标准椭圆形封头的几何形状

标准椭圆形封头的几何形状、尺寸和质量（1）封头的几何形状形成这种封头的母线是由1/4椭圆线和一条平行于回转轴的短直线光滑连接而成，因而这种封头是由半个椭球和一个高度为h0的圆柱形短节（称它为封头的直边部分）构成。标准椭圆形封头的曲面深度h1与封头公称直径之比为1比4。直边高度按封头的公称直径推荐两种尺寸：当封头公称直径DN小于、等于2000mm时，h0=25mm；当封头公称直径DN大于2000mm时，h0=40mm。（2）封头几何量与质量的计算公式椭圆形封头的几何量与质量的计算公式与四个参数有关，即：长轴半径a，短轴半径b，直边高度h0和钢板厚度P，其计算式列于下表1：表1 椭圆形封头的几何量与质量的通用计算公式坯料直径坯料质量内中或外表面积容积质量注：1.式中长度单位一律用m，钢板密度单位为kg/m3。2.根据需要a、b可按封头内径，中径或外径取值。3.对于以内径为公称直径的标准椭圆形封头，其有关计算公式列下表2。根据表1所列公式，对于任何a、b值的椭圆形封头均可算出其有关各几何量及质量的数值。表2 标准椭圆形封头的几何量与质量计算公式项 目计 算 公 式坯料直径 D0坯料质量 G0内表面积 Fi容积 V封头质量 G注：1.以上各式均按a=0.5Di,b=0.25 Di,按表2通用计算公式导出。2.封头质量公式应按封头中面计算，表中G式曲面部分是按封头外表面计算的。对于以内径为公称直径的封头，其中的Fi和V，可用a=0.5Di和b=0.25Di,代入表1中各式，但对D0、G0和G应以中面为基础，为了计算公式简单，表2中的D0、G0，G式均以外表面作为计算基础（直边部分除外），且作了不影响工程上允许精确度的简化。对于以外径为公称直径的封头，表1中的F和V应该用a=0.5DHP和b=0.25DHP代入，对于G应先算出封头中面面积，这时a=0.5DH0.5P，b=0.25DH0.5P。如果将上述值代入表2有关公式后，得到的计算公式较为繁琐，所以不再给出。（3）数据表根据JB/T47462002钢制压力容器用封头的规定，以内径为基准的标准椭圆形封头形式代号为EHA，以外径为基准的椭圆形封头形式代号为EHB，这两种封头的内表面积、容积和质量分别列于表3、表4、表5中。表3 EHA椭圆形封头内表面积、容积（JB/T47462002）序号公称直径DN/mm总深度H/mm内表面积A/m2容积V/m3序号公称直径DN/mm总深度H/mm内表面积A/m2 容积V/m313001000.12110.00533429007659.48073.456723501130.16030.008035300079010.13293.817034001250.20490.011536310081510.80674.201544501380.25480.015937320084011.50214.611055001500.31030.021338330086512.21935.046365501630.37110.027739340089012.95815.508076001750.43470.035340350091513.71865.997286501880.50900.044241360094014.50086.514497002000.58610.054542370096515.30477.0605107502130.66860.066343380099016.13037.6364118002250.75660.0796443900101516.97758.2427128502380.84990.0946454000104017.84648.8802139002500.94870.1113464100106518.73709.5498149502631.05290.1300474200109019.649310.25231510002751.16250.1505484300111520.583210.98831611003001.39800.1980494400114021.538911.75881712003251.65520.2545504500116522.516212.56441813003501.93400.3208514600119023.515213.40601914003752.23460.3977524700121524.535914.28442015004002.55680.4860534800124025.578215.20032116004252.90070.5864544900126526.642216.15452217004503.26620.6999555000129027.728017.14792318004753.65350.8270565100131528.835318.18112419005004.06240.9687575200134029.964419.25502520005254.49301.1257585300136531.115220.37042621005655.04431.3508595400139032.287621.52812722005905.52291.5459605500141533.481722.72882823006156.02331.7588615600144034.697523.97332924006406.54531.9905625700146535.935025.26243025006657.08912.2417635800149037.194126.59693126006907.65452.5131645900151538.475027.97763227007158.24152.8055656000154039.777529.40533328007408.85033.1198表4 EHA椭圆形封头质量（JB/T47462002）/kg序号公称直径DN/mm封头名义壁厚n/mm2345681012141618202224262830321300 1.92.83.84.8 5.87.82350 2.53.75.06.3 7.610.334004.86.48.0 9.713.116.520.023.644505.97.910.012.016.220.424.829.255007.29.612.114.6 