Inline heater

A heat spreader assembly for a liquid heater, said heat spreader assembly comprising:

• a tubular heat spreader that extends axially along a longitudinal axis and that comprises an external surface;
• at least one conduit that extends helically about said longitudinal axis of said heat spreader;
• a fluid inlet and a fluid outlet fluidically connected by said at least one conduit such that a fluid heating flow path is defined by said at least one conduit between said fluid inlet and said fluid outlet;
• an electrically operated heating element for heating the heat spreader;
• said heat spreader comprising at least one heat transfer channel that extends helically about said external surface, wherein said at least one conduit is seated in said at least one heat transfer channel;
• said at least one heat transfer channel comprising opposite first and second side walls and bottom wall, wherein said at least one conduit is in contact with said first and second side walls and said bottom wall;
• a purge manifold that externally covers said heat spreader and closes said at least one heat transfer channel such that purge passages are defined between the channel walls and the purge manifold around the at least one conduit.