Reference

RHM 30

FLOW SENSOR

The RHM 30 is available with a wide choice of material options to suit benign and aggressive applications. Heavy duty variants meet high pressure and high temperature needs while providing the highest accuracy performance.

Range: 10 kg/min up to 900 kg/min
Pressure: up to 405 bar (5874 psi)
Temperature: -196°C (-321°F) up to +350°C (662°F)
Accuracy: 0.1 % of rate
Materials: SS 316L / SS 316Ti, Alloy C22 – 2.4602, Super Duplex – 1.4410, Tantalum – UNS R05200
Process Connection: 1 ¼" up to 3"

CONFIGURE

CATEGORY Medium Size Sensors, Oil Measurement

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

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).

	50 °C 122 °F	120 °C 248 °F	210 °C 410 °F	350 °C 662 °F
SS 316Ti (standard)	137 bar 1987 psi	123 bar 1784 psi	106 bar 1537 psi	89 bar 1291 psi
SuperDuplex Low Pressure ³	258 bar 3742 psi	242 bar 3510 psi	210 bar 3046 psi	n/a
SuperDuplex Medium Pressure ³	462 bar 6701 psi	405 bar 5874 psi	367 bar 5323 psi	n/a

Uncertainties and flow measurement turn-down

All uncertainty statements refer to reference conditions – 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 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 Qnom of the flow sensor is mainly driven by its zero point stability. At the very low end of the measuring range the uncertainty (u) is dominated by the zero point stability. The zero point stability of a standard sensor is: 0.000036 kg/min (0.000079 lbs/min). Zero stability of a Gold Line sensor is 0.000019 kg/min (0.000042 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

Uncertainties from environmental and process conditions

If sensors are not zeroed at operating conditions, minor additional uncertainties can arise from elevated temperatures and pressures: ±0.00308 % of maximum flow per °C and ±0.0208 % of maximum flow per bar.
Process temperature effect on density: additional uncertainty of ±0.000641 g/cm³ per °C difference from calibration temperature with standard density calibration and of ±0.000073 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 0.00012 g/cc per bar. Compensation is possible by pressure sensor input (analog input or digital write) or manual value entry into the transmitter.

(1) Requires 40 Series transmitter or higher
(2) Requires RHE16 or higher transmitter.
(3) Note minimum operating temperature for SuperDuplex stainless steel is -40°C

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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.