(57) A rotary-type mill is provided with a valve assembly (16) in association with a loading
conduit (14) to enable the mill (11) to be charged under a controlled atmosphere so
used for materials, e.g. aluminium, that must be milled under an inert atmosphere.
To load material, a closed hopper (24) including a butterfly valve (25) is screwed
to the top of the conduit (14) to provide a gas-tight seal between them; during this
operation valve (16) is closed. The valve (16) is then opened by depressing valve
stem (20) and valve (25) is then opened to allow material to be milled to pass straight
into the mill (11). The valve (16) is then closed by pulling the stem (20) outwards
so that the valve plug (19) fits snugly into the mill wall (11), the hopper (24) is
removed and replaced by a fluid plate (not shown).
|
|
