Device and method of preparing salt-containing water by reverse osmosis

An apparatus that treats salt-containing water by reverse osmosis, in which the salt-containing water is separated into a permeate stream and a concentrate stream, comprising:

• an inlet for the salt-containing water;
• an outlet for the permeate;
• an outlet for the concentrate,
• a reverse osmosis device, and
• a blending device comprising a channel delimited by a wall;
• and
• a valve body mounted in an axially displaceable and/or rotationally movable manner within the channel;
• wherein
• the inlet and the outlets are integrated into a base unit adapted for installation in a fixed position,
• the reverse osmosis device is an exchangeable unit detachably connected to the base unit,
• the valve body is a constituent part of the base unit, and
• the channel is, together with the wall delimiting the channel, a constituent part of the exchangeable unit.