Fixed cone valves have proven themselves as reliable and versatile pressure retaining valves for over a century. As one of the earliest pressure vessel isolation devices developed, their design advantages still make them the prudent choice for critical applications today. This post examines the operation and uses of fixed cone valves, with a focus on Hilton’s hall-bungar design which set the standard over 100 years ago.
Fixed Cone Valve Operation
Fixed cone valves consist of a truncated conical shape attached to the pressure vessel wall, known as the “fixed cone.” A mating conical shaped closure piece, or “movable cone,” shifts over the fixed cone to seal the opening. Gaskets between the cones maintain the pressure-tight seal.
To open the valve, the movable cone piece shifts laterally along guides to clear the fixed cone opening. Hydraulic or pneumatic actuators provide the linear force to shift the movable cone as needed. An internal sealing arrangement prevents leakage during the shifting operation, which takes only seconds to complete. Once open, full bore flow capacity is maintained comparable to the pipe size.
As pressure increases inside the vessel, it exerts a preloading force between the cones that enhances the seal’s integrity. This self-energizing sealing principle allows fixed cone valves to achieve zero leakage in either flow direction, making them ideal for critical service applications. Proper material selection and lapping the conical surfaces during manufacturing ensures bubble-tight shut-off for the life of the valve.
Established in the late 19th century, Hilton Limited has long been an industry leader in manufacturing high-integrity fixed cone valves with their proprietary “Hall Bunger” design. Named after the engineers who invented the variation, fixed cone hall bunger valve improved upon the fixed cone concept with innovative features that advanced safety and reliability.
Key improvements included filleted transitions between the cones and gasket housing for reduced stress concentrations. Generously radiused sealing surfaces enhance load distribution and improve fatigue performance. Additionally, dynamically aligned actuators ease shifting loads on the cones. These design refinements still serve as the benchmark in fixed cone valve performance today.
Applications Of Fixed Cone Valve
Critical services demand absolute reliability from valves under extreme conditions. Fixed cone valves like Hall-Bunger designs meet these challenges:
- Nuclear Power Plants: Isolation of primary coolant circuits, steam generators, pressurizers and other nuclear process systems require the utmost in safety and leak-tightness.
- Petrochemical Plants: Isolation of high pressure/temperature process streams, distillation columns and other refining units handling hazardous hydrocarbons.
- LNG Terminals: Containment of cryogenic natural gas during transport, storage and regasification require valves proven to handle thermal cycling.
- Industrial Boilers: High integrity isolation of pressurized steam circuits generating power for factories and other facilities.
- Pulp and Paper Mills: Control of high pressure flows carrying wood chips, black liquor and other unit process fluids.
- Offshore Oil Rigs: Valves must operate flawlessly in space-constrained and hazardous offshore environments.
Benefits From Fixed Cone Hall Bunger Valve
Fixed cone valve advantages make them ideal for critical duty isolation applications, including:
- Zero leakage – Self-energizing seal operation provides assured shut-off for the life of the valve.
- Full bore flow – No obstruction when open to minimize pressure drop.
- Strength – Conical sealing surfaces distribute stresses evenly for long fatigue life.
- Reliability – Simple design results in fewer parts prone to wear or malfunction.
- Actuation – External hydraulic actuation removes actuator from high pressure area.
- Maintainability – Cones easily accessible for refurbishment without disrupting piping.
- Material Options – Wide variety of alloys available to match corrosive service conditions.
- Safety – Fully tested and globally certified for use in highly hazardous applications.
When absolute reliability is mission-critical, engineers trust fixed cone valves like Hilton Hall-Bunger designs to safely isolate high-risk systems and protect people, equipment and the environment. Their time-proven sealing principle delivers zero-leak performance that offshore platforms, nuclear plants and critical process industries demand.