外文翻譯--石油天然氣工程標(biāo)準(zhǔn)手冊

1、<p>　　畢業(yè)設(shè)計外文文獻翻譯</p><p>　　《石油天然氣工程標(biāo)準(zhǔn)手冊》</p><p><b>　　泵</b></p><p>　　泵是一種將液體從一個位置驅(qū)動到另一個位置的機械。通常情況下，工程機械用泵是用來移動不可壓縮液體（或接近不可壓縮）或流體的泵。泵是我們?nèi)粘Ｉ钪凶钤缡褂玫臋C械設(shè)備，也是眾多使用的機械設(shè)備之一。泵更

2、是石油，天然氣工業(yè)的一個重要組成部分，它的用途貫穿整個工業(yè)生產(chǎn)，從鉆探操作到最終把產(chǎn)品交付給顧客。</p><p><b>　　泵的分類</b></p><p>　　泵通常分兩類：位移式泵和動力式泵。在石油，天然氣工業(yè)上最廣泛使用的是往復(fù)式活塞泵，回轉(zhuǎn)泵和離心泵，也只有這些泵常常被細(xì)致的探索和深入地研究。往復(fù)式回轉(zhuǎn)泵的顯著特點是它與活塞芯子的運動及液泵的數(shù)量有相當(dāng)密切

3、的關(guān)系。因此，動力泵液體置換在理論上等于單位時間上掃過泵芯子的體積。圖3.3.3顯示了典型式動力泵壓力變化與流量變化的框圖?？梢钥闯觯杭词贡脙?nèi)壓力產(chǎn)生較大的波動，泵的液體排量也不會發(fā)生很大的變化。液體運動時的阻力由泵提供的能量來來抵抗。如果泵內(nèi)的壓力增加，且又要保持活塞運動狀態(tài)不變，泵的每次沖擊力都會有一定的增加，這也是往復(fù)式活塞泵也叫做動力泵的原因。在社會生產(chǎn)實踐中，壓力對這些泵的流量會產(chǎn)生很大的影響。這是因為當(dāng)泵的壓力增加時系統(tǒng)會產(chǎn)

4、生一定程度上的泄漏，泄漏和壓力是成一定比例的，特別是當(dāng)壓力超過特定許用值時產(chǎn)生的現(xiàn)象更為明顯。泵缸中液體理論流量和實際流量產(chǎn)生的差別叫做流量損失。圖3.3.3為流量損失圖。在動力泵特別是離心泵中，泵內(nèi)流體的壓力決定著泵的卸荷率，在圖3.3.4中有所顯示。</p><p><b>　　往復(fù)泵</b></p><p>　　活塞泵是動力泵中形式最簡單的一種泵。泵由多種動力源

5、驅(qū)動，如內(nèi)燃機和電動機等。泵運轉(zhuǎn)時，分離的泵系統(tǒng)由電力傳動裝置連接到動力源上，泵缸內(nèi)的流量由活塞的數(shù)量，一些元件的尺寸（鉆孔和沖擊速度）所決定。循環(huán)泵通常設(shè)計成定容量和定壓力式的，這些因素由應(yīng)用條件所決定。一旦泵的壓力和流量確定，設(shè)計者就可以跟據(jù)這些條件來確定柱塞孔，活塞往復(fù)速率的變化和動力源為滿足條件所需要的產(chǎn)生動力。往復(fù)式活塞泵通常又分為垂直式往復(fù)泵和水平式往復(fù)泵兩種。</p><p><b>　　

6、單作用泵</b></p><p>　　單作用泵活塞在一次往復(fù)過程中只有一個工作行程。當(dāng)動力裝置驅(qū)動活塞壓縮時，泵的體積縮小，液缸腔內(nèi)工作液受到擠壓，液缸缸內(nèi)部壓力逐漸增大（液體視為不可壓縮的）吸入閥因受擠壓而被迫關(guān)閉，排出閥受力被推開，使液體排出泵缸，進入排出管道。</p><p>　　活塞運動由旋轉(zhuǎn)的曲軸帶動曲軸連桿完成，而曲軸則由電動機通過傳動裝置帶動旋轉(zhuǎn)。單作用泵通常有3

