A butterfly valve is a type of valve that utilizes a disc-shaped closure element to rotate back and forth approximately 90 degrees in order to open, close, or regulate the flow of a medium. Butterfly valves are characterized not only by their simple structure, compact size, light weight, minimal material consumption, small installation footprint, low operating torque, and ease and speed of operation, but also by their simultaneous possession of excellent flow regulation capabilities and reliable shut-off sealing characteristics; consequently, they have emerged as one of the fastest-developing valve types over the past decade or so. The application of butterfly valves is extremely widespread. The variety and volume of their usage continue to expand, trending toward applications involving high temperatures, high pressures, large diameters, superior sealing capabilities, extended service life, excellent regulation characteristics, and multi-functional integration within a single valve unit. Furthermore, their reliability and other performance metrics have attained a high level of sophistication.
The performance of butterfly valves has been significantly enhanced through the application of synthetic rubbers engineered to resist chemical corrosion. Synthetic rubbers possess a host of advantageous characteristics-including corrosion resistance, erosion resistance, dimensional stability, excellent resilience, ease of molding, and low cost-and can be specifically selected based on varying performance requirements to precisely match the operating conditions and service environments of the butterfly valves.
Furthermore, polytetrafluoroethylene (PTFE) offers strong corrosion resistance, stable performance, resistance to aging, a low coefficient of friction, ease of molding, and dimensional stability. Moreover, its comprehensive performance can be further optimized-yielding sealing materials for butterfly valves with enhanced strength and even lower friction coefficients-by incorporating appropriate fillers and additives. This capability effectively overcomes the inherent limitations associated with synthetic rubbers; consequently, polymeric materials-exemplified by PTFE-along with their modified, filler-enhanced derivatives, have found extensive application in butterfly valves. This development has led to a further elevation of butterfly valve performance, enabling the manufacture of valves capable of operating across wider temperature and pressure ranges, delivering reliable sealing performance, and offering significantly extended service lives.
In order to satisfy the rigorous operational demands of industrial applications-including those involving extreme high and low temperatures, severe erosion, and requirements for extended service life-metal-seated butterfly valves have undergone substantial development and advancement. With the application of high-strength alloy materials-featuring resistance to extreme temperatures (both high and low), severe corrosion, and intense erosion-in butterfly valves, metal-seated butterfly valves have found widespread application in industrial sectors characterized by extreme temperatures, severe erosion, and requirements for long service life. This has led to the emergence of butterfly valves with large nominal diameters (9–750 mm), high pressure ratings (up to 42.0 MPa), and wide operating temperature ranges (-196°C to 606°C), thereby elevating butterfly valve technology to an entirely new level.
When fully open, butterfly valves exhibit minimal flow resistance. When positioned between approximately 15° and 70° of opening, they enable sensitive and precise flow control; consequently, butterfly valves are widely utilized in applications involving the regulation of flow in large-diameter pipelines.
Due to the inherent wiping action of the disc as it moves, most butterfly valves are suitable for use with media containing suspended solid particles. Depending on the strength and durability of the sealing components, they can also be employed with powdery or granular media.
Butterfly valves are well-suited for flow regulation applications. However, because the pressure loss across a butterfly valve within a pipeline is relatively high-approximately three times that of a gate valve-the potential impact of this pressure loss on the overall pipeline system must be carefully evaluated when selecting a valve. Furthermore, consideration must be given to the structural strength of the valve disc to ensure it can withstand the pressure exerted by the pipeline media when the valve is in the closed position. Additionally, for valves utilizing elastic seats, the temperature limitations of the seat material under high-temperature operating conditions must be strictly observed.
Butterfly valves are characterized by their compact structural length and low overall height, rapid opening and closing speeds, and excellent fluid control characteristics. The fundamental structural design of the butterfly valve makes it particularly well-suited for the manufacture of large-diameter valves. When a butterfly valve is intended for flow control purposes, the critical factor is the correct selection of the valve's specifications and type to ensure it operates both appropriately and effectively.
Generally, butterfly valves are recommended for applications involving throttling, flow regulation, or media containing slurry, particularly where requirements include a short structural length, rapid opening and closing speeds, and low-pressure shut-off capabilities (i.e., across small differential pressures). They may also be selected for applications involving two-position control, pipelines with reduced diameters, low-noise requirements, conditions prone to cavitation or vaporization, situations where minor leakage to the atmosphere is permissible, or when handling abrasive media. Furthermore, butterfly valves are utilized for throttling and regulation under specific, demanding operating conditions-such as those requiring exceptionally tight sealing, involving severe wear, or operating at extremely low (cryogenic) temperatures.
