熱(re)水供應系統(tong)的(de)安(an)裝(zhuang)(zhuang)技術要求與熱(re)水采暖(nuan)系統(tong)安(an)裝(zhuang)(zhuang)技術要求相同。用水點(dian)(dian)(又稱配水點(dian)(dian))多(duo)為衛生設(she)備,安(an)裝(zhuang)(zhuang)要求見給、排水、衛生設(she)備安(an)裝(zhuang)(zhuang)相關部(bu)分。
熱水供應(ying)系統所(suo)需設備如圖(tu)2-52所(suo)示(shi),主(zhu)要(yao)有循(xun)環水泵(beng)、補充(chong)水泵(beng)、冷水箱(xiang)、閉式膨脹水箱(xiang)、自(zi)動排(pai)氣閥、安全閥、水的加熱裝置等。
冷水(shui)(shui)(shui)(shui)(shui)(shui)箱(xiang)(xiang)可以采(cai)用(yong)(yong)熱(re)(re)水(shui)(shui)(shui)(shui)(shui)(shui)采(cai)暖(nuan)中(zhong)(zhong)的(de)(de)膨(peng)脹水(shui)(shui)(shui)(shui)(shui)(shui)箱(xiang)(xiang),并且還(huan)可斟(zhen)情(qing)省略一些管道,設(she)(she)(she)計(ji)和施(shi)工中(zhong)(zhong)可采(cai)用(yong)(yong)國(guo)際(ji)中(zhong)(zhong)有關水(shui)(shui)(shui)(shui)(shui)(shui)箱(xiang)(xiang)標準(zhun)圖(tu)(tu)。閉式膨(peng)脹水(shui)(shui)(shui)(shui)(shui)(shui)箱(xiang)(xiang)完全可以采(cai)用(yong)(yong)熱(re)(re)水(shui)(shui)(shui)(shui)(shui)(shui)采(cai)暖(nuan)系統(tong)(tong)中(zhong)(zhong)低位膨(peng)脹水(shui)(shui)(shui)(shui)(shui)(shui)箱(xiang)(xiang),該裝置接(jie)人(ren)系統(tong)(tong)后如圖(tu)(tu)2-52(b)所示,啟動補(bu)水(shui)(shui)(shui)(shui)(shui)(shui)泵,水(shui)(shui)(shui)(shui)(shui)(shui)被送(song)入管網時(shi)(shi),也同時(shi)(shi)送(song)入罐體膠(jiao)(jiao)囊(nang)(nang)內(nei)(nei)(nei),在運行壓(ya)(ya)(ya)力(li)(li)(li)(li)較(jiao)低時(shi)(shi)(即(ji)系統(tong)(tong)用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)較(jiao)多、水(shui)(shui)(shui)(shui)(shui)(shui)位下降),補(bu)水(shui)(shui)(shui)(shui)(shui)(shui)泵把水(shui)(shui)(shui)(shui)(shui)(shui)不斷送(song)入系統(tong)(tong)并送(song)入膠(jiao)(jiao)囊(nang)(nang)內(nei)(nei)(nei),膠(jiao)(jiao)囊(nang)(nang)不斷向外擴大而擠(ji)壓(ya)(ya)(ya)氣(qi)(qi)室(shi)(shi),氣(qi)(qi)室(shi)(shi)的(de)(de)縮(suo)小使壓(ya)(ya)(ya)力(li)(li)(li)(li)升高(gao),當(dang)壓(ya)(ya)(ya)力(li)(li)(li)(li)達到(dao)(dao)設(she)(she)(she)計(ji)最(zui)高(gao)壓(ya)(ya)(ya)力(li)(li)(li)(li)時(shi)(shi),膠(jiao)(jiao)囊(nang)(nang)內(nei)(nei)(nei)的(de)(de)容水(shui)(shui)(shui)(shui)(shui)(shui)量達到(dao)(dao)設(she)(she)(she)計(ji)值,此時(shi)(shi)膠(jiao)(jiao)囊(nang)(nang)內(nei)(nei)(nei)外壓(ya)(ya)(ya)力(li)(li)(li)(li)相等,膠(jiao)(jiao)囊(nang)(nang)不脹不縮(suo),處于暫(zan)時(shi)(shi)平衡(heng)狀態。