Cup viscosity test

Test for making flow comparison under strictly comparable conditions. The cup viscosity test employs a cup-shaped gravity device that permits the timed flow of a known volume of liquid passing through an orifice located at the bottom of the cup. 

Because of the simplicity of the test and its ability to be used alongside mixing equipment, the cup viscosity test is ideal for mixing resinous solutions or making adjustments of solvent to existing solutions to obtain a specified viscosity. 

As the name implies, cup viscosity tests employ a cup-shaped gravity device that permits the timed flow of a known volume of liquid through an orifice located at the bottom of the cup. Under ideal conditions, this rate of flow would be proportional to the kinematic viscosity that is dependent upon the specific gravity of the draining liquid. However, the conditions in a simple flow cup cannot be considered ideal for true measurements of viscosity. Cup viscosity tests, however imprecise, are practical, easy-to-use instruments for making flow comparisons under strictly comparable conditions (2,3). 

A number of closed-cup, flash test procedures cm be used, depending on the viscosity of the liquid under investigation. 

There is no entirely satisfactory way of measuring flow. In the BS 2782 flow cup test an amount of moulding powder is added to the mould to provide between 2 and 2.5 g of flash. The press is closed at a fixed initial rate and at a fixed temperature and pressure. The time between the onset of recorded pressure and the cessation of flash (i.e. the time at which the mould has closed) is noted. This time is thus the time required to move a given mass of material a fixed distance and is thus a measure of viscosity. It is not a measure of the time available for flow. This property, or rather the more important length of flow or extent of flow, must be measured by some other device such as the flow disc or by the Rossi-Peakes flow test, neither of which are entirely satisfactory. Cup flow times are normally of the order of 10-25 seconds if measured by the BS specification. Moulding powders are frequently classified as being of stiff flow if the cup flow time exceeds 20 seconds, medium flow for times of 13-19 seconds and soft flow or free flow if under 12 seconds. 

Plastic Viscosity and Yield Point. Plastic viscosity and yield point measurements are obtained from a direct indicating viscometer. Due to the temperature effect on the flow properties of oil-base mud, the testing procedure is modified. The mud sample in the container is placed into a cup heater [23]. The heated viscometer cup provides flow property data under atmospheric pressure and bottomhole temperature. 

As the name implies, the cup-and-bob viscometer consists of two concentric cylinders, the outer cup and the inner bob, with the test fluid in the annular gap (see Fig. 3-2). One cylinder (preferably the cup) is rotated at a fixed angular velocity ( 2). The force is transmitted to the sample, causing it to deform, and is then transferred by the fluid to the other cylinder (i.e., the bob). This force results in a torque (I) that can be measured by a torsion spring, for example. Thus, the known quantities are the radii of the inner bob (R ) and the outer cup (Ra), the length of surface in contact with the sample (L), and the measured angular velocity ( 2) and torque (I). From these quantities, we must determine the corresponding shear stress and shear rate to find the fluid viscosity. The shear stress is determined by a balance of moments on a cylindrical surface within the sample (at a distance r from the center), and the torsion spring ... 

This method covers the decn of the flash point, by Tag closed tester, of liquids with a viscosity of below 45 SUS at 100F (37.8 C) and a fl pt below 200 F (93 C) except cut-back asphalts and those liquids which tend to form a surface film under test conditions Note 1 For the closed cup fl pt of liquids with... 

Tag closed tester—apparatus for determining the flash point of petroleum liquids having a viscosity below 5.8 centistokes (cSt) at 37.8°C (100°F) and a flash point below 93°C (200°F), under test methods prescribed in ASTM D 56. The test sample is heated in a closed cup at a specified constant... 

Standard Test Method for Viscosity by Dip-Type Viscosity Cups, ASTM Designation D 4212-... 

PM2 5 PM10 PMA PMC PNA Pour point Particulate matter less than 2.5 ptm and 10 jam in diameter. Polymetacrylate viscosity index improver or viscosity modifier. Pensky-Martin closed cup-flash point test. Polynuclear aromatic. Measure of lubricant low-temperature flow which is 3°C above the temperature at which a normally liquid petroleum product maintains fluidity. Oil forms a honeycomb or crystals at low... 

Another test for determining the viscosity of liquid adhesives measures the time it takes the test liquid to flow by gravity completely out of a cup with a certain size hole in the bottom. These consistency cups are designed to expel 50 mL of sample in 30 to 100 s under controlled temperature and relative humidity conditions. The number of seconds for complete flow-out of the sample is determined. There are different cup volumes and hole sizes... 

The mixing procedure used in this test, that is, 60 s in a high-shear Waring Blendor, is intended to produce maximum disintegration of the stucco particles [6j. The viscosity of a slurry mixed by this method if measured by a Ford cup viscometer, and the water solid ratio with which a specified flow time is obtained is taken as the consistency. 

Texture analyzers are also used to assess deformability of a fluid, using penetration force vs. depth profiles, etc. These instruments in addition to Brookfield and Haake viscometers are common QC metrics. Other methods include viscosity flow cups and bubble or falling ball viscometers, and several relevant standard test methods include ASTM D1200, DIN/ISO 2431, ASTM D5125, BS3900 Part A6, ASTM D1545, and ASTM D1725. 

Measurement of the run-out time from flow cups has been adopted worldwide since this test can be performed anywhere (e.g., in the laboratory, during production, or on a building site). Nationally standardized sets of flow cups are normally used in major industrial countries and give similar but not identical results. An internationally standardized system of flow cups has been introduced (ISO 2431) to overcome this problem. Since temperature fluctuations greatly affect the viscosity measurement, the flow cups should only be used in conjunction with thermostated jackets. 

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