The OMEGA VI rotary gas meter of vemm tec Messtechnik GmbH is ...

OMEGA VI Rotary Gas MeterDocumentation and Technical SpecificationsGas - Measurement1

Advantages• Compact one side closed construction, therefore lightweight, high torsion rigidity and little danger forinterlocking of rotors and housing• Light weights design by using aluminium or ductile ironhousing or components• Square rotor design for short meter body, easymounting and large cyclic volume (reduced rotorspeed and low noise)• Low speed magnetic coupling (low wear)• Up to 20 % over capacity possible• All four mounting directions are possible withouta second counter• Flow range up to 1 : 200• Optimized inlet and outlet design to reduce pressure loss• Dirt groove to reduce dust and particle sensitivityIntegrated thermo-wells for temperature or combined pressure/temperaturemeasurement with a volume converterare optionally available.OperationThe OMEGA VI rotary gas meter of vemm tec MesstechnikGmbH is a positive displacement meter for volume and flowrate measurement.It is suited for measuring clean, dry, non-corrosive gases likenatural gas, propane, butane, air, nitrogen, and others. Themeter is used for highly accurate gas measurement where alarge rangeability is required.The meter measures the quantity of a flowing gas at actualgas pressure and actual gas temperature, i. e. at flowingconditions.The metering principle of OMEGA VI is displacement of themetering chamber content by two special shaped rotors.The rotation of the rotors is transferred to a mechanicalcounter and accumulated as volume at measurement conditions.In addition, electronic pulses are generated for registrationand/or for volume conversion to base conditionswith an electronic conversion device.OMEGA VI is designed to deal with over-ranging of 20 % ofQmax, this over-ranging must occur slowly and withoutpulsations.DesignThe rotary gas meter OMEGA VI has two identical, lob shapedrotors that roll off on each other without ever touching. Avery small differential pressure of 0.02 mbar is sufficient tostart the rotors and the meter. The performance of the meteris constant over years, because there is no wear on themoving parts in the measuring chamber. The bearings andgears are permanently lubricated by an oil mist. The bodyhousing is of aluminium (AlSi7Mg0.3) or high strength ductileiron (EN-GJS-400-18-LT; GGG 40). This body material allowshigh pressures and provides noise dampening effects.The meters are suited for:• Gas temperature range -20 to +60 °C• Ambient temperature -20 to +70 °C• Storage temperature -30 to +70 °C• Max. relative humidity 95% non condensingPressure range up to 16 bar (PN 16) or up to 20 bar(ANSI 150).Index Head with Pulse OutputsA special design of both, measurement chamber and thelubrication system, enables you to install the meter in any ofthe four possible mounting positions. In any case, the 355°turnable index head is located at the front of the meter andyou do not need a second counter. The gas flow directionthrough the meter is always the same.The OMEGA VI is equipped with an IP65 index head withmany outstanding features:• Counter is low speed, low friction driven bygas tight magnetic coupling• Eight-digit counter, non-resettable• Sensor: 1 low frequency Reed switch• Index head is 355° turnable for easy access and suitablefor tropical applicationAccuracyThe meter stops counting as soon as the gas flow stops.The high accuracy of OMEGA VI is applicable over a widemeasurement range:± 1 % for 0.05 Qmax to Qmax± 2 % for Qmin to 0.05 Qmax± 0.1 % repeatability or betterAlternative specifications on request.ApprovalsThe OMEGA VI rotary gas meter complies with all national andinternational requirements for gas meters, particularly EN 12480and other rigid regulations for custody transfer applications.The following metrological approvals apply:• CE-MID approval (pending)• Other country approvals (please inquire)Initial Verification and CalibrationGas flow meters for custody transfer purposes need to beverified according to CE-MID. vemm tec´s “Accredited TestCenter – GN 5” can perform such a verification. A calibrationcertificate will be issued.If the meter is not used for custody transfer purposes, a factorycalibration is performed. The “Certificate of Conformity”proves that the meter has been tested and complieswith the stated error limits.On request, we can also take care of a high-pressure calibration,performed at a certified installation.2

