下图是一聚合釜温度控制系统,试问:1) 这是一个什么类型的控制系统？请画出其方块图； 2) 若釜内的温度不允许过高，否则易发生事故，试确定阀的气开气关形式及主副调节器的正反作用； 3)简述当干扰使釜内温度升高时的控制过程；4)若冷却水的温度是经常波动的，上述系统应如何改进，请画出控制流程图。

<p class="MsoNormal"><span style="font-size:14.0pt;font-family:宋体;mso-ascii-font-family: &quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;">１）串级控制系统，方框图如下：</span><span lang="EN-US" style="font-size:14.0pt"><o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:宋体;mso-ascii-font-family: &quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;"><img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1539567329438b13ce30dccd2405499a71bc4ab6f29d1.png" alt="上传图片"><br></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:宋体;mso-ascii-font-family: &quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;">２）从安全角度出发，釜内温度不允许过高，信号中断时，调节阀应处于全开位置安全，所以应选择气关阀。</span><span lang="EN-US" style="font-size:14.0pt"><o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:宋体;mso-ascii-font-family: &quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;">　因为阀选择气关，则</span><span lang="EN-US" style="font-size:14.0pt">kv</span><span style="font-size:14.0pt; font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family: &quot;Times New Roman&quot;">选“－”，冷却水流量增大时，则</span><span lang="EN-US" style="font-size: 14.0pt">F</span><span style="font-size:14.0pt;font-family:宋体;mso-ascii-font-family: &quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;">增大，ｋｐ２选“＋”，根据负反馈原则，则ｋｃ２应为“＋”，所以流量控制器应选择反作用。</span><span lang="EN-US" style="font-size:14.0pt"><o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:宋体;mso-ascii-font-family: &quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;">当</span><span lang="EN-US" style="font-size:14.0pt">F</span><span style="font-size:14.0pt; font-family:宋体;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family: &quot;Times New Roman&quot;">增大时，釜内温度下降，ｋｐ１选“－”，则ｋｃ１选“＋”，所以温度控制器应选择正作用。</span><span lang="EN-US" style="font-size:14.0pt"><o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:宋体;mso-ascii-font-family: &quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;">３）当温度</span><span lang="EN-US" style="font-size:14.0pt">T</span><span style="font-size:14.0pt; font-family:宋体">↑→</span><span style="font-size:14.0pt;font-family:宋体; mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;">温度变送器输出</span><span style="font-size:14.0pt;font-family:宋体">↑－<span lang="EN-US">&gt;</span>Ｔｃ的输入信号↑（Ｔｃ是正作用调节器），—<span lang="EN-US">&gt;Tc</span>的输出↑，—<span lang="EN-US">&gt;</span>流量调节器的给定值↑（相当于给定值不变，测量值↓，Ｆｃ是正作用调节器）—<span lang="EN-US">&gt;</span>Ｆｃ的输出↓（阀为气关阀）—<span lang="EN-US">&gt;</span>阀的开度↑—<span lang="EN-US">&gt;</span>冷却水流量↑—<span lang="EN-US">&gt;</span>夹套水温度↓—<span lang="EN-US">&gt;</span>釜内温度Ｔ↓。<span lang="EN-US"><o:p></o:p></span></span></p><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:宋体">４）若冷却水温度经常变动，则系统的副变量应选夹套水的温度，以冷却水的进水量作为操纵变量。<span lang="EN-US"><o:p></o:p></span></span></p>