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I天津机电职业技术学院毕业设计

天津机电职业技术学院

毕业综合实践报告

学 生:

班 级: 08级机电一体化四班 学 号: 200821106

题 目: 2m3电加热搅拌釜设计和温度控制系统设计

指导教师: 王煦伟

完成时间:2010年12月24日

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II天津机电职业技术学院毕业设计

摘 要

机械搅拌反应器(也称为搅拌釜式反应器)广泛应用在石油化工等行业中,如工艺过程的混合(如调和、乳化、分散、固体悬浮等),传质(如溶解、气体吸收、结晶、萃取等),传热(如在搅拌容器内加热、冷却等)。搅拌反应釜是由搅拌容器和搅拌机两大部分组成,搅拌机和搅拌容器。搅拌机又包括搅拌器和传动装置。

在此次毕业设计中,我在导师的指导下,进行了2立方米电加热式搅拌釜及其温度控制系统设计。容器内物料为液体炸药, 采用电加热器加热,夹套传热。由于物料黏度较高, 选用直叶圆盘涡轮式搅拌器。此计算说明书对我所设计的搅拌釜各部分进行了详细地计算说明。其中主要包括容器总体尺寸确定即筒体与封头计算、搅拌功率及搅拌强度计算包括搅拌器选型及强度校核、搅拌轴机械计算包括轴径确定及强度校核、搅拌釜传动装置选型设计、传热结构计算及校核、设备管口确定及补强计算、设备温度控制系统设计。

关键词:容器;传热夹套;搅拌设备;温度控制系统

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III天津机电职业技术学院毕业设计

Abstract

Dgitated device are widely used in many industry processes,Such as material mixture (e.x.equalization,emulsification,scatter

operation),mass

transport

process

(e.x.

solution,crystallization),heat transfer process (e.x. heating,cooling) and so on.There are two main parts in an agitating device,an agitator and a vessel.An agitator include stirrer and driving device.

In the graduate design I finished a 2 cubic meters electrically heated agitated tank ang it’s temperature control system with the help of my teacher.The material in the vessel is liquid explosive.The jacket is heated by electric heater and then it transfers the heat to the material in the vessel.Because the viscosity of liquid explosive is high,I choose the flat disk turbine agitator.In this calculation sheet,I calculate the size of the vessel,the heat jacket,the mixer shaft,and the agitator,the drive system,the heat transfer equipment ad the temperature control system..

Key Words:Vessel;Heat jacket;Agitator device;Temperature control system

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IV天津机电职业技术学院毕业设计

目 录

摘 要 ··········································································································································· II Abstract ············································································································································ III 第1章 釜体总体尺寸计算 ············································································································ 1

1.1 初步计算筒体直径Di ······································································································ 1 1.2 确定筒体高度H ··············································································································· 1 1.3 计算液面高度Hl ·············································································································· 2 1.4 封头计算 ··························································································································· 2

1.4.1 封头厚度计算(内压工况) ·············································································· 3 1.4.2 封头厚度(外压工况) ······················································································· 3 1.5 圆筒计算 ··························································································································· 3

1.5.1 内压圆筒计算厚度 ······························································································· 4 1.5.2 外压圆筒计算厚度 ······························································································· 4 1.6 夹套计算 ··························································································································· 4 1.7 液压试验状态稳定校核 ·································································································· 5 第2章 搅拌功率计算 ···················································································································· 6

2.1 搅拌器选型及尺寸确定 ·································································································· 6 2.2 搅拌功率计算 ··················································································································· 7

2.2.1 每一个搅拌器的搅拌功率准数P01、P02计算 ················································· 7 2.2.2 双层搅拌器总功率准数P0C的计算 ··································································· 8 2.2.3 功率准数校正总系数k的确定 ·········································································· 8 2.2.4 多层搅拌器总功率(Pc) ·················································································· 8

第3章 搅拌强度计算 ·················································································································· 8

3.1 搅拌器设计功率 ··············································································································· 8

3.1.1 电动机的计算功率和额定功率 ·········································································· 8 3.1.2 每层搅拌器的设计功率Pq(Z=2) ································································· 9 3.1.3 搅拌器每个桨叶强度计算用设计功率 ······························································ 9 3.2 搅拌器桨叶材料的许用应力 ·························································································· 9

3.2.1 弯曲许用应力 ········································································································ 9 3.3 圆盘涡轮式搅拌器强度计算 ························································································ 10

3.3.1 弯矩MI ················································································································ 10 3.3.2 抗弯截面模数WI(I—I断面处) ·································································· 10

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V天津机电职业技术学院毕业设计

3.3.3 弯曲应力σI ········································································································· 10

第4章 搅拌轴机械计算 ·············································································································· 11

4.1 搅拌容器主要尺寸计算及搅拌器层数确定 ······························································· 11 4.2 搅拌轴机械计算 ············································································································· 12

4.2.1 按扭转变形控制的轴径d1的计算 ··································································· 12 4.2.2 搅拌轴及搅拌器(包括附件)有效质量的计算 ··········································· 13 4.2.3 搅拌轴临界转速计算 ························································································· 14 4.2.4 按强度计算搅拌轴的轴径d2 ············································································ 15 4.2.5 搅拌轴径向位移计算及按其在轴封处的允许径向位移验算轴径 ·············· 19 4.2.6 搅拌轴轴径的最后确定 ····················································································· 21 4.3 搅拌器与搅拌轴的连接 ································································································ 21

4.3.1 连接强度计算 ······································································································ 21

第5章 搅拌釜传动装置 ·············································································································· 21

5.1 传动装置的组成 ············································································································· 21 5.2 传动装置的标准零部件 ································································································ 21

5.2.1 凸缘法兰 ·············································································································· 21 5.2.2 安装底盖 ·············································································································· 22 5.2.3 机架 ······················································································································ 22 5.2.4 机械密封 ·············································································································· 22 5.2.5 减速机选型及说明 ····························································································· 22 5.2.6 电动机选型及说明 ····························································································· 22

第6章 搅拌釜传热结构及强度计算 ······················································································· 23

6.1 夹套尺寸 ························································································································· 23 6.2 夹套与容器筒体连接处结构(图6.1) ····································································· 23 6.3 夹套封头与容器封头的连接结构(图6.2) ····························································· 24 6.4 夹套容器的附件结构 ···································································································· 24 6.5 U形夹套容器的强度计算 ····························································································· 24

6.5.1 U形夹套容器的强度计算公式适用条件 ························································· 24 6.5.2 夹套容器强度计算 ····························································································· 25 6.6 支座选型及计算 ············································································································· 27

6.6.1 支座选型 ·············································································································· 27 6.6.2 支座实际承受载荷的计算 ················································································· 28

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VI天津机电职业技术学院毕业设计

6.6.3 校核支座反力对容器壁作用的外力矩M0 ····················································· 28

第7章 设备管口 ························································································································ 30

7.1 设备所有管口名称 ········································································································· 30 7.2 各管口选型 ····················································································································· 30

7.2.1 人孔选型 ·············································································································· 30 7.2.2 补强计算 ·············································································································· 30 7.2.3 试镜 ······················································································································ 32 7.2.4 其它管口 ·············································································································· 32

