KFTE offers the standard product line of API 600 Cast Steel Gate Valves in a wide variety of carbon steel, low and medium allow materials, which can be used in combination with listed API-600 trims. Cast Steel Gate Valves are used in very specific applications: water distribution, gas oil, steam, petrochemical and petroleum industries and gas systems. Combining high toughness, hardness and tensile strength with impact strength, cast steel gate valves are commonly used for high-temperature and high-pressure applications in a variety of industries.
Body:
Function: Main casing that contains internal parts and connects to the pipeline.
Material: Typically cast iron, cast steel, or alloy, chosen for durability and pressure resistance.
Design: Features flanged, threaded, or welded ends for pipeline connection. The internal flow path is straight to minimize pressure drop.
Bonnet:
Function: Seals the valve body, housing the stem and packing.
Attachment: Bolted, screwed, or welded to the body. Includes a gasket for a leak-proof seal.
Gate/Wedge:
Function: Moves perpendicularly to the flow to block or allow passage.
Types: Solid wedge (common), flexible wedge (for thermal expansion), or split wedge (for tight seals). Materials match the body or are upgraded for corrosion resistance.
Stem:
Function: Transmits motion from the actuator to the gate.
Types:
Rising Stem: Visible vertical movement; threads outside the valve.
Non-Rising Stem: Threads inside; stem doesn’t ascend. Common in limited-space applications.
Actuator:
Function: Operates the stem. Includes a handwheel (manual), gearbox (for high torque), or automated systems (electric/pneumatic).
Seats:
Function: Sealing surfaces where the gate contacts to stop flow. Typically integrated into the body or replaceable rings.
Material: Often bronze, stainless steel, or hardened alloys for wear resistance.
Packing Gland/Stuffing Box:
Function: Seals the stem exit point to prevent leaks.
Components: Packing material (graphite, PTFE) compressed by a gland flange or follower.
Yoke:
Function: Connects the bonnet to the actuator, providing structural support for the stem.
End Connections:
Types: Flanged (common in cast valves), threaded, or welded, matching pipeline specifications.
Bolts/Nuts and Gaskets:
Function: Secure the bonnet to the body and ensure leak-proof seals.
1. By Wedge Design
Solid Wedge: A single-piece, rigid wedge ideal for high-temperature or turbulent flow applications. Commonly used in steam systems.
Flexible Wedge: Features a cut around the perimeter to allow slight flexing, accommodating pipe distortion or thermal expansion.
Split Wedge (Double Disc): Two-piece design that self-aligns to uneven seating surfaces, suitable for non-condensing gases and liquids.
Parallel Slide (Parallel Disc): Uses two spring-loaded parallel discs to maintain sealing contact, often found in steam systems.
2. By Bonnet Design
Screwed Bonnet: Simple, low-cost design for low-pressure applications (e.g., residential plumbing).
Bolted Bonnet: Features a gasket and bolts for medium-to-high-pressure systems (common in industrial settings).
Welded Bonnet: Permanently sealed by welding, used in high-pressure/temperature environments (e.g., oil refineries).
Pressure-Seal Bonnet: Relies on system pressure to enhance sealing, ideal for very high-pressure systems (e.g., power plants).
3. By Stem Movement
Rising Stem (OS&Y): The stem rises visibly when opened, allowing easy position verification. Common in above-ground installations.
Non-Rising Stem (NRS): The stem rotates internally, saving vertical space. Used in confined areas like underground systems.
4. Application-Specific Types
Knife Gate Valve: Thin, sharp gate to cut through thick fluids or slurries (e.g., wastewater treatment).
Through-Conduit Gate Valve: Full-bore design for pipeline pigging, ensuring minimal pressure drop (common in oil/gas pipelines).
Slab Gate Valve: Single-piece gate with a bore hole, used in crude oil pipelines for tight sealing.
