Rheonik RHM20 Coriolis Flow Sensor

Rheonik RHM20 Coriolis Flow Sensor is a 2″ meter designed for general-purpose flow measurement without the need for maintenance. Robust and accurate, the RHM 20 outperforms other flow technologies at an attractively low cost of ownership.

  • Range: 1 kg/min up to 480 kg/min
  • Pressure: up to 345 bar (5003 psi)
  • Temperature: -196°C (-321°F) up to +350°C (662°F)
  • Accuracy: 0.1 % of the rate
  • Materials: SS 316L / SS 316Ti, Alloy C22 – 2.4602, Tantalum – UNS R05200, Super Duplex – 1.4410
  • Process Connection: ¾” up to 2 ½”
Rheonik RHM20 Coriolis Flow Sensor

General Specifications

Nominal Flow (Qₙₒₘ)* 300 kg/min (661.4 lb/min)
Maximum Flow (Qₘₐₓ)* 300 kg/min (661.4 lb/min)
Typical Minimum Flow (Qₘᵢₙ)* 3 kg/min (6.6 lb/min)
Serial Tube / Single Path Flow rates Qmax, Qnom, and Qmin for “serial” sensors will be 50% of the above-listed parallel/dual path version.
Operating Temperature Fluid temperature range options cover applications from -196°C to 350°C (-320°F to 662°F).
Ambient Temperature -50 °C to +80 °C (-60 °F to +180 °F) (standard), versions available for installation in a vacuum chamber (-260 °C / -430 °F) or oven (up to +210 °C / +410 °F) (optional)
Pressure Ratings Up to 1379 bar / 20000 psi – dependent upon material
Electrical Connection Sensor
w/o Integral Transmitter
M20 x 1.5 standard cable entry for JM, SM terminal box versions

Optional entries available: ½” NPT or M25 x 1.5 (only for SM) or ¾″ NPT (only for SM)

M16 x 1.5 standard cable entry for PM terminal box version

Max. cable length to remote RHE transmitter 100 m/330 ft

Sensor Enclosure Materials Stainless steel 304 (standard), SS 316 (optional)

Coated aluminum terminal box, SS 316 terminal box (optional)

Enclosure Type Protection class IP66, NEMA 4X (standard), IP66/67, NEMA 4X/6 (optional)
Wetted Materials Flow tubes SS 316Ti, Alloy C22, Tantalum or SuperDuplex

Manifolds SS 316L; Seal material (manifold construction): PTFE

Standard flanges SS 316Ti, other connections SS 316L

Additional/customer-specific materials available upon request

Process Connections Nearly any – the Rheonik AnyPipeFit Commitment.  Consult the factory for types/sizes not listed in this data sheet on the Mechanical Construction pages
Pressure Rating Compliance Europe – PED: Sound Engineering Practice (SEP), Module A2, Module B3.1+C2

Canada – CRN: Canadian Registration Number

Certifications and Approvals ATEX / IECEx Approvals for Zone 0, 1 (details see page 17)

North American Approvals Class I, Div. 1, 2, Gr. A, B, C, D, Zone 0, 1

American Bureau of Shipping (ABS) Product Type Approval for use on marine vessels

Testing and Inspection All sensors are hydro-tested, calibrated, and supplied with a traceable calibration certificate. Customized calibration and testing services are available
Project Documentation and QA, Services Rheonik offers a full set of services for large and complex engineering projects.
Typical services offered are, but are not limited to:•Certificates of origin and conformity, mill certificates•Data books including WPAR, WQS, NDT, test & quality plans, functional testing, calibration procedures, customized packing, factory acceptance, etc.•Painting to project specification

•Start up and commissioning services on/offshore

Options Enclosure heating for high-temperature applications

Cleaning for oxygen service, …

For more consult the factory

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Typical applications include:

  • General Flow Control
  • Plant Balance
  • Additive Dosing
  • Mixing and Batching
  • Package and Container Filling


