板框過濾布目數選擇與微米對照說明

板框過濾布廣泛應用于：
? 鎳精礦
? 銅精礦
? 污泥脫水
? 冶金行業
? 化工行業

在實際選型過程中，客戶普遍習慣使用“目數”作為過濾精度的判斷依據。

一、什么是目數（Mesh）？

**目數（Mesh）**是指：

每英寸（25.4mm）長度內的孔數

目數與過濾精度關系如下：
? 目數越大 → 孔徑越小 → 過濾越精細
? 目數越小 → 孔徑越大 → 過濾通透性越強

二、常見目數與微米對照參考

根據行業通用篩網目數—微米對照表，部分常用參數如下：

目數（Mesh） 孔徑（μm）
60目 246μm
80目 198μm
100目 165μm
110目 150μm
180目 83μm
200目 74μm
250目 61μm
270目 53μm
325目 47μm
425目 33μm
500目 25μm
625目 20μm
800目 15μm

可以看到：
? 100目 ≈ 165微米（中等過濾）
? 200目 ≈ 74微米（精細過濾）
? 500目 ≈ 25微米（高精度過濾）
? 800目 ≈ 15微米（超精細過濾）

在板框壓濾應用中，常見目數一般在 100目—800目 之間。

三、不同工況如何選擇目數？

目數選擇需要結合以下因素：

1?? 物料粒徑
? 粗顆粒 → 100–150目
? 中等顆粒 → 150–300目
? 細顆?；蚋咭?→ 300目以上

2?? 過濾速度要求
? 追求通量 → 低目數
? 追求清液清澈度 → 高目數

3?? 濾餅含水率要求
? 高壓脫水工況 → 建議中高目數配合合理織造結構

4?? 行業參考

行業 常見目數區間
銅/鎳精礦 150–300目
污泥脫水 100–200目
化工精細過濾 300–500目

（具體仍需根據物料粒徑分布測試確定）

四、常見板框過濾布型號

常見型號包括：
? 丙綸750系列（750A / 750B / 750AB）
? 丙綸108C
? 丙綸840AB
? 滌綸621
? 滌綸3927
? 錦綸6533

不同材質區別：

材質 特點
丙綸 耐酸堿、性價比高
滌綸 強度高、耐磨
錦綸 彈性好、耐沖擊

五、丙綸濾布優勢

蘇東壓濾機丙綸系列濾布已通過檢測認證，符合法規多項檢測標準。

特別適用于：
? 大過濾面積臥式壓濾機
? 多室結構設備
? 密封要求高的工況

可有效解決：
? 密封差
? 漏料
? 濾布變形

并具備：
? 供貨穩定
? 專業硫化技術團隊支持
? 高性價比

六、選型核心建議

目數 ≠ 唯一標準

板框過濾布選型應綜合：
? 目數（微米）
? 織造結構
? 單絲/復絲結構
? 克重
? 厚度
? 透氣量
? 設備壓力

真正實現：

濾布與設備的完美匹配

蘇東壓濾機濾布

? 1. 先明確尾渣的基本參數

建議先做污泥化驗（最好是實驗室過濾測試）：

參數 意義

固體含量（%） 決定濾布選擇及預處理需求

顆粒粒徑分布

影響過濾通量

泥漿黏度

影響泵送與脫水效果

濾餅干燥性

關乎出渣含水率

是否含纖維長鏈

長纖維可能纏繞濾布

若暫時無法化驗，可用歷史運行數據或在線濁度、固含量估算。

? 2. 根據產量確定規格與處理能力

造紙行業尾渣量大且用量不穩定，通常按日處理量或小時平均計算：

? 日處理量（噸/天）

? 設計流量（m3/h 或 t/h）

? 峰值負荷余量（建議 10–30%）

確定參數后選擇壓濾機規格：

日處理量 推薦壓濾機規格

<10 t/d 400–800 型

10–30 t/d 800–1200 型

>30 t/d 1200–1500 或更大

型號一般按板寬（mm）+板數設計，如 800×800 / 1000×1000 / 1200×1200 / 1500×1500。

? 3. 選壓濾機板框類型

造紙尾渣壓濾機常用以下結構：

? (1) 板框式壓濾機

? 優點：結構簡單、設備投資低

? 缺點：占地大、自動化程度低

? 適合：產量小、資金受限

? (2) 壓縮式（楔形 / 壓榨式）壓濾機

? 有機械壓榨輔助壓濾

? 脫水效果好、濾餅更干

? (3) 自動快開式壓濾機（頂裝 / 邊裝）

? 自動開閉、濾布自動清洗

? 適合高頻開閉的場景

對于造紙尾渣常選 自動快開 + 壓縮型壓濾機，出渣含水率較低，易于運輸與后續處理。

? 4. 濾布選擇（對脫水效果關鍵）

尾渣富含長纖維、易堵布，因此：

?? 材質推薦：

? PET / PPS / PA（耐磨、耐高溫、耐堿）

? 單層或雙層復合濾布

? 較粗濾孔，有利于纖維通過（減少堵布）

?? 結構形式：

? 方格紋 / 網狀紋理 → 抗堵性能好

? 過濾速度快、易清洗

?? 濾布清洗方式：

? 高頻反沖洗

? 高壓水槍自動清洗

? 濾布更換便捷

? 5. 預處理設計

為了提高壓濾效果，一般需要配合預處理：

? (1) 化學絮凝

? 投加聚丙烯酰胺（PAM）

? 投加無機絮凝劑（如 PAC、硫酸鋁）

目的：

? 粒子聚團 → 形成易濾性絮凝體

? 降低濾餅含水率

? 提高過濾通量

需要實驗室或現場試劑調試最佳投加量。

? 6. 驅動與自動化控制

建議配置：

? 變頻驅動推進

? 自動開閉控制系統

? 壓力 / 液位 / 流量監控

自動化可顯著提升：

? 運行穩定性

? 操作安全性

? 人力成本減少

? 7. 后端排渣與運輸

根據脫水后的濾餅用途或處理方式：

? 低含水率 → 可燃燒 / 堆肥 / 回用

? 中含水率 → 堆放、再干燥

? 高含水率 → 需進一步干燥

需預留：

?? 皮帶輸送機或刮板輸送

?? 濾餅集料箱

?? 污泥泵與泵房

? 8. 現場條件約束

在選型時還要考慮：

? 建筑高度 / 吊裝空間

? 電力供應

? 污泥泵揚程與管路

? 排水條件

?? 實例選型（參考）

序號 日處理量 污泥特點 推薦機型

1 15 t/d 中等固含量尾渣 1000×1000 自動壓榨式

2 40 t/d 高纖維、高黏度 1200×1200 全自動壓濾機

3 5 t/d 低量試運行 800×800 板框式

?? 選型流程建議

1. 化驗尾渣（固含量、濾速、黏度）

2. 做小試或現場試驗（絮凝劑篩選 + 壓濾測試）

3. 估算處理量 + 設計冗余

4. 確定主機型號 + 驅動 + 控制

5. 配置絮凝系統 + 輸送系統 + 自動化

如果你愿意提供 尾渣具體化驗數據 / 日處理量 / 現場照片或流程圖，我可以幫你做進一步的 精確機型配置與報價建議。

報價咨詢：18851718517

在壓濾機設備中，filter plate是決定過濾效果和設備穩定性的核心部件之一。濾板質量的高低，直接影響過濾效率、濾餅含水率以及設備的使用壽命。蘇東壓濾機濾板作為壓濾機關鍵配套產品，憑借合理的結構設計、穩定的性能表現和良好的適應性，被廣泛應用于多個行業的固液分離工況中。

