DENSITOMETERS; ELECTROPHORETIC SEPARATORS AND ANALYSIS INSTRUMENTS; MICROSCOPES; PARTICLE MEASURING AND COUNTING INSTRUMENTS; CONCENTRATORS OF PARTICULATE MATTER; CONTAMINATION MONITORING INSTRUMENTS; EQUIPMENT EMPLOYING FILTERS FOR FILTERING, ANALYZING, SAMPLING, MONITORING AND SEPARATING CONSTITUENTS IN FLUIDS; AND EQUIPMENT EMPLOYING FILTERS FOR STERILIZING, CLEANING, AND CONTROLLING FLUIDS

FILTERING APPARATUS-NAMELY, FILTERS, PREFILTERS, CARTRIDGE FILTERS AND ULTRAFILTRATION MEMBRANES