Talk:Viscometer

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can someone help me fix up the references? --Onionmon 22:27, 28 June 2006 (UTC)

Vibrating element sensors also employ the bandwidth measurement e.g. Mobrey's 7827 and 7829 tuning fork viscometers and VAF's Viscosense viscometers. In these instruments the sensor is vibrated not at the resonant frequency but alternately at the upper and lower 1/2power points (+/-3 dB)by the expedient of driving out of phase (90deg on either side) The difference in frequency is the bandwidth which is a function of viscosity. It should be pointed out that vibrating element viscometers measure the dynamic viscosity and not kinematic. The Mobrey, Sofraser and TDC sensors all displace fluid and thus in each case the resonant frequency changes with density and thus potentially can derive the kinematic viscosity. Torsional viscometers such as VAF's Viscosense, Nametre Hydramotion etc do not displace the fluid thus the resonant frequency is a function only of the mass of the sensor. MeyerMeyer 15:07, 29 June 2007 (UTC)

[edit] Removed innacurate advertising material

I removed the following material:

Vibrating viscometers are rugged industrial systems used to measure viscosity in the process condition. The active part of the sensor is a vibrating rod. The vibration amplitude varies according to the viscosity of the fluid in which the rod is immersed. These viscosity meters are suitable for measuring clogging fluid and high-viscosity fluids even with fibers (up to 1,000,000 cP). Currently, many industries around the world consider these viscometers as the most efficient system to measure viscosity of any fluid, contrasted to rotational viscometers, which require more maintenance, inability to measure clogging fluid, and frequent calibration after intensive use. Vibrating viscometers has no moving parts, no weak parts and the sensitive part is very small. Actually even the very basic or acid fluid can be measured by adding a special coating or by changing the material of the sensor such as 316L, SUS316, Hastelloy, enamel etc... + - Some companies have devices based on vibrating blades or other vessels, following the original designs patented by SOFRASER.

This contains many inaccuracies:

1) Not all vibrating viscometers are "rugged

" (POV) 2) Not all are "precise"...in fact, most are empirical devices in any but strictly Newtonian fluids. 3) Vibration amplitudes do not vary with the viscosity in all, or indeed in most vibrational viscometers. In the Nametre, Brookfield, and other vibrational viscometers the amplitude is held constant. 4) The sensitive part is not "very small" on all vibrational viscometers. Nor would this necessarily be an advantage, particularly in slurries or other suspensions with large particles. How small is "very" small? 5) I am familiar with the patent literature of vibrating viscometers, and most do NOT "follow the original design patented by SOFRASER".

Furthermore, in the interest of fairness, we should either include a representative sampling of advertising sites for ALL types of vibrational viscometers, or none.

The SOFRASER web site contains the following explanation of the instrument's principle:

The active part of this portable viscometer is a vibrating rod held in oscillation by a constant electrical power.

The vibration amplitude varies according to the product's viscosity where the rod is immersed.

The signal converter associated (7000 or 8000x family) allows the vibration and processes the amplitude variations in order to deliver a calibrate viscosity response.

This description adds nothing to the information already in the article, so the purpose of the link can only be commercial spam. Diogenes 05:03, 20 August 2007 (UTC)

[edit] Removed Commercial Links

The commercial links to Rheotec and Rheosys are spam. They offer no elucidation of basic principles. Compare, for instance, to the entries on "Mass Flow Meter" or "Magnetometer". The link on "Mass Flow Meter" points to an enlightening desription of the function of the device, not to advertising material. "Magnetometer" contains no commercial links. Diogenes 19:08, 20 August 2007 (UTC)

[edit] SOFRASER

I've removed this spamming info. The SOFRASER company is spamming its product all over other wikis, see italian article too). Jalo 13:34, 13 November 2007 (UTC)