GATE VALVES

Description:
Gate valve is using a gate or wedge type disc to fully open or fully close. The main purpose is to block fluid flow. While fluids start and stop in the pipe system, the disc moves perpendicular to the flow.

Gate valves require extremely little space along the pipe axis to restrict fluid flow. The stem and hand wheel rotate clockwise to open (CTO) or clockwise to close (CTC) in order to operate the gate valve. The body, seat, wedge, stem, gasket, hand wheel, and bonnet are the main components of a gate valve.

Brand:

AF Hydro

Size Range	3/4" to 6"
Material	SS316 / Cast Steel / Cast Steel / Forged Steel A105
Working Pressure	150# 200# 800#
Flange Connections	150# Flange End JIS10K Flange End Threaded End (NPT / BSPP) Welded End Socket Weld
Applicable Medium	General Oil, Gas & Water Applications
Temperature Range	SS316: ≤425°C Cast Iron: ≤205°C Cast Steel: ≤425°C A105: -29°C to 425°C

CATALOGUE

LITERATURE

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Different Types of Gate Valves

ANSI 150# SS316
Gate Valve

JIS 10K SS316
Gate Valve

Threaded End SS316
Gate Valve (200 PSI)

Threaded End SS316
Gate Valve (800 PSI)

ANSI 150# Cast Iron
Gate Valve

JIS 10K Cast Iron
Gate Valve

ANSI 150# Cast Steel
Gate Valve

ANSI 150# Forged Steel
Gate Valve

Threaded End Forged Steel
Gate Valve

Welded End Forged Steel
Gate Valve

Product Information of Gate Valves

1. The different types of Gate Valves:

Solid taper wedge: Because of its strength and simplicity, the solid taper wedge is the most popular and commonly used disc type gate valve. A solid wedge valve can be fitted in any location and it is suited for all type of fluids. However, it does not compensate for variations in seat alignment caused by pipe loads or thermal expansion. Leakage is most likely to occur in the disc design. Thermal locking is applied to solid wedges for use in high-temperature applications. Thermal locking occurs when a wedge is stuck between the seats and causing the metal to expand. In moderate to lower pressure temperature applications, solid wedge type gate valves are commonly used.

Flexible wedge: One piece of solid disc with a cut around the perimeter makes up a flexible wedge. The size, depth, and shape of this cut vary. A shallow, narrow cut on wedge perimeter retain strength retains and reduce flexibility. More flexibility is provided by a cast-in recess or a broader and deeper cut on the wedge perimeter. This type enhances seat alignment and also improves leak tightness. For example, heat binding improves performance. Thermal binding occurs when the wedge is stuck in the close position. When a relatively cool valve stem is put into a hot valve, the stem gets warmer and grows larger, increasing the seating force once torque is applied. The seats contact the valve wedges as the valve body cools, locking them in place. Flexible wedges are frequently utilized in steam systems. The disadvantage of the flexible wedge is that line fluid tends to collect in the disc, causing corrosion and eventually disc weakness.

Split wedge or parallel disc valve: A split wedge disc is made up of two solid sections that are held together by a specific mechanism. When one half of the disc is out of alignment, the other half of the disc hold disc is free to adjust according to seating surface. The split disc can be in the shape of a parallel disc or a wedge shape. The parallel disc are spring-loaded and interface with seats to provide bi-directional sealing. Split wedges are widely applied in the management of noncondensing gasses and liquid at normal or high temperature. Even if the valve was closed when the line was cold, the disc movement avoids thermal binding. That means when the line does not cause thermal binding when it is heated by fluid and expands.