一、蘇東壓濾機濾板的結構特點

蘇東壓濾機濾板在設計上充分考慮了過濾效率與密封性能的平衡。濾板表面溝槽分布均勻，有利于濾液快速排出，減少過濾阻力，提高整體過濾速度。邊框密封面平整度高，在壓緊狀態下能夠有效防止跑料、漏料現象的發生。

濾板整體結構強度高，受壓均勻，在長期高壓過濾環境下不易變形，為壓濾機穩定運行提供可靠保障。

二、濾板材質與性能優勢

蘇東壓濾機濾板通常采用高強度聚丙烯等材料制成，具有良好的耐壓性、耐腐蝕性和耐磨性，適用于多種復雜工況。針對化工、環保等對耐腐蝕要求較高的行業，濾板在材料配比和成型工藝上進行了優化，能夠有效延長使用壽命。

同時，濾板表面光滑，濾餅易于脫落，有助于提高卸料效率，減少人工清理時間。

三、濾板規格齊全，支持定制

為滿足不同行業和不同處理量的需求，蘇東壓濾機濾板規格齊全，可匹配多種型號壓濾機使用。過濾面積、板框尺寸、進料方式均可根據客戶實際工況進行合理配置。

對于特殊物料或特殊工藝要求，蘇東壓濾機濾板還可提供定制化方案，在濾板厚度、進料孔位置及密封結構等方面進行針對性設計，更好地滿足現場使用需求。

四、廣泛的應用領域

蘇東壓濾機濾板已廣泛應用于污水處理、污泥脫水、化工過濾、礦山選礦、食品加工等多個領域。在環保行業中，濾板能夠有效降低污泥含水率；在化工行業中，可滿足對耐腐蝕和密封性能的高要求；在礦山行業中，濾板結構堅固，適合高壓、大處理量工況。

五、質量控制與使用保障

蘇東壓濾機濾板在生產過程中實行嚴格的質量控制，從原材料選擇、模壓成型到成品檢測，每一道工序均經過嚴格把關。出廠前對濾板進行耐壓、密封和外觀檢測，確保產品性能穩定可靠。

同時，廠家可為客戶提供濾板選型建議和使用指導，幫助客戶延長濾板使用周期，降低維護成本。

六、持續優化與技術提升

隨著壓濾技術的發展，蘇東壓濾機濾板在結構設計和材料工藝方面不斷優化升級，在保證強度的同時，進一步提升過濾效率和耐用性，為企業生產提供更高效的支持。

concluding remarks

總體來看，蘇東壓濾機濾板憑借穩定的質量、合理的結構設計和良好的應用表現，已成為壓濾機配件中的重要選擇。無論是新設備配套，還是舊設備更換濾板，蘇東壓濾機濾板都能為用戶提供可靠的過濾保障。

在工業生產中，高效過濾是提升產能、降低成本的關鍵環節。蘇東壓濾機憑借先進工藝與匠心品質，為各行業提供穩定、耐用、智能化的過濾解決方案，助力企業實現綠色高效生產！

為什么選擇蘇東壓濾機？

??卓越性能——采用高強度聚丙烯濾板，耐腐蝕、抗變形，過濾效率提升40%，確保長期穩定運行。
??節能降耗——優化液壓系統，能耗降低35%，運行成本更低，符合現代企業節能需求。
??智能控制——配備全自動PLC控制系統，支持遠程監控、故障報警，操作更便捷，減少人工干預。
??廣泛適用——適用于礦山尾礦、化工污泥、食品發酵、環保污水處理等領域，滿足不同工況需求。
??定制服務——根據客戶實際需求，提供濾板材質、過濾面積、自動化程度等個性化配置，精準匹配生產要求。

蘇東壓濾機，助您輕松應對嚴苛過濾挑戰！

無論是高粘度物料，還是高精度過濾，蘇東壓濾機都能以更低的能耗、更高的效率完成任務，讓生產更順暢，成本更可控！

立即聯系蘇東壓濾機廠家，獲取專屬技術方案！

核心關鍵詞：蘇東壓濾機、高效壓濾機、固液分離設備、工業過濾機、智能壓濾機廠家、污泥脫水設備、化工壓濾機

隨著環保政策持續加碼，越來越多的企業開始關注過濾設備的品質與效率。在眾多壓濾機品牌中，蘇東壓濾機以穩定性能、合理價格和定制能力脫穎而出，成為各行業用戶優選的固液分離設備之一。

蘇東壓濾機產品涵蓋板框式、隔膜式、全自動、手動壓濾機等多個系列，廣泛應用于污水處理、制藥、食品、選礦、化工、冶金等領域。無論您是初創企業，還是大型工程項目，蘇東都能根據實際工況提供合適的過濾解決方案。

