5 replies to this topic

[saeedeh]

I have a project on falling piston & bubble viscometer for my fluid mechanic class, but I have not found anything?
can someone tell me how falling piston & bubble viscometer work?
or introduce me a website or something which could help me with my project?
tnx

[breizh]

Do a minimum work , i.e Google " viscometer types " , you will find plenty of information.
Breizh

[JMW]

For falling piston look at Norcross web site.
For an electro magnetic operation rather than gravity fall, go to Cambridge Scientific.

The falling piston design is one where the piston is able to slide up and down in a cylinder closed at one end and where there is a clearance between the cylinder walls and the piston.
The piston is lifted vertically mechanically and as it does so liquid from the flow stream flows through the tolerance to fill the bottom of the cylinder below the piston.
Once at the top of the lift the piston is released and allowed to free fall. As it falls it triggers a switch or sensor to start a timer. As it reaches the bottom of the cylinder it trips a "stop timer" sensor.
As the piston falls it displaces the fluid in the cylinder which flows back out through the tolerances.
The time taken for the piston to fall to the bottom of the cylinder varies with the viscosity of the fluid.
Very good and accurate with clean fluids but the measurement is cyclic and the response time increases with viscosity.

The Cambridge sensor is very much smaller and the piston is now a shuttle that moves back and forth in the closed end cylinder under the influence of an electo-magnetic force applied by an external coil that is also used as a detector. The average time for a cycle is a function of the viscosity. Again, best with clean fluids but be aware that the electric coil provides some heating effect which can modify the viscosity.

For interest you can compare this type of viscometer to the falling ball viscometer (visit Kittiwake) where it is used as lab instrument to measure viscosity at a precise temperature.

There is an important difference between these viscometers and Stokes law viscosity measurement in that they do not determine terminal viscosity but elapsed fall time from a zero start.

[akslzf]

Google before Cheresourcing.
*http://en.wikipedia.org/wiki/Viscometer
*Instrument Engineers' Handbook in Google books

[kuldeepd]

For calculation purposes, you can use
www.processglobe.com

[Hamedcheng]

I have a project on falling piston & bubble viscometer for my fluid mechanic class, but I have not found anything?
can someone tell me how falling piston & bubble viscometer work?
or introduce me a website or something which could help me with my project?
tnx

Hi
are you iranian??
please see this linke:
www.sofraser.com/viscometer.htm
dictionary.reference.com/browse/vibration%20viscometer
www.askkids.com/web?q=Brookfield+Viscometer
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