NYLD-LGQ Gas Roots Flowmeter
The NYLD-LGQ gas roots flowmeter has been used as a volumetric meter for more
than 100 years. With the features such as high precision, wide
range, small volume, light weight, convenient installation and
maintenance, reliable and durable service life, it is widely used
in natural gas, coal gas, air and other gas flowmeters.It is an
ideal flowmeter device for urban gas, oilfield chemical, scientific
research and other departments at home and abroad.
NYLD-LGQ Gas Roots Flowmeter Technical Parameters
| Model specification | Nominal diameterDN mm) |
Flow limit (m3/h) |
Starting flow m3/h |
Pressure loss at Qmax |
Nominal pressure MPa |
Accuracy % |
Range |
Material |
| NYLD-LGQ-20A | 25 | 20 | 0.05 | 100 | 1.0 1.6 | 1.0 1.5 | 20:1 | Aluminum allo |
| NYLD-LGQ-40A | 40 | 30 | 0.07 | 100 | 30:1 |
| NYLD-LGQ-40B | 40 | 40 | 0.07 | 140 | 40:1 |
| NYLD-LGQ-50A | 50 | 60 | 0.1 | 100 | 65:1 |
| NYLD-LGQ-50B | 50 | 80 | 0.1 | 140 | 70:1 |
| NYLD-LGQ-80A | 80 | 100 | 0.1 | 110 | 70:1 |
| NYLD-LGQ-80B | 80 | 150 | 0.12 | 150 | 120:1 |
| NYLD-LGQ-80C | 80 | 200 | 0.15 | 180 | 70:1 |
| NYLD-LGQ-100A | 100 | 250 | 0.11 | 180 | 80:1 |
| NYLD-LGQ-100B | 100 | 300 | 0.11 | 130 | 110:1 |
| NYLD-LGQ-100C | 100 | 450 | 0.1 | 200 | 110:1 |
| NYLD-LGQ-150A | 150 | 650 | 0.65 | 350 | 80:1 | Aluminum |
| NYLD-LGQ-150B | 150 | 1000 | 0.76 | 450 | 90:1 |
| NYLD-LGQ-200A | 200 | 1600 | 1.15 | 500 | 53:1 |
NYLD-LGQ Gas Roots Flowmeter Operating Principle
(1).The flowmeter consists of 5 parts (see Figure 1)
(2).Intelligent gas roots flowmeter working principle (see Figure
2)
The intelligent gas roots flowmeter consists of a housing, a
conjugate rotor and an intelligent flow totalizer. Under the action
of the pressure difference between the inlet and outlet of the
circulating gas (P inlet>P>outlet),the pair of conjugate
maintain the correct relative position of the rotor through the
precision-machined adjusting gear.The optimum working gap between
the rotor, the rotor and the housing, and the rotor and the wall
plate achieves a continuous non-contact seal.
For each revolution of the rotor,it outputs four times theeffective
volume of the metering chamber, and the number of revolutions of
the rotor is transmitted to the intelligent flow totalizer through
the magnetic sealing coupling device and the speed reducing
mechanism, to display the cumulative volume of the output gas. (The
figure shows only a quarter cycle).
(3).Intelligent flow totalizer working principle
The intelligent flow totalizer consists of temperature and pressure
detection analog channel, flow sensor channel and microprocessor
unit, and is equipped with an external signal interface to output
various signals. The microprocessor in the intelligent flow
totalizer performs temperature and pressure compensation and
compression factor correction according to the gas equation. The
gas equation is as follows:
Where:
Qn: volume flow rate under standard condition (m3/h);
Qg: volume flow rate under working condition (m3/h);
Pg: meter pressure at the flowmeter pressure detection point (KPa)
Pa: local atmospheric pressure (KPa);
Tg: absolute temperature(273.15 + t) (K) of the medium;
t: measured medium temperature (°C);
Zn: compression factor under standard condition;
Zg: compression factor under working condition;
Tn: absolute temperature (273.15+20) (K) under standard state;
Pa: local atmospheric pressure (KPa);
Pn: standard atmospheric pressure (101.325KPa);
P: P = Pa + Pg.
Note:For natural gas Zn/Zg=Fz2, Fz is called super compression
factor. This product is calculated according to the formula of
SY/T6143-1996 of CNPC standard.
