Laray Viscometer

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Laray Viscometer is an instrument applicable to determine the rheological properties ( apparent viscositya pseudo yield valuea shortness, etc ) of Non-Newtonian liquids (viscosity increases with shear rate). Larya Viscometer designed and produced by our company is in accordance with the specification of ASTM D 4040-10 and ISO12644: 1996(E) Graphic technologya Determination of rheological properties of paste inks and vehicles by the Falling Rod Viscometer . Its principle: measuring fall times by loading the rod with different load weights pass the gap which is filled with the test fluid. By applying linear regression methods & by means of suitable flow model ( Casson model, Bingham model or Power Law model ) to obtain apparent viscositya yield valuea shortness ratio of sample.

ISO12644

Graphic technology -- Determination of rheological properties of paste inks and vehicles by the falling rod viscometer. This International Standard specifies the procedure for determining the viscosity and yield value of paste inks and vehicles which are unreactive under normal room conditions. It is applicable to inks in the apparent viscosity range of 2 Pa A. s to 200 Pa A. s.

ASTM D 4040-10

Standard Test Method for Rheological Properties of Paste Printing and Vehicles by the Falling-Rod Viscometer. Apparent viscosity at the relatively high shear rate of 2500 sa 1 does not completely define the rheological properties of printing inks but is useful in the practical control of ink viscosity during production and the specification acceptance between supplier and purchaser.

The slope of the power law plot is the preferred measure of non-Newtonianism. The yield value, which is obtained by extrapolation of high-shear measurements to a shear rate approaching zero, does not conform to the definition of the true yield stress. The yield value and other low shear parameters are also subject to a high degree of variability


a Input voltage: 220V 50Hz
a Range of apparent viscosity: 2-200Pa.s
a Dimensions of the falling rod: I l2x300mm
a Weight of the falling rod: 132g
a Sets of load weights (total 4075g ): 25-50-100-200-200-500-1000-1000-1000g
a Overall dimensions: 140mmA 140mmA 300mm (length by width by height )
a Weight( including instrument weight box controller ): 18kg

Test procedure
1. Prior to use, the test sample (about 5g) shall be kneaded by a spatula and equilibrated to test temperature. The sample shall be homogeneous and not contain any coarse particles. An amount of the test sample sufficient to coat the rod and aperture is applied to the lower part of the rod.

2. The bottom of the rod is inserted into the aperture of guide bush and slightly fall on the turntable, the sample is distributed uniformly around the gap, the gap is filled with the test fluid which is sheared when the rod falls by using fingertip; lift the bottom of the rod 20mm, then fall on the turntable.

3. Load weights to be loaded on top of the rod, remove a turntable to let falling rod fall, the rod and the aperture are wetted by the liquid; Make sure that photoswitch & temperature sensor are working normally (temperature indicator display starting temperature when starting falling, time indicator starts to display seconds; temperature indicator display finishing temperature when finishing falling, time indicator display actual fall time; temperature resume to display actual temperature of guide bush after pulling up the rod, time automatically clear.

4. Avoid any scoring operation for the rod, the metal spatula should not be allowed operation for the rod; Dona t do falling operation under the condition of no test sample. After finishing falling, the rod is lightly pulled up and rested on the support. After each run, the rod is scraped with the spatula and the liquid which was scraped off is reapplied on the lower part of the rod & the aperture of guide