2 Features:(Functions and applications)
Features: FLWQ Turbine Meter is a velocity-type flow meter to survey gas flow precisely. It has a lot of advantages, simple structure, higher accuracy, good repetitiveness, wide survey range, easy installation and intuitive readings.
a) Higher accuracy, good repetitiveness, loss pressure exposed and good anti-vibration
b) Usage the self lubricating bearing, small friction drag, well seal ability and prolonged life.
c) Regarded microprocessor, flow sensor, temperature and pressure sensor as one part. To survey the flow, temperature and pressure of gas, compensate flow automatically, revise compressibility factor.
d) Owned pulse signal, output analog signals and RS485 of communication interface
e) Employed SMT installation technology, small volume, compact conformation, strong capacity of resisting disturbance, highly reliable, low power consumption. Provided electricity by inner battery or external power supply.
f) Usage the liquid crystal display to be easy intuitive readings. Conventional type shows the integrated flux and instantaneous delivery. Intelligent type not only shows the integrated flux and instantaneous delivery, but also the temperature and pressure of medium.
g) Functional storage data to power-off protection.
h) Used with IC card payment system to settle up a bill.

2 The usage of environment conditions:
Environmental temperature: -30℃～+55℃
Relative humidity: 5%～95%
Atmospheric pressure: 86kPa～106kPa
Working conditions:
Medium temperature: -20℃～+70℃
Nominal pressure: 1.6MPa
Power source: internal power supply: 3.6V Lithium battery, average current: conventional type＜80μA, Intelligent type＜200μA;
external power supply: three-wire system of 24V current power supply ＜100mA, three-wire system of 24V power supply 4～20mA

2 Working Principle:
Through leading fluid the gas goes into the meter to integrate and accelerate it. The impulse of fluid make the blade own rotating torque. After overcoming the friction torque and fluid drag torque, the blades begin to rotate. The rotate speed of blade is steadily when you keep a balance among rotating torque, friction torque and fluid drag torque. The rotate speed is proportional to the fluid speed under a certain condition, so the rotate pal stance of turbine is proportional to the volume flow of fluid. According to faraday’s law, the location of detector loop will change by the period of rotation of turbine, and the loop production of pulse signal is proportional to the volume flow of fluid of it. Therefore, the frequency of pulse single is proportion to the volume flow of fluid, that is, f=K×Q/3600.  Through magnification, filter, and integration this signal delivers to the converter to be connected with temperature and pressure signal to deal with and show on the screen of LCD. The K not only stands for proportionality constant but the meter constant of flow meter. And the meter constant K is not only in conformity with the accuracy of turbine meters, but also the operation of turbine meters’ converter.

2 Technical performance:
Operative norm:
a) GB/T18940-2003 of national standard; survey the gas flow in the closed conduct; turbine meters
b) Q/FM03-2004 of enterprise standard; FLWQ turbine meters
Accuracy class：The accuracy class of meters in the prescribed flow limit and working conditions.[ Graph]

2 Technical performance:
Enclosure protection grade: IP65
Explosion-proof sign: Flame-proof type: Exd‖BT4; Intrinsic safety: Exia‖CT4～T6
Pressure loss: The pressure loss is related to drive, inside pipe friction, speed of fluid and direction.
Formula:
△P Qmax: medium: dry air (20℃, 101.325kPa, ρ=1.205kg/m3), the maximum flow pressure loss under standard conditions (kPa);
Ρ0: the medium density(kg/m3) in standard conditions(20℃, 101.325kPa)
Pa: local atmosphere pressure (kPa); P0: standard atmospheric pressure (101.325kPa)
Pg: surface pressing of flow meter (kPa)
T0: absolute temperature under standard conditions (293.15K);
Tg: absolute temperature under medium working conditions (273.15+t)K;
Q: working condition flow (m3/h);
Qmax: the maximum working condition flow of meter (kg/m3)[Gas list]

2 Electrical performance index:
Frequency signal: range: <4000Hz; low level<0.7V, high level VD-1V (VD is the power supply voltage)
Analog output: a set of two-wire system 4～20mA , two sets of three-wire system 4～20mA
Communication interface: RS485

2 Installation:
According to the rules, some safety requirements to design, install, supply power or operate the flow meter need to be followed by users.
a) The intensified external magnetic filed disturbance and strong mechanical vibration should not be existed around flow meter.
b) Before installation, the flow meter needs to be pipeline purging to eliminate impurity. Welding in the flange connection is strictly prohibited to avoid burning inside parts.
c) Horizontal installation is needed. The direction of fluid is accord with mark on the enclosure. The enclosure can never act as weighted fulcrum but the pipe. Meanwhile, eliminate the effects of heat expansion act.
d) Being given it coverings is to protect one from weathering if we install it outside. Leave enough space to check and repair.
e) Suggesting install the flow meter in the straight tube as follows:
f) Installing a bypass pipeline is to ensure the normal deliver. To close the bypass pipeline is a must under the normal condition.
g) Installing a regular filter on the upstream flow meter is necessary and consider expansion bend, bellows. To make the stress deformation smaller of meters are according to dimension and pipe lying reasonably.
h) The flow meter should install with pipe coaxial to avoid the gasket seal and butter entering the lumen.
i) Using rope to install the meter in jugular flange. To hoist meter by rope is not allowed.
j) In strict accordance with “electrical performance index” to switch on. To switch on 220VA or 380VA is prohibited under signal output condition.
k) Noticing the highest loading pressure of converter to avoid damaging pressure sensor.
i) The flow meter has to meet the ground reliably when installed in the explosion place. However, it can not use the same grounding line with high voltage system.
It is not allowed to catch the electric welding system. Users should not change the type, standard, attended mode and interface in any conditions. Operating follow the GB3836.1～2direction for use strictly. After cutting the external electric supply, you can open the preoperculum of converter.
m) When operating flow meter, we should open the valve slowly to increase flow rate gradually to avoid the intensified momentary airflow damaging the turbine.