Patent ID: 7966863
Filing Date: 2011-06-28
Classification: G01F,G01N

Abstract:
1. A method for generating a viscosity value by means of a metering device, said viscosity value representing a viscosity of a fluid flowing in a pipe, said metering device comprising a vibratory transducer and a meter electronics electrically connected to said transducer, said transducer including at least one flow tube communicating with the pipe for conducting the fluid, and an excitation assembly mechanically coupled to the at least one flow tube, and said meter electronics including a driver circuit electrically connected to said excitation assembly, said method comprising: generating an oscillating excitation current by means of said driver circuit of the meter electronics; feeding said excitation current into the excitation assembly; vibrating said at least one flow tube conducting said fluid; sensing vibrations of said at least one flow tube for generating at least one sensor signal representing vibrations of said flow tube; generating from said at least one sensor signal an amplitude control signal representing an amplitude of said oscillating excitation current to be adjusted and an frequency control signal representing a frequency of said oscillating excitation current to be adjusted; using said amplitude control signal and said frequency control signal for controlling said driver circuit of the meter electronics; deriving from at least one of said amplitude control signal and said frequency control signal an intermediate value, which represents vibration-damping friction forces in the fluid; and using said intermediate value for determining the viscosity value.