High-Pressure Coriolis Flow Meters

Rheonik is a pioneer in the hydrogen fuel cell revolution. From the very outset, Rheonik has worked with all major hydrogen gas suppliers to produce accurate flow meters which handle the extremely high pressures associated with hydrogen dispensing. Hydrogen is transferred into fuel cell vehicles very quickly, and at pressures up to 700 bar (and higher in the future). A flow meter measuring under these conditions must be both accurate and reliable to be usable for end user point-of-sale billing.

Hydrogen fuel dispensers have been installed alongside gasoline and diesel dispensers in many filling stations around the world. Hydrogen fuel cell powered vehicles can pull up, connect a hose, and fill up their tanks, just like vehicles using traditional petroleum-based fuels.  At the heart of every hydrogen dispenser is a point of sale flow meter, which must be Weights and Measures approved to ensure customers receive the exact amount of hydrogen they pay for. Because hydrogen is sold in mass units (kg), Rheonik Coriolis meters are ideal for the application as they read primarily in mass, are rated for high pressure, and have a large measurement turndown capability.

The vast majority of hydrogen dispensers around the world are fitted with Rheonik flow meters. Dispenser manufacturers everywhere are confident that when a Rheonik meter is installed, it will provide the performance and reliability that they, their customers, and the hydrogen buying public require and demand.

Rheonik Coriolis meters have been specifically tested and certified to the OIML R137 standard for the dispensing of hydrogen.  In the field, the accuracy of Rheonik Coriolis meters in hydrogen dispensers is routinely confirmed using certified weigh scales, allowing them to be put into service for point of sale dispensing.  Rheonik transmitters include a lock switch to prevent internal settings and calibration from being changed.  A tamper-proof seal is applied over this switch by local Weights and Measures officials to protect consumers using the dispenser.

Yes. Rheonik can supply meters with pressure ratings up to 20,000 psi (1,378 bar) up to a 1” line size. High pressure natural gas has become more common in recent times as a fuel for large construction equipment and suitably equipped long distance trucks.  Rheonik meters are used in dispensers designed to fill fuel tanks on these vehicles with HPNG.

Rheonik flow transmitters allow a fixed or normal gas density value to be entered by the user. The value can be entered into the transmitter either through the keypad or via digital communications, and is the density of the flowing gas at standard conditions (i.e. 60°F and 1 atm).  Using this density value and live mass flow, the transmitter can display gas flow in normalized or standard gas volume units such as Nm³/h or SCF/h.

• No moving parts. Turbine meters have, of course, a spinning core that rotates as gas passes through it.  Turbine shaft bearing wear is a common problem and requires the meter to be removed from the pipe periodically for maintenance and repair.  In contrast, Rheonik meters have no moving parts to wear, and so have a very low maintenance overhead.
• Turn down. Turbine meters have a limited turndown (typically 10:1), which limits their rangeability.  Coriolis meters have, as a minimum, a 50:1 turndown where good accuracy can be expected.
• Linear response. Turbine meters have a non-linear response to flow across their operating range.  While the designs of turbines are such that the linearity is minimized, 0.5% non-linearity is quite common.  To correct this, multipoint calibrations must be carried out and a linearization table generated.  Coriolis meters are typically linear across their operating ranges and do not require linearization in a flow computer or similar.