10L真空攪拌機設計【說明書+CAD】
10L真空攪拌機設計【說明書+CAD】,說明書+CAD,10L真空攪拌機設計【說明書+CAD】,10,真空,攪拌機,設計,說明書,仿單,cad
- 畢業(yè)設計(論文) 第30頁共30頁目錄摘 要 - 3前 言 - 4設計題目 - 4第一章總體方案設計 - 4第二章傳動系統(tǒng)總體設計 - 5 第一節(jié)傳動系統(tǒng)的選擇 - 5 第二節(jié) 電動機選擇 - 6 第三節(jié) 聯(lián)軸器的選擇 - 7 第四節(jié) 減速器的選擇 - 9 第五節(jié) 旋轉(zhuǎn)盤的設計 - 13 第六節(jié) 軸上鍵和鍵槽的選擇 - 14第三章 箱體的設計 - 16第四章 攪拌系統(tǒng)的設計 - 18 第一節(jié) 攪拌桶的設計 - 18 第二節(jié) 桶蓋的設計 - 19 第三節(jié) 攪拌葉片的設計 - 21 第四節(jié) 攪拌軸的設計 - 22第五章 橫梁組件的設計 - 26第六章 支撐軸的設計 - 27第七章 其他 - 28 第一節(jié) 公差等級的選擇 - 28 第二節(jié) 粗糙度的選擇 - 28第八章 設計心得與致謝辭 - 29參考文獻 - 30摘要摘要:真空攪拌機是生產(chǎn)人造瑪瑙.人造大理石.人造花崗巖等高分子合成材料的專用設備。他能抽掉漿料攪拌過程中產(chǎn)生的氣泡,又能很好的防止空氣二次混入漿內(nèi)。只有用它做出的人造石板材截面,背面才能真正的消除氣泡的存在。板材才能在耐水.耐磨方面大大提高,做出的產(chǎn)品才能堅實;細膩;光亮;高雅,才能充分體現(xiàn)出產(chǎn)品的魅力所在。攪拌過程中因為空氣的不存在,輔料的用 量還可以大大減少.關鍵字:真空攪拌機Summary:The vacuum mixer is used to produce the high mark son synthesizes the appropriation equipments of the material.such as the artificial gate,Artificial marble,Artificial granite etc. It can take out the syrup to anticipate to mix blend the process to steep in the output spirit, again good preventfrom the air sneaking into the syrup two times inside. Only make the artificial slab of stone material of to cut the noodles with it, back then can the existence of the real cancellation spirit bubble. The plank material then can at bear the water.Bear to whet the aspect to raise consumedly, the product that do then can solid,Delicate,Shining,Elegant, then can well the body appears the magic power place of the product.the process of the mix blend the process in because of the nonentity of the air, the dosage that assists to anticipate can also reduce consumedly.Key word: Vacuum mixer前言隨著社會的發(fā)展,人們的生活水平的提高,人造瑪瑙、人造大理石、花崗巖等樹脂合成人造石材裝飾材料越來越受到消費者的喜愛,越來越多的家庭在裝潢上傾向于使用這些人造石材而真空攪拌機是人造石材制造的關鍵設備之一,適用于人造石材料的攪拌,并在攪拌中抽除氣泡,從而達到既均勻又除氣泡的理想效果。設計題目10L真空攪拌機設計。攪拌筒容積為10L,適用于人造瑪瑙、人造大理石、人造花崗巖等高分子合成材料的攪拌,能抽掉漿料攪拌過程中產(chǎn)生的氣泡,又能很好的防止空氣二次混入漿內(nèi).第一章總體方案設計由設計內(nèi)容和要求可知,要設計的真空攪拌機的轉(zhuǎn)速在60r/min,功率1kw,因此用異步電動機提供動力,通過減速器來實現(xiàn)調(diào)速。由于采用攪拌桶轉(zhuǎn),而攪拌軸固定的形式,所以減速器置于機器的下方,通過圓柱蝸桿減速器來帶動攪拌桶轉(zhuǎn)動,為了便于攪拌桶裝料、卸料,攪拌桶要隨時可以拿下來,在攪拌桶與減速器之間加一個旋轉(zhuǎn)盤,旋轉(zhuǎn)盤與減速器通過鍵連接,與攪拌桶卡在一起,便于裝卸,由于要抽真空,因此攪拌桶必須密封,由捅蓋加密封圈實現(xiàn)密封,并且固定在攪拌軸,攪拌軸中空,外接真空泵,實現(xiàn)抽真空??傮w設計方案簡圖如下第二章傳動系統(tǒng)總體設計第一節(jié)傳動系統(tǒng)的選擇比較各種傳動系統(tǒng)的優(yōu)缺的 優(yōu)點缺點齒輪傳動承載能力和速度范圍大,傳動比較平穩(wěn),效率高,外廓尺寸小,工作平穩(wěn),壽命長。 制造及安裝精度要求高,價格教貴,不適用于傳動距離較遠的場合,傳動過程中有瞬時沖動的現(xiàn)象。 鏈傳動能保持準確的傳動比,傳動效率高,作用與軸上的徑向壓力小,結(jié)構(gòu)較為緊籌。只能用于通向的傳動,運轉(zhuǎn)不能保持瞬時傳動比,工作有噪音。帶傳動結(jié)構(gòu)簡單,傳動平穩(wěn),噪音較小,價格便宜。傳動比不恒定,壽命短本攪拌器體積比較小,結(jié)構(gòu)比較簡單,要求結(jié)構(gòu)要緊湊,如果選用帶傳動則機座體積過于龐大,而上面攪拌桶等體積小,不美觀而且浪費材料,真空攪拌機不需要像鏈傳動那樣保持精確的傳動比,而且鏈傳動工作時有噪音,因此使用齒輪傳動。由于總的傳動比要求不高,電機轉(zhuǎn)速為1390r/min,攪拌桶所需要的最終轉(zhuǎn)速為60轉(zhuǎn)r/min.減速比139060=23.17。采用一級齒輪傳動就可以滿足,由于需要改變傳動方向,所以采用圓柱蝸桿減速器。第二節(jié) 電動機的選則:選擇電動機的內(nèi)容包括:電動機類型、結(jié)構(gòu)型式、容量和轉(zhuǎn)速,要確定電動機具體型號。1、 選擇電動機類型和結(jié)構(gòu)型式電動機類型和結(jié)構(gòu)型式要根據(jù)電源(交流或直流)、工作條件(溫度、環(huán)境、空間尺寸等)和載荷特點(性質(zhì)、大小、啟動性能和過載情況)來選擇。沒有特殊要求時均選用交流電動機,其中以三相鼠籠式異步電動機用得最多。2、選擇電動機的容量標準電動機的容量由額定功率表示。所選電動機的額定功率應等于火燒大于工作要求的功率。容量小于工作要求,則不能保證工作機正常工作,或是電動機長期過載、發(fā)熱而過早損壞;容量過大,則增加成本,并且由于效率和功率因數(shù)過低造成浪費。 電動機的容量主要由運行時發(fā)熱條件限定,在不便或變化很小的載荷下長期連續(xù)運行的機械,只要電動機的負載不超過額定值,電動機便不會過熱,通常不必校驗發(fā)熱和起動力矩。所需電動機功率為 P=KW式中: P_工作機實際所需要的電動機輸出功率,KW;P-工作機所需輸入功率,KW;-電動機至工作機之間傳動裝置的總效率。工作機所需功率批P應由機器工作阻力和運動參數(shù)計算求得,例如P=KW 或P=KW式中: F工作機的阻力,N;v工作機的線速度,m/s;T工作機的阻力矩,Nm;n工作機的轉(zhuǎn)速,r/min;工作機的效率。總效率按下式計算:其中分別為傳動裝置中每一傳動副(齒輪、蝸桿、帶或鏈)、每對軸承、每個聯(lián)軸器的效率,選用此值時一般選用中間值。本攪拌機負載不高和生產(chǎn)工藝對電動機的啟動、制動、反轉(zhuǎn)、調(diào)速等沒有要求,因此可以選用普通三相異步電動機。電動機工作環(huán)境良好,不用考慮由于溫度、濕度、灰塵、雨水、瓦斯以及腐蝕和易爆炸氣體等原因,所采取的必要的保護方式本攪拌機體積小,要求功率低,低于1千瓦,要求轉(zhuǎn)速也不高。綜合以上幾點,選用Y系列三相異步電動機(JB3074-82)Y系列三相異步電動機是按照國際電工委員會(IEC)標準設計的,具有國際互換性的特點,其中Y系列(IP44)電動機為一般用途全封閉自扇冷式籠型三相異步電動機,具有防止灰塵、鐵屑或其他雜物侵入電機內(nèi)部之特點,B級絕緣,工作環(huán)境溫度不超過+40相對濕度不超過95%,海拔高度不超過1000米,額定電壓380伏,頻率50Hz。