為什么選擇蘇東壓濾機？

1. 源頭直供，品質可控：所有壓濾機均由本地實力廠家生產，嚴控每一道工藝，保障設備質量。

2. 技術成熟，維護方便：采用加厚濾板、智能液壓系統，降低故障率，便于日常保養。

3. 支持定制，按需選型：提供非標壓濾機定制服務，適配特殊場景或復雜工藝要求。

4. 售后無憂，服務到位：蘇東配有專業技術團隊，提供現場安裝、調試、培訓等一體化服務。

越來越多用戶在百度搜索“蘇東壓濾機”時，不只是為了了解產品，更是為了找到一個可靠的合作伙伴。選擇蘇東，就是選擇一個重視品質、服務和效率的品牌。

Lithium has a low melting point, high boiling point, most negative potential, light mass, etc.,It is widely used in new energy vehicles, nuclear industry, aviation, medical, and other fields. Lithium is the most important basic raw material for new energy industry.,be known as "21New Energy for the Century". In order to accelerate the realisation of the strategic goal of "Carbon Neutral, Carbon Peak".,China has vigorously developed the lithium new energy industry,Demand for lithium feedstock is increasing year on year,Lithium's growing strategic position,A new round of competition for mineral resources has been launched[. Currently,The main sources of domestic lithium resources are salt lake lithium and ore lithium. Ore lithium mainly includes lithium pyroxene, lithium mica, lithium feldspar, lithium iron mica, lithium muscovite, lithium aluminium phosphorite, etc.. To ensure stable market supply of lithium raw materials,Lithium extraction from lithium mica,Has become an important way to obtain lithium feedstock,Yichun area in Jiangxi has the world's largest associated lithium mica mine[12]. During the beneficiation of lithium mica,Belt filters are commonly used in the dewatering of lithium mica concentrates.,Concentrate moisture is generally greater than18%,There are features such as high moisture of lithium mica concentrate, large equipment footprint and low processing efficiency. A mineral processing plant in Yichun area adopts a company's production ofFFPDewatering of lithium mica concentrate by horizontal quick opening filter presses,It has the characteristics of small equipment footprint, high processing efficiency and low moisture of lithium mica concentrate.,at the same time,It can reduce the transport cost of lithium mica concentrate and the drying cost of downstream lithium carbonate plant. This paper focuses onEffect of filter cloth type, cycle time, working pressure, type of filter aid, and dosage of filter aid in lithium mica concentrate on the moisture of lithium mica concentrate in a fast-opening filter press.

1The test specimens were taken from a lithium mica concentrate of a mineral processing plant in Yichun area.,The results of multi-element chemical analyses of this lithium mica concentrate and the results of sieve analyses of the lithium mica concentrate are shown in Table1wristwatches2The From the table1wristwatches2knowable,This lithium mica concentrateLi2Oquantity contained1.71%,Al2O3quantity contained29.34%,SiO2quantity contained47.60%. Lithium mica concentrate particle size<75μmContent as a percentage of32.79%,<25μmContent as a percentage of14.63%,The dewatering process is difficult and the concentrate moisture is high when using traditional belt filter dewatering.2FFPHorizontal quick-opening filter press introductionQuick-open horizontalFilter press is a high capacity filter press.,Mainly used for solid-liquid separation.FFPQuick-opening horizontal filter press is shown in the figure.1Shown. Operating time,The main steps are as follows.

1)infeed:The material is pumped to each filter chamber of the filter press.,Until it's completely full.

2)filtration:Rising feed pressure,Cake formation on the surface of the filter cloth,The filtrate is discharged through a collection channel.

3)squeezes:Diaphragm after extruded media enters each chamber,The diaphragm squeezes the cake between the filter cloths.,Force the filtrate through the filter cloth.

4)air dryness:Compressed air passes through the filtrate channel on the diaphragm side,Blow-dry the moisture in the filter cake to a minimum. During the drying process,The filter cake keeps the diaphragm squeezed,The filter cake can be maintained without cracking.

5)Pipe flushing, blowing:Residual slurry and water in the pipeline is cleaned and disposed of.

6)Diaphragm Release:The compressed air in the diaphragm is completely released.

7)pancake unloading:approximate30sshort time,All the filter cake is discharged at once. When the filter plate set is fully opened,The filter cloth is vibrated to ensure complete cake discharge.

8)Filter cloth rinsing:After unloading the cake,The filter cloth is flushed by a shower pipe mounted on top of the filter plate set. This ensures the removal of residual filter cake from the surface of the filter cloth.,and ensure good running conditions for the next cycle.Quick-open horizontalFilter presses have the following advantages:

1)High efficiency of equipment operation,Short technical time for opening and closing plates, etc.(<30s).

2)Weighing system installed,Measurement of the feed volume at any time,and automatically adjusts operating parameters;

3)Filter plates in accordance with European quality standards,Reliable quality, removable and replaceable edge wear parts,No need to replace the entire filter plate;

4)Automatic vibration of the filter cloth after discharging the cake,Helps to unload the cake and remove residual cake crumbs,Completely eliminates the need for manually assisted unloading,Avoid residue being trapped between the filter plates,Causes deformation of slurry or filter plates;

5)High degree of automation,the scene (of the incident)PLCcompatibility withDCSsystem connection,Observation of equipment operation status and remote start/stop can be realised in the central control room.;

6)Low running costs,Fully automatic operation of the whole plant,The site is largely unmanned,It can save more labour cost for customers.

3Results and Discussion A lithium mica concentrate from a beneficiation plant in the Yichun area was used as the object of study.,Lithium mica concentrate particle size<75μmquantity contained32.79%,Slurry concentration55%. Slurry concentration determines filter press feed time,When the slurry concentration is constant,The feed time is unchanged.

3.1Filter Press Cloth Type Condition Test Filter cloth is quite a key component in the filter press equipment.,Because of the different substances filtered by the industry,Relatively different requirements for filter cloth,This results in many types of filter cloths. In this paper, a suitable filter cloth for dewatering lithium mica concentrates is identified through industrial tests in the field.,existFFPHorizontal quick release filter press cycle time900s (Of which feed time180s.squeeze time330s.drying time360s)Work stress1MPaconstant time,To investigate the effect of different filter cloth types on the moisture of lithium mica concentrate. The test results are shown in Table3drawing2. From the table3drawing2knowable,Air permeability using nylon monofilaments300L/(m2)-min)of filter cloth lithium mica concentrate with the lowest moisture content,because of15.89%,And it was found in the test that nylon monofilament filter cloth has better peeling performance,Rapid cake stripping,The main reason for this is the high filtration accuracy and precision of nylon monofilament filter cloths.,It can filter out data with a diameter of1μmmicroparticles,This will help to prolong the use cycle of the filter cloth and improve the efficiency of the filter press.

3.2Filter press cycle time condition test Horizontal quick-opening filter press with nylon monofilament air permeability300L/(m2)-min)Filter cloth, working pressure1MPaconstant time,The effect of filter press cycle time on the moisture of lithium mica concentrate was investigated. The test results are shown in Table4drawing3. From the table4drawing3knowable,As the slurry concentration is more consistent,Then the feed and filtration times are the same,With the increase of extrusion time, drying time,Lithium mica concentrate moisture is reduced. When the total cycle time exceeds930ssurname Shi,Lithium mica concentrate moisture reduction is not significant. Taken together,Select cycle time930sOperating parameters as a filter press,At this time, the moisture of lithium mica concentrate is15.32%.

3.3Test of working pressure conditions of quick-opening filter pressesFFPHorizontal quick-open filter press with nylon monofilament air permeability300L/(m2)-min)Filter cloth, cycle time930s (where extrusion time345s.drying time375s)constant time,To investigate the effect of filter press working pressure on the moisture of lithium mica concentrate. The test results are shown in Table5drawing4. From the table5drawing4knowable,With the increased pressure of work,Lithium mica concentrate moisture reduction. When the working pressure of the filter press exceeds1.1MPasurname Shi,Slow reduction in concentrate moisture,a round-up,Determining work pressure1.1MPaOperating parameters as a filter press,At this time, the moisture of lithium mica concentrate is15%.

