Truncated cone and plate

G. Truncated Cone-and-Plate Instrument R = Radius of circular plate Rq Radius of truncated section of cone... 

To overcome the problem of shear field inhomogeneity a small angle (truncated) cone and plate geometry has been used by Janeschitz-Kriegl and co-workers. The stress-optic relation was found to be true for polymer melts in both transient and steady shear conditions up to shear stresses of the order of Pa (some deviation occurred in the transient measurement and was attributed to... 

The slit is a useful characterization device, as C found by Mackay agrees within 5-10% of the values given by Wales obtained in a truncated cone and plate for similar melts. 

The apex of a cone is brought into close proximity, but not in to contact, of a horizontal plate (Figure 3-7). Often, the apex is truncated slightly to eliminate a sharp point. The minimum gap between the cone and plate is usually of the order of 50 xm so that this geometry may not be suitable for dispersions containing larger diameter solids. The test fluid fills the gap between the cone and the plate, and because the gap is small, only a small volume (typically, 1-5 mL) of fluid is needed. The cone is rotated and the torque is measured at various speeds of rotation. A cone and plate viscometer can be used to obtain shear stress-shear rate curves and shear-stress versus time at constant shear rate curves as described above for concentric cylinder geometry. The... 

The Annular Cone and Plate. The concept of the annular cone is thought to be new. Figure 3 shows a comparison of truncated and annular cones. With the truncated cone there is a small error associated with the torque developed over the flat surface, and for this reason the truncation is kept small. In turn, this imposes... 

Aud.nopropyl triethoxysilane, 140 Amorphous systems, polyurethane elastomers, 33 Anionic polymerization, caprolactams, 136-38 initiation, 138 thermal initiation, 137f termination reaction, 136 Annular cone and plate, 100-102 Annular vs. truncated cones, 101f Aromatic diisocyanate(s), RIM elastomers, 81... 

An instrument employed in the test method is either a cone-and-plate rheometer or a parallel-plate rheometer. In the first case, a flat, circular plate and a linearly concentric cone are rotated relative to each other. The cone is normally truncated so that there is no physical contact between the two. The fluid is in the space between the plate and cone. Either of the two members can be rotated or oscillated, and one measures the torque needed to keep the other member stationary. For both Newtonian... 

Parallel-plate rheometers are often more useful for studying rheology of filled polymers or composite materials, particularly when the size of the fillers is comparable fo fhe disfance between the truncated cone and the surface of the plate. Again, the torque M and the normal force N tending to separate the two plates are measured. In steady-shear flow, the shear rate and the shear stress at the edge of the disks located atr = R are given by... 

In the cone-and-plate geometry, the test sample is contained between an upper rotating cone and a stationary flat plate (see Figiue 2.5, upper). In the example shown, the cone is 40 mm in diameter, with a cone angle of V 59 relative to the plate, and a truncation of 51 pm. 

An unfortunate consequence of the latter is that cone-and-plate sensor systems are not convenient for suspensions and emulsions unless truncated cones are used. Another problem that arises is that large gap sizes or plaie-plaie. separa-tion.s have to be used, which requires more involved calculations of the. shear rate across the gap (see Sec, II.C). 

Suspended particles can lead to two kinds of problem. First, large solid particles can become jammed in narrow parts of certain geometries, such as the cone and plate. However, the cone truncation often used to prevent wear of the tip, often helps. Second, if the viscometer gap is not around five to ten times larger than the largest particles, then the correct viscosity of the material is not being measured, since the particle spatial distribution is being altered by the wall. 

The cone-n-plate viscometer is a widely used instrument for measurement of shear flow rheological properties of polymer melts [9-20]. The principal features of this viscometer are shown schematically in Fig. 3.1. The sanaple, whose rheological properties are to be measured, is trapped between the circular conical disk at the bottom and the circular horizontal plate at the top. The cone is connected to the drive motor which rotates the disk at various constant speeds, whereas the plate is connected to the torque-measuring device in order to evaluate the resistance of the sample to the motion. The cone is truncated at the top. The gap between the cone and plate is adjusted in such a way as to represent the distance that would have been available if the untruncated cone had just touched the plate. The angle of the cone surface is normally very small (0o 4° or 0.0696 radians) so as to maintain [4] cosec Op = 1. The cone angles are chosen such that for any point on the cone surface, the ratio of angular speed and distance to the plate is constant. This ensures that the shear rate is constant from the cone tip to the outer radius of the conical disk. Similarly, the shear... 

