A calibration valve oil for hydraulic shield safety valves was formulated by a base oilobtalned from the distillate of a deep-refining paraffinic crude with qualified additives.
以深度精制的石蜡基馏分油为基础油，添加具有改善油品性能的添加剂研制了液压支架安全阀校阀油。
2
The United States VTON Granville shield imported pneumatic multi-stage step-down regulator valve, using the sleeve guide, pressure balanced valve.
美国VTON威盾进口气动多级式降压调节阀，采用套筒导向，压力平衡式阀芯。
3
A cut-off plane valve applicable for the hydraulic shield in the coal mine is introduced, which has the feature of high pressure, large flux and small handling moment.