1/7/2024 0 Comments Used viscosity meter![]() There are two types of viscosity measurement:īehavioural where it is the viscosity at process conditions that is important, Now if we also have a viscous behaviour where work history has an effect then it gets even more problematic. However, while in the lab with a fixed sample, the only shear on the fluid is that created by the rotating cylinder or bob, in the process there is the added shear due to flow. The argument is that shear dependent behaviour requires a constant shear viscometer (e.g. Non-Newtonian fluids usually result in differences of opinion even between manufacturers. These also measure the density which enables them to convert the measured dynamic viscosity into kinematic. Most vibrating element viscometers only measure dynamic viscosity, the exceptions are the Emerson 78 viscometers and the Lemis VDC 52 ViscoAnalytic. In the lab a capillary viscometer measures kinematic viscosity because it is the time taken for the fluid to flow through the capillary under gravity. This is because this uses the pressure drop at a constant flow rate to determine viscosity. For example, using a process capillary viscosity analyser. It is usually necessary to include density if you want kinematic viscosity. This includes capillary, rotational and vibrational types. In my experience, most process viscometers measure dynamic viscosity. Well, you can go down the route of using a proprietary viscometer. The time it takes for the level to drop x% out of the cylinder and into a drain would then be correlated to the laboratory viscosity measurements.Īny ideas or suggestions would be much appreciated. If I'm unsuccessful with finding a meter, I was thinking of designing a slip stream off of the process that enters a large cylinder (maybe a few gallons in size) with a level indicator on it. Has anyone had success using any type of automated viscosity measurement at all? I suppose such an idea would be acceptable if my budget was increased by a factor of 10. Brookfield only sells inline kinematic viscosity meters, which would only be useful if I then bought a density meter, which I do not want to do!Įndress+Hauser quoted me $25k for a coriolis meter that measures dynamic viscosity, but I'm told the results of the instrument are extremely dependent upon how it's calibrated at the factory and can only be used for the fluid it was calibrated for. This of course would be an apparent viscosity, but if measured as normal viscosity it will be OK regardless of the gel being non-newtownian (thus the definition of apparent viscosity). ![]() ![]() Gel strength is also directly read as dial readings in oilfield units of lbm/100 ft 2.I'm looking for an inline viscosity meter for gels. For example, at 300 rpm, the dial reading (511 sec –1) is a true viscosity.īingham plastic rheological parameters are easily calculated from direct-indicating viscometer readings: PV (in units of cP) = 600 dial - 300 dial and YP (in units of lbm/100 ft 2) = 300 dial - PV. It is called "direct-indicating" because, at a given speed, the dial reading is a true centipoise viscosity. Two speeds of rotation, 300 and 600 rpm, are available in all instruments, but some are 6- or variable-speed. The direct-indicating viscometer is a rotational cylinder and bob instrument. Also known as direct-indicating viscometer or V-G meter, an instrument used to measure viscosity and gel strength of drilling mud. ![]()
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