Spinning discs

Spinning disc A rotating disc onto which a fine jet of water impinges, resulting in fine droplets that add moisture to the air supply. 

Water is injected into the air stream in a fine mist by pumped jets or spinning disc. For practical purposes, the psychrometric plot follows a wet bulb line. The air provides the latent heat of evaporation, resulting in a fall in dry bulb temperature. If water were to be supplied at up to 100°C the humidified condition would be at a correspondingly higher total heat of 420 kJ per kg water supplied. 

A similar method of test was used at the International Nickel Company s Corrosion Laboratory at North Carolina. The specimen discs are mounted on insulated vertical spindles and submerged in sea-water, which is supplied continuously to the tank in which the specimens are immersed. The maximum peripheral speed of the spinning disc is about 760cms , and the characteristic pattern of attack is shown in Fig. 19.3a. Studies of variation of depth of attack with velocity indicate that at low velocities (up to about 450 cm s ) alloys such as Admiralty brass, Cu-lONi and cupro-nickel alloys containing iron maintain their protective film with a consequent small and similar depth of attack for the diflferent alloys. At higher velocities the rate increases due to breakdown of the film. 

Ramshaw, C. (2004) The spinning disc reactor, in Re-Engineering the Chemical Processing Plant Process Intensification (eds A. Stankiewicz and J.A. Moulijn), Marcel Dekker Inc., New York, pp. 69-119. 

Boodhoo, K.V.K., Jachuck, R.J., and Ramshaw, C. (1997) Spinning disc reactor for the intensification of styrene polymerization, in Process Intensification in Practice Applications and Opportunities (ed. J. Semel) Mechanical Engineering Publications, Ltd, Bury St. Edmunds, pp. 125-133. 

Spinning disc reactor Supercritical fluids Static mixer reactor Reactor... 

The droplet size delivered from a spinning disc monodisperse aerosol generator can be derived from the following expressions ... 

A simple example is the rotating disc electrode described in detail in chapter 2. The horizontal spinning disc draws liquid up and then flings it out sideways, creating a continuous but steady-state convection pattern. If the distance down from the disc is denoted by z and the distance across the disc surface by the radial distance, r, then it is not difficult to show that ... 

The universal interferometric response of a balanced two-port interferometer is shown in Fig. 11.2 as a function of the fixed phase offset between the two waves. The maximum slope of the intensity curve occurs when the fixed phase offset between the waves is an odd integer of = re/2. These conditions of maximum slope are called the conditions of phase quadrature. There are two quadrature conditions per cycle, with opposite slopes and hence opposite signed responses to modulated phase. These are the positions of maximum phase-to-intensity transduction and are the operating points for interferometric detection of protein or DNA on spinning discs. 

Phase quadrature is an over-arching concept for all interferometric detection. However, achieving a common-path configuration that locks in a stable quadrature condition puts constraints on possible system designs. This section reviews the several configurations of common-path quadrature that have been demonstrated so far in spinning-disc systems. These are the micro-diffraction class, the adaptive optical class, the phase contrast and the in-line class. At the end of this section, we show that the phase-contrast and in-line classes are conjugate quadratures of each other. 

The use of a rotating reactor to provide efficient mixing has been proposed and tested for viscous polymerizations and acid-catalysed rearrangement reactions [6], The principle of these spinning disc reactors is that the centrifugal force... 

Figure 11.5 Schematic diagram of a spinning disc reactor. Products are collected from a cooled trough positioned below the disc...

Impact nozzles Spinning discs Internal mixing... 

Spinning discs are very suitable for slurries and pastes, while high viscosity liquids tend to produce a stringy product. Care must also be taken in design to minimise incrustation around the lip and subsequent out-of-balance as drying takes place. 

Walton, W. H. and Prewett, W. C. Proc. Phys. Soc. 628 (1949) 341. The production of sprays and mists of uniform drop size by means of spinning disc type sprayers. 

It is the aim of this section to offer but a brief introduction to this relatively new field of endeavour that will surely have a not inconsiderable role in shaping the whole future of both physical and chemical processing. It may be noted at the outset, however, that it is not the use of centrifugal forces which is a relatively new development, but rather their application in spinning discs and indeed, centrifugal devices are already widely used in processing, as indicated by the following examples ... 

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