Cannon-Fenske

Fig. 24. (a) Ostwald glass capillary viscometer, (b) Cannon-Fenske viscometer, and (c) Ubbelohde viscometer. 

The Cannon-Fenske viscometer (Fig. 24b) is excellent for general use. A long capillary and small upper reservoir result in a small kinetic energy correction the large diameter of the lower reservoir minimises head errors. Because the upper and lower bulbs He on the same vertical axis, variations in the head are minimal even if the viscometer is used in positions that are not perfecdy vertical. A reverse-flow Cannon-Fen ske viscometer is used for opaque hquids. In this type of viscometer the Hquid flows upward past the timing marks, rather than downward as in the normal direct-flow instmment. Thus the position of the meniscus is not obscured by the film of Hquid on the glass wall. 

Measured ia 95% ethanol at 25°C usiag an Ostwald-Cannon-Fenske viscometer. 

Capillary viscometers are simple and inexpensive. They are normally constructed from glass and resemble a U-tube with a capillary section between two bulbs. The initial design originated with Ostwald and is shown as part A in Figure 3.2-1. The Cannon-Fenske type, a popular modification of the Ostwald design that moves the bulbs into the same vertical axis, is shown as part B in Figure 3.2-1. 

Figure 3.2-1 Diagrams of (A) Ostwald and (B) Cannon-Fenske capillary viscometers.

Pectin lyase (PNL) activity was measured spectrophotometrically by the increase in absorbance at 235 nm of the 4,5-unsaturated reaction products. Reaction mixtures containing 0.25 ml of culture filtrate, 0.25 ml of distilled water and 2.0 ml of 0.24% pectin from apple (Fluka) in 0.05M tris-HCl buffer (pH 8.0) with ImM CaCl2, were incubated at 37 C for 10 minutes. One unit of enzyme is defined as the amount of enzyme which forms Ipmol of 4,5-unsaturated product per minute under the conditions of the assay. The molar extinction coefficients of the unsaturated products is 5550 M cm [25]. Also viscosity measurements were made using Cannon-Fenske viscometers or Ostwald micro-viscosimeter, at 37°C. Reaction mixtures consisted of enzyme solution and 0.75% pectin in 0.05 M tris-HCl buffer (pH 8.0) with 0.5 mM CaCl2. One unit is defined as the amount of enzyme required to change the inverse specific viscosity by 0.001 min under the conditions of reaction. Specific viscosity (n p) is (t/to)-l, where t is the flow time (sec) of the reaction mixture and t is the flow time of the buffer. The inverse pecific viscosity (n p ) is proportional to the incubation time and the amount of enzyme used [26]. Units of enzyme activity were determined for 10 min of reaction. 

The total activity of the enzymatic mixture was determined from the percentage reduction of viscosity [12] during the depolymerization of solutions, buffered at different pH values, containing 1 % (w/v) of the polygalacturonic acid or 0.5% (w/v) of pectin. A Cannon-Fenske viscosimeter, (ASTM series n° 150) kept at the constant temperature of 25 °C, was used to carry out the tests. 

The [ n] values of all polymers were measured with a Cannon Fenske type capillary viscometer. 

Assays. Nitrogen assays to determine 1-amidoethylene unit content were done by Kjeldahl method. Limiting viscosity numbers were determined from 4 or more viscosity measurements made on a Cannon-Fenske capillary viscometer at 30°C. Data was extrapolated to 0 g/dL polymer concentration using the Huggins equation(44) for nonionic polymers and the Fuoss equation(45) for polyelectrolytes. Equipment. Viscosities were measured using Cannon-Fenske capillary viscometers and a Brookfield LV Microvis, cone and plate viscometer with a CP-40, 0.8° cone. Capillary viscometers received 10 mL of a sample for testing while the cone and plate viscometer received 0.50 mL. 

Viscosity measurements were carried out using Cannon-Fenske viscometers of appropriate capillary diameter so as to keep the efflux time between 200-300 seconds. Approximate shear rate at the wall was calculated using the equation... 

The measurements were performed in an Ostwald Cannon-Fenske viscometer (No. J-627-25) using the method described by Silberberg and Klein Ci). This involves determining the time of flow as a function of the amount of liquid in the viscometer. Amounts between 7 and 8 g are chosen and the viscometer weighed to determine the exact amount. Buffer replacements were undertaken by dilution. 

Canned motor pumps, 27 76-78 Canned pet foods, 70 849 Cannel coal, 6 705 Cannizzaro reaction, 72 110 solid-state crossed, 76 574 Cannon-Fenske viscometer, 27 728 Canoe fragrances, 75 360 Canonical ensemble, 7 33 Cans, two- and three-piece, 75 37-38. 

Capillary viscometers that have this design are called Ostwald viscometers. There are many specific designs of Ostwald viscometers. The most frequently used are the Cannon-Fenske viscometer... 

The Cannon-Fenske viscometer is used for measuring the kinematic viscosity of transparent Newtonian liquids, especially petroleum products and lubricants. The Ubbelohde viscometer is also used for the measurement of kinematic viscosity of transparent Newtonian liquids, but by the suspended level principle. 

Is a Cannon-Fenske viscometer a capillary type or a rotational type Explain. 

Distinguish between a Cannon-Fenske viscometer and a Ubbelohde viscometer. 

A Cannon-Fenske viscometer is a capillary type of viscometer. It utilizes the flow through a capillary tube as a means of measuring viscosity. 

