雙吸離心油泵的結(jié)構(gòu)及其機(jī)械密封的設(shè)計(jì)

1、畢業(yè)設(shè)計(jì)（論文）說(shuō)明書(shū)目錄第一章 引言11.1 離心泵的發(fā)展前景11.2 各種離心泵的的工作環(huán)境1第二章 泵的結(jié)構(gòu)設(shè)計(jì)32.1估算泵的效率32.2軸功率和原動(dòng)機(jī)功率42.3 泵汽蝕余量的計(jì)算方法42.4 泵的基本參數(shù)的確定52.4.1確定泵的進(jìn)口直徑52.4.2 確定泵的出口直徑62.4.3泵轉(zhuǎn)速的確定62.5 葉輪結(jié)構(gòu)設(shè)計(jì)及主要尺寸計(jì)算72.5.1葉輪的材料選擇72.5.2 葉輪結(jié)構(gòu)型式的確定82.5.3葉輪輪轂直徑的計(jì)算82.5.4 葉輪進(jìn)口直徑的計(jì)算92.5.5 葉輪外徑的計(jì)算102.5.6 葉輪出口寬度的計(jì)算102.5.7 葉片數(shù)的計(jì)算和選擇112.5.8精算葉輪外徑122.5.9 葉

2、輪進(jìn)口速度122.5.10 葉輪出口速度142.5.11 葉輪強(qiáng)度計(jì)算142.6 軸的設(shè)計(jì)計(jì)算172.6.1 扭矩的計(jì)算172.6.2 根據(jù)扭矩計(jì)算泵軸直徑的計(jì)算182.6.3 畫(huà)出軸的受力簡(jiǎn)圖如圖5.3所示182.6.4 軸的強(qiáng)度計(jì)算182.6.5 軸的彎矩圖212.7 殼體壁厚計(jì)算212.8 壓出室和吸入室的水力設(shè)計(jì)222.8.1 壓出室的水力設(shè)計(jì)222.8.2 渦形體的各斷面面積222.8.3 舌角的計(jì)算242.8.4 渦室進(jìn)口寬度242.8.5 基圓直徑252.9 吸入室的選擇252.9.1 吸入室的作用252.9.2 吸入室的分類25第三章 泵的軸封設(shè)計(jì)計(jì)算263.1 常用的軸封結(jié)構(gòu)

3、及其特點(diǎn)263.1.1常用的軸封結(jié)構(gòu)263.1.2 軸封結(jié)構(gòu)的特點(diǎn)263.2機(jī)械密封的概念組成及其工作原理273.2.1 機(jī)械密封的基本概念：273.2.2機(jī)械密封的組成：273.3 機(jī)械密封的計(jì)算273.3.1端面比壓的計(jì)算和彈簧比壓的選擇273.3.2 機(jī)械密封摩擦功率283.3.3 機(jī)械密封型號(hào)的選擇293.3.4 機(jī)械密封的材料選擇例表3-3.130致謝31參考文獻(xiàn)32英語(yǔ)翻譯33中文翻譯41第一章 引言1.1 離心泵的發(fā)展前景泵在國(guó)內(nèi)是應(yīng)用相當(dāng)廣泛的能用機(jī)械產(chǎn)品，不管是農(nóng)業(yè)機(jī)械，還是工業(yè)機(jī)械，應(yīng)用都很普通。正是因?yàn)楸玫膽?yīng)用范圍很廣，所以中國(guó)每年泵類產(chǎn)品的產(chǎn)值在400億以下，其中全國(guó)發(fā)

4、電量的20%-25%都要消耗在泵類產(chǎn)品上，全國(guó)泵類企業(yè)已達(dá)6000 家以上。 隨著科學(xué)技術(shù)的發(fā)展，人民生活水平的提高，農(nóng)村工業(yè)化，農(nóng)業(yè)生產(chǎn)機(jī)械化越來(lái)越普遍，越來(lái)越多的泵類產(chǎn)品將大批量擁入農(nóng)村市場(chǎng)。隨著泵業(yè)企業(yè)的增多，競(jìng)爭(zhēng)力 越來(lái)越大，將來(lái)泵類產(chǎn)品的高科技技術(shù)，優(yōu)秀的售后服務(wù)將成為最有力的競(jìng)爭(zhēng)手段。做好泵類企業(yè)的廣告宣傳，充分利用可利用的一切資源，特別是網(wǎng)絡(luò)資源，讓更多的用戶了解自己的產(chǎn) 品，讓更多的人有機(jī)會(huì)接觸自己的產(chǎn)品，泵類行業(yè)的前景發(fā)展還是一片光明的。1.2 各種離心泵的的工作環(huán)境 泵是把原動(dòng)機(jī)的機(jī)械能轉(zhuǎn)換成液體能量的機(jī)器。泵用來(lái)增加液體的位能、壓能、動(dòng)能.原動(dòng)機(jī)通過(guò)泵軸帶動(dòng)葉輪旋轉(zhuǎn),對(duì)液

