Stormer Viscometer Grams to Oz-Inch Conversion

Trying to make sense of the standard stormer viscometer and methods that could be used to calibrate a device, I’ve been looking at the original stormer viscometer in order to get an idea of what ‘grams’ actually means in the case of the stormer viscometer. Here are some facts.

The weight in grams is held on a pulley and pulls on a rotating pulley that is 1.125″ in diameter. That pulley rotates some gears or belts at a ratio of 11:1 (1 rotation of the pulley = 11 rotations of the spindle). Taking the torque applied on the main pulley and dividing it by 11 results in the actual torque to the spindle.

Simply because I use it in these cases, here is the conversion ratio for grams hung on the instrument to oz-inches. Also, one should keep in mind that there is some loss of torque due to mechanical limitations.

oz-inches == .00367056 * grams

therefore, using this formula, a KU meter ranging from 32 grams to 1099 grams ranges from .1174 oz-in to 4.0339 oz-in.

yay! Hopefully someone finds this useful as well. 🙂

Stuff about sensors, a quick post.

Well, I’ve been looking around at torque sensors and found some interesting information. For one though, they are NOT cheap. Keep in mind that these are higher sensitivity sensors but it doesn’t seem to have an overwhelming bearing on the overall price. for example.

Optical, high sensitivity sensor, ~$6000
Magneto-elastic sensor, ~$2000
Strain gage based, ~$4300

While this is expected, it’s still quite a cost on a per-unit basis. interesting.

Another little tid-bit I picked up is this.
Magneto-Elastic sensor document

Anyways, I’ll keep looking for a cheaper unit, though, I doubt I’ll find one cheaper than the unit I developed. Perhaps I’ll machine a small enclosure with precision bearings and develop a more robust and practical design. I have some conductive graphite for the brushes in order to reduce noise and the brushes could be replaceable. Might try it.