Emerson Micro Motion 7829 Viscomaster Dynamic - Principle of Operation

Micro Motion 7829 Viscomaster Dynamic Viscosity Meter 3
Typical applications
• Heavy fuel oil (HFO) heater control to burners
and engines
• Lube oil viscosity control
Typical industries
•Marine
•Power
• Heavy fuel oil (HFO) blending and bunkering
Principle of operation
The 7829 Viscomaster Dynamic viscosity meter
uses vibrating fork technology to measure viscosity.
Viscosity is measured by detecting the bandwidth
around the fork’s natural vibration frequency.
The following figure illustrates how the 7829 meter
uses the frequencies at point A (the lower
–3 db point) and at point B (the upper –3 db point)
to digitally calculate bandwidth and quality factor.
Quality factor is then used to define fluid viscosity
using standard calibration techniques.
Product 1
Product 2
Response
amplitude
Frequency (Hz)
Product 1 – Low Viscosity
Product 2 – High Viscosity
Bandwidth = Point B – Point A
Resonant Frequency = (Point A + Point B) / 2
Quality Factor = Resonant Frequency / Bandwidth