Apparatus for spraying liquids, and disposable containers and liners suitable for use therewith

A gravity-fed spray gun comprising:

• a spray gun body;
• a fluid reservoir having a base and sidewalls, or sidewall in the case of a cylindrical container, the base and sidewall(s) defining an inner cavity and a fill opening;
• a removable, collapsible, self-supporting liner, the liner having a base and sidewalls, or a sidewall, defining an inner cavity, and a fill opening;
• a lid for the fill opening of the reservoir and liner, the lid having a fluid outlet adapted to connect to the spray gun body, wherein the spray gun further comprises a spray nozzle for dispensing fluid from within the liner;
• and
• wherein the liner collapses when fluid is withdrawn from within the liner during operation of the gun, and in which the combination of reservoir and liner has a fill opening which is inverted when connected to the spray gun body in normal operation with fluid passing from within the liner to the spray nozzle, and wherein the liner is removable from the reservoir together with the lid, and the combination of reservoir, liner and lid is removable from the spray gun body.