| Valve Definition | A quarter-turn rotary valve with a circular disc mounted on a rotating shaft. | The disc regulates or stops fluid flow by rotating inside the valve body, making the design compact and relatively simple. |
| Operating Principle | The disc rotates approximately 90 degrees between the fully closed and fully open positions. | Fast actuation supports efficient isolation and flow control in pipelines, process systems, and utility networks. |
| Primary Functions | Shutoff, isolation, throttling, and basic flow regulation. | A suitable disc and seat design can allow one valve type to serve several common industrial duties. |
| Common Valve Types | Concentric, double-offset, and triple-offset butterfly valves. | Concentric designs are widely used for general service, while offset designs can reduce seat friction and support higher-temperature or more demanding applications. |
| Typical Size Range | Commonly available from approximately DN25 to DN1200 and larger, depending on design and service. | The broad size range makes butterfly valves practical for both building services and large-diameter industrial pipelines. |
| Pressure Capability | Typical industrial designs are available from low-pressure utility service to approximately 16 bar or higher, depending on construction. | The pressure rating must be selected according to the body, disc, shaft, seat, temperature, and applicable design standard. |
| Temperature Capability | Generally from below 0°C to around 120°C for many elastomer-seated designs; higher temperatures are possible with suitable metal-seated designs. | Temperature limits depend primarily on the seat, liner, disc material, fluid, pressure, and sealing arrangement. |
| Flow Path | The disc remains in the flow passage when the valve is open. | This creates some pressure loss compared with a full-bore gate valve, but the streamlined design can still provide efficient flow for many services. |
| Actuation Options | Manual lever, handwheel gearbox, electric actuator, pneumatic actuator, or hydraulic actuator. | Actuator selection depends on valve torque, operating frequency, available utilities, control requirements, and safety conditions. |
| Installation Connection | Wafer, lug, double-flanged, and butt-welded configurations are commonly used. | Connection style affects installation space, maintenance access, pipeline loading, and compatibility with the piping system. |
| Body Materials | Common options include ductile iron, carbon steel, stainless steel, and alloy steel. | Material selection should consider pressure, temperature, corrosion, erosion, external environment, and fluid compatibility. |
| Seat Materials | Common resilient seat materials include EPDM, NBR, and PTFE; metal seats are used for selected high-temperature or severe services. | The seat material strongly influences leakage performance, chemical compatibility, temperature range, and service life. |
| Space Requirement | Usually shorter face-to-face dimensions than many comparable gate or globe valves. | The compact profile reduces installation space and can lower the weight and support requirements of large pipeline assemblies. |
| Weight and Handling | Generally lighter than many gate or globe valves of equivalent nominal size. | Lower weight can simplify transport, lifting, installation, and maintenance, especially in large-diameter systems. |
| Flow Control Performance | Provides useful throttling capability, particularly with suitable control actuators and characterized discs. | For precise control, the valve must be correctly sized and evaluated for cavitation, noise, vibration, and unstable flow conditions. |
| Sealing Performance | Resilient-seated designs can provide tight shutoff when correctly selected, installed, and maintained. | Actual leakage performance depends on valve class, seat condition, differential pressure, temperature, and service media. |
| Typical Applications | Water treatment, cooling water, HVAC, fire protection, chemical processing, power utilities, pulp and paper, and general process piping. | The valve is especially useful for clean liquids, gases, slurries, and other services compatible with the selected materials and seat design. |
| Maintenance Needs | Routine inspection should include actuator operation, shaft condition, seat sealing, flange alignment, fasteners, and signs of corrosion or leakage. | The relatively small number of main components can simplify inspection and reduce maintenance time when access is properly provided. |
| Main Advantages | Compact construction, low weight, quarter-turn operation, broad size availability, and compatibility with automated actuation. | These characteristics can reduce installation costs, support rapid isolation, and make the valve suitable for space-constrained industrial systems. |
| Important Limitations | The disc remains in the flow path, and performance can be affected by abrasive particles, unsuitable throttling, high velocity, or incorrect sizing. | A detailed application review is necessary for severe erosion, high-temperature service, high-pressure drops, slurry concentration, and low-emission requirements. |
| Selection Criteria | Nominal size, pressure class, temperature, fluid properties, flow rate, leakage requirement, materials, connection type, actuator torque, and applicable standards. | Correct selection improves safety, service life, energy efficiency, controllability, and total operating cost. |