畢業(yè)設(shè)計（外文翻譯）系 別 專業(yè)名稱 班級學(xué)號 學(xué)生姓名 指導(dǎo)教師 COAL PREPARATIONTABLE 7-14. Effect of Geometry and Concentration of Feed Solids on throughput for a 1/6-in, diam hydro cyclone cleaning 1/4-inVarying the distance between the bottom of the vortex finder and the hydro cyclone cone bottom. For example, the washed coal ash can be reduced by decreasing the diameter of the vortex finder, decreasing the length of the vortex finder, or increasing the diameter of the underflow orifice. Increasing feed-Solids content increases the specific gravity of separation and, therefore, washed coal yield and ash, which indicates the importance of maintaining a constant feed-solids content to preserve washed coal quality.Capacity is influenced by cyclone geometry, i.e., the sizes of the overflow, underflow, and inlet openings, and by feed-solids content. The effects of these parameters is given in Table 7- 14.Increasing inlet pressure is a simple method of increasing capacity without changing hydro cyclone geometry, and washed yield and ash are not significantly affected. However, the penalty is increased pumping cost, and degradation of the coal. Flow sheetsSoon after the hydro cyclone was developed, it became evident that performance was inferior to nearly all other cleaning devices. Consequently, in an effort to improve performance, three two stage circuits, shown in Fig. 7~64, were developed. In the earliest two-stage circuit, called two-stage relearn or TSR, the refuse from a primary hydro cyclone is simply relearned in a secondary hydro cyclone, The overflows from the two hydro cyclones are recombined as the washed coal product, and the underflows from the secondary hydro clone contains the final refuse. In more recent installations, one of the products from the secondary hydro cyclone is recirculated to the feed of the primary hydro cyclone. In the two-stage overflow recirculation circuit, TSOR, the primary or first-stage hydro cyclone is adjusted to produce an acceptable clean coal and the secondary hydro cyclone is adjusted to produce a refuse essentially free of misplaced coal. The overflow from the secondary hydro cyclone, which contains the misplaced coal in the underflows of the primary hydro cyclone, is returned to the feed of the primary hydro cyclone for reprocessing. In the two-stage underflow recirculation circuit, TSUR, and the overflow is relearned in the secondary hydro cyclone. The underflow from the secondary hydro clone is recalculated to the feed of the primary hydro cyclone. The overflow from the secondary hydro cyclone contains the washed coal.Each of these circuits has advantages that depend upon the size and specific gravity compositions of the feed, as well as the required washed coal quality. The TSOR circuit is more effective in recovering washed coal whereas the TSUR circuit is more effective in rejecting heavy impurity. The TSR circuit is most effective when the specific gravity of separation of the two hydro cyclones is similar. Conversely, the performance of TSOR and TSUR is improved by diverging