適用于無特殊需要的機械上。機床、泵、風機、運輸機、攪拌機、農(nóng)業(yè)機械上等。Y系列三相異步電動機完全符合所設計攪拌機的要求,且造價低,結(jié)構(gòu)簡單,便于日常維護。 Y系列三相異步電動機簡圖 根據(jù)轉(zhuǎn)速,功率的選擇電動機型號。選擇Y801-4,具體工作參數(shù)如下:額定功率0.55千瓦,滿載轉(zhuǎn)速1390r/min.質(zhì)量17千克.第三節(jié) 聯(lián)軸器的選擇(一)選擇聯(lián)軸器的類型的原則根據(jù)傳遞載荷的大小,軸轉(zhuǎn)速的高低,被連接力量部件的安裝,參考各聯(lián)軸器特性,選擇一種合用的聯(lián)軸器類型。具體選擇時可考慮以下幾點:1、 所需傳遞的扭矩的大小和性質(zhì)以及對緩沖減震功能的要求。例如,對大功率的重載傳動,可選用齒式聯(lián)軸器;對嚴重沖擊載荷或要求消除軸系扭轉(zhuǎn)振動的傳動,可選用輪胎式聯(lián)軸器等具有高彈性的聯(lián)軸器。2、 聯(lián)軸器的工作轉(zhuǎn)速高低和引起的離心力的大小。對于高速傳動軸,應選用平衡精度高的聯(lián)軸器,例如默片聯(lián)軸器等,而不宜選用存在偏心的滑塊聯(lián)軸器等。3、 兩軸相對位移的大小和方向。當安裝調(diào)整后,難以保持兩軸嚴格精確對中,或工作過程中兩軸將產(chǎn)生較大的附加相對位移時,應選用撓性聯(lián)軸器。例如當徑向位移較大時,可選用滑塊聯(lián)軸器,角位移較大或相交兩周的聯(lián)接可選用萬向聯(lián)軸器等。4、 聯(lián)軸器的可靠性和工作環(huán)境。通常由金屬元件制成的不需潤滑的聯(lián)軸器比較可靠;需要潤滑的聯(lián)軸器,其性能易受潤滑完善程度的影響,且可能污染環(huán)境。含有橡膠等非金屬元件的聯(lián)軸器對溫度、腐蝕性介質(zhì)及強光燈比較敏感,而且容易老化。5、 聯(lián)軸器的制造、安裝、維護和成本。在滿足使用性能的前提下,應選裝拆方便、維護簡單成本低的聯(lián)軸器。例如港性聯(lián)軸器不但結(jié)構(gòu)簡單,而且裝拆方便,可用于低速、剛性大的傳動軸。一般的非金屬彈性元件聯(lián)軸器,由于具有良好的綜合性能,廣泛適用于一般的中小功率傳動。常用的聯(lián)軸器多已標準化和規(guī)格化了。選用時,首先按工作條件選擇合適的類型,再按轉(zhuǎn)矩,軸徑和轉(zhuǎn)速選擇聯(lián)軸器的具體尺寸,必要時校核聯(lián)軸器內(nèi)薄弱件的承載能力。若無具體規(guī)范時,亦可參照推薦的主要尺寸定出全部的結(jié)構(gòu)尺寸,然后進行必要的校核計算。根據(jù)傳遞載荷的大小,軸轉(zhuǎn)速的高低,被連接兩部件的安裝精度等,各類聯(lián)軸器的特性,選擇一種合用的聯(lián)軸器類型。具體選擇時需考慮以下幾點:所需傳遞的轉(zhuǎn)矩大小和性質(zhì)以及對緩沖減振功能的要求。例如,對大功率的 重載傳動,可選用齒式聯(lián)軸器。聯(lián)軸器的工作轉(zhuǎn)速高低和引起的離心力大小。對于高速傳動軸,應選用平衡精度高的聯(lián)軸器。兩軸相對位移的大小和方向。當安裝和調(diào)整后,難以保持兩軸嚴格精度對中,或工作過程中兩軸將產(chǎn)生較大的附加相對位移時,應選用撓性聯(lián)軸器。聯(lián)軸器的可靠性和工作環(huán)境。通常由金屬元件制成的不需潤滑的聯(lián)軸器比較可靠;需要潤滑的聯(lián)軸器,其性能易受潤滑完善程度的影響,且可能污染環(huán)境。聯(lián)軸器的制造、安裝、維護和成本。在滿足使用性能的前提下,應選用裝拆方便、維護簡單、成本低的聯(lián)軸器。例如,剛性聯(lián)軸器不但結(jié)構(gòu)簡單,而且裝拆方便,可用于低速、剛性大的傳動軸。根據(jù)設計要求選擇彈性柱銷聯(lián)軸器。這種聯(lián)軸器結(jié)構(gòu)簡單,制造容易,裝拆更換彈性元件方便,有微量補償兩軸線偏移和緩沖吸振能力,主要用于載荷較平穩(wěn)。啟動頻繁,對緩沖要求不高的中,低速軸系運動,工作溫度為-20-+70。 2載荷計算 公稱轉(zhuǎn)矩 T=9550P/n 電機額定功率為0.55KW 滿載轉(zhuǎn)速為1390 rP=0.55kw n=1390r/minT=95500.55/1390Nm=3.778Nm 由表14-1查得K=1.7,故由公式計算轉(zhuǎn)矩為 Tca=kt=1.73.778Nm=6.42 Nm根據(jù)電動機的軸徑d=19mm,選擇HL1型彈性柱銷聯(lián)軸器。所選聯(lián)軸器如下圖所示:第四節(jié) 減速器的選擇本攪拌器體積比較小,結(jié)構(gòu)比較簡單,要求結(jié)構(gòu)要緊湊,如果選用帶傳動則機座體積過于龐大,而上面攪拌桶等體積小,不美觀而且浪費材料,真空攪拌機不需要像鏈傳動那樣保持精確的傳動比,而且鏈傳動工作時有噪音,因此使用齒輪傳動。由于總的傳動比要求不高,電機轉(zhuǎn)速為1390r/min,攪拌桶所需要的最終轉(zhuǎn)速為60轉(zhuǎn)r/min.減速比139060=23.17。采用一級齒輪傳動就可以滿足,由于需要改變傳動方向,所以采用圓柱蝸桿減速器。蝸桿減速器的特點是在外廓尺寸不大的情況下,可以獲得大的傳動比,工作平穩(wěn),噪聲較小,但效率較低。其中應用較廣的是單級蝸桿減速器,蝸桿配置方案的選取,亦視傳動裝置組合的方便與否而定。選擇時,應盡可能的選用下蝸桿的結(jié)構(gòu)。以為此時的潤滑和冷卻問題都較易解決,同時蝸桿軸承的潤滑也很方便。當蝸桿的圓周速度大于4-5m/s時,為了減少攪油和飛濺時損耗的功率,可采用上蝸桿結(jié)構(gòu)。根據(jù)機器要求直接選用標準的蝸桿,直接購買,不再另外設計。根據(jù)標準Q/ZB125-73介紹此為一級傳動的WD(蝸桿下置)WS(蝸桿上置)型阿基米德圓柱蝸桿減速器,其適范圍:蝸桿嚙合處滑動速度不大于7.5m/s:蝸桿轉(zhuǎn)速不超過157rad/s(1500rpm);工作的環(huán)境溫度為-40-+40;可用于正反兩向運動.電機轉(zhuǎn)速為1390r/min,所需要的轉(zhuǎn)速為60轉(zhuǎn)r/min.傳動比為23.17,查QQ/ZB125-73選用傳動比23.5,查到中心距80mm.1. 已知:中心距80 mm,模數(shù)4,速比23.5,由機械手冊查表q=10,m=4, 中心距80 mm.中心距:a=0.5m(q+Z2+2x2)=0.54(q+Z2)=80(mm)變位系數(shù): X=a/m-(d1+ d2)/2m= 0.5 蝸輪齒數(shù)發(fā)生變化: X=(Z2- Z2)/2Z2=32導程: m Z1=25.12(mm)蝸桿分度圓直徑: d1= qm=40(mm)蝸桿齒頂圓直徑:軸向和法向壓力角(齒型角)取標準 =20蝸桿軸向齒矩: m=12.56(mm)蝸桿齒頂圓直徑: = d1+2m=48(mm)蝸桿齒根圓直徑: = d1-2=-2(mc)=30(mm)蝸桿頂隙: c= cm=1漸開線蝸桿基圓直徑: = d1 tan/ tanb=19.05(mm)蝸桿齒頂圓高: 1=m=4蝸桿齒根圓高: =(c)=5(mm)蝸桿齒高: =1=9(mm)d1= d12x2 m=36(mm)= d1+2m=44(mm)= d1-2=-2(mc)=26(mm)蝸桿齒寬: (80.06 Z2)m=39.44(mm)取齒寬40(mm) 2由GB1356-88規(guī)定: =2,=3蝸輪分度圓: d2=mZ2=431=124(mm)蝸輪喉圓直徑: = d2=128(mm)蝸輪齒根圓直徑: = d2-=110(mm)蝸輪齒頂高: =0.5(- d2)=2(mm)蝸輪齒根高: =0.5(d2-)=7(mm)蝸輪齒高: =9(mm)蝸輪咽喉母圓直徑: =16(mm)蝸輪寬度: B=0.75=36(mm) B取36(mm)蝸輪齒寬角: =2=128蝸桿軸向齒厚: m=6.28(mm)蝸桿法向齒厚: =6.16(mm)蝸桿節(jié)圓直徑: d1= d12x2 m=36(mm)蝸輪節(jié)圓直徑: =124(mm) 1.5 m=134(mm) 取134(mm) 蝸輪蝸桿簡圖 2. 蝸輪蝸桿的校核1 選擇蝸桿傳動根據(jù)GB/T10085-1988的推薦,采用漸開線蝸桿(ZI)。2 選擇材料考慮蝸桿傳動功率不大,故蝸桿用45鋼淬火;因速度V=0.35m/s2m/s.所以蝸輪用鑄鋁鐵青銅金屬模鑄造。