In high-temperature piping systems within industries such as petrochemicals and metallurgy, heat loss prevention and surface high-temperature protection for valves (operating temperatures often reaching 300°C–1200°C) are critical requirements. Ceramic fiber wool, with its low thermal conductivity, high-temperature resistance, and excellent flexibility, serves as the ideal filling material for high-temperature valve insulation structures. Scientifically designing ceramic fiber wool-filled insulation structures effectively reduces valve heat loss and ensures safe equipment operation. Key design considerations are outlined below.
Layered filling design is central to enhancing insulation performance. Based on the temperature rating and structural characteristics of high-temperature valves, a “multi-layer ceramic fiber wool gradient filling” approach should be adopted: For medium-temperature valves (300°C-600°C), the inner layer uses standard ceramic fiber cotton with a density of 128 kg/m³ (50 mm thick), overlaid by a layer of high-alumina ceramic fiber cotton with a density of 160 kg/m³ (30 mm thick). This leverages the superior high-temperature stability of high-alumina ceramic fiber cotton to reinforce insulation. For high-temperature valves (600°C-1200°C), an innermost layer of zirconia-containing ceramic fiber cotton (density 192 kg/m³, thickness 40 mm) is added. This zirconia-containing ceramic fiber cotton withstands temperatures exceeding 1600°C, effectively blocking high-temperature radiation and conduction. During layered filling, adjacent layers of ceramic fiber cotton must be staggered with joints offset by no more than 5mm to prevent continuous thermal pathways and ensure overall insulation continuity.

Sealing and leak prevention design are critical to maintaining thermal integrity. Areas prone to insulation gaps include valve body-to-pipeline connections and moving valve stem sections. Targeted ceramic fiber cotton sealing structures are required: – At valve body-to-pipeline junctions, pre-formed ceramic fiber cotton sealing rings (20mm thick) are wrapped around the connection. The inner surface of the sealing ring is coated with high-temperature adhesive (temperature resistance ≥1000°C) to ensure tight adhesion to the valve body. For the valve stem area, a “flexible ceramic fiber cotton seal sleeve” is designed. Made from highly elastic ceramic fiber cotton (elastic recovery rate ≥85%), this expandable sleeve fits over the valve stem exterior. It allows unrestricted valve stem rotation while preventing heat leakage through stem gaps. After implementing this sealing design, a petrochemical enterprise reduced high-temperature valve heat loss from 18% to 6%, while lowering the valve body’s external surface temperature from over 200°C to below 60°C. ​
The fixation and protective structure design must balance stability and maintainability. After filling with ceramic fiber cotton, it is secured by an outer protective shell. The shell uses 0.5mm thick stainless steel plate (or color-coated steel plate) with a “split-half” structure for easy disassembly during valve maintenance. For fixation, stainless steel support ribs spaced at 200mm intervals are welded to the inner surface of the protective shell. The ceramic fiber wool is layered and secured between these ribs to prevent displacement due to vibration or temperature fluctuations. Additionally, at the connection between the protective shell and the valve flange, ceramic fiber cotton woven tape is wrapped for sealing, then secured with stainless steel clamps (spaced 150mm apart) to prevent the ceramic fiber cotton from being exposed or falling out at the joint.
Customized design for irregular sections is crucial for adapting to complex valve structures. For irregular components like high-temperature valve plugs and bonnets, employ a combined approach of “custom-made ceramic fiber cotton prefabricated parts + on-site filling”: and assembled directly on-site for filling. For confined spaces like valve bonnet grooves, use loose ceramic fiber cotton (fiber length ≥50mm), compacted with specialized tools (compaction density ≥150kg/m³) to eliminate voids and achieve comprehensive thermal coverage.
Additionally, design considerations must address long-term stability of the ceramic fiber cotton: Select high-temperature cured ceramic fiber cotton (thermal shrinkage rate ≤1%/1000℃×24h) to prevent dimensional shrinkage gaps under prolonged high temperatures. Simultaneously, incorporate temperature monitoring ports in the protective shell to facilitate periodic valve surface temperature checks, enabling timely detection of ceramic fiber cotton aging or filling defects to ensure sustained insulation effectiveness. Through these design measures, the ceramic fiber wool-filled high-temperature valve insulation structure achieves a heat loss rate ≤5% and surface temperature ≤60°C, providing reliable assurance for energy efficiency and safe operation of high-temperature valves.