3.4Lithium mica concentrate filter aid type condition testcetestntrateFFPHorizontal quick-opening filter press filter cloth type, cycle time, working pressure and other equipment parameters to determine the,To investigate the effect of filter aid type and filter aid dosage on the moisture of lithium mica concentrate. The effect of filter aid type on the moisture of lithium mica concentrate was investigated first. The inorganic filter aid polymeric aluminium chloride, organic filter aid840Organic filter aids320Filter aid comparison tests were conducted. At the same dosage500g/tpresent situation,To investigate the effect of filter aid type on the moisture of lithium mica concentrate. The test results are shown in Fig.5. By Chart5knowable,At the same dosage500g/tpresent situation,When making polymerised aluminium chloride,Lithium mica concentrate moisture13expense or outlay.79%Filtering effect of polymerised aluminium chloride. Filtering aid effect polymerised aluminium chloride>organic filter aid320>organic filter aid840,This is due to the fact that the molecular chains of polymeric aluminium chloride are fixed on the surface of different fine or very fine particles.,Aggregates formed by the formation of polymer bridges between individual fine or very fine particles,Aggregates do not cause clogging of the filter pores of the filter cloth during filtration.,At the same time the stripping of the filter cake is better,The filter cloth has a longer life cycle.

3.5Lithium mica concentrate filter aid dosage condition testFFPAir permeability of nylon monofilaments used in horizontal quick-opening filter presses300L/(m2)-min)Filter cloth, cycle time930sWork stress1.1MPaPolymeric aluminium chloride for filter aids,To investigate the effect of polymeric aluminium chloride dosage on the moisture of lithium mica concentrate. The test results are shown in Table6drawing6The From the table6drawing6knowable,With the increased use of polymeric aluminium chloride,Reduced moisture in lithium mica concentrate. At polymeric aluminium chloride dosages greater than450g/tsurname Shi,Smaller rate of moisture reduction in lithium mica concentrate,Consideration of costs, etc.,Selection of polymeric aluminium chloride dosage450g/t,At this time lithium mica concentrate moisture13.80%.3.6FFPComparative analysis of horizontal quick opening filter press and traditional belt filter according to lithium mica concentrate743.75t/h (dry tonne)Selection Calculation,FFPComparative analysis of horizontal quick-opening filter press and traditional belt filter is shown in the table.7. From the table7knowable,FFPHorizontal quick-opening filter press has the features of small equipment footprint, high dewatering efficiency, high degree of automation and saving transport costs.

4reach a verdict

1)A lithium mica concentrate from a beneficiation plant in Yichun area as a research object,This is achieved through a review of theFFPStudy on the type of filter cloth, cycle time, working pressure, type of filter aid and dosage of filter aid for lithium mica concentrate in horizontal quick-opening filter presses,The results of the tests show thatFFPAir permeability of nylon monofilaments used in horizontal quick-opening filter presses300L/(m2)-min)Filter cloth, cycle time930sWork stress1.1MPaPolymeric aluminium chloride for filter aids450g/tsurname Shi,The lithium mica concentrate has a moisture of13.80%.

2)Lithium mica concentrate in filter aid condition test,Polymeric aluminium chloride is the most effective in reducing the water content of lithium mica concentrates,Filtering effect polymeric aluminium chloride>organic filter aid320>organic filter aid840This is due to the fact that the molecular chains of polymeric aluminium chloride are fixed on the surface of different fine or very fine particles. This is due to the fact that the molecular chains of polymeric aluminium chloride are fixed on the surface of different fine or very fine particles.,Aggregates formed by the formation of polymer bridges between individual fine or very fine particles,Aggregates do not cause clogging of the filter pores of the filter cloth during filtration.,At the same time the stripping of the filter cake is better,The filter cloth has a longer life cycle.3)Compared to belt filters,A mineral processing plant in the Yichun area usesFFPHorizontal fast-opening filter press has the characteristics of small equipment footprint, high dewatering efficiency, high degree of automation, saving transport costs and so on.,Solved the industry problem of high moisture in lithium mica concentrate in Yichun area.,It is the first time to be successfully applied in large scale in the lithium mica beneficiation industry.,Very important demonstration significance in the industry,Future applications are promising.

Author: Guo greatness,Chen Yifeng (1901-1981), Mao Zedong's first wife,Xie 添,Tang Lijing (1897-1987), translator and editor of the Ming dynasty

In the coal gasification industry, the gasification filter cake is usually blended into the power coal for blending and use, but because of the high water content of the filter cake, direct blending will cause power coal plugging. In order to reduce the risk of power coal blending and plugging, it is necessary to further reduce the water content of the filter cake. Plate and frame filter press can well reduce the water content of the cake, so to ensure the stable operation of the plate and frame filter press. Based on this to discuss the common problems in the operation of the plate and frame filter press and treatment measures.1 Common Solid-Liquid Separation Equipment Introduction to 4 common types of solid-liquid separation equipment.

1 Vacuum Belt Filter Through the coordinated operation of the rotary motor, reducer and haul-off rollers, the Vacuum Belt Filter can effectively utilise the pressure change of the material and the maximum vacuum it brings to achieve solid-liquid separation. In addition, the filter cloth is mounted on the belt to better fulfil the entire filtration process. The connection of an annular friction belt and a water seal allows the tracks to slide effectively between the vacuum bins. At the same time, by connecting the vacuum equipment, a vacuum filtration zone can be constructed on the surface of the track, and a large amount of slurry can be smoothly transferred to the filter cloth.

1.2 Disc Vacuum FilterThe disc vacuum filter has excellent filtration performance, which can effectively separate the slurry from other materials and achieve more efficient filtration by changing the vacuum flow rate. In addition, disc vacuum filter also has a series of latest technology, such as adjustable agitator, adjustable exhaust device, adjustable filter disc guide frame.

1.3 Screw discharge sedimentation centrifugeScrew discharge sedimentation centrifuge is a centrifugal sedimentation to achieve the purpose of completely separated from the natural fluid, mainly used for solid-phase dewatering. Theoretically, the spiral discharge sedimentation centrifuge utilises the principle of density difference between the solid and liquid phases, and the liquid phase produced is clearer and the water content of the solid phase is less.

1.4 Plate and frame filter presses are made of many filter plates with striped patterns and filter frames that are assembled into a machine after regular display. Plate and frame filter presses are usually operated intermittently and have a relatively low capacity. However, plate and frame filter presses usually have a strong filtration drive and produce a dry filter cake that can beRecycling.

