What is Gate Valve?
A gate valve can be defined as a type of valve that used a gate or wedge type disk and the disk moves
perpendicular to flow to start or stop the fluid flow in piping.
A gate valve is the most common type of valve used in any process plant. It is a linear motion valve used
to start or stop fluid flow. In service, these valves are either in a fully open or fully closed position.
When the gate valve is fully open, the disk of a gate valve is completely removed from the flow. Therefore
virtually no resistance to flow. Due to this very little pressure drops when fluid passes through a gate valve.
To achieve proper sealing, when the valve is fully closed, 360° surface contact is required between disk and seats.
Gate valves should not be used for regulation or throttling of flow because accurate control is not possible.
The high velocity of the flow in the partially open valve may cause erosion of the disc and seating surfaces
and also creates vibration and noise.
| Valve Type | CS / SS GATE VALVE - FL / BW |
| Design Std | BS EN ISO 10434 [BS 1414] / API 600 / API 602 / API 603/ASME B16.34 |
| Size Range | 40 DN to 400 DN [1 1/2” to 16”] |
| Body | [CS - ASTM A 216 Gr. WCB] [SS - ASTM A 351 Gr.CF8 / CF8M] |
| Trim | AISI 410 / 304 / 316 |
| Seat / Wedge | 13% Cr. Steel / AISI 410 / 304 / 316 |
| Design Features | Bolted Bonnet, OS & YT, HW & Gear operated |
| Prorating | ASME - Class 150 / 300 / 600 |
| Face to Face | ASME B 16.10 / EN 558 -1 / API 6D |
| End Connection | Flanged | ASME B16.5, CLASS 150 / 300 / 600 |
| Butt weld | ASME B16.25 |
| Testing Std. | BS EN 12266 - 1 [BS 6755-1] / API 598 |
| Optional | Lantern Ring / indicator & Locking Device/ Renewable Seat / Stellite Hard facing / Jacketed Provision / RTJ Flanges / By Pass Arrangement / Higher Sizes / Special MOC: Austenitic and Duplex Stainless Steels |
Types of Gate Valves
There are three ways to classify the gate valve.
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Types of Disk
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Solid taper wedge
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Flexible wedge
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Split wedge or Parallel disks Valve
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Types of Body Bonnet Joint
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Screwed Bonnet
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Bolted-Bonnet
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Welded-Bonnet
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Pressure-Seal Bonnet
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Types of Stem movement
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Rising Stem or OS & Y Type (Outside Stem and Screw Type)
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Non-rising Stem type
Gate Valve Applications
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Gate valves are used in almost all fluid services such as air, fuel gas, feedwater, steam, lube oil, hydrocarbon, and all most any services.
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Some special gate valve is used in slurry and powder product also such as knife gate valve
Advantages of Gate Valve
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Gate valve provides good
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Pressure drop during operation is very less.
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Most of the gate valve can be used as bi-directional
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They are suitable for high pressure and temperature application and required less maintenance
Split wedge or Parallel disks Gate Valve
Split wedge Disk consists of two solid pieces and holds together with the help of a special mechanism. You can see the same in images. In case, one-half of the disk is out of alignment; the disk is free to adjust itself to the seating surface. The split disk can be in a wedge shape or a parallel disk type.
Parallel disks are spring-loaded, so they are always in contact with seats and give bi-directional sealing. The split wedge is suitable for handling noncondensing gasses and liquids at normal and high temperatures.
Freedom of movement of the disk prevents thermal binding even though the valve may have been closed when a line is cold. This means when a line is get heated by fluid and expand it does not create thermal blinding.
