Abstract: A mixing valve controlled with one operating lever and comprising a first fixed ceramic plate with inlet openings communicating with inlet pipes for cold and hot water respectively and with a discharge opening for the controlled water amount; and a second ceramic plate cooperating with said first ceramic plate and being movable by means of said operating lever in order to control the total amount and the mixing ratio of cold and hot water; said mixing valve further comprising a fixed channel member, which is attached to and movable with the second ceramic plate, said channel member and said second ceramic plate forming together separate non-communicating channels for cold and hot water respectively, so that the cold and hot water are not intermixed until reaching the discharge opening. Preferably, the channel member is of plastic material and sealed in relation to the second ceramic plate by means of a sealing ring surrounding the separate channel parts.

Abstract: The connecting pipe portion between the outlet pipe and the drain pipe of a wash basin is surrounded by an electric heater for heating the interior of the connecting pipe portion to a temperature of about 80.degree. to 100.degree.C to prevent microbes from rising from the drain pipe into the outlet pipe. The connecting pipe portion comprises a metal ring having a heating coil wound thereon and being thermally insulated from the outlet pipe and drain pipe by insulating rings. The outlet pipe may include a conical stub pipe projecting into the ring and spaced therefro by an air gap.