Measurement method:
The hot-wire (thermal) mass method of measurement is based on the dependence of the degree of cooling of a heated sensitive element, placed in the stream, due to flow rate. The heated sensitive element in gas flowmeters is a platinum resistance thermometer.
The instruments maintains in real time the constant difference of temperatures between the heated sensitive element of the hot-wire flowmeter and the thermal converter which measures gas temperature. The power needed for maintaining the constant temperature difference is proportional to the mass speed of the gas flow which passed through the metering section. The current value of gas flow rate is calculated according to the value of dissipated heat power of the hot-wire flowmeter, composition and thermophysical properties of gas, pressure parameters, as well as dimensions of the sensitive element of the primary transducer and pipeline cross-sectional area
Flowmeter purpose:
The Turbo Flow TFG-Н gas flowmeter is used for gas flow rate measurement in the dynamic range 1:1,500.
Field of application:
Gas metering in the utility and domestic sphere:
- Apartment buildings;
- Private houses;
- Other public utilities requiring flow rate measurement in an extended dynamic range
Specific features of flowmeter:
- Can be used for small pipeline diameters;
- A remote temperature sensor;
- Configuration with explosion-proof housing
Merits:
- High accuracy: relative measurement error not more than 1.5% throughout the range of operating flow rate from 2.5% to 1.5%;
- Wide dynamic range of measured flow rates from 0.05 to 1,200 m3/hour (1:1,500);
- The probe version creates no resistance to the flow;
- The instrument can be installed without additional shutoff valves;
- In case of failure it does not block gas supply to the consumer;
- Overpressure of measured medium up to 32 MPa;
- Universal protocol of exchange with automatic process control systems (MODBUS RTU).;
Configuration options:
By configuration of primary transducer:
- With indicator and without indicator;
- With keyboard (if indicator is available) and without keyboard;
- With remote or integrated sensitive element for temperature measurement.
By configuration of flow measurement cabinet:
- Full set (includes a gas flowmeter and remote cabinet);
- Power supply unit only (gas flowmeter with connected power supply unit).
Technical specifications:
| Characteristic |
Value |
| Measurement range of volumetric gas flow rate under standard conditions, m3/h |
from 0.05 to 1,200 |
| Pipeline diameter, mm |
from 25 to 100 |
Limit of permissible relative error during measurement of volumetric gas flow rate, reduced to standard conditions, %
- using the manufacturer’s measuring section ± 1.0 in the range 0.015 Qmax < Q < Qmax
- without using the manufacturer’s measuring section ± 1.5 in the range 0.015 Qmax < Q < Qmax
|
- ± 2.0 in the range Qmin < Q < 0.015 Qmax
- ± 2.5 in the range Qmin < Q < 0.015 Qmax
|
| Gas temperature measurement range, °С |
From minus 60оС to plus 300оС |
| Limits of permissible absolute error during temperature measurement, °С |
±(0,3+0,005|t|),
where t – measured temperature, °C |
| Limits of absolute error during time measurement, s |
± 1 for 24 h |
| Flow speed range, m/s |
От 0,03 до 350 |
| Upper limit of overpressure measurements, kPa |
up to 600
up to 32 |
| Working range of overpressure measurements, % of ULM |
from 33 to 100 |
| Upper limit of absolute pressure measurements, (ULM), MPa |
up to 32 |
| Working range of absolute pressure measurements, % of ULM |
from 33 to 100 |
| Dynamic range (Qmin/Qmax) |
1:1500 |
| Sensitivity threshold |
0,3 Qmin |
| Limits of permissible relative error during pressure measurement, % |
±0,5 |
Performance specification:
| Characteristic |
Value |
PT* operating conditions*:
– ambient air temperature, °C |
From minus 60 to plus 70 |
| Kind of PT* explosion protection |
Ex ib Gb [ia Ga] IIC T4 Gb
or 1 Ex dib Gb [ia Ga] IIC T4 Gb |
| Kind of FMC** explosion protection |
[Ex ib Gb] IIC |
| Protection degree of PT* as per GOST 14254-96 |
IP65 |
| Protection degree of FMC* as per GOST 14254-96 |
IP54 |
| Average mean time between failures, hours, at least |
60 000 |
* PT – primary transducer;
** FMC – flow measurement cabinet.
