2757 刮板輸送機(jī)設(shè)計(jì)

2757 刮板輸送機(jī)設(shè)計(jì),輸送,設(shè)計(jì) 英文原文Analysis and Precautions of Chain BreakageFailure of Scraper Conveyors1. ForewordScraper conveyor the fault, the failure to bound rupture the most prominent, and deal with the time spent by the labor intensity and also the largest. Maintenance often found that the chain of serious wear, the end of a chain of non-normal damage and a pit, and other phenomena. This paper analyses the reasons for the failure occurred, by preventive measures.2. analysisAccording to statistics, in the normal production of fully mechanized coal face, scraper conveyor chain conveyor failure time about the failure of more than 40 percent of the time. Ring linked bound rupture major fault caused by the following aspects(1) improper installation1) in the double-stranded different lengths. Under normal circumstances, single ≥ 200 kW power both in the use of double-stranded form, the new procurement scraper conveyor chain at the initial stage when there is no inconsistency in the length of the chain problem, because after the use of conveyor-bending level was advancing, through the chain A longer period of time after use,In the lateral (side-wall coal face) relative elongation of the chain, concentrated load, the heavy start-up occurred when bound rupture vulnerable. When the conveyor face again the next installation, assembly chain may be confusing, if short-chain installed in the lateral and medial in the long-chain equipment, conveyor work will result in biting sprocket chain, with a loose chain Sprocket was bitten and seriously so that when the chain pull off.2) chain link seam down. For the double-stranded conveyor at the time of installation in the Central Weld legislation must be progressive, to reduce wear Weld, extended chain link life; chain link Weld and reduce the friction and wear of the plate. However, in actual use, since the chain link wrong equipment, chain link seam down, and the frequent occurrence bound rupture fault.3) the use of short-scraper. As manufacturing quality problems or wear overrun by the use of the scraper, which, resulting in failure to stop production.4) rack deformation. Sprocket and rack itself allowed the rocky ledge of 5 mm, but the actual rocky ledge in excess of this value, sprocket and chain link connection is bad, a point contact, causing ring linked with the arc of Waterloo sprocket chain of non-normal wear and tear , A pit.5) nose to install high enough. When the nose to install high enough, the head drum Coal Unloader not due to the net, at the end of floating coal will be linked into the groove (that is, turn coal), an increase of the conveyor running resistance and increase the chain, the chute wear, So that the chain tension increased, bound rupture.