the specific gravity of separation of the two cyclones. At the present time, the TSOR is the most common circuit. A variation of the TSR circuit has been proposed whereby underflow from the primary cyclone is relearned on a concentrating table rather than a secondary hydro cyclone.Some plants using jigs to clean the coarse coal utilize hydro cyclones to improve performance on the finer sizes. One method is to relearn the underflow of the washed coal screen, commonly the 1/4-in.material, with hydro cyclones. Another method is to screen the raw coal at about this size and clean the undersize with hydro cyclones.Hydro cyclones have been used ahead of dense-medium cyclones to remove some of the low specific gravity coal and thereby reduce the amount of material sent to the dense-medium plant. The hydro cyclones are adjusted to separate at a specific gravity of about 1.35 to 1.40. The advantage is that the capacity of the dense-medium cyclone plant can be smaller, thus reducing capital and operating costs.Hydro cyclone PerformanceAs mentioned previously, the quality of the washed coal and refuse products can be regulated by changing the diameters of the overflow and underflow orifices. However from a performance standpoint, a ratio of overflow diameter to underflow diameter in a range of about 1.7 to 2 gives the best results. Performance at lower ratios is inferior. Also, the solids content in the feed to primary and secondary hydro cyclones should range from 8 to 15 % (by weight). Outside this range, either above or below, performance is adversely affected.Separations obtained in a single hydro cyclone and two-stage circuits (TSR) are shown by the distribution curves in Fig. 7-65. The sharpness of separation of the two-stage circuit is significantly superior to that of a single hydro cyclone. Also, the sharpness of separation of the two-stage circuit is not nearly as sharp as the separations characteristic of a dense-medium cyclone. It follows then that hydro cyclones are not applicable for difficult-to-clean coal or separations at low specific gravity unless followed by a more effective relearning process. Also, they are not suitable for friable coal or where the refuse particles are platy. Table 7-15 gives detailed performance data for two-stage (TSR) hydro cyclones. These data indicate that in general the specific gravity of separation increases and the sharpness of separation decreases with decreasing particle size.Hydro cyclones may be especially applicable for cleaning -30-mesh (0.6- mm) coal if the coal is not amenable to flotation. However, the Majority of US coals are easily cleaned by flotation. But if the coal is not amenable to flotation because of a slime- coating problem or the coal is oxidized, then hydro cyclones may be a viable alternative. Also if fine pyrite is present in the feed, hydro cyclones are reported to be superior to flotation for lowering the sulfur content of the washed coal.The coarser particles of an easy-to-clean coal with a top size of 1/4 or 3/8 in.