Hot water tank for ovens made from PPS

In collaboration with Ticona and K.D. Fedderson, the German kitchen appliance manufacturer Miele Inc. has developed a new oven function for its high-performance ovens range available under the trade name H5000: these new Miele ovens are equipped with a special hot water tank that automatically takes in the right amount of water and dispenses it as jets of steam into the oven cavity. This new function, namely “moisture plus” is said to provide improved results in baking and roasting. This newly-developed hot water tank that has to withstand high temperature of up to 220°C has been made from a 15% glass fiber reinforced poly(phenylene sulphide) material i.e. Fortron™ MT9115L0 DW from Ticona by using an extrusion blow molding process. This PPS grade has been chosen because it complies with the FDA requirement and with the European 2002/72/EC directive for food contact application. Furthermore it exhibits high dimensional stability and minimal water absorption even under high thermal stresses. As for the extrusion blow molding process, it allows to eliminate the need for the subsequent welding of component that is necessary with injection molding.