Description

A gate valve, or sluice valve, is a linear-motion valve that uses a solid, flat, or wedge-shaped disc to open and close the fluid passage. They are available in A105, A182/F316, and A182/F304L steel. The gate rises to allow flow and lowers to block it. This design provides a full-port opening, which means there’s minimal pressure drop across the valve when it’s fully open, making it ideal for on/off or isolation service. Gate valves are not well-suited for throttling or flow regulation because the partial opening of the gate can lead to high-velocity flow, causing erosion and damage to the seat and gate.

Types of Sight Glasses

Gate valves are primarily classified by the design of their disk or gate and the movement of their stem.

• Wedge Gate Valves: The most common type, these valves use a solid or flexible wedge-shaped gate that presses against two angled seats in the valve body to form a tight seal.
• Parallel Slide Gate Valves: These use a flat gate that slides between two parallel seats. They are often used in applications where thermal expansion might be an issue, as the design is more forgiving of temperature changes.
• Knife Gate Valves: Characterized by a sharp, knife-like gate, these valves are specifically designed to cut through thick fluids, slurries, or dry bulk materials.

Norme ASME e API

The design, testing, and performance of gate valves are governed by industry standards to ensure safety and reliability.

• ASME B16.34: his standard specifies pressure-temperature ratings, materials, dimensions, and testing requirements for a wide range of valves, including gate valves. It’s the foundational standard for the design and construction of steel valves.
• API 600: This is a key standard for large, cast steel gate valves used in the petroleum.