19.624.730.035.340.746.251.865508.611.514.417.423.429.535.741.948.354.861.4760010.113.517.020.427.534.641.849.256.764.271.9865011.715.719.723.8 31.940.248.557.065.674.483.2970013.518.122.727.336.646.155.765.475.385.295.31075015.420.625.831.141.752.563.474.485.6 96.8108.3 1180023.329.235.1 47.159.3 71.583.996.5109.2122.0135.0148.2161.4174.91285026.132.839.452.966.580.294.1 108.1122.3136.6 151.1165.8180.6195.51390029.236.544.058.974.189.3104.8 120.4136.1152.0168.1184.4200.8217.31495032.340.548.8 65.382.199.0116.1 133.3150.7168.3186.0203.9 222.0240.315100035.744.753.8 72.190.5109.1 127.9146.9166.0185.3204.8224.5 244.4264.416110053.764.686.5108.6130.9153.3176.0198.9221.9245.2 268.6292.2316.1340.1364.317120063.576.4102.2128.3154.6181.1207.8234.7 261.8289.1 316.6344.4372.3400.5428.918130089.2 119.3149.7180.3211.1 242.2273.4 304.9336.7 368.6400.8 433.2465.9498.7191400102.9137.7172.7208.0243.5279.2315.2 351.4387.9424.6461.5 498.7536.25 573.8201500117.7157.4197.4237.6278.1318.9359.9401.1442.7484.4526.5568.8611.4654.2211600133.4178.4223.7269.2315.0361.1407.5454.1501.1548.3595.7643.5 691.5739.8注：DN1700以上（至DN6000）的数据没有摘引。表5 EHB椭圆形封头内表面积、容积、质量序号公称直径DN/mm总高度H/mm名义厚度n/mm内表面积A/m2容积V/m3质量m/kg11596540.03610.00091.1623250.03510.00081.4342360.03420.00081.6988480.03240.00072.206652198050.06290.00202.5205660.06160.00192.9950780.05920.00183.915282739360.09300.00364.4653980.09000.00345.857710100.08710.00327.203511120.08420.00308.50351232510660.12920.00586.15291380.12560.00558.090814100.12220.00539.973515120.11880.005111.80181637711980.16710.008410.679517100.16310.008113.188118120.15920.007815.633619140.15530.007518.01702042613280.21160.012013.444421100.20710.011616.624022120.20260.011219.732623140.19820.010822.7709（4）封头标记类型代号 封头公称直径封头名义厚度材料 标准号。例如公称直径325mm、名义厚度12mm、材质16MnR的以外径为基准的椭圆形封头标记为：EHB 3251216MnR JB/T4746 碟形封头的几何形状、形式代号尺寸和质量（1）封头的几何形状和尺寸参数碟形封头的母线由三段曲线光滑连接而成：半径为RCi的大圆弧线0A，半径为r的小圆弧线AB和与回转轴线平行的短直线BC。以这条OABC曲线为母线绕回转轴转一圈所形成的曲面就是碟形封头的中面。因此碟形封头中央部分是一个球面；球面的四周是一个半径为r的环状壳体，称为封头的折边；与折边相连的是一个圆柱形短节，称为封头的直边。在GB150有关碟形封头的介绍中（包括厚度计算公式），其核心的几何尺寸是球面半径Rci，而折边半径r则以取不同的比值确定其大小，至于Rci取多大并未做硬性规定，过去通常取两种尺寸：Rci=1.0Di和Rci=0.9Di。 在2002年颁布的钢制压力容器用封头（JB/T47462002）中，则选定了两种尺寸的碟形封头：碟形封头DHA是指Rci=1.0Di、r=0.15 Di、DN=Di，相当于GB150中M=1.359的碟形封头。碟形封头DHB是指Rci=1.0Di、r=0.10 Di、DN=Di，相当于GB150中M=1.54的碟形封头。对于DHB型封头，由于其球面半径取值最大，折边半径取值最小，所以这种碟形封头是GB150中M值最大的碟形封头，其优点是封头的曲面深度小，但承压能力较差，所以过去国内设计部门很少采用，对于过去推荐的Ri=0.9Di，ri=0.173 Di（M=1.34）碟形封头，由于它的曲面深度hi=0.25 Di，与标准椭圆相同，所以在新修订的封头标准中取消了。封头标记方法与椭圆形封头相同。（2）封头的几何量和质量的计算公式碟形封头几何量和质量的计算公式汇总于表6，看此表时请参看图1。这张表中所列的公式适用于具有各种参数的碟形封头。对于常用的DHA型封头，可以将=1.0，=0.15代入便可得到列于表7中的系列公式。