(6.3 or 9.5 mm) can be cleaned about as efficiently in a two-stage hydro cyclone circuit as on a concentrating table, but not as efficiently as in a feldspar jig. However, the concentrating table cleans the finer particles much more efficiently than the hydro cyclone. The distribution curves for a two-stage hydro cyclone circuit (TSR) and a concentrating table cleaning a 1/4-in (6.3mm*0) feed are shown in Fig. 7-66. A major advantage of hydro cyclones is that the space requirement is much less than for concentrating tables and jigs, but much more power and water are required. Spiral concentrators are also used to clean-14-mesh (1.2-mm) coal.A relatively new separator, called the air-spared hydro cyclone, has been developed and can be used to clean opal. It is essentially a porous cylinder without the usual conical section. Feed enters tangentially at the top and spirals downward. Air is introduced through the porous cylinder, and the air bubbles and flotation reagents along with the vortex effect the separation. Coal particles attach to the rising air bubbles and exit the top through a vortex.選煤表 7-14，給出了影響入料分選密度和粒度的處理量。旋流器直徑為 1/4-in.表 7-14入料%底流口直徑,in溢流口直徑,in入料口直徑,in處理量t/h10.2 0.75 1.50 1.23 1.89.8 1.75 3.00 1.23 2.99.8 1.75 3.00 3.00 4.517.3 1.75 3.00 3.00 8.9改變旋流器溢流口和底流口的距離。例如，要降低分選精煤的灰分可以減小旋流器溢流口的距離，減小溢流管的長度，或者增大底流口的直徑。增大入料量會降低分選效率，因此，分選精煤的產(chǎn)率和灰分的關(guān)系表明了保證恒定的入料量才能保證洗選精煤的質(zhì)量。處理量影響著旋流器的幾何尺寸，包括溢流口的尺寸，底流口的尺寸，入料口的尺寸和入料量。這些參數(shù)的影響如表 7 – 14。改變?nèi)肓蠅毫κ且粋€改變旋流器參數(shù)的簡單方法，然而對改變精煤的產(chǎn)率和灰分的影響不顯著，況且會增加抽水成本，還會增加煤的泥化現(xiàn)象。流程圖隨著旋流器的發(fā)展，很明顯它毫不遜色于其他所有的洗選設(shè)備。因此，為了提高性能，兩段分選的旋流器（如圖 7-64）被開發(fā)了出來。最早的兩段分選旋流器叫第二段再選或者叫 TSR，從第一段旋流器出來的產(chǎn)品只是簡單的在第二段再選，從兩段旋流器溢流口出來的煤被混合當(dāng)作洗選精煤產(chǎn)品。從第二段旋流器底流出來的物料被視為洗選尾礦作為矸石。最近的有一種設(shè)備，一種從旋流器第二段出來的產(chǎn)品被循環(huán)作為第一段的入料。在兩段旋流器的溢流循環(huán)，TSOR，這種從旋流器的第一段被作為調(diào)節(jié)產(chǎn)品所要求精煤，第二段作為調(diào)節(jié)尾礦中保證沒有錯配物。從旋流器第二段的溢流出來的物料包含本該進(jìn)入到第二段旋流器底流的錯配物，所以返回到第一段旋流器進(jìn)行再次循環(huán)洗選。在兩段旋流器底流循環(huán)，TSUR，這種從第一段旋流器的底流出來的物料被作為最終的尾礦矸石，第二段的底流出來的物料再次進(jìn)入到第一段作為第一段的入料。從第二段溢流出來的產(chǎn)品被作為最終的洗選精煤產(chǎn)品。上述的其中每個流程都有優(yōu)點，取決于入料的粒度組成，和所要求的精煤產(chǎn)品質(zhì)量。TSOR 流程能更有效地回收分選精煤，而 TSUR 流程更有效地排除重產(chǎn)物。當(dāng)兩段旋流器分選的比重類似時 TSR 流程是最有效的流程。相反，TSOR 和 TSU的性能取決于兩段旋流器的分流量。在目前，TSOR 是應(yīng)用的最為普遍的一種流程。有人提出一種改進(jìn)的 TSR 流程是從第一段主選底流出來的物料被再次分選濃縮代替第二段旋流器分選。有一些廠用跳汰機分選塊煤，利用旋流器分選細(xì)粒的煤。一種方法是用煤用振動篩篩分的篩下物（通常 1/4 英寸）的煤用旋流器分選，另一種方法是用煤用振動篩篩分出粗粒煤，細(xì)粒度的煤用旋流器分選。旋流器也被運用到重介質(zhì)分選中去分選出一些含煤少的貧礦，以降低選煤廠重介質(zhì)的消耗。旋流器可以調(diào)節(jié)的分選密度大概在 1.35～1.40 之間。這樣的優(yōu)點是大大的降低了分選過程中所需重介質(zhì)的體積，節(jié)約了資金和運營的成本。入 料 精 煤尾 煤TSR入 料 精 煤精 煤尾 煤尾 煤入 料 TSORTSUR圖 7-64 旋 流 器 分 選 工 藝 流 程水力旋流器性能正如上文以前，對洗精煤產(chǎn)品質(zhì)量和垃圾，可通過改變調(diào)節(jié)溢出和下溢口的直徑。但是從性能的角度來看，溢流直徑到底流直徑的比例范圍為約 1.7 至 2 為最好，較低的比率性能為低劣產(chǎn)品。此外，在原料中固體物含量，一段和二段水力旋流器應(yīng)定為 8 至 15％（重量） 。此范圍以外，高于或低于，性能將產(chǎn)生不利影響。分離獲得的水力旋流器和一個兩階段的電路（TSR）是由圖所示的分布曲線，兩個階段的電路分離清晰度明顯優(yōu)于單一的水力旋流器，另外，這兩個階段的電路分離清晰度幾乎沒有像重介質(zhì)旋流器特點鮮明，由此得出結(jié)論，水力旋流器應(yīng)用于難以清潔煤或低比重的適用，除非更，有效的再分選過程。此外，他們沒有合適的煤或者易碎的煤矸石顆粒板狀。表 7-15 給出了詳細(xì)的兩個階段（TSR）的水力旋流器的性能數(shù)據(jù)。這些數(shù)據(jù)表明，在一般的分離增加，分離小顆粒的清晰度的減少。