Abstract: A fluid distributor/collector assembly is composed of a screen cylinder, a perforated tube provided in the screen cylinder and support discs also provided in the screen cylinder. The screen cylinder is made of cylindrically arranged support rods and a wire screen wound helically on the support rods. The perforated tube is formed with apertures for distributing or collecting fluid which flows through the wire screen. The support discs radially support the screen cylinder outwardly from the perforated tube thereby defining a space between the screen cylinder and the perforated tube. Within each support disc is an opening in which the perforated tube is supported. The assembly can be buried in a catalyst bed within a catalytic reactor and used to distribute or collect fluid.