3按齒面接觸疲勞強度進行設計由H=ZEZP(1)確定作用在蝸輪上的轉(zhuǎn)矩T2Z1=2,取效率=0.8則 T2=9550000=68574.3N.mm(2)確定載荷系數(shù)K 因工作載荷穩(wěn)定故取KB=1,由機械設計P250表115取KA=1.15;由于沖擊不大,取動載荷系數(shù)KV=1.05則 K=KA*KB*KV=1.15*1.05*1=1.21(3)確定彈性系數(shù)ZE 由機械設計課程設計手冊可得ZE=105MPa(4)確定接觸系數(shù)ZP有d1/a=36/80=0.45可查的ZP=2.7(5)確定許用接觸H由VS=0.58m/S,蝸桿為45鋼,蝸輪為鑄鋁鐵青銅查表可知H=240MPa.H=1052.7=113.4MPaH4校核齒根彎曲疲勞強度=YFa2Y當量齒數(shù)Zv2=34.04根據(jù)x2=-0.5,Zv2=34.04,從圖11-9種可得YFa2=3.1螺旋角系數(shù)Y=1-=0.9192查表11-8可得許用彎曲應力=90MPa. =3.10.9192MPa=20.25MPa所以彎曲強度滿足5 精度等級公差和表面粗糙度的確定從略7熱平衡核酸(從略).第五節(jié) 旋轉(zhuǎn)盤的設計為了保證動力的傳遞,在減速器和攪拌桶之間要設計一個機構(gòu)來傳遞運動和轉(zhuǎn)距,因此設計一個旋轉(zhuǎn)盤來帶動攪拌桶旋轉(zhuǎn)。旋轉(zhuǎn)盤就相當于一個傳動軸。1.軸的結(jié)構(gòu)設計包括定出軸合理外形和全部結(jié)構(gòu)設計。2.軸的結(jié)構(gòu)主要取決于以下因素:軸在機器中的按照位置及形勢;軸上安裝的零件的類型、尺寸、數(shù)量以及和軸連接的方法;載荷的性質(zhì)、大小、方向及分布情況、軸的加工工藝等。由于影響軸的結(jié)構(gòu)的因素較多,且其結(jié)構(gòu)形式又要隨著具體情況的不同而異,所以軸沒有標準的結(jié)構(gòu)形式。設計時,必須針對不同情況進行具體的分析。但是,不論何種具體條件,軸的結(jié)構(gòu)都應滿足:軸和安裝在軸上的零件要有準確的工作位置;軸上的零件應便于裝坼和調(diào)整;周應具有良好的制造工藝性等。3. 擬訂軸上零件的裝配方案是進行軸的結(jié)構(gòu)設計的前提,它取決著軸的基本形式。所謂裝配方案,就是預定出軸上主要零件的裝配方向,順序和相互關系。軸上零件的定位。4.為了防止軸上零件受力十發(fā)生沿軸向或周向的相對運動,軸上零件除了有游動或空轉(zhuǎn)的要求者外,都必須進行軸向定位和周向定位,以保證其準確的工作位置。具體結(jié)構(gòu)如下圖所示. 旋轉(zhuǎn)盤采用的是鑄件的下端是一個軸套,通過鍵套在減速器的低速端,在旋轉(zhuǎn)盤的上端有4個孔,可以和攪拌桶下端的4個突起配合,傳遞動力。1首先確定軸的傳遞功率,轉(zhuǎn)矩和轉(zhuǎn)速 P=0.550.80.8=0.352kw n=1390r/min23.5=59r/minT=9550=2.軸校核按彎扭合成強度條件計算扭轉(zhuǎn)強度計算轉(zhuǎn)矩T=56.98Nm扭轉(zhuǎn)切應力=Nd=126=30.44mm所以符合要求第六節(jié) 軸上鍵槽及鍵選擇鍵的選擇包括類型選擇和尺寸選擇兩個方面。鍵的類型應根據(jù)鍵聯(lián)的結(jié)構(gòu)點、使用要求和工作條件來選擇;鍵的尺寸則按符合標準規(guī)格和強度要求來決定。根據(jù)設計的要求在本次設計中,均采用平鍵聯(lián)接。鍵的兩側(cè)面是工作表面,工作時,靠鍵同鍵槽側(cè)面的擠壓來傳遞扭矩。鍵的表面和軸套的鍵槽底面間留有間隙。平鍵聯(lián)接具有結(jié)構(gòu)簡單、裝卸方便、對中性好等優(yōu)點,因而得到廣泛的應用。這種鍵不能承受軸向力,因而對軸上的零件不能起到軸向固定的作用。 旋轉(zhuǎn)盤與轉(zhuǎn)子和軸的周向定位均采用半圓平鍵聯(lián)結(jié)。根據(jù)軸1的直徑,查手冊得半圓平鍵的截面尺寸為: p= =31.22 MPa1020粗加工表面比較精密的一級,應用比較廣泛,如軸端面、倒角、穿螺紋孔等。510半精加工面,支架,箱體,離合器,凸輪側(cè)面等非接觸面的自由表面與螺紋頭接觸的表面,所有軸的退刀槽。2.55半精加工面,箱體,支架,蓋面套筒等和其它零件的表面。1.252.5基面及表面要求較高的表面,中型機床工作臺面,箱體的箱蓋和箱座的結(jié)合面,低速轉(zhuǎn)動的軸頸。設計心得與致謝辭畢業(yè)設計是培養(yǎng)學生獨立思考和科學工作方法的實踐過程,是學生四年所學東西的綜合性訓練和培養(yǎng)學生工作能力與創(chuàng)造能力的一次重要實踐活動。畢業(yè)設計正式將自己所學的專業(yè)知識和具體實際機械結(jié)合起來,從而能增強學生解決實際問題的能力。我所設計真空攪拌機是生產(chǎn)人造瑪瑙、人造大理石、花崗巖等樹脂合成裝飾材料的專用設備。該機結(jié)構(gòu)簡單,操作維修方便,能在抽真空攪拌運轉(zhuǎn)過程中,避免空氣進入桶內(nèi),減少物料攪拌時間和物料中的氣泡缺陷,提高產(chǎn)品的強度,增強產(chǎn)品的耐水性的耐磨性。 在短短的兩個月內(nèi),作為一名沒有實際生產(chǎn)經(jīng)驗的學生,要把設計作的成熟是不可能的。因此在設計中我進了最大的努力,力求做的更好,但是設計中仍會不可避免的出現(xiàn)錯誤。雖然出現(xiàn)了很多錯誤,然而設計中,在修改錯誤中,我體會到了掌握知識的快樂,收獲的快樂,相互交流的快樂。每出現(xiàn)一處錯誤,也就是自己對一部分知識的不理解,或理解錯誤,在導師的耐心講解下,改正了錯誤,留下深刻的印象,以后再犯的機會就很小,整個的畢業(yè)設計,幾乎涉及到了大學4年學到的所有知識,也是對專業(yè)知識進行了較為全面的復習。通過設計,我們對設計的一整套程序有了較為深刻得體會。并領會了作為設計人員應具有的素質(zhì)。激勵我們繼續(xù)去學習。三個多月的畢業(yè)設計很快過去了,整個設計對我來說是對大學五年所學知識的一次綜合和檢測,是我們將理論知識運用到實際中去的又一次最好的機會。在我的論文工作期間,得到了許多老師、同學的幫助,沒有他們無私的幫助,我的論文是難以完成的,在此,由衷地表示感謝。在這設計過程中從查閱資料,到設計方案的確定,再到寫作方案,實際設計等,每一個環(huán)節(jié)都滲透著我們辛勤的汗水,都少不了一番的冥思苦想和努力工作,但是更離不開老師們的細心指導和不吝指教。在這里我要特別感謝我的指導老師:馬正先老師,感謝他在審題、構(gòu)思、設計工作中給予我的幫助和支持,如果沒有他們的指導,就可能沒有我設計的產(chǎn)生。特別給我留下深刻印象的是淵博的學識、嚴謹?shù)闹螌W態(tài)度、實事求是的作風和巨細入微的風范,并將成為我的終生受益的精神財富。在百忙之中,老師們還是抽出大量的時間給我指點迷津,在老師們的指點下使我整個設計思路和方法清晰、準確,順利的完成了畢業(yè)設計。此外,更重要是從老師們那兒學到了工作和學習的有效方法,學到了更多在課堂上學不到的東西,動手實踐使我受益非淺,為以后的工作和學習打下堅實的基礎。在此對老師們表示忠心的感謝!此外還要感謝同學在設計工作中給予的真誠共同合作,也感謝各位師兄弟無私的幫助。我也要感謝在讀書期間給予我許多幫助的眾多老師。感謝他們在我生活、學習上無微不至的關心和照顧。參 考 文 獻1機械制造裝備設計馮辛安,黃玉美,杜君文北京:機械工業(yè)出版社,19992機械設計課程設計手冊吳宗澤,羅圣國第二版,北京:高等教育出版社,19993機械設計手冊(上冊)機械設計手冊聯(lián)合編寫組第二版,北京:化學工業(yè)出版社,1987年8月4機械設計手冊(中冊)機械設計手冊聯(lián)合編寫組第二版,北京:化學工業(yè)出版社,1987年8月5機械設計手冊(下冊)機械設計手冊聯(lián)合編寫組第二版,北京:化學工業(yè)出版社,1987年8月6、機械設計手冊 成大先 主編 姜勇 王德夫 長順 韓學拴 副主編 化學工業(yè)出版社 7機械制圖大連理工大學工程畫教研室組編第四版,北京:高等教育出版社,1995年5月8機械設計紀名剛第六版北京:高等教育出版社,19999、機械設計 濮良貴 紀名剛 主編 高等教育出版社 第七版10機械零件設計手冊葛志淇北京:冶金工業(yè)出版社,199411機械零件設計手冊楊黎明北京:國防工業(yè)出版社,198712機械零件設計手冊成大先北京;化學工業(yè)出版社,199713互換性和技術測量謝鐵邦 李柱 河南理工大學萬方科技學院本科畢業(yè)論文附錄:外文資料與中文翻譯外文資料:Comparing mixing performance of uniaxial and biaxial bin blenders Amit Mehrotra and Fernando J. MuzzioDepartment of Chemical and Biochemical Engineering, Rutgers University, Piscataway, NJ, 08855, United StatesReceived 17 February 