7、個、5個，甚至有7個活塞組成。帶有奇數(shù)個活塞的單作用泵經(jīng)試驗顯示液壓缸內(nèi)液體流動比較平穩(wěn)。至少采用3個活塞的泵可以減少泵缸內(nèi)的液體波動。通常具有3個活塞的單作用泵叫做三缸泵，含5個或7個活塞的單作用泵叫做多缸泵。</p><p><b>　　雙作用泵 </b></p><p>　　雙作用泵活塞在一次往復(fù)過程中有兩個工作行程。液缸中的液體被活塞分為兩個密封腔。當(dāng)活塞向一

8、側(cè)液腔推動時，受擠壓的液腔縮小，缸內(nèi)液體壓力增大，吸入閥被壓緊，排出閥受力打開，將一部分液體排出缸外；與此同時，在另一液腔中液腔的體積增大，液體壓力降低，排出閥由于受到吸力而壓緊，吸入閥則在外力作用下被推開，一部分液體進入腔中，一個往復(fù)過程完成兩次液體吸入和排出。含有一個活塞的雙作用泵叫做單缸雙作用泵，含有兩個活塞的雙作用泵叫做雙缸雙作用泵。</p><p><b>　　流動特性</b>&l

9、t;/p><p>　　所有往復(fù)泵的流量都產(chǎn)生一定的波動性。這是由活塞的停止和反向運動造成的結(jié)果。靜止和反向運動的瞬間理論流量損失降為零。因此，泵缸內(nèi)液體的流量是時間的函數(shù)。隨時間的改變而呈周期性變化，如圖3.3.3所示。根據(jù)對往復(fù)泵的流量不均勻性的描述可知，泵的缸數(shù)越多，各缸合成的理論流量越趨于均勻，選用奇數(shù)缸比偶數(shù)缸的效果更為明顯。但多缸泵結(jié)構(gòu)復(fù)雜，制造和維修較困難，因而通過增加液缸數(shù)來改變泵的流量不均勻度受到一定

10、的限制。在社會生產(chǎn)實踐中為了改善缸中流量不均勻的現(xiàn)象，通常采用的措施是在泵的吸入口和排出口設(shè)置空氣室。安裝在排出口的空氣室叫做排出口空氣室，安裝在吸入口的空氣室叫做吸入口空氣室，當(dāng)往復(fù)泵的排量增加到大于平均排量時，排出管道壓力升高，使空氣室內(nèi)的氣體收到壓縮，體積縮小，一部分氣體進入空氣室儲存起來，而不進入排出管道。當(dāng)泵的瞬時排量小于泵的平均排量時，排出管道壓力降低，空氣室內(nèi)被壓縮的氣體體積膨脹起來，將空氣室內(nèi)儲存的那部分液體基礎(chǔ)空氣室進

11、入排出管道，以補償這部分泵排量的不足。從而起調(diào)節(jié)作用，克服排量不均勻現(xiàn)象。往復(fù)式泵的流量不均勻度過大會使沖洗液攜帶巖粉的能力降低，容易造成埋鉆、糊鉆等事故；會導(dǎo)致</p><p><b>　　泵性能的要求</b></p><p>　　鉆井泵的排量要能簡便、迅速地在較大范圍進行調(diào)節(jié)，最好能實現(xiàn)無級調(diào)節(jié)。鉆井泵的排出壓力也要能在較大范圍進行調(diào)節(jié)當(dāng)根據(jù)鉆進工藝規(guī)程將泵量調(diào)定

12、以后，它不能隨泵的排出壓力的變化而發(fā)生變化。工作可靠、易損件壽命長、便于維修保養(yǎng)。要能適應(yīng)不利條件下的工作。運移性要好</p><p><b>　　單作用泥漿泵活塞</b></p><p>　　安裝在泥漿泵中機構(gòu)的單作用活塞包括一個活塞和末端在腔中運動的抬肩。裝置包括安裝在末端肩部的圓法蘭盤，一個安裝在與法蘭盤邊緣相接近的活塞蓋。這兩部分由墊圈和螺絲連接在活塞的末端。