2 Plate and frame filter press operation process

2.1 Plate and frame filter press systems Plate and frame filter press systems include slurry tanks, feed pumps, filter press thrust plates, filter plates, main beam machines, press tanks, press pumps, cloth washing tanks, cloth washing pumps, belt conveyors, compressed air tanks, instrument air tanks.?hold down plate saddle cylinder electronic control cabinet Hydraulic station diagram5 PLATE AND FRAME FILTER PRESS CONSTITUTIONAL PARTS The plate and frame filter press consists of a plurality of parts, including a thrust plate, a main beam, a pressurised plate, a manual pulling plate system, a machine base, an electric control cabinet, a hydraulic control system, a water-washing filter cloth apparatus, a flap apparatus, a filter cloth, a discharge port, a diaphragm press and a filtrate discharge device, as well as a population and an outlet for slurry, and equipment for connecting the filter cloth and water. By means of an efficient slurry conveying system, a closed space is created between the two filter plates of the filter press in order to generate a high pressure and effectively isolate the filtrate and cake.

2.2 Plate and frame filter press operation process

(1) Feeding: when the slurry is added to the storage tank, the plate and frame filter press pushes the slurry through the pressure to flow into the filter chamber composed of multiple filter plates, and eventually fills the whole chamber to form a thick layer of filter cake.

(2) Filter Cake: As the material flows, this layer of filter cake is extruded and eventually sent by the belt conveyor to the vehicle that pulls the filter cake, which is collected and used for power coal blending.

(3) Filtrate: After the slurry is dewatered by the filter press, the clear liquid is discharged from the filter press and flows to the grinding pool.

(4) Filter plate group: a group of adjacent and positioned filter plates, installed between the press plate and thrust plate of the filter press.

(5) Diaphragm pressing: water is pressed and delivered to the diaphragm plate, causing the diaphragm chamber to expand, further discharging the filtrate remaining in the cake by shortening the volume of the filter chamber.

(6) Flap device: In order to make the filtrate, filter cloth rinsing water does not flow into the filter cake, conveying track, receiving car, the flap device through the hydraulic cylinder expansion and contraction action, in the filter cake discharged before the opening of the flap, the filter cake discharged after the closure of the flap ?.

3 Plate and frame filter press operation common faults and treatment

3.1 insufficient oil pressure oil pressure is insufficient to generate the causes of oil pressure pump (see Figure 6) relief valve failure, oil pump failure, valve block and joint leakage, oil red seal aging, valve seepage or oil level is too low. Treatment measures for the faulty parts of the repair or replacement.

3.2 Pressing pressure is low pressing pressure is low mainly for the press pump pressure is not enough, can not carry out the next procedure. Causes are mostly cracked filter press water pipe, press tank level empty, press pump failure, instrumentation valve failure can not be opened and so on. Treatment measures are generally replaced, repaired or contact the instrumentation staff to deal with the valve.

3.3 between the filter plate leakage filter plate leakage is usually caused by the feed pump pressure and flow is too large, resulting in filter plate, diaphragm sealing surface m now dirt, filter cloth is not smooth with folds, and oil pressure instability. Treatment measures for readjustment of the feed pump and clean up the filter cloth, adjust the oil pressure to the same as appropriate.

3.4 Filter plate breakage Filter plate breakage is caused by damage to the filter cloth, resulting in incomplete filling of the filter with cake, excessively high loading rates, obstruction of the inlet pipework to the filter plate and diaphragm, and obstruction of the air vent valve. Measures taken include: replacing the filter cloth in a timely manner to ensure that the filter cake fills the chamber for pressing; slowing down the feed rate; cleaning the holes in the feed hopper; and keeping the inside of the filter plate clean.

3.5 Upward lifting of the filter plate The reason for upward lifting of the filter plate is that the installation foundation is not stable or the lower part of the filter plate is not clean of slag. The treatment measures are to re-grade the foundation and remove the slag under the filter plate.

3.6 The filtrate is not clear and the plate and frame feed time is long the filtrate is not clear and the plate and frame feed time is long the production of the original Gang may be a broken filter cloth, screen size deviation, screen joints have cracks, pipeline leaks, and the feed pump operation problems (such as impeller fall off or the feed pump outlet valve is not open). The treatment measures are to check and replace the filter cloth and eliminate the defects or leaks in the equipment and pipelines.

3.7 hydraulic system noise hydraulic system noise may be the cause of suction air, loose fasteners, hydraulic oil viscosity is too large, return filter clogging. Treatment measures to open the exhaust valve to ensure that the fasteners are firm, reduce the viscosity of the hydraulic oil.

3.9 Filter press inoperative Filter press inoperative is caused by the limit of the filter press itself, as well as the failure of the press pressure gauge to reach the set minimum value. Treatment measures is to contact the transport and maintenance personnel to make adjustments in a timely manner.

3.10 Clogging of the filter cloth Over time, the filter cloth of the filter press may become clogged. When the filtration time is significantly shortened, the water in the cake is significantly reduced, the instantaneous filtration pressure of the filter press is significantly increased, which leads to a significant acceleration of the liquid time, then the filter cloth must be cleaned. Usually the original filter cloth is removed and then re-cleaned, but this practice is time-consuming and labour-intensive. South of the traditional cleaning method there are large defects, such as cleaning pressure is small, the requirement of cleaning the surface smooth, etc., the cleaning efficiency is low. For this reason, this system adopts automatic filter cloth rinsing device, installed in the upper part of the filter press rinsing mechanism, the use of high-pressure water shunts to a number of nozzles, through the rinsing device of the programme control system, lifting device, and the automatic pulling plate system of the filter press, and jointly on the installation of the filter cloth on the filter plate rinsing one by one.

3.11 Other fault judgement

(1) The feed pump feeds for a long time, the feed pressure is not enough, and the discharged filtrate is seriously entrained with black water. Possible causes are broken filter cloth and leakage in pipeline. At this time, the pipeline, filter cloth should be immediately checked and eliminated.

(2) The feed pump can be operated, but the level of the slurry tank drops slowly, and the feed pressure is not under pressure. Possible reasons for the feed pump impeller off or the valve outlet is not open. Treatment measures for timely inspection of the feed pump operation.

(3) pressure on the process does not go to the pressure, may be due to oil leakage at the pipeline, the pump station hydraulic oil level is too low, oil pump failure, check valve damage, cylinder sealing damage, and so on.

(4) The pipeline and cylinder seal is not good, the check valve and solenoid ball valve is damaged, there may be pressure after the pressure does not hold pressure.

(5) Pressure gauge damage or loose wiring in the process of compression, may appear to reach the upper limit of pressure but the compression process does not stop.

(6) If the plate and frame filter press is not configured with the number of plates according to the nameplate of the filter press during operation, the oil pump may stop without reaching the upper pressure limit during operation.

(7) The pull plate trolley and chain are stuck by foreign objects, which will cause the pull plate trolley abnormal. In daily work, oil the chain and runway regularly to ensure that the lubrication parts are good.

4 Conclusion In summary, mechanical leakage, procedural errors and other problems are more likely to occur during the operation of the plate and frame filter press, and the optimisation of treatment measures for the above problems will help to solve the problems and ensure the stable operation of the system. In the future, it is also necessary to optimise the process of the plate and frame filter press itself and improve the technical level of the operators to ensure the long life cycle of the plate and frame filter press system.

