| 摘要 |
The silencer contains one or more self-supporting sound absorbing components made of a porous ceramic with a compression strength of min. 40 kN/sq.m., and pref. min. 400 kN/sq.m. The ceramic has a specific resistance to air flow (SRA) of 10 power 3 to 10 power 7, pref. 10 power 4 to 10 power 6 Pa/sq.m. The pores in the ceramic are pref. interconnected and possess a dia. of 0.05-20 mm, esp. 0.5-5 mm. The ceramic components are pref. heat treated at min. 500 deg.C, and have a total porosity of 50-95%, esp. 70-90%, their density being 100-2500, esp. 200-1650 kg/cu.m. The ceramic is pref. cellular, the cells being formed by a foaming process using fermentation or stirring, or by bubbling a gas into the ceramic. The ceramic components are made by moulding and drying, and possibly sintering, so a self-supporting component is obtd. which is much more effective than loose fibres used in similar conventional silencers. |
