Vortex flush ball valve and method

A method for purging a cavity in a ball valve, comprising:

• providing a ball valve comprising:
• a flow control element rotatably disposed in a valve body and defining a cavity between an outer spherical surface of the flow control element and an inner surface of the valve body;
• a purge fluid inlet passage through the valve body to the cavity having a flow axis directed toward or tangential to the outer spherical surface at a location and having an orientation of the flow axis of the purge fluid inlet passage transverse to a normal line to the spherical surface at the location, wherein the purge fluid inlet passage flow axis is at an angle from 30 to 90 degrees with respect to the normal line;
• and
• a purge fluid drain from the cavity through the valve body located below the flow control element at an axis of rotation of the flow control element;
• introducing a purge fluid into the purge fluid inlet passage;
• with the purge fluid drain closed, operating the flow control element to provide communication and then terminate the communication between the cavity and a process fluid in a process flow passage through the flow control element;
• then opening the purge fluid drain to create a vorticial flow path through the cavity from the purge fluid inlet passage to the purge fluid drain;
• flushing debris from the cavity;
• closing the purge fluid drain, and
• introducing the purge fluid into the cavity between operating cycles to provide a positive pressure in the cavity greater than a pressure of the process fluid in the process flow passage.

A method for purging a cavity in a ball valve, comprising the steps of:

• (a) providing a ball valve comprising:
• a flow control element rotatably disposed in a valve body and defining a cavity between an outer spherical surface of the flow control element and an inner surface of the valve body;
• a purge fluid inlet passage through the valve body to the cavity having a flow axis directed toward or tangential to the outer spherical surface at a location and having an orientation of the flow axis of the purge fluid inlet passage transverse to a normal line to the spherical surface at the location, wherein the purge fluid inlet passage flow axis is at an angle from 30 to 90 degrees with respect to the normal line;
• and
• a purge fluid drain from the cavity through the valve body located below the flow control element at an axis of rotation of the flow control element;
• (b) supplying a purge fluid to the purge fluid inlet passage to provide a positive pressure in the cavity greater than a pressure of a process fluid in a process flow passage through the flow control element;
• (c) with the purge fluid drain in a closed position while supplying the purge fluid to the purge fluid inlet passage, operating the flow control element to provide communication between the cavity and the process fluid;
• (d) operating the flow control element to terminate the communication between the process fluid and the cavity;
• (e) while supplying the purge fluid to the purge fluid inlet passage, opening the purge fluid drain to create a vorticial flow path through the cavity from the purge fluid inlet passage to the purge fluid drain and flush debris from the cavity;
• (f) closing the purge fluid drain;
• (g) supplying the purge fluid to the purge fluid inlet passage to provide the positive pressure in the cavity greater than the pressure of the process fluid in the process flow passage through the flow control element;
• (h) cyclically repeating steps (c) to (g) a plurality of times.

A method for purging a cavity in a ball valve, comprising:

• providing a ball valve comprising:
• a flow control element rotatably disposed in a valve body and defining a cavity between an outer spherical surface of the flow control element and an inner surface of the valve body;
• a first purge fluid inlet passage through the valve body to the cavity having a flow axis directed toward or tangential to the outer spherical surface at a first location and having an orientation of the flow axis of the first purge fluid inlet passage transverse to a normal line to the spherical surface at the first location;
• a second purge fluid inlet passage through the valve body to the cavity having a flow axis directed toward or tangential to the outer spherical surface at a second location and having an orientation of the flow axis of the second purge fluid inlet passage transverse to a normal line to the spherical surface at the second location;
• and
• a purge fluid drain from the cavity through the valve body located below the flow control element at an axis of rotation of the flow control element;
• introducing a purge fluid into the first purge fluid inlet passage, into the second purge fluid inlet passage, or both;
• and
• simultaneously removing the purge fluid from the cavity through the purge fluid drain to create a vorticial flow path through the cavity from the first purge fluid inlet passage to the purge fluid drain, from the second purge fluid inlet passage to the purge fluid drain, or both;
• wherein the angles of the flow axes of the first and second purge flow inlet passages with respect to the respective normal lines are oriented in the same azimuthal direction to reinforce vorticial purge fluid flow paths from the inlet passages to the purge fluid drain.

A method for purging a cavity in a ball valve, comprising:

• providing a ball valve comprising:
• a flow control element rotatably disposed in a valve body and defining a cavity between an outer spherical surface of the flow control element and an inner surface of the valve body;
• a first purge fluid inlet passage through the valve body to the cavity having a flow axis directed toward or tangential to the outer spherical surface at a first location and having an orientation of the flow axis of the first purge fluid inlet passage transverse to a normal line to the spherical surface at the first location;
• a second purge fluid inlet passage through the valve body to the cavity having a flow axis directed toward or tangential to the outer spherical surface at a second location and having an orientation of the flow axis of the second purge fluid inlet passage transverse to a normal line to the spherical surface at the second location;
• and
• a purge fluid drain from the cavity through the valve body located below the flow control element at an axis of rotation of the flow control element;
• introducing a purge fluid into the purge fluid inlet passage;
• and
• simultaneously removing the purge fluid from the cavity through the purge fluid drain;
• wherein the first location is disposed on a hemisphere of the flow control element opposite the purge fluid drain and the second location is disposed on the same hemisphere as the purge fluid drain.