An important application of the jet pump in creating a vacuum is analyzed

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. Another important operating area for jet pumps that use product steam as a motive medium is the inability to mix water in process materials. In order to obtain the best efficiency, the use of product steam as a motive medium jet pump still need to study in detail. In terms of structure and function, this jet pump is not significantly different from a vacuum jet pump that uses water vapor as a motive medium, and has the same advantages: simple structure, safe and reliable operation, no maintenance, long service life, wear resistance Loss; Proper selection of materials with corrosion resistance; all materials can be manufactured. In addition, due to the condensate recycling, no emissions pollution. Jet vacuum pump used in a variety of industrial areas, the following are several important areas of application. In the chemical industry GEA jet pump company has developed a combination of pumps, and has been widely used. Notable features of this pump are the compact design and dual design. The two parallel pumps can be operated alternately and independently at the same time, so that it is possible to carry out repairs without stopping. In the chemical industry, ceramic / graphite vacuum jet pumps can be used to remove corrosive gases and water vapor if stainless steel does not meet the decay resistance requirements. The jet pump is made of ceramic and the surface condenser is made of graphite. Surface condensers consist of a compact condenser. This structure has the advantages of small size, less space and simple assembly on site. In refineries, water vapor vacuum jet pumps are used in combination with liquid ring pumps in the refinery's vacuum distillation column system. The combination of these two pumps keeps very low steam, water and electricity consumption. Due to the large volume of gas that can be delivered (in the range of 104 to 106 m3 / h), GEA Jet Pump's water vapor vacuum jet pumps are ideally suited for this purpose. At the same time, safe and reliable operation, and not prone to failure. Also, the case involving large volume flow is in the vacuum generation of steel degassing. In order to produce a certain quality of steel, some raw steel processing needs to be carried out under vacuum. This vacuum pump must have two roles. First, quickly emptying the operating container, in order to achieve the required pressure. This means that the initial amount of suction in the vacuum jet pump must be large (several thousand kg / h). The second is to maintain a low pressure while removing a large amount of inert gas (approximately equivalent to 0.6mbar, hundreds of kg / h). In addition, vacuum jet pumps are also used for deodorization of edible oils, production of polymers for chemical compounds, desalination of seawater, oil dewatering, conditioning of food, beverages and tobacco, aspiration of spinning baths and many other fields of application.