Method of making a fire retardant conduit

DETAILED DESCRIPTION What is claimed is: 1.
A method for making a fire-retardant conduit comprising the steps of: providing a plurality of first cloth members made from carbon fibers and preimpregnated with a binder; applying each of the plurality of first members in sequence about a conduit wall to provide a first fire-retardant barrier portion; providing at least one of a second cloth member made from glass fibers and preimpregnated with a binder; applying the glass fiber member about the first member to provide a second fire-retardant barrier portion; applying a film of release material over the second portion; applying over the release film a shrinkable plastic material having the capability of contracting upon the application of heat; applying heat to the shrinkable material sufficient to cause it to contract and to press the first and second barrier portions toward the conduit wall and into contact with each other; and then curing the binder impregnated in the members.
2.
The method of claim 1 in which: the first and the second cloth members are woven cloth strips; and the cloth strips are applied by spiral wrapping of the strips, each strip in an alternating direction from the previous strip.
3.
The method of claim 1 in which: the first cloth members are knitted in the form of sleeves; and, the sleeves are applied by slipping, in sequence, each of the plurality of the sleeves about the conduit wall.




Description:
FIELD OF THE INVENTION This invention relates to fire-retardant barriers and, more particularly, to such a barrier for conduits capable of resisting metallic fires for example of the type created by burning titanium particles.
BACKGROUND OF THE INVENTION It has been recognized in the operation of such power-producing apparatus as gas turbine engines that friction between rotating and stationary cooperating members can generate metallic particles which can be accumulated or entrapped downstream of the point of friction.
Of particular interest has been titanium debris which can result from planned or occasional interference between compressor blades and opposed, cooperating portions of the compressor, rotating relative one to the other