A pneumatic control device for needle valves in injection molding systems. The control device has a control piston, a needle valve,BALANCING VALVES a control cylinder and a cylindrical receptacle in which the control cylinder is positioned. The needle valve is adjustably secured to the piston.Needle Valves The control cylinder has channels for supplying and removal of pressure gas from two cylindrical chambers separated by the control piston. The control cylinder is firmly positioned against the surface of the recess in which it is situated. A plurality of seals positioned between the contact surfaces define two chambers separated from one another.Butterfly Valves A pressure gas channel is connected to each of the chambers for supply and removal of pressurized gas into and out of the chambers which control the movement of the control piston and thus the needle valve. A space is left between the recess in the control receptacle and the control cylinder in order to allow the control cylinder to shift laterally due to the occurrence of lateral forces exerted on the needle valve.

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