In known fuel systems of gas turbines, a so-called “multi-function valve” (MFV) (see FIG. 1) exists for their oil or fuel supply. This MFV comprises a plurality of valves in order to be able to switch over between an oil supply source, a nozzle and a drain line of the fuel system. During the switchover, the valves between the respective pipelines 1 . . . n are controlled at the same time via an actuator in each case.
In this case, the pipelines, particularly in the form of burner connecting lines for diesel oil and water, have to be switched in a way that different operating modes such as diesel-oil operation, emulsion operation and also flushing and draining processes can be carried out.
There is also an actuator in order to control a plurality of like valves for the source (Q1-Qn), drain line (S1-Sn) and nozzle (N1-Nn) at the same time. These actuators are as a rule electrohydraulic. Therefore, for example “n” valves are moved in the source line by means of one actuator. Consequently, at least three actuators are required.
In addition to the closing of all the valves, the following flow connections are possible:
Source+drain line (valve in nozzle line closed),
Source+nozzle (valve in drain line closed) and
Drain line+nozzle (valve in source line closed).
Known multi-way valves are still comparatively expensive and prone to malfunction.