Hydrodynamic machine and method for minimizing the drag power of such a machine

A method for minimizing a drag power of a hydrodynamic machine, said method comprising the steps of:

• providing that the hydrodynamic machine has an external working medium circuit and is a retarder, the hydrodynamic machine including:
• a bladed primary wheel;
• a bladed secondary wheel, said primary and secondary wheels together forming a toroidal working chamber which is configured for being filled with a working medium from the external working medium circuit, the hydrodynamic machine being configured such that said working medium is fed back into the external working medium circuit;
• an annular channel disposed outside said working chamber, said annular channel being connected in a working-medium conducting manner to said working chamber via a plurality of outlet holes in one of said primary wheel and said secondary wheel, said annular channel being in a flow-conducting communication with the external working medium circuit in order to collect said working medium leaving said working chamber through said plurality of outlet holes and supply said working medium leaving said working chamber through said plurality of outlet holes to the external working medium circuit;
• at least one tapping opening disposed one of on and outside said working chamber, said at least one tapping opening being in a flow-conducting communication with said working chamber of the hydrodynamic machine;
• at least one filling channel which opens into a region of relatively low working medium pressure inside the hydrodynamic machine and which is in a flow-conducting communication with said working chamber;
• a return line, wherein said at least one tapping opening and said at least one filling channel are interconnected in a working-medium conducting manner by way of said return line outside the external working medium circuit in such a manner that said working medium flows from said at least one tapping opening into said at least one filling channel and from said at least one filling channel back into said working chamber so that a working medium circuit is established outside the external working medium circuit;
• a collecting container;
• a second valve;
• and
• one of a first valve and a diaphragm, when viewed in a direction of flow of said working medium (a) one of said first valve and said diaphragm, (b) said collecting container, and (c) said second valve being disposed successively in said return line;
• filling said collecting container with said working medium from said working chamber via an additional working medium outlet by one of closing said second valve and keeping closed said second valve and, if provided, by one of opening said first valve and keeping open said first valve when deactivating the hydrodynamic machine;
• and
• emptying said collecting chamber via said at least one filling channel by opening said second valve and, if present, by closing said first valve one of when activating the hydrodynamic machine and when the hydrodynamic machine is activated.