Theory of Operation

The motive steam accelerates to such a great velocity that it can exceed the speed of sound (that is, exceed sonic velocity). This tremendous increase in velocity of the steam represents a tremendous increase in the kinetic energy of the steam. The source of this kinetic energy is the pressure of the steam. 

Similarly, as the high-velocity steam enters the mixing chamber shown in Fig. 16.1, it produces an extremely low pressure. The gas flows from the jet suction nozzle and into the low-pressure mixing chamber. It is not correct to say that the gas is entrained by the steam. The gas just flows into the mixing chamber, because there is a very low pressure in the mixing chamber. 

The rest of the jet is used to boost the gas from the mixing chamber, up to the higher pressure in the condenser. This is done in two compression steps converging and diverging. 

The converging-diverging steam jet is a startlingly complex device. Not only is the theory of operation rather weird, but the jets are subject to a wide range of odd, poorly understood, and never reported malfunctions. For all these reasons, I dearly love to retrofit and troubleshoot steam jet systems. 

Steam jets have been around for a long time. They have just as ancient an origin as do steam-driven reciprocating pumps. They were used on early steam engines to pull a vacuum on the now-archaic barometric condenser. More recently, they were used to develop vacuums in such services as 

Steam jets are also employed to recompress low-pressure steam to a higher-pressure steam. Jets are sometimes used to compress low-pressure hydrocarbon vapors with higher-pressure hydrocarbon gas (instead of steam). They are really wonderful and versatile machines. 

The conversion of pressure to velocity is a rather common, everyday phenomenon. Remember Hurricane Opal, which struck the Florida Panhandle in October 1995 It had peak winds of 145 miles per hour. The pressure in the eye of the hurricane was reported at 27 inches Hg. A portion of the kinetic energy of the wind in a hurricane is derived from the barometric pressure of the atmosphere. The lift that helps an airplane fly is also a result of the conversion of barometric pressure to velocity. Because of the shape of the wing, the air passes across the top of the wing at a higher speed than it 

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Theory of operation 1/27 Li.st of formulae used 1/34 Further reading 1/34... 

The theory of operation of such a protection scheme is based on the prineiple that in a balanced cireuit the phasor sum of currents in the three healthy phases is zero, as illustrated in Figure 21.7, and the current through the grounded neutral is zero. In the event of a ground fault, i.e. when one of the phases becomes grounded, this balance is upset and the out-of-balance current flows through the grounded neutral. A healthy three-phase circuit, how ever. 

This method is applicable to single-star or delta-connected capacitor banks. Unbalance can be detected through the use of an RVT (residual voltage transformer) (Section 15.4.3). See Figure 26.4. The theory of operation is that any unbalance, of the system or the capacitor bank, will shift the neutral and reflect as the residual voltage across the open delta and can be used for the protective scheme. The unbalance voltage across the open delta in the event of failure of a unit in any series group can be expressed by... 

Introduction DG set Operating parameters Theory of operation Guidelines on the selection of a DG set Types of loads Starting of a DG set Proteetion of a DG set Parallel operation Procedure of parallel operation Recommended protection for a synchronizing scheme Load sharing by two or more generators Total automation through PLCs... 

Thermal Recuperative Oxidizer - The best way to understand the theory of operation for thermal recuperative oxidation is by the three "Ts" of combustion ... 

The theory of operation for the SSD system is that by penetrating the concrete floor slab with an exhaust pipe one gains access to the area beneath the slab. The area, often a gravel bed, serves as a... 

FIGURE 31.12 Theory of operation of a SSD system. (Adapted from U.S. EPA, Radon-Resistant Construction Techniques for New Residential Construction—Technical Guidance, EPA/625/2-91/032, U.S. Environmental Protection Agency, Washington, DC, February 1991.)... 

Figure 31.12 shows the theory of operation, a simple system layout, and the components of an SSD system. 

The separators in Figure 2.3 may be either a cyclone type, as typified by the Bradley microsizer or a mechanical air separator. Cyclone separators, the theory of operation and application of which are fully discussed in Chapter 1, may be used. Alternatively, a whizzer type of air separator such as the NEI air separator shown in Figures 1.29 and 1.30 is often included as an integral part of the mill, as shown in the examples of the NEI pendulum mill in Figure 2.21. Oversize particles drop down the inner case and are returned directly to the mill, whilst the fine material is removed as a separate product stream. 

After optimization of the correct capillary parameters (ID, OD, Lj), detection at the microscale level became the next major challenge for the survival of CE. Despite the challenges, many of the common HPLC detectors have a CE complement, e.g., absorbance, fluorescence, conductivity, photodiode array, and mass spectroscopy. Small dimensions mean universal detectors such as refractive index cannot be used. A sample of detectors will be discussed. The technical aspects of each detector will not be covered except in relation to the CE instrument. Readers are advised to consult an instrumentation textbook for more details on theory of operation. 

The theory of operation of each circuit is discussed, followed by the circuit schematic, the simulation results, and a comparison to laboratory data. Advantages and disadvantages of each circuit are added, along with any tips or hints useful in modeling the circuit accurately. We have attempted to perform each simulation using several versions of SPICE for comparison. Also included are the run times for each circuit simulation. 

The theory of operation of a demister is simple. Vapors and droplets of liquid strike the demister with a substantial velocity. The force of... 

MASER. An acronym for microwave amplification by stimulated emission of radiation. The device is identical in theory of operation to the laser except that it operates at frequencies in Ihe microwave region of the electromagnetic spectrum, rather than in the light range. See also Lasers. 

Our discussion up to now has concerned the cooling of hot process waters exclusively. However, we insisted back in Chapter 1 that a cooling tower is nothing more than a device that transfers heat from one mass to another. Therefore, gas coolers are governed by the same theory of operation and design principles as are water cooling towers. 

The theory of operation of the conductometric gas membrane sensor has been experimentally verified in detail for CO2 and SO2, and sensors for H2S and NH3 based on the same principle have also been made. The basic transport and equilibration processes are the same as in the Severinghaus electrode (Section 6.2.2). Upon entering the aqueous solution inside the cell, the gas dissociates to its constituent ions. Because each dissociated species contributes to the overall conductivity, the specific conductance A of the cell is... 

Instrument manufacturers all have detailed Web sites containing considerable information, not only on their equipment but on theory of operations, methods to maximize sensitivity, etc. The following are some government Web sites that can be searched for analytical methods http //www.epa.gov/pesticides/ (A number of links to US EPA analytical methods) http //www.nal.usda.gov/ http //npic. orst.edu/... 

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