Flow-control valve

A flow-control valve for liquid-conducting heating or cooling systems, the flow-control valve comprising:

• a housing having an inlet port, an outlet port, and a connection fitting therebetween;
• a flow-control assembly in the connection fitting of the housing between the inlet port and the outlet port;
• a pressure-control assembly in the housing that maintains constant a pressure differential between the input and output pressures upstream of and downstream of the flow-control assembly in the connection fitting;
• a spindle with an actuating element projecting out of the housing;
• a first valve subassembly in the flow-control assembly having a first seat on the housing and a first valve body in the housing fixed on the spindle, engageable with the first seat, and acting on the flow-control assembly or on parts thereof;
• and
• a second valve subassembly in the flow control assembly and formed from a second valve body on the spindle so as to be displaceable therealong and a second seat for the second valve body and formed in the first valve body, the second valve body being displaceable toward and away from the second seat of the first valve body such that a cross section of a flow passage through the connection fitting can be varied by the flow-control valve.