US Patent 8191733 Arrangement for dispensing colour paste, apparatus and method

An arrangement for dispensing color paste, a shading apparatus, a method, a computer program product, and a memory. The arrangement includes a piston pump including a feed channel. The feed channel is provided with a substantially different amount of color paste per travelling length unit when the piston is moving towards the first end of the cylinder than when the piston is moving towards the second end of the cylinder. The arrangement further includes a valve connected to the feed channel, a dispensing channel connected to a first outlet channel of the valve for conveying color paste into a can, and a by-pass feed channel connected to a second outlet channel of the valve for conveying color paste past the can for the paint to be shaded.