5、體做功,使其能量增加,從而使需要數(shù)量的液體,由吸水池經(jīng)泵的過(guò)流部件輸送到要求的高度或要求壓力的地方。離心泵的主要工作性能參數(shù)有流量Q,揚(yáng)程H,轉(zhuǎn)速 n, 功率P,效率,汽蝕余量等. 泵的結(jié)構(gòu)型式有很多，例如單吸單級(jí)泵，兩極懸臂泵，雙吸單級(jí)泵，分段式多級(jí)泵，渦殼式多級(jí)泵深井泵，潛水電泵等。單吸單級(jí)泵的用途很多一般流量在揚(yáng)程在范圍內(nèi)都用這種泵。軸封機(jī)構(gòu)可以采用機(jī)械密封，也可以采用填料密封和浮動(dòng)密封。兩級(jí)懸臂泵用于單級(jí)懸臂泵不滿足要求，而采用多級(jí)泵的級(jí)數(shù)又較少時(shí)。這種泵的揚(yáng)程范圍為流量為。分段式多吸泵實(shí)際上等于將幾個(gè)葉輪裝在一根軸上，串聯(lián)的工作所以其揚(yáng)程一般較高。它的流量一般在，揚(yáng)程在范圍內(nèi)。采用螺

6、旋形壓出室的泵叫做渦殼式多級(jí)泵。這種泵一般用與流量較大揚(yáng)程較高的城市供水，礦山排水和輸油管線等，這種泵的揚(yáng)程范圍為，流量為如果要把深井的水提到地上來(lái)，一般采用深井泵。其使用電機(jī)一般為立式電機(jī)。其井徑一般在范圍內(nèi)，泵的流量為，揚(yáng)程為。雙吸單級(jí)泵在 工業(yè)和農(nóng)業(yè)各部門使用也較廣，它實(shí)際上是等于將兩個(gè)相同的葉輪背靠背的裝在一根軸上并聯(lián)的工作，這種泵不但流量較大，而且能平衡軸向力，其流量在，揚(yáng)程在范圍內(nèi)。軸封機(jī)構(gòu)可用機(jī)械密封，填料密封等，一般用機(jī)械密封。而且它能提高泵的總效率。 泵在國(guó)內(nèi)是應(yīng)用相當(dāng)廣泛的能用機(jī)械產(chǎn)品，不管是農(nóng)業(yè)機(jī)械，還是工業(yè)機(jī)械，應(yīng)用都很普遍。基本用途主要用來(lái)輸送液體，包括水，油，乳化液

7、，液態(tài)金屬等，也可以輸送液體、氣體混合物。 本課題要采用流量為，揚(yáng)程為， 的主要參數(shù)同時(shí)要使泵有較高的效率，綜和比較各種泵的使用環(huán)境和流量揚(yáng)程范圍選用單級(jí)雙吸式離心泵。 第二章 泵的結(jié)構(gòu)設(shè)計(jì)2.1估算泵的效率1.水力效率 水力效率按下式計(jì)算式中：泵流量（m3/s）雙吸泵取 泵的轉(zhuǎn)速（r/min）2.容積效率 容積效率可按下式計(jì)算該容積效率為只考慮葉輪前密封環(huán)的泄漏的值,對(duì)于有平衡孔、級(jí)間泄漏和平衡盤(pán)泄漏的情況,容積效率還要相應(yīng)降低。則 3.機(jī)械效率泵的總效率 泵的理論揚(yáng)程 泵的理論流量 2.2軸功率和原動(dòng)機(jī)功率泵的軸功率原動(dòng)機(jī)功率式中: 余量系數(shù) 查【現(xiàn)代泵技術(shù)手冊(cè)關(guān)醒凡編著】 表7-10取=