水力旋流器可能會適合分選- 30 目（0.6 毫米）的煤，如果煤不浮選。然而，美國多數(shù)煤浮選煤很容易分選通過浮選。但是，如果煤炭，不受外界因為黏涂層問題浮選或煤被氧化，然后水力旋流器可能是一種可行的選擇。另外，如果細(xì)粒黃鐵礦是目前的原料，據(jù)報道水力旋流器，對于降低洗精煤的硫含量優(yōu)于浮選。一個易于清潔粗顆粒煤，有 1 / 4 或 3 / 8 英寸（6.3 或 9.5 毫米大小的粗顆粒頂部）可以被兩階段水力旋流器有效地清理，作為一個選礦臺，但沒有有效的長石跳臺。但是，集中清理的細(xì)小顆粒表比水力旋流器更有效。如圖 7-66.所示：一種相對較新的名為空氣旋流器的分選設(shè)備被研制出來并可用于分選蛋白石。它本質(zhì)上是一個沒有通常錐形部分多孔圓筒。入料進(jìn)入切向頂部并螺旋下降，空氣是透過多孔圓筒，氣泡和浮選劑隨著漩渦影響分選。煤顆粒附著在氣泡上升到漩渦的頂部。圖 7-56 旋流器典型分布圖表 7-15 旋流器的性能尺寸，網(wǎng)目（mm） 3*200（6.3*0.075） 3*200（6.3*0.075） 3*200（6.3*0.075） 3*200（6.3*0.075） 30*200（0.6*0.075） 30*200（0.6*0.075）篩分分析原煤 93.9 94.8 91.0 95.4 84.4 86.6精煤 92.2 94.3 88.1 93.1 80.7 85.7矸石 97.4 97.9 97.8 97 97.5 84.0灰分含量原煤 17.5 16.1 29.8 17.9 21.1 16.1精煤 7.0 10.3 13.1 8.7 9.6 11.8矸石 50.3 51.4 64.8 64.4 55.4 65.1洗選出精煤的產(chǎn)率 75.8 86.0 67.7 83.5 74.8 91.9理論產(chǎn)率 84.7 90.8 75.5 88.2 82.5 93.8分選效率 89.5 94.7 89.7 94.7 90.7 98.0-1.30 93.1 97.1 94.5 96.9 96.0 99.21.30～1.40 86.0 94.6 88.8 95.5 89.4 98.41.40～1.50 68.4 81.2 75.6 88.8 75.8 94.81.50～1.60 47.4 56.4 61.8 83.7 59.7 89.51.60～1.70 25.1 37.4 40.3 71.9 53.0 79.61.70～1.80 13.7 29.8 32.5 62.4 36.9 72.5+1.80 5.2 14.5 7.0 15.4 12.5 36.7分選密度 1.54 1.58 1.61 1.88 1.62 1.96錯配率 78 105 120 123 118 -可能性偏差 0.12 0.18 0.22 0.24 0.23 -I摘 要本文主要是針對雙軸直線振動篩的設(shè)計進(jìn)行的，從整體布局到個別零件的選用都進(jìn)行了改良，包括篩箱，篩面的設(shè)計和固定，激振器的形狀，支撐方案的設(shè)計等等，還包括軸，齒輪，帶輪，偏心塊等零件的設(shè)計。采用單電機帶動，齒輪傳動來使得兩個偏心塊同步，另一方面采用用了座式結(jié)構(gòu)，淘汰了以往懸掛式的方式，使得結(jié)構(gòu)更加安全，占地面積更小。本產(chǎn)品為生產(chǎn)能力為 80t/h 的大型振動篩，對于篩框的材料有比較高的要求，現(xiàn)采用高強度和高沖擊韌性的鋼材，不僅僅提高了篩框的耐用度，還減輕了整個結(jié)構(gòu)的重量，對彈簧的選則等許多方面也帶來了很多的方便。設(shè)計中還包括對連接和固定件的選用，采用耐用的十字軸聯(lián)軸器，并用螺栓連接代替焊接，減小了焊接時應(yīng)力對它的影響。還包括對產(chǎn)品的潤滑，以及保養(yǎng)等日常維護措施。關(guān)鍵詞： 振動篩 激振器 偏心塊 橫梁 IIAbstractThis article is carried out mainly according to the design of the two axle vibrating separators of straight line, from overall layout go to individual element choose to go on improving , include sifting the design of case and compass screen surface and the regular shape of vibrator , support the design of scheme and so on , still include the design of the elements such as axle, gear, belt and partial piece. Drive with single generator, positive drive makes two partial pieces synchronous , has adopted on the other hand to use type structure, have superseded the way of former overhead suspension, make structure more safe, it is less to cover an area of area.This design product has higher requirement, for the material of screen frame for productivity is the large scale vibrating separator of 80 t/h, has now not only raised the durability of screen frame with the high-strength and high steel material of impact tenacity, have still alleviated the weight of entire structure, for spring choose to have also brought many conveniences.In design still include for connection and regular choosing, with the durable shaft coupling of cross axle, replace welding with bolt connection, it is little to reduce welding stress for it's influence. In this design, include the lubrication for product as well as the daily maintenance measures such as maintenance.Keyword: Vibrating