補(bu)水(shui)(shui)(shui)(shui)(shui)(shui)泵通(tong)過壓(ya)(ya)(ya)力(li)(li)(li)(li)控(kong)制器而停運。水(shui)(shui)(shui)(shui)(shui)(shui)泵停運后,氣(qi)(qi)室(shi)(shi)中(zhong)(zhong)氣(qi)(qi)體壓(ya)(ya)(ya)力(li)(li)(li)(li)擠(ji)壓(ya)(ya)(ya)膠(jiao)(jiao)囊(nang)(nang),使膠(jiao)(jiao)囊(nang)(nang)內(nei)(nei)(nei)的(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)流人(ren)系統(tong)(tong),氣(qi)(qi)室(shi)(shi)壓(ya)(ya)(ya)力(li)(li)(li)(li)也隨之減小,當(dang)氣(qi)(qi)壓(ya)(ya)(ya)降到(dao)(dao)設(she)(she)(she)計(ji)最(zui)低壓(ya)(ya)(ya)力(li)(li)(li)(li)時(shi)(shi),通(tong)過壓(ya)(ya)(ya)力(li)(li)(li)(li)控(kong)制器啟動水(shui)(shui)(shui)(shui)(shui)(shui)泵,又(you)使水(shui)(shui)(shui)(shui)(shui)(shui)送(song)進(jin)系統(tong)(tong)和膠(jiao)(jiao)囊(nang)(nang),這(zhe)就既保證了用(yong)(yong)戶(hu)供(gong)熱(re)(re)水(shui)(shui)(shui)(shui)(shui)(shui)(或供(gong)冷水(shui)(shui)(shui)(shui)(shui)(shui))的(de)(de)需(xu)要,又(you)使水(shui)(shui)(shui)(shui)(shui)(shui)泵有條件地間斷工作,節約了電(dian)能(neng)。目前已成為熱(re)(re)水(shui)(shui)(shui)(shui)(shui)(shui)供(gong)應系統(tong)(tong)或無(wu)塔供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)常用(yong)(yong)設(she)(she)(she)備。其規格見表2-24。
水(shui)(shui)(shui)的(de)(de)加熱設備是熱水(shui)(shui)(shui)供應的(de)(de)熱源部分,又稱(cheng)(cheng)加熱器(qi)(qi)(qi)(qi)。根(gen)據系統范圍(wei)大小可采用水(shui)(shui)(shui)-水(shui)(shui)(shui)熱交換器(qi)(qi)(qi)(qi)、汽一水(shui)(shui)(shui)熱交換器(qi)(qi)(qi)(qi)、電(dian)熱水(shui)(shui)(shui)器(qi)(qi)(qi)(qi)、燃氣(qi)熱水(shui)(shui)(shui)器(qi)(qi)(qi)(qi)、太(tai)陽能熱水(shui)(shui)(shui)器(qi)(qi)(qi)(qi)等多種。如要(yao)求這些熱水(shui)(shui)(shui)器(qi)(qi)(qi)(qi)不僅起加熱作用,還要(yao)有貯存和調節(jie)水(shui)(shui)(shui)量的(de)(de)功(gong)能,就必(bi)須有一定的(de)(de)盛水(shui)(shui)(shui)體積,這種加熱器(qi)(qi)(qi)(qi)稱(cheng)(cheng)為(wei)容積式(shi),對于只起加熱稱(cheng)(cheng)為(wei)快速式(shi)。
