The invention belongs to the technical field of funnel caps, and particularly relates to a boiler funnel cap used in the power
plant field. The boiler funnel cap comprises a funnel cap conical cover,a funnel cap sleeve, funnel cap holes and an executing mechanism, a
turbine drives a rotation shaft to rotate after being blown by wind, and
volute spiral springs are compressed to store energy; and after the
turbine is blown by wind to rotate, lead screws in an anti-blocking mechanism can be quickly separated from the funnel cap holes, and the funnel cap can be normally ventilated. After the funnel cap stops being blown by wind, the
volute spiral springs release energy; the rotating speed of the rotation shaft can be limited through design of frictional arc-shaped plates in a gear shifting mechanism, then the effect of decreasing the releasing speed of the
volute spiral springs is achieved, and it is guaranteed that the rotation shaft drives loop sleeves to rotate at
low speed through a first shaft sleeve, connecting plates and a gear ring; and in addition, the lead screws in the anti-blocking mechanism can slowly penetrate through the funnel cap holes in a rotating mode, therefore, it is guaranteed that the lead screws can extrude out high-temperature small-particle
coal in the funnel cap holes, it is guaranteed that high-temperature small-particle
coal near the outer sides of the funnel cap holes can not enter the funnel cap holes, and the condition that the funnel cap holes are blocked is finally avoided.