13、連接活塞部分有活塞桿，它包括一個圓柱形尾部和一個呈放射狀的抬肩，活塞裝配包括平的圓形法蘭盤，它的外圓直徑小于活塞桿缸的內(nèi)圓直徑。法蘭的中心有一個孔，孔的直徑與前面所說的活塞桿末端的直徑相等，安裝的法蘭與靠近肩部的圓柱末端相配合，目的是使法蘭和活塞桿之間形成密封。安裝在靠近法蘭尾部的圓形平轂，它的外圓直徑小于法蘭的外圓直徑，轂的中央有一個孔，孔的直徑大小等于活塞桿末端部分直徑，轂有一個周向較厚的圓形的可移動的橡膠活塞杯，它與前面所說的法蘭

14、相連。它的外緣有一個十分光滑的環(huán)，環(huán)的外圓直徑比前文所說的缸筒內(nèi)徑大，活塞杯有一個中心孔，孔的直徑與轂的外圓直徑相同?；钊闹行妮S向厚度至少要等與轂的厚度。安裝在活塞尾部的可以移動的圓形平墊圈，它的外圓直徑大于轂的外圓直徑，而內(nèi)圓直徑正好等于活塞桿末端直徑?？s緊螺母的螺紋與活塞桿末部相連接，促使墊圈與轂加緊。圖為往復(fù)運動的基本區(qū)別，活塞工作在密閉的圓柱形液缸中?；钊着c柱塞缸的區(qū)</p><p><b&g

15、t;　　泵的工作原理</b></p><p>　　一般來說往復(fù)泵通常分為兩種：抽水泵和動力泵。當(dāng)運動時又可分為單作用往復(fù)泵和雙作用往復(fù)泵。抽水泵是一種單作用泵。當(dāng)活塞借助外力向外抽出時，液腔內(nèi)壓力降低，在外界大氣壓力作用下，排出閥被關(guān)緊，吸入閥被推開，液體進入到液缸中；然后活塞借助外力向壓縮時，壓力增加，吸入閥被頂死，而排出閥被推開，液體排出缸外，活塞進行往復(fù)運動，液體被吸入又被排出。動力泵的活塞運動

16、與之相似。</p><p><b>　　泥漿泵</b></p><p>　　泥漿泵消耗了旋轉(zhuǎn)鉆探系統(tǒng)總馬力的60%以上。當(dāng)進行鉆探時，泥漿泵通過泥漿循環(huán)系統(tǒng)來循環(huán)鉆探泥漿。泥漿泵向孔內(nèi)輸送沖洗液以清洗孔底，冷卻鉆頭和潤滑鉆具。在使用液動沖擊鉆具時，泥漿泵還能作為能源裝置。</p><p>　　像在圖4.4.1所示的有兩個液壓缸體泵通常叫做雙缸泵

17、，有三個液壓缸組成的泵叫做三缸泵，如圖4.4.2所示。雙缸泵通常用于雙重作用，三缸泵則用于單獨作用。泥漿泵由動力端和液力端組成。動力端如圖4.4.4所示，將電動機（通常為柴油機和電動機）軸上的功率輸送到泵的機軸上；液力端則用來把液體泵出缸外，液力端的橫截面如圖4.4.5所示。動力端的功能，是將動力機的回轉(zhuǎn)運動轉(zhuǎn)變?yōu)榛钊?或柱塞)的直線往復(fù)運動。它包括傳動離合裝置、變速減速裝置和曲柄連桿。它們的相互位置與安排決定著泵的總體結(jié)構(gòu)型式，決定著

18、泵的驅(qū)動方案及結(jié)構(gòu)方案的選擇。動力端的主要零部件包括皮帶輪，離合器曲軸箱體及其中的傳動軸，齒輪副，曲軸，連桿及十字頭滑塊。液力端油泵頭體、缸套 、活塞 、活塞桿吸入閥和排出閥等組成，它的作用是通過活塞在缸套中作往復(fù)運動形成液缸容腔變化，完成能量轉(zhuǎn)化，實現(xiàn)吸入和排出液體。</p><p><b>　　泵的安裝</b></p><p>　　泵的抽水馬達被泥漿泵引長，主要依

19、靠吸水管系統(tǒng)而呈機械形式排列，當(dāng)離心泵（如輔助泵幫助把泥漿將送入泥漿泵）不用時，泵的液壓缸內(nèi)充滿了靜態(tài)的液體。泵缸中填充物得不完善，將產(chǎn)生噪音，產(chǎn)生破壞性的壓力，嚴(yán)重縮短了泥漿泵的使用壽命。在較高速運動的活塞缸中，填充物越來越受到人們的重視，成為一個很大的技術(shù)難題。抽水泵壓力通過吸入閥和吸入閥座時受到不同程度的損失，在通常情況下不可避免。由于最大限度可以利用的大氣壓力為14.7PSI（海平面）,因此安裝在泵體底部的吸水坑應(yīng)該被除去，取而

