| 摘要 |
PROBLEM TO BE SOLVED: To provide a butterfly valve reduced in the cost of a valve element of the butterfly valve, light in the weight, superior in heat resistance, chemical resistance, and water resistance and provided with the dimension stability equivalent to a metal material. SOLUTION: The valve element of the butterfly valve is formed of a molding composed of a thermosetting resin molding material containing a reinforced fiber and a shaft hole of the valve element of the butterfly valve and a polygonal shaft hole corresponding to the shaft hole are integrally formed so as to attain the prescribed purpose.
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