Welded Parallel Gate Valve
Overview
The Welded Parallel Gate Valve is a heavy-duty industrial valve designed for permanent installation in high-integrity piping systems. Unlike flanged valves, its welded ends eliminate potential leak points, making it ideal for hazardous or high-value fluid services. These valves are engineered for full open/close operation rather than flow modulation. Their parallel gate design uses two parallel discs that separate against seat rings when opening, reducing wear compared to wedge-type gates.
Structure and Working Principle
The valve consists of a one-piece welded body, parallel gate discs, seat rings, stem, and bonnet assembly. When the handwheel or actuator rotates the stem, the gate moves linearly upward/downward between the seat rings. In the closed position, system pressure pushes the gate discs outward against the seats, creating a metal-to-metal seal. The welded construction ensures body integrity even under thermal cycling or pressure fluctuations common in power plants and refinery applications.
Key Features
1) Zero-leakage welded design meets API 600/API 6D standards for critical services. 2) Parallel gate mechanism reduces operating torque by 30-40% compared to wedge gates. 3) Available in pressure classes from ASME 150 to 2500. Special variants include cryogenic versions for LNG (-196°C) and high-temperature alloys for boiler feed applications (up to 650°C). Anti-blowout stems and fire-safe designs per API 607 are optional for hazardous environments.
Application Areas
Primary applications include: 1) Mainline isolation in oil/gas transmission pipelines (API 6D compliance required). 2) Power plant steam systems (ASTM A182 F91/F92 bodies). 3) Chemical processing of corrosive media (lined valves with PTFE/Alloy 20). These valves are specified where leakage cannot be tolerated, such as offshore platforms, sour gas service (NACE MR0175), or nuclear auxiliary systems. Their welded ends are preferred over flanges in subsea and buried pipeline installations.
Maintenance and Precautions
Being welded-in valves, they require minimal maintenance but need proper installation: 1) Weld procedures must follow ASME B31.3 with PWHT if needed. 2) Avoid misalignment stresses during piping installation. For maintenance, most designs allow seat replacement via top-entry without removing the valve body. Regular lubrication of stem threads and annual sealing tests (per API 598) are recommended. Never use these valves for throttling - the parallel gate design causes severe erosion at partial openings.
