Endress+Hauser introduces the Liquiphant M, a density meter that provides on-line measurements, eliminating the need for extensive and expensive off-line procedures and laboratory measurements. A built-in density calculator can be end user customized with complex tables and mathematical interdependencies, allowing the meter to provide the same kind of density and concentration measurements once possible only with lab instruments.
Because the Liquiphant M provides on-line measurements, it allows control systems to react much faster to changing process conditions. Instead of waiting for results to come back from the lab, a control system can take corrective action immediately by performing closed-loop control.
Calculating Density
The Liquiphant employs a mechanically oscillating fork with two tines that are each excited to resonant frequency. The frequency changes when the fork is immersed in any liquid. If the vibration falls below a predetermined frequency, the sensor reports the covered state to a subsequent switching electronics. The tines are excited by a piezoelectric drive. The resonant frequency depends on the moment of inertia of the fork as well as the membrane stiffness, and the frequency measures approximately 1000-1200Hz in air.
Changes in resonant frequency are directly interrelated with the density of the medium. In a lower medium density, such as liquefied gas, the resulting resonant frequency is higher than in more pronounced densities like water. The electronics of the Liquiphant can measure this change in the resonant frequency. The density of the medium can also be calculated taking temperature and process pressure into consideration.
Because the Liquiphant M provides on-line measurements, it allows control systems to react much faster to changing process conditions. Instead of waiting for results to come back from the lab, a control system can take corrective action immediately by performing closed-loop control.
Calculating Density
The Liquiphant employs a mechanically oscillating fork with two tines that are each excited to resonant frequency. The frequency changes when the fork is immersed in any liquid. If the vibration falls below a predetermined frequency, the sensor reports the covered state to a subsequent switching electronics. The tines are excited by a piezoelectric drive. The resonant frequency depends on the moment of inertia of the fork as well as the membrane stiffness, and the frequency measures approximately 1000-1200Hz in air.
Changes in resonant frequency are directly interrelated with the density of the medium. In a lower medium density, such as liquefied gas, the resulting resonant frequency is higher than in more pronounced densities like water. The electronics of the Liquiphant can measure this change in the resonant frequency. The density of the medium can also be calculated taking temperature and process pressure into consideration.
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