CGR Rotary Gas Meter
The rotary gas meters are positive displacement meters, designed to measure quantity of gas, for custody transfer or technical measurement applications. The devices are mainly applied for gas fl ow ranges from 0.2 up to 650 m³/h, and the pressure range up to 20 bar. Special design rotary gas meters may also be used in higher pressure installations.
The CGR Rotary Gas Meters are applied in measurement systems where high accuracy is required:
- Transportation of natural gas
- Primary and secondary measurements
- Control metering of natural gas and non aggressive technical gases in industry
- Flow measurement for technical purposes
Design and Function
The gas flow through the rotary gas meter measurement chamber makes the two “8”-shaped rotors to
turn. The volume of gas closed between the measuring chamber walls and rotors is transported four times in one full cycle from the meter inlet to the outlet.
The timing gears set the rotors at the angle of 90° one to the other. The gear train, and the incorporated
gas tight and hermetic magnetic coupling, transfers the rotor rotation to the index unit, which is separated in
that way from the pressure tight housing. The actual volume of gas is indicated on the mechanical counter.
The measurement cartridge, as a separate unit, is fixed in the pressure resistant housing by means of elastomere
gaskets. Thanks to this, the possible stresses, e.g. arising from improperly aligned piping, have no influence on
measurement results of the CGR Rotary Gas Meter.
Moreover, the measuring cartridge elements are made of materials with carefully selected values of thermal
expansion coefficients.
This minimizes temperature stresses that could cause the rotor seizures.
All above factors, together with the highest precision machining of parts allow to reduce small but necessary
clearances between the moving rotors and the measurement chamber walls, what reduces gas leakages to minimum and results in very high accuracy and wide measuring ranges of our CGR Rotary Gas Meters.
The CGR Rotary Gas Meter consists of the following main assemblies:
- Pressure resistant housing
- Measuring assembly
- Magnetic coupling
- Index head
All parts subject to servicing or maintenance, like mechanical counter, LF (HF) sockets, oil filler and drain
plugs, oil level sight-glass, are located on the front side of the meter. Thanks to this, it is not necessary
to access the back side of the CGR meter and then it could be located very close to a wall or other construction
element that reduces the installation depth.
