There is one in the latest Machinery Lubrication magazine. Don't know anything about it, but it looks fairly simple. I havent been to the website yet. Ad says:
Visgage, Test Oil Immediately. Direct readings in Centistokes or Saybolt Universal Seconds. No stop watched, thermometers, or calculations.
The visgage is manufactured by the Louis C. Eitzen Col in Glenwood Springs, Colorado.
However, please keep in mind this is *not* ASTM level viscosity reading! It is useful as a gauge as to whether you have a 90 weight or a 10 weight. It is very temperature and operator sensitive. Three people can get three very different readings..
So, please be cautioned that this is not the endall beall for viscosity checks.. A wonderul aid, very useful but with significant limitations, from my person experience of many years of using the Visgage..
George Morrison, STLE CLS
Viscosity guages are a lot less important than they used to be. Probably good to get an idea of what is in a hydraulic system or gear box if you are new and have no idea, but for motor oils they have a questionable use. I've seen dozens of samples of local oils that have lost a significant part of their viscosity in short times, then thickened up. But I almost can't get a good oil to lose viscosity, and have to keep them in way longer than reasonable (500 + hours in a tractor) to get any movement upwards on a good group I, Delo I can't get to thicken even at 1200 hours.
I used the Eitzen Visgage a lot over about 15 years. The one I had came in a great wooden carry case with good closing clips. These are delicate, they do make a mess if the tube which is filled with oil breaks.
They are pretty good, I usually got well within 5% of the eventual UOA viscosity. I used them a lot to detect oil dilution in large diesel engines. Its a lot easier to detect fuel dilution in an SAE 40 than in a multigrade, but if your multigrade is a good one which doesn't oxidise and thicken or shear down (like DELO 400) then you can work with multigrades as well - you just need the 40°C viscosity to check against.
Its been a couple of years since I used one but here are some thoughts.
I think the viscosity comparison it gives is at 40°C.
It works by comparing the roll of a ball in the sample tube against the roll of a ball in a tube filled with a standard oil. Don't tilt it too much, and level if off as the first ball nears the mark.
If you're checking a used oil which is dark, turn the visgage upside down so you can see the point of the ball rolling on the glass tube.
Give the sample tube a good pump when emptying it out, you don't want to leave too much of the last sample in the tube. I used to clean mine out regularly by filling the sample tube with diesel, followed by a few fills/empties with a clean engine oil.
But most importantly, load the sample tube then leave it for 1/4 or 1/2 an hour (the longer the better) for the temperatures to stabilise. You'll get an incorrect reading if your sample oil is at a different temperature to the oil in the standard tube.
If you are dealing with a customer or problem solving out in the field, if you explain that you've got to let the oils reach the same temperature then you get to spend some time talking things over. If you're trying to solve a problem then its amasing how often extra information which will highlight the answer will come out in a relaxed discussion.
[ June 10, 2004, 05:33 PM: Message edited by: SteveS ]
You might try Forma Scientific, there is a plant here in Marietta, OH. The ones I have expierience with were for asphalt products. These get pretty complicated overall, but give good repeatable results. Just to give you some idea of what was involved with the ones for asphalt:
The product was held at a constant, elevated temp for about 12 hours.
The viscosity tubes were submerged in hot/clear silicone fluid to keep the temp constant while flowing through the orfice.
The viscosity tubes were glass, with a specific opening, a small bulge for a reservoir, then back to a small tube so movement of the flow through the tube was redily apparent.
The viscosity tubes had scribe marks where the timer was started and stopped as the visible flow passed the marks.
Once the sample was introduced into the tube, a constant, electronically controlled vacuum was held on the tube to move the product through the tube.
After the test was finished, it had to be cleaned spotless. This was done by flushing, soaking and sucking clean trichloethelene through the tube.
A calculation was performed that correlated the amount of flow through the orfice over the measured time under constant temp. and vacuum to determine the viscosity. The calculations included compensation for atmospheric pressure.