20、代之的是吸水泵，它安裝在相對于泵體比較高的位置，以確保獲得正的吸水壓頭。圖4.4.6所顯示的是一種相對比較理想的安裝方式，它受到最小的摩擦力和較小的慣性。錯誤的安裝抽水泵的入口相當(dāng)于增加30倍管道內(nèi)部摩擦力。多余的吸入管道摩擦力是導(dǎo)致吸入口凝聚物突然增大的主要因素，使吸入管的直徑明顯減小，吸入管底部和許多裝置順著吸入管安裝，目的是能夠最大限度的降低吸入速度和減少泥漿質(zhì)量。通常在實際生產(chǎn)中，采用直徑較大且較短的管道。由于抽水泵的功用有時不

21、能很好的滿足人們的要求，就會采用上水泵作為輔助工具，這種方式已經(jīng)廣泛地被現(xiàn)代生產(chǎn)中所使用</p><p><b>　　泵內(nèi)泥漿的冷卻</b></p><p>　　150度的泥漿會給泥漿泵帶來很大的破壞性，液壓缸中的泥漿在較低壓力或有真空存在下會沸騰，因而會大大降低泥漿泵的效率，當(dāng)有油存在時，熱的泥漿還會加速管道內(nèi)部橡膠部件的損壞。在社會實際生產(chǎn)中，通常采用帶有冷卻表面

22、的大泥漿桶來減少這種現(xiàn)象所帶來的破壞。</p><p><b>　　油氣和氣體的分離</b></p><p>　　當(dāng)進行吸氣沖程時，缸內(nèi)壓力降低，以氣泡形式存在于泥漿中的油氣和氣體會發(fā)生膨脹，某種程度上降低了抽水泵的效率。基于泥漿底部的油氣也會自然的加速橡膠部件的老化，通常分離油氣較為困難，因而實際生產(chǎn)中人們常常靠改變泥漿的組成物來減少這種現(xiàn)象給泵所帶來的破壞。<

23、;/p><p><b>　　沉淀物</b></p><p>　　通常泥漿具有很好的潤滑性，但也會被沒有從泥漿中濾出去的細(xì)沙所破壞。采用適當(dāng)?shù)某恋韯┖驼駝悠鲿p少這種麻煩，有時候也采用泥漿除沙器。</p><p><b>　　泵的卸出只管</b></p><p>　　一個設(shè)計較差的卸出只管會引起振動波動和

24、過大的壓力，這一部分安裝應(yīng)該盡可能的短和采用直接安裝避免任何轉(zhuǎn)彎。通常小的氣室由泵內(nèi)壓力自行來填充，只受到一個中等的緩沖作用，為了達到最佳效果，應(yīng)盡可能采用大的充氣室。這部分泵排量的不足。從而起調(diào)節(jié)作用，克服排量不均勻現(xiàn)象。采用預(yù)先加壓也可以減少波動和過大的壓力 </p><p><b>　　泵的磨損</b></p><p>　　泵易損件主要包括缸套、活塞(或柱塞及其

25、盤根)、閥和閥座、活塞桿及其盤</p><p>　　根等。都是往復(fù)運動件及其密封摩擦副的對磨零件，它們有兩個共同特點：一是對磨零件是彈性體，它可以變形；二是在工作過程中承受著一定的壓力差。因此它與兩個剛性零件形成的摩擦副不同，其摩擦和磨損規(guī)律的研究更困難。泵易損件的磨損，一般又分為正常磨損和非正常磨損。易損件的結(jié)構(gòu)、加工制造質(zhì)量與裝配公差；材料性能；摩擦副的潤滑；泵所輸送介質(zhì)的排量，壓力，溫度，化學(xué)性質(zhì)，介質(zhì)中所

26、含磨礪性顆粒的性質(zhì)，形狀，大小，多少；維修、保養(yǎng)、包裝、運輸及儲存等工作性質(zhì)的好壞等都是影響易損件壽命的主要因素。</p><p><b>　　泵的操作</b></p><p>　　活塞在干燥的液缸中沖擊可能會損壞襯套，當(dāng)泵不受重力，液缸長時間不動或活塞不停的往復(fù)運動都會導(dǎo)致活塞泵吸入閥的開啟</p><p><b>　　清洗進水岐管

