In casting installation, vibration is only allowed for which types of casting?

Vibration is primarily utilized in the context of pump and cast installations to ensure the proper consolidation and placement of the refractory material. This method helps to eliminate air pockets and voids that may form during the casting process, thereby enhancing the overall density and integrity of the installation. The use of vibration assists in achieving a uniform distribution of the refractory material, leading to improved performance and longevity of the refractory lining.

In contrast, the other options involve methods of installation that either do not require or are not compatible with vibration techniques. For instance, spray applications generally rely on the kinetic energy of the spray to distribute the material effectively without the need for additional vibration. Manual installations typically involve placing material by hand, where vibration may not be practical or necessary. Dry and wet installations refer to the consistency of the mixture used but do not inherently incorporate vibration as a technique in their application. Thus, the unique characteristics of pump and cast installations make them the only type where vibration is both allowed and beneficial.