Ejector systems Applications

Dusts, particle sizes, 225 Dusts, hazard class, 521-523 Explosion characteristics, 524 Efficiency, centrifugal pumps, 200 Ejector control, 380 Ejector systems, 343, 344, 351 Air inleakage, table, 366, 367 Applications, 345 Calculations, 359-366 Chilled water refrigeration, 350 Comparison guide, 357, 375 Evacuation lime, 380, 381 Charts, 382 Example, 381 Features, 345... 

Uses of Ejectors For the operating range of steam-jet ejectors in vacuum applications, see the subsection Vacuum Systems. ... 

A reverse philosophy in sizing ejectors is occasionally applicable to a system in which even a small quantity of air leakage will upset the operation or contaminate the product. In such a system it may be desirable to install an ejector having a deliberately limited air handling capacity, so that the system cannot be operated until an injurious rate of air leakage is corrected. 

Vacuum capacities and operating ranges, table, 344, 355 Ejectors, 344, 357 Integrated systems, 344 Liquid ring pumps, 344 Rotary lobe blowers, 344 Rotary piston pumps, 344 Rotary vane pumps, 344 Vacuum equipment, 343 Applications diagram, 352 ASME Code, 344 Pumps, 382 Steam jets, 357 Vacuum flow,... 

Ejector (steam-jet) refrigeration systems are used for similar applications, when chilled water-outlet temperature is relatively high, when relatively cool condensing water and cheap steam at 7 bar are available, and for similar high duties (0.3-5 MW). Even though these systems usually have low first and maintenance costs, there are not many steam-jet systems running. 

As a final precaution, any dirt created by the action of the ejector blast on the particles, may be drawn away from the window area by a dust extraction nozzle, positioned just below the optical box. Similarly, for wet or frozen product applications water jets and wiper blades can be substituted for air-based systems. Machines for sorting wet product are periodically hosed down with water, so must be water and dust proof to IP65 standards. Similarly, dry product machines are also manually cleaned with an air hose. For hygiene reasons, all potential bug traps must be designed out of all sorting machinery. 

A cross-sectional view of the radiant tube and recuperator combination, shown in Figure 21.8, is an example of the application of preheated air combustion system. A recuperator is installed at the exit section of exhaust gases. An air ejector is used to compensate the pressure drop required for passing the exhaust gases through the recuperator prior to the release of exhaust gases to the atmosphere. 

The above optimization problem is applicable to systems involving air and water only. It ignores vapour superheat at the ejector inlet, vapour sub-cooling and liquid sub-cooling in condenser area calculations, and also assumes a simple log-mean temperature driving force (LMTD) without any correction factor. Hence, condenser area calculations are approximate but sufficient for optimization. Actual condenser design is quite complex for systems... 

Thermal compression is the term used to describe the application of a steam jet ejector or thermocompressor to an evaporator in order to increase the steam economy. A typical system is illustrated in Figure 18-1. Steam jet thermocompressors can be used with either single or multiple-effect evaporators. As a rule-of-thumb, the addition of a thermocompressor will provide an improved... 

There is no vacuum source that is the best choice for every application. The technology for protecting mechanical pumps from process upsets and abuse is highly developed. This technology can be used effectively in designed vacuum systems to meet specific requirements. In several applications, mechanical pumps have demonstreted reliability comparable with, or superior to, liquid-ring pumps or steam jet ejectors. 

SOFC systems can be designed to include a heat recovery component such as an adsorption chiller heater for CHP applications [72-76]. An example is a small (1-lOkW) methane-fueled residential CHP SOFC system that integrates CGR, AGR, and internal reforming [73]. The system consists of a fuel-cell stack, steam prereformer, various fluid delivery devices (blowers, ejectors, compressor, and water pump), heat exchangers, and catalytic combustor and power conditioning device along with a heat recovery component. Based on certain system parameters (50active area, nominal cell temperature of 800 °G, current density of 0.57 A cm , power density of0.40-0.43 Wcm , S/G ratio of 2.0, SOFC... 

The fluid entering at A does not have to be the same as that in pipe C/B/D. The most common use of the ejector is in steam systems, with steam being the fluid passing through the narrow pipe and jet A. So, ejectors are used to pump air, for example, to maintain vacuum in the condensers of steam turbines. They are also used to pump water into boilers, and since the steam mixes with the pumped water it also preheats it. The steam is also used to circulate lower pressure steam in steam heating systems. In this application it is closest to its normal use in fuel cell systems. 

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