Vibrating Wire Viscometer with Wire Diameters of (0.05 and 0.15) mm: Results for Methylbenzene and Two Fluids with Nominal Viscosities at T = 298 K and p = 0.01 MPa of (14 and 232) mPa·s at Temperatures between (298 and 373) K and Pressures below 40 MPa

A vibrating wire viscometer has been developed with an electrically insulating tensioning mechanism. It has been used with two wires, one of diameter 0.05 mm the other of diameter 0.15 mm, to measure the viscosity of methylbenzene and two reference fluids with viscosities of (14 and 240) mPa·s at T = 298 K and p = 0.1 MPa at temperatures in the range from (298 to 373) K and pressures below 40 MPa, where the viscosity covers the range from (0.3 to 100) mPa·s with an uncertainty of < 0.6 %. The results so obtained differ from literature values by < 1 %. Measurements with the 0.150 mm diameter wire at T = 301 K demonstrate that the upper operating viscosity is 200 mPa·s with an uncertainty of about 3 %.