第8 温度控制系统设计 ··············································································································· 33

8.1 电加热器功率计算 ········································································································· 33 8.2 温度控制系统组成 ········································································································· 34

8.2.1 控制系统的简单介绍 ························································································· 34 8.2.2 控制系统说明 ······································································································ 35

结 论 ············································································································································· 37 参考文献 ········································································································································· 38 致 谢 ··········································································································································· 39

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1天津机电职业技术学院毕业设计

第1章 釜体总体尺寸计算

该搅拌釜有效容积2立方米,采用夹套传热,加热方式为电加热。搅拌釜及夹套封头采用标准椭圆形封头。由于容器内物料为液体炸药,具有强烈腐蚀性,所以凡与容器内物料接触的部分如容器筒体与封头材料均选用不锈钢0Cr18Ni9,夹套内物料为煤油,微弱腐蚀,选用Q235-A做材料。以下对两种材料做简单介绍。

0Cr18Ni9:0Cr18Ni9属于奥氏体不锈钢,由于含碳量较低,因而有良好的加工成型

性能和抗氧化性能,有良好的冷变形性能,可以进行弯曲,卷边等工序,作为不锈耐热钢广泛用于食品用设备,一般化工设备等,适于制造深冲成型的零件如垫片及容器等。在焊接上,可采用各种方法进行焊接,一般尽量不用气焊,焊前需进行预热,焊后应迅速冷却。

Q235-A:韧性和塑性良好,有良好的热加工性和焊接性能,一般在热轧状态使用,用途较广泛。

1.1 初步计算筒体直径Di

容器内物料为液体炸药,黏度1.4—4.0 PaS,密度0.8 g/cm3。

容器有效容积2立方米,操作压力0.6兆帕。

VgH0.8,1.3。因为物料黏度较大,取装料系数取长径比先忽略封头容积,VDi得全容积计算公式为:

VVg4DiH 式(1.1)

2其中:V—全容积m3 ;η—装料系数0.8;Vg—容器有效容积2m3Di—容器公称直径,即内径m; H—容器圆筒高m

计算得Di=1.347m=1347mm,圆整到1300mm。

1.2 确定筒体高度H

筒体高度=(全容积-封头容积)/圆筒截面积即:

VVdH= 式(1.2)

2Di4其中:Vd—封头容积m3选标准椭圆形封头,当Di=1300时,查得Vd=0.321m3。 计算得H=1.4m=1400mm。

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2天津机电职业技术学院毕业设计

1.3 计算液面高度Hl

液面高度=(有效容积-下封头体积)/圆筒截面积+封头直边高度h0+封头曲面深度h1即:

HlVgVd4Di2h0h1 式(1.3)

其中:Hl—液面高度mm

h0—封头直边高度mm,查得当公称直径为1300时h0=25mm h1—封头曲面深度mm,查得h1=325mm 计算得Hl=1615mm。

由以上计算,得:釜体总高度H0=H+ 2(h0 +h1)=2100mm,夹套高度捎高于液面,取夹套总高H0j=10mm,夹套圆筒高Hj=H0j- h0j -h1j=10-25-375=1240mm。其中h0j 和h1j分别为夹套封头直边高和曲面深度,分别查得为25mm和375mm。搅拌釜总体尺寸见图(1.1)。

图1.1 搅拌釜总体尺寸

1.4 封头计算

封头所选用材料0Cr18Ni9相关物理性能如下: 许用应力[ζ]90°C=[ζ]95°C=137MPa 弹性摸量E=1.88×105 Mpa

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3天津机电职业技术学院毕业设计

1.4.1 封头厚度计算(内压工况)

内压P=0.6 Mpa,温度90°C。厚度计算公式:

KPcDi 式(1.4)

2[]t0.5Pc其中:K—压力增强系数,对标准椭圆形封头K=1; Pc—操作压力0.6Mpa; [ζ]t—t0C下材

[ζ]90°C=137Mpa;

θ—封头焊封系数,θ=1.0; 计算得:δ=3mm 。

封头名义厚度δn=δ+C1+C2+Δ=6mm。 其中 C1—钢板负偏差,取C1=0.6mm;

C2—钢板腐蚀裕量,取C2=1mm。 封头有效厚度δ

e

=δn -C1-C2=6-0.6-1.0=4.4mm。

1.4.2 封头厚度(外压工况)

椭圆封头当量球壳内半径Ri=K1Di,其中K1由椭圆长短轴比值确定,对标准椭圆形封头,可查得K1=0.9,所以Ri=0.9×1300=1170mm。假设其名义厚度为δ厚度δe=δn -C1-C2=6-0.6-1.0=4.4mm。

计算许用外压:

[p]=

B 式(1.5) Ri/en

=6mm,有效

Ri/e1170/4.4266; 0.1250.125/2660.00047 A=

Ri/e由此查得B=55Mpa。

B许用外压[p]==55/266=0.21 Mpa>0.1Mpa,合格。

Ri/e取名义厚度为δ

n

=6mm。

1.5 圆筒计算

圆筒材料与封头相同,为0Cr18Ni9,圆筒焊缝系数取0.85。

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4天津机电职业技术学院毕业设计

1.5.1 内压圆筒计算厚度

计算得:δ=3.4mm

钢板名义厚度δn=δ+C1+C2+Δ=3.4+0.6+1.0+Δ=6mm; 有效厚度δ

e

2tPcDi 式(1.6)

=δn -C1-C2=6-0.6-1.0=4.4mm。

其中C1、C2意义取值同封头。

校核:实际采用温度下应力:

CPc(Die)0.6(13004.4)90c90MPa[]116.5MPa, 合格。所以

2e24.4内压工况时,取δ

n

=6mm。

=6mm,δe=4.4mm。圆筒外径:

1.5.2 外压圆筒计算厚度

假设外压工况时,釜体圆筒厚度为δD0=Di2δ

n

n

=1300+2×6=1312mm,圆筒计算长度应计入直边高度和曲面深度的1/3,

1所以圆筒计算长度 LHjh0h1=1256+25+325/3=1400mm。

3故有L/D0=1400/1312=1.07

D0/δe=1312/4.4=298.2

查得A=0.00024,B=31Mpa,釜体许用外压 [p]=

B=31/298.2=0.104MPa>0.1Mpa,满足稳定设计要求。 Ri/e综合内外压工况,将圆筒厚度定为6mm。

1.6 夹套计算

Q235-A,许用应力[ζ]95

t°C

=137Mpa。夹套圆筒及封头厚度计算公式相同,如下:

式(1.7)

PDj2P 计算得δ=0.1×1500/(2×153×0.85-0.1)=1mm

名义厚度δn=δ+C1+C2+Δ=1+0+2+Δ=6mm 有效厚度δ

e

=δn -C1-C2=6-0-2=4.0mm

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5天津机电职业技术学院毕业设计

1.7 液压试验状态稳定校核

夹套按内压容器确定水压试验压力,计算式如下:

PT1.25P 式(1.8) t1,计算得夹套水压试验压力为: tPT1.25P1.250.10.125MPa

容器为内压容器,因此水压试验压力计算式同夹套,计算得容器水压试验压力为:

PT1.25P1.250.60..75MPa

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6天津机电职业技术学院毕业设计

第2章 搅拌功率计算

2.1 搅拌器选型及尺寸确定

根据不同的搅拌过程,搅拌器的基本形式有下列几种:桨式搅拌器,涡轮式搅拌器(开启涡轮和圆盘涡轮),推进式搅拌器,锚式搅拌器,框式搅拌器,螺带式搅拌器,螺杆式搅拌器,圆盘锯齿式搅拌器。其中桨式搅拌器有平直桨叶和斜桨叶两种,开启涡轮式搅拌器有平直叶涡轮,斜叶涡轮和后弯叶涡轮三种,圆盘涡轮式搅拌器有平直斜桨叶和后弯桨叶三种。在正常运转时,平直桨叶的桨式搅拌器,开启涡轮式搅拌器,圆盘涡轮式搅拌器均属于径向流搅拌器。

由于物料黏度μ=14~40Pa·S,轴转速n=100r/min,选择直叶圆盘式涡轮搅拌器,其常用运转条件n=10—300转/分钟,常用介质黏度范围〈5×104mPaS,最高转速600转/分钟。液体流动状态为径向流,一般对流动状态为径向流的应设档板挡板为搅拌器的附件,其作用是消除搅拌器在搅拌液体时产生的涡流(容器中心的“圆柱状回转区”)使晶向流型搅拌器产生轴向液流和剪切作用,增大搅拌强度。当被搅拌液体的黏度μ〉5Pa·S时,不设挡板,因为在高黏度的液体搅拌时,有挡板反而会干扰液体的搅拌流动,降低搅拌效果。本设计由于液体炸药黏度大于5Pa·S,所以不设挡板。同时由于物料具有强烈腐蚀性,搅拌器材料选用不锈钢。结构如图(2.1)。

搅拌器的主要尺寸与搅拌容器的内径有关,它们之间存在一定的比例关系,只有按这种比例关系确定的搅拌器尺寸才能获得较好的搅拌效果和搅拌效率。

另外,搅拌器的搅拌效果和搅拌效率还与搅拌器在搅拌容器内的位置和液柱高度有关,其有影响的关系参数如下:

1、 搅拌器至搅拌容器底的距离,C; 2、搅拌器浸入搅拌容器内液面下深度,S; 3、搅拌容器内液体装填高度,Hl; 4、多层搅拌器相邻搅拌器间距,SP;

对于必须进入人孔装拆的搅拌器,应设计成可拆结构,其拆开后最大尺寸的组件应能保证从人孔中顺利通过。以上各参数具体数值确定见后。

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7天津机电职业技术学院毕业设计

图2.1 圆盘涡轮式搅拌器结构图

容器直径Di与夹套直径Dj关系为Dj/Di=0.33(推荐植),由此计算得 Dj=0.33×1300=429mm,圆整到标准值,取Dj=500mm。

Dj:l:h=20:5:4,得:Dj=500mm(搅拌器直径); l=125mm(搅拌器桨叶长) h=100mm(搅拌器桨叶高); Zj取6(叶片数量)

查标准直叶圆盘式涡轮搅拌器尺寸表,得搅拌器相关尺寸为:

Dj=500mm;h=100mm;h1=70mm;h2=14mm;h3=40mm; l=125mm;d=65mm;d1=95mm;d2=100mm;d3=330mm;δ=8mm;d0=M10:δ1=8mm;

键槽:b=18mm;t=19mm;质量:12.83kg;材料:0Cr18Ni9;

2.2 搅拌功率计算

2.2.1 每一个搅拌器的搅拌功率准数P01、P02计算

nDj28001.670.52雷诺数Re=8.5,查圆盘涡轮搅拌器功率准数图,得

40P0=P01=P02=10

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8天津机电职业技术学院毕业设计

2.2.2 双层搅拌器总功率准数P0C的计算

双层搅拌器总功率准数P0C的计算公式为:

P0cP01P01P0n/P0 式(2.1) 其中:P0n/P0—多层搅拌器总功率准数P0c的系数,查多层搅拌器总功率准数P0c的系数图,得P0n/P0=0.75。

计算得P0c=10+10×0.75=17.5。

2.2.3 功率准数校正总系数k的确定

功率准数校正总系数k的计算公式为:

kkTkBkekckskzkbklk kT—搅拌容器直径校正系数,kT=Di0065=13000.065=1.59; kB—挡板校正总系数,1; ke—容器底形状校正系数,1.0; kc—容器与容器底距离校正系数,1.0; ks—搅拌容器潜液深度校正系数,0.99; kz—搅拌器桨叶数量校正系数,1.0; kb—搅拌器桨叶宽度校正系数,1.0; kl—桨叶长度校正系数,1.0;

kδ—桨叶厚度和圆盘厚度校正系数,1.05;

所以k=1.59×1×1×1×0.99×1×1×1×1.05=1.65

2.2.4 多层搅拌器总功率(Pc)

PckPn3D50cj 计算得Pc=1.65×17.5×800×1.6673×0.55

=3.344KW

第3章 搅拌强度计算

3.1 搅拌器设计功率

3.1.1 电动机的计算功率和额定功率

1、电动机的计算功率PM

PPsPmMKW 1其中:Pc—搅拌轴轴功率,3.344KW;

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式(2.2)

式(2.3)

式(3.1)

9天津机电职业技术学院毕业设计

Pm—搅拌轴轴封处摩擦损耗功率,KW; 由于物料为危险介质,选双端面机械密封。

Pm=1.8d0×10KW 式(3.2) 1.2

-3

计算得Pm=1.8×651.2

×10-3KW=0.27KW

η1—搅拌机传动装置各零部件的传动效率,取η1=0.94; 计算得PM=(3.344+0.27)/0.94=3.84KW 2、电动机的额定功率PN

选YB系列隔爆型异步电动机,型号YB112M-4, PN=4KW

3.1.2 每层搅拌器的设计功率Pq(Z=2)

有关搅拌容器与搅拌器之间的尺寸及搅拌器层数确定见后。

P1PnPmqZKW 其中:Z—搅拌器层数

计算得Pq=(0.94×4-0.27)/2=1.745KW

3.1.3 搅拌器每个桨叶强度计算用设计功率

PPqjZ j其中:Zj—每个搅拌器桨叶数 计算得Pj=1.745/6=0.29KW

3.2 搅拌器桨叶材料的许用应力

3.2.1 弯曲许用应力

tbnbMPa 其中:ζbt—桨叶材料在设计温度下的抗拉强度,

ζbt=520MPa nb—安全系数,nb =3.5 计算得 [ζ]=520/3.5=148.6Mpa

扭转许用应力 [η]=0.577 [ζ] Mpa 计算得[η]=0.577×148.6=85.7Mpa

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式(3.3) 式(3.4)

式(3.5)

式(3.6)

10天津机电职业技术学院毕业设计

3.3 圆盘涡轮式搅拌器强度计算

3.3.1 弯矩MI

桨叶危险截面I—I,图3.1

PqxrMI9553Nm 式(3.7)

