【正文】 壞了泵的葉輪。汽蝕效果示意圖在這個數(shù)字說明。 泡沫崩潰后，沖擊波散發(fā)向崩潰的邊緣。這是我們稱之為“汽蝕”其實就像我們聽到的什么沖擊波。氣泡內(nèi)爆破， 簡而言之，汽蝕機(jī)制是所有有關(guān)泵輸送液體內(nèi)部氣泡的形成，生長和崩潰的過程。但如何才能使汽蝕機(jī)制的知識能真正幫助解決汽蝕問題。了解它的機(jī)Phenomenon of Cavitation 8 制和概念，可以幫助確定氣泡的類型和他們的形成和崩潰的原因。 (5) 解決方案和補救辦法：對于汽化 （蝕） 問題 1. 防止 汽化問題，必須增加吸頭，降低流體的溫度，或減少 NPSH（汽蝕余 量） 必需的。我們應(yīng)看看每個可能性： 1）增加吸頭： 提高水箱中的液位 ?提高通進(jìn) 口的位置 ?放置在一個坑泵 ?減少管道損失。這些損失發(fā)生的各種原因，包括： 。有太多的配件或管道直徑太小一個管道內(nèi)襯已經(jīng)崩潰。 。 ，尤其是 它在重型車輛運行的時候。 過濾網(wǎng)被堵塞。 ，不妨礙。通料 口可以在寒冷的天氣凍結(jié) 。 ， 它要么增長，或留在最后一次打開系統(tǒng)。也許止回閥被打破，東西卡在管內(nèi)。 ， 已經(jīng)出現(xiàn)的腐蝕。 ，現(xiàn)行的制度有太多的損失，增加容量。 ，用來取代閘閥。 。 11. 增加 泵的轉(zhuǎn)速。 2）降低流體的溫度 ?注射少量液體冷卻器往往是不切實際的。 ?絕緣管道想著太陽的一面。 ?小心放電循環(huán)線，他們可以加熱吸收液。 3）降低 必需 . 量 ?使用雙吸泵。這可以減少 .，或在某些情況下，它將使你由 41％提高泵的轉(zhuǎn)速降低達(dá) 27％ ?使用較低速度的離心泵 ?使用具有 較大的葉輪泵。 ?如果可能的話，安裝誘導(dǎo)裝置。這些誘導(dǎo)裝置可以減少 50％。 ?使用幾個較小的泵。三個半容量泵可以比一個大的泵便宜，加上備用。這也將保存較輕負(fù)載的能量。 ： 9 1．減少吸入管道 的碎片。 2． 接近泵源槽 /油底殼 。 3． 增加吸線直徑。 4． 降低吸程要求 。 5． 安裝較大的泵運行速度較慢這將降低泵（ NPSHR 值）所需的汽蝕余量 。 6． 增加的壓力。 7． 全開吸入管路閥門。 ： 1． 改變放電線位置 。 壓頭的要求。 ，它會保持無放電空泡所需流動。 。 ： 。 。 10 CENTRIFUGAL PUMPS IN THE CHEMICAL INDUSTRY Abstract : A centrifugal pump converts the input power to kiic energy in the liquid by accelerating the liquid by a revolving device an impeller. The most mon type is the volute pump. Fluid enters the pump through the eye of the impeller which rotates at high speed. The fluid is accelerated radially outward from the pump chasing. A vacuum is created at the impellers eye that continuously draws more fluid into the pump . This article stresses on a series of centrifugal pumps， From a brief introduction to the principles. Keywords : centrifugal pump ,Introduction ,Working principle , Cavitation ， Mechanism of Cavitation ， Solution and Remedies 1. Introduction Pump ,device used to raise ,transfer ,or press liquids and gases .Four general classes of pumps for liquids are described below .In all of them ,steps are taken to prevent cavitation (the formation of a vacuum) ,which would reduce the flow and damage the structure of the pump .Pumps used for gases and vapors are usually known as pressors .The study of fluids in motion is called fluid dynamics. Water pump ,device for moving water from one location to another ,using tubes or other machinery .Water pumps operate under pressures ranging from a fraction of a pound to more than 10,000 pounds per square inch .Everyday examples of water pumps range from small electric pumps that circulate and aerate water in aquariums and fountains to sump pumps that remove water from beneath the foundations of homes . One type of modern pumps used to move water is the centrifugal pump .Early version of the centrifugal pump ,the screw pump ,consists of a corkscrewshaped mechanism in a pipe that ,when rotated ,pulls water upward .Screw pumps are often used in wastewater treatment plants because they can move large amounts of water without being clogged with debris .In the ancient Middle East the need for irrigation of farmland was a strong inducement to develop a water pump .Early pumps in this region were simple devices for lifting buckets of water from a source to a container or a trench .Greek mathematician and inventor Archimedes is thought to have devised the first screw pump in the third century BC .Later Greek inventor Ctesibius develop the first lift pump .During the late 17th and early 18th Centuries AD ,British engineer Thomas Savery ,French physicist Denis Papin ,And British blacksmith and inventor Thomas Newen contributed to the development of a water pump that used steam to power the pump’ piston .The steampowered water pump’s first wide use was in pumping water out of mines .Modernday examples of centrifugal pumps are those used at the Grand Coulee Dam 11 on the Columbia River .This pump system has the potential to irrigate over one million acres of land . Also known as rotary pumps ,centrifugal pumps have a rotating impeller ,also known as a blade ,that is immersed in the liquid .Liquid enters the pump near the axis of the impeller ,and the rotating impeller sweeps the liquid out toward the ends of the impeller blades at high pressure .The impeller also gives the liquid a relatively high velocity that can be converted into pressure in a stationary part of the pump ,known as the diffuser .In highpressure pumps ,a number of impeller may be used in series ,and the diffusers following each impeller may contain guide vanes to gradually reduce the liquid velocity .For lowerpressure pumps ,the diffuser is generally a spiral passage ,known as a volute ,with its crosssectional area increasing gradually to reduce the velocity efficiently .The impeller must be primed before it can begin operation ,that is ,the impeller must be surrounded by liquid when the pump is started .This can be done by placing a check valve in the suction line ,which holds the liquid in the pump when the impeller is not rotating .If this valve leaks ,the pump may need to be primed by the introduction of liquid from an outside source such as the discharge reservoir .A centrifugal pump generally has a valve in the discharge line to control the flow and pressure .For low flows and high pressures ,the action of the impeller is largely radial .For higher flows and lower discharge pressure ,the direction of the flow within the pump is more nearly parallel to the axis of the shaft ,and the pump is said to have an axial flow .The impeller in this case acts as a propeller .The transition from one set of floe conditions to the other is gradual ,and for intermediate condition , the device is called a mixedflow pump . Centrifugal Pump The centrifugal pump is by far the most widely used type in the chemical and petroleum industries .It will