Pneumatic Principles

The Easi-Breathe is a breath-actuated metered-dose aerosol inhaler developed by Norton Healthcare. The device is primed when the mouthpiece is opened. When the patient breathes in, the mechanism is triggered and a dose is automatically released into the airstream. The inhaler works on a pneumatic principle. An internal vacuum restrains an operating spring. A valve that is operated in response to the patient s inhalation that allows the spring to fire the canister releases the vacuum. It can be actuated at a very low flow of approximately 20 L/min (72). Not surprisingly the device scored better than a pMDI on a number of features, including ease of use and having an attached mouthpiece cover. Practice nurses found it easier to teach and patients easier to learn to use than a conventional pMDI (73). 

A time delay switch based on pneumatic principles whereby a small air space is put under compression and the escape of the air at variable rates terminates in a mechanical action is the subject of another U.S. patent. ... 

Boyle s Law Boyle s law states For a fixed amount of gas kept at a fixed temperature, pressure and volume are inversely proportional. Boyle s law only applies to gases or pneumatics. This pneumatic principle was published by Robert Boyle in 1662 (Figure 11-5). Mathematically, we express Boyle s law as X X P. ... 

As is also the case in atomic absorption spectrometry, the sample must enter the burner via an atomizer in ICP as well. The efficiency of the atomizer plays a considerable role in producing as finely distributed an aerosol as possible. For example, the Meinhardt atomizer, a concentric pneumatic glass atomizer with fixed capillaries, is often used. The quantity of carrier gas and the efficiency of the atomizer have in the meantime been well matched for ICP analysis. The cross-flow atomizer similarly works on pneumatic principles. The two capillaries used are adjustable and can be... 

Nebulizers can be divided into several main types. The pneumatic forms work on the principle of breaking up a stream of liquid into droplets by mechanical means the liquid stream is forced through a fine nozzle and breaks up into droplets. There may be a concentric stream of gas to aid the formation of small droplets. The liquid stream can be directed from a fine nozzle at a solid target so that, on impact, the narrow diameter stream of liquid is broken into many tiny droplets. There are variants on this approach, described in the chapter devoted to nebulizers (Chapter 19). 

The basic principles and approaches to manufacturing pneumatic tires have been in place for many years, and because of the scale of modem tire production, radical change is slow. However, developments of new tire production processes continue (44,45) and as new methods take hold, it is likely that changes in tire cord handling and preparation will be required. 

R. L. Brown and J. C. Richards, Principles of PowderMechanics, Pergamon Press, Oxford, 1970 D. Mills, Pneumatic Conveying Design Guide, Buttersworth, Boston, 1990. 

Additional information on mass-flowmeter principles can be obtained from Yeaple (Hydraulic and Pneumatic Power and Control, McGraw-HiU, New York, 1966, pp. 125-128), Halsell [In.strum. Soc. Am. J., 7, 49-62 (June I960)], and Flanagan aud Colmau [Control, 7, 242-245 (1963)]. Information on commercially available mass flowmeters is given in the latter two references. 

Transport Transport units can be scaled up on the principles of pneumatic conveying. Mass and heat transfer can be predicted on both the shp velocity during acceleration and the shp velocity at full acceleration. The slip velocity is increased as the sohds concentration is increased. 

The blow-tank principle can be used to feed regular pneumatic conveyors. Use of an Airslide or other fluidizing device at the bottom of the blow tank permits handhug non-free-flowing materials. This... 

Basic principles of pneumatic conveying and equations are presented. A new pressure loss equation is presented with examples. 

In principle, the velocities c and ti can be determined by taking a series of pictures at a very high frequency of the flow through a transparent plastic tube. Because of the particle size distribution, each particle moves at a different velocity, and this makes this method difficult to apply in practice. We have therefore used an indirect method, where we have measured the pressure losses of pneumatic conveying for two mixture ratios and then fit the parameters so that Eq, (14.126) coincides as accurately as possible with measured pressure losses. 

In this chapter the pressure drop for pneumatic conveying pipe flow is studied. The conventional calculation method is based on the use of an additional pressure loss coefficient of the solid particles. The advantage of this classical method is that in principle it can be applied to any type of pneumatic flow. On the other hand, its great disadvantage is that the additional pressure loss coefficient is a complicated function of the density and the velocity of the conveying gas. z lso, it is difficult to illustrate the additional pressure loss coefficient and this makes the theoretical study of it troublesome. 

Pneumatic dryers, also called flash dryers, are similar in their operating principle to spray dryers. The product to be dried is dispersed into an upward-flowing stream of hot gas by a suitable feeder. The equipment acts as a pneumatic conveyor and dryer. Contact times are short, and this limits the size of particle that can be dried. Pneumatic dryers are suitable for materials that are too fine to be dried in a fluidised bed dryer but which are heat sensitive and must be dried rapidly. The thermal efficiency of this type is generally low. 

The operating principle of the pneumatic amplifier pump is shown in Fig. 2.2b. 

The principles of operation of a hydraulic actuator are like those of the pneumatic actuator. Each uses some motive force to overcome spring force to move the valve. Also, hydraulic actuators can be designed to fail-open or fail-closed to provide a fail-safe feature. 

Long-Stroke Sensor for Hydraulics and Pneumatics eddy current principle Micro-Epsilon strokeSENSOR... 

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