Zjnx其中:x0.75R1R2R1R23443201

式中R1=Dj/2=250mm;R2= R1-L=250-125=125mm; rd mm321651.7452011655Nm 计算得 MI=955361002013.3.2 抗弯截面模数WI(I—I断面处)

bWIe 式(3.8)

62其中:δe—桨叶有效厚度,δe=δ-C1-C2=8-0.8-1=6.2mm;b—桨叶宽度,100mm 计算得:WI=100×6.2/6=1mm

2

3

3.3.3 弯曲应力σI

MI103IMPa 式(3.9)

W计算得:ζI=5×10/1=7.8MPa<[ζ]=148.6Mpa,符合强度条件。

3

图3.1 搅拌器危险截面

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11天津机电职业技术学院毕业设计

第4章 搅拌轴机械计算

4.1 搅拌容器主要尺寸计算及搅拌器层数确定

搅拌容器直径Di=1300mm;

搅拌器直径Dj=0.385×1300=500mm; 桨叶高度h=b=100mm;

挡板与容器壁间距Sb=Di/60=22mm; 挡板厚度Wb=Di/12=108mm;

搅拌容器离釜底距离C≈Dj=500mm,取C=500mm; 搅拌器潜液深度S=Hl-C=1615-500=1115mm;

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12天津机电职业技术学院毕业设计

液面高度Hl=1615mm; 原盘直径d=d3=330mm; 桨叶厚度δ=8mm; 圆盘厚度δd= Dj/50=10mm;

搅拌器转动时影响的液体范围大约为上下一个搅拌器直径,由于Hl>>2Dj,所以设搅拌器层数为Z=2,两个搅拌器之间间距Sp按标准取Sp=1.4 Dj=700mm。4.2 搅拌轴机械计算

4.2.1 按扭转变形控制的轴径d1的计算

搅拌轴材料选用不锈钢0Cr18Ni9。 按扭转变形控制的轴径d1的计算公式如下:

d1155.44MnmaxG1N4 0mm

图4.1 圆盘涡轮式搅拌器和容器配置图

其中[γ]—轴的许用扭转角,对悬臂轴[γ]=0.350/m;

Mnmax--搅拌轴传递的最大扭矩,计算式如下:

MPNnmax9553n1(Nm) 计算得Mnmax=360 N·m

G—搅拌轴材料的剪切弹性摸量,79.4Gpa=7.94×104

Mpa; N0—空心轴内外径比值,对实心轴N0=0; 计算得:d1155.443600.357.9410452.4mm - 12 -

式(4.1)

式(4.2)

13天津机电职业技术学院毕业设计

按标准圆整到d1=500mm。 搅拌轴实际扭转角:

合格。

5836MnmaxGd4(1N0)45836360 0.150.35 式(4.3)

79400.2.2 搅拌轴及搅拌器(包括附件)有效质量的计算

1、搅拌轴悬臂长计算(图4.2)

图4.2 搅拌轴悬臂长

搅拌轴悬臂长L1=搅拌轴深入釜内长度H0-C+上封头厚度δ+法兰高度h2+底盖高度s+搅拌侧轴承与底盖上表面高度H1

H0-C=2100-500=1600mm;δ=6mm; h2=65mm; s=50mm; H1=279mm;

所以:L1=1600+6+65+50+279=2000mm; L2= L1-Sp=2000-700=1300mm;a560mm; 法兰、底盖、机架选型即相关尺寸确定见后。 2、搅拌轴有效质量mL1e的计算

搅拌轴有效质量=轴自身质量+轴附带的液体质量

对悬臂轴:

mL1e4dL1L1s(1N0)109kg 式(4.4)

22其中:mL1e--搅拌轴有效质量,kg;

dL1—悬臂轴L1段实心轴轴径,65mm; L1--搅拌轴悬臂长,2000mm;

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14天津机电职业技术学院毕业设计

ρs—搅拌轴材料密度,ρs=7930kg/m3;

ρ—物料密度,ρ=800 kg/m3;

计算得:mL1e6522000793080010958kg

43、搅拌轴(包括附件)的有效质量mie计算

搅拌轴(包括附件)的有效质量mie=搅拌器自身质量+附带液体质量 对一个搅拌器:

miemiki4Djibicosi109kg 式(4.5)

2其中:mi—搅拌器质量,m1=m2=12.83kg; ηki—搅拌器附加质量系数,η

k1=ηk2=0.53;

Dji—搅拌器直径,Dj1=Dj2=500mm; bi—桨叶宽度,b1 =b2=100mm; ρ—物料密度,ρ=800 kg/m3; θi—桨叶斜角,θ计算得:

m1e=m2e=12.83+0.53×

1=θ2=0;

2-9

×500×100×800×cos0×10=21.2kg 44.2.3 搅拌轴临界转速计算

悬臂及跨间二轴段直径相等,作用着集中质量的悬臂轴一阶临界转速的计算。 1、轴的有效质量mL1e在搅拌轴末段S点处的当量质量W

140a2231L1a99L1 WmL1e 式(4.6) 2420(L1a)计算得:W=14.7kg

2、第I层搅拌器有效质量mie在搅拌轴末端S点处的相当质量Wi

2WiLiLia22L1L1amie 式(4.7)

其中:Li—D第I层搅拌器悬臂长,L1=2000mm,L2=1300mm; 计算得:W1=m1e=21.2kg;W2=6.5kg 3、在S点处所有相当质量的总和Ws

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15天津机电职业技术学院毕业设计

WsWWi 式(4.8)

i1z计算得:Ws=14.7+21.2+6.5=42.4kg

4、具有两个搅拌器的等直径悬臂轴的一阶临界转速nk

nK114.7dL12E(1N0)L1(L1a)Ws24 式(4.9)

计算得nK114.7652188000319r/min 22000(2000560)42.4刚性轴叶片式搅拌轴的允许转速比n/nk0.7,实际n/nk=0.31<0.7,合格。

4.2.4 按强度计算搅拌轴的轴径d2

1、搅拌轴轴径d2的强度计算

公式:d217.23Mte1N024mm 式(4.10)

其中:Mte--搅拌轴扭矩和弯矩同时作用下的当量转矩,N·m;

MteMnM2Nm 式(4.11) 式中:Mn—按传动装置效率η1计算的搅拌轴传递扭矩

95539553Pn140.94360Nm 式(4.12) Mnn100 [η]—轴材料的许用剪应力,Mpa; 52032.5MPa 式(4.13) []b1616ζb—轴材料的抗拉强度,520Mpa

M—搅拌轴弯矩总和

M=MR+MA 式(4.14) 2、由径向力引起的轴的弯矩MR计算

MRFhiLi9.81mw1LesinFeLe103 N·m 式(4.15)(1) Fhi—第i个搅拌器上流体径向力

Mnqi103 Fhi=K1 式(4.16)其

3Dj8中:K1—流体径向力系数

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16天津机电职业技术学院毕业设计

K1=K1′K1uK1bK1eK1i 式(4.17)