(2) the use of improper maintenance1) sprocket transition wear. According to a point of order, ≥ 22 mm pitch of the biggest sprocket wear should be ≤ 6 mm (with the roundabout at sprocket chain-linked ring on the inspection and wheel above the distance), six months after the sprocket should use the nose, tail Sprocket to swap. However, in actual use, because of maintenance and use of cost considerations, the sprocket wear still in use, ring linked through the chain wheel when the slide because of the relative squeeze caused friction with the arc of the chain ring wear, and linked Waterloo Ring linked connection is bad, sprocket chain and ring pitch from the chain of non-aggravated the normal wear and tear.2) chain too tight or too loose. Tight at the beginning of the chain tension adjustment is too large, impact on conveyor normal work, shorten the chain of life, exacerbated by the board in the chain and wear, especially when the scratch card scraper, so that the chain elongation. When the chain-scraper, under the nose of a scraper sprocket chain piled up in the chain to interfere with, or even bite chain.3) and vertical degrees of bending gauge. Conveyor passage in the process, the level of the overrun is often due to face rugged, vertical degrees can not be fully guaranteed. Under such circumstances, the inevitable wear ring linked the increase of chain elongation increase.4) fault encountered at the engine frame. As the underground working conditions constantly changing, Shearer cut off layer, cut parting cases have occurred, then the waste water mixed with a cement-like, scraper, and the chain plate in the role of friction, wear the chain of intensified, More than normal wear and tear of coal condition, Sawtooth Central, Weld life cut short, the whole chain of life decline.5) Other damage. Electrical overload started, the running load will cause damage to link Central and bound rupture; began production in the face, cut in the bolt, metal scrap, etc. into the chute, resulting in biting card bound rupture; tight chain method is not correct , Will cause tension gauge and bound rupture(3) quality is not highCircle chain design load is about the broken scraper can withstand the tension about 10 times that in normal circumstances great safety factor, is not going to happen the bound rupture. However, due to various reasons, the ring chain (Sawtooth Central) less than the quality of standards, resulting in the production chain in the ring in bound rupture3 Ring linked Circle as a scraper conveyor chain of traction, its tensile strength directly related to the reliability of. At present, China's largest ring linked to φ42 mm × 146mm compact chain, tensile strength of 2270 kN, the largest foreign ring linked to φ48 mm × 152mm compact chain, tensile strength of 3550 kN. With the ring linked the increasing size of the central trough of higher and higher, conveyor magnificent performance declined, the gateway if not thorough clean-up will also affect passage of conveyor. So ring linked the direction of development is to improve tensile strength and reduce the high degree of Central legislation.3.1 Materials and Technology In order to improve the roundabout chain of tensile strength, the current foreign Grade C and D-linked ring in the large-sized materials with 23 MnNiCrMo54, 23MnNiCrMo54 