Recently, Dervos Valve helped a client in Hungary overcome a common challenge in industrial steam systems: how to safely isolate high-temperature pipelines without leakage or downtime. Operating with saturated steam at around 250°C and exposed to temperatures as low as -39°C, the client’s system demanded a solution that was both robust and reliable. Traditional valves often failed to maintain a tight seal under such conditions, and conventional isolation methods required depressurizing the line, increasing downtime and operational risk. To address these challenges, Dervos supplied a DN400 PN40 sliding line blind valve, engineered specifically for the project’s harsh conditions. The valve’s sliding blind mechanism allows operators to switch between flow and isolation positions without depressurizing the system, enhancing safety and efficiency during maintenance. Built with forged 20GML steel and a metal-to-metal stainless steel sealing structure, the valve delivers reliable performance under both high-temperature steam and extreme outdoor climates. Its full-bore design minimizes flow resistance, while the worm gear manual actuator ensures smooth and controlled operation even at large sizes and high pressure ratings. Safety features such as anti-misoperation devices and protective blind plate structures further reduce the risk of errors during handling. Since installation, the valve has enabled leak-free operation, safer maintenance procedures, and stable performance in extreme temperatures. Designed for a service life exceeding 30 years, it provides a long-term, low-maintenance solution, giving the client confidence in their steam system’s reliability and safety. This project highlights how a carefully engineered sliding line blind valve can solve critical isolation challenges in high-temperature steam applications, combining operational safety, durability, and efficiency in one solution.
In industrial piping systems, gate valves are generally considered low-resistance isolation valves. When the valve is fully open, the gate is completely withdrawn from the flow path, allowing the fluid to pass through with minimal obstruction. However, from a strict engineering perspective, not all gate valves are classified as full port valves. If the seat bore is equal to or very close to the pipeline internal diameter, the flow experiences little or no restriction. In this case, the valve can be considered full port (or near full port). This design is commonly used in oil and gas pipelines, water transmission systems, and other applications where low pressure drop is required. If the seat bore is slightly smaller than the pipe internal diameter, a minor flow restriction will occur inside the valve. In such cases, the valve is more accurately described as reduced bore. This configuration is more common in smaller sizes or cost-optimized valve designs. In engineering practice, a simple selection logic can be applied: ● If the system requires minimum flow resistance or pipeline pigging, the valve bore must match the pipeline diameter. ● If the valve is used for general isolation purposes, most standard gate valves can already meet the required flow capacity. Therefore, a concise conclusion can be drawn: Gate valves are typically close to full port designs, but whether they are truly full bore depends on whether the seat bore equals the pipeline internal diameter. QA Q1: Are gate valves always full bore?Not necessarily. If the seat bore equals the pipe internal diameter, the valve can be considered full bore. If it is slightly smaller, it is classified as reduced bore. Q2: Why do gate valves have relatively low flow resistance?When the valve is fully open, the gate is completely removed from the flow path, allowing the fluid to pass through in a nearly straight line, which results in low pressure drop. Q3: Are gate valves suitable for high-flow pipelines?Yes. If the system requires low pressure drop, gate valves are commonly used. Q4: Is the concept of full port the same for gate valves and ball valves?Not exactly. For ball valves, the bore size is determined by the ball port diameter, while for gate valves, it is mainly determined by the seat bore diameter.
Large diameter ball valves are commonly used in industries such as petroleum and chemical processing, power generation, long-distance pipeline transportation, and large-scale water treatment systems. If installation is not performed correctly, it may lead to sealing leakage, valve jamming, or structural stress damage. Therefore, proper installation practices are essential to ensure long-term stable operation. 1. Pre-installation Inspection If pre-installation inspection is insufficient, operational failures are more likely to occur during service. First, inspect the valve body for transportation damage. If scratches, impact marks, or deformation are found on the valve body or sealing surfaces, installation should be stopped and the supplier should be contacted. Next, verify valve model, pressure rating, and connection standards. If the system design pressure does not match the valve pressure class, operational safety risks may occur. For example, if a low-pressure class valve is mistakenly used in a high-pressure pipeline system, the valve body may experience plastic deformation under water hammer impact. It is also necessary to check the condition of the ball surface and sealing rings. If there are scratches on the ball surface, sealing performance will be reduced. This is especially critical in gas transmission systems where micro-leakage is more likely. 2. Installation Direction Large diameter ball valves usually have a flow direction marking. If the installation direction is incorrect, the following problems may occur: If the fluid flow direction matches the design direction, the operating torque will remain more stable. If the valve is installed in reverse, the stem may experience increased mechanical load, which will accelerate stem wear during long-term operation. For double-seal bidirectional ball valves, although bidirectional flow is allowed, installation according to the marked flow direction is still recommended to ensure more uniform sealing stress distribution. In high-temperature or steam systems, if the installation direction is incorrect, thermal expansion may accelerate sealing ring aging. 3. Pipeline Stress Control Large diameter ball valves are heavy. If installed without proper support, additional bending moments may be transferred to flange connections. If pipeline systems experience axial displacement, pipeline supports should be installed for segmented fixation. If support structures are not provided, the valve body may bear long-term gravitational tensile load, eventually causing flange seal failure. It is generally recommended to install independent supports on both sides of large diameter ball valves. If the pipeline system is subject to thermal expansion and contraction, expansion compensation devices must be installed; otherwise, sealing surfaces may gradually fail. 4. Bolt Tightening Process Flange connections of large diameter ball valves usually ...
