| 摘要 |
<p>The system includes a downstick , and several horizontal runner arms located round the bottom end of the downstick . Both the downstick and arms consist of a coaxial row of tubes surrounded by a sheath. The sheath pref. consists of (a) a sheet made of fibrous refractory; or (b) a refractory; which is moulded round the tubes and contains a binder, or is hardened by CO2. Refractory (b) pref. contains a hardening agent and a foamant so it forms a foamed sheath round the tubes, which pref. consists of a pre-baked refractory. In the past, the downstick has been assembled using a coaxial row of tubes in a sheath made of cast iron, which is heavy and expensive. The invention eliminates the cast iron sheath.</p> |