2009; revised 30 May 2009; accepted 14 June 2009. Available online 27 June 2009.AbstractThe dynamics involved in powder mixing remains a topic of interest for many researchers; however the theory still remains underdeveloped. Most of the mixers are still designed and scaled up on empirical basis. In many industries, including pharmaceutical, the majority of blending is performed using “tumbling mixers”. Tumbling mixers are hollow containers which are partially loaded with materials and rotated for some number of revolutions. Some common examples include horizontal drum mixers, v- blenders, double cone blenders and bin blenders. In all these mixers while homogenization in the direction of rotation is fast, mediated by a convective mixing process, mixing in the horizontal (axial) direction, driven by a dispersive process, is often much slower. In this paper, we experimentally investigate a new tumbling mixer that rotates with respect to two axes: a horizontal axis (tumbling motion), and a central symmetry axis (spinning motion). A detailed study is conducted on mixing performance of powders and the effect of critical fundamental parameters including blender geometry, speed, fill level, presence of baffles, loading pattern, and axis of rotation. In this work Acetaminophen is used as the active pharmaceutical ingredient and the formulation contains commonly used excipients such as Avicel and Lactose. The mixing efficiency is characterized by extracting samples after pre-determined number of revolutions, and analyzing them using Near Infrared Spectroscopy to determine compositional distribution. Results show the importance of process variables including the axis of rotation on homogeneity of powder blends.Graphical abstractThe dynamics involved in powder mixing remains a topic of interest for many researchers; however the theory still remains underdeveloped. Most of the mixers are still designed and scaled up on empirical basis. In many industries, including pharmaceutical, the majority of blending is performed using “tumbling mixers”. In all these mixers while homogenization in the direction of rotation is fast, mediated by a convective mixing process, mixing in the horizontal (axial) direction, driven by a dispersive process, is often much slower. In this paper, we experimentally investigate a new tumbling mixer that rotates with respect to two axes: a horizontal axis (tumbling motion), and a central symmetry axis (spinning motion).Keywords:Powder mixing ; Cohesion; Blender ; Mixer; Relative standard deviation; NIR; AcetaminophenArticle Outline1.Introduction2.Materials and methods2.1. Near infrared spectroscopy2.2. Bin blenders used in this study: uni-axial blender (Blender 1), bi-axial blender (Blender 2)2.3. Experimental method3.Results4.ConclusionReferences1. IntroductionParticle blending is a required step in a variety of applications spanning the ceramic, food, glass, metallurgical, polymers, and pharmaceuticals industries. Despite the long history of dry solids mixing (or perhaps because of it), comparatively little is known of the mechanisms involved 1, 2 and 3. A common type of batch industrial mixer is the tumbling blender, where grains flow by a combination of gravity and vessel rotation. Although the tumbling blender is a very common device, mixing and segregation mechanisms in these devices are not fully understood and the design of blending equipment is largely based on empirical methods. Tumblers are the most common batch mixers in industry, and also find use in myriad of application as dryers, kilns, coaters, mills and granulators 4, 5, 6, 7 and 8. While free-flowing materials in rotating drums have been extensively studied 9 and 10, cohesive granular flows in these systems are still not completely understood. Little is known about the effect of fundamental parameters