16" 900LB ball valve is made according to API 6D standard. The valve body is made of A350 LF2. It has the structural characteristics of fully welded, fixed ball and full bore. Its connection mode is BW. And it has turbine operation mode.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
A350 LF2Method of Operation:
Turbine OperationProduct Description
|
Type |
Ball Valve |
|
Size |
16" |
|
Pressure |
900LB |
|
Connection |
BW |
|
Operation |
Turbine Operation |
|
Body Material |
A350 LF2 |
|
Design Norm |
API 6D |
|
Pressure/temperature |
ASME B16.34 |
|
Face to face |
API 6D |
|
BW END |
ASME B16.25 |
|
Test & Inspection Code |
API 6D |
|
Temperature |
-29 ~ 121°C |
|
Applicable Medium |
Water, Oil and Gas |
Features
1. The valve body structure is welded as a whole, without external leakage;
2. Easy to install, long-term reliable operation.
Technical Drawing
Dimension Checking
Pressure Testing
Painting
Nameplate & Packing
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With butt weld end and gearbox, the fully welded ball valve is designed per ASME B16.34. The one piece ball valve has trunnion type ball, antistatic design and full port structure. Quick Detail Type Ball Valve Size 10" Pressure ANSI 300 Construction Trunnion Type, One Piece Body, Full Bore, Fully Welded Connection Butt Weld (BW) Operation Gearbox Body Material Forged Steel A105 Design API 6D Pressure & Temp ASME B16.34 Face to Face ASME B16.10 End Connection ASME B16.25 Inspection API 598 Temperature Range -29℃~+125℃ Media W.O.G Related Knowledge What is a fully welded ball valve? What is the benefit and advantage of a fully welded ball valve? A fully welded ball valve is welded after forging without any bolted connection on the body. Compared with flanged ball valve, it features in maximum strength at minimum weight. The design of the valve gives it advantage: -Overall small size and light weight -Fewer leak paths on the body -High machining precision of ball part -High resistance to external and internal pressure and strength Our Service Dervos customer service is one of our biggest competitive advantages. In Dervos, we provide- 1.Quotation within 24 hours or no later than 3 days This will let you meet the quotation submission deadline and enhance your working efficiency 2.Weekly status report of your order In this way, you will have a clear picture of your order. You do not need to waste time on pushing us for status update 3.An 18-month warranty period A warranty certificate will issued after shipment and you will not have any concern after buying valves. 4.Solutions to complaints within 3 days Quick and responsible actions to complaints will protect your reputation and reduce the financial loss as much as possible.
