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Cannon-Fenske Routine Viscometers (For Transparent Liquids) This is the most widely used type of glass capillary kinematic viscometer tube for measurements of fluids with Newtonian flow behavior as described in ASTM D445 and D446, with precision of +/- 0.2%. Approximately 7 ml of sample is required to fill the tube. To fill, the tube is inverted, and sample is suctioned into the double bulb section to the final timing mark. After the tube is returned to upright position and sample has descended into the reservoir, the unit is equilibrated in a bath at 40°C for 15-20 minutes. Viscosity of the sample is determined by pressuring the sample upward, timing the flow between timing marks on descent, and multiplying this time (in seconds) by the Constant of that specific viscometer tube. Successive timings may be done to confirm accuracy of the time factor. Each viscometer tube has a permanent serial number and is supplied with a calibration certificate indicating the constant of that tube at 40°C and 100°C. Select the tube needed from the ranges indicated below: Ordering Information
Special Sizes and Special Constants are available
upon request. SIL Viscometers (For Transparent Liquids) These viscometers require about 34 to 35 ml of sample which is overfilled into the reservoir, and then the excess suctioned away after thermal equilibration to leave a constant automatic level remaining. Thereafter, the sample is suctioned or pressured upward and the meniscus timed as it descends past two timing marks. The time, in seconds, multiplied by the constant of this tube with permanent serial number (supplied with certificate) determines the viscosity of the sample being tested. The timing may be repeated as often as necessary to confirm a constant value. Precision = +/- 0.2% Ordering Information
Special Sizes and Special Constants are available
upon request. Cannon-Manning Semi-Micro Viscometers (For Transparent Liquids) This type of viscometer is useful in situations where available sample is limited since viscosity can be determined with 1ml of sample. The tube is filled by inverting and suctioning the sample into the capillary side. Then the tube is returned to normal vertical position, equilibrated in bath before drawing or pushing liquid upward and timing meniscus as it descends between the timing marks. Successive timings may be performed, and the average time in seconds, multiplied by the Constant of this serialized tube will result in the viscosity of the given sample. Ordering Information
Special Sizes and Special Constants are available upon request. Ubbelohde Viscometers (For Transparent Liquids) This is a suspended level type viscometer that requires approximately 11ml of sample which is filled into the reservoir to a level between two lines. The Ubbelohde design ensures a uniform driving head of liquid independent of sample volume, making the viscometer Constant the same at all temperatures. After temperature equilibration in the bath, sample is pressured or suctioned into the volumetric chamber with air vent arm closed. The the air vent arm is opened to allow receiving chamber to clear and empty before timing of the meniscus of the sample as it descends. Repetitive timings may be done in succession, and the average time in seconds, when multiplied by the Constant stated on the certificate of this serialized tube, will equal the viscosity of the sample. Ordering Information
Special Sizes and Special Constants are available
upon request. Cannon-Ubbelohde Viscometers (For Transparent Liquids) This is a suspended level design very similar to the Ubbelohde Viscometer except for a different geometry at the top for the air venting passage which makes this design somewhat more durable. Operationally, it is the same as the Ubbelohde, but the values of the Constants and exact measuring ranges are slightly different. Each tube has a permanent serial number and is supplied with a calibration certificate which bears the official Constant for that tube. When the drop time of the sample is determined (average repetitive timings), the value in seconds is multiplied by the Constant to obtain the viscosity of the sample in Centistokes (cSt). Ordering Information
Special Sizes and Special Constants are available upon request. Cross-Arm Viscometers (For Transparent and Opaque Liquids) The Cross-Arm operates differently than the modified Ostwald and suspended- level designs in that the liquid sample is caused to flow through a capillary restrictor, and then into a volumetric timing bulb which is clean and dry, and has not previously been wetted by the sample. For this reason, only one timing may be done per sample. In order to repeat a test, the tube must be thoroughly cleaned with solvent (such as Acetone), using a vacuum to move the solvents, and finishing the passage of dry air until the tube is completely dry and ready for the next sample. Approximately 3ml of sample is introduced into the large tube at the top while viscometer is mounted in the bath. Sample level is controlled to a point just under the fill line of the siphon tube. After equilibration, the liquid is pressured slightly over the siphon point, through the restrictor, and into the timing bulb. Ordering Information
Special Sizes and Special Constants are available upon request. Cannon-Fenske Opaque Viscometers (For Opaque Liquids) These are reverse flow type mostly used with dark samples that would obscure the timing lines of other tube configurations. Since the sample is timed as it ascends to the timing marks, it is possible to test very dark samples. Approximately 11ml of sample is suctioned into the reservoir bulb while the tube is inverted, and then the stem is returned to upright position and equilibrated in the bath. After equilibration, the stopper is removed and sample flows downward into first bulb, then upward into two timing bulbs where two timings may be done on the same sample. The certificate on this serialized tube contains calibrated Constants for both the Lower and Upper bulbs, so that dual viscosity data may be secured by multiplying the two timings with their respective constants. Ordering Information
Special Sizes and Special Constants are available upon request. Other Viscometers Available The viscometer tube listed previously are the most commonly used types and sizes, and are most always in-stock items. ASTM D446 describes many other types of viscometer tube, as listed below. These tubes are available from Greers Ferry Glass Works based on your size and type specification.
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