Filling components

Abstract

A method of filling an internal cavity of a component for a machine with viscoelastic damping medium and/or insulating medium comprises pumping a plurality of capsules into the internal cavity using a peristaltic pump. Each capsule comprises a flexible skin encapsulating a viscoelastic damping medium, one or more viscoelastic damping medium precursors, an insulating medium, or one or more insulating medium precursors.

What is claimed is: 
     
         1 . A method of filling an internal cavity of a component for a machine with viscoelastic damping medium and/or insulating medium, the method comprising:
 pumping a plurality of capsules into the internal cavity using a peristaltic pump;   wherein each capsule comprises a flexible skin encapsulating a viscoelastic damping medium, one or more viscoelastic damping medium precursors, an insulating medium, or one or more insulating medium precursors.   
     
     
         2 . The method according to  claim 1 , wherein the plurality of capsules comprises at least two different types of capsule having differing contents. 
     
     
         3 . The method according to  claim 1 , wherein the plurality of capsules comprises capsules of at least two different sizes. 
     
     
         4 . The method according to  claim 1 , further comprising:
 directing placement of the capsules inside the internal cavity using a positioning aid.   
     
     
         5 . The method according to  claim 1 , wherein the plurality of capsules comprises low shear modulus capsules and high shear modulus capsules, the low shear modulus capsules having contents which (a) have a lower shear modulus than the contents of the high shear modulus capsules or (b) are curable to form a viscoelastic damping medium having a lower shear modulus than the viscoelastic damping medium formed on curing the contents of the high shear modulus capsules when subject to the same curing process, wherein the internal cavity comprises an inner region and an outer region, the outer region being adjacent an interior wall of the internal cavity and surrounding the inner region, and wherein the method comprises:
 arranging low shear modulus capsules in one of the inner region and the outer region; and   arranging high shear modulus capsules in the other of the inner region and the outer region.   
     
     
         6 . The method according to  claim 1 , wherein the plurality of capsules comprises capsules containing a plurality of stiffening elements dispersed in the viscoelastic damping medium, the one or more viscoelastic damping medium precursors, the insulating medium or the one or more insulating medium precursors. 
     
     
         7 . The method according to  claim 1 , further comprising:
 curing the viscoelastic damping medium, the one or more viscoelastic damping medium precursors, the insulating medium or the one or more insulating medium precursors in the internal cavity, for example, by applying heat and/or pressure to the component.   
     
     
         8 . The method according to  claim 1 , further comprising:
 heating the component, for example to about 60° C., during pumping of the plurality of capsules into the internal cavity.   
     
     
         9 . The method according to  claim 1 , further comprising:
 evacuating the internal cavity prior to or during pumping of the plurality of capsules into the internal cavity;   applying a gas back pressure on the plurality of capsules during pumping of the plurality of capsules into the internal cavity; and/or   pumping the plurality of capsules into the internal cavity together with a foaming agent.   
     
     
         10 . The method according to  claim 1 , wherein the component is a gas turbine engine component, for example, an aerofoil component such as a fan blade, compressor blade, turbine blade or guide vane for a gas turbine engine. 
     
     
         11 . A capsule for use in a method according to  claim 1 , the capsule comprising a flexible skin encapsulating a viscoelastic damping medium, one or more viscoelastic damping medium precursors, an insulating medium or one or more insulating medium precursors. 
     
     
         12 . The capsule according to  claim 11  further containing a plurality of stiffening elements dispersed in the viscoelastic damping medium, the one or more viscoelastic damping medium precursors, the insulating medium or the one or more insulating medium precursors. 
     
     
         13 . The capsule according to  claim 11 , wherein the viscoelastic damping medium or the one or more viscoelastic damping medium precursors comprise, or are curable to form, one or more thermosetting polymers, for example, one or more polyurethanes. 
     
     
         14 . The capsule according to  claim 11 , wherein the insulating medium or the one or more insulating medium precursors comprise an insulating mineral filler, for example, mineral powder or mineral fibres. 
     
     
         15 . The capsule according to any one of  claims 11 , wherein the flexible skin comprises a polymeric film, for example, comprising polyvinyl alcohol. 
     
     
         16 . An aerofoil component for a gas turbine engine, the aerofoil component comprising an external body having an internal cavity at least partially filled with a viscoelastic damping medium having a non-uniform spatial distribution of shear modulus. 
     
     
         17 . The aerofoil component according to  claim 16 , wherein the internal cavity comprises an inner region and an outer region, the outer region being adjacent an interior wall of the internal cavity and surrounding the inner region, and wherein the shear modulus of the viscoelastic damping medium is lower in the outer region than in the inner region. 
     
     
         18 . The aerofoil component according to  claim 17 , wherein the viscoelastic damping medium in the inner region comprises a plurality of stiffening elements. 
     
     
         19 . The aerofoil component according to  claim 16 , wherein the viscoelastic damping medium comprises one or more thermosetting polymers, for example, one or more polyurethanes. 
     
     
         20 . The aerofoil component according to  claim 16 , wherein the internal cavity is partially filled with an insulating medium in addition to the viscoelastic damping medium. 
     
     
         21 . The aerofoil component according to  claim 16 , wherein the aerofoil component is a fan blade, compressor blade, turbine blade or guide vane. 
     
     
         22 . A gas turbine engine comprising a plurality of aerofoil components according to  claim 16 .