Friction properties were measured on disk specimens, 2 mm in thickness and 30 mm in diameter, using a rheometer (AR 2000, TA) with a cone-and-plate fixture (cone angle 1°, truncation height 26 oon). The step flow mode was employed and a nominal step shear... 

In this apparatus the plastic to be analysed is placed between a heated cone and a heated plate. The cone is truncated and is placed above the plate in such a way that the imaginary apex of the cone is in the plane of the plate. The angle between the side of the cone and the plate is small (typically <5°). 

Tee Pots,—The crucibles, or pots, in which the vitreous mixture is melted, require every care to bo token in their preparation. Those used for bottle, crown, and plate-glass Lave the form of a truncated cone, a—Pig. 141—the narrow end being the base. Their depth is usually four feet six inches their dia- S-lia-... 

The conventional top spray method shown in Figure 2 has been used for layering and coaling for decades. It evolved from the fluidized bed dryers commercialized more than 40 years ago. The substrate is placed in the product container, which is typically an unbaffled. inverted, truncated cone with a fine retention screen and an air or gas distribution plate at its base. Perforated plates such as a Conidur or Gill plate may also achieve air distribution and product retention. These types of plates may have directed holes for guiding the airflow horizontally in the product container (for side discharge as an example). Process air is drawn through the distribution plate and into the product. 

Fig. 1.6. Beam directioning during soft-landing the focusing octopole ion guide. The schematics present a 3D view of the newly constructed conical octopole guide. Eight rods shaped as truncated cone (diameter rejuvenates from 3 to 0.5 mm) are arranged in a conical geometry. Two Teflon plates at the ends with four carriage bolts and two metal collars (in the cylindrical part) keep the conical geometry. The ion entrance orifice opens 9 mm in iimer diameter and the exit focuses to around 2-mm spot size [74]...

Top-Blown Basic Oxygen Process. The top-blown basic oxygen process is conducted in a cylindrical furnace somewhat similar to a Bessemer converter. This furnace has a dished bottom without holes and a truncated cone-shaped top section in which the mouth of the vessel is located. The furnace shell is made of steel plates ca 50-mm thick it is lined with refractory 600—1200-mm thick (11). 

In practice, the cone is often truncated by a small amount which avoids contact with the cone tip (which might become worn) and the plate (which might become indented). Figure 15b shows the schematic diagram of a truncated cone-plate geometry. A truncated cone also facilitates tests on suspensions (Barnes et al., 1989). If Ri < 0.2R, the torque is reduced by less than 1%. The total torque is reduced by much less than 1% because the parallel plate section near the axis will contribute to the torque (Whorlow, 1980). 

Truncated Cone Pins. Cylindrical pins were found to be sufficient for aluminum plate up to 12 mm (0.5 in.) thick, but researchers wanted to friction stir weld thicker plates at faster travel speeds. A simple modification of a cylindrical pin is a truncated cone (Ref 14, 35, 81) (Fig. 2.12). Truncated cone pins have lower transverse loads (when compared to a cylindrical pin), and the largest moment load on a truncated cone is at the base of the cone, where it is the strongest. 

The Mark 11 primary containment consists of a steel dome head and either a post-tensioned concrete wall or reinforced concrete wall standing on a base mat of reinforced concrete. The inner surface of the containment is lined with a steel plate that acts as a leak-tight membrane. The dr3rwell, in the form of a frustum of a cone or a truncated cone, is located directly above the suppression pool. The suppression chamber is cylindrical and separated from the dr3rwell by a reinforced concrete slab. The drywell is topped by an elliptical steel dome called a dr3rwell head. The drywell inerted atmosphere is vented into... 

A combination of these geometries is provided by the plate and truncated cone apparatus of Lxxige, which provides the radial gradient of pressure in the outer cone region as well as the pressure at the center of the truncated (parallel plate) area. From these measurements, both primary and secondary normal stress differences can be obtained in principle preliminary work suggests, however, that the accuracy obtainable for [Pg.107]

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