8、1.1(原動(dòng)機(jī)為電動(dòng)機(jī))傳動(dòng)效率 查【現(xiàn)代泵技術(shù)手冊(cè)關(guān)醒凡編著】 表7-11取(直聯(lián))所以選擇45Kw的電動(dòng)機(jī)可滿足要求,查【機(jī)械零件手冊(cè)吳宗澤主編】選擇電動(dòng)機(jī)的型號(hào)為Y225-22.3 泵汽蝕余量的計(jì)算方法汽蝕余量對(duì)于泵的設(shè)計(jì)、試驗(yàn)和使用都是十分重要的汽蝕基本參數(shù)。設(shè)計(jì)泵時(shí)根據(jù)對(duì)汽蝕性能的要求設(shè)計(jì)泵,如果給定了具體的使用條件,則設(shè)計(jì)泵的汽蝕余量必須小于按使用條件確定的裝置汽蝕余量。欲提高泵的汽蝕性能,應(yīng)盡量減小。裝置汽蝕余量又叫有效的汽蝕余量。泵汽蝕余量又叫必需的汽蝕余量,是規(guī)定泵要達(dá)到的。汽蝕余量必需滿足如下關(guān)系:泵汽蝕余量的計(jì)算: 式中: 托馬汽蝕系數(shù)； 泵最高效率點(diǎn)下的泵單級(jí)揚(yáng)程； 最

9、高效率點(diǎn)下的泵汽蝕余量。根據(jù)【現(xiàn)代泵技術(shù)手冊(cè)關(guān)醒凡編著，宇航出版社?！?查圖4-7取=0.035所以2.4 泵的基本參數(shù)的確定2.4.1確定泵的進(jìn)口直徑泵進(jìn)口直徑也叫泵吸入口徑,是指泵吸入法蘭處管的內(nèi)徑.吸入口主要取決于流速。泵的進(jìn)口流速一般為3m/s左右，從制造經(jīng)濟(jì)行考慮，大型泵的流速取大些，以減小泵體積，提高過(guò)流能力。從提高抗汽蝕性能考慮，應(yīng)取較大的進(jìn)口直徑，以減小流速。常用的泵吸入口徑，流量和流速的關(guān)系如圖所示。對(duì)抗汽蝕性能要求高的泵，在吸入口徑小于250mm時(shí)，可取吸入口徑流速，在吸入口徑大于250mm時(shí)，可取。吸入流速按下式確定。 ；流速，流量與吸入口徑的關(guān)系如表2-4.1。吸入口徑

10、（mm）40506580100150200250單級(jí)泵流速（m/s）1.3751.772.12.763.532.832.652.83流量（m3/h）6.2512.52550100180300500表2-4.1注：此表取自【現(xiàn)代泵技術(shù)手冊(cè)關(guān)醒凡編著，宇航出版社?！咳∥肟诹魉?，代入公式得：取泵的吸入口徑為150mm。2.4.2 確定泵的出口直徑 泵出口直徑也叫泵排出口徑，是指泵排出法蘭處管的的內(nèi)徑。對(duì)于低揚(yáng)程泵，排出口徑可與吸入口徑相同；對(duì)于高揚(yáng)程泵，為減小泵的體積和排出管路直徑，可取排出口徑小于吸入口徑，一般取 式中：泵的排出口徑 泵的吸入口徑根據(jù)該泵的特性，由于該泵的流量大，考慮排水管路的經(jīng)

11、濟(jì)性取2.4.3泵轉(zhuǎn)速的確定 一.影響泵轉(zhuǎn)速的因素：1.泵的轉(zhuǎn)速越高，泵的體積越小，重量越輕，據(jù)此應(yīng)選擇盡量高的轉(zhuǎn)速；2.轉(zhuǎn)速和比轉(zhuǎn)數(shù)有關(guān)，而比轉(zhuǎn)數(shù)和效率有關(guān)，所以轉(zhuǎn)速應(yīng)該和比轉(zhuǎn)數(shù)結(jié)合起來(lái)確定；3.泵的轉(zhuǎn)速受到汽蝕條件的限制，從汽蝕比轉(zhuǎn)數(shù)公式 式中： 泵的轉(zhuǎn)速（r/min） 泵流量（m3/s）雙吸泵取可知：轉(zhuǎn)速和汽蝕基本參數(shù)及有確定的關(guān)系，如得不到滿足，將發(fā)生汽蝕。二泵的轉(zhuǎn)速計(jì)算：選 ,，則 根據(jù)汽蝕要求，泵的轉(zhuǎn)速應(yīng)小于，從實(shí)際選定的電機(jī)來(lái)看泵的轉(zhuǎn)速應(yīng)為。故滿足條件。計(jì)算比轉(zhuǎn)數(shù)由此可知這樣的比轉(zhuǎn)速不能達(dá)到預(yù)定的要求修正得由故設(shè)計(jì)成雙吸泵。2.5 葉輪結(jié)構(gòu)設(shè)計(jì)及主要尺寸計(jì)算2.5.1葉輪的材料選

