How to conduct durability test for damping butterfly valve in electric butterfly valve:
1. The piston rod of the damping air butterfly valve is vertically installed on the endurance tester of the damping air butterfly valve by connecting the valves at both ends downwards. The first cycle of startup records the opening force and the starting force, and the second cycle records the expansion force and compression force Fl, Fz, F3, F4. From this, the nominal force, dynamic friction force, and elastic ratio of the air butterfly valve are calculated.
2. The rigidly locked damping air butterfly valve shall be locked in the midspan state to test its locking force. The measuring speed of the damping air butterfly valve durability tester is 2mm/min, and the axial compression force required to produce 1mm displacement of the piston rod is the locking force value.
3. Before testing the elastic locked damping air butterfly valve, three cycles shall be conducted under the simulated working condition, and then the valve shall be locked at the mid stroke. The measuring speed of the damping air butterfly valve durability tester is 8mm/min, and the axial compression force required to move the piston rod by 4mm is the locking force value.