and 23 MnNiCrMo64 scouring steel, tensile strength limit ≥ 1600 ~ 1800 MPa. Welding Technology: the use of advanced welding equipment, welding and the use of flash returns processing technology, successfully resolved the surfacing of the process of overheating, such as a burning issue. In quality testing, the use of scanning stretch fracture fracture of cables used to pre-tension ring linked to strengthen technology, greatly enhancing the carrying capacity and fatigue.3.2 form and geometry In 1985 the first to create a company 38 mm × 137mm flat chain. Flat is linked each of the chain is still ring-Central, Central was "squeezed" the flat ring. Flat chain link sliding work to reduce the size of the increase in the chain of slot pressure on the units and improve the legislation of the Central wear resistance; reduce its high level of the chain more easily through the sprocket, but can also reduce the capacity of power transmission and Bays of a high degree. Modern high-performance conveyor are generally involved in supporting a flat chain. Figure 5 conventional chain and a new wide-body linked flatIn 2003, the company has developed a wide-body at a flat linked, as shown in Figure 5. It is a high-intensity, low-chain, has the following characteristics:⑴ using this chain can reduce the high scraper chain, thereby reducing the central trough height, eventually reduce the use of high-mining, coal mining to meet thin. ⑵ using this chain can reduce the use of power, or power in the same circumstances, increase the length of face, it will greatly reduce the workload of opening up, reducing the number of face move.⑶ this forging of wide-body flat link chain has increased the contact area, can improve the chain link at the same time reduce the intensity of the wear and helps to maintain the rigidity of chain link. Such as a flat 42 mm chain can take 2 × 855kW of installed power, and 50 mm wide-body flat can be linked up to 3 × 1000kW bear the installed power.3.3 intelligent conveyor chain As unable to accurately predict the failure of the chain, according to conventional practices are generally ahead of the replacement of the chain. In 2005 a company with a number of research institutes to study the development of a conveyor chain-detection system, as shown in Figure 6. This is a combination of integrated sensor technology of intelligent conveyor chain, it will stress the chain of real-time record, the help of micro-electronics technology devices, from computers that the chain of life remaining before the fracture. It also can detect the preloads of the chain, is conducive to life during the period in the chain to achieve the best use of state, improve safety and avoid accidents.4. bound rupture fault approach(1) off on the single-chain: a single chain on bound rupture, the first clean pile of coal on the conveyor, reversing open space will be open to the bound rupture near the tail, and then use the brake, linked resistance (or monomer Pillar), and other tools so that the chain has some margin, with links connecting the