Gate valve apparatus

A gate valve apparatus comprising:

• a valve body having a rectilinear exhaust flow path formed therein to extend from a chamber port to a pump port;
• and
• a main valve provided in said valve body, said main valve including a main valve element and a main valve seat, said main valve element being movable within a travel space in a direction parallel to an axis of said exhaust flow path, so that when said main valve element is in a sealing position, a main valve seal for said main valve element contacts said main valve seat to block communication through said exhaust flow path, and when it is in a non-sealing position, said main valve element is separated from said main valve seat by a predetermined distance and moved in a direction perpendicular to the axis of said exhaust flow path so as to be accommodated in an accommodating chamber;
• wherein said main valve seal is provided on an abutting surface of said main valve element, and a shielding ring is secured to an outer peripheral portion of the abutting surface of said main valve element that is radially outward of said main valve seal, and further an annular groove is formed on said main valve seat, so that when said main valve element is in the sealing position, said shielding ring is positioned in said annular groove, and said main valve seal contacts said main valve seat, and when it is in the non-sealing position, said main valve element is separated from said main valve seat by a predetermined distance and moved toward an inner wall surface of said accommodating chamber to bring said shielding ring into contact with the inner wall surface of said accommodating chamber, whereby said main valve seal is shielded from radicals and plasma in exhaust gas by said main valve element, said shielding ring and the inner wall surface of said accommodating chamber.

A gate valve apparatus comprising:

• a valve body having a rectilinear exhaust flow path formed therein to extend from a chamber port to a pump port;
• and
• a main valve provided in said valve body, said main valve including a main valve element and a main valve seat, said main valve element being movable within a travel space in a direction parallel to an axis of said exhaust flow path, so that when said main valve element is in a sealing position, a main valve seal for said main valve element contacts said main valve seat to block communication through said exhaust flow path, and when it is in a non-sealing position, said main valve element is separated from said main valve seat by a predetermined distance and moved in a direction perpendicular to the axis of said exhaust flow path so as to be accommodated in an accommodating chamber;
• wherein said main valve seal is provided on an abutting surface of said main valve element, and when it is in the non-sealing position, said main valve element is moved toward an inner wall surface of said accommodating chamber and further moved in a direction parallel to the axis of said exhaust flow path so as to be pressed against the inner wall surface of said accommodating chamber, whereby a pressing surface of said main valve element is shielded from plasma.