CNG Mass Flow Meter

A CNG Coriolis mass flow meter measures compressed natural gas directly as mass flow at dispenser pressure (20 to 25 MPa). Two parallel measuring tubes vibrate at their resonant frequency; CNG flow through the tubes generates Coriolis force that twists the tube pair, and pickup coils read the phase shift between inlet and outlet motion. The phase shift is directly proportional to mass flow, with no temperature or pressure correction loop required. The meter ships with 9/16-18 UNF and 13/16-16 UNF threaded connections that match industry-standard CNG dispenser fittings worldwide, and outputs mass flow on 4-20 mA + pulse + RS-485 Modbus or HART for station SCADA and POS integration.

The LWGQ Natural Gas Turbine is the city-gas distribution custody pick at 1.6 to 10 MPa header pressure on DN50 to DN300 mains; the right meter for utility distribution billing. The CNG Coriolis covers the higher-pressure 20 to 25 MPa dispenser service that the turbine pressure class does not reach, and at the small-bore (DN8 / DN15) dispenser flow rate where turbine rangeability becomes limited. The Coriolis also outputs mass directly at dispenser pressure with no T+P correction loop, while the turbine relies on built-in T+P compensation to convert volumetric pulse to corrected mass. For pipeline distribution: use the LWGQ. For refueling dispenser, mother-daughter trade transfer, and compressor outlet: use this Coriolis.

A mother-daughter station setup transports CNG by trailer (or short pipeline) from a mother station with pipeline gas access to a daughter station in a remote location without a pipeline. The transfer point between mother and daughter is the custody boundary for inter-utility billing; the daughter station pays the mother station for the CNG delivered, so the transfer meter must be custody-grade for fiscal reconciliation. The CNG Coriolis with the ±0.1 % rate accuracy build + dual-pulse output (one pulse channel to the billing system + one to a prover station for periodic verification) covers this service. Each meter ships with an ISO 9001 calibration certificate listing the K-factor and zero-stability data for the audit trail.

CNG dispenser custody approval is buyer-arranged with a notified body under the local CNG metrology regime; the meter does not ship with a fiscal billing type-approval certificate ex-factory. In practice this means: in the US, NIST HB 44 dispenser approval is handled by the dispenser OEM / station operator with state weights-and-measures; in the EU, MID Annex MI-002 covers gas meters under category B and is handled by the dispenser package integrator with the notified body; in Brazil, INMETRO carries CNG retail approval; in China, GB/T 22634 covers CNG vehicle refueling. ProFlow provides the ±0.1 % rate hardware build, the ISO 9001 calibration certificate, and the zero-stability data sheet that the local approval pathway needs as input.

The CMASS sensor hardware (DN8 / DN15 bodies with 9/16-18 UNF and 13/16-16 UNF threaded connections) is shared between CNG and hydrogen builds because both applications fit the same form factor; small-bore, high-pressure, threaded process connection, dispenser cabinet integration. The two builds diverge on three points: working pressure (CNG dispenser at 20 to 25 MPa vs hydrogen H35 at 35 MPa and H70 at 70 MPa, so the hydrogen build runs the higher pressure class); accuracy default (CNG ships ±0.1 % / ±0.2 % / ±0.5 % across the dispenser service; hydrogen adds the ±0.15 % mid-grade for HRS custody); and custody-pathway documentation (CNG goes under local CNG metrology regime, hydrogen goes under the international H2 refueling-station dispenser approval pathway).

Standard lead time is 5 to 7 business days from order confirmation, factory direct, with calibration on the order build before shipment. Each meter ships with an ISO 9001 calibration certificate listing the K-factor, calibrated DN, zero-stability data, and tested flow range. Hazardous-area certification is Ex d [ia] IIC T6 Gb (flameproof + intrinsically safe combined) standard for CNG dispenser cabinet and compressor-station classified zones, with IP67 ingress rating standard for outdoor dispenser-housing service. EMC compliance to the EU Electromagnetic Compatibility Directive 2014/30/EU (Annex II) ships standard. CNG custody type-approval (NIST HB 44 / MID / INMETRO / GB/T) is buyer-arranged with the notified body in the destination market.