TIANYU Heavy-Duty Industrial Knife Gate Valve: Abrasive-Resistant Cast Steel/Stainless Steel Valve with Sharp Blade Gate for Slurry, Solid-Laden Media

I. Product Overview

II. Key Attribute Specifications

A. Dimensional & Pressure-Temperature Parameters

• Nominal Diameter (Port Size): DN50 to DN1200 (2 inches to 48 inches), covering small to extra-large diameter pipelines. The full-port, unobstructed flow path minimizes pressure drop and prevents media buildup, with a flow coefficient (Cv) ranging from 60 (DN50) to 8000 (DN1200). For example, a DN300 valve can handle up to 3000 m³/h of slurry with solid content up to 40%, meeting the flow demands of mining tailings transport or wastewater treatment plants.
• Pressure Rating: PN10 (1.0MPa), PN16 (1.6MPa), and PN25 (2.5MPa)—heavy-duty pressure ratings suitable for industrial systems handling high-density media. Hydrostatic testing adheres to API 598 standards: 1.5×rated pressure for the valve shell (e.g., 3.75MPa for PN25) and 1.1×rated pressure for the seat (e.g., 2.75MPa for PN25), ensuring structural integrity and leak-tight performance under load.
• Temperature Range: -20℃ to 300℃, enabled by high-temperature-resistant materials and seals. This range covers ambient media (mining slurries, wastewater), moderately heated fluids (chemical process streams), and high-temperature applications (power plant ash handling systems).

B. Material Composition

• Valve Body & Bonnet:
  • Cast Steel (WCB, ASTM A216): Standard heavy-duty material for general industrial use, featuring tensile strength of 485–655MPa and yield strength ≥240MPa. Resists impact, vibration, and thermal stress, ideal for mining, metallurgy, and chemical industries. The surface is coated with anti-corrosive epoxy paint (ISO 12944) for outdoor or buried installations.
  • Stainless Steel (304/316, ASTM A182): Recommended for corrosive media (e.g., chemical slurries, seawater-based fluids). 304 stainless steel (18Cr-8Ni) resists mild corrosion, while 316 stainless steel (16Cr-10Ni-2Mo) enhances resistance to chlorides and sulfides—suitable for coastal or chemical processing applications.
  • Alloy Steel (WC6, ASTM A217): Optional for high-temperature (≤300℃) and high-pressure (PN25) applications, such as power plant steam-assisted systems, offering superior creep resistance and thermal stability.
• Knife Gate (Blade):
  • Stainless Steel (304/316): Standard for corrosive media, with a sharpened edge (hardness ≥45 HRC) to cut through solid-laden media. The blade is precision-ground to ensure tight sealing and efficient media cutting.
  • Alloy Steel with Stellite 6 Surfacing: Heavy-duty option for highly abrasive media (e.g., mining tailings, coal ash). Stellite 6 (cobalt-based alloy) surfacing on the blade edge increases hardness to ≥58 HRC, significantly reducing wear and extending service life.
  • Tungsten Carbide Coating: Optional for extreme abrasion (e.g., quartz sand slurries), with a hardness of ≥85 HRA, providing unmatched wear resistance.
• Valve Stem:
  • Stainless Steel (2Cr13/304): Corrosion-resistant and high-strength, with precision threading and polishing to reduce friction. Equipped with an anti-blowout design (API 600 requirement) to prevent stem ejection under pressure.
  • Alloy Steel (40CrNiMoA): For heavy-duty applications, offering enhanced tensile strength and fatigue resistance, ideal for large-diameter (DN800–DN1200) valves under high torque.
• Sealing System:
  • Metal Hard Seal (Stellite 6): Standard for abrasive media, featuring Stellite 6 surfacing on both the blade and seat. Delivers ANSI/FCI Class IV leakage performance (≤0.01% of rated flow) and withstands high temperatures and abrasion.
  • PTFE Soft Seal (Reinforced): Optional for non-abrasive, clean media (e.g., viscous fluids without particles), delivering ANSI/FCI Class VI bubble-tight sealing (-20℃ to 260℃).
  • Urethane Seal: For slurry applications requiring flexibility, resisting abrasion and maintaining sealing integrity with solid-laden media.
• Operation Components:
  • Manual Handwheel: Cast iron (HT200) with ergonomic anti-slip grip, mounted via a brass nut for torque transmission.
  • Gear Operator: Cast steel housing with precision gears, reducing operating torque by 60–70% for large-diameter valves.
  • Pneumatic/Electric Actuator: Aluminum alloy housing (IP67 protection) for automated operation, with torque output ranging from 500N·m to 5000N·m.