ring will be broken;(2) off the double-stranded: in the double-stranded bound rupture, the first clean conveyor on the heap of coal, materials, winch wire rope leash on the lower part of the first chain to pull the tail direction, with open space will be reversed to open the bound rupture Near the tail, and then use the brake, linked resistance (or single prop), and other tools so that the chain has some margin, with links connecting the ring will be broken, or prepared the same length of the chain will bound rupture replaced;(3) off the double-stranded: in the double-stranded bound rupture, the first clean conveyor on the heap of coal, from the estimated bound rupture open multiple skylights to find bound rupture position; materials Road winch wire rope from the tail of the first lower plate Nose to the direction of penetration, with skylights, has been sent to wire rope bound rupture, leash on the lower part of the first chain to pull the tail direction, with open space vehicles will be bound rupture Department is open to the vicinity of the tail,Recycling-oriented chain pulley will be led by the head to the tail of the board above the trough of the transition; reuse winch wire rope will lead to decapitation above the tail, and then use the brake, linked resistance (or single prop), and other tools so that the chain Have a certain margin, with links connecting the ring will be broken, or prepared the same length of the chain will bound rupture replacement.5. bound rupture fault preventive measures(1) strictly control the quality of the installation1) installation, they should point-components, according to the order to install loading transport, to prevent the components were insufficient to replace the old;2) all eyes on the face plate processing (in particular, will be cleared of scrap metal) to determine the nose, tail position, while the installation of the nose should be set aside or highly processed to meet the mounting height to prevent the installation of the wrong location Need to co-opt parts, or for unloading high enough damage to the chain;3) require the installation of the equipment, fastening bolts scraper, with the anti-chain, the scraper must be reworked;4) The installation process is prohibited frequent point vehicles, to avoid components, parts damaged.(2) to enhance equipment maintenance and management1) equipment in the operation to eliminate the use of unqualified chain link ring;2) the strict requirements of pushing wandering step over and over bending; Shearer asked the driver to control roof and floor to prevent a floor-level, to prevent conveyor overload;3) when the chain tight to prevent the chain too tight or too loose;4) the use of the old chain, such as the length of the chain should be tied up in pairs to use, if unable to find the same length of chain, the long chain can be disconnected from the two bundled into use, ranging from the length of the chain mix is prohibited, prohibited the use of breaking strength Not enough chain;5) of the periodic maintenance sentinel system, as required periodic replacement of the tail sprocket nose, to reduce the wear chain and sprocket.