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Ultrasonic gas flowmeter ElMetro-DRU
Ultrasonic gas flowmeter ElMetro-DRU is an advance DSP-technology (Digital Signal Processor) based instrument that is designed to measure volume flow and volume of pure gas and gas mixtures under operating conditions. It could be applied as independent measuring instrument as well as a part of different metering units for natural, oil-dissolved, waste, flared and other types of gases (air, nitrogen, argon).
Measuring complex ElMetro-SGU is a gas measuring complex based on ultrasonic gas flowmeter ElMetro-DRU which is intended for measuring volume flow/volume under operating conditions, archiving measurement data and calculating temperature, pressure and volume flow/volume reduced to standard conditions.
Working principle of measuring complex ElMetro-SGU:
Working principle of measuring complex ElMetro-SGU consists in measuring gas parameters (flow rate, temperature, excess and absolute pressure) under operating conditions with the usage of relevant transducers and further calculation of gas volume and flow rate reduced to standard conditions in accordance to GOST R 8.740-2011 and GOST R 8.741-2011.
Standard components of measuring complex ElMetro-SGU:
- microprocessor-based flow evaluation unit FAU.M (1);
- universal controller MICONT-186 (2);
- ultrasonic flowmeter ElMetro-DGU.1 (-DGU.2) (3);
- temperature sensor with unified current output signal 4-20 mA TSMU and TSPU (basic percentage error: ±0.25%, ±0.5%) (4);
- TSM type resistance temperature detector with nominal static characteristic 100 M in accordance to GOST 6651-2009 (5);
- absolute and excess pressure gauge with current output signal 4-20 mA (basic percentage error is not more than ±0.1%, ±0.15%, ±0.2%, ±0.25%). Gauge type corresponds to GOST 22520-85.
Gas flow rate and volume are measured by ultrasonic gas flowmeter ElMetro-DRU which provides linear conversion of gas volume flow into pulse signal with normalized value or current signal 4-20 mA under operating conditions. Temperature is measured by means of temperature sensors with current output signal 4-20 mA with main reduced error limit not more than ±0.5% or by TSM type resistance temperature detector with nominal static characteristic 100 M according to GOST 6651-2009.
Pressure is measured by means of absolute and excess pressure gauges with current output signal 4-20 mA main reduced error limit not ±0.25%.
Signals on gas parameters are transmitted from metering transducers to inputs of microprocessor-based flow evaluation unit FAU.M or universal controller MICONT-186 that calculate gas flow and volume reduced to standard conditions in accordance to PR 50.2.019-2006 (rules) according to formula 1:
where Pab – gas absolute pressure measured by pressure gauge, MPa;
Pexc – gas excess pressure measured by pressure gauge, MPa;
Pat – atmosphere pressure, MPa;
Voper – gas volume measured by flow sensor under operating conditions, m3;
K – gas-deviation factor;
T – temperature of measured gas defined by the formula no. 2:
T = 273.15 + t,
where t – gas temperature measured by temperature sensor, ºС.
Ultrasonic gas flowmeters ElMetro-DRU which are included in gas measuring complex ElMetro-SGU could be supplied separately as transducers for measuring volume and gas volume flow under operating conditions in any kind of systems, measuring complexes and other equipment.
Evaluation unit FAU.M or universal controller MICONT executes following functions:
- reception and processing of signal transmitted from flowmeters, pressure gauges and temperature sensors;
- calculation of gas volume reduced to standard conditions according to GOST 2939-63;
- measuring operation time with power on and real-time clock display;
- accumulation and logging of data about gas volume, operation time and archiving (including hourly values of following gas parameters: flow rate, pressure and temperature), under operating conditions or reduced to standard conditions;
- data transmission to the upper level via standard RS-232 or RS-485 interface; transmission of data about gas volume in a shape of a pulse signal;
- output of current gas flow parameters, current information on hourly mean values and end parameters in the screen of the display;
- record of the saved information to a memory card by means of a built-in reader at the operator’s request;
- automatic data (archives) backup at a power failure;
- protection against unauthorized alteration of setup parameter.
Working principle of ultrasonic flowmeter ElMetro-DRU:
Flow rate measurement by an ultrasonic flowmeter is based on measuring difference of ultrasonic pulses transmission, view Pic. 1.
Two (for a double-path flowmeter) sensitive elements (piezoelectric sensors P1 and P2) are placed at opposite sides of the measuring tube at a certain angle (α) to the flow direction. Ultrasonic sensors work by turns as a receiver and transmitter. Ultrasonic pulses are emanated at α angle to the gas flow direction. Pulse transmission time in direct (t1) and reverse (t2) flows are:
t1 = L / (C + L·cos(α)),
t2 = L / (C-L·cos(α)),
where L – acoustic path, m;
V – flow speed of measured medium, m/s;
С – the speed of sound, m/s.
