原文：
            农业机械的液压系统中，压力阀是应用较多的一类元件，压力阀突然失效会直接影响机械设备的正常运行，本文分了压力阀的失效原因并举例介绍了压力阀的测试方法。

       1.失效的常见原因

（1）液压阀芯和阀体在使用时不断产生磨损，使 得零件尺寸、形状和表面质量发生变化。

 （2）液压阀中的平衡弹簧、阀芯及阀座截止阀，在长期变载荷下工作，产生疲劳及裂纹，造成弹簧、折断或阀座密封表面剥落、损坏。

 （3）液压阀零件加工过程中残留的残余应力和使用过程中的外载荷应力，超过零件材料的屈服强度，零件产生变形。

 （4）液压油中混有水分或酸性物质过多，使用较长时间后，腐蚀液压阀中的零件，使其丧失应有的精度。

 （5）阀芯与阀套间液的径向力不平衡，安全阀最终使阀芯压向阀套内壁面出现卡紧现象。

 （6）在液压阀制造或修理时，没有达到规定的技术要求;或零件保管不善，发生锈蚀，混入污物等。

       2.测试方法举例 压力阀包括溢流阀、减压阀和顺序阀等，本文以溢流阀为例说明压力阀 针型阀(针阀)的测试项目和测试方法。压力阀的测试可以在专用的试验台上进行，也可以在综合性试验台上进行。

 （1）调压范围及压力稳定性测试。调节被试阀的调节手轮，从全开至全闭，再至全开，从压力表看出压力上升与下降情况以及调压范围。压力表指针应平稳上升与下降，调压范围应满足规定的调压范围，在最高压力时，减压阀 压力脉动值不得超过规定值。

\ （2）内泄漏量的测试。调节被阀的调节手轮至全闭位置，调节溢流安全阀为被试阀的最高压力，然后调节试阀的调节手轮，使被试阀溢流口测量内泄漏量。

 （3）卸荷压力测试。将溢流阀的远程控制口接油箱仪表阀门，使被试阀通过检验流量，测量溢流阀的进出油口压力，其差值即为被试阀的卸荷压力。

 （4）压力损失测试。调节被试阀的调节手轮至完全松开，并使被试阀通过检验流量，由压力表测量溢流阀的进出油口压力，其差值即为被试阀的压力损失。]

 （5）启闭特性测试。关闭溢流安全阀，调节被试阀至最高压力，调节溢流安全阀使系统逐渐降压，当降至被试阀的闭合压力时测量被试阀的溢流量。调节溢流安全阀，从被试阀不溢流开始，使系统逐渐升压，当升至被试阀的开启压力时，测量被阀的溢流量。

“ Agricultural Machinery Failure pressure valve and test methods ”是由中国止回阀网提供的阀门新闻，译文仅供参考。另外，中国止回阀网还提供相关产品搜索： 旋启式止回阀、 升降式止回阀、 对夹式止回阀、 消声止回阀、 微阻缓闭止回阀等。

译文：
       Agricultural machinery hydraulic system, the pressure valve is to apply more of a class of devices, pressure valves sudden failure will directly affect the normal operation of machinery and equipment, the paper points the pressure valve failure reasons and examples of the Safety valves pressure valve of the test method. 1. A common cause of failure (1) hydraulic valve spool and the continuous generation of wear in use, making part size, shape and surface quality changes. (2) the balance of hydraulic valve springs, valve and seat, long-term changes in work load, fatigue and cracks, resulting in spring, break, or seat sealing surface spalling, damage. (3) hydraulic valve parts during the processing of residual stress and residual use during the load stress, Mud Valvesover parts of the material yield strength, deformation parts. (4) hydraulic oil mixed with water or too much acid, using a longer time, corrosion of hydraulic valve parts, due to the loss of accuracy. (5) solution suite spool and valve radial force imbalance, ultimately spool valve comprising a wall pressure appears to clamping phenomenon. (6) in the manufacture or repair of hydraulic valves, did not meet technical requirements; or parts to improper care, occurrence of corrosion, dirt and so mixed. 2. Testing example Pressure valves including relief valves, Balance valves pressure reducing valve and the sequence valve, relief valve as an example to explain this pressure valve test items and test methods. Pressure valve can be tested at a dedicated test bench, can also be integrated test bench. (1) the scope and the pressure regulator stability test. Regulating valve to be tested hand wheel adjustment, from fully open to fully closed, and then to fully open from the pressure gauge shows the pressure rise and fall as well as voltage regulation range. Pressure gauge pointer should be a smooth rise and fall, surge of reference should meet the requirements of the regulating range, the maximum pressure, pressure fluctuation value may not exceed the specified value. (2) within the leakage test. Gauge ValvesRegulating valve adjustment by hand wheel to the fully closed position to regulate run-off safety valve to be tested for the maximum pressure valve, and then try adjusting the valve hand wheel adjustment, so I measured the subjects within the overflow valve leakage. (3) unloading stress testing. The relief valve of the tank remote control port connected to test flow through the valve was tested to measure the pressure relief valve in and out of the oil port, the difference shall be pressure unloading pilot valve. (4) pressure loss test. Regulating valve to be tested to fully release the hand wheel adjustment, and to be tested by examining the flow valve, relief valve by the pressure gauge measuring the pressure out of the oil port, the difference shall be pilot valve pressure loss. (5) opening and closing characteristics tests. Close the overflow valve, regulating valve was tested to the highest Globe Valvespressure, regulate blood pressure overflow valve make the system gradually, when the pilot valve closed down to be measured by test pressure overflow valve flow. Adjust overflow safety valve, pilot valve does not overflow from the beginning was to make the system gradually step-up, rose to be tested when the valve opening pressure, measured by the excess flow valve.

原文来源：http://www.1zhihuifa.com/

2010-08-25 07:19

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