12、擇葉輪是離心泵傳遞能量的主要部件，通過(guò)它把電能轉(zhuǎn)換為液體的壓力能和動(dòng)能，因此，要求葉輪具有足夠的機(jī)械強(qiáng)度和完好的葉片形狀，在材料上，除了考慮介質(zhì)腐蝕，磨損外，由于它是旋轉(zhuǎn)部件，故還應(yīng)考慮離心力作用下的強(qiáng)度。通常，用于葉輪的材料有鑄鐵，青銅鑄件，不銹鋼，鉻鋼等。當(dāng)葉輪圓周速度超過(guò)30m/s，考慮鑄鐵強(qiáng)度不能承受這樣大的離心力的作用，則需改用青銅作材料，由于本設(shè)計(jì)泵屬于中小型泵，其圓周速度遠(yuǎn)小于30m/s，在考慮到材料來(lái)源的難易，鑄造上的方便與否，同時(shí)考慮到泵的效率和抗汽蝕性能的要求，故選灰口鑄鐵，雖然它的強(qiáng)度不高，但它的生產(chǎn)工藝簡(jiǎn)單，價(jià)格低廉，易于熔化，澆鑄性能好，冷凝的收縮性小，而且，其切削性

13、能好，便于加工，減振性好，可以減輕由于水力沖擊造成的振動(dòng)，而HT200又是在灰口鑄鐵中這些性能更為突出的，所以，本設(shè)計(jì)中葉輪的材料選用HT200作為原材料，熱處理采用退火，許用應(yīng)力為&25-35MPa2.5.2 葉輪結(jié)構(gòu)型式的確定葉輪一般可分為單吸式和雙吸式兩種。單吸式葉輪為單邊吸水葉輪前蓋板不對(duì)稱，雙吸式葉輪為雙邊吸水前蓋板對(duì)稱。一般大流量離心泵多采用雙吸式葉輪。葉輪按形狀可分為畢式，開(kāi)式，半畢式。本設(shè)計(jì)選用閉式葉輪。閉式葉輪由前蓋板，后蓋板，葉片和輪轂組成。葉輪主要尺寸的確定有三種方法：相似換算法、速度系數(shù)法、葉輪外徑或葉片出口角的理論計(jì)算。此處葉輪的計(jì)算采用速度系數(shù)法設(shè)計(jì)，速度系

14、數(shù)法是建立在一系列相似泵基礎(chǔ)上的設(shè)計(jì)，利用統(tǒng)計(jì)系數(shù)計(jì)算過(guò)流部件的個(gè)部分尺寸。2.5.3葉輪輪轂直徑的計(jì)算 葉輪示意圖2-4.3葉輪輪轂直徑必須保證軸孔在開(kāi)鍵槽之后有一定的厚度，使輪轂具有足夠的強(qiáng)度，通常，在滿足輪轂結(jié)構(gòu)強(qiáng)度的條件下，盡量減小，則有利于改善流動(dòng)條件。取軸直徑根據(jù)葉輪輪轂直徑應(yīng)取1.21.4倍的軸直徑，根據(jù)設(shè)計(jì)要求，取葉輪所在的軸的直徑為45，所以。取2.5.4 葉輪進(jìn)口直徑的計(jì)算以為直徑的圓面積等于葉輪進(jìn)口去掉輪轂的有效面積，即。按下式確定 式中：泵流量（m3/s）對(duì)雙吸泵取；泵轉(zhuǎn)速（）系數(shù)，根據(jù)統(tǒng)計(jì)資料選取兼顧效率和汽蝕 取2.5.5 葉輪外徑的計(jì)算 取2.5.6 葉輪出口寬度

