If warmup condition is established, the startup pressure control valve will be released to auto control. The steam jet blower is a steam jet or air jet air pump designed for large capacities at low drafts. Leading manufacturer of eductors and ejectors in chennai, india. Steam ejector design pdf schutte koerting has a century of experience in designing and building efficient jet vacuum ejectors. The definitions of overall ejector efficiency and ejector component efficiencies in literature are. Sep 14, 2016 since 1936 graham corporation has been supporting our customers around the globe with heat exchangers, water heaters, steam surface condensers, steam jet ejectors steam vacuums, refrigeration. The system has also been erroneously called steam injector. Graham corporation ejector troubleshooting youtube. Performance optimization of steam jet ejector using cfd.
Request pdf steam jet air ejector performance evaluation for nuclear plants improper design, operation and maintenance of the steam jet air ejector sjae system result in elevated condenser. The efficiency of the ejector cycle is very sensitive to the ejector efficiency. How an air ejector works in a boiler feed system steam turbines. This create a vacuum in a vessels or chamber to which ejector is connected. Steam jet air ejectors are some of the most reliable vacuum creators, but they require proper tube maintenance and replacement of corroded or eroded tubes in order to function efficiently. This steam jet creates a vacuum which extracts air or gas from the adjoining vessel. The basic operating principle of an ejector is to convert the pressure into speed. Pumps are devices used to move liquids or gases by displacing the materials volume. In the derivation of the formula, the density of the layer of air. The attached figures illustrate the two types of steam jet air ejector sjae systems used in the industry to remove noncondensables and water vapor from main condensers.
It is one of the types of air ejector which is used in the steam like near the condenser to remove the non condensable gases and some vapour entering into main condenser by an air ejector and it is cooled by the main condensate and released in the ejector condenser. As a result the roofs have some unique hatches often erroneously called ice hatches. Specialize in design, manufacturing, testing and supply of portable ejectors, bilge ballast cargo ejectors, liquid jet ejectors, air ejectors, acidalkali dilution ejectors, liquid jet exhausters, venturi scrubbers, tank mixer eductors, steam jet heaters, solid conveying eductors. Steam jet air ejector performance evaluation for nuclear. How to calculate the flowrate of motive fluid in an ejector free download as pdf file. Pdf experimental investigation of steam ejector system. An ejector is essentially a fluidfluid pump that has no pistons, valves, rotors, or other moving parts and works by transfer of momentum from the primary fluid high pressure to the secondary fluid aspirated low pressure. Basic ejector components are the steam chest, nozzle, suction, throat, diffuser and they discharge fig. Retubeco will inspect and repair every component of your steam jet air ejector, detecting erosion, steam impingement, and tube failures. The thermocompressor is a steam jet steam compressor, shown with a diaphragmoperated spindle for control purposes.
A general simulation of an air ejector diffuser system derick thomas daniel university of tennessee knoxville, derick. Free demo programs for a short time are offered to let you see how the ejector program works they are not intended for your design work. We have a z and y stage steam jet air ejector on our 160 mw unit. These power systems have found wide acceptance in modern plants because of the small space requirements, simplicity, reliability, low maintenance and quick starting. Nov 01, 2016 the steam jet air ejector is driven by motive steam.
The steam jet blower normally utilizes highpressure steam as the motive force, but compressed air or gas at 15 venturi jet type media. A variety of air conditioning systems were used by american railroads, and santa fe settled on steam ejector air conditioning for the majority of its cars. The model makes use of the field data collected over 35 years by power 1994 for vapor entrainment and compression ratios of steam jet ejectors. At low loads we have been losing vacuum to the point of putting on the hogger and almost tripping the unit. Steam jet air ejectors air ejectors retubeco ooltewah, tn.
Steam jet blowers utilize the ejector venturi principle to move large volumes of air and other gases against low back pressures. In a jet or ejector, a relatively highpressure gas, like steam or air, expands through a nozzle. Steam jet air ejector for motor ships steam jet air ejector a steam jet ejector may be used to withdraw air and dissolved gases from the condenser. They are simple in operation and rugged in construction, can use a wide range of steam pressures, and will handle wet or dry mixtures of air, gases, or vapors at a nearperfect vacuum. As these gases are entrained in the steam, the mixture travels through the ejector into a venturi. Very often, the motive fluid is steam and the device is called a steam jet ejector. A steam jet air ejector is a kind of pump that pulls a fluid in the form of steam via a vacuum effect. The steam or air converts that pressure or potential energy to velocity or kinetic energy. The two major functions of ejectors are as follows.
How an air ejector works in a boiler feed system the air ejector draws out the air and vapours which are released from the condensing steam in the condenser. In each stage of the steam jet ejector, high pressure steam is expanded in a convergentdivergent nozzle. Venturi effect the vacuum used in steam jet air ejector pumps. Steam jet ejectors are an essential part in refrigeration and air conditioning, desalination, petroleum refining, petrochemical and chemical industries. Venturi air jet, steam ejector, liquid eductor ejector.
In certain low suction pressure applications, a hybrid system consisting of a steam jet air ejector and vacuum pump or a three stage ejector system is used for evacuating the air from the condenser. If the steam pressure is being increased from a region of unstabile operation, the point at which the ejector first becomes stable is called the motive steam pickup pressure. Ejector design software ejector sizing calculation ezejector. To start the air ejector, the auxiliary steam supply isolation valve opens with the startup pressure control valve crack open for the initial line warm up. Steam ejector calculations free download as excel spreadsheet. The steam jet ejector is modeled by the semiempirical model developed by eldessouky 1997. The most comprehensive source of design information for ejectors can be found in a series of engineering sciences data unit esdu data items, nos. The steam jet exhauster or vacuum pump is gas jet gas pump and is the basic stage for all high vacuum equipment. Ejector systems ejectors gea engineering for a better world. The basic principle of jet pumps consists in the liquid or gas jet being emitted by a nozzle at high speed entraining and accelerating the surrounding liquid, gas or solid matter. The steam jet ejector utilizes high pressure steam to compress low pressure vapours or gases.
The steam ejector utilizes high pressure steam to compress low pressure vapors or gases. A general simulation of an air ejector diffuser system. The steam nozzle discharges a highvelocity jet across the suction chamber. At the higher discharge pressure, the ejector will regain its stability once the motive steam. The pickup pressure is a direct function of the discharge pressure. Review on ejector efficiencies in various ejector systems. The compression ratio, cr, is the pressure ratio of the compressed and entrained vapors. Steam jet ejectors are based on the ejectorventuri principle. Note that the term jet pump is used to refer to a liquidliquid ejector. Dec 22, 2016 steam jet ejector are used for air removal on surface condensers. Air ejector theory learn how and air ejector works bright. If the air were not removed from the system it could cause corrosion problems in the boiler.
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