III. Product Features

• Knife Edge Shear Capability: The gate’s sharp, precision-ground edge creates a shearing effect when closing, cutting through fibers (e.g., sewage hair), dust agglomerates (e.g., cement clumps), or small particles (e.g., sand)—a critical advantage over standard gate valves, which often clog with such media. This eliminates the need for frequent disassembly and cleaning, reducing maintenance downtime by 40-60%.
• Wafer Flange Compactness: The wafer design clamps directly between pipeline flanges, requiring no dedicated bolt holes in the valve body. This reduces overall valve weight (DN100 model weighs ~35kg, vs. 50kg for full-flange gate valves) and saves installation space—ideal for tight pipelines in factories or municipal pump stations.
• Dual Seal Versatility: PTFE soft seals deliver API 598 Class VI bubble-tight shutoff for clean media (e.g., drinking water), preventing leakage and water waste. Metal hard seals (SS304) withstand abrasion from particles (e.g., mining slag) and high temperatures (up to 200℃), maintaining sealing integrity for 5,000+ cycles.
• Precise Electric Control: The actuator’s DC 4-20mA signal compatibility enables proportional flow regulation—critical for applications like sludge dosing in wastewater treatment or dust flow control in cement plants. Modbus RTU communication allows integration into SCADA systems, enabling remote monitoring and adjustment (e.g., from a central control room).
• Wide Voltage Compatibility: AC 220V/110V and DC 24V options ensure the valve works in global markets, from North American (110V AC) to European (220V AC) or industrial (24V DC) power systems—no need for additional voltage converters.
• Emergency Manual Override: A built-in mechanical handle allows manual operation during power outages, preventing process shutdowns in critical applications (e.g., gas pipeline emergency shutoff or water supply for fire protection).
• WCB Material Durability: WCB cast steel undergoes normalizing heat treatment (850-900℃, air-cooled) to relieve internal stress, enhancing impact resistance and preventing cracking under pressure. The material’s smooth internal surface minimizes media turbulence, reducing wear on the gate and seals.

IV. Manufacturing Process

• 1. Raw Material Inspection: WCB cast steel ingots, SS304 stems, and 1.4529 gate blanks undergo rigorous testing. Chemical composition analysis (via optical emission spectrometry) verifies WCB’s carbon content (0.25-0.35%) and alloy elements (manganese, silicon) to meet ASTM A216. Mechanical testing (tensile, hardness) ensures WCB’s tensile strength exceeds 485MPa, while 1.4529 gates are checked for corrosion resistance via salt spray testing (72 hours).
• 2. WCB Body Casting: The valve body is produced via sand casting— a cost-effective method for complex shapes. Molten WCB (1500-1550℃) is poured into precision molds, then cooled slowly to prevent shrinkage defects. After demolding, the body is shot-blasted to remove sand residue and achieve a smooth surface (Ra ≤2.5μm).
• 3. Heat Treatment: WCB bodies undergo normalizing heat treatment to improve material toughness. Bodies are heated to 880℃, held for 1 hour, then air-cooled to room temperature—this reduces internal stress by 60% and prevents cracking during machining.
• 4. CNC Machining:
  • Body Machining: The valve’s internal flow path and wafer flange faces are machined using 3-axis CNC mills. Flange faces are ground to ASME B16.5 Class 150 standards, ensuring flatness (tolerance ±0.05mm) for tight clamping between pipeline flanges.
  • Gate Machining: 1.4529 gate blanks are CNC-turned to shape, then the knife edge is ground to a 30° angle (for optimal shearing) using a precision grinder. The gate’s surface is polished to Ra ≤0.8μm to minimize friction with seals.
  • Stem Machining: SS304 stems are turned to precise diameters (tolerance ±0.02mm) and threaded at the top for connection to the electric actuator. The stem’s surface is chrome-plated to enhance wear resistance.
• 5. Seal Assembly: Seals are installed based on application:
  • PTFE Soft Seals: PTFE rings are molded to fit the valve body’s seal groove, then bonded with high-temperature adhesive to prevent displacement during operation.
  • Metal Hard Seals: SS304 seal rings are press-fitted into the body, then welded around the edges for permanent attachment. The seal face is ground to match the gate’s contour, ensuring uniform contact.
• 6. Actuator Integration: The electric actuator (DC 24V/AC 220V) is mounted to the valve bonnet via ISO 5211 brackets. The actuator’s drive shaft is aligned with the valve stem, then secured with a coupling. Torque calibration is performed to ensure the actuator applies enough force to open/close the gate (without overloading the motor)—typically 50-100 N·m for DN100 models.
• 7. Control System Testing: The actuator’s control interface (4-20mA, Modbus RTU) is connected to a test bench. Signal accuracy is verified: a 4mA input should fully open the gate, while 20mA closes it, with ±0.8% deviation allowed. Modbus communication is tested for data transmission (e.g., gate position, fault alerts) to ensure compatibility with SCADA systems.
• 8. Pressure and Leakage Testing:
  • Shell Test: The valve body is filled with water and pressurized to 1.5×PN16 (2.4MPa) for 10 minutes. No visible leakage or body deformation is allowed—tested using ultrasonic leak detectors for precision.
  • Seat Test: Air (0.6MPa) is applied to the valve inlet; leakage from the seat is measured to meet API 598 Class IV (≤0.15mL/min for DN100). For PTFE seals, the test uses water (1.1×PN16) to verify bubble-tight shutoff.
• 9. Surface Treatment: WCB bodies are painted with two coats of epoxy resin (gray or blue) to prevent rust. The paint is cured at 80℃ for 2 hours, forming a scratch-resistant layer (hardness ≥2H) that withstands outdoor exposure.
• 10. Final Assembly and Inspection: The manual override handle is installed, and the valve undergoes a full 50-cycle open/close test to verify smooth operation. Critical dimensions (flange thickness, gate stroke) are measured using a coordinate measuring machine (CMM) to ensure compliance with design standards. Each valve is labeled with serial number, material, and pressure rating for traceability.