Gate valve for vacuum and seal member used therefor
A gate valve for vacuum capable of preventing a seal member from being cracked or particles from being produced due to a stress concentration even if the seal member is repeatedly compressed in the state that the adhesive agent is separated from the open side of a seal member mounting groove and capable of suppressing particles from being produced due to the rub of the seal top part with the seal surface.
1. A gate valve for vacuum comprising a plate body formed in such a manner that the outer end of a seal member mounting groove is opened and a seal member that is mounted in the seal member mounting groove of the plate body and that is made of an elastic material having no edge,
wherein the cross-sectional shape of the seal member is formed in a generally chevron shape with an apex T, an outer sloped surface is formed on the lateral outer side of the seal member mounting groove outside from the apex T, an inner sloped surface is formed on the lateral inner side of the seal member mounting groove inside from the apex T, and the apex T is positioned on the inner side of the seal member mounting groove from the position by S/2, and θ 1 is larger than θ 2 , where θ 1 is an inclination of the outer sloped surface, θ 2 is an inclination of the inner sloped surface, and S is a width of the bottom surface of the seal member mounting groove.
2. The gate valve for vacuum as defined in claim 1 , further comprising a bent point P formed at the lower section of the outer sloped surface and a bottom part in which an inclination of a section on the lateral outer side of the seal member mounting groove outside from the bent point P is gradually decreased.
3. A seal member having a cross-sectional shape of a generally chevron shape with an apex T, said seal member placed in a mounting groove of a gate valve, and comprising an outer sloped surface formed on the lateral outer side of the seal member mounting groove outside from the apex T, and an inner sloped surface formed on the lateral inner side of the seal member mounting groove inside from the apex T, wherein the apex T is positioned on the inner side of the seal member mounting groove from the position by S/2, and θ 1 is larger than θ 2 , where θ 1 is an inclination of the outer sloped surface, θ 2 is an inclination of the inner sloped surface, and S is a width of the bottom surface of the seal member mounting groove.