27、</b></p><p>　　由于泥漿泵的管路常被凝固的沙子和抽水坑中的碎片，殘骸所填充，這將導(dǎo)致不規(guī)則的低速振動。多檢查和清洗抽水泵的進水岐管是有必要的。如果不能經(jīng)常清洗，采用過濾器的辦法也是可行的。</p><p><b>　　不循環(huán)材料</b></p><p>　　通常一些特殊的固體，如堅果殼，石灰石，膨脹的石灰?guī)r等夾雜在泥漿

28、中，嚴(yán)重的影響鉆井的野外作業(yè)。大部分的無用填充材料都會影響泵中某些元件的使用壽命。當(dāng)它們堆積在閥體和閥座之間時會特別的堅硬而難以去除。</p><p><b>　　清洗出口過濾器</b></p><p>　　出口過濾器廠被閥管和膠管堵塞，這將增加泵內(nèi)的壓力，而這并不顯示在壓力表上。過濾器應(yīng)該經(jīng)常清洗，防止壓力堆積</p><p><b&g

29、t;　　泵室</b></p><p>　　泵室是專門為高壓設(shè)備服務(wù)的，通常用較好的材料，采用特別加工方法制造而成。在鉆探設(shè)備的氣室中，所有金屬零件都要采取保護，防止其銹蝕和損壞，橡膠零件要避免過度的扭曲，不能暴露在光、熱、油中。一般而言，零件要用抗腐蝕的材料保護起來。粗制活塞會導(dǎo)致泵體內(nèi)部的過早損壞，把它們隨意地放在缸中都會損壞泵缸。偶然從泵缸內(nèi)脫落的金屬零件，應(yīng)該及早除去換上新的零件。</p&

30、gt;<p>　　《Standard Handbook of Petroleum & Natural Gas Engineering》 </p><p>　　By Lyons, William C.; Plisga, Gary S.Publication: Burlington, MA Elsevier, 2005</p><p><b>　　畢業(yè)設(shè)計外文

31、原文</b></p><p>　　《Standard Handbook of Petroleum & Natural Gas Engineering 》</p><p>　　by Lyons, William C.; Plisga, Gary S.Publication: Burlington, MA Elsevier, 2005</p><p&g

32、t;<b>　　3.3 PUMPS</b></p><p>　　Pumps are a mechanical device that forces a fluid to move</p><p>　　from one position to another. Usually a pump refers to the</p><p>　　mech

33、anical means to move incompressible (or nearly incompressible)</p><p>　　fluid or liquid. Pumps are our earliest machine and are to this day one of our most numerous mechanical devices. Pumps are a very essen

34、tial part of the oil and gas industry. They are used throughout the industry, from drilling</p><p>　　operations through to final delivery to the customer.</p><p>　　3.3.1 Classifications</p>

35、;<p>　　Pumps are classified into two basic classes, displacement</p><p>　　and dynamics. The most widely used pumps in the oil and gas industry</p><p>　　are reciprocating displacement pump

36、s (in particular piston</p><p>　　plunger type), the rotary displacement pump, and the centrifugal</p><p>　　dynamic pump. Only these pumps will be discussed in detail.</p><p>　　The r

37、eciprocating and rotary positive displacement pumps</p><p>　　primary characteristic is that they have a nearly direct relationship</p><p>　　between the motion of the pumping elements and</p&g

38、t;<p>　　the quantity of liquid pumped. Thus, in positive displacement</p><p>　　pumps liquid displacement (or discharge from the</p><p>　　device) is theoretically equal to the swept volume

39、 of the</p><p>　　pumping element. Figure 3.3.3 shows the typical positive</p><p>　　displacement plot of discharge rate Q (ft3/s) versus pressure</p><p>　　P (lbs/ft2) [3]. The discha

40、rge rate remains the same</p><p>　　(assuming a constant rate of rotation for the system) regardless</p><p>　　of the pressure in the flow. The pressure in the flow</p><p>　　is, of co

41、urse, the result of resistance in the flow system</p><p>　　the pump discharges to. If the resistance increases, rotation</p><p>　　can be maintained and more force applied to each stroke</p>

