20春学期《工业通风与除尘》在线平时作业1

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有害蒸汽和气体的浓度有两种表示方法，一种是质量浓度，另一种是数量浓度。
A:错误
B:正确

射流的能量密集程度高，速度衰减快。
A:错误
B:正确

转速系指风机叶轮每分钟的转数。<span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:错误
B:正确

一般的轴流式通风机，结构简单，噪声较小，风压较低。风压一般不小于<span style="mso-bidi-font-size: 10.5pt" lang="EN-US">500Pa</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:错误
B:正确

风机的轴功率指单位时间内通过风机的空气所获得的实际能量<span style="mso-bidi-font-size: 10.5pt" lang="EN-US">, </span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">它是风机的输出功率</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">, </span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">也称为空气功率。</span>
A:错误
B:正确

事故排风必须的排风量应由经常使用的排风系统或事故排风系统保证。<span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:错误
B:正确

粉尘粒径越大，对人体的危害也越大。<span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:错误
B:正确

人体散热主要通过皮肤与外界的对流和皮肤<span class="GramE">表面汗分蒸发</span>两种形式进行，呼吸和排泄只能排出少部分热量。<span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:错误
B:正确

局部阻力系数的取值除考虑管件的形状外，还需考虑相对粗糙度和雷诺数的影响。<span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:错误
B:正确

在正常运行条件下，除尘器的漏风率不应大于<span style="mso-bidi-font-size: 10.5pt" lang="EN-US">10%</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span><span style="mso-bidi-font-size: 10.5pt"> <span lang="EN-US"><o:p></o:p></span></span>
A:错误
B:正确

根据工业与民用建筑的使用要求，通风和空调系统的风管有时需要把<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的空气，沿风管侧壁的成排孔口或短管均匀送出。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等温</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span></span>
B:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等湿</span>
C:&nbsp;<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等速</span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等量</span>

凡属机械破碎筛分的粉尘大多符合<u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp; </span><span style="mso-spacerun: yes">&nbsp;&nbsp;</span><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></span></u>，特别是舍弃两端的粗大和细小尘粒以后。<span lang="EN-US"><o:p></o:p></span>
A:<span style="mso-bookmark: OLE_LINK1"><span style="mso-bookmark: OLE_LINK2"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">正态分布</span></span></span>
B:对数正态分布
C:威布尔分布
D:不确定的分布

除尘风管应尽可能垂直或倾斜敷设，倾斜敷设时与水平面的夹角最好大于<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">度。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:20<span style="mso-spacerun: yes">&nbsp;&nbsp;</span>
B:30<span style="mso-spacerun: yes">&nbsp;&nbsp;</span>
C:45<span style="mso-spacerun: yes">&nbsp;</span>
D:60<span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span>

粉尘的粒径分布也称为粉尘的分散度，若以颗粒的粒数表示所占的比例称为<u> <span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></span></u>。<span lang="EN-US"><o:p></o:p></span>
A:<span style="mso-bookmark: OLE_LINK1"><span style="mso-bookmark: OLE_LINK2"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">频率分布</span></span></span>
B:质量分布
C:粒数分布
D:颗粒分布

局部排风系统主要由<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、风管、净化设备和风机构成。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">密闭罩</span>
B:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">局部排风罩</span>
C:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">接受罩</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">槽边排风罩</span>

<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">排风口的位置应根据生产设备的工作特点及含尘气流的运动规律确定，排风口应设在罩内压力<u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u>的部位。<span lang="EN-US"><o:p></o:p></span></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">最高<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span></span>
B:最低
C:适中
D:较小

为防止电晕闭塞现象的发生，处理含尘浓度较高的气体时，必须采取措施。气体的含尘浓度超过<u> <span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;</span></span></u>时，必须设置预净化设备。<span lang="EN-US"><o:p></o:p></span>
A:20g/m³<span style="mso-spacerun: yes">&nbsp;</span>
B:30g/m³
C:50g/m³<span style="mso-spacerun: yes">&nbsp;</span>
D:80g/m<u>³</u>

对于<span class="GramE">冷过程</span>的通风柜，应将吸风口布设在通风柜的<u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u>，才能有效地控制有害物。<span lang="EN-US"><o:p></o:p></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">上部<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span></span>
B:下部<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></span>
C:中间
D:上下均可