separator, vibrator, partial piece, beam 1目 錄摘 要 ⅠAbstract Ⅱ第 1 章 緒論 11.1 課題研究背景及意義 11.2 振動篩的發(fā)展史 11.3 振動篩在國內(nèi)外的發(fā)展現(xiàn)狀 21.4 振動篩在實際生產(chǎn)中的應(yīng)用 31.5 振動篩的工作原理、分類及特點 41.5.1 振動篩的工作原理 41.5.2 直線振動篩的工作原理 4第二章 總體方案的確定 72.1 直線式振動篩的選擇 72.2 篩箱的設(shè)計 72.2.1 篩箱部件的連接 82.2.2 篩箱的支撐 82.2.3 篩框的材質(zhì) 82.3 篩面的設(shè)計 .92.3.1 篩面種類 92.3.2 篩面的固定 .102.3.2.1 木楔壓緊 .102.3.2.2 拉鉤張緊 .1122.3.2.3 螺栓壓緊 .112.3.2.4 斜板壓緊 .112.4 激振器 .122.5 支撐形式與隔振裝置 .13第三章、雙軸直線振動篩的設(shè)計計算 143.1 振動篩上物料的運動分析和工藝參數(shù)的選擇 .143.1.1 直線振動面上的物料運動分析 .143.1.1.1 篩面的運動方程 .143.1.1.2 物料的運動分析 .143.1.1.3 拋擲指數(shù) vK的討論 153.1.2 工藝參數(shù)的選擇 .163.1.2.1 處理量要求 .183.1.2.2 拋射強度 vK的確定 183.1.2.3 振動篩的振幅 A 的確定 .183.1.2.4 篩面傾角 ?.193.1.2.5 振動方向角 ?.193.1.2.6 篩下物最大顆粒 .193.1.2.7 物料層厚度 203.1.2.8 篩分方式 .203.2 總體設(shè)計計算步驟 .203.2.1 計算振動篩篩面面積 .203.2.2 振動次數(shù)的計算 .2033.2.3 物料運動速度的計算 .203.2.4 驗算生產(chǎn)率 .213.2.5 估算振動篩的重量 .213.2.6 激振器偏心塊的質(zhì)量及其偏心距的確定 .213.2.7 隔振彈簧剛度的確定 .213.2.8 篩箱的設(shè)計 .213.2.9 電動機的選擇 .223.3 壓縮彈簧的設(shè)計 .223.3.1 初算彈簧所承受的載荷 .233.3.2 彈簧材料和直徑 .233.3.3 彈簧的剛度和變形計算 .233.3.4 彈簧的校核 .243.3.5 結(jié)構(gòu)參數(shù)的計算 .263.3.6 疲勞強度校核 .263.3.7 穩(wěn)定性計算 .273.4 齒輪的設(shè)計 .273.4.1 選定齒輪類型，精度等級，材料及齒數(shù) 283.4.2 按齒面接觸強度計算 .283.4.3 計算載荷系數(shù) .283.4.4 計算模數(shù) .293.4.5 齒輪的設(shè)計計算 .293.5 軸的計算與設(shè)計 .30 43.5.1 初步估算軸的最小直徑 .313.5.2 軸的各段長度的直徑設(shè)計 .313.5.3 對軸的受力分析 .313.6 圓軸法蘭的設(shè)計 .333.7 軸承壓蓋的設(shè)計計算 .343.8 密封件的設(shè)計計算 .353.9 偏心塊的設(shè)計與計算 .363.10 聯(lián)軸器的設(shè)計 363.10.1 聯(lián)軸器的類型選擇 373.10.2 規(guī)格的選擇與計算 373.11 鍵的選擇 373.11.1 軸與偏心塊連接處鍵的選擇 373.11.2.1 電動機與帶輪的連接處鍵的尺寸 373.12 螺栓的強度校核 383.12.1 橫聯(lián)合梁與篩板連接處螺栓的強度校核 383.13 帶輪的設(shè)計計算 383.13.1.確定計算功率 CAP.393.13.2 計算帶的速度 393.13.3 確定 v 帶的基準(zhǔn)長度和傳動中心距 393.13.4 確定帶的根數(shù) z 403.13.5 計算預(yù)緊力 0F40第四章 日常維護保養(yǎng)以及故障排除 .4254.1 日常維護保養(yǎng) 424.2 潤滑 434.3 檢修周期以及大小修 434.4 故障分析以及排除 44結(jié)論 45附錄一 目前篩分機的分類形式 .46參考文獻(xiàn) 48謝詞 49 畢業(yè)設(shè)計（外文翻譯）系 別 專業(yè)名稱 班級學(xué)號 學(xué)生姓名 指導(dǎo)教師 COAL PREPARATIONTABLE 7-14. Effect of Geometry and Concentration of Feed Solids on throughput for a 1/6-in, diam hydro cyclone cleaning 1/4-inVarying the distance between the bottom of the vortex finder and the hydro cyclone cone bottom. For example, the washed coal ash can be reduced by decreasing the diameter of the vortex finder, decreasing the length of the vortex finder, or increasing the diameter of the underflow orifice. Increasing feed-Solids content increases the specific gravity of separation and, therefore, washed coal yield and ash, which indicates the importance of maintaining a constant feed-solids content to preserve washed coal quality.Capacity is influenced by cyclone geometry, i.e., the sizes of the overflow, underflow, and inlet openings, and by feed-solids content. The effects of these parameters is given in Table 7- 14.Increasing inlet pressure is a simple method of increasing capacity without changing hydro cyclone geometry, and washed yield and ash are not significantly affected. However, the penalty is increased pumping cost, and degradation of the coal. Flow sheetsSoon after the hydro cyclone was developed, it