such as blender geometry, speed, fill level, presence of baffles, loading pattern and axis of rotation on mixing performance of cohesive powders or the scaling requirements of the devices. However, conventional tumblers, rotating around a horizontal axis, all share an important characteristic: while homogenization in the direction of rotation is fast, mediated by a convective mixing process, mixing in the horizontal (axial) direction, driven by a dispersive process, is often much slower.In this paper, we experimentally investigate a new tumbling mixer that rotates with respect to two axes: a horizontal axis (tumbling motion), and a central symmetry axis (spinning motion). We examine the effects of fill level, mixing time, loading pattern and axis of rotation on the mixing performance of a free-flowing matrix of Fast Flo lactose and Avicel 102, containing a moderately cohesive API, micronized Acetaminophen. We use extensive sampling to characterize mixing by tracking the evolution of Acetaminophen homogeneity using a Near Infrared spectroscopy detection method. After materials and methods are described in Section 2, results are presented in Section 3, followed by conclusions and recommendations, which are presented in Section 4.2. Materials and methodsThe materials used in the study are listed in Table 1, along with their size and morphology. Acetaminophen is blended with commonly used excipients and is used as a tracer to evaluate the degree of homogeneity achieved as a function of number of revolutions. Acetaminophen is one of the drugs most widely used in mixing studies, and Avicel and Lactose are commonly used pharmaceutical excipients. In the interest of brevity their SEM images are not included in this paper, but can be found in “Handbook of Pharmaceutical excipients”.2.1. Near infrared spectroscopyAcetaminophen homogeneity was quantified using near infrared spectroscopy. A calibration curve was constructed for a powder mixture containing (in average) 35% avicel PH 102, 62% lactose and 3% acetaminophen. Near infrared (NIR) spectroscopy can be a useful tool to characterize acetaminophen. Samples are prepared by keeping the ratio of Avicel to lactose randomized in order to minimize effects of imperfect blending of excipients during the actual experiments on the accuracy of the results. The Rapid Content Analyzer instrument manufactured by FOSS NIR Systems (Silver Spring, MD) and Vision software (version 2.1) is used for the analysis. The samples are prepared by weighing 1 g of mixture into separate optical scintillation vials; (Kimble Glass Inc. Vineland, NJ) using a balance with an accuracy of 0.01 mg. Near-IR spectra are collected by scanning in the range 11162482 nm in the reflectance mode. Partial least square (PLS) regression is used in calibration model development using the second derivative mathematical pretreatment to minimize the particle size effects. As shown in Fig. 1, excellent agreement is achieved between the calibrated and predicted values. Fig. 1.Fig. 1. Near Infrared (NIR) spectroscopy validation curve. The equation used to predict acetaminophen concentration is validated by testing samples with known amounts of acetaminophen concentration. The y axis represents the concentration calculated from the equation and the x axis represents the actual concentration. Thus a perfectly straight line at 45 would represent the best calibration model. Each point on the graph represents a single sample. The concentration of acetaminophen examined here ranges from 0 to 8%.2.2. Bin blenders used in this study: uni-axial blender (Blender 1), bi-axial blender (Blender 2)Due to its widespread use, a cylindrical blender 1 with a capacity of 30 L is chosen as a reference blender in the study. As shown in Fig. 2, this blender has a circular cross section and tapers at the bottom. It