图4.3 等直径悬臂轴受力图

图4.4 悬臂段计算长度

K1′--基本流体径向力系数,K1′=0.09; K1u—物料黏度修正系数,K1u =0.8; K1b—容器内平直挡板修正系数,K1b =1;

K1e—搅拌器偏心安装修正系数,K1e =1(偏心距=0);K1i—容器内件修正系数,K1i=1;

K1=0.09×0.8×1×1×1=0.072

Mnqi--第i个搅拌器功率产生的扭矩

MPqinqi9553n(Nm) 计算得Pq1= Pq2=1.745KW,所以

Mnq1Mnq295531.745100166.7Nn - 16 -

式(4.18)已

17天津机电职业技术学院毕业设计

166.7103N 所以:Fh1 =Fh2=0.07235008(2) Li—第I层搅拌器悬臂长,L1 =2000mm,L2=1300mm; (3) mw1—搅拌轴与各层搅拌器的组合质量

mw1mL1mikg 式(4.19)

i1Z其中:mL1—悬臂段L1质量,按下式计算:

22mL1dL1(1N0)L1s109kg 式(4.20)

4计算得mL1465220007930109kg52.6kg

mi—搅拌器i的质量,m1 =m2=12.83kg

所以mw1=52.6+12.83×2=78.26kg

(4) Le—搅拌轴各层搅拌器(包括附件)组合重心离搅拌侧轴承的距离

LzLe=miLimL11/mw1 mm 式(4.21)

2i1式中各参数值均已知,代入计算得Le=705mm

(5) α—搅拌轴轴线与安装垂直线(容器中心线)的夹角,由于是垂直安装,α=0。 (6) Fe—搅拌轴及搅拌器(包括附件)在组合重心处由质量偏心引起的离心力。 2125Femw1ne10N 式(4.22) 291(n/nk)其中:[e]—搅拌轴及各层搅拌器(包括附件)在组合重心处的许用偏心距

G e9.55

nG—平衡精度等级,对操作压力高,转速高,介质为危险物料的情况,G=2.5mm/s。 计算得:[e]=9.55×2.5/100=0.24mm 所以,Fe2178.2610020.24105N2.28N 291(0.31)-3

代入式(4.14)得:MR=[(2000+1300)+9.81×78.26×705×sin0+2.28×705]×

10=213N·m

3、由轴向力引起的搅拌轴弯距MA

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18天津机电职业技术学院毕业设计

(1)MA的粗略估算:当P<2MPa或轴上任一搅拌器θi=0时,取MA=0。 (2)代MA=0入式(4.14)中求得M=MR+MA=213 N·m

(3)将M代入式(4.12)中求得Mte36022132Nm418.3Nm (4)代Mte入式(4.11)中求得d217.23(5)求MA的精确值,公式如下:

d(1N0)MAkBFAL1103Nm 式(4.23)

82418.3mm40.3mm 32.5 其中:kB—压缩系数 kB=

sLB2EI0S0 式(4.24) dL140.321N010.1mm; 442 ζs—轴屈服极限,205MPa; I0—搅拌轴回转半径,I0 LB—搅拌轴计算段长mm,图(6)。LB=L1+a/2=2000+560/2=2280mm S0—轴承形式系数,S0=0.25

LB2280 45.15﹥110,代入公式(4.22)计算得:

I0S010.10.25205451.5 kB=22.5 21880002 FA—作用在搅拌轴上的轴向合力 FAd02p4FWcosFVi 式(4.25)

Fvi—流体作用在第I层搅拌器上的轴向推力,由于θi=0

所以Fv1=Fv2=0

Fw—当量长度为LT的轴与搅拌器重力和

FW2.452dL11N0LTs109.81mi 式(4.26)

229i1ZLT—当量长度,LT= L1=2000mm,见图6

计算得:FW=450N,重力方向向下,取正值。

40.320.6450cos0315Nm﹤0,轴受压。 所以得:FA4- 18 -

19天津机电职业技术学院毕业设计

计算得MA的精确值为MA=35.7 N·m﹥0,应返回式(4.10)(4.11)(4.13) 重新计算d2。

M=MR+MA=213+35.7=248.7 N·m Mte3602248.72Nm437.6Nm d217.23437.6mm41mm﹤d1=65mm,实际选用轴径65mm,安全。 32..2.5 搅拌轴径向位移计算及按其在轴封处的允许径向位移验算轴径

1、由轴承径向游隙S′、S″引起轴上任一点离图7中轴承距离y处径向位移δ1y

SySS1ymm 式(4.27)

2a2其中:S′、S″--轴承径向游隙,S′=S″=0.03mm

1y0.03y0.030.03mm 256022y

2、受流体径向力Fhi作用引起的径向位移δ 2yZ2FhiLiya2Amm 式(4.28) i16EIL1Li 其中:IL1—悬臂段惯性矩,IL1dL46876240mm4

λ—悬臂段惯性矩与跨间轴段惯性矩之比,两段直径相等,所以λ=1。

13yA—当yLi时,ALLii2Liy; 当y﹥L时, A3iy23、由搅拌轴与各层搅拌器(包括附件)的组合质量偏心引起的离心力在轴上任一点的径向位移δ

3y

3yekyn(k)21nmm 式(4.29)

3y2ay22Leyky—位置系数,当yLe=705mm时,kyLeaLe - 19 -

20天津机电职业技术学院毕业设计

2Le3ayL22y 当y﹥Le时,kyeyaLe 

nn--临界转速与实际转速之比,=3.19 nknk4、总的径向位移δy

轴封处:y=l0=279mmLe=705mm,l0=279mmL2=1300mm, 将各参数值代入式(4.27)(4.28)(4.29)得: (yl0)1y2y3y0.15mm;

图4.5 轴径向位移受力模型图

轴封处搅拌轴允许径向位移:

yl0.1K30d 式(4.30)

K3—搅拌轴径向位移系数,K3=0.3

计算得yl00.10.365=0.242mm﹥(yl0)0.15mm,合格。 轴端处:y=L1=2000mm﹥Le,且﹥L2,代入式(4.25)(4.26)(4.27)得:

(yL)1y2y3y0.7mm

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21天津机电职业技术学院毕业设计

4.2.6 搅拌轴轴径的最后确定

通过上述计算,可见当d=65mm时,满足各项强度要求,同时也满足扭转变形、径向总位移、临界转速比0.7的要求,所以最后将轴径定为65mm。

4.3 搅拌器与搅拌轴的连接

搅拌器上轴套与搅拌轴之间采用键连接,并用止动螺栓将其固定。选用A型平键,标记:键A18×63。

4.3.1 连接强度计算

1、挤压强度条件

K4103MnqdhKL 式(4.31)

其中:hK—键高,11mm; L—键工作长度,63mm;

4103166.714.8MPa 计算得K651163许用挤压应力[]K69MPa﹥K14.8MPa,满足挤压强度条件。 2、切强度条件

K2103MnqdBL 式(4.32)