42、;<p>　　of the pump (i.e., power). This is why the reciprocating piston</p><p>　　plunger pump is also called a power pump. In practice,</p><p>　　pressure does have some influence on the ca

43、pacity of these</p><p>　　pumps. This is because as the pressure increases, there is</p><p>　　some leakage of the seals in the system. This leakage is</p><p>　　somewhat proportional

44、to the pressure, particularly beyond</p><p>　　some characteristic pressure related to the seals. The difference</p><p>　　between theoretical flow and the actual flow of a pump</p><p&g

45、t;　　is often referred to as slip. This slip is shown in Figure 3.3.3. </p><p>　　In the dynamic pump, in particular, the centrifugal pump,</p><p>　　the discharge rate Q is determined by the resis

46、tance pressure</p><p>　　P in the flow system the pump discharges to (assuming</p><p>　　some given speed of the pump). This is illustrated in Figure 3.3.4. </p><p>　　3.3.3 Reciprocat

47、ing Pumps</p><p>　　The piston plunger pump is the simplest form of a positive</p><p>　　displacement pump. These pumps can be powered by</p><p>　　a variety of prime movers, internal

48、combustion engines, and</p><p>　　electric motors (and in some cases, powered by a gas turbine</p><p>　　motor). In such applications, the separate pump unit is</p><p>　　connected to

49、the prime mover by a power transmission.</p><p>　　The capacity of a pump is determined by the number of</p><p>　　plungers or pistons and the size of these elements (bore and</p><p>

50、　　stroke). A reciprocating pump is usually designed for a specific</p><p>　　volumetric rate capacity and pressure capability. These</p><p>　　factors are set by the application. Once the volumetr

51、ic rate</p><p>　　capacity and pressure capability are known, a designer can</p><p>　　determine the plunger piston bore and stroke the rotation</p><p>　　speed range and the power of

52、the prime mover needed to</p><p>　　complete the system. Reciprocating pumps are fabricated in both horizontal andvertical configurations.</p><p>　　3.3.3.1 Single-Acting Pump</p><p>

53、　　A single-acting pump has only one power (and discharge)</p><p>　　stroke for its pistons. Such a pump brings fluid into its chamber</p><p>　　through the inlet or suction value or the piston is

54、drawn</p><p>　　backward to open the chamber. To discharge the fluid, the</p><p>　　inlet valve is closed and the outlet valve opened as the piston</p><p>　　is forced forward to push

55、the fluid from the chamber into</p><p>　　the discharge line. The piston motion is accomplished by a</p><p>　　rotating crankshaft that is connected to the piston by a piston</p><p>　

56、　rod much like an internal combustion piston engine. The</p><p>　　rotating crankshaft of the pump is rotated by the rotational</p><p>　　power of the prime mover (through a transmission) [7].<

57、/p><p>　　The single-action pump is usually available with three, five</p><p>　　and even seven pistons. The odd number of pistons allows</p><p>　　the pump to be rotationally balanced, a

58、nd the use of at least</p><p>　　three pistons reduces the discharge pulsation of these single-acting</p><p>　　pumps. A three piston pump single-action pump is</p><p>　　called a trip

59、lex pump. A five piston, or seven piston single -acting</p><p>　　pump is called a multiplex pump.</p><p>　　3.3.3.2 Double-Acting Pump</p><p>　　Double-acting pumps have two power str

60、okes. As a piston</p><p>　　of the pump is pushed forward, the fluid is discharged from</p><p>　　the forward chamber into the discharge line (much like a</p><p>　　single-action pisto

61、n). But during this same stroke, the chamber</p><p>　　behind the piston (which contains the connecting rod)</p><p>　　is being filled via that chamber’s inlet valve (Figure 3.3.5).</p><

62、;p>　　When the forward power stroke is complete and the fluid discharged</p><p>　　fromthe chamber in front of the piston, the chamber</p><p>　　behind the piston is filled. The crankshaft conti

63、nues to rotate,</p><p>　　requiring the piston to begin a rearward stroke. During this</p><p>　　stroke the fluid behind the piston is forced from its chamber</p><p>　　into the discha

64、rge line via the outlet valve and the chamber</p><p>　　in front of the piston refills via its inlet valve [7].</p><p>　　Double-acting pumps are usually available with one or twopistons.</p>

