US Patent 9074692 Valve manifold

A valve manifold has a housing including a central mixing chamber and a shell surface. The shell surface has at least two valve ports that are each associated with one valve. A first valve port has three openings and the additional valve ports each have at least two, preferably three openings. A respective first opening of the valve ports is in direct fluid communication with the central mixing chamber, and the second and third openings of the valve ports are each in fluid communication with an inflow or outflow via a duct. An external port is provided which is in direct fluid communication with the mixing chamber via a duct.