RHM 04

FLOW SENSOR

The RHM 04 is a fast response solution for batching, dispensing and filling applications. Very high pressure ratings allow deployment in processes where Coriolis meter use has not been possible in the past.

Range: 0.05 kg/min up to 18 kg/min
Pressure: up to 1401 bar (20319 psi)
Temperature: -196°C (-321°F) up to +350°C (662°F)
Accuracy: 0.1 % of rate
Materials: SS 316L / SS 316Ti, Super Duplex – 1.4410, Sandvik HP160, Alloy C22 – 2.4602
Process Connection: ¼" up to 1"

CONFIGURE

CATEGORY Small Size Sensors, H2 Filling Station, Chemical Injection, Fuel Consumption, Refrigerant Filling, Oil Measurement, Painting/Coating Lines, Plastics Production

Performance Data

Flow Measurement Uncertainty
Standard: 0.20 % of rate
Enhanced: 0.15 % of rate
Premium: 0.10 % of rate
Ultimate: 0.05 % of rate – requires RHE 40 Series transmitter
Low Flow Calibration: 0.10 % of rate – requires RHE 40 Series transmitter
Customized Calibration: Consult factory

Low flow calibration focuses on the range from ½ × Qₙₒₘ downwards to lower flow rates than on other calibrations. Often used for low pressure gas or very viscous liquids. Customized calibration uses specific calibration points according to customer requirements.

Flow Measurement Repeatability
Standard Sensors: ±0.1 % of rate
Premium Sensors: ±0.05 % of rate

Temperature Measurement
Better than ±1 °C

Density Calibration (Liquid)
Standard: ±0.001 kg/l uncertainty
Premium: ±0.0005 kg/l uncertainty – requires High Accuracy or Focused Calibration Option

Reference conditions: 18–24 °C Water @ 1–3 bar

Measurement Tube Pressure Ratings

The maximum pressure (pₘₐₓ) of a sensor is determined by its lowest rated part: the measurement tube (see table below), the connection block (see datasheet) or the process connection (see corresponding standards or manufacturer information).

If applicable, the material of a connection block is always SS 316L. For sensors in sealless versions, the material of the process connection is usually the same as the material of the measurement tubes. In special cases, the material may differ.

	50 °C 122 °F	120 °C 248 °F	210 °C 410 °F	350 °C 662 °F
SS 316L (standard)	177 bar 2567 psi	157 bar 2277 psi	132 bar 1914 psi	113 bar 1639 psi
Alloy C22	249 bar 3611 psi	221 bar 3205 psi	188 bar 2727 psi	156 bar 2262 psi
Super Duplex * Low Pressure	712 bar 10326 psi	662 bar 9601 psi	594 bar 8615 psi
Super Duplex * Medium Pressure	1087 bar 15765 psi	1048 bar 15199 psi	709 bar 10283 psi
Super Duplex * High Pressure	1401 bar 20319 psi	1304 bar 18912 psi	1170 bar 16969 psi
Sandvik HP160® Low Pressure	600 bar 8702 psi	540 bar 7832 psi	490 bar 7106 psi
Sandvik HP160® High Pressure	1087 bar 15765 psi	1048 bar 15199 psi	709 bar 10283 psi

* Minimum operating temperature for Super Duplex stainless steel is -40 °C. Maximum pressure may be lower depending on the design type.

Uncertainties and flow measurement turn-down

The turn down capability from 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.

• Zero point stability of a standard sensor with general accuracy calibration: 0.0006 kg/min (0.00132 lbs/min).
• Zero point stability of a premium sensor with high accuracy or focused calibration: 0.0004 kg/min (0.000882 lbs/min).
• uncertainty = calibration uncertainty, if: flow ≥ (zero point stability / (base uncertainty/100))
• uncertainty = (zero point stability/Q)*100, if: flow < (zero point stability / (base uncertainty/100))

Uncertainties from environmental and process conditions

If sensors are not zeroed at operating conditions, minor additional uncertainties can arise from elevated temperatures and pressures:

• ±0.001% of maximum flow per °C
• ±0.00011% of maximum flow per bar

Process temperature effect on density:
• Additional uncertainty of ±0.000061 g/cm³ per °C difference from calibration temperature with standard density calibration.
• Additional uncertainty of ±0.000011 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 0.001% of 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 0.00002 g/cm³ per bar. Compensation is possible by pressure sensor input (analog input or digital write) or manual value entry into the transmitter.

Applying Premium calibration to higher pressure, special materials and/or non-standard temperature models may show higher zero uncertainties (up to 3 times higher than standard sensor).

Couldn’t find what you were looking for?

Other wetted materials may be possible for chemical compatibility, lower pressure drop, abrasion allowance or other application specific requirements. Rheonik can provide nearly any material for the wetted parts.