Pneumatic valve forced sealing, since the tight closure

since the tight sealing principle, in accordance with the sealing principle of sealing can be divided into two categories, namely forced sealing and the tight closure. ( Pneumatic valve forced sealing tight in the flange bolts, impose pressure on sealing gaskets, gasket of preloaded by compression, seal surface uneven micro gap has been filled. This prevents medium leakage, formed the initial seal condition, form a preloaded pressure seal face. When the medium pressure rise and the operation of pneumatic valves, preloaded pressure drop on the surface of the seal, gasket springback. If the gasket have enough resilience ability, make the sealing work on the surface of the sealing pressure is always greater than medium and operating pressure, keep good seal, seal face. Visible, the necessary condition of forced sealing is under medium grateful and operating force, seal surface can still maintain the residual compression force. Should be emphasized is that strong sealing system, medium pressure always tends to decrease pre tight sealing pressure reducing sealing performance. Typical of mandatory seal structure is flat gasket seal, winding gasket seal and tooth gasket seal, etc. Is typically used for low pressure, medium and small and medium caliber of pneumatic valve. ( Before pneumatic valve since the tightly sealed booster, tighten bolts, pneumatic valve cover up, make the pneumatic valve cover and wedge between gasket, and pneumatic initial seal conditions formed between the body and wedge gasket - preloaded pressure on the surface of the seal. When the medium pressure rises, pneumatic valve cover by medium pressure, moving up, pneumatic valve cover and wedge gasket, and pneumatic between the body and wedge gasket sealing pressure ratio, with the increase of the pressure gradually increase. In the tight seal, seal work on the surface of the seal pressure synthesis consists of two parts: one is tightly sealed pressure, 2 it is formed by medium pressure pressure. Should be emphasized: the tightly sealed, medium pressure tend to increase the tight sealing pressure, increase the sealing performance. Sealing medium pressure, the higher the work pressure is big, the more sealing performance. According to this characteristic, since the tight seal as high-pressure sealing technology, commonly used in high temperature and high pressure, large diameter pneumatic valve adjustment. Since the tight seal according to the medium pressure in sealing mat in the direction of the force, and can be divided into axial since the tight sealing and radial since tight closure. Axial since the tight sealing wedge or seal ( Wood seal and seal wedge, flat mat since the tight sealing, C ring seal and the o-ring seal. Radial since the tight seal with double cone seal and seal ring B, triangle gasket seal, octagonal ring ( Oval ring sealing and lens gasket sealing.