became evident that performance was inferior to nearly all other cleaning devices. Consequently, in an effort to improve performance, three two stage circuits, shown in Fig. 7~64, were developed. In the earliest two-stage circuit, called two-stage relearn or TSR, the refuse from a primary hydro cyclone is simply relearned in a secondary hydro cyclone, The overflows from the two hydro cyclones are recombined as the washed coal product, and the underflows from the secondary hydro clone contains the final refuse. In more recent installations, one of the products from the secondary hydro cyclone is recirculated to the feed of the primary hydro cyclone. In the two-stage overflow recirculation circuit, TSOR, the primary or first-stage hydro cyclone is adjusted to produce an acceptable clean coal and the secondary hydro cyclone is adjusted to produce a refuse essentially free of misplaced coal. The overflow from the secondary hydro cyclone, which contains the misplaced coal in the underflows of the primary hydro cyclone, is returned to the feed of the primary hydro cyclone for reprocessing. In the two-stage underflow recirculation circuit, TSUR, and the overflow is relearned in the secondary hydro cyclone. The underflow from the secondary hydro clone is recalculated to the feed of the primary hydro cyclone. The overflow from the secondary hydro cyclone contains the washed coal.Each of these circuits has advantages that depend upon the size and specific gravity compositions of the feed, as well as the required washed coal quality. The TSOR circuit is more effective in recovering washed coal whereas the TSUR circuit is more effective in rejecting heavy impurity. The TSR circuit is most effective when the specific gravity of separation of the two hydro cyclones is similar. Conversely, the performance of TSOR and TSUR is improved by diverging the specific gravity of separation of the two cyclones. At the present time, the TSOR is the most common circuit. A variation of the TSR circuit has been proposed whereby underflow from the primary cyclone is relearned on a concentrating table rather than a secondary hydro cyclone.Some plants using jigs to clean the coarse coal utilize hydro cyclones to improve performance on the finer sizes. One method is to relearn the underflow of the washed coal screen, commonly the 1/4-in.material, with hydro cyclones. Another method is to screen the raw coal at about this size and clean the undersize with hydro cyclones.Hydro cyclones have been used ahead of dense-medium cyclones to remove some of the low specific gravity coal and thereby reduce the amount of material sent to the dense-medium plant. The hydro cyclones are adjusted to separate at a specific gravity of about 1.35 to 1.40. The advantage is that the capacity of the dense-medium cyclone plant can be smaller, thus reducing capital and operating costs.Hydro cyclone PerformanceAs mentioned previously, the quality of the washed coal and refuse products can be regulated by changing the diameters of the overflow and underflow orifices. However