| DARK COLORED OILS: Dark colored oils in the test tube may make it difficult to see the sphere. To overcome this, follow standard test procedure under READING. Then, with your back to the light (Fig. 6) and full light on the scale, (Fig. 7 & 8) tilt reference tube toward you 90 degrees to bring the sphere in the test tube into sight. The point on the scale corresponding to the position of the sphere indicates the viscosity of the test oil direct at which it was rated in Centistokes at 40° C. (Fig. 8) The VISGAGE is designed and constructed to test the viscosity of new and used oil/s but not sludge.
Whenever the sphere in the test tube can no longer be seen, you will know the oil is so badly fouled with contaminants that it needs to be changed immediately or cleaned by any of the appropriate cleaning methods. VISCOSITY INDEX (VI): The reference tube contains certified oil with a viscosity index of 95 VI. Best accuracy is achieved when the oil being tested has a VI near the VI of the reference oil, and several identical readings on the scale indicate temperatures of both tubes are equal. If the VI's of the oils are far apart (for example, 95 VI in reference tube, 40 VI in test oil), warm VISGAGE to 40° C, and then take readings. |