초록 ▼

An erosion resistant control valve or adjustable choke has a body with a side inlet, an end outlet and a conical valve seat in alignment with the outlet. Downstream from the valve seat are a converging passage having a smaller taper than the valve seat, a cylindrical passage and a diverging passage.

An erosion resistant control valve or adjustable choke has a body with a side inlet, an end outlet and a conical valve seat in alignment with the outlet. Downstream from the valve seat are a converging passage having a smaller taper than the valve seat, a cylindrical passage and a diverging passage. A stem aligned with the seat assembly includes a plug having a tapered seal surface near its upstream end for engaging the valve seat and a converging control surface downstream therefrom with the same taper as the converging passage. The smaller end of the control surface is in the cylindrical passage when the valve is closed and in the converging passage is fully open for localizing erosion downstream from the valve seat. A bleed passage relieves pressure from within the valve before the valve bonnet can be removed. The valve can be locked in a selected control setting by a split ring engaging the stem.

대표청구항 ▼

A high pressure adjustable choke comprising: a valve body having a side inlet passage and an end outlet passage having a diverging portion; a removable seat assembly mounted in the body in alignment with the outlet passage, including a support sleeve slidably fitted into the valve body; means for se

A high pressure adjustable choke comprising: a valve body having a side inlet passage and an end outlet passage having a diverging portion; a removable seat assembly mounted in the body in alignment with the outlet passage, including a support sleeve slidably fitted into the valve body; means for sealing between the support sleeve and the valve body; and an erosion resistant sleeve having a conical valve seat tapering inwardly at an angle of about 30°at its inlet end, a conical converging passage having a taper of about 10°downstream from the valve seat, a cylindrical passage immediately downstream from the converging passage, and a diverging passage immediately downstream from the cylindrical passage aligned with the diverging portion of the outlet passage; an axially movable stem aligned with the seat assembly, including an erosion resistant plug having a conical seal surface near its upstream end having a taper of about 30°for engaging the valve seat in the sleeve and a converging conical control surface downstream from the seal surface with the same taper as the converging passage; means for moving the stem between a closed position with the seal surface on the plug engaging the valve seat in the sleeve and a fully open position wherein the smaller end of the control surface is within the converging passage, the flow cross section of the annulus between the control surface of the plug and the converging passage in the fully open position being about the same as the flow cross section through the cylindrical passage and including a clearance between the control surface and the converging passage when the seal surface engages the valve seat; the length of the control surface being greater than the length of the converging passage and greater than the length of the stroke of the stem between the open and closed positions, the length of the converging passage in the sleeve being less than the stroke of the stem between the open and closed positions, and the total length of the converging passage and the cylindrical passage being greater than the length of the control surface on the plug so that a vena contracta of fluid flowing through the valve can occur in the liner sleeve downstream from the valve seat in all positions of the valve stem between the closed position and the fully open position and including the fully open position; a removable bonnet surrounding the stem for retaining the stem in the valve body; a seal between the valve bonnet and the valve body; and a removable cage between the bonnet and seat assembly lining the valve body and including a side opening aligned with the inlet passage.