CGT-02 Turbine Gas Meter

The CGT-02 turbine gas meters are flow meters designed to measure quantity of gases. The meters are can be used for gas flow ranges from 5 up to 10 000 m3/h. The CGT-02 gas meters are applied in measurement systems where high accuracy is required:

  • transportation of natural gas
  • primary and secondary measurements
  • control metering of the natural gas and non aggressive technical gases in industry
  • flow measurement for technical purposes
Category:

The turbine gas meter measures the quantity of gas basing on the flow principle. The gas flows through an integrated flow conditioner, which distributes the flow proportionally in the annular slot and guides it to the turbine wheel. The wheel is driven by the gas flow, and the angular velocity of the rotation is proportional to the gas flow rate. The energy consumption, perceived as pressure loss, is reduced to absolute feasible minimum due to the application of the flow conditioner, highest precision ball barings, most accurate tolerances of all measuring parts and their proper alignement. The rotary motion of the turbine wheel is transferred mechanically by gear wheels, and the incorporated gas tight and hermetic magnetic coupling, to the index unit, which is mounted on the top of the body, and shows the operating volume on the totalizer.

The basic components of the CGT-02 turbine gas meter are as follows:

  • pressure resistant meter body
  • inlet flow conditioner
  • measuring cartridge with the turbine wheel
  • magnetic coupling as the transferring element between measuring cartridge and the index
  • index
  • lubricating system (some meters are provided with self lubricating bearings)

The meters are mainly used for measurements of combustible and inert gases. They can be applied for measurements of aggressive  gasses but such applications should be individually proved and agreed between the client and COMMON S.A.

Pressure rating:
 PN10 to PN110,
ANSI150 to ANSI600		 other rates on request
Nominal diameter: DN50 up to DN400 standard range other on request
Meter bodies: ductile iron or steel details in table 4
Flow: 5 to 10 000 m3/h other on request
Rangeability:
 1:20 minimum at atmospheric pressure increased rangeability on request
Upstream pipe:
 minimum 2 x DN; meters meet the requirements of the OIML R32 89 Annex A
Temperature range:
 gas temperature -25°C to +70°C
ambient temperature -25°C to +70°C
Allowed medias: see table 2
Operating position: horizontal or vertical
Measurement accuracy:
 EU requirements and better
guaranteed at least:
0.2 Qmax – Qmax < ± 1%
Qmin – 0.2 Qmax < ± 2%

 

error_curve

Figure 1. Measurement error typical curve at low pressure (average 1 bara) – green curve and at high pressure (over 5 bara) – blue curve

 

Table 1

DN G Maximum Flow
Qmax [m3/h]		 Minimum flow
Qmin [m3/h]		 LF Pulse rate
[m3/pulse]
mm inch
50  2 65 100 5 10
80 3 100 160 8 1
160 250 13
250 400 20
100 4 160 250 13 1
250 400 20
400 650 32
150  6 400 650 32 1
650 1000 50
1000 1600 80 0,1
200  8 650 1000 50 1
1000 1600 80 0,1
1600 2500 130
250 10 1000 1600 80 0,1
1600 2500 130
2500 4000 200
300 12 1600 2500 130 0,1
2500 4000 200
4000 6500 320
400  16 2500 4000 200 0,1
4000 6500 320
6500 10000 500

 

Table 2: Physical properties of most popular gases that may be measured with the CGT turbine gas meters – density at 101,325 kPa and at 20°C

Gas Chemical symbol (formula) Density ρ [kg/m3] Density related
to air		 Gas meter execution
Argon Ar 1,66 1,38 standard IIB
Butane C4H10 2,53 2,10 standard IIB
Carbon dioxide CO2 1,84 1,53 standard IIB
Carbon monoxide CO 1,16 0,97 standard IIB
Ethane C2H6 1,27 1,06 standard IIB
Ethylene C2H4 1,17 0,98 standard IIB
Helium He 0,17 0,14 standard IIB
Methane CH4 0,67 0,55 standard IIB
Natural gas – ~0,75 ~0,63 standard IIB
Nitrogen N2 1,16 0,97 standard IIB
Propane C3H8 1,87 1,56 standard IIB
Acetylene C2H2 1,09 0,91 special IIC
Hydrogene H2 0,084 0,07 special IIC
Air – 1,20 1,00 standard IIB

 

 

PRESSURE AND TEMPERATURE OUTPUTS

The operating pressure (reference pressure) can be taken from the pressure taps, marked pr, located on both sides of the meter body. The meters DN100 and larger can be optionally equipped with two temperature taps for the measurement of the gas temperature.

