Fine control gas valve

A fine control gas valve, comprising:

• a tee having opposed first and second tee runs co-axially aligned on a longitudinally axis, and a tee branch oriented perpendicular to the longitudinal axis;
• a valve assembly partially received in and connected to the first tee run, the valve assembly having a valve disc connected to a drive screw and longitudinally moved by axial rotation of the drive screw, the valve disc including:
• a disc columnar portion oriented perpendicular to a disc flange;
• a disc curved portion tangentially extending from the disc columnar portion and oppositely directed from the disc flange;
• and
• a first disc slot having a first end positioned in the disc columnar portion and extending to a second end positioned in the disc curved portion, the second end of the first disc slot defining a slot end arc tangentially interfacing with the disc curved portion.

A fine control gas valve, comprising:

• a tee having opposed first and second tee runs co-axially aligned on a longitudinally axis, and a tee branch oriented perpendicular to the longitudinal axis;
• a valve assembly partially received in and connected to the first tee run, the valve assembly having a valve disc connected to a drive screw and longitudinally moved by axial rotation of the drive screw, the valve disc including:
• a first slot created on the valve disc having a first end and a second end wider than the first end;
• and
• a second disc slot created on the valve disc in a mirror image of the first disc slot;
• a pipe received in the second tee run having first portion of a pipe end face/seat surface in direct contact with a shoulder created in a wall of the second tee run, the valve disc when contacting a second portion of the pipe end face/seat surface defining a valve closed condition, the first and second portions of the pipe end face/seat surface being co-planar to each other;
• and
• the valve assembly includes an indicator sleeve having a cylindrical body portion received in the first tee run and fixed to the first tee run by fasteners extending through the first tee run into the cylindrical body portion to fix the cylindrical body portion against rotation with respect to the tee.

A method to control gas flow using a fine control gas valve, the fine control gas valve having a tee with first and second tee runs and a perpendicularly oriented tee branch, and a valve assembly having a valve disc connected to a drive screw having a disc flange, the method comprising:

• connecting the valve assembly in the first tee run;
• orienting a disc columnar portion of the valve disc perpendicular to the disc flange;
• creating a disc curved portion of the valve disc tangentially extending from the disc columnar portion;
• forming a pie-shaped disc slot on the valve disc having a first end positioned in the disc columnar portion and a second end wider than the first end positioned in the disc curved portion, a width of the first disc slot continuously increasing to the second end which further defines a slot end arc;
• and
• axially rotating the drive screw to longitudinally displace the valve disc away from a valve closed condition having the disc flange in contact with a seat surface such that the first end of the disc slot passes the seat surface initially, followed by the second end of the disc slot passing the seat surface, thereby increasing an exposed area of the disc slot permitting increasing discharge flow from the fine control gas valve through the disc slot as the disc slot is exposed with respect to the seat surface from the first to the second end.