Author: Ma Xiaogang Zhang Ying Ma Xiaogang, Zhang Ying

2 Working Principle of Filter Press When filtration starts, the coal slurry water enters into each filter chamber through the feeding ports in the middle of the thrust plates on both sides under the push of the feeding pump, and the coal slurry water is separated from the solid-liquid by the pressure of the feeding pump. Due to the action of filtering medium, the solids larger than the gap of the filter cloth remain in the filter chamber to form filter cake; the filtrate and a small part of very fine coal sludge smaller than the gap of the filter cloth are discharged by the discharge valve and recycled. In use, if it is necessary to filter the cake with lower moisture, high pressure compressed air can be fed into the air inlet at the upper right corner of the upper push plate to press the cake to further reduce its moisture; or high pressure air can be fed into the air inlet at the centre of the press plate to pass through the cake layer and carry out the intermediate air flow to further squeeze out the excess water in the cake.

3 Analysis of problems in field application In the field application of quick-opening diaphragm filter press, it is found that when the equipment is shut down in emergency or the belt conveyor for transporting fine coal is shut down, it is necessary to discharge the quick-opening diaphragm filter press in time. However, due to the problem of high liquid level in the feeding cylinder of the fast-opening diaphragm filter press, it is difficult to discharge the filter, which is very easy to cause the main shaft of the filter to block. If the material is forced to be discharged, there will be overflow of the barrel. When the quick-opening diaphragm filter press cannot be used normally, the coal sludge in the thickening pool cannot be discharged in time, which affects the normal production of the coal washing plant.

4 System Optimisation Study Filter in normal use found that the level of the upper material cylinder is often in the 50% above, if the normal discharge is not very easy to program you to block the rotationProblems. Therefore, the optimisation of the filter system is considered in the paper in terms of the discharge process of the filter and the spindle speed.

4.1 Optimisation of spindle speed In general, the spindle speed of the filter is reasonably set in the range of 0.87~1.5r/min, and the rotational speed of the filter is set at 1.01r/min when dewatering fine coal slurry in the field. The lower the rotational speed of main shaft, the lower the number of slurry boards, the lower the product moisture and the more likely to be blocked; the higher the rotational speed, the higher the product moisture, and the product moisture will not meet the requirements after the rotational speed exceeds a certain value. Through the above analyses and combining with the previous research results, it is decided to increase the main shaft speed of the filter from 1.01r/min to 1.30r/min, so as to ensure that the filter can operate efficiently.

4.2 Optimisation of discharging process When the liquid level in the upper material cylinder is lower than 20%, the bottom flow pump will automatically feed, when the liquid level is higher than 80%, the bottom flow pump will stop working. If there is an urgent need to stop coal slurry or coal in the process of pressurisation and filtration, the bottom flow pump will still work automatically according to the liquid level of the upper barrel, generally the liquid level in the upper barrel is 60~80%, at this time, the material of the slurry tank will flow into the upper barrel, and when the inflow exceeds 40% of the liquid level, the upper barrel will be overflowing. If the material in the slurry tank can not be emptied quickly, the filter is very prone to blocking in the subsequent operation, if the material in the slurry tank can be emptied, there will be no blocking. The problem of emptying the slurry tank can be solved by reforming the slurry tank discharge method of the quick-opening diaphragm filter press. At this stage, the following two methods can be used to discharge the slurry tank of the quick-opening diaphragm filter press: Lower the liquid level in the upper barrel to ensure that the upper barrel has enough space to store materials. However, if the liquid level in the slurry loading cylinder is lowered too much, there is the problem of frequent startup of the bottom flow pump, which is not conducive to the efficient development of coal washing; if the liquid level is lowered too little, the storage space cannot be increased effectively, and the material in the loading cylinder will still have overflow problems. By improving the discharge system, the slurry tank materials can be discharged to other locations for temporary storage. The specific improvement is to optimise the discharge piping arrangement, so that the material in the slurry tank can be discharged to the protection box, and then returned to the thickening tank; the material in the thickening tank can be pumped to the upper barrel by using a bottom-flow pump, so as to achieve the cycle of material loading. After the above improvement, the discharge of materials in the slurry tank will not affect the liquid level in the upper barrel, thus effectively solving the problem of overflowing barrel in the upper barrel.

5 Analysis of the effect of modification Optimisation of the main shaft speed and discharge process of the fast-opening diaphragm filter press at the Hupoji Coal Washing Plant. After optimisation, the moisture content of the product produced by the filter is within a reasonable range, and at the same time, the path of material discharge in the slurry tank is shifted from the original loading cylinder to the thickening pool, thus effectively avoiding the overflow problem of the loading cylinder. The material discharge pipework was flanged during the on-site modification and optimisation, so that it can be dismantled and replaced in the event of serious wear and clogging. After the field application, the working condition of the quick-opening diaphragm filter press after the completion of the modification was investigated. It was found that when there is an emergency stoppage of coal slurry or coal in the coal washing plant, the materials in the slurry tank can be discharged into the protection box to achieve timely emptying of materials, and the problem of filter spindle plugging was increased from an average of once every three months before the renovation to once every nine months, and the incidence of filter spindle plugging has been reduced through the optimisation effectively. Through optimisation, the annual investment can be reduced by about 103,000 RMB, which not only reduces the labour intensity of operators but also shortens the time of equipment maintenance, and to a certain extent improves the economic benefits of the coal washing plant. At the same time, the upgrading reduces the product moisture, reduces the use of tap water, and saves a lot of social costs. The labour intensity of the operators has been reduced from four persons to only two persons. The pollution of the surrounding environment by coal slurry and the noise pollution of the flotation workshop have been greatly reduced, bringing significant social benefits.

6 Conclusion In this paper, the model ZKG450/2000-U fast-opening diaphragm filter press system used for fine coal slurry in the coal washing plant at the bottom of the slopes is optimised, specifically, the main shaft speed is optimised from 1.01r/min to 1.30r/min, and the product not only meets the requirement of water content but also improves the operating efficiency of the filter; the discharge process of the slurry tank is optimised, specifically the material in the slurry tank can be discharged into the protection box and then returned to the thickening pool, thus avoiding the material in the slurry tank from flowing into the feeding cylinder and leading to material overflow problems. The slurry tank discharge process is optimised, specifically, the material in the slurry tank can be discharged to the protection box, and then returned to the thickening pool, thus avoiding the material in the slurry tank to flow into the feeding cylinder, resulting in material spillage, and reducing the incidence of filter spindle jamming. After the application on site, the interval of filter blockage rate has increased from 3 months to 9 months, and it is estimated that the annual cost can be saved about 103,000 yuan, which effectively reduces the number of filter shaft blockage times and improves the comprehensive operating rate of coal washing equipment. After the fast-opening diaphragm filter press was formally put into use in Hu Po Di Coal Wash Plant, it saved a lot of operating costs for the plant due to its advantages of fast filtration and unloading speed, low moisture of the filter cake, large processing capacity, and high degree of automation; meanwhile, the machine has strong adaptability to the granularity composition of the incoming material, and it has a broad development prospect in processing viscous materials with fine granularity and high concentration.

