Flange Telescopic Butterfly Valve | DN32-3200 Expansion Joint Factory

A Flange Telescopic Butterfly Valve is an integrated 2-in-1 valve combining a flanged butterfly valve with a telescopic expansion joint (pipe compensator) in one body - a circular butterfly disc rotates 90° to open/close or regulate flow (butterfly valve function), while an integral telescopic (sliding) joint allows the valve's overall length to adjust axially to compensate for pipeline thermal expansion/contraction, absorb installation errors/deviations, and reduce pipeline stress - eliminating the need for a separate expansion joint + butterfly valve (saves space, cost, and leak points), with flanged ends (ANSI/DIN/BS/JIS/GB), soft seal (rubber/EPDM/NBR) or hard seal (metal), bidirectional sealing, DN32-DN3200 (super large bore to 3.2m), PN6-PN25, ≤120°C (high-temp customizable), cast iron/WCB/stainless body, stainless disc (nylon/PTFE coating optional), manual/electric/pneumatic, telescopic range customizable, for municipal water supply/drainage/heating/sewage, petrochemical, power (thermal/nuclear cooling), environmental, food/pharma/textile/paper/mining/new energy - a reliable, space-saving, cost-effective 2-in-1 flanged telescopic butterfly valve for large-bore pipeline thermal compensation + flow control. The core highlights are: (a) 2-in-1 integration (butterfly valve + telescopic expansion joint): (i) butterfly valve function - circular disc 90° rotation = on-off/flow regulation; (ii) telescopic expansion joint function - sliding spool/telescopic section allows axial length adjustment (typically ±25mm to ±100mm, customizable) = compensates pipeline thermal expansion/contraction, absorbs installation error, reduces pipe stress; (iii) replaces two components (separate butterfly valve + separate expansion joint) → saves space (one body vs two), saves cost (one valve vs two), reduces leak points (one set of flanges vs two), simplifies installation; (b) Telescopic joint principle: (i) sliding sleeve - one end of valve body has a spigot that slides into a socket on the other end (or a movable flange); (ii) seal - O-ring/gasket at sliding interface prevents leak while allowing movement; (iii) adjustable length - before/during installation, slide to match pipe spacing (compensates fabrication error, foundation settlement); (iv) thermal compensation - after installation, pipeline expands/contracts with temperature → telescopic joint moves → absorbs movement (no stress on valve/flanges); (v) telescopic range - typically ±25/50/75/100mm (customizable per DN/project); (c) Flange connection: (i) double flanges (both ends integral) - bolted to pipeline; (ii) one flange may be movable/telescopic (slides on body) to adjust length; (iii) standards: ANSI, DIN, BS, JIS, GB (global); (iv) rigid, suitable for large DN; (d) Soft or hard seal: (i) soft seal - rubber (EPDM/NBR/Viton), PTFE - zero leakage, ≤120°C (standard), water/gas/oil; (ii) hard seal - metal (stainless/Stellite) - high temp/abrasive, Class IV; (iii) seat adjustable/replaceable - can adjust compression, replace without scrapping valve; (iv) bidirectional sealing - seals from either flow direction; (e) Super large bore DN32-3200: (i) 3200mm (126" / 3.2m) = very large (one of largest butterfly valves); (ii) for large water mains, sewage, cooling water, gas mains; (iii) large DN = telescopic joint critical (pipes expand/contract more, installation errors larger); (iv) truss disc for DN >1000 (lightweight, high strength); (f) Compact + energy-saving: (i) short body (butterfly + telescopic still compact vs gate+expansion); (ii) light (less material); (iii) fully open - only disc thickness in flow → low pressure loss (K~0.2-0.5) → energy-saving (less pump power); (g) 90° quarter-turn: fast open/close, low torque (PTFE/nylon coated disc reduces friction), labor-saving; (h) Materials: body cast iron (GG25/GGG40), carbon steel WCB, stainless steel (CF8/CF8M); disc stainless steel (can be nylon sprayed or PTFE coated for corrosion/wear); seal rubber/PTFE/metal; (i) Multiple drives: manual (handwheel/lever, standard), electric (remote/DCS), pneumatic (fast/hazardous) - for large DN, worm gear/electric recommended; (j) Wide temp/pressure: ≤120°C standard (high-temp customizable with metal seal/special), PN6-PN25; (k) Standards/test: 100% pressure test (shell 1.5×PN, seat 1.1×PN), 10 inspection procedures, CE PED (Pressure Equipment Directive) certified; (l) Applications: municipal (water supply/drainage/heating/sewage), petrochemical (crude oil/gas/chemical), power (thermal circulating water, nuclear cooling), environmental (sewage/waste gas/aeration), food/pharma/textile/paper/mining/new energy (hydrogen storage/transport, PV); (m) Long life: 10+ years under normal use; (n) Customization: telescopic range, material, seal, drive, flange, high-temp. This is the reliable 2-in-1 flanged telescopic butterfly valve solution for large-bore pipeline thermal compensation + flow control.