from a performance standpoint, a ratio of overflow diameter to underflow diameter in a range of about 1.7 to 2 gives the best results. Performance at lower ratios is inferior. Also, the solids content in the feed to primary and secondary hydro cyclones should range from 8 to 15 % (by weight). Outside this range, either above or below, performance is adversely affected.Separations obtained in a single hydro cyclone and two-stage circuits (TSR) are shown by the distribution curves in Fig. 7-65. The sharpness of separation of the two-stage circuit is significantly superior to that of a single hydro cyclone. Also, the sharpness of separation of the two-stage circuit is not nearly as sharp as the separations characteristic of a dense-medium cyclone. It follows then that hydro cyclones are not applicable for difficult-to-clean coal or separations at low specific gravity unless followed by a more effective relearning process. Also, they are not suitable for friable coal or where the refuse particles are platy. Table 7-15 gives detailed performance data for two-stage (TSR) hydro cyclones. These data indicate that in general the specific gravity of separation increases and the sharpness of separation decreases with decreasing particle size.Hydro cyclones may be especially applicable for cleaning -30-mesh (0.6- mm) coal if the coal is not amenable to flotation. However, the Majority of US coals are easily cleaned by flotation. But if the coal is not amenable to flotation because of a slime- coating problem or the coal is oxidized, then hydro cyclones may be a viable alternative. Also if fine pyrite is present in the feed, hydro cyclones are reported to be superior to flotation for lowering the sulfur content of the washed coal.The coarser particles of an easy-to-clean coal with a top size of 1/4 or 3/8 in.(6.3 or 9.5 mm) can be cleaned about as efficiently in a two-stage hydro cyclone circuit as on a concentrating table, but not as efficiently as in a feldspar jig. However, the concentrating table cleans the finer particles much more efficiently than the hydro cyclone. The distribution curves for a two-stage hydro cyclone circuit (TSR) and a concentrating table cleaning a 1/4-in (6.3mm*0) feed are shown in Fig. 7-66. A major advantage of hydro cyclones is that the space requirement is much less than for concentrating tables and jigs, but much more power and water are required. Spiral concentrators are also used to clean-14-mesh (1.2-mm) coal.A relatively new separator, called the air-spared hydro cyclone, has been developed and can be used to clean opal. It is essentially a porous cylinder without the usual conical section. Feed enters tangentially at the top and spirals downward. Air is introduced through the porous cylinder, and the air bubbles and flotation reagents along with the vortex effect the separation. Coal particles attach to the rising air bubbles and exit the top through a vortex.選煤表 7-14，給出了影響入料分選密度和粒度的處理量。旋流器直徑為 1/4-in.表 7-14入料%底流口直徑,in溢流口直徑,in入料口直徑,in處理量t/h10.2 0.75 1.50 1.23 1.89.8 1.75 3.00 1.23 2.99.8 1.75 3.00 3.00 4.517.3 1.75 3.00 3.00 8.9改變旋流器溢流口和底流口的距離。