B2B Procurement Guide
Key specifications to confirm: 1) Pressure-temperature rating matching system requirements. 2) Material compatibility (NACE for H2S, chloride stress cracking resistance). 3) End preparations (bevel type per ASME B16.25). Leading manufacturers include Velan, Cameron, and L&T Valves. Lead times for custom valves can exceed 12 weeks. For cost efficiency, consider standard ASME B16.34 designs rather than proprietary patterns unless project specs dictate otherwise.
Related Manufacturers
- 主营：灭菌器、安全阀、氧气储罐、高压切断阀
- 主营：螺旋输送机、刮板输送机、粉尘加湿机、斗式提升机、管式螺旋输送机、通风蝶阀、无轴螺旋输送机、插板阀、星型卸料器、电动插板阀、手动插板阀、埋刮板输送机、气动插板阀
- 主营：布袋除尘器、催化燃烧设备、pp喷淋塔、斗式提升机、活性炭吸附箱、滤筒除尘器、电捕焦油器、除尘骨架、危废间、除尘布袋、锅炉布袋、电磁脉冲阀、光氧净化器、旋风除尘器、脉冲除尘器、塑烧板除尘器、单机布袋除尘器、焊烟净化器、星型卸料器、螺旋输送机、危废间储存间、等离子油烟净化器、打磨除尘工作台、粉尘加湿机
- 主营：--
- 主营：--
- 主营：RTO废气焚烧炉、催化燃烧设备、布袋除尘器、斗式提升机、刮板输送机、废气焚烧炉、沸石转轮、手动通风蝶阀、喷淋塔、催化燃烧一体机、滤筒除尘器、危废间、油烟净化器、湿电除尘器、星型卸料器、活性炭吸附箱、粉尘加湿搅拌机、焊烟净化器、光氧催化净化器、打磨除尘平台、螺旋输送机、光氧活性炭一体机、波纹管补偿器、通风蝶阀、工业除尘器
- 主营：球阀、蝶阀、截止阀、闸阀、止回阀、平衡阀、调节阀、安全阀、呼吸阀、阻火器、疏水阀、减压阀、柱塞阀、放料阀、过滤器、隔膜阀、管夹阀、排气阀、排泥阀、旋塞阀、氧气阀、低温阀、铜阀门
- 主营：矿用沟槽阀门、油田阀门、卡箍阀、高压沟槽闸阀、平板闸阀、角式截止阀、立式止回阀、泥浆闸阀、阀套式排污阀、节流截止阀、API6A阀门、高低压球阀、高压止回阀、节流截止放空阀
- 主营：Z63Y平行式焊接闸阀、磁悬浮风机
- 主营：气动法、减压阀、气动薄、刀闸阀、汇流排、德国top、排污阀、减压器、电磁阀、截止阀、疏水阀、r72低压、池底阀、止回阀、对夹蝶、平衡阀、二阀组、安全阀、流程泵、帽防爆、逆止阀、过滤器、脉冲阀、冷凝泵、进口阀门
- 主营：高压球阀、高压电磁阀、不锈钢电磁阀、Z63Y平行式焊接闸阀、蒸汽减压阀、蒸汽疏水阀、锻钢截止阀、进口隔膜泵、不锈钢球阀、电动调节阀
- 主营：沟槽球阀、节流截止阀、泥浆阀、高压沟槽闸阀、平板闸阀、高压平板闸阀、矿用阀门、API6A阀门、油田阀门
- 主营：卸料器、卸料阀、卸灰阀、刀闸阀、电动刀闸阀、鄂式闸门、泄爆阀、旋转阀、插板阀、关风机、叶轮给料机、放料阀、电动锁气器、百叶阀、双层电动翻板阀、闸板阀、翻板阀、回转阀、排灰阀、扇形闸门、通风蝶阀、气动双层翻板阀、双层翻板阀、星型卸料器、刮板卸料器
- 主营：气动执行器、气动球阀、气动蝶阀、气动闸阀、气动截止阀、气动调节阀
- 主营：直通式双向闸阀、烟道波纹补偿器
- 主营：泄爆阀、提升机、除尘器、重锤式翻板阀、插板阀、通风蝶阀、法兰蝶阀、绞龙输送机、重锤翻板阀、三通分料器、刮板输送机、加湿搅拌机、电捕焦油器、水渠阀门、卸料器、棒条阀、软连接
- 主营：陶瓷双闸板、陶瓷球阀、陶瓷摆动阀、不锈钢刀闸阀、方形闸门、铸铁镶铜闸门、盲板阀、螺旋闸门、水力控制阀、调流调压阀、三开插板阀、偏心半球阀
- 主营：阀门耐磨、陶瓷旋启、陶瓷球阀、陶瓷刀闸阀、手动法兰、陶瓷摆动、双闸板阀、圆顶阀充气、三通换向阀、陶瓷半球阀
- 主营：料浆阀、电磁阀、截止阀、柱塞闸阀、平板闸阀、黄铜闸阀、止回阀、过滤器、呼吸阀、出料阀、防止器、调节球阀、直通球阀、手轮法兰、气动蝶阀、铸铁法兰、清管球阀、快装蝶阀、快装球阀、碳钢法兰、单座调节阀、电磁流量计、阻汽排水阀、遥控浮球阀、丝扣柱塞阀
- 主营：黄铜铸件、铜套、铜瓦、防爆钳子、铜丝母、铜螺母、铜涡轮、铜线夹、铜铸件、铸铜件、铜件、铜件定制、铜件加工
- 主营：高温高压球阀、高温高压蝶阀、调节阀、闸阀、刀闸阀、排气阀、平衡阀、止回阀、针型阀、高温高压电站阀、气动角座阀、截止阀、陶瓷阀
- 主营：执行器、切断阀、气动阀门、气动闸阀、电动闸阀、自力式调节阀、笼式调节阀、气动球阀、气动蝶阀、气动截止阀、电动阀门、电动球阀、电动截止阀、调节阀、套筒调节阀、减压阀、电磁阀、限位开关、过滤减压阀、电动执行器
- 主营：呼吸阀、阻火器、陶瓷阀、穿透式刀闸阀、球阀
- 主营：切断阀、排污阀、电动阀、刀闸阀、电磁阀、止回阀、柱塞阀、手动刀、泄爆发、排气阀、调节阀、旋塞阀、气动刀、截止阀、持压阀、安全阀、排灰阀、管力阀、液动角、保温阀、直通篮、料浆阀、扩浆阀、对夹蝶、排污泵
- 主营：选粉机设备、滤筒除尘器、拌湿机设备、蓄热式焚烧炉、布袋除尘器、油烟处理设备、废气处理设备、催化燃烧设备、电捕焦油器设备、除尘器布袋、喷淋塔、卸料器、插板阀
- 主营：对夹蝶阀、气动蝶阀、法兰蝶阀、明杆闸阀、软密封闸阀、中线蝶阀、迈尔特金属、不锈钢球阀、蝶形止回阀、阀门、球阀、蝶阀、止回阀、逆止阀
- 主营：弧形阀、刮板机、厂双层、电动鄂式闸阀、手动刀、正压星、链条斗、双向压、防卡星、粉空气、扇形阀、调节阀、鸟笼子、异型阀、圆口星、卸料机、下料阀、输送机、百叶阀、拆卸星、315空气、挡板门、铸铁星、拉链机、防爆星、制砂机