Fluid control valve device

A multi-stage flow control device, comprising:

• a ceramic plug to control flow of fluid through a first and second staging portions;
• a first set of control surfaces to contact the fluid in a first staging portion;
• and
• a second set of control surfaces to contact the fluid in a second staging portion;
• wherein the control surfaces are formed in the ceramic plug such that, when the fluid flows through the first and second staging portions, the ceramic plug is adapted to operate substantially free of tensile stress concentrations along the control surfaces.

A flow control device, comprising:

• a valve body having an internal space;
• at least one plug guide disposed in the internal space;
• a ceramic plug to control flow of fluid through the internal space, the ceramic plug being slidably engaged with the plug guide so as to reciprocate in a longitudinal direction from a first operative position to a second operative position;
• and
• a plurality of grooves formed in an outer surface of the ceramic plug, the grooves extending substantially in the longitudinal direction and defining control surfaces such that, when the ceramic plug is in the first operative position, fluid flows in the grooves between the ceramic plug and the plug guide in a direction substantially parallel to the control surfaces.

A method of manufacturing a valve, comprising:

• assembling a ceramic plug into an internal space of a valve body, the plug having a longitudinal axis and a plurality of parallel grooves formed in a circumferential surface, the grooves being spaced apart along the circumferential surface and extending in a substantially longitudinal direction;
• and
• assembling at least one ceramic guide into the internal space of the valve body, the ceramic guide having a substantially cylindrical bore to slidably engage the circumferential surface of the ceramic plug;
• wherein the ceramic plug is slidably engaged with the bore of the guide to control flow of fluid through the internal space such that, when the ceramic plug is moved in the longitudinal direction to a first operative position, fluid flows between the ceramic plug and the ceramic guide in a direction substantially parallel to the grooves.

A flow control device comprising:

• a valve body having an internal space;
• at least one guide means for guiding a ceramic plug means in the internal space, said guide means disposed in the internal space;
• ceramic plug means for controlling the flow of erosive fluid through the internal space, the ceramic plug means being slidably engaged with the guide means so as to reciprocate in a longitudinal direction from a first operative position to a second operative position;
• and
• control surface means for directing the flow of fluid in the internal space, said means including a plurality of grooves formed in an outer surface of the ceramic plug means, the grooves extending substantially in the longitudinal direction and defining control surfaces such that, when the ceramic plug is in the first operative position, fluid flows in the grooves between the ceramic plug means and the guide means in a direction substantially parallel to the control surfaces.

A multi-stage flow control device, comprising:

• a plug to control flow of fluid through a first and second staging portions, wherein the plug comprises a brittle material characterized by an ultimate compression strength that is substantially greater than an ultimate tensile strength;
• a first set of control surfaces formed in the brittle material to contact the fluid in a first staging portion;
• and
• a second set of control surfaces formed in the brittle material to contact the fluid in a second staging portion;
• wherein the control surfaces are formed in the plug such that, when the fluid flows through the first and second staging portions, the plug is adapted to operate substantially free of tensile stress concentrations along the control surfaces.