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Flange Ball Valve: Complete Guide

July 19, 2020

A flanged ball valve is a type of ball valve with flanged connections, which are commonly used due to their easy installation and excellent sealing performance, making them the most common type of connection for ball valves.

The main components of a flanged ball valve include the valve body/cover, ball, stem, and seat.

Valve Body/Cover: The valve body and cover form the shell of the ball valve and are important pressure-bearing parts. The connection ends of the body and cover are flanged surfaces used to connect to pipelines. Sufficient strength of the body and cover is required to prevent external leakage or serious safety accidents.

Ball: The ball is typically solid to provide sufficient strength to withstand fluid pressure. The roundness and surface finish of the ball are crucial factors affecting the sealing of the flanged ball valve.

Stem: The stem connects the ball and the driving device and is usually made of high-strength materials such as F6a, 17-4PH, XM19.

Seat: The seat is an important sealing component and comes in two types: soft-seated and hard-seated. Soft-seated valves offer high sealing performance but cannot withstand high temperatures or fluids with particulate impurities. Hard-seated valves may have slightly inferior sealing performance but can be used in high-temperature conditions and with fluids containing impurities.

Working Principle

Flanged ball valves control the flow of fluid by opening and closing the ball. When the direction of the ball hole aligns with the flow passage, the valve is in the open position, allowing the medium to flow smoothly. By rotating the ball 90 degrees via the stem, and under the pressure of the pipeline fluid, the ball tightly seals against the valve seat, effectively cutting off the flow of fluid.

 

Flange Types

  • Raised Face (RF): RF flanges have a raised surface around the bolt holes, providing a seal contact area.
  • Flat Face (FF): FF flanges have a flat surface without any raised areas. They require gaskets to create a seal
  • Ring Type Joint (RTJ): RTJ flanges have grooves machined into their faces, where a metal ring gasket is placed to create a tight seal.
  • Groove flanges: They have a groove machined into their surface where an O-ring or gasket is seated to create a seal.

Flange Standard

  • EN 1092: European standard for flanges, it covers flanges and their joints intended to be used in European pressure equipment applications.
  • ANSI B16.47: This standard covers large diameter steel flanges from NPS 26 through NPS 60. It includes series A (MSS SP44) and series B (API 605) flanges.
  • JIS B2220: Japanese Industrial Standard for steel pipe flanges.
  • DIN 2501: German standard for flanges, it covers flat flanges for welding (plate flanges) and flanges with raised faces

Flange Ball Valve Types

 

Side entry high temperature ball valve Side enWelded body high temperature ball valvetry high temperature ball valve Three-way lockable ball valve Full Welded Ball Valve
Side Entry Flange Ball Valve Trunnion Mounted Flange Ball Valve 3 Way Flanged Ball Valve Full Weld Flange Ball Valve

 

Two-piece high temperature ball valve
Tope Entry Flange Ball Valve Floating Flange Ball Valve

Drive Mechanisms for Flanged Ball Valves

The quarter-turn rotation of flanged end ball valves is achieved through various driving mechanisms, including Lever, Gear Unit, Hydraulic, Pneumatic, or Electric actuators.

Gear Unit

Gear units facilitate easier operation of valves, with clockwise operation for closure and anti-clockwise for opening. A location indicator on the gear panel shows the valve’s position.

Electric Actuator

These provide multi-turn output and can be installed directly on the valve or gear unit. They power the gear assembly to rotate the shaft. Electrically actuated valves have a manual control option through a declutching system.

Pneumatic / Hydraulic Actuator

These actuators are often mounted directly to the valve without a gear assembly. Strict adherence to guidelines in the actuator manual is advised.

 

Side entry API 6D ball valve

Handling & Storage

Handling

  • Valves must be properly supported and secured during movement to prevent damage to the valve, property, or harm to personnel.
  • Avoid dragging valves on the ground during transportation, maintaining a minimum height from the ground.
  • Do not sling valves around the valve port for transportation.
  • Crane wires should not be slung around the actuator/gear unit to avoid placing load on it.
  • Valves should not be handled with the handwheel fixed to the gear unit. Remove the handwheel before handling and transporting.

Storage

  • Valves must be stored in a protected, well-ventilated environment free of dust and humidity.
  • End protectors should remain in place until the valve is installed to prevent damage from dry pollutants.
  • Valves should be kept at a temperature higher than the dew point to prevent water droplet accumulation.
  • Valves should not be placed directly on the floor but on a wooden pallet to maintain minimum height.
  • Care should be taken to avoid damaging any extended portions of the adaptor, gear unit, or actuator during storage.

Usage Instructions

  • Assembly and disassembly should only be done after confirming that upstream and downstream pipes are depressurized.
  • Non-metal parts should not be soaked for prolonged periods in cleaning agents.
  • Bolts on the flange must be tightened symmetrically, gradually, and evenly.
  • Cleaning agents must be compatible with all valve components and working media.
  • Lubricate parts with appropriate grease before assembly.

Three-way fire safe ball valve

Installation of Flange Ball Valve

  • Ensure proper alignment of front and rear pipes, with parallel sealing surfaces of flanges.
  • Purge pipelines before and after valve installation to remove impurities.
  • Confirm valve integrity and functionality before installation.
  • Properly install gaskets between valve flange and pipeline flange.
  • Tighten flange bolts symmetrically and evenly.

Maintenance & Repair

Precautions for Repair and Maintenance

  • Maintain harmonious temperature/pressure ratios and reasonable corrosion data.
  • Ensure line pressure is released and valve is left open before servicing.
  • Disconnect power or air supply from driving mechanisms before repair.
  • Disconnect actuator from bracket before maintenance.

Disassembly

  • Keep valve in half-open position to flush out any dangerous substances.
  • Close valve and remove connecting bolts and nuts on flanges.
  • Disassemble drive device, actuator, and other components in order.
  • Remove body cover and valve seat.

Assembly

  • Clean and inspect all removed parts.
  • Replace seals, valve seats, and gaskets with spare parts if necessary.
  • Assemble components in reverse order of disassembly.
  • Tighten flange connection bolts and stem nuts to the specified torque.
  • Perform pressure seal and performance tests before reinstalling the pipeline.
  • Ensure packing is properly locked to prevent leakage.

Conclusion

This article provides a detailed overview of flanged ball valves, which are our primary product. If you have any questions or need further information, please feel free to contact us at any time. We are here to assist you with your inquiries and provide the best solutions for your needs.

 

 

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