Wells-Brookfield viscometer

Brookfield has introduced a new digital cone—plate viscometer in two versions. The CAP 1000 is a single speed instrument (12,000 or 3,000 s-1 with 60 Hz current) that upgrades the ICI cone—plate design (ASTM D4287). The CAP 2000 is a multispeed viscometer with a viscosity range of 1-15,000 mPa-s. This instrument covers a wide range of shear rates (166-26,600 s 1) and complements the low shear Wells-Brookfield viscometer. 

Serum viscosity measurements are best performed using a Wells-Brookfield viscometer, which permits measurements at different shear rates and variable temperatures (K36). These measurements are warranted when monoclonal IgM concentrations exceed 40 g/L or when IgA or IgG levels exceed 60 g/L. 

The copolymer solutions were prepared by two methods in the first method, the contents of the flask were diluted with several volumes of deionized water and allowed to stand for periods varying from 24 h to several weeks in order to dissolve the gels. The solution was then dialysed with deionized water for three or four days. The concentration of the solution was determined by precipitation in acetone. In the second method, the contents of the flask were dissolved as described above and were then precipitated into acetone and dried in a vacuum oven at 40 °C for 24 h. The solid polymer was then dissolved in deionized water for subsequent measurements. For semiconcentrated polymer solutions, (1.0 or 0.5 wt%), a Wells Brookfield viscometer was used. The Brookfield viscosity (cp) and shear rate were obtained by direct readout and rotational speed (rpm), using the range table supplied by the manufacturer. 

Slurry Viscosity. Viscosities of magnesium hydroxide slurries are determined by the Brookfield Viscometer in which viscosity is measured using various combinations of spindles and spindle speeds, or other common methods of viscometry. Viscosity decreases with increasing rate of shear. Fluids, such as magnesium hydroxide slurry, that exhibit this type of rheological behavior are termed pseudoplastic. The viscosities obtained can be correlated with product or process parameters. Details of viscosity deterrnination for slurries are well covered in the Hterature (85,86). 

Historically, viscosity measurements have been the single most important method to characterize fluids in petroleum-producing applications. Whereas the ability to measure a fluid s resistance to flow has been available in the laboratory for a long time, a need to measure the fluid properties at the well site has prompted the development of more portable and less sophisticated viscosity-measuring devices [1395]. These instruments must be durable and simple enough to be used by persons with a wide range of technical skills. As a result, the Marsh funnel and the Fann concentric cylinder, both variable-speed viscometers, have found wide use. In some instances, the Brookfield viscometer has also been used. 

Rheological measurements. Routine viscosity measurements were made with a Wells-Brookfield micro-cone and plate viscometer, or a Brookfield LVT(D) viscometer with UL adapter. Viscosity-temperature profiles were obtained using the latter coupled via an insulated heating jacket to a Haake F3C circulator and PG100 temperature programmer or microcomputer and suitable interface. Signals from the viscometer and a suitably placed thermocouple were recorded on an X-Y recorder, or captured directly by an HP laboratory data system. 

Viscosity measurements were made at 25°C and 65% relative humidity with a Wells-Brookfield micro-viscometer equipped with a cone and plate. 

The apparent viscosity of an oil, as determined under test method ASTM D 2983. Since the apparent viscosity of a non Newtonian fluid holds only for the shear rate (as well as temperature) at which it is determined, the Brookfield viscometer provides a known rate of shear by means of a spindle of specified configuration that rotates at a known constant speed in the fluid. The torque imposed by fluid friction can be converted to absolute viscosity units (centipoises) by a multiplication factor. 

There are several ASTM standards relative to specific types of material that are based on the Brookfield viscometer. By taking measurements at different rotational speeds, an indication of the degree of thixotropy of the sample can be obtained. Other fundamental rheological properties can be determined as well. 

Aqueous fluid viscosity Output Mixing Tank and Wellhead Producer wells / after breakthrough Brookfield viscometer LVT and UL... 

The cone and plate viscometer is ideal for determining the absolute viscosity of fluids in a small sample volume. The commercially available cone and plate viscometer (e.g., Wells-Brookfield), a precise torque-measuring system, which consists of a calibrated beryllium-copper spring connecting the drive mechanism to a rotating cone, senses the resistance to rotation caused by the presence of sample fluid between the cone and a stationary flat plate. The resistance to the rotation of the cone produces a torque that is proportional to the shear stress in the fluid. The amount of torque is displayed digitally. A commercially available viscometer is illustrated in Figure 7-3fi. 

Viscosity may be tested by numerous methods using standard equipment. In siniplest form the test for viscosity is carried out by allowing a measured volume of the gum solution to flow by gravity from a pipet provided with a capillary oriflce and noting the time of flow. Viscosity can also be expressed as millipoises or centi-poises, depending upon the type of equipment used. Bloom pipets, Oswald pipets, and Dudley pipets are utilized to determine viscosity, as well as such instruments as the Brookfield, Stormer, and MacMichael viscometers. 

Filtration ratio was computed as the ratio of the time of the second 50 ml to that of the last 50 ml of 250 ml polymer solution flowing through 2 micron Nuclepore filters (47mm) with 80 psi across the filter. Viscosity of the emulsion was measured with a Brookfield model LVT viscometer, using a number 2 spindle. Dilute solutions of the polymer were prepared (500 ppm active polymer in 0.3% NaCl) and viscosities were measured using a Brookfield LVT with UL adapter at 12 RFM. This 500 ppm solution was also used for screen factor and filtration ratio measurements. Filtration ratio measurements, as well as those of the viscosity of the emulsion concentrate and dilute solutions made from it were consistent, whether measured at the field laboratory or at the production plant of the supplier. 

The Brookfield type of viscometer, in which one of a number of different spindle types (RV, LV and so forth) is rotated in the sample dispersion, also enjoys widespread use for viscosity measurements (see ISO 2555 and 1652). The disadvantages associated with this type of viscometer are that the shear rate is not well defined and that the results of measurements made using different spindle types cannot be compared with one another. 

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