The 2-in-1 butterfly valve + telescopic expansion joint integration, flanged connection, super large bore to DN3200, soft/hard seal options, adjustable/replaceable seat, compact energy-saving design, and customizable telescopic range make this valve a specialized large-bore pipeline compensation + isolation valve - distinct from standard butterfly valves and separate expansion joints - designed for large-bore water/gas/oil pipelines where thermal expansion/contraction, installation errors, and pipeline stress must be managed while providing on-off/flow control in one compact unit. Compared to other butterfly valves: (a) vs Electric Flange Butterfly Valve (first product): that one is general industrial electric + flanged + soft/hard seal + large-bore DN50-2000 (no telescopic function); this one is butterfly + telescopic expansion joint 2-in-1 + DN32-3200 + thermal compensation - 2-in-1 compensation vs general electric; (b) vs Fire Signal Butterfly Valve (second): that one is fire-protection signal + soft seal + DN50-400 + fire water; this one is telescopic + large-bore + general media - completely different; (c) vs Extended Flange Hard Seal Butterfly Valve (third): that one is triple-offset metal hard seal + extended flange (expansion joint function) + high temp 650°C + large-bore; this one is concentric soft/hard seal + integral telescopic sliding joint + ≤120°C + DN32-3200 - both have expansion/compensation but different: (i) Extended Flange Hard Seal = triple-offset metal hard seal (high temp, zero friction, abrasive) + extended flange (flange spacing adjustable, acts as expansion joint) - for high-temp/abrasive harsh; (ii) This Flange Telescopic = concentric soft/hard seal + integral telescopic sliding joint (independent sliding spool compensator) - for general water/gas/oil ≤120°C, large-bore, installation error/thermal compensation - different structure, different temp, different application; (d) vs Stainless Steel Handled Clamp-on (fourth): that one is all-stainless + lever handle + wafer + sanitary + small/medium; this one is cast iron/WCB/stainless + flanged + telescopic + large-bore - large-bore telescopic vs sanitary stainless wafer; (e) vs Worm Gear Flange (fifth): that one is worm gear self-locking + flanged + DN50-2200 + general industrial (no telescopic); this one is telescopic 2-in-1 + DN32-3200 + thermal compensation - 2-in-1 compensation vs worm-gear general; (f) vs Stainless Steel PTFE Wafer (sixth): that one is all-stainless + PTFE chemical + wafer + DN40-350 + chemical; this one is cast iron/WCB + telescopic + flanged + DN32-3200 + general water/gas - large-bore telescopic vs chemical PTFE wafer; (g) vs separate butterfly valve + separate expansion joint: (i) separate = two components, more space, more cost, more flanges/leak points, more installation; (ii) this 2-in-1 = one body, less space, less cost, fewer leak points, easier install - 2-in-1 advantage. Telescopic expansion joint principle detailed: (a) what is expansion joint: a device that allows pipeline axial movement (expansion/contraction) to absorb thermal stress, installation error, vibration; (b) types: (i) bellows expansion joint (metal bellows, flexible); (ii) sliding/telescopic expansion joint (spigot-and-socket sliding, with seal - this valve uses this); (iii) fabric expansion joint (rubber/fabric); (c) this valve's telescopic joint = sliding (telescopic) type: (i) one body section has a spigot (male) that slides into a socket (female) on the other section; (ii) O-ring/gasket seal at sliding interface (prevents leak while allowing axial movement); (iii) movable flange on telescopic end (can slide to adjust length, then bolt to pipe); (iv) limit bolts (optional) - prevent over-extension; (d) functions: (i) thermal expansion/contraction - pipe expands when hot (e.g., heating pipe from ambient to 120°C = expansion ~1mm per meter per 100°C; 100m pipe = 100mm expansion!) → telescopic joint absorbs; (ii) installation error - pipe fabrication/foundation error (±10-50mm) → telescopic joint adjusts to fit; (iii) foundation settlement - building/pipe support settles → telescopic joint absorbs; (iv) vibration reduction - sliding joint dampens some vibration; (e) telescopic range: (i) typically ±25mm, ±50mm, ±75mm, ±100mm (per DN/project); (ii) customizable - specify required compensation; (iii) larger DN = larger range (more expansion); (f) seal at sliding joint: (i) O-ring (NBR/EPDM) or packing; (ii) must seal under pressure while allowing movement; (iii) replaceable; (g) limitations: (i) axial only (not lateral/angulation - use bellows for that); (ii) pressure limited (≤PN25 typically); (iii) requires maintenance (sliding seal can wear). Why telescopic + butterfly in one: (a) large-bore water/heating pipes need BOTH isolation (butterfly valve) AND thermal compensation (expansion joint); (b) installing separately = valve + expansion joint + extra flanges + space; (c) 2-in-1 = one component, one set of flanges, less space, less cost, fewer leak points; (d) common in municipal water/heating (large pipes, thermal expansion significant). Large-bore (DN32-3200) consideration: (a) DN3200 = 3.2m diameter - very large (human can walk through); (b) for large water mains (city water supply, cooling water intake), sewage mains, gas mains, district heating mains; (c) large DN = (i) high flow, (ii) significant thermal expansion (long pipe runs), (iii) installation errors more likely, (iv) telescopic joint critical; (d) truss disc for DN >1000 (lightweight framework, high strength, reduces weight/inertia); (e) drive: large DN = worm gear/electric (lever impossible); (f) installation: crane/hoist required, pipe support, large flanges; (g) face-to-face per standard + telescopic range. Soft vs hard seal: (a) soft seal (rubber/EPDM/NBR/Viton/PTFE): zero leakage, ≤120°C (standard), water/gas/oil, low torque; (b) hard seal (metal/stainless/Stellite): high temp (>120°C, customizable), abrasive, Class IV leakage, higher torque; (c) seat adjustable/replaceable - can adjust compression (for wear), replace (no valve scrap); (d) bidirectional - seals both directions. Disc coating: (a) nylon sprayed - corrosion/wear resistant, low friction, for water/sewage; (b) PTFE coated - chemical corrosion, low friction; (c) bare stainless - general, food/pharma; (d) coating extends disc life. Testing: (1) body hydrostatic 1.5×PN - zero external leak (including telescopic sliding seal); (2) seat leak 1.1×PN - Class VI (soft) / Class IV (hard); (3) telescopic joint test - extend/retract to full range, verify seal (no leak at sliding joint under pressure), verify smooth movement; (4) operation (90°, torque); (5) flange dimension; (6) telescopic range (verify ±Xmm); (7) NDT for large DN; (8) CE PED (Pressure Equipment Directive) - for EU market. Maintenance: (1) periodic exercise (prevent seizure); (2) inspect leaks (flange, body, stem, telescopic sliding seal); (3) telescopic seal - if leak, replace O-ring/gasket; (4) seat - adjust/replace; (5) lubricate sliding joint (if accessible); (6) check limit bolts; (7) large DN - inspect disc (truss welds). Important: (a) telescopic joint = axial only - not for lateral/angulation (use bellows expansion joint); (b) pressure ≤PN25 (sliding seal limitation); (c) temp ≤120°C standard (higher with metal seal/special - customizable); (d) large DN - support pipe, use crane; (e) telescopic range - specify required compensation at order; (f) on-off primary (regulation optional); (g) bidirectional; (h) warranty: 18 months. The valve is manufactured under strict quality control with 100% body hydrostatic (including telescopic seal), 100% seat leak, 100% telescopic joint movement/seal test, 10 inspection procedures, CE PED certified. With an 18-month warranty and OEM/ODM customization (telescopic range, material, size, seal, drive, flange, high-temp, disc coating), this valve is a reliable 2-in-1 flanged telescopic butterfly valve for large-bore pipeline thermal compensation + flow control.

1.2-in-1 Butterfly Valve + Telescopic Expansion Joint 

Integrates butterfly valve (on-off/flow control via 90° rotating disc) and telescopic expansion joint (axial length adjustment) in one flanged body - replaces separate butterfly valve + separate expansion joint. Saves space, cost, and leak points (one set of flanges vs two). Telescopic sliding joint compensates pipeline thermal expansion/contraction, absorbs installation errors/foundation settlement, reduces pipeline stress - prevents flange leakage/damage from temperature differences and installation deviation. Telescopic range customizable (±25/50/75/100mm).

2.Super Large Bore + Flange Connection

DN32–DN3200 (1¼"–126", up to 3.2m - one of the largest butterfly valves) for large water/gas/oil mains, sewage, cooling water. Double-flange connection (ANSI, DIN, BS, JIS, GB) - rigid, suitable for large diameter, easy install/remove. One flange movable/telescopic for length adjustment. Truss disc optional for DN >1000 (lightweight, high strength). Critical for large-bore pipelines where thermal expansion and installation errors are significant.

3.Reliable Sealing + Soft/Hard Options

Soft seal (rubber/EPDM/NBR/Viton/PTFE) for zero leakage, ≤120°C, water/gas/oil; or hard seal (metal/stainless/Stellite) for high-temp/abrasive (customizable >120°C). Seat adjustable (compression can be adjusted for wear) and replaceable (no need to scrap entire valve). Bidirectional sealing - seals from either flow direction. Nylon or PTFE coated disc option enhances corrosion/wear resistance and reduces friction/torque.

4.Compact + Energy-Saving + Easy Operation

Compact structure, small volume, light weight, low material consumption, small installation size. When fully open, only disc thickness obstructs flow → low pressure loss (K~0.2-0.5), good flow state, obvious energy-saving effect (less pump power). 90° quarter-turn reciprocating rotation - quick open/close, small driving torque, labor-saving. Manual (handwheel/lever) standard; electric/pneumatic optional for automation/large DN.

5.Durable Materials + Long Service Life

Valve body: cast iron (GG25/GGG40), carbon steel (WCB), or stainless steel (CF8/CF8M) - corrosion/wear resistant. Butterfly disc: stainless steel, optional nylon-sprayed or PTFE-coated for enhanced corrosion/wear/low-friction. Stem: stainless steel (anti-blowout). All materials verified. Service life 10+ years under normal use. O-ring/gasket at telescopic sliding joint replaceable.