15、的計(jì)算因?yàn)閮蓚€(gè)葉輪設(shè)計(jì)在一起，所以葉輪出口寬度2.5.7 葉片數(shù)的計(jì)算和選擇葉片數(shù)對(duì)泵的揚(yáng)程、效率、汽蝕性能都有一定的影響。選擇葉片數(shù)，一方面考慮盡量減小葉片的排擠和表面的摩擦；另一方面又要使葉道有足夠的長(zhǎng)度，以保證液流的穩(wěn)定性和葉片對(duì)液體的充分作用。葉輪葉片數(shù)：對(duì)于低比轉(zhuǎn)數(shù)離心泵葉輪，則式中： 葉輪進(jìn)口直徑葉片進(jìn)口直徑葉輪外徑葉片進(jìn)口角 取葉片出口角 取低比轉(zhuǎn)數(shù)葉輪取大值通常采用葉片數(shù)，取該葉輪葉片數(shù)為62.5.8精算葉輪外徑1.葉片出口排擠系數(shù)2.出口軸面速度3.出口圓周速度4.葉輪外徑與假定值接近，不再進(jìn)行計(jì)算。2.5.9 葉輪進(jìn)口速度1.葉輪進(jìn)口圓周速度進(jìn)口分點(diǎn)半徑為式中: 所分的流道

16、數(shù) 從軸線側(cè)算起欲求的流線序號(hào)如圖所示,中間的流線序號(hào)為,所分的流道則:2.葉片進(jìn)口軸面液流過(guò)水?dāng)嗝婷娣e3.C流線處葉片進(jìn)口角(假定) 2.5.10 葉輪出口速度1.出口軸面速度（由上述計(jì)算得） 2. 出口圓周速度3. 出口圓周分速度4. 無(wú)窮葉片數(shù)出口圓周分速度4.校核由軸面投影圖假設(shè),與假設(shè)相近. 2.5.11 葉輪強(qiáng)度計(jì)算一、蓋板強(qiáng)度計(jì)算蓋板中的應(yīng)力主要由離心力造成的，半徑越小的地方應(yīng)力越大，葉輪簡(jiǎn)圖如下圖1-4.11所示：圖2-4.111.葉輪外徑：2.材料密度：3.葉輪簡(jiǎn)圖： 4.葉輪出口圓周速度的值按下式計(jì)算：式中：出口圓周速度系數(shù) 根據(jù)比轉(zhuǎn)數(shù)查葉片泵設(shè)計(jì)手冊(cè)圖5-3得5.在和處的

17、應(yīng)力近似用下式計(jì)算:6.按等強(qiáng)度設(shè)計(jì)蓋板，蓋板任意直徑處的厚度按下式計(jì)算式中：材料密度（） 許用應(yīng)力 對(duì)鋼，對(duì)鑄鐵材料的屈服強(qiáng)度材料的抗拉強(qiáng)度該蓋板符合要求二、葉片厚度計(jì)算根據(jù)葉片工作面和背面的壓力差，可近似得出下面計(jì)算葉片厚度的公式：式中：泵的揚(yáng)程葉片數(shù)葉輪外徑A系數(shù)，與比轉(zhuǎn)數(shù)和材料有關(guān)，查【現(xiàn)代泵技術(shù)手冊(cè)關(guān)醒凡編著，宇航出版社?！勘?9-9取A=3.1根據(jù)實(shí)際情況和鑄造工藝要求取為合適。三、輪轂強(qiáng)度計(jì)算1.葉輪輪轂和軸配合的選擇對(duì)一般離心泵，葉輪和軸是采用過(guò)盈配合，為了使輪轂和軸的配合不松動(dòng)，運(yùn)轉(zhuǎn)時(shí)離心力產(chǎn)生的變形應(yīng)小于軸與輪轂配合的最小公盈。離心力在輪轂中產(chǎn)生的應(yīng)力亦可用下式計(jì)算，即軸與

18、輪轂的配合：孔 軸最大間隙：最小間隙：式中：輪轂平均直徑材料的彈性模量2.輪轂強(qiáng)度計(jì)算輪轂中的應(yīng)力為裝配應(yīng)力（有過(guò)盈時(shí)）和停泵后輪轂和軸心溫差應(yīng)力之和溫差應(yīng)力：安全系數(shù)：2.6 軸的設(shè)計(jì)計(jì)算2.6.1 扭矩的計(jì)算軸按懸臂梁簡(jiǎn)化其受力情況如圖5.3所示式中: 扭矩()計(jì)算功率 取2.6.2 根據(jù)扭矩計(jì)算泵軸直徑的計(jì)算式中: 材料的許用切應(yīng)力() 查【現(xiàn)代泵技術(shù)手冊(cè)關(guān)醒凡編著】 表7-12取現(xiàn)取泵軸的最小軸徑取,泵軸的最大尺寸取2.6.3 畫(huà)出軸的受力簡(jiǎn)圖如圖5.3所示 圖2-5.3葉輪的左邊用螺母鎖緊,右邊用軸套定位,軸套內(nèi)徑取45mm,外徑取60mm。2.6.4 軸的強(qiáng)度計(jì)算（1）葉輪所受徑向