容積(ji)(ji)式加熱(re)器的結(jie)構如(ru)圖2-52所示(shi),由罐(guan)(guan)體、盤(pan)管等組成。盤(pan)管內送人高溫(wen)(wen)熱(re)水(shui)或蒸汽(qi),將熱(re)量通過(guo)盤(pan)管表(biao)面(mian)積(ji)(ji)傳給冷水(shui)。罐(guan)(guan)體由支座(zuo)直接用地(di)腳螺栓固定在地(di)基上,高溫(wen)(wen)熱(re)水(shui)或蒸汽(qi)通過(guo)管道與加熱(re)器相連接。采用蒸汽(qi)加熱(re)時(shi)其(qi)蒸汽(qi)凝結(jie)水(shui)出口還要(yao)連接疏水(shui)閥(fa)等附件。
板式換熱器是應用最多的非容積式加熱器,廣泛用于采暖和熱水供應的換熱上。板式換熱器的結構為框架式,如圖2-53所示。框架由固定壓緊板、上導梁、下導梁和支柱組成。活動壓緊板通過滾輪懸掛在上導梁上,傳熱板片置于固定壓緊板與活動壓緊板之間,大型板式換熱器的傳熱片是用掛鉤掛在上導梁上,上部卡在下導梁上。傳熱板是用0.8mm厚的不銹鋼板壓制成雙人字形波紋板片,四角沖制圓孔洞。板片四周及圓孔處均鑲嵌有密封橡膠墊起密封作用。組裝時傳熱板片相互倒置排列,使傳熱板片上波紋的波峰與波峰間互相接觸形成網狀流道,既強化了傳熱又增加了傳熱板的剛度,同時提高了板式換熱器的承壓能力。傳熱板通過夾緊螺栓,并按照組裝尺寸要求(或傳熱面積一片數),夾緊固定壓緊板和活動壓緊板之間。固定壓緊板和活動壓緊板的四角根據工藝的需要均設孔洞,并裝有與外部管道連接用的帶法蘭的短管,與傳熱片組裝在一起,構成了供冷熱介質流動的通道。圖2-54給出了傳熱板片并聯流程組合流程圖,每兩張傳熱板片間就構成一個流道,冷熱介質交替地流過傳熱板片,同時熱量通過傳熱板片由熱介質傳給了冷介質。由于雙人字形傳熱板片的結構特性所決定,介質在傳熱板片流動時,在低流速下即可激發湍流,使冷熱介質進行強烈地熱交換,因此板式換熱器與其他換熱器相比,具有較高的傳熱系數。根據冷介質的出口溫度要求,流程可以組成串聯、并聯、混合等多種形式,在設計時提出要求,生產企業按要求進行組裝供貨。
板式換熱器豎直地(di)用(yong)地(di)腳(jiao)螺栓固定(ding)在混凝土地(di)坪(ping)上(shang),四周留(liu)有一定(ding)距(ju)離(li),以便(bian)于(yu)管(guan)道(dao)、附(fu)件的安(an)裝及(ji)設備的檢修。換熱器使用(yong)前應對(dui)熱側、冷側分別進行水(shui)壓試驗,其試驗壓力為(wei)設計壓力的1.25倍(bei),并保壓20min,確認各(ge)密(mi)封部位無滲漏后方可投入使用(yong)。
在(zai)作(zuo)采(cai)暖(nuan)時,循環(huan)水(shui)進出(chu)口均裝壓(ya)力表(biao),在(zai)使(shi)用(yong)中若(ruo)壓(ya)降增大(da)說明內部產(chan)生(sheng)結垢淤塞,此時應松開(kai)夾緊螺栓,移動活動壓(ya)緊板(ban),然后進行清洗(xi)。清洗(xi)板(ban)片(pian)(pian)時要用(yong)棕刷,切勿用(yong)鋼絲刷,以(yi)免(mian)劃(hua)傷板(ban)片(pian)(pian)和(he)橡膠墊。損(sun)壞的板(ban)片(pian)(pian)要更換,若(ruo)沒有備用(yong)板(ban)片(pian)(pian),可拆下兩個相(xiang)鄰的板(ban)片(pian)(pian),然后夾緊使(shi)用(yong)。
特別提醒:老(lao)化(hua)的密封橡膠(jiao)墊要及時更新,要把板(ban)片的密封槽(cao)清洗干凈后(hou)涂粘結(jie)劑,再把密封膠(jiao)墊鑲(xiang)嵌在密封槽(cao)內。
在實際工程中,使用蒸汽直接與冷水混合產生熱水的方法也比較普遍,這種方法簡單、投資小、維修方便,但噪聲大,冷凝水不能回收利用。常用的方法有多孔管放在水箱內,送入蒸汽,蒸汽從小孔中噴出與水混合,也可采用專用的汽水混合加熱器,其構造如圖2-55所示。在外殼內裝有錐形管,管壁上布滿小孔,冷水在流動中與蒸汽在錐形管內混合,適用于具有蒸汽熱源的熱水采暖系統與熱水供應系統,同時隨熱負荷的改變,調整蒸汽閥門的開啟度即可實現溫度調節。該國標圖集供、回水溫差大小分為25℃、40℃、60℃三種型號按噴管喉口直徑大小分為6、8、10、12、14、16、18、20、25、30、35、40、50、60、70(mm)共15個型號。供熱水和采暖系統管道連接方式如圖2-56、圖2-57所示。為防止供水溫度過熱,在蒸汽管道入口設置溫度自動控制系統,如安裝自力式溫度調節閥。為防止系統水倒灌入蒸汽系統中,在蒸汽管路上安裝逆止閥。