其中:B—键宽,18mm 计算得:K2103166.74.5MPa 651863许用剪切应力[]K85MPa﹥K4.5MPa,满足剪切强度条件。

第5章 搅拌釜传动装置

5.1 传动装置的组成

组成传动装置的各零部件:包括电动机、减速机、机架、传动轴、搅拌轴、传动轴联轴器、搅拌轴釜内联轴器、机械密封、安装底盖、凸缘法兰等。

机架采用单支点机架,机架轴承与减速机输出轴轴承作为悬臂轴的两个支点。

5.2 传动装置的标准零部件

5.2.1 凸缘法兰

1、用途:连接搅拌机传动装置与安装底盖。 2、适用范围:设计压力0.1—1.6Mpa;

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22天津机电职业技术学院毕业设计

设计温度-20--300℃。

3、法兰选型:因为物料具有强烈腐蚀性,所以选择不锈钢0Cr18Ni9作为法兰材料,

选用M型凸缘法兰。公称直径:300mm。

5.2.2 安装底盖

1、用途:支承机架、轴封。

2、适用范围:设计压力0.1—1.6Mpa; 设计温度-20--300℃。

3、底盖选型:选RS型安装底盖,R(凸面),S(上装式传动轴)。材料选用不锈钢

0Cr18Ni9。公称直径:300mm。

5.2.3 机架

1、用途:标准单支点机架用以支承减速机和搅拌釜的传动轴。 2、适用范围:适用于搅拌轴轴径30—160mm。

3、机架选型:选用A型单支点机架,主要材料为碳素钢Q235-A。 公称直径:300mm。 机架内传动轴与减速机输出轴连接采用带短节联轴器,能在拆卸联轴器的短节后,在不拆除减速机和机架的条件下装拆机架的中间支点轴承箱和轴封。

5.2.4 机械密封

选型:由于物料属于易燃易爆有毒介质,所以选用轴向双端面非平衡型机械密(2004)型,压力等级1.6Mpa,使用温度-20--150℃。介质端材料用不锈钢0Cr18Ni9。

5.2.5 减速机选型及说明

选择摆线针轮行星减速机,减速比范围:87-9,输出轴转速范围:16-160转每分钟,功率范围:0.6-30KW,效率≥0.9;

主要特点:本机利用少齿差内啮合行星传动的减速装置,故减速比大,传动效率高,

结构紧凑,装拆方便,寿命长,承载能力高,工作平稳,重量轻,体积小,故障少,有取代涡轮减速机的趋向。

应用条件:对过载和冲击载荷有较强的承受能力,可短期过载75%,起动转矩为额定

转矩的2倍,允许反正旋转,可用于有防爆要求的场合,与电动机直联供应。

5.2.6 电动机选型及说明

选用YB系列隔爆型异步电动机,型号YB112-M4,额定功率4KW,额定电流15.4A,额定转速1440转每分钟,效率87%。

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23天津机电职业技术学院毕业设计

说明:YB系列隔爆型异步电动机广泛用于有爆炸气体混合物存在的场所,工作环境

温度不超过40摄氏度,海拔不超过1000m。

第6章 搅拌釜传热结构及强度计算

6.1 夹套尺寸

选择整体U形夹套,适用最高温度300摄氏度,适用最高压力1.6兆帕。材料用Q235-A。

D1—夹套内径; D2—容器内径; S1—容器壁厚; S2—夹套壁厚;

D2/D11.2,所以D21.2 D1=1.2×1300=1560mm,取D2=1500mm; S2/S11.2,所以S21.2 S1=1.2×6=7.2mm,实际计算结果S2=6mm;

6.2 夹套与容器筒体连接处结构(图6.1)

夹套与容器筒体连接处采用封口锥结构。 相关尺寸计算:α—封口锥半顶角,取450。 r0—封口锥过渡区转角半径;

lR—与夹套封口锥相接的夹套加强区实际长度;

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24天津机电职业技术学院毕业设计

e0—容器外壁至夹套壁中面距离,

e00.5D2S2D12S197mm

e0.5S2970.56320mm,取r0=300mm; r001cos1cos450 lR0.5D2(S2C)0.51500(62)38.7mm,取lR=40mm

图6.1 夹套与容器 图6.2 夹套封头 筒体连接处结构 与容器封头的连接结构

6.3 夹套封头与容器封头的连接结构(图6.2)

夹套封头必须焊接在容器封头上,焊接处的连接圆半径直径满足d10.4D2。 相关尺寸:S3—容器封头厚度,已知为6mm

S4—夹套封头厚度,已知为6mm

d1—夹套封头与容器封头的连接圆直径,d10.4D2=600mm,取200mm

6.4 夹套容器的附件结构

夹套容器的附件结构包括进出料管口,排气口等,具体尺寸见“搅拌釜管口计算”。

6.5 U形夹套容器的强度计算

6.5.1 U形夹套容器的强度计算公式适用条件

1、直径比D2/D11.2; 2、壁厚与直径比:0.0010.0013、壁厚比:S2S11.2

D2S1 0.51D1D1- 24 -

25天津机电职业技术学院毕业设计

4、封口锥过渡区转角半径r0e00.5S2

1cos5、夹套封头焊接处连接圆半径d10.4D2 实际尺寸均符合以上条件。

6.5.2 夹套容器强度计算

1、夹套覆盖范围内承受内外压的容器筒体及承受内压的夹套筒体强度计算、稳定计算见P1—3。

2、夹套覆盖范围内承受内外压的容器封头及承受内压的夹套封头强度计算、稳定计算见P1—3。计算夹套封头时,其连接圆半径d1部分不按开孔考虑。 3、夹套封口锥

(1)、轴向力系数A :AD1D2d1D222 式(6.1)

1500130020020.85 计算得A21500(2)辅助系数,,,,,R1,R2, a、容器壳体与夹套壳体的间距系数ε

 计算得e0D2S2C97 式(6.2)

6215001.25

b、夹套封口锥过渡区转角半径系数ρ

r00.5S2 式(6.3)

D2S2C 计算得 3000.560.05

621500 c、夹套封口锥连接长度系数λ

20.45 式(6.4)

计算得 21.250.450.051.8 d、容器壳体与夹套壳体强度比系数χ

1S1C 1.252S2CD1S1CP1D1(P1P2)D11式(6.5) 12SC2SCD2S2C1111- 25 -

26天津机电职业技术学院毕业设计

其中 P1—工作或试验条件下容器内设计压力,1.0Mpa。 P2—工作或试验条件下夹套内压力,0.13Mpa。 [ζ]1—设计温度下容器壳体材料许用应力,137 Mpa。 [ζ]2—设计温度下夹套壳体许用应力,113 Mpa。 C—壁厚附加量,对容器取1.6mm,夹套取2mm。 S1、S2—容器、夹套壁厚,分别为6mm,6mm。 计算得χ=1.53 e、计算焊封系数R1,R2

R1r1 式(6.6) R2r2 式(6.7) r2,r1--夹套筒体与容器筒体的环焊封系数,取1。

f—夹套封口锥相对有效承载长度系数μ

R1R2min,4cossin 式(6.8)  计算得:μ=0.71

(3) 夹套封口锥的连接系数B

B2S2CminX1,X2,X3 式(6.9) D2式中X1--X3—辅助系数

cosR1R2cos450 X1f14cos1.25111.82.63.0 04cos45 X2f21R22112.83

R1R22 X3f3f1.5310.713.24 44cos40.710.707 其中,f1--f4为夹套封口锥的强度系数,查得f1=2.6,f2=2,f3=1,f4=1 计算得B=242.830.29 15004、 夹套封口锥许用内压力

