免费观看成人欧美www色-免费观看成人毛片a片-免费观看激色视频网站-免费观看美女裸体网站-免费观看羞羞视频网站-免费观看黄网站

It is necessary to improve the anti-corrosion and anti fouling capabilities of valves

  • 4676 Views
  • 2014-10-07
At present, the injection one-way valve of the three purpose valve for single hydraulic props in China has been equipped with a ball valve structure for many years. In underground use, it is easy to accumulate coal powder in the injection hole of the one-way valve seat, which is carried into the single hydraulic props during injection. At the same time, the concentricity of the ball valve core is poor, and during liquid injection, the position of the ball will rotate, causing coal dust to be trapped on the sealing surface, leading to slow leakage. The unloading valve adopts a flat convex structure sealing type, resulting in a lower strength of the left valve barrel of the three purpose valve. After the valve barrel is corroded, repairing the convex will weaken the strength of the valve barrel. The safety valve has a small flow rate and poor adaptability to the top plate.

In foreign countries, research and improvement on the three purpose valve for single hydraulic props have been relatively rapid. For example, the new generation of single hydraulic prop three way valves produced by German company Danmas have made significant improvements in both performance and structure. In October 1993, Danmas demonstrated its newly developed three way valve, which uses a new anti-corrosion material treatment process for its valve shell, stainless steel material for its valve core, valve seat, and spring, which has good anti-corrosion ability. Its structure adopts a large flow safety valve structure. The safety valve spring adopts a gas spring, which reduces the spring stiffness and improves the performance of the safety valve. The air chamber adopts an adjustable structure and has excellent performance. All of its seals adopt new polyurethane seals, greatly improving their service life. The performance parameters are shown in the table. Therefore, it is necessary to develop a new type of anti-corrosion and anti pollution three-way valve to improve the service life of single hydraulic props and three-way valves in China, and to enhance the anti-corrosion and anti pollution capabilities of the valve.
主站蜘蛛池模板: 我和亲妺妺乱的性视频| 日韩黄色网页| 日本中文字幕视频| 福利免费在线| 久久综合亚洲色一区二区三区| 色婷婷综合久久久久中文一区二区| 天天射天天怕| 亚洲伊人成无码综合网| 成熟了的熟妇毛茸茸| 欧美一区二区在线播放| 波多野结衣xxxx性精品| 精品久久久久久亚洲中文字幕| 欧美日韩一级视频| 99精品99| 午夜免费男女aaaa片| 国产欧美性综合视频性刺激| 一区二区视屏| 亚洲小说少妇区图片| 亚洲欧美一区二区三区情侣bbw| 欧美日韩一区二区三区视频播| 亚洲字幕av一区二区三区四区| 草草浮力地址线路①屁屁影院| 天天摸日日碰天天看免费| 中文字幕丰满伦子无码| 成人网站在线进入爽爽爽| 国产毛片视频| 日产精品久久久久久久蜜臀| 国产精品极品美女自在线看免费一区二区| 亚洲国产第一区二区香蕉| 少妇被多人c夜夜爽爽| 亚洲网视频| 亚洲九九香蕉| 欧美人与动欧交视频| 综合九九| 久久777国产线看观看精品| 精品久久久无码中文字幕| 日韩在线成人| 亚洲熟妇无码另类久久久| 操操操操网| 欧美日韩一区二区综合在线视频| 国产性生交xxxxx免费|