To restrain a conveyed object such as artificial snow from adhering or accumulating oh a valve by inserting and fixing a base end of a seal material into the tip of a blade and making both thickness direction sides of the blade form respective one surface.

A step part 57 is formed at the tip of the back surface side of each blade body 55. A resin made seal material 58 as a clearance adjusting part has thickness thinner than the difference of the step part 57, its tip is slightly projected to the radially outer side from the tip of the blade body 55, and its base end is touched to the step part 57. A narrowly pressing band piece 59 is a band element with a length equal to the width of the blade body 55, and sandwiches the resin made seal material 58 between it and the step part 57. In the resin made seal material 58, the radially projecting amount from the blade body 55 can be freely adjusted. A blade 17 is a plane without any recessed or projecting part on the each surface side in the thickness direction of the blade body 55. Therefore, artificial snow (including flake ice) can be prevented from adhering on both sides of the blade 17.