Proceeding from the above flow speed of measured medium is:
Volume flow is calculated according to the formula:
Qv=S·V,
where S – cross-sectional area of the flowmeter measuring tube, m2.
From the formula for calculating measured medium flow speed could be found that changes in the speed of sound as a result of pressure or temperature drops do not influence on the measured gas flow speed.
Structure of ultrasonic flowmeter ElMetro-DRU:
Flowmeter consists of a measuring tube (5) with piezoelectric sensors (4) and electronic transmitter (3) which includes housing with a mounted display (2) and cable inputs (1) (at a customer request flowmeter could be supplied with two or four cable inputs), view Pic. 2.
Measuring tube is produced of stainless steel or galvanized steel. Electronic transmitter forms a signal which is transmitted to piezoelectric sensors and initiates excitation of acoustic path signals, as well as provides their consequent receipt. Received signals are amplified and converted into a digital code by a high-speed analog-to-digital converter (ADC), afterward they are processed by a specialized digital signal processor (high-speed DSP-technology). Adaptive filtering and correlation analysis enable to receive measurement data even in case of strong electromagnetic interferences, contamination of the measuring tube or drop fraction in the flow.
Electronic transmitter calculates instantaneous volume flow/volume under operating conditions and converts measured parameters into following output signals:
- pulse/frequency/status (passive, 30 V, 50 mA) - 1 channel;
- frequency/status (passive, 30 V, 50 mA) - 1 channel;
- status (passive, 30 V, 50 mA) - 1 channel;
- analog current 4-20 mA (passive) - 1 channel;
- digital RS-485, Modbus RTU protocol. HART* (IV quarter of 2017).
Local operator interface of the electronic transmitter includes graphic display (LCS or graphic OLED) and capacitive keyboard (configuration without taking off the cover). That enables to carry out flowmeter’s configuration setup even in explosion hazardous areas. To prevent flowmeter from unauthorized alteration of setup parameters a pile of keyboard functions is blocked by turning microswitches under the cover of electronic transmitter.
Technical characteristics of measuring complex ElMetro-SGU:
Gas measuring complex ElMetro-SGU based on ultrasonic gas flowmeter ElMetro-DRU is intended for measuring volume flow/volume under operating conditions, archiving measurement data and calculating temperature and pressure of measured medium, for example, oil-dissolve, natural, flared and other types of pure and contaminated gases (air, nitrogen, argon and etc).
Structural types:
Flowmeter ElMetro-DRU has a flanged connection type (view Pic. 2). In the end of 2017 a new stub-in structural type will be released for pipelines with oval or square cross-sections between 100 to 1000 mm.
Pressure and temperature gauges have thread connection (or customized).
Microprocessor-based flow evaluation unit FAU.M and universal controller MICONT-186 could be mounted in the panel, on a strut support (стойке) or at the wall.
Gas measuring complex ElMetro-SGU is resistant to hydraulic impacts, contaminations and drop fraction.
Gas measuring complex ElMetro-SGU is capable to measure direct and reverse flows with minimum pressure losses.
Measured medium parameters:
- excess pressure, MPa: 1.6; 2.5; 4.0; 10.0*; 16.0*;
- density under standard conditions, kg/m3: not less than 0.6;
- temperature, ºС: from -40 to +50 (from -70 to +120)*;
- content of mechanical particles, mg/m3: not more than 50;
- gas flow state: steady, smoothly changing.
Dimensions range and modifications of gas measuring complex ElMetro-SGU are determined by dimensions range and modifications of flowmeters ElMetro-DRU. Dimensions range and modifications of ElMetro-SGU in its standard configuration as well as ranges of operating gas consumption (under working conditions) are listed in Table 1 below.
Dimensions range and modifications of gas measuring complex ElMetro-SGU Dimensions range and modifications of ultrasonic flowmeter ElMetro-SGU Nominal diameter (Dn), mm Excess pressure of measured in the range, MPa Range of operating flow speeds (rates), m/s (m3/h) Table 1. Dimensions range and modifications of gas measuring complex ElMetro-SGU in standard configuration and ranges of operating gas consumption (under working conditions) Vmin (Qmin) Vmax (Qmax) SGU.1-50 DRU.1-50 50 from 0 to 2.5 MPa
from 0 to 4.0 MPa0.35 (2) 34.9 (200) SGU.1-80 DRU.1-80 80 0.31 (5) 34.6 (550) SGU.1-100 DRU.1-100 100 0.31 (7) 34.9 (800) SGU.1-150 DRU.1-150 150 0.31 (17) 34.3 (1900) SGU.1-200 DRU.1-200 200 0.32 (35) 33.1 (3600) SGU.1-300 DRU.1-300 300 0.31 (80) 29.9 (7600) SGU.2-100 DRU.2-100 100 0.31 (7) 34.9 (800) SGU.2-150 DRU.2-150 150 0.31 (17) 34.3 (1900) SGU.2-200 DRU.2-200 200 0.32 (35) 33.1 (3600) SGU.2-300 DRU.2-300 300 0.31 (80) 29.9 (7600) Number of devices connected to flow evaluation unit FAU.M or controller MICONT-186:
- ultrasonic flowmeters ElMetro-DRU, 1-4 pcs;
- temperature sensors, 1-4 pcs;
- pressure gauges, 1-4 pcs.