Author:Zhao Zhenzhen

1. Establishment of compartmentsdiaphragm filter pressThe physical model of a single filter chamber, in the CFD simulation software Fluent using the standard seven-one-occupancy model, mixing model, porous media model, etc. to establish the mathematical model of the sludge solid-liquid two-phase flow field within a single filter chamber, to provide conditions for the simulation of solid-liquid two-phase flow simulation, the application of the model established above on the solid-liquid two-phase flow field within the chamber of the compartment-type diaphragm filter press single velocity distribution, pressure distribution, concentration distribution, etc. to carry out simulation. Simulation was carried out to obtain the change law of pressure drop at both ends of the cake, the formation law of the cake and the basic flow law of two-phase flow of sludge in the filter chamber;

3. Simulation analysis under different filtration pressures. Studied the velocity distribution in the filter chamber under different filtration pressures and the change rule of the water content of the filter cake;

4. Simulation analysis under different feeding methods. Comparing the sludge feeding method from the centre of the filter chamber with that from the upper part of the chamber to study the cake formation pattern and the uniformity of the formed cake, the results show that the sludge feeding method from the centre of the filter chamber is better than that from the upper part of the filter chamber;

5. Determination of optimal chamber thickness. The water content of the filter cake formed under different filter chamber thicknesses and the production rate of the filter cake per unit time were studied, and the optimum filter chamber thickness of 12mm was found in the comprehensive analysis of this research model;

6. Experiment on the filtration performance of the chamber diaphragm filter press and compare the experimental results with the simulation results, and find that the maximum error is within 10%, which verifies the correctness of the simulation results; through the termination of the feed and then carry out the press dewatering treatment, so that the water content of the cake is further reduced, and at the same time, this process has found a suitable starting point for the press. The results can be used to guide the design and use of chamber diaphragm filter presses.

Keywords: chamber diaphragm filter press; cake water content; numerical simulation; filtration pressure; filter chamber

Abstract: lm the large．scale construction of urban sewage treatment plant in our COUlltry,sludge generated has become a new source of environmental pollution, which have a high moisture content sludge and other issues, SO the depth of the sludge dewatering become one of these key research topics. 111e study found that when the agents modified of urban sludge finished, the sludge generated by the sludge dewatering process will be more efficient. study found that when the agents modified of urban sludge finished, sludge dewatering depth by Van membrane filter press sludge Can form cake with low In this paper,sludge filtration process and filter characteristics of filtration chamber in Van membrane filter press were studied by the method. In this paper,sludge filtration process and filter characteristics of filtration chamber in Van membrane filter press were studied by the method of the numerical simulation combined with experimental validation.The main work is as follows: Firstly The main work is as follows: Firstly, the paper establishes the physical model of single filtration chamber in Van membrane filter press.within fluent of the FLUENT simulation software. Firstly ,the paper establishes the physical model of single filtration chamber in Van membrane filter press. within fluent of the FLUENT simulation software, using the standard k-s model, hybrid model and porous media models, the mathematical model of the solid-liquid two． filtration chamber of Van membrane filter press has been built, which provided the conditions for the solid-liquid two-phase flow numerical simulation. Secondly, application of the above physical and mathematical models, speed distribution, pressure distribution, concentration field distribution, and the distribution of the two-phase flow field of Van membrane filter press have been built, which provided the conditions for the solid-liquid two-phase flow numerical simulation. in two-phase flow field of single filtration chamber in Van membrane filter press have simulated and got the changes law in pressure drop across the filter The two-phase flow field of single filtration chamber in Van membrane filter press have simulated and got the changes law in pressure drop across the filter cake, analysed the pattern of filter cake was formed and the basic flow law of sludge two-phase field in filtration chamber, etc.; Thirdly, simulation analysis under different filtration Thirdly, simulation analysis under different filtration pressures. studing the law of velocity distribution and the moisture content of cake formed under different filtration pressure. Thirdly, simulation analysis under different filtration pressures. studing the law of velocity distribution and the moisture content of cake formed under different filtration pressure; Fourthly, simulation analysis under different feeding methods. Comparison of sludge from the filter chamber centre feeding mode and the upper feeding mode, studying the formation of the cake and the uniformity of cake formed.The results show that the centre feed way is FifHl, determine the optimum thickness of filter chamber. studying the moisture content of cake formed and the cake volume yield per unit of time under different thickness of the filter chamber, comprehensive analysis to select 1 2ram as the best filter chamber thickness of the filter chamber. yield per unit of time under different thickness of the filter chamber,comprehensive analysis to select 1 2ram as the best filter chamber thickness of the research modle. research modle; Sixth, Filter performance test is taken on Van membrane filter press, experimental results obtained are compared with the simulation results, the maximum error iS less than 1 0%, to verify the correctness of the simulation; squeeze dewatering after feed finished, SO further reducing the moisture content of the cake, by experiment to find the right time as the press start point.T]. search results l research Can guide guide th,de: "g the desima and use of the vailIllS membrane fiiter press. this article has forty This article has forty-one pictures, seven tables, seventy-one references.

2 Working Principle of Diaphragm-type Plate and Frame Filter Press The sludge deep dewatering equipment adopted by the Guangzhou Paper Group is a fully automatic diaphragm-type plate and frame filter press. The automatic diaphragm filter press is a kind of intermittent pressurised filtration equipment, which can be used for solid-liquid separation of various suspensions. The principle of dewatering in this equipment is mainly through high pressure feeding and high pressure pressing. Under the effect of pressure, the water in the suspension in the filter chamber enters into the filtrate side through the filter cloth, while the solid particles are retained in the filter chamber under the interception of the filter cloth, thus realising the purpose of solid-liquid separation. Plate and frame filter presses are equipped with two types of filter plates: diaphragm plates and frame plates, which are arranged at intervals. The diaphragm plates are hollow and have a certain degree of expansion, while the frame plates are solid hard plates that act as a top press. When the press liquor is injected into the inner chamber of the diaphragm plate, the diaphragm plate gradually expands under the pressure, and the volume of the filter chamber becomes smaller and smaller, thus further squeezing out the sludge water in the filter chamber. The operation of the filter press is intermittent feeding, with one cycle consisting of feeding, pressing, draining and discharging. The moisture content of sludge treated by diaphragm-type plate and frame filter press can generally reach below 50%, and its dryness is related to the high pressure feed pressure and press pressure, but considering the economy of operation and safety of equipment, the design selects the high pressure feed pressure and press pressure to be 1.6MPa, and the dryness of sludge to be 50%~60%.

