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Ductile Iron 5” PN16 RF Flange Concentric Line Resilient Butterfly Valve

  • Nominal Diameter: 5”(DN125)
  • Bore: Full Bore
  • Nominal Pressure: PN16
  • Material: Ductile Iron
  • Operation: LEVER
  • Design Standard: API609;EN558-1 20 series
  • Test/Inspection: API598
  • End Connection: RF FLANGE
  • Flange standard: EN1092-2,ASME/ANSI B16.5
  • Top Flange: ISO5211

PS: We can manufacture valves to customers’ requirements.

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Product Description:

Concentric Butterfly Valves Collection

Concentric butterfly valves are constructed with a stem travelling along the midline of the valve disk and lack any offsets. With a full diameter structure, WKT as an experienced industrial valve company, our concentric butterfly valves reduce flow resistance and ensure fluids smoothly pass through the valves.
As they are made with fewer components, concentric valves are easier to set up due to their lightweight frame and are more affordable variants.


  • Bubble-Tight, full rated bi-directional shutoff
  • One-piece body
  • Integral ISO mounting
  • High performance resilient seat
  • Light weight, low cost and maintenance free
  • Position Indicator

Main Features of the Product

  • Provide a variety of seat and disc materials to suit a variety of process applications
  • The wide flange face seal area provides a tight seal and eliminates the need for flange gaskets
  • It can close quickly, but less support required than a heavier ball valve
  • Integral stainless steel stem ensures stability and reliable disc positioning.


  • Water and wastewater treatment plants.
  • HVAC systems for flow control of water or air.
  • Chemical processing industries.
  • Power generation plants for fluid regulation.
  • General industrial processes requiring reliable flow control.


The valve operates using a simple quarter-turn mechanism. It can be manually operated with a handwheel or automated using methods such as worm gears, electric actuators, pneumatic actuators, or hydraulic actuators.

Size Range

The valve comes in various sizes, typically ranging from 1″ to 10″. The size range may vary based on specific product offerings.

Pressure Ratings

With common ranges being 150LB–600LB or PN10–PN64. The pressure rating indicates the maximum pressure the valve can handle.


  • Ductile Iron Construction: Offers enhanced strength and durability.
  • RF Flange: Provides effective sealing for reliable performance.
    Concentric Line Design: Ensures efficient flow control.
  • Resilient Seat: Offers a reliable seal and flexibility in various applications.
  • Versatility: Suitable for both manual and automated operation.
    Cost-Effective: Provides a cost-effective solution for flow control needs.
  • Compact Design: Suitable for installations with space constraints.
  • Wide Range of Applications: Suitable for various fluid-handling systems in different industries.


1. Ductile Iron: The valve body is made of ductile iron. Ductile iron, also known as nodular cast iron or spheroidal graphite iron, is a type of cast iron that exhibits enhanced strength and ductility. It is known for its resistance to fracture and is commonly used in various industrial applications.

2. RF Flange: “RF” typically stands for Raised Face, indicating the type of flange facing. RF flanges have a raised surface around the bolt holes, providing a sealing surface when compressed against a flat gasket for a secure and tight seal.

3. Concentric Design: The term “concentric” refers to the centering of the valve stem and disc within the valve body. In concentric butterfly valves, the disc’s center is aligned with the center of the valve body bore.

4. Resilient Seat: A resilient seated butterfly valve is characterized by a stem that is bored into the disk and attached to the bottom of the valve. Most of the time, the seats of this kind of valve is made of rubber, hence, the term resilient. As such, the disc relies on the high contact capability of the seat and the seat for tight shut-off. With this kind of design, the seat-to-seal contact begins at about 85-degree turn. Resilient seated butterfly valves are made of a one-piece. This increases the strength of the valve as well as reduce its weight. The rubber-back seat makes it easy to install even when the butterfly valve is outdoors. Because of the nature of the material, it has a reliable sealing capacity.
The seats of the butterfly valve can be categorized into two. These are the soft materials and the metal-seated butterfly valve. The resilient seat butterfly valve belongs to the former. Used for non-critical applications, such butterfly seats can be made from EPDM (ethylene propylene diene terpolymer), VITON, and acrylonitrile-butadiene rubber.

5. Butterfly Disc: The butterfly disc is a flat, circular plate that rotates around the valve stem to control the flow of fluid. In the case of resilient butterfly valves, the disc typically has a soft, resilient lining that ensures a reliable seal with the seat.