Measurement accuracy:
Main relative error of measuring volume flow and gas volume under operating conditions shall not exceed:
- for measuring complex ElMetro-SGU.1 (configuration with ElMetro-DRU.1):
- in the range between Qmin and 0.03·Qmax: ±2.0%;
- in the range between 0.03·Qmax and Qmax: ±1.5%;
- for measuring complex ElMetro-SGU.2 (configuration with ElMetro-DRU.2):
- in the range between Qmin and 0.03·Qmax: ±1.5%;
- in the range between 0.03·Qmax and Qmax: ±1.0%.
Main relative errors of measuring volume flow reduced to standard conditions (δSGU) are listed in Table 2 below.
Ultrasonic flowmeter ElMetro-DRU Temperature sensor Pressure gauge Gas measuring complex ElMetro-SGU (δSGU) Table 2. Main relative errors of measuring volume flow reduced to standard conditions (δSGU) Error, % Error, % Range, ºC Error, % Range, ºC Upper limit, % 1.0 0.5 from -50 to +50 0.1 0.2 1.5 0.5 0.2 0.3 0.5 0.25 0.4 0.5 0.25 0.3 2.0 0.5 0.25 0.2 2.5 1.5 0.5 from -50 to +50 0.1 0.2 2.0 0.5 0.2 0.3 0.5 0.25 0.4 0.5 0.25 0.3 2.5 In case limits of permissible error of measuring complex ElMetro-SGU components differs from that listed in Table 2, then δSGU should be calculated according to the formula:
where δB - limit of main relative error of flow evaluation unit FAU.M or controller MICONT-186 for measuring gas volume reduced to standard conditions, %;
δd.r. - limit of main relative error of flowmeter ElMetro-DRU, %;
δt.s. , δp.g. – limits of main reduced error of temperature sensors and pressure gauges, %;
δK – maximum error of calculating compressibility coefficient (0.3%);
Аt , Ар – measurement ranges of a temperature sensor and a pressure gauge correspondently, °С и MPa;
ti – gas working temperature, °С;
Рi – gas working excess pressure, MPa.
Absolute error for measuring gas temperature does not exceed ±0.8 ºС.
Main relative error for measuring excess pressure (under main reduced error of the sensor not more than ±0.25%) does not exceed ±1.5% under 20-100% of upper measurement range of pressure gauge.
Main relative error for measuring operating time does not exceed 0.1 %.
Ex-proof provision:
Temperature sensors and pressure gauges are equipped with Ex-proof of 1st level in accordance to GOST 12.2.020. Ex-proof is represented by Ex-proof enclosure - d. Category of explosive mixture - IIB, T5 group.
Ex-proved type of flowmeter ElMetro-DRU is available with Ex-proof enclosure and 1ExdIICT6X marking.
Gas measuring complex ElMetro-SGU is available with E-proof which corresponds to GOST R 51330.0, GOST R 51330.14 and ensures safe operation in explosion hazardous areas of facilities class V-1a, V-1b, V-1d according to clause 7.3 of PUE (Electrical Installation Code).
Unit FAU.M and controller MICONT are produced as general purpose industrial types and must be operated in explosion safe areas.
Functionality:
Gas measuring complex ElMetro-SGU corresponds to all requirements of Gas Metering Rules and GOST 8.733-2011 and executes following functions:
- measurement of gas flow rate and volume under operating conditions;
- measurement of gas temperature (in ºC);
- measurement of gas excess and absolute pressure (in kPa, MPa);
- measurement of operating time with power on and display of real-time clock;
- calculation of gas volume and flow rate reduced in accordance to GOST R 8.740-2011, GOST R 8.741-2011 to standard conditions of GOST 2939-63;
- calculation of hourly average values of gas flow parameters (pressure, temperature, flow rate in operating and reduced to normal conditions) at a controlled pipeline;
- accumulation of data about gas volume under conditions reduced to normal running total at a controlled pipeline, in cubic meters;
- visualization of all measured parameters and calculated parameters in a built-in display;
- data transmission to the upper level by means of a standard interface RS-232 or RS-485;
- accumulation and storage of specified parameters during not less than 2 months;
- record of saved information to a USB flash card (at controller MICONT-186) or MMS type memory card (unit FAU.M) at the customer request;
- self-test and blocks and units testing included in measuring complex ElMetro-SGU;
- saving data about hourly average and total values of parameters at power failure.