22S2CR2B P2 式(6.10)

D2S2CA- 26 -

27天津机电职业技术学院毕业设计

计算得:P2215340.290.28MPaP20.1MPa 合格。

150040.855、夹套封口锥壁厚

夹套封口锥壁厚应等于或大于与其相接的夹套筒体壁厚,取S2R=S2=6mm。 6、夹套封口锥的重力作用载荷强度校核

重力G1和G2在封口锥中引起的轴向力F为F=G1(支座设置在夹套上)。 G1—搅拌容器自重及内部物料重力。

G1=容器筒体重力+封头重力+物料重力=20000N ,所以 F=20000N 封口锥的承载能力(在轴向载荷和夹套内压作用下)

P24F0.14(20000)0.51 合格。 22P2P2D2A0.280.2815000.856.6 支座选型及计算

6.6.1 支座选型

1、支座可装设在整体夹套壳体上或无夹套覆盖的容器壳体上,本设计支座设在夹套上;

2、夹套与支座在容器壳体上的焊接:夹套与支座在容器壳体上的焊封边缘间距

图6.3 B型支座结构

应大于三倍容器壁厚(18mm),且不小于100mm,取110mm。

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28天津机电职业技术学院毕业设计

3、支座选型:选耳式支座,B型,结构如图(6.3)。

6.6.2 支座实际承受载荷的计算

采用4个支座,每个支座实际承受的载荷按下式计算。图6.4。

m0gGe4PhGeSe3Q10KN 式(6.11) nkn 其中,m0—设备总质量(包括壳体及其附件,内部介质及保温层质量),夹套内煤油质量大约为590kg,夹套质量400kg,釜体圆筒包括内部液体质量为2000kg,所以m0为三者之和,3000kg。

Ge—偏心载荷,可近似认为为零。

k—不均匀系数,三个以上支座,k=0.83。

h—水平力作用点至支座底板之间距离,取500mm。 Se—偏心距,取0。 θ—螺栓分布圆直径,D22232b22222l2S1

上式中各参数值已知,求得θ=1584mm。

P—水平力,取水平地震力Pe和水平风载荷Pw中的大值。

Pe0.50m0g 式(6.12)

Pw0.95fiq0D0H0106N 式(6.13)

式中,α0—地震系数,地震设防烈度为8级,α0=0.45。 fi—风压高度变化系数,取0.。

q0—10m高处的基本风压值,取550N/m2

D0—容器外径,1500mm。 H0—容器总高,2100mm。

计算得:Pe0.50.4530009.816700N

Pw0.950.55015002100106N900N 取大值,所以P=6700N。

代入式(63)得Q=11KN<[Q]=60KN 合格。

6.6.3 校核支座反力对容器壁作用的外力矩M0

由于支座反力Q不通过容器中面,所以Q在支撑筒体的同时,还对筒壁作用有外力矩,其值按下式计算:MQl2S111205501.65Nm 103103- 28 -

29天津机电职业技术学院毕业设计

查得许用外力矩[M]=5.68Nm>M 所选用的支座可用。

图6.4 计算Q的参数

图6.5 螺栓分布圆直径ø

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30天津机电职业技术学院毕业设计

第7章 设备管口

7.1 设备所有管口名称

设备上所有管口包括:人孔(1个)、视镜(2)、温度计接口(1)、压力表接口(1)、容器进料口(2)、容器出料口(1)、夹套进料口(2)、夹套出料口(2)。

7.2 各管口选型

7.2.1 人孔选型

选用回转盖不锈钢人孔,公称直径450mm,密封面形式A。

7.2.2 补强计算

圆筒内部所受的工作压力为0.6MPa,所以封头为内压容器

1、补强判别:允许不另行补强的最大接管外径为mm,人孔外径为450mm故需计算是否需要另行补强。

封头所需补强面积按下式计算:

Ad2(1f) 式

etr(7.1)

其中:d—开孔直径,圆形孔接管内径加两倍的厚度附加量,椭圆形和长圆形孔,取所考虑平面上的尺寸(旋长,包括厚度附加量),mm 容器上椭圆形封头人孔开孔直径:

d43821.6441.2mm,d441.2mmD/2650mm,满足等面积开孔补强计

i算的适用条件,故可用等面积法进行开孔补强计算。

—圆筒或球壳开孔处的计算厚度,mm

K1PcDi 式(7.2)

t2[]0.5Pc10.61300 计算得:3mm

213710.50.6  et —接管有效厚度,etntc 6mm

nt —接管名义厚度,nt- 30 -

31天津机电职业技术学院毕业设计

et61.64.4mm

f —强度削弱系数,等于设计温度下接管材料与封头材料许用应力之比值,

r由于两材料相同,所以削弱系数f1,

r计算得:

Ad2(1f)441.2etr2、有效补强范围 (1)、有效宽度B的计算

按下式计算,取二者中较大值

3234.4(11)m13m 23.62Bd22 式(7.3)

nntB2d 式(7.4)

2441.22626465.2mm nnt4m B2d882.m

计算得:Bd2n—壳体开孔处的名义厚度

故B=882.4mm (2)、有效高度计算

①、外侧有效高度按下式计算:

hd441.2651.5mm 式(7.5)

1nth)1150mm(实际外伸高度)计算得:hd446451.5mm 1nt取二者中较小的值,故h51.5mm.

1②、内侧高度

hdnt2h250mm 式(7.6)

计算得:hdnt51.5mm,取二者中较小值,故h50mm

223、等效补强面积

(1)、封头多余金属面积

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32天津机电职业技术学院毕业设计

封头有效厚度en-C=6-1.6=4.4mm 1封头多余金属面积A

A(Bd)()2()(1f) 式1eeter(7.7)

计算得:A(882.4441.2)(4.43)24.4(4.43)(11)617.71(2)、接管多余金属面积 接管计算厚度:

mm2

t(7.8)

pcDi 式

t2[]pc计算得:t0.6441.20.97mm

21370.6接管多余金属面积:

A22h1(ett)fr2h2(etc2)fr 式

(7.9)

计算得:

A2251.5(4.40.97)1250(4.41.0)1693.3mm2 (3)、接管焊缝区面积: A3266=36.0mm2

(4)、有效补强面积: AeA1A2A3617.7693.3361347mm2 4、所需另行补强面积: A4A-(A1+A2+A3)=1323.6-1347=-23.40<0

所以人孔不需另行补强。

127.2.3 试镜

因为物料具有强烈腐蚀性,所以选用不锈钢视镜,公称直径80mm。

7.2.4 其它管口

容器进料口:管外径ø108×6,公称直径100mm;容器出料口:管外径ø76×4,公称直径65mm;夹套进料口:管外径ø57×3.5,公称直径50mm。夹套出料口:管外径ø57×3.5,公称直径50mm;温度计接口:管外径ø38×3.5,公称直径32mm;压力表接口:管外径ø32×3.5,公称直径25mm;冲视镜管接口:管外径ø18×3.5,公称直径15mm。

