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 |
| PN | DN | Size(mm) |
| L | D | D1 | D2 | B | N-φ | H |
| 1.6MPa | 25 | 160 | 115 | 85 | 65 | 14 | 4-14 | 275 |
| 32 | 180 | 135 | 100 | 78 | 16 | 4-18 | 280 |
| 40 | 200 | 145 | 110 | 85 | 16 | 4-18 | 330 |
| 50 | 230 | 160 | 125 | 100 | 16 | 4-18 | 350 |
| 65 | 290 | 180 | 145 | 120 | 18 | 4-18 | 370 |
| 80 | 310 | 195 | 160 | 135 | 20 | 8-18 | 400 |
| 100 | 350 | 215 | 180 | 155 | 20 | 8-18 | 415 |
| 125 | 400 | 245 | 210 | 185 | 22 | 8-18 | 460 |
| 150 | 480 | 280 | 240 | 210 | 24 | 8-23 | 510 |
| 200 | 550 | 335 | 295 | 265 | 26 | 12-23 | 710 |
| 250 | 650 | 405 | 355 | 320 | 30 | 12-25 | 786 |
| 300 | 750 | 460 | 410 | 375 | 30 | 12-25 | 925 |
Types of Gate Valves
There are three ways to classify the gate valve.
Types of Disk
Solid taper wedge
Flexible wedge
Split wedge or Parallel disks Valve
Types of Body Bonnet Joint
Screwed Bonnet
Bolted-Bonnet
Welded-Bonnet
Pressure-Seal Bonnet
Types of Stem movement
Rising Stem or OS & Y Type (Outside Stem and Screw Type)
Non-rising Stem type
Gate Valve Applications
Gate valves are used in almost all fluid services such as air, fuel
gas, feedwater, steam, lube oil, hydrocarbon, and all most any
services.
Some special gate valve is used in slurry and powder product also
such as knife gate valve
Advantages of Gate Valve
Gate valve provides good
Pressure drop during operation is very less.
Most of the gate valve can be used as bi-directional
They are suitable for high pressure and temperature application and
required less maintenance
Types of gate valve based on body, bonnet connection
1st is screwed bonnet: This is the simplest design available and it is used for
inexpensive valves.
2nd is bolted-bonnet: This is the most popular design and used in a large number of gate
valves.
This requires a gasket to seal the joint between the body and
bonnet.
3rd is Welded-Bonnet: This is a popular design where disassembly is not required. They
are lighter
in weight than there bolted-bonnet counterparts.
4th one is Pressure-Seal Bonnet: This type is used extensively for high-pressure high-temperature
applications. The higher the body cavity pressure, the greater the
force on the gasket in a pressure -seal valve.
