Saveguard Vehicle Exhaust Insulation Products
Acousta-fil Acoustic Insulation

Introduction

Acousta-fil should be considered as a convenient and cost effective method of delivering acoustic insulation materials into automotive exhaust silencers. The unique method of manufacture allows us to use a variety of fibres and filament diameters including high temperature resistant Glass and Silica. The fibres can be as continuous filament yarns and rovings and also in mixed filament diameter or tex. Our acoustic testing shows that by varying filament and yarn diameters or by using mixed diameters we can achieve a pack with optimum absorption over a particular frequency range.

Construction:

 Acousta-fil is a soft flexible textile and is easy to handle and install with minimal irritation due to the style of yarns used in manufacture. Acousta-fil is manufactured from voluminised yarns. Voluminisation is achieved by passing the yarns over high pressure air jets opening the filaments and increasing the thickness and the volume of the yarn. These yarns are then assembled depending on the desired weight and density required and then tightly compressed by means of a fine low temperature melting thread within the final knitting process. Acousta-fil will expand on initial heating, the catch threads soften and then melt at temperatures (below 130C as standard, 80C for the optional low melt version) the fibres are then released to fill the silencer chamber.

The density of Acousta-fil can be altered in line with the final silencer fill density by increasing the number of courses and catch threads used in manufacture. The unexpanded Acousta-fil Initial density can be varied from 150 Kg/m3 to + 650 Kg/m3 to give different rates of expansion and to minimise any excess noise occurring before the material expands in the silencer.


Installation:

Acousta-fil is therefore very versatile and can be used in place of pre-forms or "bags" of blown roving in clamshell designs or where the silencer has complicated internal tube arrangements as in the sketch below.

The Acousta-fil fabric can be wrapped around the perforated tubes or inserted as pre-rolled packs into the cavities.

Some clamshell arrangements may require a profiled version of Acousta-fil fabric that has been knitted to the shape of the can and repeated down the length as shown fig. 3. This is the latest development of the product and is made on purpose built machinery. Almost any shaped profile is possible and when folded into layers see fig.4 it is possible to create a three dimensional pack supplied ready to insert into the silencer.