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33天津机电职业技术学院毕业设计

与各管口焊接的管法兰根据HG20594,20595,20598选取,法兰类型均为板式平焊法兰,材料为Q235-A。

以上各管口补强计算方法同人孔。经过计算,以上各开孔均无须另行补强。

第8 温度控制系统设计

采用电加热器加热。

8.1 电加热器功率计算

1、将介质加热至工作温度所需热量:

Qm(T2T1)c KJ

式中: Q—被加热介质所吸收的热量,kj; m—被加热介质的质量,kg;

T2—被加热介质的工作温度,℃;T2=95℃; T1—被加热介质的初温,℃;T1=20℃;

c—被加热介质的比热容,kj/(kg•℃);对煤油,c=2.1×103J/Kg℃; m的计算: m=ρ

煤油V

其中:V=封口锥体积VZ+圆筒体积VY+封头体积VF

222115001500131213121312m3 VZ=940.0288322222150013123 VY=124012400.515m

22 VF=0.48633212942212223230.3210.158m 2 计算得V= VZ+ VY+ VF=0.0288+0.515+0.158=0.7018m3 煤油密度为840Kg/m3,所以计算得m=840×0.7018=590m3 所以Q590(9520)2.19.3104KJ 2、根据所需热量求电功率:

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34天津机电职业技术学院毕业设计

PQ 3.6t式中: Q—热能,kj; P—电功率,W;

t—电流通过导体时间,h。

9.310410333W10.3KW 计算得:P3.62.5选择JGY2-220/2管状电加热器元件,电压220V,功率2KW,所需电加热器个数为10.3/2=6个。单个质量1.9千克。

8.2 温度控制系统组成

8.2.1 控制系统的简单介绍

控制系统中最简单的一类,单回路控制系统,只有一个闭环,即一个回路。在大多情况下,这种简单控制系统已能够满足工艺生产得要求。但在大型化、连续化和强化,对制造条件要求严格,参数间相互关系更加复杂时,单回路的控制系统不能满足生产要求。

因为反应釜的物料的容量滞后大、干扰强,采用串级温度控制可以获得明显得效果。串级控制系统是相对单回路控制系统较复杂的一种控制系统,是改善调节质量极为有效的方法,在过程控制中得到广泛应用。串级控制系统与单回路控制系统相比,不单纯是再结构上多了一台变松器和一台调节器,而且在功能上具有如下一些特点,其应用场合也与这些特点有关。

1、能够迅速克服浸入副回路的干扰,是串级控制系统的最主要的特点。因此,在设计串

级控制系统时,将主要扰动的进入点位于副回路内。

2、 改善被控对象的特性,提高系统克服干扰的能力。由于副回路等效被控对象的 时间

常数比副对象的时间常数小得多,所以由于副回路的引入而使对象的动态特性有了很大的改善,有利于提高系统克服干扰的能力。

3、主回路对副对象具有“鲁棒性”,提高了系统的控制精度。该串级温度控制系统时由

两套检测变送器、两个调节器、两个被控制对象和一个调节阀组成,其中的两个调节器串联起来工作,前一个调节器的输出作为后一个调节器的给定值,后一个调节器的输出才送往调节阀。在一个闭环的里面,称为副环或副回路,在控制过程中起

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35天津机电职业技术学院毕业设计

着“粗调”的作用;一个闭环在外边,成为主环或主回路,用来完成“细调”任务,以保证被控反应釜温度的稳定。

本次设计的搅拌釜串级温度控制系统组成包括电加热器、温度计、温度调节器、温度检测变送器。

8.2.2 控制系统说明

物料自顶部连续进入容器中,经反应后从底部排出。反应容器内温度要求保持在90摄氏度,为了严格控制反应温度,保证产品质量,对反应容器内温度采取串级控制。方框图及控制系统示意图如图。

在控制系统图中,容器为被控对象,容器内温度为被控变量,温度计为检测元件,电加热器为加热装置。TT1为温度检测变送器1,TT2为温度检测变送器2,TC1、TC2分别为温度调节器。整个控制过程通过调节电压来控制,具体过程为:给温度调节器TC1一个给定值,95ºC。电加热器对夹套内的煤油进行加热,热量通过煤油--容器壁传给物料液体炸药。温度计1测量出容器内液体炸药的温度并通过温度变送器TT1将测量值送给温度调节器TC1,TC1根据给定值95ºC与实际测量的温度值进行比较然后输出一个温度值。这个温度值作为副调节器TC2的输入值,此时副变送器TT2将检测到的夹套内的温度T2送给TC2,TC2将T2与TC1的输入值进行比较,然后将输出值送往调压器,调压器根据要求作出相应调节。

在方框图中,f1,f2分别为一次和二次干扰,一次干扰作用于主对象即容器内温度,可以包括液体炸药的流量变化,进入容器时的温度等等。二次干扰作用于副对象, 即夹套内温度。可见方框图包括两个闭环,采用这种串级控制系统的优点是以夹套温度作为中间变量,将扰动因素f2包含在副环之内,大大减小这些扰动对反应温度的影响。

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36天津机电职业技术学院毕业设计

图8.1 温度控制系统示意图

图8.2 温度控制系统方框图

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37天津机电职业技术学院毕业设计

结 论

通过上述计算及相关说明,最终确定了搅拌釜各部分尺寸,同时也对人孔、视镜、凸缘法兰,安装底盖、机架、减速机、电动机、支座进行了选型及计算,通过校核,搅拌釜各部分均满足强度要求。对搅拌釜各部分所使用材料也进行了选择说明,图纸包括两张0号装配图(一张CAD绘图,一张手工绘图),一张1号零件图、三张1号零部件图。

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38天津机电职业技术学院毕业设计

参考文献

[1] GB150-1998 钢制压力容器[S]

[2] 陈乙崇,衣军,王尚武,杨福媛,于广彦,苏敏贤.搅拌设备设计[M].上海:上海科学技术出版社, 1985.11

[3] 曲文海等. 力容器与化工设备实用手册[M]. 京:化学工业出版社,2000.3 [4] HG 20592~20635-97 钢制管法兰、垫片、紧固件[S]

[5] 成大先,王德夫,姜勇,李长顺,韩学铨.机械设计手册 第三版 化学工业出版社. [6] 董大勤,袁凤隐. 力容器与化工设备实用手册(上、下)[M] 北京:化学工业出版社,2000

[7] 潘家祯. 力容器材料实用手册—碳钢及合金钢[M] 北京:化学工业出版社,1999 [8] 邹增大,李亚江,孔俊生,曲仕尧. 接材料、工艺及设备手册[M] 北京:化学工业出版社,2001.3

[9] 任嘉卉. 差与配合手册(第二版)[M] 北京:机械工业出版社,2000.

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39天津机电职业技术学院毕业设计

致 谢

本次毕业设计在王煦伟老师的认真指导完成,在此对导师表示由衷的感谢,同时也特此致谢。

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