Material and Safety TestsAll OMEGA VI rotary gas meters are pressure tested andverified in accordance with the flange rating and with theappropriate standards and customer requirements.• Hydro test of the meter housingat 1.5 maximum operating pressure• Air seal test with the completely assembled meterat 1.1 maximum operating pressure• Material : EN 10204 3.1• CE-PED compliance: Directive 97/23/EC• CE-MID compliance: Directive 2004/22/EC pendingA certification package can be ordered as an option. Othertests are available on request.DocumentationThe OMEGA VI comes with an installation, operation andmaintenance manual. An installation card is attached toeach meter. We recommend that this card stays with themeter. Calibration certificates and material certificates canbe provided as an option.Depending on the order and the meter chosen, the optionallyordered certification package contains:• 3.1 certificate with declaration of conformity• Material certificates for pressure containing parts• Pressure test certificate• Calibration certificates with data and curve (as ordered)• Applicable CE documentation (PED/MID)InstallationThe gas flow must be free from liquids, dust and particles.The use of a strainer or sieve is mandatory (filter mesh 430micron or smaller). The meter must not be installed in thelowest point in a gas line, because condensate and dirt tendto collect here.The meter can be used horizontally or vertically, allowing allfour mounting positions, because of the turnable head andthe symmetrical design.Straight upstream or downstream pipe sections are notrequired for the OMEGA VI. The meter can be installed inthe piping without additional support. It must be mountedwithout externally induced stress. Sudden or extreme pressureand flow variations as well as vibrations and pulsatingflow must be avoided.The meter is preferably installed indoors but is suitable foroutdoor installation. In that case it is recommended to protectthe meter from direct sunlight and rain.Additional InstrumentationThe indicated volume will often be converted to volume atbase conditions. Electronic volume converters usually measurepressure and temperature or only temperature.• PressureTwo pressure taps enable the measurement of the staticpressure in the meter housing.Especially for custody transfer applications, the pressure forvolume conversion shall be measured at the upstream pressurepoint marked with Pr (also designated Pm).The other pressure tap is located downstream at the meterbody, marked with P.• TemperatureThe temperature measurement should preferably be locatedwithin 2 D upstream of the meter. No pressure reducingparts should be located between the temperature sensorand the meter.vemm tec offers a new PT-thermo-well for installation inthe Pr point of OMEGA VI rotary gas meters. It allows installationof both, temperature sensor and pressure transmitterat the meter inlet.Alternatively standard thermo-wells are available that canbe mounted in the upstream piping.Volume Converters and Flow Computersvemm tec can provide you with flow conversion devices,ranging from a converter with only basic features to asophisticated flow computer.We offer such devices on your request. Please inquire formore details.3

Table:OMEGA VIrotary gas meterNominal diameter[mm] (inch)DN 50 (2“) DN 80 (3“) DN 100 (4“)Body material Aluminium Ductile iron Ductile ironSize rating G 40 G 65 max. G 100 G 160 max. G 160 G 250 max.Flow Turn Down Ratio 1:80 1:100 1:150 1:100 1:100 1:200 1:100 1:100 1:200Qmax [m 3 /h] 65 100 120 160 250 280 250 400 480Qmin [m 3 /h] 0.8 1.0 0.8 1.6 2.5 1.4 2.5 4.0 2.4Qstart [m 3 /h] 0.16 0.32 0.51R1 (Reed):k-factor 10 Imp/m 3 1 Imp/m 3 1 Imp/m 3max. frequency 0.3 Hz 0.1 Hz 0.13 HzPressure taps M 12 x 1.5 or M 16 x 1.5Pressure class PN16 (16 bar abs.)(pmax) ANSI 150 (20 bar abs.)Pressure loss < 1.3 < 2.0 < 3.0 < 2.0 < 3.3 < 6.0 < 1.6 < 2.0 < 3.0[mbar]with natural gas of 1.0 bar abs at QmaxL [mm] total length 171 171 241A [mm] width 281 416 495B [mm] 196 248 290C [mm] 85 168 205D [mm] height 206 212 212Weight [kg] 12 20 33Lubricant [ml] horizontal 30 24 24Lubricant [ml] vertical 70 24 24Gas - Measurementvemm tec Messtechnik GmbHGartenstrasse 2014482 Potsdam-BabelsbergGermanyTel. +49 (0) 3 31 / 70 96 274Fax +49 (0) 3 31 / 70 96 270E mail: info@vemmtec.comInternet: http://www.vemmtec.com300–002–004 Changes in course of technical development are reserved. August 2010