can be used with or without baffles, which are mounted on a removable lid. In this study all the experiments are conducted without the use of baffles. Mixing performance in this device is used to provide a base-line for evaluating the mixing performance of a newly developed blender 2 with a capacity of 40 L, which is also cylindrical, in order to determine the effect of dual axis of rotation on mixing performance. The blender shown in Fig. 2(b) has two axis of rotation. The spinning rate of precession relative to the central axis of symmetry is geared to be half of that of the rate of rotation around the horizontal axis. Fig. 2.Fig. 2. Pictorial representation of (a) bin blender 1 and (b) bin blender 2 showing the corresponding axis of rotation.2.3. Experimental methodTwo types of initial powder loading used in the experiments: topbottom loading and sideloading, which are schematically represented in Fig. 3. To avoid agglomeration, the API, acetaminophen, was delumped prior to loading it into the blender by passing it through a 35 mesh screen. In order to characterize mixing performance, a groove sampler was used to extract samples from the blenders at 7.5, 15, 30, 60, 120 revolutions. The thief was carefully inserted in the bin, and a core was extracted at each point of insertion (each “stab”) minimizing perturbation to the powder bed remaining in the blender. Approximately 7 samples are taken from each thief stab, and a total of five stabs are used at each sampling time, as shown in Fig. 4 so a total of 35 samples are taken at each sampling point. Fig. 3.Fig. 3. Schematic of the loading pattern used in the study. In topbottom loading, Avicel is loaded first into the blender followed by Lactose on top of it and finally Acetaminophen is uniformly sieved over. In sideside loading avicel is placed at the bottom and then Acetaminophen is only sieved only in half part of the blender and is sandwiched between lactose and Avicel. Fig. 4.Fig. 4. (a) Thief sampler (b) top view of the sampling position scheme.The experimental plan used in this study is as follows: Fill level: blender 160% Fill level: blender 260%, 70%, 80% Loading pattern: blender 1 sideside loading, topbottom loading Loading pattern: blender 2 sideside loading, topbottom loading Speed: blender 115 rpm, 20 rpm, 25 rpm Speed: blender 2 rotational/spinning:15/7.5 rpm, 20/10 rpm, 30/15 rpm Sampling time: blender 1, blender 27.5, 15, 30, 60, 120 revolutions3. ResultsThe homogeneity index used is the RSD, where C is the concentration of each individual sample, C_ is the average concentration of all samples and n is the total number of samples obtained at a given sampling time.We examine the effect of fill level on mixing performance. Previously there have been studies on the effect of fill level in the Bohle bin blender, Gallay bin blender and V- blender and double cone blender 11, 12 and 13. All the aforementioned blenders have only one axis of rotation, therefore the objective of this study is to examine how dual axis impact mixing performances at high fill levels. To avoid repetition, studies for fill level are not conducted for bin blender 1. Results available from a previous study using MgSt as a tracer showed that mixing in a uni-axial blender slowed down quite dramatically as the fill level exceeded 70%. Moreover, results for acetaminophen can be assumed to be similar to those obtained in previous work by Muzzio et al. 11 and 13, for a single axis rectangular bin blender 11, which have shown that even after few hundred revolutions homogeneity achieved with a 80% fill level is very poor as compared to 60% fill level.To examine the effect of fill level in a dual axis blender, experiments were performed in blender 2 with the top-bottom loading pattern for a rotational speed of 15 rpm and with spinning speed of 7.5 rpm. The