閥門的計劃維修

　　Planned maintenance of valves

　　閥門是設備和管道上的附件，它的維修應結(jié)合設備和管道的維修來進行。原燃料化學工業(yè)部規(guī)定的煉油廠設備維修檢修規(guī)程中規(guī)定，煉油廠公稱壓力低于PNl6MPa、介質(zhì)溫度低于550℃的油品、蒸汽、水及各類氣體的高、中、低壓閥門，其修理內(nèi)容分為小修、中修、大修三大類。各類包括的修理項目如下:小修：清洗油嘴、油杯，更換填料，清洗閥桿及其螺紋，清除閥內(nèi)雜物，緊固更換螺栓，配齊手輪等。中修：包括小修的項目，解體清洗零部件，閥體修補，研磨密封件，矯直閥桿等。大修：包括中修項目，更換閥桿，修理支架，更換彈簧與密封件等。在室內(nèi)修理的閥門，一般中、小修較普遍，但也應解體檢查和更換墊片。閥門的帶壓維修帶壓維修閥門是一項復雜、危險、技術性強的工作。帶壓維修閥門除應膽大心細、慎重果斷外，還應有嚴格的科學態(tài)度。特別是從事易爆、劇毒、高溫、高壓、放射性等介質(zhì)堵漏工作，更應嚴格按事先確定的方案及有關安全規(guī)定進行。帶壓維修閥門時，應注意如下事項:維修過程中，要嚴格遵守防火、防毒、防爆等有關安全操作規(guī)程。在處理帶壓閥門的缺陷前，應提出處理方案，取得安全技術人員的同意并得到操作工的配合。

　　Valves are accessories on equipment and pipelines, and their maintenance should be carried out in conjunction with the maintenance of equipment and pipelines. According to the maintenance and repair regulations for refinery equipment stipulated by the Ministry of Raw Material and Chemical Industry, the repair of high, medium, and low-pressure valves for oil products, steam, water, and various gases with a nominal pressure lower than PNl6MPa and a medium temperature lower than 550 ℃ in refineries is divided into three categories: minor repair, medium repair, and major repair. The various repair items include the following: minor repairs: cleaning the oil nozzle and oil cup, replacing the packing, cleaning the valve stem and its threads, removing debris from the valve, tightening and replacing bolts, and equipping the handwheel. Medium repair: including minor repair projects, disassembly and cleaning of components, valve body repair, grinding of seals, straightening of valve stems, etc. Major maintenance: including intermediate maintenance projects, replacing valve stems, repairing brackets, replacing springs and seals, etc. Valves repaired indoors are generally subjected to medium and minor repairs, but they should also be disassembled for inspection and replaced with gaskets. Pressure maintenance of valves is a complex, dangerous, and highly technical task. Valve maintenance under pressure should not only be bold, meticulous, cautious and decisive, but also have a strict scientific attitude. Especially when engaged in leak sealing work for explosive, highly toxic, high-temperature, high-pressure, radioactive and other media, it is necessary to strictly follow the predetermined plan and relevant safety regulations. When repairing valves under pressure, the following precautions should be taken: during the maintenance process, relevant safety operating procedures such as fire prevention, gas prevention, and explosion prevention should be strictly followed. Before dealing with defects in pressurized valves, a treatment plan should be proposed, approved by safety technicians, and cooperated with by operators.

　　重要部位的處理要經(jīng)過共同研究，按規(guī)定辦理火票、毒票等手續(xù)，方能著手處理閥門的缺陷。處理缺陷的工作應由實踐經(jīng)驗豐富的維修人員擔任，現(xiàn)場人員不宜過多并有1至2名專門的監(jiān)護人。應有周密的安全措施，以具備應付最壞情況發(fā)生的能力。維修人員及現(xiàn)場人員要按易燃易爆、高溫高壓、有毒、劇毒、強腐蝕等介質(zhì)的防護措施規(guī)定，穿戴好防護工作服、鞋帽、手套以及防護眼鏡。有毒、劇毒的閥門維修還應戴好防毒面具。在處理閥門缺陷過程中應設置安全擋板，同時應謹慎、細心，邊干邊觀察，按規(guī)定方案進行。擰緊螺紋前，應對銹死螺紋加煤油清洗滲透，檢查螺栓螺母是否完整；還應添加松銹液或一層石墨粉潤滑螺紋。擰緊螺母時，不能用力死擰，以防螺栓螺釘斷裂。焊接閥門時，要遵守焊接操作規(guī)程。應防止金屬過熱和變形，產(chǎn)生新的裂紋。對捻縫過的部位出現(xiàn)新的泄漏，不宜再次捻縫，以免擴大泄漏缺陷。