Why do You Need China Concentric Butterfly Valves

Concentric butterfly valves have a simple structure that consists of fewer components compared to other valves, making them easier to operate and maintain. With a full-diameter structure, the valve regulates flow and ensures the smooth passage of fluids.
Here are some advantages of concentric butterfly valves.
They take up small space compared to other valves

  • Due to their compact and lightweight form, the installation, maintenance, and labor costs are reduced
  • As the seat is constructed in the form of a sleeve or cartridge inside the body, the media flowing through the valve will not contact the body
  • Concentric butterfly valves are easier to set up
  • These valves require less support to close than industrial ball valves
  • Various seat and disc materials can be used to suit different industrial applications

China Concentric Butterfly Valves Sourcing Guide

Before sourcing from concentric butterfly valve supplier, some common factors need to be considered so you could choose the right valves for your business.

What are Concentric Butterfly Valves?

A concentric butterfly valve, also called a zero offset butterfly valve, is a flow regulatory mechanism that uses a rotary disc to control fluid flow. In this design, the stem passes through the middle line of the disc in the center of the pipe bore, and the seat is inside the diameter of the valve body.

Types Of Concentric Butterfly Valves Available In Skyvalve

Skyvalve concentric butterfly valve factory manufactures different types of valves, including Wafer-type concentric butterfly valve, Lug-Type concentric butterfly valve, flanged concentri butterfly valve and other types.

  • Wafer Type Concentric Butterfly Valve
Wafer Type Concentric Butterfly Valve
The wafer-type concentric butterfly valve ensures tight sealing protection against two-directional pressure differentials. It’s mostly used for one-directional flow devices. This valve uses a tight-fitting cap, such as o-rings, to seal the valve face.












  • Lug Type Concentric Butterfly Valve
Lug Type Concentric Butterfly Valve
A lug-type butterfly valve is identical to a 3-piece ball valve, where you can replace one side of the pipeline without affecting the other. This design is achieved using threaded inserts, flanges, and two sets of lugs, one for each flange.
  • Double Flanged Concentric Butterfly Valve
Double Flanged Concentric Butterfly Valve
This type of butterfly valve has a flange at both valve ends, which are attached to the pipe flanges. This design is commonly used for large butterfly valve sizes.
  • Butt-welded Concentric Butterfly Valve
Butt welded Concentric Butterfly Valve
Welded butterfly valves are used for high-pressure systems as direct welding secures the connection. In this design, the angled pipe end and straight valve ends are welded together, forming a butt-welded connection. They are commonly used for small butterfly valve sizes.

Construction Of the Concentric Butterfly Valve

Most concentric butterfly valves use an elastomeric seat, against which sealing occurs. This seat design ensures the o-rings are not deformed.
The valve body is constructed in various ways. For example, the wafer-type design fits between two pipeline flanges, and the lug-type design is held between two pipe flanges by bolts.

For the construction and connection of the stem and disc, the disc is bored to receive the stem. This can be done in two ways: the disc is either bored through and secured to the stem using nuts and bolts or the disc is first bored and the upper stem bore is shaped to fit a square or hex-shape.
In designing, concentric butterfly valve suppliers should consider the properties of the media that the valve control after installation. Depending on its application, concentric butterfly valve manufacturers can develop valves in a wide-ranging series of standard and custom sizes to offer options to clients.

How Does a Concentric Butterfly Valve Work?

The valve body, seal, disc, and stem make up the concentric butterfly valve. The disc is connected to an actuator or handle outside the valve, which rotates it on a vertical or horizontal axis.
The valve is fully open when the disc is rotated parallel to the piping run and the valve is shut when the disc is rotated to a perpendicular position. For throttling or flow regulation purposes, a handle-locking device is used to keep the valve in an intermediate position.

Concentric Butterfly Valve vs. Eccentric Butterfly Valve

While a concentric butterfly valve disc is simple, an eccentric butterfly valve disc requires several components, such as a sealing ring and holding ring.
In the concentric valve, the disc touches the rubber seat directly, but in the eccentric valve, a laminated disc seals the metal body seat.
The seat of a concentric butterfly valve is soft while an eccentric butterfly valve seat is made of metal.
The pressure limit of a concentric butterfly valve is 150LB/PN25, but an eccentric butterfly valve can handle up to 600LB/PN100 of pressure.
Due to its construction, the concentric rubber seat cannot handle high temperatures, but an eccentric/double offset butterfly valve can handle high temperatures as they have a metal seal design.

The Lowest-Cost Strategy Is To Choose Reliable TIANYU Valves.

TIANYU Valve, with its experienced specialists, specializes in manufacturing industrial valves and provides technical support and one-stop solutions for the global market.

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