fill levels examined are 60%, 70% and 80% respectively and samples are taken after 7.5, 15, 30, 60, 120 revolutions. Typical results are shown in Fig. 5, which shows the RSD vs. number of blender revolutions. As expected for non-agglomerating materials, the curves show a rapidly decaying region. The slope of the curves in this region, in semi-logarithmic coordinates, is used to define the mixing rate. The curves then level off to a plateau that indicates the maximum degree of homogeneity that is achievable in the blender for a give material. Fig. 5.Fig. 5. Mixing curves for different fill levels in blender 2. The RSD of acetaminophen is plotted as a function of number of revolutions. The loading pattern in top-bottom and the blender rotational speed is 15 rpm with spinning speed of 7.5 rpm.Similar to previous studies with other tumbling blenders we observe that blending performance is adversely affected by increasing fill levels. As shown in Fig. 5, the curve for 80% fill performs more poorly than those for 60% and 70% fill; as fill level increases, RSD curves decay more slowly, signifying a slower mixing process. However, the effect is not as pronounced as in other bin blenders and after about only 100 revolutions, the same plateau (the same asymptotic blend homogeneity) is achieved for all three fill levels.Next, the effect of rotational speed is investigated in the blender 1 with one axis of rotation and is compared to the blender 2 with dual rotation axis. Experiments were conducted for both blenders with top-bottom and side-side loading. Experiments were performed at 60% fill level and the rotation speeds considered for blender 1 are 15 rpm, 20 rpm and 25 rpm respectively. As shown in Fig. 6 and Fig. 7, when plotted as a function of blender revolutions, there is not much of an effect of rotation speed on the homogeneity index (RSD) of acetaminophen at 60% fill level. It is observed that mixing performance at 20 rpm and 25 rpm is slightly better than at 15 rpm, however the differences in the performance of the blender under different speeds are probably too small to be significant. RSD curves decay with the same slope, indicating similar mixing rates. In the study reported here, the fill level is only 60%, and all the rotational speeds are enough to achieve homogenization. The aforementioned studies were conducted at 85% fill level. For such a high fill level, at low speeds, a stagnant core is known to occur at the center of many blenders, requiring higher shear stress per unit volume to achieve homogenization. Moreover, the flow properties of MgSt are known to be strongly different than those of most materials, and are known to have a deep impact on the flow properties of the mixture as a whole. Furthermore, MgSt is famously known to be a shear sensitive material. Thus an expectation that lubricated and unlubricated blends would show similar behavior with respect to shear is probably unwarranted. Fig. 6.Fig. 6. Mixing curves for top-bottom loading experiments with 60% fill level. RSD is plotted as a function of number of revolutions. Dotted lines correspond to experiments in the blender 1, while solid lines represent data points from the blender 2. Fig. 7.Fig. 7. curves for sideside loading experiments with 60% fill level. RSD is plotted as a function of number of revolutions. Dotted lines correspond to experiments in the while solid lines represent data points from the 2.Subsequently, experiments were performed using the blender 2 at three rotation speeds: 15 rpm, 20 rpm and 30 rpm, and as explained before, the corresponding spinning speeds were 7.5 rpm, 10 rpm and 15 rpm. Fill level considered for both side-side and top-bottom loading was 60%.Again, it was observed that varying rotation and spinning speeds did not make much difference in mixing rate. As shown in Fig. 6 and Fig. 