Cone Valves

Cone valves are quarter-turn control valves that use a conical plug to regulate flow by rotating within a cylindrical seat, creating a variable orifice opening. The conical design provides excellent throttling characteristics and maintains linear flow control across a wide range of positions. These valves typically achieve Cv values ranging from 0.1 to 15,000 depending on size, with 2-12 inch diameters being most common in municipal applications. While cone valves offer superior control accuracy and reduced cavitation compared to globe valves, their higher initial cost and complex internal geometry requiring specialized maintenance limit adoption in smaller municipal facilities.

• Raw Water Intake Control (2-20 MGD plants): Cone valves regulate flow from intake structures or wells, connecting between raw water pumps and treatment trains. Selected for tight shutoff against debris and ability to throttle flow without cavitation damage. Typical installation between 12-36 inch ductile iron mains.

• Clarifier Effluent Control: Used on clarifier outlet channels (8-48 inch) to balance flow distribution and provide emergency isolation. The streamlined flow path prevents solids accumulation that would clog butterfly valves. Critical for maintaining consistent hydraulic loading across multiple clarifier units.

• Filter Backwash Lines: Control high-velocity backwash water (4-8 fps) in 12-24 inch steel piping. Cone design handles erosive conditions and frequent cycling better than gate valves. Provides precise flow control during filter-to-waste operations.

• Sludge Line Isolation: Installed on primary and secondary sludge withdrawal lines (6-16 inch) where complete shutoff is essential. The cone's wiping action clears solids that would prevent proper seating of other valve types.

Daily Operations: Operators monitor valve position indicators and verify proper seating through downstream pressure readings. Electric actuators require checking motor current draw during operation cycles. Manual valves need periodic exercising (monthly) to prevent seizing, requiring 2-person operation for valves above 16 inches due to high operating torques.

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Maintenance: Annual inspection includes packing adjustment and seat inspection. Cone removal requires confined space entry procedures and fall protection when accessing vault installations. Maintenance staff need hydraulic tools for larger actuators and precision measuring equipment for seat concentricity checks. Typical rebuild intervals: 8-12 years for manual units, 5-8 years for automated systems.

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Troubleshooting: External leakage indicates packing failure (replace annually). Internal leakage shows as downstream pressure when valve is closed - often caused by debris on seat or worn cone surface. Actuator hunting indicates control signal issues or mechanical binding. Properly maintained cone valves achieve 25-30 year service life with two major rebuilds.

• Cone Assembly: Precision-machined stainless steel or bronze cone provides sealing surface. Municipal sizes typically 4-48 inches. Selection based on pressure rating (150-300 psi) and corrosion resistance requirements for specific water chemistry.

• Body Casting: Ductile iron or carbon steel body with flanged or mechanical joint ends. Wall thickness varies by size (AWWA C515 standards). Epoxy lining standard for potable water service, with optional rubber lining for wastewater applications.

• Actuator System: Manual gear operators for smaller valves (4-12 inch), electric or hydraulic actuators for larger sizes. Torque requirements range from 200 ft-lbs (6-inch) to 8,000 ft-lbs (36-inch). Position indication and limit switches standard on automated units.

• Seat Ring: Replaceable bronze or stainless steel seat ring provides sealing surface. Field-replaceable design allows maintenance without valve removal. Hardness differential between cone and seat prevents galling during operation.

• Flow Velocity Control: Velocity range: 2-8 fps (optimal 4-6 fps to minimize head loss), Flow rates: 0.1-25 MGD per valve for municipal applications, Pipe sizes: 6"-72" diameter (most common 12"-48")

• Pressure Requirements: Working pressure: 150-300 psi (ANSI Class 150/300 flanged), Pressure drop: Typically 2-15 psi at design flow, Maximum differential pressure: 200 psi across valve

• Control Accuracy: Flow control accuracy: ±2-5% of setpoint, Rangeability: 20:1 to 50:1 turndown ratio, Response time: 15-60 seconds for 90% travel

• Physical Specifications: Valve body materials: Ductile iron, carbon steel, or stainless steel, Seat materials: EPDM, Buna-N, or Viton elastomers, Actuator sizing: Based on required torque (typically 500-5000 ft-lbs), Temperature range: 32°F-180°F for municipal water applications

• Loading Considerations: Cv values: Range from 50-15,000 depending on size, Minimum controllable flow: 5-10% of maximum rated capacity

• What is the required flow control accuracy and rangeability? Standard cone valves provide ±5% accuracy with 20:1 turndown, while precision models achieve ±2% with 50:1 turndown. Inadequate rangeability forces multiple valve installations or poor control at low flows. Need: process flow variations, minimum/maximum flow requirements, and control system specifications.

• What differential pressure will the valve experience during operation? Cone valves handle up to 200 psi differential, but exceeding this causes seat damage and control instability. High-pressure drops (>50 psi) may require pressure-reducing valve stations upstream. Need: system head curves, pump characteristics, and downstream pressure requirements.

• Should the valve be fail-open or fail-closed, and what backup power is required? Municipal safety requires defining failure mode - treatment processes typically fail-open, while distribution systems fail-closed. Electric actuators need battery backup (4-8 hours typical), pneumatic systems require air receivers. Wrong choice causes process upsets or safety hazards. Need: process criticality analysis and emergency response procedures.

• What materials are required for the specific water chemistry? Chlorinated water requires chlorine-resistant elastomers (EPDM/Viton vs. Buna-N), while aggressive water needs upgraded body materials. Wrong materials cause premature failure within 2-5 years versus 15-20 year design life. Need: water quality analysis including chlorine residuals, pH, and corrosivity indices.

• Primary: Division 40-05-23 - General-Duty Valves for Water Utilities

• Secondary applications: Division 46-07-13 (Water Utility SCADA Instru

• Material/Equipment Verification: Verify elastomer compatibility with municipal water chemistry (chlorine, pH ranges), Confirm pressure ratings match system operating pressures plus surge allowances, Check temperature ratings for seasonal variations

• Installation Requirements: Minimum 5D upstream, 2D downstream straight pipe runs, Adequate clearance for sleeve removal/replacement, Support piping independently - valve cannot support pipe loads

• Field Challenges: Sleeve damage during shipping/handling, Improper bolt torquing causing uneven compression, Air entrapment in pneumatic actuators

• Coordination Issues: Lead times typically 8-12 weeks for municipal specifications, Coordinate electrical connections for automated versions early

• Red Valve Company - Series 5200 Pinch Valves (technically elastomer-lined, cone-valve function)

• Plast-O-Matic Valves - Series CKM True Union Ball Valves with cone seats

• APCO (DeZURIK) - Model 140 Combination Air Valves with cone disc assemblies

• Val-Matic Valve - Model 210 Air Release Valves featuring cone-style closures

• Butterfly Valves - Lower cost ($2,000 vs $4,000+ for cone valves), better for frequent operation, but poor throttling control and higher pressure drop.

• Ball Valves - Superior shutoff capability, longer service life, but 2-3x higher cost and limited large diameter availability.

• Gate Valves - Traditional municipal standard, lowest cost for isolation service, but poor throttling performance and prone to seat damage in dirty water applications.

Establish relationships with local manufacturer representatives early - they provide valuable field support during commissioning. Many municipalities negotiate annual service contracts including spare sleeve inventory. Cost-saving opportunity: specify standard port sizes rather than custom diameters to reduce lead times and costs by 15-20%. Always order spare sleeves with initial equipment - replacement sleeves often have 6+ week lead times that can shut down critical processes.