(3) improve the quality of technical workers, according to many years of experience, who after training in the installation of the work of the staff, efficient and reworked the low rate, the conveyor failure rate is also low. Therefore only strengthen training and improve the quality of technical workers, in order to prevent the occurrence of an abnormal failure to reduce the incidence of insecurity and improve the economic benefits of coal mine production.中文譯文 刮板輸送機(jī)斷鏈故障分析及防范措施1. 前言刮板輸送機(jī)出現(xiàn)的故障中,以斷鏈故障最為突出,處理時(shí)所花費(fèi)的時(shí)間及勞動(dòng)強(qiáng)度也最大。檢修經(jīng)常會(huì)發(fā)現(xiàn)鏈條嚴(yán)重磨損、鏈條外端部有非正常損壞并出現(xiàn)凹坑等現(xiàn)象。本文分析故障發(fā)生的原因,提出防范措施。2.　分析據(jù)統(tǒng)計(jì),在正常生產(chǎn)的綜采工作面,刮板輸送機(jī)鏈條故障時(shí)間約占輸送機(jī)總故障時(shí)間的40%以上。圓環(huán)鏈斷鏈故障主要由以下幾個(gè)方面引起:(1) 安裝不當(dāng)1) 中雙鏈長(zhǎng)短不一。一般情況下,單機(jī)功率≥200kW時(shí)均采用中雙鏈形式,新采購(gòu)的刮板輸送機(jī)鏈條在初期使用時(shí)不存在鏈條長(zhǎng)短不一致的問(wèn)題,使用后由于輸送機(jī)呈臺(tái)階形彎曲推進(jìn),鏈條經(jīng)過(guò)較長(zhǎng)一段時(shí)間的使用后,處于外側(cè)(工作面煤壁側(cè))的鏈條相對(duì)伸長(zhǎng),集中載荷,在重載起動(dòng)時(shí)極易發(fā)生斷鏈。當(dāng)該輸送機(jī)在下一個(gè)工作面再次安裝使用時(shí),鏈條可能混亂裝配,如果短鏈裝在外側(cè),長(zhǎng)鏈裝在內(nèi)側(cè),輸送機(jī)工作時(shí)將造成外鏈過(guò)緊咬鏈輪、內(nèi)鏈過(guò)松被鏈輪咬,嚴(yán)重時(shí)使鏈條拉斷。2) 鏈環(huán)焊縫向下。對(duì)于中雙鏈輸送機(jī)在安裝時(shí)立環(huán)焊縫必須向上,以減少焊縫磨損,延長(zhǎng)鏈環(huán)壽命;并可減少鏈環(huán)焊縫對(duì)中板的摩擦磨損。但在實(shí)際使用中,由于鏈環(huán)錯(cuò)裝,鏈環(huán)焊縫向下,而發(fā)生頻繁斷鏈故障。3) 使用短刮板。由于制造質(zhì)量問(wèn)題或因使用磨損超限的刮板,致使,造成故障而停止生產(chǎn)。4) 機(jī)架變形。鏈輪與機(jī)架本身允許有5mm的竄動(dòng)量,但當(dāng)實(shí)際竄動(dòng)量超過(guò)此值,鏈輪與鏈環(huán)接觸不良,出現(xiàn)點(diǎn)接觸,造成圓環(huán)鏈圓弧段與鏈輪鏈窩的非正常磨損,出現(xiàn)凹坑。5) 機(jī)頭安裝高度不夠。當(dāng)機(jī)頭安裝高度不夠時(shí),機(jī)頭滾筒由于卸煤不凈,底鏈將浮煤拉入下槽(即回頭煤) ,增加了輸送機(jī)的運(yùn)行阻力,增大了鏈條、溜槽的磨損量,使鏈條張力增大,斷鏈。(2) 使用維護(hù)不當(dāng)1) 鏈輪過(guò)渡磨損。根據(jù)規(guī)程,節(jié)距≥22mm的鏈輪最大磨損量應(yīng)≤6mm (用圓環(huán)鏈平置于鏈輪上檢查圓環(huán)鏈上面與輪轂的距離) ,鏈輪使用半年后應(yīng)將機(jī)頭、機(jī)尾鏈輪進(jìn)行調(diào)換。但在實(shí)際使用中,由于考慮維修和使用成本、磨損嚴(yán)重的鏈輪仍在使用,圓環(huán)鏈在通過(guò)鏈輪時(shí)由于相對(duì)滑動(dòng)摩擦與擠壓而造成圓環(huán)鏈圓弧段磨損,鏈窩與圓環(huán)鏈接觸不良、鏈輪與圓環(huán)鏈節(jié)距不等加劇了鏈條的非正常磨損。2) 鏈子過(guò)緊或過(guò)松。在緊鏈時(shí)初張力調(diào)整過(guò)大,影響輸送機(jī)正常工作,縮短了鏈條的使用壽命,加劇了鏈條與中板的磨損量,特別是當(dāng)刮板被刮卡時(shí),使外鏈伸長(zhǎng)。當(dāng)刮板鏈過(guò)松時(shí),在機(jī)頭鏈輪下造成刮板鏈條堆積,發(fā)生與鏈條干涉,甚至啃咬鏈條。3) 彎曲度和垂直度超限。輸送機(jī)在推移過(guò)程中,水平度超限是經(jīng)常發(fā)生的; 由于工作面凹凸不平,垂直度也不能完全保證。在這種情況下,圓環(huán)鏈必然磨損增大,外鏈伸長(zhǎng)加大。4) 遇到斷層時(shí)拉矸石。由于井下工作條件的不斷變化,采煤機(jī)割斷層、割?yuàn)A矸情況時(shí)有發(fā)生,此時(shí)的矸石與水相混合形成水泥狀,在刮板、鏈條與中板摩擦作用下,鏈條磨損加劇,磨損量超過(guò)正常運(yùn)煤工況,鋸齒環(huán)、焊縫壽命減短,鏈條整體壽命下降。5) 其它損壞。電機(jī)過(guò)負(fù)荷啟動(dòng)、過(guò)負(fù)荷運(yùn)行將造成鏈接環(huán)損壞而斷鏈;在工作面開(kāi)始生產(chǎn)時(shí),切眼內(nèi)的錨桿、金屬?gòu)U料等拉入溜槽,造成蹩卡而斷鏈;緊鏈方法不正確,也會(huì)造成張緊力超限而斷鏈。(3) 質(zhì)量不高圓環(huán)鏈設(shè)計(jì)的破斷載荷約為刮板可承受拉力的10倍左右,在正常情況下安全系數(shù)很大,是不會(huì)發(fā)生斷鏈的。但由于種種原因,圓環(huán)鏈(鋸齒環(huán))的質(zhì)量達(dá)不到標(biāo)準(zhǔn),致使在生產(chǎn)中圓環(huán)鏈發(fā)生斷鏈。3 圓環(huán)鏈圓環(huán)鏈作為刮板輸送機(jī)的牽引機(jī)構(gòu)，其抗拉強(qiáng)度直接關(guān)系到整機(jī)的可靠性。目前，國(guó)產(chǎn)圓環(huán)鏈最大到 φ42mm×146mm 緊湊鏈，抗拉強(qiáng)度為2270kN，國(guó)外圓環(huán)鏈最大到 φ48mm×152mm 緊湊鏈，抗拉強(qiáng)度為3550kN。