65、;<p>　　A one-piston double-action pump is called a double-acting</p><p>　　simplex (since there are older single-action steam and pneumatic</p><p>　　driven simplex pumps).A two piston doub

66、le-action pump is called a duplex pump.</p><p>　　3.3.3.3 Flow Characteristics</p><p>　　All reciprocating pumps have a pulsating discharge. This is</p><p>　　the result of the piston

67、motion as it stops and reverses. At</p><p>　　this moment, the flow from that piston theoretically drops</p><p>　　to zero. Thus, the discharge curves as a function of time</p><p>　　a

68、re those illustrated in Figure 3.3.6.By having two or more pistons the pulsation of the discharge from the pump can besmoothed out and the magnitude of the pulsation reduced ifthe pistons motions are timed for proper dy

69、namic balancingof the pump (Figure 3.3.7). For those pumps that have largepulsations, a cushion change (or accumulator) may be used</p><p>　　in the discharge line to reduce or eliminate the pulsations</p&

70、gt;<p>　　(Figure 3.3.8).</p><p>　　Single acting mud pump piston </p><p>　　Disclosed is a single acting mud pump piston assembly adapted for use in a mud pump mechanism including a pi

71、ston and having an end portion with a shoulder reciprocatingly mounted in a cylinder. The assembly includes a circular flange mounted on the end portion in abuttment with the shoulder. A hub is removably mounted on the e

72、nd portion in abuttment with the flange. A piston cap is mounted about the hub in abuttment with the flange. The assembly is held together by a washer and a nut engaging th</p><p>　　A piston assembly for use

73、 in a single acting mud pump including a cylinder and a piston rod reciprocatingly mounted in the cylinder, said piston rod including a cylindrical end portion and a radially outwardly extending shoulder, said piston ass

74、embly comprising: a circular planar flange having an outside diameter less than the inside diameter of the cylinder and having a bore through the center thereof, said bore having a diameter substantially equal to the dia

75、meter of said cylindrical end porti</p><p>　　A single acting mud pump mechanism which comprises: a cylinder having an inside diameter; a piston rod reciprocatingly mounted in said cylinder, said piston rod i

76、ncluding a threaded cylindrical end portion and a radially outwardly extending shoulder; a circular planar flange removably mounted on said end portion in abuttment with said shoulder and having an outside diameter less

77、than the inside diameter of the cylinder and having a bore through the center thereof, said bore having a diameter sub</p><p>　　Principles of Operation</p><p>　　In general (and with respect to t

78、he way that the water is handled),</p><p>　　reciprocating pumps may be classified as lift pumps or force pumps,</p><p>　　which in turn, are either single-acting or double-acting pumps.</p>

79、<p>　　Lift Pumps</p><p>　　A lift pump is a single-acting pump; it consists of an open cylinder</p><p>　　and a discharge or bucket-type valve (see Figure 5-3). An open</p><p>

80、　　cylinder and a discharge or bucket-type valve in combination are the</p><p>　　basic parts of the lift pump—it lifts the water, rather than forces it.</p><p>　　In the lift pump, the bucket valv

81、e is built into the piston and moves</p><p>　　upward and downward with the piston.</p><p>　　A four-stroke cycle is necessary to start the lift pump in operation</p><p>　　(see Figure

82、 5-4). The strokes are as follows:</p><p>　　_ Air exhaust—The piston descends to the bottom of the cylinder,</p><p>　　forcing out the air.</p><p>　　_ Water inlet—On this upward stro

83、ke, a vacuum is created.</p><p>　　Atmospheric pressure causes the water to flow into the</p><p>　　cylinder. After the pump has been primed and is in operation, the working</p><p>　　

84、cycle is completed in two strokes of the piston—a downward stroke</p><p>　　and an upward stroke (see Figure 5-5). The downward stroke of the</p><p>　　piston is called the transfer stroke, and th

85、e upward stroke is called</p><p>　　the intake and discharge stroke, because water enters the cylinder</p><p>　　as the preceding charge of water is being discharged.</p><p>　　Force P

86、umps</p><p>　　The force pump is actually an extension of a lift pump, in that it</p><p>　　both lifts and forces the water against an external pressure. The</p><p>　　basic operating