6.Wide Application + Standards + Warranty

PN6–PN25 (Class 125/150), ≤120°C (high-temp customizable). Media: water, gas, oil, chemicals, sewage, steam (high-temp version). For municipal water supply/drainage/heating/sewage, petrochemical (crude oil/gas/chemical), power (thermal circulating water/nuclear cooling), environmental (sewage/waste gas/aeration), food/pharma/textile/paper/mining/new energy (hydrogen/PV). 100% pressure tested, 10 inspection procedures, CE PED certified. 18-month warranty, OEM/ODM customization (telescopic range/material/size/seal/drive/flange/high-temp/disc coating).

A Flange Telescopic Butterfly Valve operates on the principle of a quarter-turn rotating circular disc (butterfly valve function) combined with an integral telescopic (sliding) expansion joint (axial length compensation) in a flanged body - turning the operator rotates the disc 90°; when the disc is parallel to flow (0°), the valve is fully open (low resistance); when rotated 90° to perpendicular, the disc compresses the seat to form a tight seal (on-off/flow control); simultaneously, the telescopic sliding joint (spigot-and-socket with O-ring seal) allows the valve's overall length to adjust axially to absorb pipeline thermal expansion/contraction, installation errors, and foundation settlement - with DN32-3200, PN6-25, soft/hard seal, cast iron/WCB/stainless body, flanged ends, manual/electric/pneumatic - a 2-in-1 flanged telescopic butterfly valve for large-bore pipeline thermal compensation + flow control. The valve consists of a flanged body (cast iron/WCB/stainless, with one fixed flange + one movable/telescopic flange), a telescopic sliding section (spigot-and-socket with O-ring/gasket seal, allows axial movement), a circular disc (stainless, nylon/PTFE coated optional, on stem), a stem (stainless, anti-blowout), a seat (soft rubber/PTFE or hard metal, adjustable/replaceable), packing (graphite/PTFE), an operator (manual handwheel/lever, electric, pneumatic), flange gaskets, and limit bolts (optional, prevent over-extension). Butterfly valve on-off principle: (1) fully open (0°): disc parallel to flow - medium flows through annular space; low resistance (K~0.2-0.5); (2) fully closed (90°): disc perpendicular - disc edge compresses seat → seal; (3) intermediate: disc at angle → throttles flow; (4) 90° rotation = fast on-off; (5) bidirectional (seat symmetric). Telescopic expansion joint principle - core: (a) what it is: a sliding (telescopic) spigot-and-socket joint integrated into the valve body - one section has a spigot (male, reduced diameter) that slides into a socket (female, larger diameter) on the other section; (b) seal: an O-ring (NBR/EPDM) or packing/gasket at the sliding interface - seals under pressure while allowing axial movement; (c) movable flange: the telescopic end has a flange that can slide along the body spigot - adjust length, then bolt to pipe; (d) movement: (i) extension - spigot slides out of socket → valve longer; (ii) retraction - spigot slides into socket → valve shorter; (e) range: typically ±25/50/75/100mm (customizable) - total travel = 2× range; (f) limit bolts (optional): bolts through lugs limit max extension (prevent spigot from pulling out of socket); (g) functions: (i) thermal expansion/contraction compensation - pipe expands when heated (e.g., steel pipe expands ~11.7μm/m/°C; 100m heating pipe from 20°C to 120°C = 100m × 100°C × 11.7e-6 = 117mm expansion!) → telescopic joint absorbs this axial movement → no stress on valve/flanges/pipe; (ii) installation error correction - pipe fabrication/foundation/erection errors (±10-50mm common) → telescopic joint adjusts to fit (no need to cut/weld pipe); (iii) foundation settlement - building/support settles over time → telescopic joint absorbs; (iv) vibration damping - sliding joint dampens some pipeline vibration (reduces transmission); (h) limitations: (i) axial only (compensates axial movement, NOT lateral or angular - use bellows expansion joint for multi-plane); (ii) pressure limited (≤PN25 typically - sliding seal can leak at higher pressure); (iii) maintenance - sliding O-ring can wear (replaceable). Why 2-in-1 (butterfly + telescopic): (a) large-bore water/heating/gas pipelines need both: (i) isolation/control (butterfly valve) - for maintenance, flow control; (ii) thermal compensation (expansion joint) - pipe expands/contracts; (b) separate components = butterfly valve + expansion joint + 4 flanges (2 per component) + more space + more cost + more leak points + more installation labor; (c) 2-in-1 integrated = one body + 2 flanges + less space + less cost + fewer leak points + easier install; (d) common in municipal/heating (large pipes, thermal expansion significant). Flange connection principle: (a) double flanges - both ends have integral flanges (one fixed, one movable/telescopic); (b) gasket between valve flange and pipe flange; (c) bolts tightened cross-pattern; (d) movable flange on telescopic end - slides to adjust length, then bolted; (e) standards: ANSI, DIN, BS, JIS, GB; (f) rigid, suitable for large DN, easy remove. Sealing principle: (a) soft seal (rubber/EPDM/NBR/Viton/PTFE): elastic seat conforms to disc → zero leakage (Class VI), ≤120°C; (b) hard seal (metal/stainless/Stellite): metal-to-metal, high temp/abrasive, Class IV; (c) floating/adjustable seat: seat ring can move slightly (self-align) and compression can be adjusted (for wear) - replaceable; (d) bidirectional: seals from either flow direction; (e) disc coating: nylon/PTFE reduces friction + corrosion → lower torque + longer life. Large-bore (DN32-3200) principle: (a) DN3200 = 3.2m - very large; (b) for large mains (water, sewage, gas, cooling); (c) truss disc for DN >1000: (i) lightweight framework (not solid disc) - reduces weight/inertia; (ii) high strength (truss structure); (iii) less material/cost; (d) drive: large DN = worm gear/electric (lever impossible - too much torque); (e) flow: large area = high flow capacity; (f) thermal expansion: large pipes = long runs = more expansion = telescopic joint critical. Operation principle: (a) manual: handwheel (worm gear for large DN) or lever (small DN) → stem → disc 90°; (b) electric: motor → gear → stem → disc (remote/DCS); (c) pneumatic: cylinder → rack-pinion → stem → disc (fast, ATEX); (d) telescopic adjustment: before/during installation, loosen movable flange bolts, slide to required length, tighten (or set after install for thermal compensation). Testing: (1) body hydrostatic 1.5×PN - zero external leak (including telescopic sliding seal - critical test); (2) seat leak 1.1×PN - Class VI (soft) / Class IV (hard); (3) telescopic joint test: (a) extend to max, retract to min - verify smooth movement; (b) seal test at both extremes (pressurize at full extension and full retraction - verify no leak at sliding O-ring); (c) verify telescopic range (±Xmm); (4) operation (90°, torque); (5) flange dimension; (6) NDT for large DN; (7) CE PED (Pressure Equipment Directive) - EU conformity. Maintenance: (1) periodic exercise (full open/close) - prevents disc/seat seizure; (2) inspect leaks: flange, body, stem, telescopic sliding seal (common wear point); (3) telescopic O-ring/gasket - if leak, replace (sliding seal wears over time); (4) seat - adjust compression or replace; (5) lubricate sliding joint (if accessible - silicone grease compatible with O-ring); (6) check limit bolts (ensure not loose/broken); (7) large DN - inspect truss disc (welds, corrosion); (8) bolts - re-torque. Important: (a) telescopic = axial only - not for lateral/angulation (use bellows); (b) pressure ≤PN25 (sliding seal); (c) temp ≤120°C standard (higher with metal seal/special - customizable); (d) large DN - support pipe, use crane; (e) telescopic range - specify at order (must match pipeline expected movement); (f) on-off primary (avoid continuous throttling at small opening - cavitation); (g) bidirectional; (h) winter - if water, drain/insulate (telescopic joint can freeze); (i) 18-month warranty. With proper installation (set telescopic range, support pipe, even flange torque), periodic exercise, and telescopic seal inspection/replacement, this 2-in-1 flanged telescopic butterfly valve provides long, reliable service in large-bore pipelines requiring thermal compensation + flow control.

