HYDRAULIC CONTROL UNIT FOR BLADES OF FAN IMPELLER Russian patent published in 2012 - IPC F04D29/36 F04D29/32 F04D19/00 F01D5/00 

FIELD: machine building.

SUBSTANCE: hydraulic control unit for blades (2) of impeller (1) of the axial fan comprises regulating cylinder (6), which has first chamber (11) and second chamber (12) on both sides of internal moving piston (7); each of the chambers is linked with control channels (A, B) through connections (14, 15). Control channels (A, B) are connected to the 4-stroke valves. Both supply channel (P) leading to one of control channels (A) and outlet channel (T) connected to another control channel (B) are split into two parallel branches (P1/A1, P2, A2, T1/B1, T2/B2). There are two auxiliary 4-stroke valves (23), (33), each of which is built into one of parallel branches (P1, A1 or P2, B2) and (T1, B1 or T2, B2). There is seated valve (24), (25), (34), (35) closing with a spring force and installed in each branch (A1, A2) of one control channel (A) and in each branch (B1, B2) of the other control channel (B) between relevant connections (14), (15) and corresponding 4-stroke valves (23), ( 33).

EFFECT: control of the blades that ensures that even in case of power failure it is possible to keep the blades in their last position before the incident until another control unit takes over control of the blades position after switching over of the mains supply.

11 cl, 4 dwg