隨著圓環(huán)鏈尺寸的不斷增大，中部槽也越來(lái)越高，輸送機(jī)壯美效果隨之下降，回采巷道如果清理不徹底還會(huì)影響推移輸送機(jī)。所以圓環(huán)鏈的發(fā)展方向是提高抗拉強(qiáng)度和降低立環(huán)高度。3.1 材料及工藝為了提高圓環(huán)鏈的抗拉強(qiáng)度，目前國(guó)外 C 級(jí)和 D 級(jí)大規(guī)格圓環(huán)鏈在材料方面用 23MnNiCrMo54，23MnNiCrMo54 和 23MnNiCrMo64 精練鋼，拉伸強(qiáng)度極限 ≥1600～1800MPa。焊接工藝方面：采用先進(jìn)的堆焊設(shè)備，b?采用閃光堆焊和退貨加工工藝，成功地解決了堆焊過(guò)程中產(chǎn)生的過(guò)熱、過(guò)燒等問(wèn)題。在質(zhì)量檢測(cè)方面，對(duì)啦伸斷口利用掃描電纜進(jìn)行斷口分析；采用圓環(huán)鏈預(yù)拉伸強(qiáng)化工藝，極大提高了承載能力和疲勞強(qiáng)度。3.2 形式與幾何尺寸1985 年某公司率先制造出 38mm×137mm 扁平鏈。扁平鏈就是每根鏈條的平環(huán)仍然是圓環(huán)，而立環(huán)是被“擠壓”的扁平環(huán)。扁平鏈鏈環(huán)滑動(dòng)工作面積的增大降低了鏈條在槽體上的單位壓力，提高了立環(huán)的抗磨損性能；鏈條高度的降低使其更容易通過(guò)鏈輪，而且可以降低裝機(jī)功率和輸送機(jī)槽體高度?，F(xiàn)代高性能輸送機(jī)一般都涉及配套扁平鏈條。2003 年，某公司有研制處一種寬體扁平鏈，如圖 5 所示。它是一種高強(qiáng)度、低矮型鏈條，具有以下特點(diǎn)：圖 5 常規(guī)鏈條和新型寬體扁平鏈⑴采用這種鏈條可降低刮板鏈高度，從而降低中部槽高度，最終使用采高降低，滿足薄煤層開(kāi)采。⑵采用這種鏈條可以降低使用功率，或在功率不變的情況下，增大工作面的長(zhǎng)度，這將極大地減少開(kāi)拓工作量，減少工作面搬家次數(shù)。⑶這種鍛造的寬體扁平鏈加大了鏈環(huán)的接觸面積，可在提高鏈環(huán)強(qiáng)度的同時(shí)減少磨損，有助于保持鏈環(huán)的剛性。如 42mm 的扁平鏈可以承受 2×855kW 的裝機(jī)功率，而 50mm 寬體扁平鏈則可承受高達(dá) 3×1000kW的裝機(jī)功率。3.3 智能輸送機(jī)鏈由于無(wú)法準(zhǔn)確地預(yù)測(cè)鏈條的失效，按常規(guī)做法一般都是提早更換鏈條。2005 年某公司與多家科研院所合作，研究開(kāi)發(fā)一種輸送機(jī)鏈在線檢測(cè)系統(tǒng)。這是一種融合了集成傳感器技術(shù)的智能輸送機(jī)鏈，它能將鏈條的應(yīng)力特性實(shí)時(shí)記錄下來(lái)，借助微電子技術(shù)裝置，由計(jì)算機(jī)得出鏈條斷裂前的剩余使用壽命。另外還可以檢測(cè)鏈條的預(yù)緊力，有利于鏈條在使用壽命期內(nèi)達(dá)到到最佳使用狀態(tài)，提高安全性，避免意外事故。4　斷鏈故障處理方法(1) 斷上單鏈:發(fā)生上鏈單根斷鏈時(shí),首先清掉輸送機(jī)上堆煤,開(kāi)空倒車(chē)將斷鏈處開(kāi)到機(jī)尾附近,然后利用剎車(chē)器、阻鏈器(或單體支柱)等工具使鏈條有一定的裕量,用鏈接環(huán)將斷處連接;(2) 斷上雙鏈:發(fā)生上雙鏈斷鏈時(shí),首先清掉輸送機(jī)上堆煤,用材料道絞車(chē)鋼絲繩拴住下部鏈頭向機(jī)尾方向拉動(dòng),配合開(kāi)空倒車(chē)將斷鏈處開(kāi)到機(jī)尾附近,然后利用剎車(chē)器、阻鏈器(或單體支柱)等工具使鏈條有一定的裕量,用鏈接環(huán)將斷處連接,或用準(zhǔn)備好的相等長(zhǎng)度的鏈條將斷鏈更換;(3) 斷下雙鏈:發(fā)生下雙鏈斷鏈時(shí),首先清掉輸送機(jī)上堆煤,從估計(jì)斷鏈處打開(kāi)多個(gè)天窗尋找斷鏈位置;用材料道絞車(chē)鋼絲繩頭從機(jī)尾中板下部向機(jī)頭方向穿入,借助天窗,將繩頭一直送到斷鏈處,拴住下部鏈頭向機(jī)尾方向拉動(dòng);配合開(kāi)空正車(chē)將斷鏈處開(kāi)到機(jī)尾附近,再用導(dǎo)向滑輪將鏈頭牽到機(jī)尾中板上面過(guò)渡槽以下;再用絞車(chē)?yán)K頭將上面斷頭牽到機(jī)尾,然后利用剎車(chē)器、阻鏈器(或單體支柱)等工具使鏈條有一定的裕量,用鏈接環(huán)將斷處連接,或用準(zhǔn)備好的相等長(zhǎng)度的鏈條將斷鏈更換。5　斷鏈故障防范措施(1) 嚴(yán)格控制安裝質(zhì)量1) 安裝時(shí),應(yīng)點(diǎn)清元件數(shù)量,按安裝順序裝車(chē)運(yùn)輸,以防止元件不足時(shí)用舊件替代;2) 對(duì)工作面切眼底板進(jìn)行整理(特別是將廢舊金屬物清理干凈) ,確定機(jī)頭、機(jī)尾位置,同時(shí)應(yīng)預(yù)留機(jī)頭的安裝高度或進(jìn)行處理以滿足安裝高度,防止安裝位置錯(cuò)誤需要增補(bǔ)部件,或因卸載高度不夠損壞鏈條;3) 按設(shè)備要求進(jìn)行安裝,緊固刮板螺栓,對(duì)裝反的鏈條、刮板必須返工;4) 安裝過(guò)程中嚴(yán)禁頻繁點(diǎn)車(chē),避免元件、部件損壞。(2) 加強(qiáng)設(shè)備的維護(hù)管理1) 在設(shè)備運(yùn)行中,杜絕使用不合格的鏈條、鏈接環(huán);2) 要求推溜工嚴(yán)格推移步距和推移彎曲度;要求采煤機(jī)司機(jī)控制好頂?shù)装?以防出現(xiàn)臺(tái)階形底板,嚴(yán)防輸送機(jī)過(guò)負(fù)荷工作;3) 緊鏈時(shí)防止鏈條過(guò)松或過(guò)緊;4) 使用舊鏈條時(shí),須將等長(zhǎng)度的鏈條成對(duì)捆綁使用,如果無(wú)法找到同長(zhǎng)度鏈條時(shí),可將長(zhǎng)鏈從中斷開(kāi)成兩節(jié)捆綁使用,嚴(yán)禁不等長(zhǎng)度鏈條混用,嚴(yán)禁使用破斷強(qiáng)度不夠的鏈條;5) 實(shí)行定期定點(diǎn)檢修制,按要求定期更換機(jī)頭機(jī)尾鏈輪,以減少鏈輪和鏈條的磨損。(3) 提高職工技術(shù)素質(zhì),據(jù)多年來(lái)的使用經(jīng)驗(yàn),凡經(jīng)過(guò)培訓(xùn)后從事安裝工作的員工,工作效率高,返工率低,輸送機(jī)故障率也低。因此只有加強(qiáng)培訓(xùn),提高職工的技術(shù)素質(zhì),才能防止不正常故障的發(fā)生,減少不安全因素的發(fā)生,提高煤礦生產(chǎn)的經(jīng)濟(jì)效益。