Lever operated dump valve with improved accuracy

A liquid level control system for controlling the level of liquid in a vessel, the system comprising:

• a float;
• a float arm having a first end and a second end, the first end supporting the float and the second end having a splined bore;
• a trunnion assembly attachable to the vessel, the trunnion assembly comprising:
• a trunnion lever having a splined bore at one end;
• and
• a trunnion shaft having a first splined section and a second splined section, wherein the first splined section is matingly engaged with the splined bore of the float arm so the float arm is non-rotative relative to the trunnion shaft and the second splined section is matingly engaged with the splined bore of the trunnion lever so the trunnion shaft is non-rotative relative to the trunnion lever;
• a mechanical dump valve assembly, comprising:
• a dump valve lever having a splined bore at one end thereof;
• a dump valve shaft having a first splined section and a second splined section, wherein the first splined section is matingly engaged with the splined bore of the dump valve lever so the dump valve lever is non-rotative relative to the dump valve shaft;
• and
• a dump valve comprising:
• a valve body with an inlet fluidly connectable to an input line from the vessel and an outlet fluidly connectable to an output line;
• a valve member positioned in the valve body and movable between an open position and a closed position to control passage of fluid from the inlet to the outlet;
• a valve actuator connected to the valve member to operate the valve member between the open position and the closed position;
• and
• a dump valve hub having a first end connected to the valve actuator and a splined bore wherein the second splined section of the dump valve shaft is matingly engaged with the splined bore of the dump valve hub so the dump valve shaft is non-rotative relative to the dump valve hub;
• and
• a linkage rod operatively connecting the trunnion lever to the dump valve lever whereby trim motion of the float arm controls the operation of the dump valve.

A trunnion assembly for use with a mechanical dump valve in a liquid level control system for controlling the level of liquid in a vessel, wherein the liquid level control system comprises a float arm having first and second ends, and a float attachable to the first end of the float arm, the trunnion assembly comprising:

• a bonnet attachable to the vessel;
• a float arm hub having one end attachable to the second of the float arm and a splined bore;
• a trunnion lever having a splined bore at one end;
• and
• a trunnion shaft having a first splined section and a second splined section, the first splined section of the trunnion shaft matingly engaged with the splined bore of the trunnion lever so the trunnion shaft is non-rotative relative to the trunnion lever and the second splined section matingly engaged with the splined bore of the float arm hub so the float arm hub is non-rotative relative to the trunnion shaft.

A retrofit kit for a liquid level control system for controlling the level of liquid in a vessel, wherein the system comprises a float, a float arm, a trunnion assembly, a dump valve assembly, and a linkage rod, wherein the trunnion assembly comprises a float arm hub pivotally mounted in a bonnet, a trunnion lever having a D-shaped bore, a trunnion shaft having a first D-shaped section receivable in the D-shaped bore of the float arm hub and a second D-shaped section receivable in the D-shaped bore of the trunnion lever, whereby trim motion of the float is transmitted to the trunnion lever, and wherein the dump valve assembly comprises a lever having a D-shaped bore, a valve body fluidly coupled to the vessel, a valve member in the valve body configured to control the flow of fluid through the valve body, a pivotally mounted dump valve hub operatively connected to the valve member and having a D-shaped bore, a shaft having a first D-shaped section receivable in the D-shaped bore of the dump valve hub and a second D-shaped section receivable in the D-shaped bore of the dump valve lever, whereby motion of the dump valve lever is transmitted to the trunnion hub for operating the valve, the retrofit kit comprising:

• a replacement float arm hub having an internally splined bore and configured to replace the float arm hub in the liquid level control system;
• a replacement trunnion lever having a splined bore at one end thereof;
• a replacement trunnion shaft having a first splined section and a second splined section, the first splined section of the replacement trunnion shaft matingly engageable with the splined bore of the replacement trunnion lever so the replacement float arm hub is non-rotative relative to the replacement trunnion lever and the second splined section of the replacement trunnion shaft matingly engageable with the splined bore of the replacement float arm hub so the replacement float arm hub is non-rotative relative to the replacement trunnion shaft;
• a replacement dump valve lever having a splined bore at one end thereof;
• a replacement dump valve hub operatively connectable to the valve member and having a splined bore;
• a replacement dump valve shaft having a first splined section and a second splined section, the first splined section of the replacement dump valve shaft matingly engagable with the splined bore of the replacement dump valve lever so the replacement dump valve lever is non-rotative relative to the replacement dump valve shaft and the second splined section of the replacement dump valve shaft matingly engageable with the splined bore of the replacement dump valve hub so the replacement dump valve shaft is non-rotative relative to the replacement dump valve hub, whereby motion of the replacement dump valve lever is transmitted to the valve member for operating the valve.