C. Connection & Operational Features

• Connection Type: Flanged (RF, Raised Face) as standard, complying with ASME B16.5 (Class 150/300) and ISO 7005-1. Wafer and lug connections are optional for small-to-medium diameters (DN50–DN400) in low-pressure systems. The RF flange design ensures secure gasket sealing, compatible with spiral-wound gaskets (stainless steel + graphite) for high-pressure/high-temperature service.
• Operation Modes:
  • Manual: Handwheel operation for small diameters (DN50–DN200) and low-frequency use, with optimized torque (≤300N·m for DN200 PN16).
  • Gear-Assisted: For medium-to-large diameters (DN250–DN800), gear reduction enables single-person operation, reducing torque by 60–70% (≤800N·m for DN800 PN25).
  • Pneumatic: Double-acting or spring-return (fail-safe) actuators for automated, high-frequency operation (e.g., wastewater treatment plants). Air supply pressure: 0.4–0.6MPa, cycle time: 15–60 seconds.
  • Electric: Multi-turn electric actuators with 4–20mA analog signal for modulating control or on-off operation, integrating with SCADA/DCS systems for remote monitoring.
• Structural Features:
  • Sharp Blade Gate: Tapered, sharpened edge to cut through fibers, solids, and slurries, preventing clogging and ensuring smooth closure.
  • Full-Port Flow Path: Unobstructed internal design minimizes media buildup, critical for slurry and solid-laden media.
  • Bidirectional Sealing: Reliable sealing in both flow directions, eliminating the need for check valves in bi-flow systems (e.g., pipeline bypass loops).
  • Bottom Guided Gate: Additional guiding at the bottom of the gate ensures stability and alignment, reducing wear and preventing jamming.
• Safety Features: Valve position indicator (open/closed) for visual confirmation; lockable handwheel/actuator (optional) to prevent unauthorized operation; anti-static device (optional) to discharge static electricity in dry media; pressure relief valve (optional) to prevent overpressure.

D. Certifications & Compliance

• Core Standards: API 600 (gate valves for petroleum and natural gas), ISO 10631 (knife gate valves), ASME B16.5 (flange dimensions), API 598 (valve testing and inspection), ISO 9001 (quality management system).
• Industry-Specific Certifications: CE (EU safety compliance), ATEX/IECEx (explosion-proof, optional for hazardous areas), NACE MR0175/ISO 15156 (sour service, optional for corrosive media).
• Material Certifications: ASTM A216 (WCB), ASTM A182 (304/316), ASTM A217 (WC6), ensuring material quality and traceability.

III. Feature Description

A. Sharp Knife Gate Design: Clog-Free Operation with Abrasive Media

B. Heavy-Duty Construction: Durability in Harsh Environments

• Thickened Valve Body: WCB/cast steel bodies feature reinforced walls (≥25mm for DN300 PN25) to resist external impact and internal pressure from high-density media. In construction aggregate plants, the thickened body has survived accidental impacts from heavy machinery without deformation.
• Wear-Resistant Components: Stellite 6 surfacing and tungsten carbide coatings on the blade and seat reduce wear by 70% compared to uncoated steel, extending service life from 2–3 years to 8–10 years in abrasive slurry applications.
• Corrosion Resistance: 304/316 stainless steel and epoxy coating protect against rust and chemical corrosion, making the valve suitable for coastal mining operations (seawater exposure) and chemical plants (corrosive slurries).

C. Versatile Sealing Options: Adaptability to Media Types

• Metal Hard Seal (Stellite 6): Ideal for highly abrasive, high-temperature media (e.g., coal ash, mining tailings, molten sulfur). Stellite 6’s extreme hardness and chemical inertness prevent seal wear and leakage, maintaining ANSI Class IV performance even after 10,000+ cycles.
• Reinforced PTFE Soft Seal: For clean, non-abrasive media (e.g., viscous oils, food-grade slurries without particles), delivering bubble-tight ANSI Class VI sealing. PTFE’s chemical inertness resists acids, alkalis, and organic solvents, making it suitable for pharmaceutical and food processing applications.
• Urethane Seal: Balances flexibility and abrasion resistance for general slurry applications (e.g., wastewater sludge, agricultural fertilizers). Urethane’s elasticity compensates for minor blade wear, maintaining sealing integrity while resisting particle abrasion.

D. Multiple Operation Modes: Flexibility Across Applications

• Manual Operation: Cost-effective for small diameters and remote locations (e.g., rural mining sites without power), with ergonomic handwheels ensuring easy operation.
• Gear-Assisted Operation: Reduces torque for medium-to-large diameters, enabling single-person control of DN800 valves—critical for industrial facilities with limited labor resources.
• Pneumatic Automation: Ideal for high-frequency operation (e.g., wastewater treatment plants with hourly cycle requirements), with spring-return actuators providing fail-safe protection (e.g., closing the valve during air supply loss to prevent media overflow).
• Electric Automation: Enables remote monitoring and control via SCADA/DCS systems (e.g., large-scale mining operations with centralized control rooms), with 4–20mA signals for precise flow modulation.

