machines and apparatus for grinding, mixing, stirring, kneading, milling, crushing, drying, homogenising, dissolving, granulating and applying glue, mixing and grinding machines working under or above ambient pressure, ball mills and pebble mills, dispensing and homogensing mills, machines for mixing, drying, gelling and granulating of plastics, drying machines and plants, heating, mixing and stirring vessels, autoclaves; machines and apparatus for dissolving; parts and fittings therefore