CENTRIFUGAL SEPARATORS FOR SEPARATING DISCRETE PARTICLES FROM GASEOUS AND LIQUID FLUIDS; CENTRIFUGAL PARTICLE SEPARATORS FOR SEPARATING DISCRETE PARTICLES IN SUSPENSIONS; HYDROCYCLONE SEPARATORS FOR SEPARATING DISCRETE PARTICLES IN GASEOUS AND LIQUID FLUIDS; SCREENING DEVICES FOR SCREENING OUT DISCRETE PARTICLES IN GASEOUS AND LIQUID FLUIDS; AND PARTS OF THE AFORELISTED TYPES OF SEPARATORS AND SCREENING DEVICES