Analysis of the jet pump for generating vacuum important applications (a)

Jet pumps are widely used to transport, compress gas mixtures and steam, liquid and solid equipment, gas or liquid is often used as a power medium. Jet pumps for vacuum generation are another very important application. The main principle of the jet pump is that the jet nozzle drives and accelerates the surrounding liquid, gas or solid with the liquid or gas ejected at a high speed. This movement leads to a mixture of drive and driven material. Jet speed decreases at diffuser and pressure increases. Unlike traditional pumps, jet pumps have no moving parts when working. Jet pumps can be made from a wide variety of materials such as cast iron, steel, stainless steel, Hastelloy, titanium, enamel, glass, plastic and graphite, and can be made in a variety of sizes. Suction from 1 ~ 2000000m3 / h, suction pressure to 10-2mbar, the size can be from a few centimeters to 30 meters. Due to the diversity of jet pumps, it has been widely used in various fields such as chemical reactors, exhaust systems, water treatment equipment, mixing tanks, storage tanks, waste water treatment equipment, heating systems, heating air systems, power plants, Swimming pool, salmon factory water supply. As well as the vacuum in different industrial fields. The use of water vapor as a motive medium jet pump to form a vacuum is an important application area. The delivery of high-speed jet equivalent to several times the speed of sound, jet pump can also be easily handled in a vacuum bulk material. Because single-stage jet pumps can only overcome extremely limited compression ratios, several jet pumps must be installed in series when the suction pressure is low. Multistage steam injection vacuum pump suction pressure can be as low as 0.01mbar. In order to condense most of the motive steam and to minimize the suction at the next stage, a condenser is usually placed between the two jets. Depending on the application, a direct contact condenser or surface condenser is used. In the jet pump water vapor as the main medium. In most industries, water vapor is largely produced as basic energy and is therefore very readily available. In the condensation of motive steam, wastewater is more or less generated. Although the volume is small, and even taking wastewater discharge costs into account, steam jet pumps are still the most economical vacuum pumps, but there is always a negative impact on vacuum jet pumps. As a result, product steam is increasingly being used for jet pump operation. For example, solvent vapor, chlorobenzene, toluene, butanediol, ethylene, ethylene glycol, furan. In this case, the re-evaporation of the motive steam after condensation is used as the motive medium. Due to the low evaporation temperature of organic vapor, in most cases, this mode of operation is more energy efficient than using steam.