　　The treatment of important parts must undergo joint research, and procedures such as fire tickets and poison tickets must be handled according to regulations before starting to deal with valve defects. The work of handling defects should be undertaken by experienced maintenance personnel, and there should not be too many on-site personnel with 1 to 2 dedicated guardians. There should be thorough safety measures in place to have the ability to cope with the worst-case scenario. Maintenance personnel and on-site personnel should wear protective work clothes, shoes, hats, gloves, and protective goggles in accordance with the protective measures for flammable, explosive, high-temperature, high-pressure, toxic, highly toxic, and highly corrosive media. Toxic and highly toxic valves should also be repaired with a gas mask. During the process of handling valve defects, safety barriers should be installed, and caution and attention should be paid, observing while working, and following the prescribed plan. Before tightening the threads, clean and infiltrate the rusted threads with kerosene, and check whether the bolts and nuts are complete; Rust remover or a layer of graphite powder should also be added to lubricate the threads. When tightening the nut, do not apply excessive force to prevent the bolt and screw from breaking. When welding valves, it is necessary to follow the welding operation procedures. Metal overheating and deformation should be prevented from causing new cracks. If there is a new leakage in the area that has been sewn, it is not advisable to sew again to avoid expanding the leakage defect.

　　閥門的裝拆螺紋連接裝拆(1) 螺紋連接的防松方法閥門上常用螺母、彈簧墊圈、止動墊圈、開口銷等連接件來防止螺母松動。閥桿與關閉件連接結(jié)構(gòu)常采用止動墊圈卡緊法和帶翅墊圈卡緊法防松，效果較好。此外，閥門用來防松的方法有騎縫螺釘(騎馬螺釘)固定法和點鉚法，這兩種方法都用在不常拆卸的場合。點鉚法是將螺母與螺栓嚙合的螺紋處用洋沖點鉚兩點或兩點以上的位置，使螺紋處相互擠壓變形達到防松的目的。如果螺母松動用以上方法難以解決，可用粘接法。(2)左旋螺紋和右旋螺紋的識別正確識別螺紋是左旋還是右旋，是閥門裝拆的最基本的知識。那么，怎樣才能弄清螺紋是左旋還是右旋呢?可以借助該閥件上的內(nèi)螺紋或外螺紋來確定。一般情況下，它們成正反螺紋結(jié)構(gòu)，以防止螺紋松動。如閥桿、閥桿螺母上的螺紋連接：閥桿螺母上的緊圈為左旋，手輪上的螺紋為右旋，閥桿螺母的梯形螺紋為左旋。此外，螺紋的升角是向左邊升的螺紋叫左旋；反之為右旋。(3) ?拆裝螺栓的方法螺栓的拆卸和裝配方法通常與連接形式、損壞和銹死程度等因素有關。

　　Valve assembly and disassembly: Threaded connection assembly and disassembly (1) Anti loosening methods for threaded connections. Valve connectors such as nuts, spring washers, stop washers, and split pins are commonly used to prevent nut loosening. The connection structure between the valve stem and the closing element often adopts the locking method of the stop washer and the clamping method of the winged washer to prevent loosening, which has a good effect. In addition, the methods used to prevent loosening of valves include the saddle screw fixation method and the point riveting method, both of which are used in situations where disassembly is not common. The point riveting method is to use a punch to rivet two or more points on the threads where the nut and bolt are engaged, so that the threads are mutually compressed and deformed to achieve the purpose of preventing loosening. If the loosening of the nut cannot be solved by the above methods, the bonding method can be used. (2) The correct identification of left-hand and right-hand threads is the most basic knowledge for valve assembly and disassembly. So, how can we determine whether the thread is left-handed or right-handed? It can be determined by using the internal or external threads on the valve component. Generally, they form a positive and negative thread structure to prevent thread loosening. The threaded connection on the valve stem and valve stem nut: the tightening ring on the valve stem nut is left-handed, the thread on the handwheel is right-handed, and the trapezoidal thread on the valve stem nut is left-handed. In addition, threads with a rising angle to the left are called left-hand threads; Conversely, it is right-handed. (3) The method of disassembling and assembling bolts is usually related to factors such as connection form, damage, and degree of rust.