表6 碟形封头几何量和质量计算公式汇总（参看图1）球面半径RC（=1.0、0.9）内表面积Fi/m2Fi=F1+F2+F3，其中F1=2RCh式中h=RC (1sin)F2=2(arr2) +2r2 sinF3=Dh0折边半径r（=0.173、0.15、0.10）a容积V/m3V=V1+V2+V3，其中V1=V2=（a2r+2r32ar2）sin+（ar2r3）sin2 r3 sin3+（ar）r3V3= D2h0坯料直径D0坯料质量G0曲面高度hi封头质量GkgG=FP（钢的=7.85103kg/m3）注：1.一般式F与V中的下标1、2、3分别表示碟形封头的球面，折边与直边三个部分。2.特定式中D为内直径（省略了下标），P为钢板厚度，D、h0、P单位均用m。表7 DHA碟形封头(Rci=Di、r=0.15Di、h1=0.2254Di)几何量和质量的理论计算公式=6541=1.146弧度容积m3直边高度h025V=0.121D3+0.02D2aa=2419=0. 425弧度坯料直径D0=1.193（D+P）+2h040V=0.121D3+0.0314D2坯料质量G0=6.1651.194（D+P）+2h02P103内表面积m2直边高度h025F=1.065D2+0.0785D质量kg直边高度h025G=8.4（D+P）2+0.62（D+P） P10340F=1.065D2+0.1257D40G=8.4（D+P）2+（D+P） P103注：1.上述公式中的D均为内直径（省略下标i）。2.长度单位一律用m（直边高度除外）。（3）数据表DHA与DHB碟形封头的有关几何量分别列于表8和表9。碟形封头的质量需要时可按表6所给的公式计算。表8 DHA碟形封头内表面积、容积序号公称直径DN/mm总深度H/mm内表面积A/m2容积V/m3序号公称直径DN/mm总深度H/mm内表面积A/m2 容积V/m31300930.11940.00503429006949.31583.220923501040.15790.00763530007169.95633.556034001150.20170.010936310073910.61823.913544501260.25090.015037320076111.30134.294255001380.30540.020138330078412.00574.698865501490.36520.026139340080612.73145.128076001600.43030.033340350082913.47845.582686501720.50070.041641360085114.24676.063397001830.57650.051242370087415.03626.5708107501940.65760.062243380089715.84717.1058118002050.74400.074644390091916.67927.6691128502170.83580.088645400094217.53268.2614139002280.93280.104346410096418.40738.8834149502391.03520.104347420098719.30339.53591510002501.14290.1409484300100920.220610.21961611002731.37430.1851494400103221.159210. 93511712002951.62690.2378504500105422.119011.68331813003181.90090.2995514600107723.100212.46491914003412.19610.3711524700109924.102613.28052015003632.51260.4533534800112225.126314.13092116003862.85050.5468544900114426.171315.01692217004083.20960.6524555000116727.237615.93922318004313.58990.7706565100119028.325216.89852419004533.99160.9024575200121229.434117.89552520004764.41461.0484585300123530.564218.93092621005134.95781.2613595400125731.715720.00552722005365.42801.4429605500128032.888421.12012823005585.91961.6412615600130234.082422.27522924005816.43241.8568625700132535.297823.47173025006046.96652.0906635800134736.534324.71043126006267.52192.3431645900137037.792225.99183227006498.09862.6152656000139239.071427.31683328006718.69652.9076表9 DHB碟形封头内表面积、容积序号公称直径DN/mm总深度H/mm内表面积A/m2容积V/m3序号公称直径DN/mm总深度H/mm内表面积A/m2 容积V/m31300830.11270.00443429006028.69022.67792350930.14880.00663530006219.28692.954834001030.18980.00953631006419.90333.250244501120.23580.013037320066010.53963.564655001220.28680.017338330067911.19573.898765501320.34270.022439340069911.87154.252976001410.40350.028440350071812.56724.628086501510.46930.035541360073813.28265.024597001610.54010.043642370075714.01795.4430107501700.61580.052843380077614.77295.8841118001800.69640.063244390079615.54786.3484128501900.78200.075045400081516.34246.8365139001990.87260.08814641008341