高压液压阀密封技术和分析

高压液压阀密封技术和分析

 

    液压阀是用来控制液压系统中油液的压力、流量和液体流动方向，是一种用压力油操作的自动化元件，它受配压阀压力油的控制，通常与电磁配压阀组合使用，液压支架是采煤机械中的支护设备，经过大修在井下一般可使用5年，但是液压支架各种液压阀的使用寿命却是很低，长的3个月，短的只有几个星期。

    进过测试工作液中含有杂质是密封元件损坏的原因。杂质在密封元件之间有摩擦造成了阀的泄漏。国外曾经想通过相应等级的液压元件相应精度的过滤器。他们认为5μM的油泵密封元件，如果采用过滤精度为3／μM的过滤器，寿命可比采用10μM的提高10倍。

    随着液压支架技术的发展，对阀的使用性能和阀的使用寿命提出了更高的要求，但是液压支架用阀，工作环境十分恶劣。密封元件损坏的主要因素是工作液中的杂质，这些杂质在密封元件间研磨，使阀产生泄漏。在采煤工作面，油管总长1000多米，接头插口多达4000多个，液箱无特殊的防尘设施。乳化液中有大量的漂浮杂质，在立柱缸底和阀腔，留有较多的煤粉、岩粒和铁屑。进液阀芯和阀座，由于开启关闭比较频繁，液体流速高，密封很快就会失效。实践证明减少支架液压系统液体的污染杂质，是十分困难的，有人曾经设想在乳化液泵站采用高压过滤器，同时在每台支架进口处增加小型过滤器。但在工作中很快被堵塞，形成断流。

    目前另一方面，在装有120目时的过滤器和磁过滤装置的条件下，用通过被测试阀的乳化液的总流量和阀的启闭次数，来计量阀的寿命。但实际上室内型式试验与井下实际工作结果相差很大。 为此，需要使用新型的、抗污染能力强的、适合于井下工作条件的密封副。

    液压阀密封材料的历史及现状阀芯和阀座接触面的泄漏，是工作液体分子挤入的结果。影响密封效果的主要原因是阀芯和阀座的接触比压、不平度及压差。当阀芯与阀座的接合面以P力压紧，工作液体分子以F力挤入，密封材料会产生弹性变形。如果密封副总抗力大于分子斥力，则密封有效，否则就会形成泄漏。 早期的液压支架，运动副之间没有其他密封措施，是金属直接接触密封，即要求密封副接触平面吻合，具有较高的加工精度，否则必须加大密封副的结合力，使接触表面产生塑性变形，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.