Yokogawa Electric Corporation's new ROTAMASS LR flowmeter employs a proven dual bent-tube and self-draining design and represents a significant addition to Yokogawa's ROTAMASS low flow line product family for gas and liquid flow measurement.
Designed to measure both liquids and gases, the effective turndown of the ROTAMASS LR is no less than 2000:1 for liquids and 5000:1 for gases, and the mass flow measurement range spans from 10.5g/h up to 40kg/h, achieving a measurement accuracy of +/-0.15 per cent of reading for liquids and +/-0.5 per cent for gases.
The Coriolis flowmeter market continues to grow, and a number of market research reports have identified increasing demand for smaller devices with a 2-inch bore diameter or less. There is also rising demand for low-flow measurement solutions that achieve high accuracy and stability. The majority of small Coriolis flowmeters on the market currently use single-tube detectors, which have been shown to be less accurate and stable under conditions that include vibration and changes in the ambient or fluid temperature. To meet the market’s need for accurate and stable measurement of fluids at low flow rates, Yokogawa has developed this low flow Coriolis flowmeter based on its proven dual bent-tube detector design.
The ROTAMASS LR employs a dual bent tube that optimally decouples the core measuring element from process vibration that can cause fluctuating zero stability and reduced measurement accuracy. When fluid density changes, a single-tube Coriolis flowmeter can become imbalanced and start to behave like an emitter. The ROTAMASS LR remains balanced because of the equal mass change in both tubes and the absence of interference from the process piping. By design, it is insensitive to fluctuations in the ambient temperature and achieves excellent zero stability under changing process conditions. The two tubes are made from C-22 alloy, which is less susceptible to thermal expansion than conventional stainless steel.
Measuring tube temperature plays a key role in mass flow and density measurements. Normally it is more difficult to measure temperature with Coriolis flowmeters that have tubes with a smaller surface area. The ROTAMASS LR solves this problem by using an inline temperature sensor, ensuring exact and fast measurements in process temperatures ranging from -50degC to +150degC, claimed to be a unique feature in the low flow Coriolis flowmeter market.
Stainless steel secondary containment
ROTAMASS LR sets a new safety standard in the low-flow market, with a gas-tight, all-stainless steel secondary containment that can handle pressures up to 65bar. The ROTAMASS LR can be used in high-pressure applications up to 400bar. A huge variety of welded process connections are available. Unlike most flowmeters on the market today, gaskets are not used, minimising the risk of leaks.
For the prevention of fluid component separation and gas condensation, insulation and a heat jacket are available as an option.
Takashi Nishijima, a Director and Senior Vice President, and Head of Yokogawa's Industrial Automation Platform Business Headquarters, comments: "By measuring and controlling very low flow rates with a high level of precision, Yokogawa is helping its customers to realise the company's VigilantPlant concept. We believe that this newly developed product gives customers a wider range of choices in multivariable process measurement and allows for greater accuracy and steady measurement in their utilisation."
Major target markets include chemical research laboratories, chemical plants and pharmaceutical plants, with applications including liquid and gas low flow measurement, high pressure gas pipelines, chemical injection, micro dosing systems, metering pump control, blending, precision coating, and vacuum thin-film coating.
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