消(xiao)聲(sheng)(sheng)(sheng)器(qi)（圖4-62）通(tong)常用于介(jie)質(zhi)放空(kong)(kong)管的(de)(de)終端，以消(xiao)除可能因高壓高速介(jie)質(zhi)的(de)(de)放空(kong)(kong)而產(chan)生的(de)(de)噪(zao)聲(sheng)(sheng)(sheng)。通(tong)常包括蒸汽排(pai)氣(qi)(qi)消(xiao)聲(sheng)(sheng)(sheng)器(qi)、氣(qi)(qi)體排(pai)空(kong)(kong)消(xiao)聲(sheng)(sheng)(sheng)器(qi)、油浴(yu)式消(xiao)聲(sheng)(sheng)(sheng)過濾器(qi)、電機消(xiao)聲(sheng)(sheng)(sheng)器(qi)等。

  視鏡（圖(tu)4-63）通(tong)常用(yong)于(yu)冷(leng)卻水(shui)管(guan)(guan)道和(he)潤(run)滑(hua)油(you)(you)管(guan)(guan)道等(deng)，通(tong)過其(qi)透明的視窗可以觀察到(dao)管(guan)(guan)道內循環(huan)冷(leng)卻水(shui)或潤(run)滑(hua)油(you)(you)是否在(zai)流動。