What is Telescopic Flange Butterfly Valve
The flange telescopic butterfly valve is a butterfly valve that integrates flange connection and telescopic function. Its core design is to compensate for the axial displacement of the pipeline caused by thermal expansion and contraction, installation errors or medium pressure fluctuations through the telescopic flange structure, while using the rotation of the butterfly plate to realize the opening and closing and regulation of the fluid.
Structural Features
Flanged Connection Design: The valve body has flanges at both ends, which are directly connected to the pipe flanges via bolts. This ensures reliable sealing and convenient installation, making it particularly suitable for high-pressure and large-diameter applications. The flange material is typically cast iron, carbon steel, or stainless steel, matching the valve body material to ensure overall strength and corrosion resistance.
Expansion/Retraction Structure:
Sleeve-type Expansion/Retraction: The valve body consists of two sleeves in the middle. The inner sleeve slides within the outer sleeve, achieving dynamic sealing through sealing rings (such as O-rings or lip seals).
Belled Pipe-type Expansion/Retraction: A metal bellows connects both ends of the valve body. Displacement is absorbed through the elastic deformation of the bellows, suitable for high-temperature and high-pressure environments.
Limiting and Locking Devices: Limiting bolts or blocks are provided at both ends of the expansion sleeve to prevent excessive expansion and contraction that could lead to sealing failure. Some models are equipped with locking rings to fix the sleeve position during installation and prevent displacement changes during operation.
Butterfly Plate and Sealing System:
Soft Seal: Elastic materials such as nitrile rubber and EPDM provide good sealing performance but have low temperature resistance (≤120℃). Hard Seal: The valve seat and butterfly plate sealing surfaces are overlaid with stainless steel or cobalt-based hard alloy, providing high temperature and pressure resistance and a long service life.
Composite Seal: A combination of soft and hard layered metal sheets (such as a flexible graphite plate combined with a stainless steel plate), combining elasticity and wear resistance.
Butterfly Plate Design: A circular or elliptical thin plate that rotates around its own axis (0°~90°) to control flow. Materials include stainless steel, copper, nylon, or rubber coating, adaptable to different media.
Sealing Forms:
Eccentric Structure: Double eccentric design reduces friction and extends service life; triple eccentric structure completely eliminates friction, suitable for ultra-high temperature and high pressure conditions.
Functional Advantages
Pipeline Stress Compensation: Absorbs axial displacement caused by temperature changes, media pressure fluctuations, or installation errors, reducing the risk of pipeline deformation and preventing rupture or leakage. The expansion/contraction is typically 1%~3% of the nominal pipe diameter, meeting the needs of most operating conditions.
Highly Efficient Fluid Control: A 90° rotation of the butterfly plate achieves full opening or closing, providing rapid start-up and shutdown with low operating torque, suitable for scenarios requiring quick media cutoff. Optimized flow channel design ensures smooth internal flow, reducing fluid resistance and eddies, and lowering energy consumption.
Convenient Installation and Maintenance:
Flange connections support horizontal or vertical installation without media flow direction restrictions, adapting to different pipeline layouts.
Replaceable seals support over 50,000 pressurized opening and closing cycles with zero leakage, reducing maintenance costs.
The telescopic structure allows the valve body to shorten quickly, providing operating space for disassembling internal components (such as the butterfly plate and valve seat), reducing pipeline disassembly.
Application Scenarios
Municipal Water Supply and Drainage: Used in urban water supply pipelines and sewage treatment plant inlet and outlet pipelines to control water flow and pressure, and regulate pipeline operation. The telescopic function adapts to pipeline expansion and contraction due to temperature changes, reducing pipeline stress and preventing rupture.
Chemical and Metallurgical Industries: Used in chemical reaction equipment and pipelines to control the flow rate and proportion of chemical materials, ensuring smooth chemical reactions. Corrosion-resistant materials (such as stainless steel and fluoropolymer-lined materials) can withstand corrosive media such as acids and alkalis, preventing media leakage and pipeline blockage.
Power Industry: Used in boilers and steam pipelines to control and regulate steam flow and pressure, ensuring safe boiler operation and efficient steam utilization. The expansion function absorbs thermal expansion of steam pipelines due to temperature changes, preventing pipeline rupture.
Marine Engineering: Bidirectional sealing flange expansion butterfly valves are suitable for bidirectional flow media scenarios such as seawater desalination and reverse osmosis systems, achieving zero-leakage sealing.
Selection Points
Nominal Diameter (DN) and Pressure Rating (PN): Select DN according to pipeline size to ensure flow matching; PN must be higher than the system's maximum working pressure to consider water hammer effects. Common DN range: DN50~DN3000; Common PN range: PN0.6~PN16.
Temperature and Media Adaptability:
Temperature Range: Soft seal applicable temperature ≤120℃, hard seal applicable temperature up to 450℃.
Media Characteristics: Acidic/alkaline media require stainless steel or special coatings; food-grade media must comply with FDA standards (e.g., rubber sealing materials).
Material Selection:
Valve Body Material: Cast iron (low-pressure water systems), carbon steel (high temperature), stainless steel (corrosive environments), plastic (chemicals).
Sealing Material: Rubber (EPDM, NBR) is suitable for water or oil, with a temperature resistance ≤120℃; PTFE is corrosion-resistant and high-temperature (≤200℃), but has poor elasticity; metal seals are suitable for high-temperature and high-pressure applications (e.g., power plant flue gas, up to 600℃).
Operating Methods:
Manual: Handle or gearbox (gear reduction is required for large diameters).
Electric/Pneumatic: Remote control or automation systems (requires an actuator).
Hydraulic: High-torque applications (e.g., large-scale hydraulic projects).
Telescopic Flange Butterfly Valve in stock