　　下面著重介紹雙頭螺栓的拆裝；銹死螺栓螺母的拆卸；斷頭螺栓的拆卸方法。① 雙頭螺栓的拆裝方法

　　The following focuses on the disassembly and assembly of double headed bolts; Dismantling of rusted bolts and nuts; The disassembly method of the broken bolt. ① Disassembly and assembly method of double headed bolts

　　雙螺母并緊一起的拆卸和裝配雙頭螺栓的方法。當要拆卸雙頭螺栓時，上扳手將上螺母擰緊 ?在下螺母上，下扳手用力將螺母反時針方向轉(zhuǎn)動， ?螺栓就會擰出。如果雙頭螺栓為反絲(左旋)的話，上扳手擰緊螺母，下扳手用力將螺母順時針方向擰出螺栓；當要把雙頭螺栓裝配到閥件上時，下扳手壓緊下螺母，上扳手順時針方向用力旋轉(zhuǎn)上螺母，就可將雙頭螺栓擰緊在閥體上。如果雙頭螺栓為反絲的話，下扳手壓緊下螺母，上扳手逆時針方向旋轉(zhuǎn)上螺母，就可擰緊雙頭螺栓。另一種擰緊雙頭螺栓的方法是用特制的螺帽，上面有一只螺釘，起并緊雙頭螺栓的作用，螺帽內(nèi)螺紋與雙頭螺栓同一規(guī)格。用時將雙頭螺栓旋入螺母中并緊螺釘，然后擰轉(zhuǎn)螺帽，就可擰轉(zhuǎn)雙頭螺栓。② 銹死螺栓螺母的拆卸方法銹死和腐蝕的螺栓和螺母拆卸前，應用煤油浸透，并弄清螺旋方向，然后慢慢地擰松1／4左右，退回原來位置；這樣反復進退幾次，就可逐漸擰出螺栓。也可用手錘敲擊螺栓及螺母四周，將螺紋振松，然后再擰松螺栓螺母(但在敲擊的過程中，不要敲壞螺紋)。用敲擊法難以拆卸的螺母，可用噴燈或氧炔焰加熱，使螺母受熱膨脹，迅速將螺母擰出。對難以拆卸的雙頭螺栓，用煤油浸透后，可用管子鉗卡在中間光桿位置上擰出。?③ 斷頭螺栓的拆卸方法螺栓折斷在螺孔中，是拆卸中感到麻煩的事。

　　The method of disassembling and assembling double headed bolts with double nuts tightened together. When disassembling the double headed bolt, tighten the upper nut onto the lower nut with an upper wrench, and turn the nut counterclockwise with force with the lower wrench to unscrew the bolt. If the double headed bolt is counterclockwise, tighten the nut with an upper wrench and use a lower wrench to force the nut clockwise to remove the bolt; When assembling the double headed bolt onto the valve component, the lower wrench should tighten the lower nut, and the upper wrench should rotate the upper nut clockwise to tighten the double headed bolt onto the valve body. If the double headed bolt is reverse threaded, tighten the lower nut with the lower wrench and rotate the upper nut counterclockwise with the upper wrench to tighten the double headed bolt. Another method of tightening a double headed bolt is to use a specially designed nut with a screw on top, which serves to tighten the double headed bolt. The internal thread of the nut is of the same specification as the double headed bolt. When using, screw the double headed bolt into the nut and tighten the screw, then turn the nut to turn the double headed bolt. ② The disassembly method for rusted and corroded bolts and nuts: Before disassembling rusted and corroded bolts and nuts, soak them in kerosene and clarify the direction of the spiral. Then slowly loosen about 1/4 and return them to their original position; Repeat this process a few times to gradually unscrew the bolt. You can also use a hand hammer to tap around the bolts and nuts to loosen the threads, and then loosen the bolts and nuts (but do not damage the threads during the tapping process). Nuts that are difficult to disassemble by tapping can be heated with a blowtorch or oxyacetylene flame to cause the nut to expand and quickly unscrew. For double headed bolts that are difficult to disassemble, after soaking them in kerosene, they can be clamped in the middle of the rod with a pipe clamp and screwed out. ③ The disassembly method of a broken bolt is troublesome when the bolt breaks in the screw hole.

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