液體過濾系統

如何挑選適合您的過濾？
-----過濾機理
液體從過濾袋內流向袋外，濾出的顆粒被截留在袋內，使袋式過濾的工作原理是壓力過濾。整套袋式過濾系統包括三個部分：過濾容器、支撐網籃和過濾袋。
要過濾的液體從被支撐網籃支撐的過濾袋頂部注入，這使得液體在過濾表面均勻分布，以便整個介質中流動分布是一致的面，沒有紊流的負效應。
液體從過濾袋內流向袋外，濾出的顆粒被截留在袋內，使得更換過濾袋時不致污染已經過濾的液體。在過濾袋內的提手設計使得過濾袋更換快速便捷。
上海贏森濾袋特點如下：
高流通能力. 
較長濾袋使用壽命. 
均勻的流動液體令顆粒雜質平均地分布在濾袋的濾層中
較高的過濾效率,成本最低. 
1.濾材的選用
首先按照所要過濾的流體化學名稱，依化學配合禁忌找出可用的濾材，再針對其操作溫度，操作壓力，酸堿值，操作條件(如，是否須要耐受蒸汽，熱水或化學品殺菌等)，逐一評估，并剔除不適用之濾材。 用途也是一個重要的考慮因素，比方藥品、食品或化妝品用之濾材必須是FDA準許的材質；超純水則須挑選純凈、不含有釋出物會影響比阻抗的濾材；過濾氣體則須挑選疏水性材質以及是否需要"衛生級過濾"設計等等。
2.過濾精密度
這是一個最令人困擾的問題。比方，要除去肉眼可見的顆粒，要選用25微米過濾器；要除去液體中云狀物，要選用1或5微米過濾器；要濾除最小的細菌則需0.2微米的過濾器。問題在于有兩種過濾精度單位：絕對精度／公稱精度.
絕對精度／公稱精度
絕對精度是指能100%濾除所標示精度之顆粒。對任何一種過濾器而言，這幾乎是一個不可能達到，而且不實際的標準，因為100%是一個無窮大的值。市面上通稱的絕對過濾器如薄膜等，嚴格地說，只能稱"趨近于絕對"的過濾器,而其它則皆屬于公稱精度，公稱精度，這才是主要的困擾所在:"公稱精度并沒有一個業者共同認定并遵行的標準"。也就是說甲公司可以把公稱精度訂在85-95%，而乙公司卻寧可訂在50-70%。換句話說，甲公司的25微米過濾精度可能等于乙公司的5微米，或者更細。對此問題，有經驗的專業過濾器供應商會有助于過濾精度之選擇，而根本解決之道是"試用"。
3. 依照過濾溫度時的粘度，專業過濾設備供應商可以計算出需要多大的過濾器，濾袋承擔多大的流速以及預測其初期壓降若干。若能提供流體中雜質含量，甚至可以預估其過濾壽命。
4. 過濾系統之設計 
　這個標題牽涉范圍較廣，比方應該選用那一種壓力來源，需要多大的壓力，是否需要裝兩套過濾器并聯，以適合連續性操作之系統，對粒徑分布寬廣的場合應如何搭配粗濾與精濾，系統中是否須要裝逆止閥或其他裝置等等。這些都需要使用單位與過濾器供應商密切配合，共同找出最恰當的設計。
5. 濾袋的使用方式 
濾器密閉過濾：濾袋與配套過濾器同時使用，利用系統流體壓力，將液體擠壓通過濾袋，以達到過濾的目的。具有流速快，處理能力大，濾袋使用壽命長的優點，特別適應大流量需密閉過濾的場合。自流開放過濾：濾袋通過適合接頭直接與管道相連，得用流體重力壓差進行過濾。其顯著特點是無需設備投資，過濾簡單可行，特別適用于小規格、多品種、間歇式的經濟型液體過濾。
表面過濾與深度過濾的區別
表面過濾主要采用篩網材料，深度過濾則采用毛氈材料，它們的區別如下：
1．篩網材料（尼龍單絲、金屬單絲）將過濾中雜質直接截留在材料表面。優點是單絲結構可反復清洗，消耗成本較低；而缺點是表面過濾模式，易造成濾袋表面堵塞，該類型產品最適用于精度較低的粗濾場合，過濾精度25-1200μm。
2．毛氈材料（針刺布、溶吹無紡布）是常見的深層三維過濾材料，其特點是纖維組織疏松，高空隙率增加了雜質的容截量，該種纖維材料系屬復式截留模式，即較大的顆粒雜質被截留在纖維表面，而細微顆粒則被捕捉于濾材深層中，因此過濾具有較高過濾效率，此外高溫表面熱處理，即應用瞬間燒結技術，能有效地防止過濾時纖維受流體高速沖帶而散失；毛氈材料是屬于丟棄型的（一次性使用），過濾精度1-200μm。
過濾氈主要使用的材質性能如下：
聚脂--最普遍使用的濾材纖維，抗化學品佳，工作溫度小于170-190℃
聚丙烯--用于化學工業的液體過濾，有極佳的抗酸、堿功能，工作溫度小于100-110℃
羊毛--很好的抗溶劑功能，但不適用于抗酸、堿的過濾 
尼龍--有良好抗化學品功能（除抗酸以外），工作溫度小于170-190℃ 
氟化物--具有******的抗溫及抗化學品功能，工作溫度小于250-270℃ 

How to select the filtration fit for your application
Principles of filtration
Liquid goes through the filter bag, particulars are trapped in the bag, the principles of the filter is pressure filtration. The bag type filtration system has filter container, support net basket and filter bag.
