Evacuated diving suit insulation

Abstract

An insulating material suitable for use in a diver's garment or garment-like apparatus. The insulating material comprises a multiplicity of layers of a flexible, stretchable material. These layers include a central core consisting of a gas permeable, preferably multicomponent, layer of a material that is substantially non-compressible when at least partially evacuated and subject to hydrostatic pressure when immersed in water. Two further and gas impermeable layers are provided, each of these further two layers being of a stretchable material with the central core being disposed intermediate to said layers. When formed into a diver's garment, the peripheral edges of the insulating material are sealed, and sealable closure means are provided in at least one of the gas impermeable layers to communicate with the central core. This closure means is conveniently in the form, for example, of a valve and valve stem arrangement, whereby the central core can selectively be placed under superatmospheric or sub-atmospheric pressure. The gas permeable core preferably comprises a multiplicity of lamina of a knitted fabric stretchable in two directions such as hosiery material of nylon or perlon and may be impregnated by particulate matter.