3 System design and operation and maintenance The wastewater treatment system of GZG is a tertiary treatment process, and the process flow is as follows: physical sedimentation, (Ic anaerobic + SBR aerobic) biochemical treatment, and shallow air flotation, so the sludge produced by the system is not only physical sludge produced by sedimentation, but also residual sludge produced by the biochemical treatment of the SBR and air flotation sludge. The process of the sludge treatment system is as follows: the physical sludge from the sedimentation tank and the residual biochemical sludge from the SBR enter the sludge thickening tank for thickening, and then sent to the filter press for treatment. The air-float sludge, which is combined with a large number of small bubbles and has a low specific gravity, is difficult to be thickened by gravity settling, so it goes directly to the sludge conditioning tank. The thickening tank is buffered and can be processed intermittently, but the air flotation sludge is produced continuously and sent to the sludge conditioning tank due to its continuous operation.The sludge concentration in the conditioning tank will fluctuate, and the flocculation effect of the chemicals will also fluctuate. Since the plate and frame filter press is fed intermittently, the sludge treatment capacity will change with the change of operation status, so the sludge concentration in the conditioning tank will fluctuate, and the flocculation effect of chemicals will also fluctuate, which will interfere with the normal operation of the filter press. In response to these problems, we focused on optimisation in the system design.

3.1 Increase the pre-dewatering facilities The previous design of plate and frame filter press dewatering system is that all kinds of sludge enter the sludge conditioning tank to be mixed and dosed with chemicals, and then fed into the plate and frame filter press by feed pumps for filter dewatering. The consistency of the feed depends on the mixing consistency of the various sludges entering the conditioning tank. The air-float sludge is difficult to thicken by the conventional gravity thickening method due to the low specific gravity of the air bubbles carried by the air-float sludge, so the system is generally designed to send the air-float sludge directly to the sludge mixing tank for dewatering. Due to the low concentration of the air-float sludge and the looseness of the sludge because of the fine air bubbles, the concentration of the mixed sludge will be low and the dewatering effect will be poor when the proportion of the air-float sludge is large, and it will easily be adsorbed on the surface of the filter cloth and block the filter channel of the filter cloth. In order to eliminate the influence of sludge concentration fluctuation on the operation, we designed a gravity bed for pre-dewatering before the sludge conditioning tank. The principle of gravity bed is: after flocculation, the suspended liquid enters the gravity bed, and under the effect of gravity, the external water of the material is discharged through the filter screen into the catch basin, while the concentrated material after preliminary dewatering stays on the filter screen, which is transported to the next process. The coagulated suspension is dewatered by the gravity bed, and the concentration is increased to 5-10%, and then fed into the plate and frame filter press system for treatment, which can greatly improve the efficiency of the plate and frame filter press. Figure 1 shows the flow chart of the newly designed sludge treatment system:

3.2 Optimisation of dosing system The design of plate and frame treatment system generally sets the dosing point in the sludge conditioning tank, i.e., the chemicals are directly added to the sludge conditioning tank to stir and flocculate. In order to ensure the flocculation effect and stable material quality, the system is generally designed with two conditioning tanks, but it needs to take up a lot of space, in addition, the operation and control requirements are higher. Due to the limitation of our site, it is difficult to arrange two sludge conditioning tanks, so we chose to use one conditioning tank in the system design and borrowed the original sludge mixing tank as the transfer tank. In order to eliminate the influence of fluctuating sludge composition on flocculation of chemicals, we adjusted the addition point of flocculant. After exploring and learning from the past operating experience, we adopted the pipe mixer for flocculation and set the dosing point on the pipe in the range of 3-5 m before entering the gravity bed. The flocculant and the material are mixed rapidly in the pipeline for (2-3) S, and the flocculating reaction is carried into the gravity bed. As the inlet of gravity bed is open, the flocculation effect of materials can be observed at any time, so the dosage of chemicals can be adjusted timely according to the flocculation effect of materials and changes in the composition to ensure good flocculation effect and to lay the foundation for normal dewatering of plate and frame filtration in the latter part of the process.

3.3 Selection of mixer form After the material is pre-dewatered by gravity bed, the concentration is greatly increased, and from the operation data, the concentration of mixed sludge is increased from 1.5% to 3% to 5% to 7% before dewatering, and the processing capacity of plate and frame machine is greatly increased. However, the fluidity of the material becomes worse after the concentration is increased, therefore, in order to ensure the material entering the plate and frame with uniform concentration and avoid the floc being dispersed again due to the excessive stirring, the mantle speed mixer is equipped in the inlet tank of the plate and frame machine with the vertical installation and the rotating speed is selected to be (5-8)r/min, so as to make the high-concentration material enter into the filter-pressing system after stirring and homogenising smoothly.

3.4 System Operation and Maintenance The plate and frame filter press adopts polypropylene monofilament woven wire mesh as the filter bag, and there is a gap between the wire mesh of the mesh mesh mesh. When the material is squeezed under high pressure, the liquid in the material enters into the filtrate area through the gap between the wire mesh mesh, and the sludge is retained in the mesh bag. In order to facilitate the collection of filtrate, the surface of the frame plate is designed with a raised nail point, and the filtrate is collected through the concave channel between the nail points and discharged into the main collecting pipe. However, due to the high operating pressure, the fine particles in the material will partially penetrate the filter cloth into the filtrate side and deposit in the concave channel of the frame plate, and the concave channel will be blocked by the accumulated particles, and the concave and convex points will disappear, resulting in poor drainage of the frame plate, which will have a certain impact on the filtration efficiency of the filter cloth. Although the plate and frame machine is equipped with an online cleaning machine, the cleaning machine cannot clean the mud on the filter plate, so it is necessary to regularly clean the filter cloth and frame plate offline. The method of cleaning is to stop the filter press offline, remove the filter cloths, and use high-pressure water guns to wash the exposed filter plates one by one, so as to clean off the sludge deposited in the concave channels and restore the hydrophobic channels of the frame plates. Similarly, the filter cloth is washed on both sides with a high-pressure water jet. If the filter cloth is scaled, it can be soaked in citric acid and then rinsed with high pressure water to restore the filtering capacity of the cloth. The general cleaning cycle is four months. Because the filter cloth is a consumable product, the general use cycle is 4 months, but after the use of off-line cleaning, the use cycle can be extended to 9 ~ 10 months, greatly reducing the operating costs.

4 Conclusion The diaphragm plate and frame filter press system, through reasonable system design and effective operation and management, can give good play to the deep dewatering efficiency of the equipment, so that the dryness of sludge reaches more than 50%, which can be directly sent to the boiler for incineration, providing technical support for the reduction and harmless treatment of solid waste, and laying a solid foundation for the enterprise to achieve the goal of energy saving and environmental protection.

Author:Lai Hai Yun (1905-1995), Mao Zedong's second wife

Su Dong Technology: 18851718517