- Municipal Water + Drainage + Heating + Sewage

Urban/municipal water supply mains, drainage/sewage pipelines, district heating/cooling networks, sewage treatment plants - large-bore DN32-3200 pipelines with significant thermal expansion (heating pipes) and installation errors. 2-in-1 butterfly + telescopic expansion joint replaces separate valve + expansion joint, saves space/cost/leak points. Soft seal (EPDM/NBR) for water/sewage, ≤120°C. Telescopic joint absorbs thermal movement and installation deviation. Reliable for municipal large-bore water/heating/sewage.

- Petrochemical + Oil + Gas Industry

Crude oil, natural gas, chemical product pipelines, refinery utility systems - on-off/isolation + thermal compensation for oil/gas/chemical pipelines. Cast iron/WCB/stainless body options per corrosion; soft seal (NBR/Viton) for oil/gas or hard seal for high-temp; flanged connection for process piping; telescopic joint compensates thermal expansion in long pipe runs. DN32-3200 covers process lines to large mains. Reliable for petrochemical/oil/gas pipeline isolation + compensation.

- Power Generation (Thermal + Nuclear)

Thermal power plants (circulating cooling water, boiler auxiliary, water treatment) and nuclear power (cooling water systems, service water) - large-bore cooling water mains with thermal cycling and strict safety/reliability requirements. Telescopic joint absorbs thermal expansion/contraction from temperature cycling; soft seal for cooling water; large DN for high-flow cooling mains; bidirectional sealing; 100% tested. Reliable for power plant large-bore water systems.

- Environmental Protection + Wastewater + Waste Gas

Sewage/wastewater treatment plants, waste gas treatment systems, aeration systems (air flow control in sewage aeration), flue gas desulfurization (FGD) - corrosive sewage/gas, large-bore mains. Stainless body option for corrosion; PTFE/nylon coated disc for wear/corrosion; telescopic joint compensates installation/thermal movement; soft/hard seal per media. Helps achieve energy-saving/emission-reduction goals. Reliable for environmental large-bore corrosive systems.

- Food + Pharma + Textile + Paper + Mining + New Energy

Food & beverage (process water, CIP), pharmaceutical (WFI, process water), textile/paper (water, pulp, steam with high-temp version), mining (water, slurry with hard seal), new energy (hydrogen storage/transport, photovoltaic cooling water) - diverse media/temp, DN32-3200 range. Material/seal customizable per media; manual/electric/pneumatic drive options; telescopic joint for installation flexibility. 18-month warranty, OEM/ODM customization (telescopic range/material/seal/drive/high-temp). Reliable multi-industry large-bore telescopic butterfly valve.

Our Flange Telescopic Butterfly Valves are manufactured under an ISO 9001:2015 certified quality management system, with every valve undergoing rigorous inspection and testing at each production stage - because these 2-in-1 telescopic butterfly valves are used for large-bore municipal water/heating/sewage, petrochemical, power cooling, environmental pipelines where telescopic sliding seal failure, seat leakage, body defect, flange leakage, disc failure, or inadequate telescopic range can cause water/gas/oil loss, environmental contamination, pipeline damage from thermal stress, process disruption, and costly downtime (the integrated telescopic sliding joint is a critical additional seal point that requires strict movement and pressure testing beyond standard butterfly valves).

Raw material control: every body/disc/stem material batch comes with material certificate (chemical + mechanical per heat); cast iron (GG25/GGG40) verified (tensile, hardness); WCB carbon steel verified; stainless CF8/CF8M verified by PMI; rubber/EPDM/NBR/Viton/PTFE seals verified (hardness, tensile, temp rating, aging); telescopic O-ring verified (material, dimension, compression set); fasteners verified.

Body manufacturing: (a) casting (cast iron/WCB/stainless) - sand casting; (b) heat treatment (cast iron annealing, WCB normalizing/tempering, stainless solution annealing); (c) 100% visual; (d) NDT - radiographic/ultrasonic of critical sections (body, telescopic spigot/socket, for large DN); (e) wall thickness (per standard); (f) flange machining (both ends - fixed flange + movable telescopic flange, ANSI/DIN/BS/JIS/GB, bolt hole position/flatness); (g) telescopic spigot/socket machining (precision - must slide smoothly with O-ring seal, clearances controlled); (h) seat recess machining; (i) stem bore/bearing/yoke; (j) chemical/mechanical/hardness per heat; (k) surface preparation (blast clean) + epoxy/polyester coating (blue or custom, 60-100μm, weatherproof); (l) nameplate (stainless, engraved - DN, PN, material, telescopic range).

Disc manufacturing: (a) cast/forged stainless disc (solid for <DN1000, truss for ≥DN1000); (b) machining (sealing edge, stem hole); (c) truss fabrication (weld, NDT, stress relief) if large; (d) coating - nylon spray or PTFE (if specified), or bare/polished stainless; (e) dynamic balance.

Seat manufacturing: (a) rubber/EPDM/NBR/Viton molded (hardness, tensile, aging, compression set); (b) PTFE molded/machined; (c) metal seat (stainless/Stellite); (d) dimensional check, replaceable design.

Telescopic joint components: (a) spigot (precision machined, surface finish for O-ring sealing); (b) socket (precision machined, O-ring groove); (c) O-ring (NBR/EPDM, material cert, dimensional); (d) movable flange (slides on spigot, bolt holes); (e) limit bolts (if specified); (f) sliding fit - clearance controlled (smooth movement + seal).

Stem: (a) stainless machined; (b) anti-blowout collar; (c) surface treatment.

Assembly: (1) install telescopic O-ring in socket groove; (2) assemble spigot into socket (verify smooth slide, no binding); (3) install movable flange; (4) install seat (verify adjustability); (5) install stem + anti-blowout + packing; (6) install disc (align with stem); (7) mount operator (manual/electric/pneumatic); (8) full stroke test (0-90°, smooth); (9) telescopic movement test (full extension → full retraction, smooth, no binding); (10) seat contact (uniform); (11) set limit bolts (if specified).

Pressure testing: (1) 100% body hydrostatic shell 1.5×PN - zero external leak (including telescopic sliding seal - critical); (2) 100% seat leak 1.1×PN - Class VI (soft) / Class IV (hard); (3) 100% telescopic joint seal test - pressurize at full extension AND full retraction (verify O-ring seals at both extremes, no leak); (4) 100% air tightness (low-pressure); (5) strength + seal per standard. Function testing: open/close 90° travel, operation torque, telescopic range verification (±Xmm, measure), telescopic movement (smooth at full range), seat sealing, flange dimensions, face-to-face (extended/retracted), movable flange (slides freely), limit bolts (if specified), coating thickness/adhesion, nameplate marking.

Large DN testing (DN >1000): (a) NDT body/disc (truss welds); (b) dimensional (flange, telescopic); (c) operation (with specified drive); (d) may require hydrotest at site (if too large for factory test rig - witness test). 10 inspection procedures (as stated): typically (1) raw material, (2) casting, (3) heat treatment, (4) machining (flange/telescopic), (5) seat/O-ring, (6) assembly, (7) body hydrostatic, (8) seat leak, (9) telescopic joint test, (10) final inspection/coating/packing.