Ambient temperature range:
Flowmeter ElMetro-DRU, pressure gauge and temperature sensor could be installed in premises or outside (under a shelter) and operated under ambient temperatures between -40 and +50 ºС (for configurations with LCD: from -20 to +50 ºС) with relative humidity up to 95% under temperature +30 ºС.
Evaluation unit FAU.M and controller MICONT-186 are installed in closed heated spaces and operated under ambient temperatures between +5 and +50 ºС with relative humidity up to 90% under temperature +25 ºС.
Ingress Protection Rating:
Protection from environment impacts (dust and water) of gas measuring complex ElMetro-SGU corresponds to requirements of GOST 14254:
- ultrasonic flowmeter ElMetro-DRU: IP65;
- pressure gauge: IP65;
- temperature sensor: IP65;
- flow evaluation unit FAU.M: IP40;
- universal controller MICONT-186: IP40.
Power supply:
Flowmeter ElMetro-DRU has two option of power supply voltage for the electrical transmitter: from 80 to 264 V AC with frequency 50±1 Hz and from 20 to 140 V DC. Built-in power supply unit provides automatic switching between power supply modes. Power consumption of the flowmeter does not exceed 12 V·A.
Flow evaluation unit / controller are powered from AC network with 50±1 Hz frequency and 220±22 V voltage. Flow evaluation unit / controller create 24 V output voltage to power the flowmeter, temperature sensor and pressure gauge.
Total power consumption of measuring complex ElMetro-SGU is not more than 25 V·A.
Maximum length of communication line between evaluation unit FAU.M (or controller MICONT), temperature sensors, pressure gauges and flowmeter is 500 meters.
Technical requirements
Recommended length of a straight-section before and after flowmeter ElMetro-DRU:
- 20·Dn before flowmeter (without flow straightener);
- 10·Dn before flowmeter (with flow straightener);
- 3·Dn after flowmeter.
Weight:
Total gross weight of a packed measuring complex ElMetro-SGU.1 (with flowmeter ElMetro-DRU.1) is not more than 230 kg.
Overall dimensions and weight of temperature sensors, pressure gauges, evaluation units FAU.M and controllers MICONT-186 could be found in maintenance documentation of the specified products.
Overall dimensions and weight of ultrasonic flowmeter ElMetro-DRU are listed in its manual instruction.
Verification interval: 3 years. Verification in simulation mode will be available in IV quarter of 2017.
Mean time between failures is not less than:
- for ultrasonic flowmeter ElMetro-DRU: 75000 h;
- for flow evaluation unit FAU.M: 75000 h;
- for universal controller MICONT-186: 75000 h.
Life-time of measuring complex ElMetro-SGU: not less than 12 years.
Guarantee commitment: 12 months from the date of setting into operation.
Model code structure of ultrasonic flowmeter ElMetro-DRU is listed in Appendix A of manual instruction.
Supply package
Standard supply package of gas measuring complex ElMetro-SGU includes: ultrasonic gas flowmeter ElMetro-DRU (1 pc.), temperature sensor (1 pc.), pressure gauge (1 pc.), flow evaluation unit FAU.M or controller MICONT-186 (1 pc.), manual instruction (1 pc.), calibration procedure description (1 pc.), connection kit (1 set), CD with software and other information (1 pc.), package (1 pc.).
Extended supply package also includes: videographic recorder ElMetro-ViER, input/output module ElMetro-IOM, power supply unit ElMetro-IPТ, USB/RS-485 interface converter and etc.
Application of gas measuring complexes ElMetro-SGU and ultrasonic flowmeters ElMetro-DRU:
Gas measuring complex and ultrasonic flowmeters are applied in industrial and municipal facilities for commercial and technological metering, at gas treatment units, gas tank batteries of gas metering systems, outgoing gases metering systems at fuel burn units, flue gases metering systems at on-site facilities, systems for continuous environmental monitoring of outgoing gases, systems for continuous metering of outgoing gases parameters, flare gas recovery units (FGRU), underground storing systems, complex gas treatment plants (CGTP), transportation and distribution systems, units for gas processing/extraction and etc.
Main industries: oil and chemical, gas extracting, energy, metallurgy, pulp and paper, cement industries, waste recycling, ventilation systems and etc.
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To make enquiry and get a commercial offer on ultrasonic flowmeters ElMetro-DRU or measuring complexes ElMetro-SGU of the Russian manufacturer ElMetro company, please, send us product order code (view codes description in manual instruction) to e-mail: info@elmetro.ru or contact us via tel.: +7 (351) 220-06-01. To discuss technical questions, please, refer to technical support tel.: +7 (351) 220-06-03.