1. An actuating drive for a regulation valve, comprising:a spring;
a working cylinder having a piston and a piston rod connected to said piston, said piston rod forming an actuator for the regulation valve, said piston delimiting a first pressure chamber of said working cylinder, said first pressure chamber having a first pressure port for an introduction of a pressurized working medium for displacing said piston with said piston rod, by exertion of pressure, counter to a force of said spring assigned to said working cylinder;
an external working medium circuit connected to said working cylinder for selectively introducing the pressurized working medium into or discharging the pressurized working medium from, said first pressure chamber, said external working medium circuit having a pressure line, a valve, a motor and a working medium pump driven by means of said motor, said working medium pump being connected to said first pressure port of said first pressure chamber by means of said pressure line being connected to a pressure side of said working medium pump, wherein said valve being a check valve or a shut-off valve opening in a direction of said first pressure port and disposed in said pressure line;
a short-circuit line branching off from said pressure line upstream of said check valve or said shut-off valve as viewed in a flow direction of the pressurized working medium, said short-circuit line connecting said pressure line to a suction side of said working medium pump while bypassing said working cylinder; and
a short-circuit valve disposed in said short-circuit line and by means of said short-circuit valve, said the short-circuit line can be selectively shut off for prevention of a throughflow of the pressurized working medium to said suction side;
said short-circuit valve being an unregulated open/closed valve which has only two switching positions including: a first switching position, in which said short-circuit valve blocks a flow cross section of said short-circuit line for prevention of a throughflow of the pressurized working medium to said suction side, and a second switching position, in which said short-circuit valve opens up the flow cross section of said short-circuit line; and
said second switching position being a de-energized state of said short-circuit valve, and said first switching position being an activated state of the short-circuit valve.