The 20 inch metal seated ball valve is designed for high temperature application or application with solid particulate. The valve has welded body, RF flange connection, bare stem for actuators, belonging to trunnion mounted type. Quick Detail Type Ball Valve Size 20" Pressure ANSI 600 Construction Trunnion Type, One-Piece Body, Fully Welded, Metal to Metal Seat Connection Flanged Operation Bare Stem Body Material Forged Steel ASTM A105 Design Standard API 6D Pressure & Temp ASME B16.34 Face to Face Dimension ASME B16.10 End Connection ASME B16.5 Inspection API 598 Temperature Range -29℃~+200℃ Media Oil, Water, Gas Dimension CLASS 600 DN mm 50 65 80 100 150 200 250 300 350 400 450 500 NPS in 2 2.5 3 4 6 8 10 12 14 16 18 20 L (RF) mm 292 330 356 432 559 660 787 838 889 991 1092 1194 in 11.5 13 14 17 22 26 31 33 35 39 43 47 L1 (BW) mm 292 330 358 432 22 660 787 838 889 991 1092 1194 in 11.5 13 14 17 559 26 31 33 35 39 43 47 L2 (RTJ) mm 295 333 359 435 562 664 791 841 892 994 1095 1200 in 11.63 13.13 14.13 17.13 22.13 26.13 31.13 33.13 35 39.5 43.1 47.3 H mm 153 165 195 213 272 342 495 580 630 725 800 850 in 6.02 6.5 7.68 8.39 10.7 13.5 19.5 22.85 24.8 28.5 31.5 33.5 Do(W) mm 600 850 1250 1300 1500 *350 *350 *600 *600 *800 *800 *800 in 23.62 33.46 49.25 51.22 59 13.8 13.8 23.6 23.6 31.5 31.5 31.5 RF(Kg) 38 56 66 122 217 350 660 820 830 1160 1420 1650 BW(Kg) 31 51 58 117 200 327 605 790 800 1030 1305 1505 *Worm Gear or Electric actuator operated Related Knowledge When to use metal seated ball valve? The seat of a metal seated ball valve is often stellite, stainless steel, or tungsten carbide instead of soft seat material like ptfe, peek, nylon, teflon, and devlon. These metal to metal seat ball valves are especially applicable for: -Media with high temperature -Media with solid particulate for high abrasion -Media with severe condition, like high erosion and corrosion -Media with high viscosity like heavy oil Our Main Product Range Dervos main products include ball valves, butterfly valves, check valves, gate valves, globe valves, and plug valves in different materials, sizes, standards and types as per clients’ requests.
DN80 PN10 Air Release valve is made according to CJ/T217-2005 standard. The valve body is made of QT450. Its connection mode is EN1092-1.
The 8 inch lubricated plug valve features in inverted and pressure balanced type structure. The flanged metal seated plug valve is suited for natural gas application. Quick Detail Type Plug Valve Size 8'' Design Pressure 300LB Construction Lubricated Type, Inverted Type, Pressure Balanced Type, Metal Seated Connection Type Flanged Connection Operation Gear Operated Design Code API 599 Face to Face ASME B16.10 End Connection ASME B16.5 Pressure & Temp ASME B16.34 Test & Inspection API 598 Body Material WCC Temperature Range -29℃~+425℃ Application Water, Oil, Gas Dimension Class Size 1 1/2 2 2 1/2 3 4 6 8 10 12 300 B 191 216 241 283 305 403 419 457 502 C 156 165 191 210 254 318 381 445 521 D 20.6 22.2 25.4 28.3 31.8 36.5 41.3 47.6 50.8 E 169 178 219 235 362 F 106 118 143 165 187 248 300 392 O 73 92.1 105 127 157 216 270 324 381 Weight(RF) 16 21 38 60 101 192 281 508 Related Knowledge What is a plug valve? Plug valve is a quater-turn valve whose plug rotates around the centerline of valve body to realize on-off function. The plug valve is used for cutting off, distributing and changing the flow directoin. Currently, plug valves are mainly applicable for small size, normal temperature, and low pressure conditions. The advantages of plug valve are shown below: -Quick opening and closing the valve -Small fluid resistance -Reliable leak-tight service -Available inline maintenance
DN50 PN40 ball valve is made according to EN 17292 standard. The valve body is made of A182 F304. It has the structural characteristics of floating ball, full bore, anti-fire, anti-static, and anti-flying valve stem. Its connection mode is EN1092-1 B. And it has lever operation mode.
The 4 inch 150LB ball valve is a 3-piece one with reduced port, A105 body, F6A stem, ball and seat. The The valve is made as per API6D and is tested under API 598.
2" 600LB gate valve is made according to API 600 standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of rising stem, bracket, full bore and elastic wedge. Its connection mode is RTJ. And it has hand wheel operation mode.
With outside screw and yoke, handwheel operation, NPT, the forged steel globe valve is made of A105 and designed as per BS5352.
1" 2500LB check valve is made according to ASME B16.34 standard. The valve body is made of F316L. It has the structural characteristics of lifting type, pressure self-sealing, conventional diameter. Its connection mode is FNPT.
The stainless steel non return valve features in non slam type disc, INCONEL X750 spring, WCB valve body. This valve owns an excellent dynamic performance and minimizes vibrations and noise.
In 2017, DERVOS contributed to an innovative environmental initiative led by ECOFUEL, an emerging canadian player in clean technology. This groundbreaking project aimed to produce sustainable diesel from solid waste, setting a precedent in green energy solutions. DERVOS is proud to have provided 136 sets of premium valves to support this pioneering effort.
DN250 PN10 check valve body is made of A216 WCB+STL. It has the structural characteristics of heavy hammer on both sides and flange type. Its connection mode is RF.
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