北海街道機械密封包括壓力控制、溫度控制、流體替換(堵塞)和雜質去除系統。在北海街道機械密封系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)中(zhong)，上述系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)并不同時包括在(zai)(zai)內。密(mi)封(feng)(feng)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)選擇主(zhu)(zhu)(zhu)要取決于(yu)主(zhu)(zhu)(zhu)密(mi)封(feng)(feng)件的(de)應用(yong)(yong)范圍(wei)。例如(ru)(ru)(ru)，如(ru)(ru)(ru)果主(zhu)(zhu)(zhu)密(mi)封(feng)(feng)用(yong)(yong)于(yu)高溫(wen)(wen)液體(ti)，密(mi)封(feng)(feng)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)應確(que)保(bao)降低(di)主(zhu)(zhu)(zhu)密(mi)封(feng)(feng)的(de)環(huan)境溫(wen)(wen)度，即(ji)采用(yong)(yong)溫(wen)(wen)度控制(zhi)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)。如(ru)(ru)(ru)果主(zhu)(zhu)(zhu)密(mi)封(feng)(feng)用(yong)(yong)于(yu)固(gu)體(ti)雜質含量高的(de)工作介(jie)(jie)質，密(mi)封(feng)(feng)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)應確(que)保(bao)在(zai)(zai)主(zhu)(zhu)(zhu)密(mi)封(feng)(feng)前降低(di)固(gu)體(ti)雜質含量，即(ji)采用(yong)(yong)除雜系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)。在(zai)(zai)腐(fu)(fu)蝕性介(jie)(jie)質中(zhong)，密(mi)封(feng)(feng)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)必(bi)須確(que)保(bao)主(zhu)(zhu)(zhu)密(mi)封(feng)(feng)降低(di)腐(fu)(fu)蝕速率或消(xiao)除腐(fu)(fu)蝕，即(ji)使(shi)用(yong)(yong)流(liu)(liu)體(ti)而不是堵塞流(liu)(liu)體(ti)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)；在(zai)(zai)高壓密(mi)封(feng)(feng)裝置中(zhong)，輔助系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)應確(que)保(bao)多級降壓和其他措(cuo)施，即(ji)壓力控制(zhi)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)。

　　北海街道機械密封的三個主要功能如下：

　　1、沖洗功能，沖洗是北海街道機械密封基本的功能，它直接將液體注入單面密封或雙面密封的高壓側。一般的北海街道機械密封應該沖(chong)洗(xi)，特(te)別是對于輕(qing)烴泵(beng)，沖(chong)洗(xi)時達到隔(ge)離(li)介(jie)質、冷(leng)卻和改(gai)善潤滑的目(mu)(mu)的。隔(ge)離(li)介(jie)質的目(mu)(mu)的可(ke)以(yi)通過(guo)將與介(jie)質相容的液體引入(ru)密封腔進行外部循環沖(chong)洗(xi)來(lai)實(shi)現。

　　2、除雜和過濾功能，密封流體中的微細固體粒子、污垢等雜質對北海街道機械密封造成的(de)危害(hai)非(fei)常嚴重，可能導致密(mi)(mi)(mi)(mi)封(feng)端面的(de)磨(mo)損，也可能堵塞寒冷密(mi)(mi)(mi)(mi)封(feng)系統的(de)管線。密(mi)(mi)(mi)(mi)封(feng)性(xing)系統軟件具有去除殘(can)渣、保(bao)持(chi)液(ye)體(ti)(ti)(ti)清(qing)潔的(de)作用(yong)(yong)。當殘(can)渣的(de)相(xiang)對(dui)(dui)密(mi)(mi)(mi)(mi)度小于液(ye)體(ti)(ti)(ti)媒質相(xiang)對(dui)(dui)密(mi)(mi)(mi)(mi)度時(shi)，能用(yong)(yong)過(guo)濾裝置去除殘(can)渣；而(er)當殘(can)渣的(de)相(xiang)對(dui)(dui)密(mi)(mi)(mi)(mi)度超過(guo)液(ye)體(ti)(ti)(ti)媒質相(xiang)對(dui)(dui)密(mi)(mi)(mi)(mi)度時(shi)，可選用(yong)(yong)旋(xuan)液(ye)分離設(she)備或網式(shi)過(guo)濾器去除殘(can)渣。

　　3、流體替代功能，含有固體顆粒的氣相介質和液相介質的直接密封難度很大，它們溫、毒、貴、易蒸發、易結晶。借助北海街道機械密封可以用雙端北海街道機械密封代替密(mi)封介(jie)質(zhi)，將難以直(zhi)接密(mi)封的介(jie)質(zhi)轉化為密(mi)封潤滑性能好、清潔的密(mi)封液(ye)體介(jie)質(zhi)。