System for dosing fluid

An apparatus for use in dosing a stream of fluid with at least one active substance from a block containing the active substance, the apparatus comprising:

• a housing which defines a chamber having an inlet and an outlet to enable fluid to flow through the chamber;
• and
• a holding assembly for holding the block in an operative position within the chamber between the inlet and the outlet;
• and
• a fluid flow distributor to distribute the fluid entering the chamber through the chamber's inlet to flow over the inner and outer surfaces of the block, wherein the fluid flow distributor comprises a plate having an inner set of apertures for directing fluid to flow over the inner surface of the block and an outer set of apertures for directing fluid to flow over the outer surface of the block.

A system for dosing a stream of fluid with at least one active substance, the system comprising:

• a housing which defines a chamber having an inlet and an outlet to enable the flow of fluid through the chamber;
• a block containing the at least one active substance, the block comprising a body having an outer surface and a passage therethrough defining an inner surface, and wherein the block is positioned within the housing chamber in an operative position between the inlet and the outlet so that in use fluid flows over the inner and outer surfaces of the block to dissolve and/or erode the block;
• and
• a holding assembly for holding the block in its operative position within the chamber between the inlet and the outlet, the holding assembly comprising:
• a first plate and a second plate and wherein the block is held between the plates in its operative position;
• and
• one or more positioning members for positioning the block in its operative position within the chamber, wherein the positioning member(s) comprise at least two rods extending longitudinally within the chamber and wherein, in its operative position, a surface of the block abuts the rods.