Liner displacement control valve including valve trim with spindle and flow control element for improved low flow control

A control valve for regulating the flow of a fluid, the valve comprising:

• a housing defining a fluid inlet and a fluid outlet;
• a flow control element disposed within the housing between the fluid inlet and the fluid outlet, the flow control element including a bore defined by an inner surface thereof which is of a prescribed inner diameter, the flow control element being configured to dissipate energy in a fluid flowing therethrough from the fluid inlet to the fluid outlet;
• a spindle disposed within the housing and reciprocally moveable between closed and open positions relative thereto, the spindle including a shank portion having a generally cylindrical needle portion which protrudes therefrom and is of a prescribed outer diameter, the needle portion including at least one labyrinth groove formed therein, the bore of the flow control element accommodating at least part of the needle portion when the spindle is in either of the open and closed positions, the outer diameter of the needle portion and the inner diameter of the flow control element being sized relative to each other such that a prescribed dimensional tolerance therebetween, in combination with the at least one labyrinth groove, substantially mitigates any high velocity annular fluid flow between the flow control element and the spindle when the spindle is moved to the open position;
• and
• a stem which is operatively coupled to the spindle by a stem adaptor adapted to allow for a prescribed amount of movement of the spindle relative to the stem and the flow control element during the movement of the spindle between the open and closed positions.

A control valve for regulating the flow of a fluid, the valve comprising:

• a housing defining a fluid inlet and a fluid outlet;
• a flow control element disposed within the housing between the fluid inlet and the fluid outlet, the flow control element being configured to dissipate energy in a fluid flowing therethrough from the fluid inlet to the fluid outlet;
• and
• a spindle disposed within the housing and reciprocally moveable between closed and open positions relative thereto, the spindle including a multiplicity of labyrinth grooves formed therein in series, the labyrinth grooves being sized and configured to mitigate any high velocity annular fluid flow between the flow control element and the spindle when the spindle is moved to the open position;
• wherein each of the labyrinth grooves has a generally square profile with sharp edges, and is formed to be of a depth of about 0.02 inches and a width of about 0.02 inches.