Fuel Gas Flow Meter (LWGQ Series)

A fuel gas flow meter measures volumetric gas flow through a free-spinning rotor mounted in the pipe bore. Fuel gas accelerates through an integrated upstream flow conditioner, the rotor blades intercept the conditioned flow at a fixed angle, and a magnetic pickup downstream of the rotor reads pulses from a co-rotating signal wheel. Pulse frequency is proportional to volumetric flow through the calibrated K-factor. Built-in temperature and pressure compensation outputs corrected mass flow in kg/h or Nm³/h directly on the 4-20 mA loop or HART, with no external multivariable transmitter required for refinery DCS integration.

The fuel-gas build is the refinery and petrochem version of the LWGQ Series. City-gas distribution turbines run at 1.6 to 4 MPa with aluminium body and pulse plus 4-20 mA outputs sized for AMR billing. Refinery fuel-gas headers run at 4 to 10 MPa with sulfur-bearing off-gas, so the fuel-gas build ships with 316L body standard for residual H₂S tolerance, ANSI 600LB flange class for high-pressure service, HART and RS-485 Modbus as primary outputs for DCS-heavy environments, and Ex d II CT6 Gb hazardous-area certification standard for Class I Div 1 refinery zones.

The fuel-gas build covers DN50 to DN300 (2″ to 12″) for refinery and petrochem header service. Pressure classes are 1.6 / 2.5 / 4.0 / 6.3 / 10 MPa metric, with ANSI 150 LB, ANSI 300 LB, and ANSI 600 LB flange ratings selectable at order. ANSI 600 LB is the typical pick for refinery off-gas headers feeding fired heaters and ethylene cracker furnaces where header pressure runs 4 to 10 MPa. Medium temperature is −25 to +80 °C; body material is 316L standard with 304, aluminium alloy, and titanium alloy as alternatives for specific applications.

The 316L stainless body and 316L sensor are the standard build for refinery fuel-gas with residual H₂S up to 4 ppm after amine sweetening. For higher H₂S levels or chloride carry-over from upstream process units, titanium alloy body and sensor are the upgrade. The meter requires clean dry fuel gas at the inlet, so an upstream filter sized for the service is part of every install. Wet gas, condensate carry-over, and 2-phase service exceed the LWGQ operating range; route those to the LUGB vortex Series or to a Coriolis build instead.

HART and RS-485 Modbus RTU are the primary outputs for refinery and petrochem DCS rollouts. HART runs on the same 4-20 mA two-wire pair as the analog loop, so a HART-multiplexer reads the full process variable set (flow, temperature, pressure, totalizer, K-factor, fault codes) without separate wiring. RS-485 Modbus polls up to 32 meters on one serial trunk for plant-wide aggregation. Pulse 3-wire and 4-20 mA remain available for legacy panel-mount counters and SCADA gateways. Maximum cable run is 1500 m for 4-20 mA and 1200 m for RS-485 and HART.

Standard lead time is 5 to 7 business days from order confirmation, factory direct. Each meter ships with an ISO 9001 calibration certificate listing the K-factor, calibrated DN, and tested flow range. Hazardous-area certification is Ex d II CT6 Gb (flameproof, Class I Div 1 equivalent) standard for refinery and petrochem zones, with Ex ia II CT6 Ga (intrinsically safe) optional for classified-area instrument skids. EMC compliance to the EU Electromagnetic Compatibility Directive 2014/30/EU (Annex II) ships standard, with IP65 and IP66 ingress ratings selectable at order.