,600
[1,550]
85,000
[2,410]
100
[6.9]
27,200
[770]
42,700
[1,210]
69,900
[1,980]
108,700
[3,080]
150
[10.3]
39,100
[1,110]
61,400
[1,740]
100,400
[2,840]
156,300
[4,430]
175
[12.1]
45,000
[1,270]
70,700
[2,000]
115,700
[3,280]
180,000
[5,100]
250
[17.2]
62,800
[1,780]
98,700
[2,790]
161,500
[4,570]
251,300
[7,120]
290 [20.0]
72,300
[2,050]
113,700
[3,220]
186,000
[5,270]
289,300
[8,190]
Note: All capacities based on 14.4 psia atmospheric pressure, 14.73 psia base pressure, and 60°F base temperature.
a) Performance
Units
3.5M/G65
5.5M/G100
9M/G160
14M/G250
Rangeability
90:1
160:1
160:1
160:1
Start Rate
acfh [am
3
/h]
1.3
[0.04]
0.9
[0.03]
2.5
[0.07]
2.5
[0.07]
Stop Rate
acfh [am
3
/h]
1.1
[0.03]
0.8
[0.02]
1.9
[0.05]
2.3
[0.07]
Flow Rate at ½" w.c. DP
acfh [am
3
/h]
2,715
[77]
4,074
[115]
5,722
[162]
6,740
[191]
Differential Pressure at 100% Flow Rate
in. w.c. [mBar]
1.46
[3.64]
1.23
[3.06]
1.70
[4.23]
2.65
[6.60]
10. Technical Data