19、力的計(jì)算()式中: 泵揚(yáng)程 葉輪外徑 包括蓋板的葉輪出口寬度() 試驗(yàn)系數(shù) 查【現(xiàn)代泵技術(shù)手冊(cè)關(guān)醒凡編著】 圖17-30取則 （2）葉輪所受徑向不平衡離心力的計(jì)算(N)式中: 最大半徑處的殘余不平衡質(zhì)量(g)取葉輪的最大半徑() 則（3）水平總的受力: 垂直總的受力: （4）計(jì)算水平面支承反力： 計(jì)算垂直面支承反力：（5）計(jì)算水平面彎矩： 如圖5.4所示計(jì)算垂直面彎矩： 如圖5.4所示（6）計(jì)算合成彎矩：如圖5.4所示 （7）計(jì)算當(dāng)量彎矩查【機(jī)械設(shè)計(jì)吳宗澤主編】表2-7 由插入法得 葉輪中線截面處：電動(dòng)機(jī)第一軸承處：如圖5.4所示（8）校核軸徑葉輪中線截面處：電動(dòng)機(jī)第一軸承處： 軸的截面形狀是

20、影響軸剛度的重要因素，當(dāng)將實(shí)心軸改為外徑為原直徑的2倍的空心軸，并使空心軸的質(zhì)量為原實(shí)心軸質(zhì)量的2倍時(shí)，軸的強(qiáng)度提高到實(shí)心軸強(qiáng)度的6.5倍，剛度提高到實(shí)心軸剛度的13倍，所以該空心軸符合要求。2.6.5 軸的彎矩圖 2-5.42.7 殼體壁厚計(jì)算因渦殼幾何形狀復(fù)雜,且受力不均,故難以精確計(jì)算,下面可以用來(lái)估計(jì)壁厚式中: 泵揚(yáng)程(m)泵流量() 許用應(yīng)力(Pa) (鑄鐵)當(dāng)量壁厚,按下式計(jì)算 則2.8 壓出室和吸入室的水力設(shè)計(jì)此處省略NNNNNNNNNNNNNN字，如需全套設(shè)計(jì)和圖紙資料請(qǐng)聯(lián)系扣扣九七一九二零八零零。致謝短短幾個(gè)月的畢業(yè)設(shè)計(jì)即將結(jié)束在文美純老師和劉吉普老師的指導(dǎo)下我成功的完成了畢

21、業(yè)設(shè)計(jì)。在此特向兩為老師表示衷心的感謝！ 通過(guò)這次畢業(yè)設(shè)計(jì)我鞏固了以前的專業(yè)知識(shí)，學(xué)習(xí)了一些新東西。我初步掌握了Pro/ENGINEER和CAD 的一些基本操作，溫習(xí)了工程制圖。并認(rèn)識(shí)到這些軟件的功能強(qiáng)大和自己所學(xué)的不廣與不精。最后，再次感謝文老師和劉老師對(duì)我的幫助。同時(shí)也要感謝我的室有對(duì)我的幫助。參考文獻(xiàn)1.離心泵與軸流泵丁成偉著 南寧：機(jī)械工業(yè)出版社，19852.現(xiàn)代泵技術(shù)手冊(cè)關(guān)醒凡著 北京：宇航出版社，19953.機(jī)械設(shè)計(jì)手冊(cè)（第二卷）機(jī)械設(shè)計(jì)手冊(cè)編委會(huì)編著北京：機(jī)械工業(yè)出版社，2004.84. 機(jī)械設(shè)計(jì)標(biāo)準(zhǔn)應(yīng)用手冊(cè)（第二卷）汪凱著 北京：機(jī)械工業(yè)出版社，1997.8 5.機(jī)械設(shè)計(jì)手冊(cè)

