Performance

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: ±0.0035 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)	452 bar 6556 psi	402 bar 5831 psi	339 bar 4917 psi	280 bar 4061 psi
Alloy C22	474 bar 6875 psi	421 bar 6106 psi	358 bar 5192 psi	297 bar 4307 psi
Super Duplex * Low Pressure	630 bar 9137 psi	540 bar 7832 psi	410 bar 5947 psi
Super Duplex * Medium Pressure	1050 bar 15229 psi	900 bar 13053 psi	720 bar 10443 psi
Super Duplex * High Pressure	1481 bar 21480 psi	1379 bar 20001 psi	1236 bar 17927 psi
Sandvik HP160®	1219 bar 17680 psi	1175 bar 17042 psi	795 bar 11531 psi
Tantalum	257 bar 3727 psi	198 bar 2871 psi	161 bar 2335 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: 0.000036 kg/min (0.000079 lbs/min).
• Zero point stability of a premium sensor with high accuracy or focused calibration: 0.000019 kg/min (0.000042 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:

• ±0.00308% of maximum flow per °C
• ±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.
• Additional uncertainty 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/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.