CE PED certification: (a) PED (Pressure Equipment Directive 2014/68/EU) - EU conformity for pressure equipment; (b) module assessment (per category - typically Category II/III for valves); (c) CE marking on nameplate; (d) technical file + EU declaration of conformity; (e) for EU market export. Coating & marking: exterior - epoxy/polyester coating (blue RAL 5010/5015 standard, or customer color), 60-100μm, weatherproof; interior - bare or coating per media; valve permanently marked with DN, PN, material, seal, standard, telescopic range, flow direction, manufacturer, year, CE mark; nameplate (stainless, engraved).

Documentation: shipped with hydrostatic test report (including telescopic seal), material certificate, seat leak report, telescopic joint test report (range + seal at extremes), CE PED certificate/declaration, and installation/operation/maintenance manual (including telescopic range setting, sliding seal maintenance, large-bore installation).

Warranty: 18 months from shipment or 12 months from installation (valve body, including telescopic joint); electric/pneumatic actuator 12 months; extended warranty and third-party inspection (BV, SGS, TUV), special certifications available.

Q: How does the telescopic expansion joint work, and why combine it with a butterfly valve?

A: The telescopic expansion joint (also called sliding expansion joint, telescopic compensator, or spigot-and-socket expansion joint) is the core unique feature of this valve - it allows the valve's overall length to change axially to absorb pipeline movement, while the butterfly valve provides on-off/flow control - combining both in one body saves space, cost, and leak points. How the telescopic joint works (mechanical): (a) Structure: the valve body is split into two sections - one section has a spigot (a male, reduced-diameter extension), the other has a socket (a female, larger-diameter bore); the spigot slides inside the socket like a telescope (hence "telescopic"); (b) Seal: an O-ring (NBR/EPDM) or packing/gasket sits in a groove at the spigot/socket interface - this O-ring seals against the sliding surface, preventing medium leakage while still allowing the spigot to slide axially; (c) Movable flange: the telescopic end has a flange that can slide freely along the spigot - during installation, you slide this flange to match the pipe spacing, then bolt it to the pipeline flange; (d) Movement: (i) extension - spigot slides OUT of socket → valve gets longer (compensates pipe contraction / cold pipe); (ii) retraction - spigot slides INTO socket → valve gets shorter (compensates pipe expansion / hot pipe); (e) Range: typically ±25mm, ±50mm, ±75mm, ±100mm (meaning total travel = 50/100/150/200mm) - customizable per project; (f) Limit bolts (optional): bolts through lugs on both sections limit maximum extension (prevent spigot from pulling out of socket under pressure/vacuum). What the telescopic joint compensates: (a) Thermal expansion/contraction - this is the #1 purpose: (i) steel pipe expands when heated: coefficient of thermal expansion for steel ≈ 11.7 × 10⁻⁶ m/m/°C (or 0.0117 mm/m/°C); (ii) example: a 100-meter district heating pipe heated from 20°C (ambient) to 120°C (hot water) = 100m × 100°C × 0.0117mm/m/°C = 117mm expansion; (iii) without compensation, this 117mm expansion would create huge stress on pipes, flanges, valves (could bend pipe, break flanges, leak); (iv) telescopic joint absorbs this 117mm (specify ±75mm or ±100mm range); (b) Installation error/fabrication deviation - pipes are never perfectly fabricated/erected: (i) pipe length errors (±5-20mm); (ii) flange misalignment; (iii) foundation/anchor bolt position errors; (iv) telescopic joint adjusts to fit (no need to cut/weld/reweld pipe - saves installation time); (c) Foundation settlement - buildings/pipe supports settle over time (mm to cm) → telescopic joint absorbs axial component; (d) Vibration reduction - sliding joint with O-ring dampens some pipeline vibration (pump vibration, water hammer) - reduces transmission to equipment. Why combine with butterfly valve (2-in-1): (a) Large-bore pipelines need BOTH: (i) isolation/control (butterfly valve) - for maintenance shutdown, flow control; (ii) thermal compensation (expansion joint) - pipe expands/contracts; (b) Traditional (separate): install a butterfly valve AND a separate expansion joint = (i) 2 components; (ii) 4 flanges (2 per component) + gaskets + bolts; (iii) more space (2 bodies); (iv) more cost (2 products); (v) more leak points (4 flange joints); (vi) more installation labor; (c) 2-in-1 (this valve): butterfly + telescopic in ONE body = (i) 1 component; (ii) 2 flanges; (iii) less space; (iv) less cost; (v) fewer leak points (2 flange joints); (vi) easier/faster installation; (d) 2-in-1 advantage = especially valuable for large-bore (DN >500) where separate components are heavy/expensive/space-consuming. Telescopic joint vs bellows expansion joint: (a) Telescopic (sliding) - this valve: (i) spigot-and-socket sliding + O-ring; (ii) axial only movement; (iii) pressure ≤PN25; (iv) simple, robust, low cost; (v) requires O-ring maintenance; (b) Bellows (metal bellows): (i) flexible metal bellows (convoluted); (ii) axial + lateral + angular movement (multi-plane); (iii) higher pressure; (iv) more expensive, bellows can fatigue/crack; (v) no sliding seal (bellows itself is the seal); (c) this valve uses telescopic - for axial-only compensation, cost-effective, large-bore water/gas. Limitations of telescopic joint: (a) axial ONLY - cannot compensate lateral (sideways) or angular (bending) movement (if pipeline has lateral/angulation, use bellows expansion joint or install with guides); (b) pressure limited - typically ≤PN25 (sliding O-ring can leak at higher pressure; for >PN25, use bellows or high-pressure telescopic with multiple seals); (c) maintenance - O-ring at sliding joint can wear over time (replaceable - inspect periodically); (d) not for vacuum (may pull spigot out - use limit bolts); (e) temperature - O-ring temp limit (≤120°C standard; higher with special O-ring/metal seal). How to set telescopic range at installation: (a) determine pipeline expected movement (thermal expansion calculation: ΔL = L × α × ΔT); (b) select valve telescopic range ≥ expected movement (with safety margin 1.5×); (c) at installation, set valve to mid-position (half-extended) so it can move both directions (expand + contract); (d) tighten movable flange bolts to pipe; (e) do NOT set at full extension or full retraction (no room for movement in one direction); (f) install pipe guides/supports on both sides (telescopic joint should not support pipe weight - it only compensates axial movement). Common mistakes: (a) not calculating thermal expansion - undersized telescopic range (pipe stress, leaks); (b) setting at full extension/retraction - no movement room; (c) using for lateral/angulation - damages O-ring/spigot; (d) no pipe guides - pipe weight on telescopic joint (wears/binds); (e) ignoring O-ring maintenance - sliding seal leaks over time. This valve's telescopic joint = sliding spigot-and-socket with O-ring, customizable range, axial compensation, 2-in-1 with butterfly - ideal for large-bore water/heating/gas pipelines needing isolation + thermal compensation.

Q: What size/pressure/temperature can this valve handle, and what does DN3200 mean?