Rheonik RHM20 Coriolis Flow Sensor
  • The typical measuring range is up to 300 kg/min (661.39 lb/min)
  • Pressure ratings up to 586 bar (8499 psi)
  • Temperature ratings from -196 to +350 °C (-320 to +662°F) – extended on request
  • Mass flow uncertainty down to 0.05%
  • Repeatability down to 0.05 %
  • 4 kHz measurement updates and response time of less than 10 ms when used with RHE 40 Series transmitters
  • Accurately measure flow rates down to 3 kg/min
  • The Rheonik AnyPipeFit Commitment provides custom process connection type and size flexibility on any meter to suit your existing plant, saving time and expense on installation costs
  • Compact design with minimal pipeline footprint
  • Approved for use in hazardous areas
  • SS 304 Stainless steel enclosure, SS 316 optional
  • Integral and remote transmitter versions are available

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Mechanical Construction

Sensors are manufactured with two internal measurement tubes arranged side by side. In parallel or dual path sensors (order code Pxx), these tubes are connected in parallel and the flowing fluid is split equally between them. In serial or single-path sensors (order code Sxx), the internal tubes are connected end to end, creating a single path through which all fluid flows. Manifold designs have a removable inlet/outlet manifold block and utilize selectable seals between the manifold and sensor body. In sealless designs, the measurement tubes are continuous between the process connections and do not have seals. Manifold designs offer shorter delivery lead times and may have a lower pressure drop than sealless designs for the same flow rate.

Performance Data

  • Flow Measurement Uncertainty
    Selected Sensors down to ±0.10 % ¹ of rate (Gold Line)
    Standard Sensors down to ±0.15 % ² of rate
  • Flow Measurement Repeatability
    Down to ±0.05 % of rate
  • Temperature Measurement
    Better than ±1 °C
  • Density Calibration (Liquid)
    Selected Sensors down to ±0.0005 kg/liter (Gold Line)
    Standard Sensors down to ±0.001 kg/liter

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Measurement Tube Pressure Ratings

The maximum pressure (Pmax) of a sensor is determined by its lowest-rated part. The lowest rated part can be either the measurement tube (Pmax indicated below), the connection block/manifold
(Pmax indicated in the mechanical construction section) or the process connection (for Pmax see published standards or manufacturer information).

Uncertainties and Flow Measurement Turn-down

All uncertainty statements refer to reference conditions – the mass flow of water, 18 – 24 °C, 1 – 3 bar in a standard temperature, pressure, and material configuration sensor. The sensor can be used to measure gas – uncertainty values for gas equal to the liquid value plus 0.3 %. Reference conditions for gas are mass flow of natural gas, 18 – 24 °C, 35 to 100 bar in a standard temperature, pressure, and material configuration sensor.

The turn-down capability from the Qnom of the flow sensor is driven mainly by its zero-point stability. At the very low end of the measuring range, the uncertainty (u) is dominated by zero-point stability. The zero point stability of a standard sensor is 0.00246 kg/min (0.00542 lbs/min). The zero point stability of a Gold Line sensor is 0.0012 kg/min (0.00264 lbs/min).

For flow Q ≥ zero stability / (calibration uncertainty/100) u = calibration uncertainty
For flow Q < zero stability / (calibration uncertainty/100) u = (zero stability/Q) x 100

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Uncertainties from environmental and process conditions

  • If sensors are not zeroed at operating conditions, minor additional uncertainties can arise from elevated temperatures and pressures:  ± 0.00022 % of maximum flow per °C and  ±0.0005% of maximum flow per bar.
  • Process temperature effect on density: additional uncertainty of ±0.000071 g/cm³ per °C difference from calibration temperature with standard density calibration and of ±0.000009 g/cm³ per °C difference from calibration temperature with enhanced density calibration. This effect can be mitigated by a simple field density adjustment at operating conditions.
  • Process pressure effect on mass flow: The effect of pressure on flow measurement is 0.0001 % of the rate per bar. Compensation is possible by pressure sensor input (analog input or digital write) or manual value entry into the transmitter.
  • Process pressure effect on density: The effect of pressure on density measurement is 0.000075 g/cm³ per bar. Compensation is possible by pressure sensor input (analog input or digital write) or manual value entry into the transmitter.