高壓液壓閥密封技術(shù)和分析

 

    液壓閥是用來控制液壓系統(tǒng)中油液的壓力、流量和液體流動方向，是一種用壓力油操作的自動化元件，它受配壓閥壓力油的控制，通常與電磁配壓閥組合使用，液壓支架是采煤機械中的支護設(shè)備，經(jīng)過大修在井下一般可使用5年，但是液壓支架各種液壓閥的使用壽命卻是很低，長的3個月，短的只有幾個星期。

    進過測試工作液中含有雜質(zhì)是密封元件損壞的原因。雜質(zhì)在密封元件之間有摩擦造成了閥的泄漏。國外曾經(jīng)想通過相應(yīng)等級的液壓元件相應(yīng)精度的過濾器。他們認為5μM的油泵密封元件，如果采用過濾精度為3／μM的過濾器，壽命可比采用10μM的提高10倍。

    隨著液壓支架技術(shù)的發(fā)展，對閥的使用性能和閥的使用壽命提出了更高的要求，但是液壓支架用閥，工作環(huán)境十分惡劣。密封元件損壞的主要因素是工作液中的雜質(zhì)，這些雜質(zhì)在密封元件間研磨，使閥產(chǎn)生泄漏。在采煤工作面，油管總長1000多米，接頭插口多達4000多個，液箱無特殊的防塵設(shè)施。乳化液中有大量的漂浮雜質(zhì)，在立柱缸底和閥腔，留有較多的煤粉、巖粒和鐵屑。進液閥芯和閥座，由于開啟關(guān)閉比較頻繁，液體流速高，密封很快就會失效。實踐證明減少支架液壓系統(tǒng)液體的污染雜質(zhì)，是十分困難的，有人曾經(jīng)設(shè)想在乳化液泵站采用高壓過濾器，同時在每臺支架進口處增加小型過濾器。但在工作中很快被堵塞，形成斷流。

    目前另一方面，在裝有120目時的過濾器和磁過濾裝置的條件下，用通過被測試閥的乳化液的總流量和閥的啟閉次數(shù)，來計量閥的壽命。但實際上室內(nèi)型式試驗與井下實際工作結(jié)果相差很大。 為此，需要使用新型的、抗污染能力強的、適合于井下工作條件的密封副。

    液壓閥密封材料的歷史及現(xiàn)狀閥芯和閥座接觸面的泄漏，是工作液體分子擠入的結(jié)果。影響密封效果的主要原因是閥芯和閥座的接觸比壓、不平度及壓差。當閥芯與閥座的接合面以P力壓緊，工作液體分子以F力擠入，密封材料會產(chǎn)生彈性變形。如果密封副總抗力大于分子斥力，則密封有效，否則就會形成泄漏。 早期的液壓支架，運動副之間沒有其他密封措施，是金屬直接接觸密封，即要求密封副接觸平面吻合，具有較高的加工精度，否則必須加大密封副的結(jié)合力，使接觸表面產(chǎn)生塑性變形，堵塞泄漏通道。

Hydraulic valve is used to control the hydraulic system pressure, flow and liquid flow direction, is a kind of pressure oil operations automation components, it is controlled by the pressure valve of the oil pressure, usually associated with electromagnetic pressure valve, hydraulic support is support in the coal mining machinery equipment, after a general overhaul in the underground can be used for 5 years, but the service life of hydraulic valve hydraulic support is very low, 3 months long, only a few short weeks.

 

 

 

In the tested liquid containing impurities is causes damage to seal components of. Impurities are caused by friction between the valve leakage at the sealing element. Foreign thought through the corresponding hydraulic components of the corresponding grade filter precision. They think the sealing element pump with 5 μ M, if the filtering accuracy of 3 / μ M filter, life can be more than 10 times higher in 10 μ

 

 

 

With the development of the hydraulic support technology, put forward higher requirements for the use of valve performance and valve life, but the hydraulic valve, the working environment is very bad. Main factors that damage the sealing elements is the working fluid impurities, these impurities in the ground between the sealing elements, so that the valve leakage. In the coal face, tubing length of 1000 meters, up to more than 4000 joint socket, the tank without a special dust-proof facilities. A large number of floating impurities in the emulsion, and the valve chamber in the column bottom, left more coal, rock and iron tablets. Inlet valve and seat, due to open and close more frequently, the liquid flow rate is high, sealing will soon expire. Practice has proved that reduction of pollution of hydraulic system fluid impurities, is very difficult, it was envisaged in the emulsion using high-pressure pump filter, while a small increase in the entrance of each stent filter. But was quickly blocked at work, the formation of drying.

 

 

At present, on the other hand, with the filter and magnetic filtration device 120 mesh under the condition of opening and closing times, with the total flow rate and the valve of the emulsion of the test valve, to measure the valve's life. But in fact the underground room type test and the actual results vary greatly. Therefore, need to use new sealing, anti pollution and strong, suitable for underground working conditions.

 

 

Hydraulic valve seal valve core and valve seat contact surface of the history and current situation of material leakage, work the liquid molecules is the squeeze. Affect the sealing effect is mainly due to valve and seat contact pressure ratio, roughness and pressure. When the valve core and valve seat of the joints in P pressed force, work force F squeeze the liquid molecules, sealing materials will produce elastic deformation. If the seal resistance greater than the vice president of molecular repulsion, then sealed and effective, otherwise it will form a leak. Early hydraulic support, no other seal between the motion pairs measure, direct contact with the metal seal, which called for sealing contact plane anastomosis, with a high machining accuracy, or to increase the binding force of sealing, the contact surface of the plastic deformation, plug the leak channel.