7, mixing curves for blender 2 vary only slightly with rotation speed. For the top-bottom loading pattern it appears that mixing improves slightly when rotation speed is increased (the plateau is slightly lower for higher rotation speeds, indicating an improvement in the levels of asymptotic homogeneity), but no significant changes with speed are observed in side-side loading pattern.The blending performance of both blenders is compared at different rotation speeds for both side-side and top-bottom loading patterns. To make a fair comparison, the fill level was kept as 60% for both blenders, a condition for which both blenders achieve effective mixing at long enough times. Due to geometric similarity of the two blenders, this comparison help evaluate the effect of spin (rotation with respect to the central symmetry axis) on mixing performance. As shown in Fig. 6, the mixing curves for the blender 2 lie below those for the blender 1 for each rotation rate, indicating faster mixing. Note that the final RSD asymptote reached for both blenders is also different, with the blender 2 showing a lower asymptote (better final mixed state, presumably due to a lesser effect of the slow mixing mode in the horizontal direction) than blender 1.Similar results were obtained for the side-side loading pattern, as displayed in Fig. 7. The RSD curves for the blender 1 for all the three rotation rates lie above the blender 2. It is therefore confirmed that spinning a blender in direction perpendicular to the rotation axis helps in enhancing mixture homogeneity; however, for the materials examined here, the rotation rate does not have much effect on mixing performance. Finally, a comparison is made between the two loading patterns for both blenders. Again, to achieve a fair comparison, all experiments are performed at 15 rpm and 60% fill level. As evident in Fig. 8, in both blenders topbottom loading gives a more rapid decay of the RSD, indicating faster homogenization as compared to sideside loading pattern. However, for both loading modes, blender 2 achieves faster homogenization. Fig. 8.Fig. 8. Comparison between the mixing curves of the blender 2 and the blender 1 for topbottom and sideside loading pattern. Dotted lines correspond to experiments in the blender 1, while solid lines represent data points from the blender 2. Experiments are performed at 15 rpm with 60% fill level.As reported in previous studies, all the RSD curves in this paper exhibit a common trend with respect to time, characterized by an initial period of rapid homogenization due to convective mixing, followed by a period of much slower homogenization typically controlled by dispersion or shear. This trend is shown schematically in Fig. 9. The first regime is a fast exponential decay and the second one is a slow exponential asymptote to a limiting plateau. The first part represents a rapid reduction in heterogeneity driven by the bulk flow (convection); the slope of the RSD curve, in semi-logarithmic coordinates, is the convective mixing rate. The second part is driven by individual particle motion (dispersion) or by the slow erosion of API agglomerates due to shear. Fig. 9.Fig. 9. A typical mixing plot, with RSD plotted against number of revolutions. The two solid lines emphasize on the two distinctive mixing regimes.When only one mixing mechanism is present (a situation that can be achieved by careful control of the initial loading pattern), a simple mass-transfer model, represented in Eq. (1) can be used, as in past studies 14, to capture the evolution of the RSD in powder systems. In this model, an exponential curve decaying towards a plateau is fitted to the mixing curves, where is the standard deviation, the final standard deviation, A is an integration constant, signifies t
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