In the mixing of gas or liquid streams, it is often important to adapt the pressure of one medium always to the fluctuating pressure of the other medium. In this way, the mixture ratio can be kept constant. The invention describes a pressure controller which adjusts the high pressure in one conduit to the pressure which prevails in a conduit with a lower pressure. One exemplary application is the through-flow heater in hot-water supply. Temperature fluctuations which occur when several consumers extract warm water can thus be avoided.