87、principle of the force pump is that it forces water</p><p>　　above the atmospheric pressure range, as distinguished from the lift</p><p>　　pump, which elevates the water to flow from a spout. &l

88、t;/p><p>　　4.4 MUD PUMPS</p><p>　　Mud pumps consume more than 60% of all the horsepower</p><p>　　used in rotary drilling. Mud pumps are used to circulate</p><p>　　drilling

89、 fluid through the mud circulation system while</p><p>　　drilling. A pump with two fluid cylinders, as shown in Figure</p><p>　　4.4.1, is called a duplex pump. A three-fluid-cylinder pump, as<

90、;/p><p>　　shown in Figure 4.4.2, is called a triplex pump. Duplex pumps</p><p>　　are usually double action, and triplex pumps are usually</p><p>　　single action. Pumps with six chamber

91、s are commercially</p><p>　　available as well (Figure 4.4.3).</p><p>　　Mud pumps consists of a power input end and a fluid output</p><p>　　end. The power input end, shown in Figure

92、4.4.4 transfers</p><p>　　power from the driving engine (usually diesel or electric) to</p><p>　　the pump crankshaft. The fluid end does the actual work of</p><p>　　pumping the fluid

93、. A cross-section of the fluid end is shown</p><p>　　in Figure.4.4.5.</p><p>　　4.4.1 Pump Installation</p><p>　　4.4.1.1 Suction Manifold</p><p>　　The hydraulic horsepow

94、er produced by mud pumps depends</p><p>　　mainly on the geometric and mechanical arrangement of the</p><p>　　suction piping. If suction-charging centrifugal pumps (e.g.,</p><p>　　au

95、xiliary pumps that help move the mud to the mud pump)</p><p>　　are not used, the pump cylinders have to be filled by the</p><p>　　hydrostatic head.</p><p>　　Incomplete filling of th

96、e cylinders can result in hammering,</p><p>　　which produces destructive pressure peaks and</p><p>　　shortens the pump life. Filling problems become more</p><p>　　important with hig

97、her piston velocities. The suction pressure</p><p>　　loss through the suction valve and seat is from 5 to</p><p>　　10 psi. Approximately 1.5 psi of pressure is required for</p><p>　

98、　each foot of suction lift. Since the maximum available atmospheric</p><p>　　pressure is 14.7 psi (sea level), suction pits placed</p><p>　　below the pump should be eliminated. Instead, suction

99、tanks</p><p>　　placed level with or higher than the pump should be used to</p><p>　　ensure a positive suction head. Figure 4.4.6 shows an ideal</p><p>　　suction arrangement with the

100、 least amount of friction and low</p><p><b>　　inertia.</b></p><p>　　A poorly designed suction entrance to the pump can produce</p><p>　　friction equivalent to 30 ft of p

101、ipe. Factors contributing</p><p>　　to excessive suction pipe friction are an intake connection</p><p>　　with sharp ends, a suction strainer, suction pipe with a</p><p>　　small diame

102、ter, long runs of suction pipe, and numerous fittings</p><p>　　along the suction pipe. Minimizing the effect of inertia</p><p>　　requires a reduction of the suction velocity and mud weight.</

103、p><p>　　It is generally practical to use a short suction pipe with a</p><p>　　large diameter.</p><p>　　When a desirable suction condition cannot be attained,</p><p>　　a ch

104、arging pump becomes necessary. This is a common</p><p>　　solution used on many modern rigs. </p><p>　　4.4.1.2 Cooling Mud</p><p>　　Mud temperatures of 150? can present critical suct

105、ion problems.</p><p>　　Under low pressure or vacuum existing in the cylinder</p><p>　　on the suction stroke, the mud can boil, hence decreasing</p><p>　　the suction effectiveness. F

106、urthermore, hot mud accelerates</p><p>　　the deterioration of rubber parts, particularly when oil is</p><p>　　present. Large mud tanks with cooling surfaces usually solve</p><p>　　t

107、he problem.</p><p>　　4.4.1.3 Gas and Air Separation</p><p>　　Entrained gas and air expands under the reduced pressure</p><p>　　of the suction stroke, lowering the suction efficiency

108、. Gas</p><p>　　in water-base mud may also deteriorate the natural rubber</p><p>　　parts used. Gases are usually separated with baffles or by</p><p>　　changing mud composition.</p