E. Full-Port Flow Path: Minimizing Pressure Drop & Buildup

IV. Manufacturing Processes

A. Material Inspection & Preparation

• Raw Material Verification: All materials undergo rigorous testing to ensure compliance with standards:
  • WCB/cast steel billets are tested via spectral analysis (ASTM A216) to confirm chemical composition (C: 0.25–0.35% for WCB) and ultrasonic testing (UT) to detect internal defects (porosity, cracks).
  • 304/316 stainless steel plates are verified via positive material identification (PMI) to confirm chromium (17–19% for 304) and nickel (8–11% for 304) content, ensuring corrosion resistance.
  • Stellite 6 and tungsten carbide coatings are tested for thickness (1.5–2.0mm) and hardness (≥58 HRC for Stellite 6) via hardness testing and X-ray fluorescence (XRF) analysis.
• Surface Preparation:
  • Cast components (body, bonnet) are sandblasted (ISO 8501-1) to remove scale and surface defects, improving paint adhesion and corrosion resistance.
  • Valve stems are heat-treated (quenching and tempering) to enhance strength, then polished to a surface roughness of Ra ≤0.4μm to reduce friction with packing.
  • Blade gates are precision-ground to a sharp edge (taper angle 5°–10°) and surface roughness of Ra ≤0.8μm for optimal cutting and sealing.

B. Precision Machining of Critical Components

• Valve Body & Bonnet: CNC turning and milling centers shape the body and bonnet, with internal flow paths machined to full-port dimensions (no obstructions). Flange faces are machined to flatness tolerance ≤0.05mm/m (ASME B16.5) and surface finish Ra ≤3.2μm for proper gasket seating. Seat pockets are honed to a diameter tolerance of H7 (0–+0.03mm) to ensure uniform contact with the blade.
• Knife Gate (Blade): The blade is CNC-machined from stainless steel/alloy steel, with a sharpened edge formed via precision grinding. For Stellite 6-equipped blades, TIG welding (ASTM A312) applies the alloy to the cutting edge, followed by grinding to a uniform thickness. Tungsten carbide coatings are applied via high-velocity oxygen fuel (HVOF) spraying, ensuring adhesion and uniform thickness.
• Valve Stem: Threading (trapezoidal, ISO 2904) is performed via thread rolling for wear resistance, with a thread pitch optimized for smooth operation. The stem’s upper end is machined to fit the handwheel/actuator coupling, ensuring secure torque transmission.
• Seat Components: Metal seats are CNC-machined from Stellite 6 or alloy steel, then lapped to a surface roughness of Ra ≤0.4μm to match the blade’s finish. PTFE/urethane seals are precision-cut to fit the seat profile, with retaining rings to prevent displacement during operation.

C. Assembly & Integration

• Blade & Stem Assembly: The blade is attached to the stem via a keyway and cotter pin (ISO 8750), ensuring secure torque transmission. The assembly is tested for axial runout (≤0.05mm) to prevent binding during operation.
• Seal Installation: Metal seats are press-fitted into the valve body, with spring-loading to compensate for thermal expansion and wear. PTFE/urethane seals are installed with retaining rings, ensuring uniform compression against the blade.
• Operation Component Integration: Handwheels, gear operators, or actuators are mounted to the valve via ISO 5211 adapter flanges. Gear operators are lubricated with synthetic grease (temperature range -20℃ to 150℃) to reduce friction. Pneumatic/electric actuators are calibrated to match the valve’s torque requirements (e.g., 5000N·m for DN1200 PN25).
• Final Alignment: The blade is adjusted to ensure 0.1–0.2mm preload against the seat, and the stem’s verticality is verified to ≤0.05mm/m to avoid binding.

D. Quality Testing & Certification

• Hydrostatic Testing:
  • Shell Test: The valve body is filled with water and pressurized to 1.5×rated pressure (e.g., 3.75MPa for PN25) for 30 minutes (API 598). No leakage, sweating, or deformation is allowed—test results are documented in a hydrostatic test report.
  • Seat Test: The valve is closed, and water is pressurized to 1.1×rated pressure (e.g., 2.75MPa for PN25) on the inlet side. Leakage is measured via a flow meter: ≤0.01% of rated flow for metal seals (ANSI Class IV) and ≤0.1×DN mm³/min for soft seals (ANSI Class VI).
• Operational Testing:
  • The valve undergoes 100 open-close cycles to verify smooth operation, with torque measured at each cycle (variation ≤5%). Gear-assisted and automated valves are tested for cycle time and torque consistency.
  • Blade cutting performance is tested with simulated media (e.g., fiber-rich slurry, granular solids) to ensure no jamming or dulling.
• Non-Destructive Testing (NDT):
  • Cast components are inspected via magnetic particle testing (MPI, ASTM E709) to detect surface cracks.
  • Welded components (Stellite 6 coatings) are inspected via liquid penetrant testing (PT, ASTM E165) to ensure no weld defects.
• Certification Documentation: Each valve is accompanied by a Material Test Report (MTR), hydrostatic test report, and compliance certificates (ISO 9001, CE, API 600 if applicable).