Solution Viscosity Studies. Ths polymer solution viscosity was run on two modified polymers and the original poly(vinyl alcohol) at 30°C in DMSO solutions using a series 100 Cannon-Fenske viscometer. The observed specific viscosities and the intrinsic viscosity for each of these samples are summarized in Table III. 

Batch flow times are generally used in other words, the time required for a fixed amount of sample to flow from a reservoir through a capillary is the datum actually observed. Any features of technique that contribute to longer flow times are usually desirable. Some of the principal capillary viscometers in use are those of Cannon-Fenske, Ubbelohde, Fitzsimmons, and Zeitfuchs. 

Viscometers Devices for measuring viscosity are called viscometers. The most common viscometer consists of a Cannon-Fenske tube, which is a U-shaped glass tube (see Figure 5.6), one arm of which consists of a capillary tube through which liquids flow slowly. The more viscous the liquid, the longer it takes for a given volume to flow through the capillary. This time is related to the viscosity of the liquid in poise or centipoise, which can be calculated from the measured time, a calibration constant, and the liquid s... 

Figure 5.6 Cannon-Fenske viscometer. (Courtesy of Wilmad/LabGlass.)... 

Cannon-Fenske Ubbelohde FitzSimons SILC Atlantic Zeitfuchs... 

The Ubbelohde viscometer is shown in Figure 24c. It is particularly useful for measurements at several different concentrations, as flow times are not a function of volume, and therefore dilutions can be made in the viscometer. Modifications include the Cannon-Ubbelohde, semimicro, and dilution viscometers. The Ubbelohde viscometer is also called a suspended-level viscometer because the liquid emerging from the lower end of the capillary flows down only the walls of the reservoir directly below it. Therefore, the lower liquid level always coincides with the lower end of the capillary, and the volume initially added to the instrument need not be precisely measured. This also eliminates the temperature correction for glass expansion necessary for Cannon-Fenske viscometers. 

Fig. 17.1 Two types of viscometers Ubbelohde (left) and Cannon-Fenske (right). The Ubbelodhe viscometer has the following components (1) fill tube, (2) capillary outlet, (3) pressure relief tube, (4) solution bulb, (5) suspended volume bulb, (6) lower flow bulb, (7) upper flow bulb, (8) upper timing mark, and (9) lower timing mark. The Cannon-Fenske Viscometer has the following components (1) fill tube, (2) capillary outlet tube, (3) solution bulb, (4) lower flow bulb, (5) upper flow bulb, (6) upper timing mark, and (7) lower timing mark.

Viscometry. Viscosities of aqueous polymer solutions were measured using a Cannon-Fenske 50 viscometer immersed in a 20°C water bath. The limiting viscosity number was determined from 5 viscosity measurements using the Huggins equation (9). The limiting viscosity number of aged poly( 1-amidoethylene) in 0.01 M aqueous Na2SC>4 was 2.45 dL/g. 

This unit describes a method for measuring the viscosity (r ) of Newtonian fluids. For a Newtonian fluid, viscosity is a constant at a given temperature and pressure, as defined in unit hi. i common liquids under ordinary circumstances behave in this way. Examples include pure fluids and solutions. Liquids which have suspended matter of sufficient size and concentration may deviate from Newtonian behavior. Examples of liquids exhibiting non-Newtonian behavior (unit hi. i) include polymer suspensions, emulsions, and fruit juices. Glass capillary viscometers are useful for the measurement of fluids, with the appropriate choice of capillary dimensions, for Newtonian fluids of viscosity up to 10 Pascals (Newtons m/sec 2) or 100 Poise (dynes cm/sec 2). Traditionally, these viscometers have been used in the oil industry. However, they have been adapted for use in the food industry and are commonly used for molecular weight prediction of food polymers in very dilute solutions (Daubert and Foegeding, 1998). There are three common types of capillary viscometers including Ubelohde, Ostwald, and Cannon-Fenske. These viscometers are often referred to as U-tube viscometers because they resemble the letter U (see Fig. HI.3.1). 

This protocol describes a method for measuring the viscosity of pure liquids and solutions by capillary viscometry. The sample is loaded into a Cannon-Fenske viscometer. The time required for the sample to flow between two time points on the viscometer is used to calculate the kinematic viscosity or viscosity. 

Clean the Cannon-Fenske viscometer by placing the appropriate solvent into a solvent wash bottle. Continuously flush and aspirate the solvent through the viscometer until it is clean. 

Table H1.3.1 ASTM" Sizes, Viscosity Ranges, and Constants for Cannon-Fenske Type Viscometer Tubes... 

This method is an adaptation of the Basic Protocol for measuring the viscosity of pure liquids and solutions. The °brix (unithi.4) of the sample is adjusted to a desired value by dilution. In many protocols, a nominal value of 5 °brix is the accepted target value for dilution. The sample is then filtered to remove particles that would plug the capillary tube of the viscometer, and the serum viscosity is measured in a Cannon-Fenske viscometer. 

Fig. 6.37. Common capillary viscometers (a) simple Ostwald type (b) Cannon-Fenske type...

Many modifications of the basic Ostwald geometry are employed in different situations. One example is the Cannon-Fenske routine viscometer (Fig. 6.37b) which is used in the oil industry for measuring kinematic viscosities of 0.02 m2/s and less(4<). As viscosity is sensitive to variations in temperature, these types of viscometer are always immersed in a constant temperature bath. They are not normally suitable for non-Newtonian fluids although FAROOQI and Richardson(47) have employed a capillary viscometer to characterise a power-law fluid. 

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