The invention relates to the technical field of valves, and discloses a manual operation mechanism for a valve, which comprises a flux sleeve, a plug, a connecting rod and a
piston, the flux sleeve is provided with a
piston cavity, the plug is fixedly mounted at the
tail end of the flux sleeve, the connecting rod axially penetrates into the
piston cavity, one end of the connecting rod is directly or indirectly connected with a valve core of the valve, and the other end of the connecting rod penetrates out of the plug. The piston is arranged in the piston cavity and is in axial sliding sealing fit with the piston cavity, the piston is provided with at least two shaft sections with different diameters, a working medium can act on the piston, the piston generates acting force far away from the
plug in the axial direction, the connecting rod is in axial limiting fit with the piston, and the acting force far away from the plug borne by the piston can be transmitted to the connecting rod. And the opposite acting force towards the plug on the connecting rod is balanced. Compared with a traditional scheme that a spring is adopted to balance the opposite acting force borne by the connecting rod and facing a plug, mutual
dynamic balance can be achieved within the range of all working conditions from low pressure to
high pressure, and the effect of labor-saving operation under all working conditions is achieved.