Isolation valve

A chamber system, comprising:

• a first chamber unit;
• a second chamber unit;
• and
• an isolation valve coupled to the first chamber unit and the second chamber unit and configured to control fluid flow between the first chamber unit and the second chamber unit, wherein the isolation valve comprises:
• a valve body defining a first port providing fluid access to the first chamber unit, and a bottom wall defining a seating surface and a second port providing fluid access to the second chamber unit, wherein the first port is fluidly coupled with a first fluid source, and a shielding gas source is in fluid contact with the first port or a shielding gas inlet that is fluidly coupled with the first chamber unit;
• and
• a flapper disposed inside the valve body having a flapper surface, wherein the flapper is pivotable within the valve body to a first position such that the flapper surface is away from the seating surface defined by the valve body to allow fluid flow between the first chamber unit and the second chamber unit, wherein the flapper is further pivotable within the valve body to a fully pivoted position such that the flapper surface is parallel and proximate to the seating surface and planar across the second port to restrict fluid flow between the first chamber unit and the second chamber unit, wherein when the flapper is in the second position, the seating surface and the flapper surface form a non-contact seal to restrict fluid flow between the first chamber unit and the second chamber unit to a low flow conductance.

A method, comprising:

• closing an isolation valve coupled with a first chamber unit and a second chamber unit, wherein the isolation valve is operable to control fluid flow between the first chamber unit and the second chamber unit, wherein the isolation valve comprises:
• a valve body defining an inlet port providing fluid access to the first chamber unit, a first fluid volume fluidly coupled with the first chamber unit, and a second fluid volume fluidly coupled with the second chamber unit, wherein the inlet port is fluidly coupled with a first gas source and a shielding gas source is in fluid contact with the inlet port or a shielding gas inlet that is fluidly coupled with the first fluid volume;
• and
• a flapper disposed inside the valve body having a flapper surface, wherein the flapper is pivotable within the valve body to a first position such that the flapper surface is away from a seating surface defined by the valve body to allow fluid flow between the first chamber unit and the second chamber unit, wherein the flapper is further pivotable within the valve body to a fully pivoted position such that the flapper surface is proximate the seating surface to restrict fluid flow between the first chamber unit and the second chamber unit, wherein when the flapper is in the fully pivoted position, the seating surface and the flapper surface form a non-contact seal to restrict fluid flow between the first chamber unit and the second chamber unit;
• and
• flowing a shielding gas into the first fluid volume when the flapper is in the fully pivoted position.