22、單行本。潤(rùn)滑與密封/成大先主編 北京：化學(xué)工業(yè)出版社，2004.16. 材料力學(xué)羅迎社 主編 李卓球 主審 武漢:武漢理工大學(xué)出版社，2007.7 7.機(jī)械設(shè)計(jì)吳宗澤主編 北京：高等教育出版社，2001英語(yǔ)翻譯： Pump's outlineThe pump is the application very widespread general machinery, may say that is place of the fluid flow, nearly has the pump in the work. Moreover, along with science's and

23、 technology's development, pump's application domain is expanding rapidly, according to the over-all state statistics, pump's power consumption approximately composes the national total output of electrical energy 1/5, obviously the pump is natural consumes energy the wealthy and powerfu

24、l family. Therefore, raises the pump technical level to save the energy consumption to have the important meaning.First. Centrifugal pump's principle of workThe drive leads impeller revolving through the pump spindle to have the centrifugal force, under the centrifugal action of force, the liqui

25、d is flung along the leaf blade flow channel to the impeller export, the liquid sends in after the volute collection the eduction tube. The liquid obtains the energy from the impeller, causes the pressure energy and the speed can increase, and depends upon this energy the hydraulic transport to the

26、operating location. while the liquid is flung which exports to the impeller, the impeller eye center has formed the low pressure, has had the differential pressure in the imbibition pot and between the impeller center liquid, in the imbibition pot's liquid under this differential pressure functi

27、on, after inhales the pipeline and pump's suction chamber unceasingly enters in the impeller.Second, centrifugal pump's structure and main spare part A centrifugal pump mainly by the pump body, the impeller, the packing ring, the rotation axis, the axis seals parts and so on box to be compos

28、ed, some centrifugal pumps are also loaded with the guide pulley, the inducer, the balance disc and so on. 1. Pump body: Namely pump's shell, including suction chamber and delivery chamber. Suction chamber: Its function is enables the liquid to flow in evenly the impeller.Delivery chamber: Its f

29、unction collects the liquid, and sends in it the subordinate impeller or guides the eduction tube, at the same time reduces the liquid the speed, causes the kinetic energy to further turn the pressure energy. The delivery chamber has the volute and the guide vane two forms. 2. Impeller: It is in the

30、 centrifugal pump transmits the energy for the liquid only part, the impeller with the bond fixation on the axis, leads revolving along with the axis by the prime mover, passes to through the leaf blade prime mover's energy the liquid.Impeller classification: According to liquid inflow classific

31、ation: Single suction impeller (in impeller's one side has an entrance) and double attracts the impeller (liquid from impeller's lateral symmetry liudao impeller passage). Is opposite according to the liquid in centerline's flow direction classification: Runoff type impeller, axial-flow

32、propeller and interflow type impeller. According to impeller's structural style classification: Shrouded impeller, open type impeller and semi-opened impeller.3. Axis: Is transmits the mechanical energy the important components, the prime mover's torque passes to the impeller through it. The

33、 pump spindle is the pump rotor's major parts, on the axis is loaded with components and so on impeller, axle sleeve, balance disc. The pump spindle depending on the both sides bearing supporting, makes the high speed rotation in the pump, thus the pump spindle in a big way wants the bearing cap

34、acity, to be wear-resisting, to be anti-corrosive. Pump spindle's material selects the carbon steel or the alloy steel and after the quenching and retempering treatment generally.4. Packing ring: Is installs in the rotation impeller and the static pump housing (center-section and guide vane'

35、s assembly) between packing assembly. It is function is through controls between the two gap method, increases in the pump between the high and low pressure cavity the fluid flow resistance, reduces divulging. 5. Axle sleeve: The axle sleeve is uses for to protect the pump spindle, causes it not to

36、corrode and the attrition. When necessity, the axle sleeve may replace. 6. Axis seals: The pump spindle and around packing box between end cover's installs short for axis to seal, mainly prevents in pump's liquid divulging and the air enters in the pump, achieves seals and prevents the air a

37、dmission to cause the pump cavitation goal. the axis seals form: Namely has skeleton's rubber seal, the packing seal and the mechanical seal.7. axial force balancing unit.Third. Centrifugal pump's prime task parameter 1. Current capacity: Namely the pump in unit of time discharges the liquid

38、 quantity, usually indicated with the Unit of volume that mark Q, the unit has m3/h, m3/s, l/s and so on, 2. Lifting: The transportation unit weight's liquid (pump suction flange) (pump discharge flange) from the pump inlet place to the pump exit, its energy's increment, indicated with H, th