Liquid for filtration is feed from the top and evenly distributed in the filtration surface, the movement of the medium is at uniformed side, non negative effect of vortex flow. 
The particulars are trapped in the bag, and will not containment the filtered liquid while replacing the filter bag. 
Featurres: 
High flow capability. 
Long life time of the filter bag. 
Evenly distributed particulars in the filtration layer of the bag 
High filtration effect, low cost. 
1.Selection of filtration material
Select the applicable filtration material based upon the chemical nomination of the fluid chemical and the chemical composition; secondly, judged by the operating temperature, operating pressure, acid & caustic values, operating conditions (such as steam durable, hot water or chemical anti-bacteria etc) rejecting the non suitable filtration material. The usage is another important factor, such as medicine, food or cosmetics filtration material must be FDA compliance material. Filtration material used in the pure water must be purified, non releasing material which may impact the anti-resistance , air filtration must be hydro water material and whether need hygiene filtration design etc
2.Filtration mesh and density
This has been an annoying issue. For example, to remove the seeable particulars may need 25 um filter, to remove the cloudy material in the liquid may need 1 to 5 um filter, and 0.2 um filter may be required to remove micro bactria.
Absolute precise / nominated precises This has been an annoying issue. For example, to remove the seeable particulars may need 25 um filter, to remove the cloudy material in the liquid may need 1 to 5 um filter, and 0.2 um filter may be required to remove micro bactria.absolute precise / nominated precises.
Absolute precise refer to 100% remove the indicated sized particulars. It is impossible and not feasible for every filter , since 100% is an infinite value. The absolute filter such as films in the market is actually close to the absolute filter. The issue for the nominated precise is that there is no common recognized and executable standard. For instance, company A may defines as 85-95%, company B may defines as 50-70%. In another word, the 25 um filter of company A may equals to 5 um filter of company B. Experience filter supplier can help to determine the most suitable filter, and most effective way is “try use”
3. Filter supplier can calculate the size of the filter based upon the flow speed that bag can bear, and estimation of primary pressure drop and viscosity at filtration temperature. The estimated life time can be made if the content of foreign material in the fluid is known.
4. Design of filtration system 
This may involve various aspects, such as the selection of pressure source, pressure range, whether two sets of filters should be parallel to assist continuous operation. The coarse filtration and fine filtration matching, whether check valve or other facilities shall be equipped in the system. All of above shall be communicated with the filter supplier to get most appropriate design.
5. Way of filter bag use  
Close filtration in filter: filter bag is used with the filter, liquid is squeezed pass through the filter bag via system fluid pressure and filtration is achieved. Such application has the advantage of rapid fluid speed and high capacity, long life cycle of the filter bag. And mostly suitable for high flow closed loop filtration application.
Difference between surface filtration and deep filtration：
1. Sieve (nylon single filament, non ferrous steel single filament) The foreign material in the filtration process trapped on the material surface. The advantage is the filtration net can be reused after using and low consumption cost. The disadvantage is of surface filtration, which easy to cause surface block. Such type of sieve is suitable for coarse filtration application, the sieve mesh is 25-1200μm
2．Acicular blanket can effectively remove solids and soft particulars. The acicular 100% pure fiber has the multi dimensional structure and purred filtering layers, especially the internal layer has the pure fiber high strength net to prevent the filter bag from damage and abrasion due to the pressure increase.
The major property of the filter blanket is as follow:
Polyester -The conventional filtration fiber, ideal for anti-chemical contamination, working temperature below 70-190
Polypropylene –Used for liquid filtration in chemical industry, have good anti-acid and anti-caustic, working temperature lower 100-110
Wool-good anti-solvency , but applicable for anti-acid, anti-caustic filtration
Nylon—satisfactory anti-chemical (except acid), working temperature lower than 170-190
Fluorin—have good anti-heating and anti-chemical property, working temperature lower than 250-270.