Concentric Butterfly Valve

The concentric butterfly valve is a standard or a general use butterfly valve. The shaft is located in the center of the disc. During opening or closing, some parts of the disc are always in-contact or rubbing the seat.

This arrangement will make the seat experience friction each time the valve is operating. In a typical application, this concentric butterfly valve is limited to class 150 due to its seat design.

ZECO Valve is a professional butterfly valve manufacturer in China and the butterfly valve is the main product series of ZECO valve. The rubber-lined concentric butterfly valve is widely used in various kinds of operating conditions because compare to other valves it cost lower and the required installation space is smaller. Centerline butterfly valves are usually used in the water supply pipeline.

Types of Centerline Butterfly Valve

Based on the connection there are different types of concentric butterfly valves.

• Wafer type ends.
• Lug type ends.
• Both flanged ends.
• Butt-welded types end

Wafer Type: The wafer type of the butterfly valves was built to keep a tight sealing, protecting against bi-directional pressure differentials, to prevent any backflow in devices that were built for uni-directional flow. This is done by the use of a tightly fitted cap, such as an O-ring, or gasket, precisely machined, along with a smooth valve face on the downstream and upstream parts of the valve.

Lug Type: The lug body type of the butterfly valve design is identical to the 3-piece ball valve in which one end of the pipeline can be replaced without impacting the other side of the valve. This can be achieved with threaded inserts, flanges, and two sets of lugs (bolts) that do not use nuts so each flange has its bolts. It is also important to remember that you do not need to shut down the whole device to inspect, clean, repair, or replace the lug butterfly valve.

Flanged End Type: The flanged end type butterfly valve has a flange at both ends of the valve to be attached with pipe flanges. This type of end connection is used for the very large size of the butterfly valve.

Welded End Type: The welded end type butterfly valve is used where the system is under very high pressure. These types are generally used for small-size butterfly valves.

Applications of Concentric Butterfly Valve

Concentric butterfly valves employ soft sealing material due to which it can only be used in basic (water & wastewater treatment plant), special liquid (chemicals, abrasive liquids, etc), and gases for up to 200 psi and 400degree F.

• Water treatment.
• Water Distribution.
• Water Transmission.
• Aeration System.
• Fire Protection, etc.

What is a butterfly valve?

A butterfly valve is a kind of adjusting valve of simple body construction and can be used for open/close or flow control purposes for the low-pressure pipeline.

The shutter for the butterfly valve is a round plate, disc open/closed center to a valve stem which is the center line of the valve body as well.

Butterfly valves can be used in various kinds of applications like water, wastewater, seawater, air, mud, oil and corrosive service, etc. In many kinds of low-pressure pipelines of shutoff/flow adjusting applications, a butterfly valve can be used to replace a gate valve, globe valve, or ball valve which would save the cost for the user.

A butterfly valve is available for quick opening/close, is easy to operate, has low flow resistance, and is suitable for high-frequency open/close. ZECO centerline butterfly valve is bi-directional for seat sealing and can be installed in either direction of the pipeline, sealing performance is reliable and the rubber seat is replaceable.

Butterfly Valve Selection Guidance

Butterfly valve, especially centerline butterfly valve is usually made of a ductile iron body, which means the valve is suitable for low-pressure pipelines but not suitable for high-pressure pipelines. To choose a suitable butterfly valve, we need to consider the below factors:

Size and pressure, due to its advantage of simple construction, butterfly valves are available in big sizes till 120″ or even much bigger. It should be noticed that the bigger the butterfly valve size is, the lower pressure it can bear. So, a big-size butterfly valve can only be considered for low-pressure pipelines.

The most commonly used material for centerline butterfly valve body is ductile iron, carbon steel may also be used as body material for some specific applications.

Centerline butterfly valve don”t have individual seat, the seat is lined on the internal body. While choosing seat material for a concentric butterfly valve, we should consider the temperature, fluid medium, and pressure, commonly used seat materials are EPDM, NBR, NR, etc.

The most important part of choosing a butterfly valve is to choose its disc material, for example, water and wastewater can use a ductile iron disc with nickel plated, seawater can use al-bronze as disc material, etc.

The stem of the centerline butterfly valve don”t have contact with the fluid, so we don”t have to consider the corrosion issue, so normal martensitic stainless steel is enough.

The concentric butterfly valve is characterized by the stem center, disc center, and body center in the same position. The centric butterfly valve of ZECO has a flanged concentric butterfly valve, Wafer concentric butterfly valve, and so on. A flanged butterfly valve is used in various service and drain lines as truncation and regulating equipment. Wafer concentric butterfly valve can be used as adjusting and intercepting equipment on non-corrosive gas, liquid, semiliquid, solid powder tube, and vessels. The flexible flanged concentric butterfly valve is suitable for intercepting and adjusting the general corrosive, non-corrosive gas, liquid, semifluid, and solid powder media, and also can be used as replacement products for old pipeline renovation, maintenance, and matching valves. As butterfly valve manufacturer in China, we will be more strict with the quality, on the one hand, to make the product in use can have the repair rate convenience simple, on the one hand, the hope to the quality to win customer satisfaction are abundant brand can be set up in the field of global water use butterfly valves, so we would like to to the attitude of benchmarking to establish the brand, to make our products.