PNEUMATIC CONTROL VALVE COMPRISING SEVERAL C-PISTONS

摘要

The invention relates to a pneumatic control valve as an actuator for a regulated application of compressed air to a brake cylinder (8), which can be connected to a valve housing (1) via a C-port (7), in accordance with a pressure difference between a control pressure supplied by an S-port (3) and a reference pressure which is supplied via an A-port (4) and acts in the opposite direction on a control piston (2). According to the invention, said control piston, in cooperation with at least one pressure spring (5), actuates a double-seat valve (6) either for connecting the C-port (7) to an O-port (9) for discharging air or for connecting the C-port (7) to an R-port (10) for ventilation. Several additional C-pistons (12a, 12b), which cooperate with the control piston (2) and can be alternatively selected, are provided for adjusting several brake pressure levels, wherein a first C-piston (12a) having a smaller diameter and an associated C1-port (13a) is arranged on the piston rod (11), which actuates the double-seat valve (9), at a distance from a second C-port (12b) having a larger diameter and an associated C2-port (13b), wherein a first brake pressure level can be adjusted by subjecting the first C-piston (12a) to a brake cylinder pressure, a second brake pressure level can be adjusted by subjecting the second C-piston (12b) to a brake cylinder pressure and a third brake pressure level can be adjusted by subjecting both C-pistons (12a, 12b) to the brake cylinder pressure.