# Furnace soft felt liners

Carbon/graphite soft felt liners and blankets for thermal insulation of heat-treatment, vacuum, and controlled-atmosphere furnaces.

Family: Thermal applications

## Description
**Soft felt liners** are the specific flexible-insulation application in heat-treatment furnaces (and vacuum or controlled-atmosphere chambers). The location is the furnace; the application is lining with soft felt blankets or sheets.

They are supplied in rolls or sheets, with cut-to-size options. Choice between **PAN** and **rayon** precursors, thickness, and number of layers depends on temperature, vacuum, purity, and chamber geometry.

## When to use it

- Lining chambers that need conformity to irregular shapes.
- Primary or secondary insulation layers alongside rigid panels.
- Partial replacements without redesigning the entire chamber.

## Processes
- Insulation of heat-treatment furnace chambers
- Lining of walls, roofs, and doors
- Multiple soft felt layers

## Challenges
- Heat losses and high energy consumption
- Poor fit to chamber geometry
- Fiber contamination on the load
- Difficulty replacing full rigid insulation

## Advantages
- Flexibility to fit curves and voids
- Low thermal conductivity
- Vacuum stability up to elevated temperatures (grade-dependent)
- Cut-to-size from rolls and sheets
- PAN and rayon grades by purity and process

## Limitations
- Oxidation in air above ~400–500 °C
- Lower structural capacity than rigid felt
- Requires fastening or extra layers in load zones
- PAN vs rayon selection must be validated for contamination and vacuum

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