A: Size (DN): DN32–DN3200 (1¼"–126") - an extremely wide range, from small process lines to very large mains. (a) DN32-100: small lines, branches, HVAC; (b) DN100-500: medium process/water mains; (c) DN500-1200: large water/sewage/gas mains; (d) DN1200-3200: very large - city water supply mains, cooling water intake, sewage outfalls, gas mains; (e) DN3200 = 3200mm = 3.2 meters = 126 inches ≈ 10.5 feet - a human can walk through; this is one of the largest butterfly valves manufactured; (f) custom sizes available. What DN3200 means in practice: (a) flow capacity: at 2m/s water velocity, DN3200 carries ~57,000 m³/h (57 million liters/hour) - enough for a city of ~1-2 million people; (b) weight: a DN3200 valve can weigh 5-20+ tons (depending on material/pressure) - requires heavy crane for installation; (c) flange: 3.2m diameter flange with ~40-60 large bolts (M36-M48); (d) disc: must be truss-type (lightweight framework) - solid disc would be too heavy/inert; (e) drive: electric or hydraulic (manual impossible); (f) installation: special rigging, pipe support, large crane, multiple workers. Pressure (PN): PN6, PN10, PN16, PN25 (0.6/1.0/1.6/2.5 MPa); also Class 125, Class 150 (ANSI). (a) PN6: very large water mains, low pressure; (b) PN10/16: most common (water, gas, oil, heating, sewage); (c) PN25: higher pressure (process, smaller DN); (d) Class 125/150 - ANSI standard (interchangeable with PN10/20 roughly); (e) not for >PN25 - telescopic sliding seal limitation (O-ring at sliding joint can leak at higher pressure; use bellows or high-pressure design for >PN25). Temperature: ≤120°C (standard, with soft rubber/EPDM/NBR seal). (a) soft seal temp: EPDM ≤120°C, NBR ≤80°C, Viton ≤200°C, PTFE ≤200°C; (b) ≤120°C standard = covers most water/heating/oil/gas; (c) high-temperature customizable: >120°C (up to 250-450°C) with metal hard seal + special telescopic O-ring (e.g., graphite packing, high-temp elastomer) - specify at order; (d) body temp: cast iron ≤350°C, WCB ≤425°C, stainless ≤425°C (but seal/O-ring limits actual); (e) low temp: -20~-40°C (with special O-ring, e.g., low-temp NBR/EPDM). Pressure-temperature interaction: (a) higher temp = lower pressure rating (O-ring/seat softens); (b) at 120°C, PN16 may be derated (consult chart); (c) for high temp + high pressure, use metal seal + special telescopic design. Telescopic range: (a) customizable per pipeline requirement; (b) typical: ±25mm (DN<200), ±50mm (DN200-600), ±75mm (DN600-1200), ±100mm (DN>1200); (c) larger DN = larger range (more thermal expansion in long large pipes); (d) calculate required range: ΔL = L × α × ΔT (L = pipe length, α = 11.7e-6 /°C for steel, ΔT = temp change); (e) add safety factor 1.5×. Size-pressure-temp limits summary: (a) DN32-3200, PN6-25, ≤120°C = standard range; (b) beyond = custom/other valve type; (c) DN >3200 → special order (rare, may use radial gate / other); (d) PN >25 → bellows expansion joint or high-pressure valve; (e) temp >120°C → metal seal + special telescopic (customizable); (f) lateral/angulation compensation → bellows (not telescopic). Selection example: (a) district heating main, DN800, PN16, 120°C water, 200m pipe run → this valve (DN800 PN16 ≤120°C, telescopic range ±75mm - 200m × 100°C × 11.7e-6 = 234mm expansion → need ±125mm or two valves - specify); (b) city water main, DN2000, PN10, ambient, 500m → this valve (DN2000 PN10, telescopic ±100mm - ambient temp change small); (c) cooling water, DN1200, PN10, 40°C → this valve (within range); (d) steam, DN200, PN25, 250°C → NOT standard (temp >120°C - use high-temp customizable version with metal seal); (e) high-pressure oil, DN100, PN40, 80°C → NOT (PN>25 - use other valve/bellows). Important: (a) DN3200 is very large - confirm transport/installation access (road transport, crane capacity, pipe support); (b) telescopic range must be calculated - don't guess (thermal expansion depends on pipe length + temp change); (c) PN25 max (telescopic seal); (d) ≤120°C standard (specify high-temp if needed); (e) axial only compensation; (f) specify actual conditions (DN/PN/temp/media/pipe length/temp change/telescopic range) when ordering - we confirm compatibility and recommend range. This valve = DN32-3200 (super large), PN6-25, ≤120°C (high-temp customizable), telescopic range customizable - ideal for large-bore water/gas/heating/sewage pipelines needing isolation + thermal compensation.

Q: Soft seal vs hard seal - which do I need, and is the seat replaceable?

A: This valve offers two sealing configurations: soft seal (standard) and hard seal (optional, for high-temp/abrasive). The seat is adjustable and replaceable (can adjust compression for wear, or replace without scrapping the entire valve). Soft Seal (standard - rubber/EPDM/NBR/Viton/PTFE): (a) Construction: elastic rubber/PTFE seat ring; (b) Leakage: Class VI (zero visible / bubble-tight) - very tight; (c) Materials: (i) EPDM: water/steam/ozone, -40~120°C, HVAC/heating/water (most common for this valve's ≤120°C); (ii) NBR (nitrile): oil/water, -20~80°C, oil/gas; (iii) Viton (FKM): high-temp oil/chemical, -20~200°C, premium; (iv) PTFE: chemical/corrosive, -40~200°C, low friction; (d) Advantages: zero leakage, low torque, low cost, good for water/gas/oil ≤120°C; (e) Limitations: temp limited (≤120°C standard, ≤200°C Viton/PTFE), can wear in abrasive media; (f) Use: municipal water/heating/sewage, oil/gas, general (90% of applications for this valve). Hard Seal (optional - metal/stainless/Stellite): (a) Construction: metal-to-metal seat (stainless or Stellite hardfaced); (b) Leakage: Class IV (low leakage, but NOT zero - metal doesn't conform perfectly); (c) Advantages: high temp (>120°C, up to 250-450°C), abrasive media (slurry, dust), fire-safe (doesn't burn), long wear life; (d) Limitations: leaks (Class IV), higher torque, higher cost, not for zero-leak requirement; (e) Use: high-temp steam/hot oil, abrasive dust/slurry, fire-risk areas, customizable high-temp version. Seat adjustability + replaceability: (a) Adjustable: seat ring compression can be adjusted via bolts/gland - as seat wears, tighten to restore seal (extends seat life); (b) Replaceable: seat ring is bolted/pressed - can remove and replace (no need to scrap entire valve); (c) Benefit: lower total cost (replace $100 seat vs $5000 valve), less downtime; (d) telescopic O-ring also replaceable (sliding joint seal - common wear point). Selection guide: Choose soft seal if: (a) water, gas, oil, general chemical (non-abrasive); (b) zero leakage required (environmental, water loss); (c) temp ≤120°C (EPDM) or ≤200°C (Viton/PTFE); (d) non-abrasive media; (e) cost-sensitive (90% of this valve's applications - municipal water/heating/sewage, oil/gas). Choose hard seal if: (a) temp >120°C (high-temp steam/hot oil - customizable version); (b) abrasive media (slurry, dust, particles); (c) fire-risk area (metal doesn't burn); (d) can tolerate Class IV leakage. Seal material compatibility: (a) water (potable/heating/cooling): EPDM (best, ≤120°C) - this valve's standard; (b) oil/fuel/hydrocarbon: NBR or Viton (NOT EPDM - EPDM swells in oil); (c) chemical/acid/alkali/solvent: PTFE; (d) steam (≤120°C): EPDM; (e) high temp >120°C: metal seal (customizable); (f) abrasive slurry: metal seal (or knife gate). Disc coating (related to seal/wear): (a) nylon sprayed: corrosion/wear resistant, low friction, for water/sewage; (b) PTFE coated: chemical corrosion, low friction; (c) bare stainless: general, food/pharma; (d) coating reduces disc wear + friction (lower torque) + extends seat life. Common mistakes: (a) using EPDM for oil (swells/fails - use NBR/Viton); (b) using soft seal for >120°C (fails - use metal/high-temp); (c) using soft seal for abrasive slurry (wears fast - use metal/knife gate); (d) not adjusting seat as it wears (leak - adjust/replace); (e) ignoring telescopic O-ring (sliding seal - replace if leaks). This valve: standard soft seal (specify EPDM/NBR/Viton/PTFE), optional hard seal (metal/Stellite, for high-temp/abrasive), seat adjustable + replaceable, telescopic O-ring replaceable. Important: (a) seat is replaceable - order spare seat with valve; (b) adjust as wears (don't wait for heavy leak); (c) telescopic O-ring - also replaceable (inspect periodically); (d) high-temp version - specify at order (metal seal + special telescopic seal); (e) tested - 100% seat leak test (1.1×PN).

