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倒流(liu)防止器是如何保證用水安全的

　　理(li)論上城市自來水(shui)(shui)供水(shui)(shui)水(shui)(shui)質(zhi)均達到了(le)(le)國家飲(yin)用水(shui)(shui)標準，滿足生(sheng)活飲(yin)用水(shui)(shui)水(shui)(shui)質(zhi)要求，但是在管(guan)(guan)道(dao)輸(shu)送的過程(cheng)中(zhong)，卻(que)易受到意外(wai)污(wu)染(ran)。如管(guan)(guan)道(dao)銹蝕、管(guan)(guan)材(cai)選(xuan)用不當(dang)、建筑(zhu)內管(guan)(guan)道(dao)與市政管(guan)(guan)道(dao)連接(jie)沒有采取(qu)適當(dang)的防(fang)護(hu)措施等。為保證居民生(sheng)活用水(shui)(shui)的衛生(sheng)與安全，必須防(fang)止小區供水(shui)(shui)管(guan)(guan)網(wang)水(shui)(shui)質(zhi)二次(ci)污(wu)染(ran)。倒(dao)流防(fang)止器除了(le)(le)嚴(yan)格治理(li)水(shui)(shui)環境污(wu)染(ran)、改進(jin)凈水(shui)(shui)工藝(yi)、提高出廠水(shui)(shui)質(zhi)、嚴(yan)控(kong)輸(shu)水(shui)(shui)管(guan)(guan)網(wang)本身(shen)污(wu)染(ran)以及優化管(guan)(guan)材(cai)外(wai)，還須根除管(guan)(guan)網(wang)交(jiao)叉連接(jie)引起(qi)的倒(dao)流污(wu)染(ran)，消除二次(ci)污(wu)染(ran)源(yuan)。

倒流防(fang)(fang)止(zhi)器(qi)（Backflow preventers）是保證(zheng)用水(shui)(shui)安(an)全、防(fang)(fang)止(zhi)管(guan)(guan)網交(jiao)叉連(lian)接(jie)引(yin)起的(de)(de)(de)水(shui)(shui)質二次污(wu)染(ran)的(de)(de)(de)有效措施。倒流防(fang)(fang)止(zhi)器(qi)主要特點是嚴格限制管(guan)(guan)道(dao)中水(shui)(shui)的(de)(de)(de)單(dan)向(xiang)流動流，在任(ren)何(he)工(gong)況下防(fang)(fang)止(zhi)管(guan)(guan)道(dao)中水(shui)(shui)的(de)(de)(de)倒流。從而徹(che)底防(fang)(fang)止(zhi)了倒流流污(wu)染(ran)，保證(zheng)用水(shui)(shui)的(de)(de)(de)衛(wei)生、安(an)全。

交(jiao)叉連(lian)接(jie)和(he)倒(dao)(dao)流(liu)(liu)污(wu)染(ran)(ran) 交(jiao)叉連(lian)接(jie)：根據美國 AWWA（美國水(shui)(shui)(shui)(shui)(shui)工協會(hui)(hui)）的定義，在(zai)飲(yin)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)給水(shui)(shui)(shui)(shui)(shui)系統中，凡用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)終(zhong)端到飲(yin)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)管(guan)(guan)道(dao)接(jie)入點(dian)之間管(guan)(guan)路，皆稱為“交(jiao)叉連(lian)接(jie)”。非(fei)生(sheng)活(huo)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)管(guan)(guan)道(dao)，或(huo)(huo)因(yin)長期不用(yong)(yong)(yong)(yong)而使水(shui)(shui)(shui)(shui)(shui)變質（如(ru)消防管(guan)(guan)網(wang)），或(huo)(huo)因(yin)配水(shui)(shui)(shui)(shui)(shui)出口極(ji)易玷(dian)污(wu)（如(ru)游泳池，冷卻(que)塔等），它們對管(guan)(guan)網(wang)的水(shui)(shui)(shui)(shui)(shui)質構成嚴重威脅，一(yi)旦產生(sheng)倒(dao)(dao)流(liu)(liu)，生(sheng)活(huo)飲(yin)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)管(guan)(guan)網(wang)就會(hui)(hui)被嚴重污(wu)染(ran)(ran)。倒(dao)(dao)流(liu)(liu)污(wu)染(ran)(ran)：由于用(yong)(yong)(yong)(yong)戶端管(guan)(guan)路壓力升高或(huo)(huo)市(shi)(shi)政供(gong)(gong)水(shui)(shui)(shui)(shui)(shui)壓力降低等原因(yin)，均會(hui)(hui)產生(sheng)“壓力倒(dao)(dao)流(liu)(liu)或(huo)(huo)者虹(hong)吸倒(dao)(dao)流(liu)(liu)”現(xian)象(xiang)，造成倒(dao)(dao)流(liu)(liu)水(shui)(shui)(shui)(shui)(shui)通過“交(jiao)叉連(lian)接(jie)”返回市(shi)(shi)政管(guan)(guan)網(wang)，引發(fa)倒(dao)(dao)流(liu)(liu)污(wu)染(ran)(ran)事(shi)故(gu)，嚴重威脅人(ren)民(min)的身體健康和(he)供(gong)(gong)水(shui)(shui)(shui)(shui)(shui)安全。

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