介(jie)(jie)質(zhi)過濾(lv)(lv)器事實(shi)上(shang),以三(san)層(ceng)(ceng)(ceng)(ceng)(ceng)(ceng)濾(lv)(lv)床(chuang)為例,上(shang)層(ceng)(ceng)(ceng)(ceng)(ceng)(ceng)濾(lv)(lv)料(liao)(liao)粒徑較大,有(you)密(mi)度(du)(du)小(xiao)的(de)(de)(de)(de)(de)(de)輕質(zhi)濾(lv)(lv)料(liao)(liao)組成,如無(wu)煙(yan)煤、活(huo)性(xing)炭(tan);中(zhong)層(ceng)(ceng)(ceng)(ceng)(ceng)(ceng)濾(lv)(lv)料(liao)(liao)粒徑居中(zhong),密(mi)度(du)(du)居中(zhong),一般為石(shi)英砂組成;下(xia)層(ceng)(ceng)(ceng)(ceng)(ceng)(ceng)濾(lv)(lv)料(liao)(liao)由粒徑較小(xiao),密(mi)度(du)(du)較大的(de)(de)(de)(de)(de)(de)重質(zhi)濾(lv)(lv)料(liao)(liao)組成,如磁(ci)鐵礦。由于密(mi)度(du)(du)的(de)(de)(de)(de)(de)(de)限(xian)制(zhi),三(san)層(ceng)(ceng)(ceng)(ceng)(ceng)(ceng)介(jie)(jie)質(zhi)過濾(lv)(lv)器的(de)(de)(de)(de)(de)(de)濾(lv)(lv)料(liao)(liao)選擇基(ji)本上(shang)是固(gu)定(ding)的(de)(de)(de)(de)(de)(de)。上(shang)層(ceng)(ceng)(ceng)(ceng)(ceng)(ceng)濾(lv)(lv)料(liao)(liao)起粗(cu)濾(lv)(lv)作(zuo)(zuo)用(yong),下(xia)層(ceng)(ceng)(ceng)(ceng)(ceng)(ceng)濾(lv)(lv)料(liao)(liao)起精濾(lv)(lv)作(zuo)(zuo)用(yong),這(zhe)樣就(jiu)充分發(fa)揮(hui)了多(duo)介(jie)(jie)質(zhi)濾(lv)(lv)床(chuang)的(de)(de)(de)(de)(de)(de)作(zuo)(zuo)用(yong)。
而(er)對于飲(yin)用水(shui),一般禁止(zhi)使(shi)用無煙煤,樹脂(zhi)等濾料。