粉尘在空气中的含量即含尘浓度有两种表示方法，一种是<strong style="mso-bidi-font-weight: normal"><u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u></strong><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，另一种是颗粒浓度。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:<span class="SpellE">ppm</span>
B:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">质量浓度</span>
C:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">体积浓度</span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">分散度</span>

当一种物质的微粒分散在另一种物质之中，就构成了分散系统，当分散在气体中的微粒为固体时，通常称为<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:烟尘<span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></span>
B:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">烟雾</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span>
C:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">粉尘</span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">烟</span>

中净化除尘器主要用于通风除尘系统，要求净化后的空气含尘浓度不超过<u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp; </span><span style="mso-spacerun: yes">&nbsp;</span><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></span></u>。<span lang="EN-US"><o:p></o:p></span>
A:1-2mg/m³<span style="mso-spacerun: yes">&nbsp; </span>
B:&nbsp;50<span style="mso-bookmark: OLE_LINK1"><span style="mso-bookmark: OLE_LINK2"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">&mdash;<span lang="EN-US">100 mg/m³&nbsp;<span style="mso-spacerun: yes">&nbsp;</span></span></span></span></span>
C:100&mdash;<span lang="EN-US">200 mg/m³<span style="mso-spacerun: yes">&nbsp;</span></span>
D:5-10 mg/m<u>³</u>

民用建筑大门<span class="GramE">空气幕常采用</span>的形式是<u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u>。<span lang="EN-US"><o:p></o:p></span>
A:<span class="GramE"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">单侧送式空气</span></span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">幕</span>
B:送式空气幕
C:<span class="GramE">下送式空气</span>幕
D:<span class="GramE">双侧送式空气</span>幕

在生产车间，当生产设备偶然事故或故障时，会突然散发大量有害气体或有爆炸性的气体，应设置<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">全面通风</span>
B:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">局部通风</span>
C:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">事故排风系统</span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">自然通风系统</span>

在<span class="GramE">不</span>设有组织自然通风的房间中，当机械进、排风量相等时，室内压力等于室外大气压力。当机械进风量小于机械排风量时，室内处于<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">状态。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">负压</span>
B:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">正压</span>
C:&nbsp;<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">大气压</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">零压</span>

造成粉尘进一步扩散，污染车间空气环境的主要原因是二次气流，即由通风或<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">所形成的室内气流。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">扩散</span>
B:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">沉降作用</span>
C:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">冷热气流对流</span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">离心力作用</span>

对于<span class="GramE">热过程</span>的通风柜，应将吸风口布设在通风柜的<u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span></u>，才能有效地控制有害物。<span lang="EN-US"><o:p></o:p></span>
A:&nbsp;<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">上部<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></span></span>
B:下部<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></span>
C:中间<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span>
D:上下均可

在有害物产生地<span class="GramE">点直接</span>将他们捕集起来，经过净化处理，排至室外，这种通风方法称为<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">局部通风</span>
B:<span class="GramE"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">全面通风</span></span>
C:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">自然通风</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp; </span></span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">稀释通风</span>

所谓<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">就是合理地布置送、排风口的位置、分配风量以及选用风口形式，以便用最小的通风量达到最佳的通风效果。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">通风方法</span>
B:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">局部通风</span>
C:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">气流组织</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span>
D:<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">全面通风</span>

选用除尘器时要注意风量变化对除尘器效率和阻力的影响，旋风除尘器的效率和阻力是随风量的增加而<u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u>的，电除尘器的效率是随风量的增加而<u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u>的。<span lang="EN-US"><o:p></o:p></span>
A:<span style="mso-bookmark: OLE_LINK1"><span style="mso-bookmark: OLE_LINK2"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">下降 下降</span></span></span>
B:增加<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp; </span></span>下降
C:增加<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp; </span></span>增加
D:下降<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp; </span></span>增加

为减小局部阻力，布置管道时，应尽量取直线，减少弯头。圆形风管弯头的曲率半径一般应大于<u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">管径。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span>
A:1<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">倍</span>
B:1~2<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">倍</span>
C:3<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">倍</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></span>
D:4<span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">倍</span>