Hi,
I'm a co-op student working at Leitch Technology in Toronto, Canada.
My supervisor has assigned me the task of developing and conducting a study
to analyze the effects of different variables in the handling process we
have for paste here. Variables like exposure to air, amount of stirring
etc.
We have a Malcolm PM-2A handheld viscometer to use, but have a lot of
questions. =)
I've performed a calibration, and done some preliminary trials just to get a
feel for the instrumentation, and of handling paste.
Issues:
1) Calibration seemed to proceed according to the manual just fine, however,
when I finished, and turned the power on, the unit still does not zero
properly and moves up to 4.7 (Pa.s). Is this non-zero value acceptable? or
should I try and re-calibrate?
2) When I try testing the paste, after starting up the unit, it draws paste
up the screws, however the surrounding paste (I assume due to the high
viscosity) does not flow into the void space, and after some time, the head
ends up rotating in the little hole it dug up, without picking up any more
paste. To fix this I've tried oscilating the vial I use to hold the paste
to fill in the void, or try pushing surrounding sample into the hole. As I
do this, the viscosity reading seems to be constantly changing and I'm not
sure at what point should I take a reading.
3) Sometimes it seems like I'm required to lower the unit deeper into the
paste to ensure that it is drawing paste into the flutes. Can anyone
explain why the lip of the opening has to stay above the paste, or what it
is exactly that I should watch out for that would affect the readings.
4) Currently I'm using 60ml glass sample jars (and filling maybe half of it
with paste). I find this very difficult to get paste into the container.
My engineering in training mind has thought of using a conical shaped
container (like a funnel? with a plug in the bottom) to make it easier to
handle. My supervisor was wondering if this was unheard of, or if it was
widely practiced?
Thats it for now, any help would be greatly appreciated.
Toby Chang
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