Specification

TIANYU Triple Offset Metal Hard-Seal Flanged Butterfly Valve: Reliable Control for Harsh Industrial Conditions

I. Product Technical Overview

The TIANYU triple offset metal hard-seal flanged butterfly valve features a triple-eccentric geometry (offsets between the stem axis, disc center, sealing surface centerline, and disc rotation axis). Equipped with a worm gear actuator, it uses ductile iron/WCB body, stainless steel disc with Stellite hard-seal coating, and stainless steel stem. Designed for high-temperature (≤425℃), high-pressure (≤6.4MPa), corrosive/abrasive media (e.g., petrochemical steam, power plant desulfurization slurry, metallurgical gas, municipal heating), it meets strict shut-off and regulation needs in industrial piping systems.

II. Core Advantages

(A) Triple-Eccentric Structure: Zero Friction & Self-Tightening Seal

Three Offsets:
1. Radial offset (stem vs. disc center).
2. Axial offset (stem vs. sealing surface centerline).
3. Angular offset (sealing surface vs. disc rotation axis).
  The disc disengages from the seat within 5° of opening (near-zero friction) and self-tightens during closing, achieving ANSI/FCI 70-2 Class VI bubble-tight leakage (metal-to-metal seal).
Extended Lifespan: Eliminates seal wear during operation, doubling service life in abrasive media (e.g., blast furnace gas) compared to double-offset valves.

(B) Metal Hard-Seal System: Harsh Condition Adaptability

Seal Technology:
The disc’s sealing surface uses Stellite 6/21 hard alloy overlay (≥2mm thickness) via plasma cladding, ensuring ≥200MPa bond strength, HRC 45-55 hardness, and resistance to 800℃ short-term heat and particle erosion (e.g., coal dust, slag).
Bidirectional Sealing:
Combines triple eccentricity with metal sealing for bidirectional zero leakage, suitable for high-temperature steam (350℃, 4.0MPa) and corrosive slurries (pH 2-12).

(C) Worm Gear Actuation: High Torque & Precision

Torque Efficiency:
Worm gearboxes (ratio 1:30–1:60) deliver ≥1000N·m torque (DN300), ideal for large diameters (≤DN1200). Manual operation requires ≤80N·m (API 609 compliant).
Mechanical Lock:
Worm gear drive provides self-locking to prevent disc movement from media backpressure, ensuring system safety (e.g., high-pressure steam lines).

(D) Material Synergy: Corrosion & Strength Balance

Component	Material	Key Properties
Body	Ductile Iron (QT450)/WCB	QT450: ≥450MPa tensile, ≥27J impact at -20℃; WCB: ≤425℃, hydrogen embrittlement resistance.
Disc	Stainless Steel (304/316L) + Stellite	Stainless steel base for corrosion resistance; hard alloy for wear/heat resistance.
Stem	2Cr13/17-4PH Stainless Steel	Nitrided surface (0.3mm depth), ≥900MPa torsional strength, blowout-proof (API 600).
Seal	Metal Hard-Seal (Optional Soft Seal)	Hard seal: ≤425℃; Soft seal (EPDM): ≤180℃, for clean media.

III. Technical Specifications

Parameter	Standard	Custom Options
Size	DN50–DN1200	Up to DN1600 (engineered evaluation).
Pressure Class	PN10–PN63 (1.0–6.4MPa)	ASME Class 150–900 (2.0–15.0MPa, WCB body).
End Connection	Flange (GB/T 9113/ANSI B16.5)	Wafer (GB/T 12238), welded.
Design Standards	GB/T 12238, API 609	CE, ATEX (explosion-proof actuation).
Testing	GB/T 13927, API 598	Fire-safe testing (API 607).
Actuation	Worm Gear (Manual)	Electric/pneumatic (4-20mA control).

Product Overview

IV. Manufacturing & Quality

(A) Precision Manufacturing

Body Casting:
- Ductile iron: Lost foam casting + annealing (ferrite ≥85%).
- WCB: Resin sand casting + normalizing/tempering (grain size ≥6).
- NDT: 100% UT (WCB) / MT (ductile iron), defects ≤JB/T 6059 Level 2.
Disc & Seal Processing:
- Stainless steel disc: 5-axis CNC machining (roundness ≤0.02mm, Ra≤0.8μm).
- Stellite overlay: Plasma cladding (≥2mm thickness, 500-hour salt spray tested).
Actuator Assembly:
- Worm gearbox: Precision hobbing (class 6 accuracy, backlash ≤0.05mm).
- Valve testing: 1.5× hydrostatic (30-minute hold), 1.1× helium leak (≤1×10⁻⁴ mbar·L/s).

(B) Quality Assurance

Traceability: Material heat numbers, CMA reports, and third-party PMI testing.
Certifications: ISO 9001, API 609, ATEX II 2G Ex db IIC T4 (explosion-proof).
Warranty: 24-month coverage for manufacturing defects (seal failure, structural deformation).

Valve Details

VI. TIANYU Customization Strengths

With 20+ years of expertise, TIANYU offers end-to-end customization:

Material Upgrades: Duplex steel (2205), Hastelloy (C276), or Inconel for extreme corrosion/heat.
Actuation Expansion: Smart electric (Modbus) or pneumatic (positioner) actuators for remote control.
Seal Flexibility: Switch between metal hard-seal and EPDM/NBR soft-seal (clean media).
Delivery: 25-day standard lead time, 18-day small-batch custom, 72-hour emergency service.
Support: Global technical centers provide lifecycle management, 48-hour spare parts, and AR-assisted maintenance.

Application

V. Application Scenarios

(A) Petrochemical: High-Temperature Steam/Oil

In refinery catalytic cracking steam lines (350℃, 4.0MPa), the metal hard-seal resists heat, and triple eccentricity prevents stem corrosion from condensate. A DN600 valve achieved 3-year leak-free operation, doubling maintenance intervals.

(B) Power: Desulfurization & Cooling Water

In power plant desulfurization slurry lines (pH 2-12, 80℃), 316L + Stellite resists corrosion, and worm gear drives large (DN800) valves. A 600MW unit saw 100,000 cycle reliability, reducing slurry leakage by 70%.

(C) Metallurgy: Blast Furnace Gas

In steel mill blast furnace gas lines (250℃, 1.6MPa, coal dust), triple eccentricity prevents clogging, and metal sealing stops gas leaks. A DN1000 valve replaced a gate valve, cutting flow resistance by 40% and energy use by 15%.

(D) Municipal: High-Temperature Heating

In city district heating networks (150℃, 1.6MPa), ductile iron resists corrosion, and metal sealing ensures long-term leakage. A DN300 valve operated winter continuously, slashing maintenance costs by 30%.

API 609 High Performance Triple Offset Metal Hard-Seal Flanged Butterfly Valve