Q: How do I install a large-diameter flange telescopic butterfly valve, and how do I set the telescopic range?

A: Installation (critical for telescopic valves): (1) Verify: check DN, PN, body material, seal material, flange standard, telescopic range (±Xmm), face-to-face (min/max) - match pipeline; (2) Calculate telescopic requirement: (a) thermal expansion: ΔL = L × α × ΔT (L = pipe length between anchors, α = 11.7e-6 /°C for steel, ΔT = max temp change); (b) installation error: add ±10-30mm; (c) total required range = ΔL + installation error + safety factor (1.5×); (d) confirm valve telescopic range ≥ required; (3) Inspect: remove protectors, inspect flange faces, seat, disc, telescopic spigot/socket (no damage, O-ring intact, slides smoothly), stem, operator; (4) Set telescopic to mid-position: (a) extend/retract valve to midpoint of telescopic range (e.g., if range ±50mm, set at 0mm / center); (b) this allows movement in BOTH directions (expand + contract); (c) do NOT set at full extension or full retraction (no room); (5) Orientation: can install any orientation (horizontal/vertical/angled); recommend stem horizontal or operator accessible; for large DN, operator accessible; (6) Gaskets: place gaskets on BOTH sides (rubber/PTFE/spiral wound - match media/temp); (7) Position: lift valve (crane/hoist for DN >300 - do NOT lift by operator/telescopic section), align flanges, insert bolts; (8) Adjust telescopic length: if pipe spacing doesn't match, slide movable flange / extend-retract valve to fit (within range), then align; (9) Torque: tighten flange bolts cross-pattern (3-4 passes, final torque per spec/DN) - even clamping; (10) Install pipe guides/supports: CRITICAL - install pipe anchors + guides/supports on both sides near valve: (a) anchor at one point (fixes pipe); (b) guide/support near valve (allows axial movement, prevents lateral/vertical load on telescopic joint); (c) telescopic joint should NOT support pipe weight (it only compensates axial movement - pipe weight will bind/wear/damage sliding joint); (11) Set limit bolts (if equipped): adjust to allow full telescopic range but prevent over-extension; (12) Pre-operation: partially open valve (10-15°) before pressurizing, then pressurize slowly; (13) Test: pressurize, check external leaks (flange, body, stem, telescopic sliding seal), operate full open/close, verify telescopic movement (pipe expands/contracts - observe), check no binding. Setting telescopic range - detailed: (a) Determine pipe anchor points: identify where pipe is fixed (anchors) - telescopic joint compensates movement between anchors; (b) Calculate expansion: ΔL = L × α × ΔT; (c) Example: 100m heating pipe, 20°C→120°C = 100 × 100 × 11.7e-6 = 0.117m = 117mm; (d) Select range: need ≥117mm total → choose ±75mm (150mm total) or ±100mm (200mm total); (e) Install at mid-position: set valve at center (0mm) → can expand +75mm and contract -75mm; (f) Multiple valves: for very long pipes, install multiple telescopic valves (each handles a section); (g) Seasonal adjustment: in extreme climates, may need to readjust mid-position seasonally (summer vs winter). Large DN special considerations: (a) DN >500: use crane/hoist; (b) DN >1000: truss disc, very heavy (tons), special rigging; (c) DN >2000: may require site assembly/welding, special transport; (d) support pipe (large pipe weight); (e) flange bolts large (M30-M48), use torque wrench; (f) scaffolding/platform for operator access. Maintenance: (1) Periodic exercise: full open/close every 3-6 months (prevents seizure); (2) Inspect telescopic joint: (a) external leak at sliding seal (O-ring worn - replace); (b) movement (verify it can slide - if bound, check pipe guides/support); (c) limit bolts (secure); (3) Inspect leaks: flange, body, stem; (4) Seat: adjust/replace if leak; (5) Telescopic O-ring: replace if leak (sliding joint seal - common wear point); (6) Lubricate sliding joint (if accessible - silicone grease compatible with O-ring, do not use grease that swells O-ring); (7) Pipe guides/supports: check (ensure no pipe weight on valve); (8) Bolts: re-torque after thermal cycle; (9) Seasonal check: in extreme climates, verify mid-position (pipe may have moved). Troubleshooting: (a) Leak at telescopic sliding joint: (i) O-ring worn/cut (replace); (ii) spigot/socket scored (polish/replace); (iii) over-pressure (exceeds PN25 - use higher rating); (iv) pipe lateral load (guides failed - realign); (b) Telescopic joint bound/won't move: (i) pipe weight on joint (install guides/supports); (ii) O-ring swollen (wrong chemical - replace with compatible); (iii) spigot/socket corroded (clean/replace); (iv) limit bolts too tight (adjust); (c) Seat leakage: adjust/replace seat; (d) Flange leak: tighten/replace gasket; (e) Hard to operate: seat seized (exercise), stem/packing (lubricate), high torque (normal for large DN); (f) Valve/noisy/vibrates: cavitation (throttling at small opening - avoid), water hammer (slow open/close), pipe vibration (guides). Important: (a) always calculate telescopic range (don't guess); (b) install at mid-position (room both directions); (c) pipe guides/supports are MANDATORY (telescopic joint not load-bearing); (d) do not lift by telescopic section/operator (lift by body/flanges); (e) large DN - crane, support, torque wrench; (f) telescopic O-ring - inspect/replace periodically; (g) isolate/depressurize before maintenance; (h) 18-month warranty. With proper installation (calculate range, mid-position, pipe guides/supports, even torque), periodic exercise, and telescopic seal inspection, this flange telescopic butterfly valve provides long, reliable service in large-bore pipelines requiring thermal compensation + flow control.

Q: What standards does this valve meet, and what is CE PED certification?

