A channel block for a liquid chemical dosing apparatus. The channel block has a process outlet; a chemical liquid inlet; an evacuation outlet; a calibration column outlet; channels provided within the channel block that connect at least the process outlet, the chemical liquid inlet, the evacuation outlet and the calibration column outlet; a pressure indicator mounted to the channel block to measure the pressure of the chemical liquid entering through the chemical liquid inlet; a additional regulation valve mounted to the channel block upstream of at least one of the process outlet and the calibration column outlet; a evacuation regulation valve mounted to the channel block upstream of the evacuation outlet; at least three control valves mounted to the block configured to control the chemical liquid passing through the channels.