| 摘要 |
<p>The safety valve is placed in a branch mounted on the tank filling pipe, which is normally sealed by a cap. A membrance, made from a natural or synthetic elastomeric material which is resistant to hydrocarbons is placed between the edges of two concentric cylindrical elements made from moulded polypropylene. The membrane is about 0.5 mm thick and is mounted in the elements to allow an axial play of 0.5 to 1.0 mm and a radial play of 0.3 to 0.4 mm. Slits are provided in the membrane which allow a flow of gas in either direction under pressure, through the membrane.</p> |
