What is a wafer type butterfly valve used for?
A wafer-type butterfly valve is connected between two pipe flanges using double-ended bolts. Its compact structure makes it suitable for applications with limited space or short pipe spacing.
Classification:
By sealing method: Divided into resilient seal and metal seal. Resilient seal valves have sealing rings that are embedded in the valve body or attached to the perimeter of the butterfly plate; metal seal valves have a long service life but are difficult to achieve a complete seal, although they can withstand higher operating temperatures.
By structural form: Includes centerline, double eccentric, and triple eccentric types. The triple eccentric structure achieves frictionless transmission through eccentric design, extending valve life and providing bidirectional sealing.
Structural Features
Main components: Composed of valve body, valve plate, valve stem, sealing components, etc. Some high-performance valves use a double or triple eccentric structure with a special oblique conical elliptical seal design.
Design Advantages:
Compact structure: Small size and light weight, easy to install and maintain.
Quick opening and closing: Only a 90° rotation is needed to complete full opening or full closing operation, simplifying operation.
Low fluid resistance: In the fully open state, the thickness of the butterfly plate is the only resistance to the medium flowing through the valve body, resulting in low pressure drop and excellent flow control characteristics.
Reliable sealing: High-performance valves employ a triple eccentric structure and a metal hard seal to achieve a zero-leakage sealing effect.
Working Principle
Opening and closing control: The valve stem is rotated by a manual operating device (such as a handle or worm gear box) or a drive device (such as electric or pneumatic), which in turn drives the valve plate to rotate 0°~90° around its axis within the valve body.
Sealing mechanism:
Elastic seal: Sealing is achieved through the elastic deformation of the sealing ring, suitable for low-temperature and low-pressure conditions.
Metal seal: Sealing is achieved through the hard contact between the metal valve seat and the butterfly plate, suitable for high-temperature, high-pressure, or corrosive media.
Technical parameters
Nominal diameter: Common specifications are DN25~DN1000, with some products reaching DN1200.
Nominal pressure: Generally, pressure ratings include PN1.0, PN1.6, and PN2.5.
Applicable Temperature: Depends on the sealing material and valve body material. Resilient-seal valves are suitable for temperatures ranging from -30℃ to 130℃, while metal-seal valves can withstand higher temperatures.
Applicable Media: Includes water, acid and alkali solutions, corrosive fluids, steam, air, and coal gas.
Applications
Petrochemical Industry: Used for media control in crude oil transportation and refining units, adaptable to high-temperature, high-pressure, and highly corrosive environments.
Municipal Water Supply and Drainage: Used for flow regulation in main pipeline networks, zoned water supply control, and inlet/outlet shut-off of pump stations, especially suitable for large-diameter applications.
Power Industry: Used for control of steam turbine circulating water systems and boiler drain pipes, adaptable to high-temperature and high-pressure steam conditions.
Metallurgical Industry: Used for control of blast furnace cooling water systems and coal gas pipelines, adaptable to high-temperature, abrasive, and corrosive environments.
Water Treatment Industry: Used for media control in sewage pipelines and aeration tank inlets/outlets, adaptable to resistance to sewage impurities and sludge corrosion.
Advantages and Disadvantages Analysis
Advantages:
Simple Structure: Fewer parts, easy to install and maintain.
Easy Operation: Low opening and closing torque, effortless operation.
Good Sealing: High-performance valves can achieve zero-leakage sealing, ensuring no fluid leakage.
Wide Applicability: Can be used to control the flow rate of gases, liquids, and various corrosive media.
Outstanding Economic Efficiency: The cost of a valve of the same diameter is approximately 1/2 that of a gate valve and 1/3 that of a ball valve, especially significant in large-diameter applications.
Disadvantages:
Limited Adjustment Precision: Prone to vibration and noise when throttling at small openings, unsuitable for precise flow regulation.
Prone to Jamming by Particulate Media: Expansion joint gaps are easily blocked by slurry and fibrous impurities, requiring additional anti-jamming structures.
Weak Water Hammer Resistance: Prone to water hammer effects during rapid opening and closing, requiring the addition of slow-closing devices, increasing system complexity.
Wafer Type Butterfly Valve drawning
