Are butterfly valves bidirectional ？

Butterfly Valve is a type of flow control device with the quarter -turn rotational motion , It is used in pipelines to regulate or isolate the flow of fluids ( liquids or gases ) , However, A good quality and performance butterfly valve must equipped a good sealing . Are butterfly valves bidirectional ? Normally we divide the butterfly valve into Concentric butterfly valves and eccentric butterfly valve .
We will discuss about the concentric butterfly valve bidirectional as below :

What is Concentric butterfly valve ?

Concentric butterfly valve know as resilient seated or zero-offset butterfly valves , Their parts include :Valve body , disc ,seat , stem and seal .the structure of concentric butterfly valve is disc and the seat are aligned in the center of the valve , and the shaft or stem is located in the middle of the disc . This means the disc rotates within a soft seat , The seat material can include EPDM , NBR Viton Silicon Teflon Hypalon or elastomer .

How to operate concentric butterfly valve ?

The construction of a butterfly valve is relatively simple , there have three method of actuator for operating :Lever Handle for smaller size , Worm Gear box for Larger valves to make it easier control and Automated operation (include Electric and Pneumatic Actuators )
A butterfly valve operates by rotating a disk (or vane) inside the pipe to control the flow of fluid. The disk is mounted on a stem that passes through the valve body, and turning the stem rotates the disk either to open or close the valve, As the shaft rotates , the disc turns on open or partially open position ,allowing fluid to flow freely .In the closed position , Shaft rotates disc to block the flow entirely and sealing the valve.

Are butterfly valves bidirectional ?

Bidirectional -means can control flow in both directions ,As we talked ,the valves working principle can reach the requirements .So concentric butterfly valves are bidirectional , There have so many advantages to use the concentric butterfly valve .
1 It is more economical than other valve type owing to their simple design and fewer materials needed for construction . The cost saving are mainly realized in large valve sizes .
2 Easy operate , installation and maintenance ,the concenric butterfly valve simplicity makes it easier and faster to install , it can reduce labor cost ,An inherently simple , economic design that consists of few moving parts ,and hence fewer wear points,significantly reduces their maintenance requirements.
3 The lightweight and compact design and a smaller face to face dimension of concentric butterfly valve ,Enable to installed and used in space -limited environments ,They require minimal space compared to other valve types , such as gate or globe valves , and their compactness simplifies both installation and operation , particularly in densely packed systems .
4 Fast acting ,the right-angle (90-degree) rotary design provide with rapid opening and closing. This feature is valuable in applications where a fast response is essential, such as in emergency shut-off systems or processes with precise control requirements. The ability to open and close quickly enhances system responsiveness, making concentric butterfly valves particularly suitable for flow regulation and on/off control in systems demanding a high reaction time.

Finally，the bidirectional butterfly valve with both direction sealing characteristic is due to its elastic sealing structure between the valve seat and butterfly disc , Ensuring consistent sealing regardless of fluid flow direction .This design enhances valve’s practically and reliability in bidirectional fluid control system .