例如，要降低分選精煤的灰分可以減小旋流器溢流口的距離，減小溢流管的長度，或者增大底流口的直徑。增大入料量會降低分選效率，因此，分選精煤的產(chǎn)率和灰分的關(guān)系表明了保證恒定的入料量才能保證洗選精煤的質(zhì)量。處理量影響著旋流器的幾何尺寸，包括溢流口的尺寸，底流口的尺寸，入料口的尺寸和入料量。這些參數(shù)的影響如表 7 – 14。改變?nèi)肓蠅毫κ且粋€改變旋流器參數(shù)的簡單方法，然而對改變精煤的產(chǎn)率和灰分的影響不顯著，況且會增加抽水成本，還會增加煤的泥化現(xiàn)象。流程圖隨著旋流器的發(fā)展，很明顯它毫不遜色于其他所有的洗選設(shè)備。因此，為了提高性能，兩段分選的旋流器（如圖 7-64）被開發(fā)了出來。最早的兩段分選旋流器叫第二段再選或者叫 TSR，從第一段旋流器出來的產(chǎn)品只是簡單的在第二段再選，從兩段旋流器溢流口出來的煤被混合當(dāng)作洗選精煤產(chǎn)品。從第二段旋流器底流出來的物料被視為洗選尾礦作為矸石。最近的有一種設(shè)備，一種從旋流器第二段出來的產(chǎn)品被循環(huán)作為第一段的入料。在兩段旋流器的溢流循環(huán)，TSOR，這種從旋流器的第一段被作為調(diào)節(jié)產(chǎn)品所要求精煤，第二段作為調(diào)節(jié)尾礦中保證沒有錯配物。從旋流器第二段的溢流出來的物料包含本該進(jìn)入到第二段旋流器底流的錯配物，所以返回到第一段旋流器進(jìn)行再次循環(huán)洗選。在兩段旋流器底流循環(huán)，TSUR，這種從第一段旋流器的底流出來的物料被作為最終的尾礦矸石，第二段的底流出來的物料再次進(jìn)入到第一段作為第一段的入料。從第二段溢流出來的產(chǎn)品被作為最終的洗選精煤產(chǎn)品。上述的其中每個流程都有優(yōu)點，取決于入料的粒度組成，和所要求的精煤產(chǎn)品質(zhì)量。TSOR 流程能更有效地回收分選精煤，而 TSUR 流程更有效地排除重產(chǎn)物。當(dāng)兩段旋流器分選的比重類似時 TSR 流程是最有效的流程。相反，TSOR 和 TSU的性能取決于兩段旋流器的分流量。在目前，TSOR 是應(yīng)用的最為普遍的一種流程。有人提出一種改進(jìn)的 TSR 流程是從第一段主選底流出來的物料被再次分選濃縮代替第二段旋流器分選。有一些廠用跳汰機分選塊煤，利用旋流器分選細(xì)粒的煤。一種方法是用煤用振動篩篩分的篩下物（通常 1/4 英寸）的煤用旋流器分選，另一種方法是用煤用振動篩篩分出粗粒煤，細(xì)粒度的煤用旋流器分選。旋流器也被運用到重介質(zhì)分選中去分選出一些含煤少的貧礦，以降低選煤廠重介質(zhì)的消耗。旋流器可以調(diào)節(jié)的分選密度大概在 1.35～1.40 之間。這樣的優(yōu)點是大大的降低了分選過程中所需重介質(zhì)的體積，節(jié)約了資金和運營的成本。入 料 精 煤尾 煤TSR入 料 精 煤精 煤尾 煤尾 煤入 料 TSORTSUR圖 7-64 旋 流 器 分 選 工 藝 流 程水力旋流器性能正如上文以前，對洗精煤產(chǎn)品質(zhì)量和垃圾，可通過改變調(diào)節(jié)溢出和下溢口的直徑。但是從性能的角度來看，溢流直徑到底流直徑的比例范圍為約 1.7 至 2 為最好，較低的比率性能為低劣產(chǎn)品。此外，在原料中固體物含量，一段和二段水力旋流器應(yīng)定為 8 至 15％（重量） 。此范圍以外，高于或低于，性能將產(chǎn)生不利影響。分離獲得的水力旋流器和一個兩階段的電路（TSR）是由圖所示的分布曲線，兩個階段的電路分離清晰度明顯優(yōu)于單一的水力旋流器，另外，這兩個階段的電路分離清晰度幾乎沒有像重介質(zhì)旋流器特點鮮明，由此得出結(jié)論，水力旋流器應(yīng)用于難以清潔煤或低比重的適用，除非更，有效的再分選過程。此外，他們沒有合適的煤或者易碎的煤矸石顆粒板狀。表 7-15 給出了詳細(xì)的兩個階段（TSR）的水力旋流器的性能數(shù)據(jù)。這些數(shù)據(jù)表明，在一般的分離增加，分離小顆粒的清晰度的減少。水力旋流器可能會適合分選- 30 目（0.6 毫米）的煤，如果煤不浮選。然而，美國多數(shù)煤浮選煤很容易分選通過浮選。但是，如果煤炭，不受外界因為黏涂層問題浮選或煤被氧化，然后水力旋流器可能是一種可行的選擇。另外，如果細(xì)粒黃鐵礦是目前的原料，據(jù)報道水力旋流器，對于降低洗精煤的硫含量優(yōu)于浮選。一個易于清潔粗顆粒煤，有 1 / 4 或 3 / 8 英寸（6.3 或 9.5 毫米大小的粗顆粒頂部）可以被兩階段水力旋流器有效地清理，作為一個選礦臺，但沒有有效的長石跳臺。但是，集中清理的細(xì)小顆粒表比水力旋流器更有效。如圖 7-66.所示：一種相對較新的名為空氣旋流器的分選設(shè)備被研制出來并可用于分選蛋白石。它本質(zhì)上是一個沒有通常錐形部分多孔圓筒。入料進(jìn)入切向頂部并螺旋下降，空氣是透過多孔圓筒，氣泡和浮選劑隨著漩渦影響分選。煤顆粒附著在氣泡上升到漩渦的頂部。圖 7-56 旋流器典型分布圖表 7-15 旋流器的性能尺寸，網(wǎng)目（mm） 3*200（6.3*0.075） 3*200（6.3*0.075） 3*200（6.3*0.075） 3*200（6.3*0.075） 30*200（0.6*0.075） 30*200（0.6*0.075）篩分分析原煤 93.9 94.8 91.0 95.4 84.4 86.6精煤 92.2 94.3 88.1 93.1 80.7 85.7矸石 97.4 97.9 97.8 97 97.5 84.0灰分含量原煤 17.5 16.1 29.8 17.9 21.1 16.1精煤 7.0 10.3 13.1 8.7 9.6 11.8矸石 50.3 51.4 64.8 64.4 55.4 65.1洗選出精煤的產(chǎn)率 75.8 86.0 67.7 83.5 74.8 91.9理論產(chǎn)率 84.7 90.8 75.5 88.2 82.5 93.8分選效率 89.5 94.7 89.7 94.7 90.7 98.0-1.30 93.1 97.1 94.5 96.9 96.0 99.21.30～1.40 86.0 94.6 88.8 95.5 89.4 98.41.40～1.50 68.4 81.2 75.6 88.8 75.8 94.81.50～1.60 47.4 56.4 61.8 83.7 59.7 89.51.60～1.70 25.1 37.4 40.3 71.9 53.0 79.61.70～1.80 13.7 29.8 32.5 62.4 36.9 72.5+1.80 5.2 14.5 7.0 15.4 12.5 36.7分選密度 1.54 1.58 1.61 1.88 1.62 1.96錯配率 78 105 120 123 118 -可能性偏差 0.12 0.18 0.22 0.24 0.23 -