# Furnace rigid felt liners

Carbon/graphite rigid felt liners, plates, and blocks for structural insulation in heat-treatment and vacuum furnaces.

Family: Thermal applications

## Description
**Rigid felt liners and panels** provide shape-stable insulation in heat-treatment furnaces and vacuum chambers. They are used as walls, roofs, disks, and low-conductivity structural elements.

They are often combined with **soft felt**: the rigid grade provides support and geometry; the soft grade fills gaps and improves the chamber’s thermal seal.

## Processes
- Structural insulation of furnace chambers
- Self-supporting liners and panels
- Die-cut or machined disks and parts

## Challenges
- Heat losses in large-area zones
- Need for shape-stable insulation
- Thermal shock during startups and shutdowns
- Panel installation with controlled clearances

## Advantages
- Greater stiffness and dimensional stability than soft felt
- Low thermal conductivity in vacuum
- Machinable plates, blocks, and geometries
- Combinable with soft felt liners

## Limitations
- Oxidation in air at high temperature
- Less flexible for irregular voids (complement with soft felt)
- Gasket and fastening design must account for shrinkage

- [Applications](https://esgraf.com/en/applications)
- [Alternate](https://esgraf.com/aplicaciones/hornos-liners-fieltro-rigido)