V. Product Advantages

A. Clog-Free Operation with Abrasive Media

B. Heavy-Duty Durability & Long Service Life

C. Versatility Across Industries & Media

D. Energy Efficiency & Cost Savings

E. Safety & Reliability

F. Global Standard Compliance & Compatibility

VI. Product Applications

A. Mining & Mineral Processing

• Tailings Transport: DN300–DN1200 valves with Stellite 6 blades handle mining tailings (iron ore, copper ore, gold ore) with 30–40% solid content. The sharp blade cuts through slurry, preventing clogging, while the heavy-duty body resists vibration from pipeline pumps.
• Aggregate Processing: DN100–DN400 valves control flow of crushed stone, sand, and gravel in construction aggregate plants. The full-port design prevents particle buildup, and the metal seal withstands abrasion from hard aggregates.
• Coal Mining: DN200–DN800 valves regulate coal slurry flow in washing and transport systems. 316 stainless steel bodies resist corrosion from coal-bearing water, while the knife gate cuts through coal fines and fibers.

B. Wastewater Treatment & Environmental Engineering

• Sludge Handling: DN150–DN600 valves with urethane seals control flow of wastewater sludge (organic solids, biosolids) in treatment plants. The blade’s cutting action prevents sludge clogging, and the full-port design ensures efficient sludge transfer.
• Sewage Collection: DN50–DN300 valves regulate raw sewage flow in municipal collection systems. Cast steel bodies with epoxy coating resist corrosion from sewage, while the knife gate cuts through debris (rags, plastics) that cause standard valves to jam.
• Industrial Wastewater: DN200–DN800 valves handle chemical wastewater (e.g., from textile, printing, and dyeing plants) with corrosive and abrasive components. 316 stainless steel bodies and PTFE seals resist chemical attack, ensuring long service life.

C. Chemical & Petrochemical Industry

• Slurry Processing: DN100–DN500 valves control flow of chemical slurries (e.g., lime slurry, alum slurry) in water treatment and chemical manufacturing. Stellite 6 seals withstand abrasion and chemical corrosion, maintaining leak-tight performance.
• Molten Sulfur Handling: DN80–DN200 valves with alloy steel bodies and metal seals handle molten sulfur (120–150℃) in petrochemical plants. The heavy-duty construction resists high temperatures, and the knife gate prevents sulfur solidification-related clogging.
• Corrosive Fluids: DN50–DN400 valves with 316L stainless steel bodies handle corrosive media (e.g., hydrochloric acid slurry, sodium hydroxide solution). PTFE seals ensure chemical inertness, preventing media contamination.

D. Pulp & Paper Industry

• Pulp Transport: DN200–DN800 valves with sharp blades handle wood pulp (fiber-rich slurry) in paper mills. The blade cuts through pulp fibers, preventing clogging in pipelines and tanks. 316 stainless steel bodies resist corrosion from pulp bleaching chemicals (chlorine, hydrogen peroxide).
• Black Liquor Handling: DN150–DN600 valves regulate black liquor flow (viscous, fiber-laden) in kraft pulp mills. Heavy-duty alloy steel bodies withstand high pressure and temperature (≤200℃), while the metal seal resists abrasion from liquor solids.

E. Power Generation

• Ash Handling: DN300–DN1000 valves with Stellite 6 blades control coal ash slurry flow in thermal power plants. The blade cuts through ash particles, preventing clogging in ash transport pipelines. The full-port design minimizes pressure drop, reducing pump energy consumption.
• Flue Gas Desulfurization (FGD): DN200–DN800 valves handle limestone slurry (abrasive, alkaline) in FGD systems. 316 stainless steel bodies resist corrosion from limestone, while the knife gate prevents slurry clogging in spray towers.

F. Food & Beverage Industry

• Viscous Food Slurries: DN50–DN200 valves with PTFE seals handle food-grade slurries (e.g., tomato paste, chocolate, fruit puree) without particles. The soft seal ensures bubble-tight sealing, meeting FDA (21 CFR 177.1550) and EU (EC 1935/2004) food safety standards.
• Wastewater Handling: DN100–DN300 valves regulate food processing wastewater (e.g., from meatpacking, dairy plants) with organic solids. The knife gate cuts through food debris, preventing clogging, while the cast steel body resists corrosion from cleaning chemicals.