Brookfield viscosimeter

Carrots (Boleo) were peeled by 2% NaOH at 88-96°C for 4 minutes, minced by a meat mincer (2 mm) and homogenised for 2 minutes by an ULTRA-TURRAX T25 homogenizer (from Jahne Kunkel). The carrot mash was preheated to 45°C (20 minutes) before the enzyme preparations, 25 mg enzyme protein/kg mash, were added. The enzymes were dissolved in water to give a dilution of 5% (v/v) of the carrot mash. The mash was incubated at 45°C under stirring (60 rpm) for 2 hours, before the enzymes were inactivated at 86°C for 5 minutes in a microwave oven. Finally the purees were homogenised for 1 minute by ULTRA TURRAX. The viscosity of the puree was measured by a BROOKFIELD viscosimeter Model DV-n + with spindle A from HELIPATH SPINDLE SET at 2.5 rpm thermosta-ted at 50°C. The stability of the puree was measured as the sediment (in %) after centrifugation in 10 ml tube a 1660 x g for 10 minutes. 

The oligo-polyol s viscosity is determined using a Brookfield viscosimeter. The Standard Test Method for oligo-polyol viscosity determination is ASTM D4878 [37]. There are two test methods, A and B, applicable for viscosities between 0.01 to 1000 Pa-s, at 25 °C, or for solid polyols (such as polytetrahydrofuran), at 50 °C. Test method A is indicated for oligo-polyols of very high viscosities. 

The fluids used for core saturation and injection were prepared as explained below. The properties of these fluids are shown in Table II. Note that all the viscosity measurements were made on a Brookfield viscosimeter at 6-RPM (6.57 s ) to preserve the consistency among the measured values,... 

There are roughly three classes of viscosimeters available the capillary viscosimeter, the rotational viscosimeter, and the falling-ball viscosimeter. Both the capillary and the rotational viscosimeters are built in different versions that allow for the exact determination of the viscosity in well-defined flow fields. Especially rotational viscosimeters allow the exact adjustment of a constant flow profile, thus are available in high precision and expensive versions as rotational rheometers. Capillary viscosimeters are the best compromise between the exact determination of viscosity and a well-priced measurement device, and are therefore the most commonly found type of viscosimeters. Both rotational and capillary viscosimeters are available in simple and inexpensive versions as Brookfield viscosimeters and flow... 

Brookfield viscosimeters also belong to the group of rotational viscosimeters. In contrast to the devices described earlier, this viscosimeter does not generate a defined shear field. The Brookfield viscosimeter consists mainly of a disc or a pin that is rotating with a defined velocity in the sample fluid. The torque that is required to achieve this rotational speed directly yields a viscosity through comparison with a calibration fluid. The range of measurable viscosities can be adjusted by variation of the disc geometry. 

Nevertheless, Brookfield viscosimeters are the widely used devices for quality management they are a fast and cheap alternative for conducting one-point measurements. In addition to this, many companies use special stirring systems that are custom tailored for a specific application. However, for the determination of the intrinsic viscosity or an exact viscosity devices like the Brookfield viscosimeter are not appropriate. 

The dynamic viscosity of pol5mier solutions of various compositions was measured as a function of PHB concentration with Heppler and Brookfield viscosimeters. The electrical conductivity of pol5mier solutions was calculated by the equation X = o/R, Ohm cm the electrical resistance was measured with E7-15 instrument. 

Viscosity Stormer viscosimeter (ASTM D562-81) and Brookfield viscosimeter (ASTM 2196-86)... 

Viscosity measurements are made by Brookfield viscosimeter or Zahn cup. Readings of solids content, as a means of monitoring viscosity and water loss, can be made by refrac-tometer. Manufacturers of glues and compounds can supply customers with viscos-ity/solids and viscosity/temperature graphs. 

Fig. 12 shows the effects of Kelzan M concentration and shear-rate on polymer water viscosity. The effect of shear rate was determined by varying spindle speed on an LVT Brookfield viscosimeter with the U.L. attachment. The decrease in viscosity at high shear rates is desirable from an injectivity standpoint. It is conceivable that polymers having strong friction reducing properties might show higher injectivities than water alone. 

Another well documented, but less widely used method for formulation development is the measurement of electrokinetic properties [14]. These tests require more disdnc-tive/elaborate sample preparation and are mosdy restricted to use during development. Also widely used and relied on are rheological measurements. The scope of rheological measurements ranges from viscosity measurements to the determination of yield points or oscillatory properties, such as the G and G -modules [15]. Since suspoemulsions are not ideal viscous but mostly viscoelastic or dilatant, a wide range of characterization techniques exists. Instrumentation required for this are simple rotary viscosimeters (Brookfield) or more sophisticated stress or shear controlled rotational viscosimeters. 

Viscometer Also called a viscosimeter. This instrument is used for measuring the viscosity and flow properties of fluids such as plastic melts. Basically it is the property of the resistance of flow exhibited within a body of material. A commonly used type is the Brookfield that measures the force required to rotate a disk or hollow cup immersed in the specimen substance at a... 

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