I. Working Principle
The stainless steel flanged gate valve controls fluid flow through vertical movement of the gate (disc) via handwheel rotation or actuator:
Open state: Gate rises to valve chamber top, allowing unobstructed flow.
Closed state: Gate descends to seat, achieving complete fluid shutoff.
Sealing surfaces remain perpendicular to flow direction, relying on tight gate-to-seat contact.
II. Core Structure
Body: Main pipeline connection component bearing fluid pressure.
Gate:
Wedge type (single/double): Self-sealing via wedge angle for high-P/T applications.
Parallel type: Simplified structure with repairable sealing surfaces.
Seat: Forms sealing interface with gate (material compatibility required).
Stem: Transmits torque from handwheel to gate.
Sealing systems: Includes stuffing box (stem leakage prevention) and bonnet seals.
III. Key Characteristics
Advantages:
Low fluid resistance (full-bore design minimizes pressure drop)
Superior sealing performance
High temperature/pressure tolerance (wedge-type)
Bidirectional flow capability
Disadvantages:
Slow operation (vertical travel required)
Complex maintenance (multiple components)
Seal surface wear from frequent cycling
IV. Applications
Oil & Gas: Transmission pipelines, refineries
Chemical: Corrosive fluid handling
Power: Boiler feedwater/steam lines
Water Treatment: Municipal/industrial plants
Marine & Metallurgy: Ship piping, furnace cooling
V. Selection Criteria
Media: Corrosive fluids demand SS/alloy steel.
Pressure: Match PN rating to system requirements.
Temperature: Consider thermal expansion design.
Sealing: Wedge-type preferred for critical sealing.
Actuation: Manual/electric/pneumatic options.
VI. Maintenance & Troubleshooting
Routine checks: Seal wear inspection, stem lubrication.
Common failures:
Leakage: Reseal or replace damaged components.
Operation issues: Remove obstructions/realign bent stems.