A: This valve is designed and tested to several international standards, with CE PED certification for the European market. Design/manufacturing standards: (a) API 609 - "Butterfly Valves: Double Flanged, Lug, and Wafer Type" (American Petroleum Institute) - design, materials, face-to-face, pressure-temperature for industrial butterfly valves; (b) MSS SP-67 - "Butterfly Valves" (Manufacturers Standardization Society) - similar to API 609, US standard; (c) EN 558-1 - European standard for face-to-face dimensions (short pattern butterfly valves) - interchangeability; (d) GB/T 12238 - Chinese standard for butterfly valves; (e) expansion joint standards: (i) GB/T 12777 - Chinese standard for metal bellows expansion joints (reference); (ii) EJMA - Expansion Joint Manufacturers Association (US, for bellows - reference); (iii) telescopic (sliding) joints often per company spec + project spec. Flange standards: (a) ANSI B16.1 (cast iron flanges, Class 125/250); (b) ASME B16.5 (steel flanges, Class 150-2500); (c) DIN 2501 (German, PN); (d) BS 4504 (British, PN); (e) JIS 10K/16K (Japanese); (f) GB/T 9113 (Chinese); (g) EN 1092 (European). Testing standards: (a) API 598 - "Valve Inspection and Testing" (shell 1.5×PN, seat 1.1×PN); (b) GB/T 13927 - Chinese industrial valve pressure test; (c) EN 12266-1 - European industrial valve testing (Class A zero leak for soft seal); (d) ISO 5208 - international valve pressure testing. CE PED certification - what it is: (a) PED = Pressure Equipment Directive 2014/68/EU - European Union regulation for pressure equipment (valves, pipes, vessels, etc. that contain pressure); (b) purpose: ensure pressure equipment is safe (no explosion/failure) when placed on EU market; (c) categories: equipment classified by pressure × volume × fluid group (Category I, II, III, IV - higher = more dangerous = stricter); (d) valves: typically Category II or III (depending on size/pressure/fluid); (e) conformity assessment modules: (i) Module A (internal production control, Category I - self-declare); (ii) Module A2 + D1/E1 etc. (Category II/III - notified body involved); (iii) Module B+D/F/G/H (Category IV - full quality system + type examination); (f) CE marking: after conformity assessment, valve gets CE mark on nameplate + EU Declaration of Conformity; (g) without CE PED, valve cannot be legally placed on EU market (for applicable categories). What CE PED means for you: (a) if you are in EU/EEA or project requires EU compliance, CE PED is mandatory (for Category II+ valves); (b) our valves are CE PED certified (with technical file, declaration, CE mark) - can export to EU; (c) notified body (e.g., TUV, SGS, BV) involved for Category II+; (d) documentation: we provide EU Declaration of Conformity + technical file summary. Other certifications (optional): (a) ISO 9001 - quality management (we have); (b) API 6D - pipeline valves (optional, for oil/gas pipeline); (c) API 607 - fire-safe (optional, if metal seal + fire-safe design); (d) FDA - food contact (316L/EPDM/PTFE, optional); (e) WRAS/NSF 61 - drinking water (optional, for potable water); (f) third-party inspection - BV/SGS/TUV (witness test, material cert). 10 inspection procedures: (as stated on page) typically: (1) raw material inspection (cert + PMI); (2) casting inspection (visual, dimensions); (3) heat treatment (hardness, microstructure); (4) machining inspection (flange, telescopic spigot/socket, seat, tolerances); (5) seat/O-ring inspection (material, dimension); (6) assembly inspection (fit, movement); (7) body hydrostatic test (1.5×PN, including telescopic seal); (8) seat leak test (1.1×PN); (9) telescopic joint test (range + seal at extremes); (10) final inspection (coating, marking, packing, documentation). 100% pressure test: (a) every valve is pressure tested (not sampling); (b) shell test 1.5×PN (body + telescopic joint); (c) seat test 1.1×PN; (d) telescopic seal test at full extension + full retraction; (e) records kept. Why standards matter: (a) interchangeability (flange, face-to-face); (b) quality/safety (minimum requirements); (c) project specification (EPC/engineering firms specify); (d) legal/market access (CE PED for EU). Important: (a) specify project standard when ordering (e.g., "API 609, EN 558-1, CE PED Category III, ANSI B16.5"); (b) CE PED category depends on DN/PN/fluid - confirm with us; (c) face-to-face - verify (standard + telescopic range adds length); (d) flange standard must match pipeline; (e) telescopic joint - often per project spec (range, pressure, temp) - specify. This valve meets: API 609, MSS SP-67, EN 558-1 (design/face-to-face), API 598/GB 13927/EN 12266-1 (test), ANSI/DIN/BS/JIS/GB flanges, CE PED certified, 100% pressure tested, 10 inspection procedures.

Q: What is the warranty, and what does it cover (especially the telescopic joint)?

A: Warranty period: 18 months from shipment date (or 12 months from installation date, whichever comes first) for the valve body - this includes the telescopic expansion joint (body, telescopic spigot/socket, sliding seal, flanges, disc, stem, seat). Electric/pneumatic actuator: 12 months from shipment (if equipped). What is covered: (a) defects in materials (body casting defect, wrong material, stem material defect, telescopic spigot/socket machining defect); (b) defects in workmanship (poor machining, assembly error, welding defect, O-ring groove defect); (c) telescopic joint failure from manufacturing defect (e.g., spigot/socket misalignment causing binding, O-ring groove defect causing leak, defective O-ring material); (d) seat failure under normal use (within rating) - e.g., seat leaks prematurely (not from wear/abrasive); (e) seal leakage from manufacturing defect (not normal wear); (f) coating defect - premature peeling/corrosion (not from damage/abrasion). What is NOT covered: (a) normal wear and tear - seat wear, telescopic O-ring wear (O-ring is a wear item at sliding joint), packing wear, disc coating wear; (b) improper installation - wrong telescopic range, no pipe guides/supports (pipe weight on telescopic joint causing damage), over-torque, wrong gaskets, wrong orientation; (c) exceeding ratings - pressure >PN25, temperature >120°C (without high-temp version), wrong media (e.g., EPDM in oil); (d) abrasive/corrosive media beyond spec - slurry wearing soft seat, strong chemical without PTFE; (e) accident/damage - impact, fire, freezing (water freeze cracks), water hammer from improper operation; (f) unauthorized repair/modification - altering valve, using non-genuine parts; (g) lack of maintenance - no exercise, telescopic O-ring not replaced, pipe guides failed; (h) consequential damages - process downtime, product loss, labor (we cover valve repair/replacement only, unless contract specifies). Telescopic joint specific warranty notes: (a) telescopic O-ring = wear item (slides continuously as pipe expands/contracts) - normal wear NOT covered (replace periodically); (b) telescopic body/spigot/socket = covered for manufacturing defect (not for damage from pipe weight/lateral load - that's installation error); (c) if telescopic joint leaks due to O-ring wear = normal maintenance (replace O-ring - not warranty); (d) if telescopic joint leaks due to defective spigot surface (scored from factory) = warranty; (e) if telescopic joint binds due to no pipe guides = installation error (not warranty). Warranty claim process: (a) notify us within 30 days of discovering defect (email: Contact@thankfulmaterial.com, phone: +86-15094398934); (b) provide evidence: photos/videos of defect, valve nameplate (DN/PN/material/telescopic range/year), operating conditions (media/temp/pressure/pipe length), installation details (pipe guides, telescopic setting); (c) we evaluate - may request return for inspection; (d) remedy: repair (send parts, guide), replacement (new valve/part), refund; (e) timeline: 7-30 days. Consumable/wear parts (not warrantied long-term): (a) seat ring (soft/hard) - normal life 5-10 years; (b) telescopic O-ring/gasket - normal life 3-8 years (depending on movement frequency/temp/media); (c) packing - 5-10 years; (d) gaskets - replace at installation; (e) these are maintenance items. Extended warranty options: (a) 24 months - +5-10% valve price; (b) 36 months - +10-15%; (c) includes same coverage; (d) specify at order. Service/support beyond warranty: (a) spare parts supply - seat, telescopic O-ring, disc, stem, packing, gaskets, bolts, actuator for 10+ years; (b) technical support - installation (telescopic range calculation, pipe guides), maintenance, troubleshooting (free, lifetime); (c) repair service - factory repair; (d) on-site service - optional (engineer visit, for large DN/projects); (e) OEM/ODM - custom valves. Important warranty notes: (a) warranty starts at shipment (not delivery/installation); (b) 12 months from installation cap - if installed 6 months after shipment, warranty = 12 months from installation (total 18 months from shipment); (c) keep records - installation date, telescopic setting, maintenance (help with claims); (d) genuine parts - use our spare parts (non-genuine voids warranty); (e) telescopic O-ring - inspect/replace periodically (wear item, not warranty); (f) pipe guides/supports - must be installed (damage from lack of guides = not warranty); (g) actuator separate 12-month warranty. This valve = 18-month standard warranty (body + telescopic joint), 12-month actuator, extendable to 24/36 months - with reliable spare parts (especially telescopic O-ring) and lifetime technical support (including telescopic range calculation + installation guidance).

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