PULSE SENSORS

The mechanical index unit indicates the actual volume of the measured gas at operating temperature and operating pressure. It can be rotated axially by 350° in order to facilitate the readings and enable easier connection of pulse sensor plugs. The index unit is provided with one low frequency reed contact pulse transmitter (LFK), as a standard. On request the index may be equipped with:

  • LFI – low frequency inductive pulse sensor (NAMUR)
  • HFI – high frequency inductive pulse sensor (NAMUR)

The CGT-02 turbine gas meters may be provided with up to 10 pulse sensors for DN100 – DN400 and up to 8 pulse sensors for DN50 – DN80

  • LFK – low frequency reed contact pulse sensor LFK1, LFK2
  • LFI – low frequency inductive pulse sensor LFI1, LFI2
  • HF – inductive pulse sensor:
    • HF1, HF2 – in the index head
    • HF3, HF4 – over the turbine wheel
    • HF5, HF6 – over the reference wheel
  • AFK – anti-fraud reed contact AFK

The turbine wheel is made of aluminium, as a standard. This allows to provide each turbine gas meters with HF inductive pulse sensors.

 

DIMENSIONS AND WEIGHTS

CGT-02 Gas Meter - DimensionsCGT-02 Gas Meter - Dimensions

 

DN L A B C E, F* Flange Weght
ANSI PN cast iron steel
mm inch mm mm mm mm mm – – kg kg
50 2 150 203 42 58 150 – 16 8,5 11
150 20 9,5 10
226 300 50 – 11,5
– 64 – 14
600 110 – 14
80 3 240 206 60 95 146 – 16 20 25
80 150 20 19,5 24,5
222 300 50 – 27,5
– 64 – 28
600 110 – 32
100 4 300 220 101 124 157 – 16 25 33,5
150 20 26,5 34,4
233 300 50 – 43
– 64 – 40
600 110 – 56
150 6 450 247 125 180 185 – 16 – 62,5
155 150 20 48 62,5
261 300 50 47 80,5
– 64 – 84
600 110 – 106
200 8 600 270 212 240 202 – 16 – 80
150 20 – 86
282 300 50 – 116
– 64 – 128
600 110 – 153
250 10 750 298 270 330 232 – 16 – 142
150 20 – 147
308 300 50 – 190
– 64 – 206
600 110 – 271
300 12 900 323 300 350 258 – 16 – 215
150 20 – 235
345 300 50 – 290
– 64 – 300
600 110 – 360

 

* size E is valid for meters PN16, PN20 and ANSI 150, size F is valid for meters PN50, PN64, PN110, ANSI300 and ANSI600

 

INSTALLATION AND OPERATION RECOMMENDATIONS

  • Meters should be shipped in their original package to the place of installation.
  • Meters have to be handled with care and protected against falls, direct infl uence of rain, snow or high humidity.
  • The measured gas should be clean, dry and free from solid impurities. It is recommended that the upstream pipe installation is to be equipped with a filter (10 micron).
  • Prior to putting into operation in new installations, it is recommended to install a temporary cone sieve.
  • Prior to installation the upstream and downstream pipe fl anges should be aligned properly.
  • Flange gaskets are to be installed so as not to disturb the gas flow.
  • The gas flow should be in accordance with the arrow placed on the meter body.
  • The piping should be executed so as to avoid unnecessary stresses acting on the meter.
  • When used outdoors the meter should be protected against direct weather infl uence.
  • When starting the gas flow through the installation, the valves should be opened slowly to ensure a gradual increase of pressure.

 

ATTENTION! If valves are opened abruptly or pressure increase takes place in a short time it may happen that the measurement cartridge or the turbine wheel get damaged.


ALWAYS REMEMBER TO START UP THE METERS IN A PROPER WAY!

 

The research and development program is being continued by COMMON S.A. Technical specifications and construction may change due to improvements. This publication serves s general information only, and all specifications are subject to confirmation by COMMON S.A.

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