39、e unit is m. 3. Rotational speed: Pump's rotational speed is the pump each minute revolving number of times, expressed with N. Electrical machinery rotational speed N generally about 2900 n/min. 4. Net positive suction head: Centrifugal pump's net positive suction head is expressed that pump

40、's performance's main parameter, uses the symbolic representation. 5. Power and efficiency: Pump's power input is shaft power P, is also electric motor's output. Pump's output is the active power.Fourth, pump proper energy loss Pump mechanical energy which obtains from the prime

41、mover, has a part to transform into the liquid energy, but another part because in the pump consumes loses. In the pump all losses may divide into the following several items: 1. Hydraulic loss by the liquid in pump impact, the turbulent flow and the surface friction creates. The impact and the eddy

42、 current loss are because the liquid flow change direction produces. The liquid flows through the flow channel general meeting which contacts to present the surface friction, from this produces the energy loss is mainly decided by flow channel's length, the size, the shape, the surface roughness

43、, as well as liquid speed of flow and characteristic.2. Volumetric loss: volumetric loss was already obtained the energy liquid to have a part to flee the result which in the pump the class and leaked outward. Pump's volumetric efficiency is 0.930.98 generally. Improves the packing ring and the

44、seal structure, may reduce the leakage, raises the volumetric efficiency. 3. Mechanical loss mechanical loss refers to the impeller lap side and the pump housing friction loss between the liquid, namely the disc loses, as well as pump spindle when packing, bearing and balancing unit and so on mechan

45、ical part movement friction loss, generally before primarily.Fifth, pump's speed change-Proportionality law 1. Centrifugal pump's speed change: A centrifugal pump, when its rotational speed change, its rated flow, lifting and the shaft power will have the change according to the certain prop

46、ortion relations. At present, uses the frequency conversion velocity modulation electrical machinery to realize centrifugal pump's speed change, is a new important energy conservation way. 2. proportionality law expression: In the formula, Q, H, N- pump's rated flow, lifting and shaft power

47、The subscript 1,2 express the different rotational speed separately n- rotational speedSixth, centrifugal pump's ratio rotation Compared to the rotation is the comprehensive parameter which derives by the law of similarity, it is the operating mode function, to a pump, the different operating mo

48、de has differently compared to the rotation, for ease of carries on the comparison to the different type pump's performance and the structure, the application optimum condition (the peak efficiency spot) the ratio rotation represents this pump. When chooses the pump, may according to job require

49、ment Q, H and unifies electrical machinery's rotational speed, calculates the ns number, determines pump's type approximately. At that time, used the positive displacement pump generally, at that time, used the centrifugal pump, the interflow pump, the axial flow pump and so on.Seventh,centr

50、ifugal pump's cavitation andinspirationcharacteristic 1.Cavitation phenomenons The pumping station transportation medium's liquid condition and the gas are can transform mutually, the transformed condition is the pressure and the temperature. Under certain temperature, the liquid starts the

51、critical pressure which vaporizes for the vaporization pressure. The temperature is higher, the liquid vaporization pressure is higher. Pump when revolution, if its overflow part local region (for example impeller blade import later somewhere), the liquid absolute pressure drops when pulled out deli

52、vers the liquid at that time under the temperature vaporization pressure, the liquid then in this place starts to vaporize, the bubble formation (air bubble internal pressure approximately was equal to vaporization pressure). When these air bubbles along with liquid flow forward motion to high press

53、ure region, down to around the air bubble high-pressured liquid causes the air bubble to reduce suddenly congeals. While air bubble vanishing, the liquid particle by the high speed packing hole, occurs hits mutually forms the intense pressure surge, causes the overflow part to receive the corrosion

54、and the destruction. The above process is called the cavitation. 2. Cavitation will cause serious results: (1). has the vibration and the noise. (2). is influential to pump's operating performance: When the cavitation develops the certain extent, the steam bubble produces massively, will stop up

55、 the flow channel, will cause pump's current capacity, lifting, the efficiency and so on obviously to drop. (3). will have the destruction to flow channel's material quality: Is mainly nearby the leaf blade entrance the metal weary disintegration.3. centrifugal pump's inspiration characteristic: (1). Pump has the cavitation basic condition is: Under leaf blade entrance lowest liquid flow pressure <= this temperature liquid vaporization pressure .(2). effective net positive suction head: The pump entry (potential head is the entire flood peak which zero