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 When the valve is fully open, the gate is completely withdrawn from the flow path, allowing the fluid to pass through with minimal obstruction.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 ...
The 1 inch sleeved type plug valve is made of A216 WCB as per API 599. Thanks to its PTFE seat, the valve has excellent sealing and anti-corrosion performance. The valve is capable in working condition lower than 180 degree.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
WCBMethod of Operation:
Lever/Wrench
Quick Details
|
Type |
Plug Valve |
|
Size |
1 Inch |
|
DesignPressure |
Class 600 |
|
Construction |
Sleeve Type Plug Valve |
|
Connection Type |
Flange Connection |
|
Operation |
Lever/Wrench |
|
Design Code |
API599 |
|
Face to Face |
ASME B16.10 |
|
End Connection |
ASME B16.5 |
|
Pressure & Temp |
ASME B16.34 |
|
Test & Inspection |
API 598 |
|
Body Material |
A216 WCB |
|
Temperature Range |
<180℃ |
|
Application |
W.O.G |
General description
The simplest form of a plug valve is the petcock. The body of a plug valve is machined to receive the tapered or cylindrical plug. The disk is a solid plug with a bored passage at a right angle to the longitudinal axis of the plug. In the open position, the passage in the plug lines up with the inlet and outlet ports of the valve.
When the cap is rotated 90 ° from the open position, the solid part of the cap blocks the ports and stops the flow of fluid. The plug valves are available in a lubricated or non-lubricated design and with a variety of styles of port openings through the plug, as well as a number of plug designs.
Technical Drawing
FAQ
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Our purchasing team follows up very closely with each order to make sure on-time delivery for most of orders. In 2018, more than 90% orders were delivered on time, and we are dedicated to doing better.
2. What’s the normal delivery lead time?
For normal material, usually the delivery time is about 35~40 days, and for forged material, the delivery can even be shortened to 20~25 days. We believe the short lead time can make our offer more competitive and help you secure more orders.
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The 6 inch sleeved plug valve features in non lubricated design and soft seat. The full port plug valve is made of carbon steel body and PTFE seat as per API 6D, with Class 150 flange connection. Quick Detail Type Plug Valve Size 6'' Design Pressure 150LB Construction Self-Lubricated Type, Sleeved Type, Soft Seat Connection Type RF Flange Operation Gearbox Operation 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 A216 WCB Temperature Range -29℃~+425℃ Application Water, Oil, Gas Material & Dimension No Part Name Carbon steel to ASTM Stainless steel to ASTM WCB LCB CF8 CF8M CF3 CF3M 1 Body A216 WCB A350 LCB A351 CF8 A351 CF8M A351 CF3 A351 CF3M 2 Bonnet A216 WCB A350 LCB A351 CF8 A351 CF8M A351 CF3 A351 CF3M 3 Plug A105 A182 F304 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 4 Stem A182 F6 A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 5 Seat Ring PTFE 6 Gasket PTFE or Stainless Steel and Graphite 7 Stem Seat PTFE PTFE PTFE PTFE PTFE PTFE 8 Small spring 17-17PH 9 Small ball A182 F304 or A182 F316 10 Gland A182 F6 A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 11 Gland Flange A216 WCB A350 LCB A351 CF8 A351 CF8M A351 CF3 A351 CF3M 12 Stem packing PTFE or Graphite 13 Bonnet bolt A193 B7 or A320 L7 or A320 B8 or A193 B8M 14 Bonnet nut A194 2H or A194 4 or A194 8 Class 150 DN mm 15 20 25 40 50 65 80 100 150 200 250 300 NPS in 1/2 3/4 1 1 1/2 2 2 1/2 3 4 6 8 10 12 L(RF) mm 108 117 127 165 178 191 203 229 394 457 533 610 in 4.25 4.6 5 6.5 7 7.5 8 9 15.5 18 21 24 L1(BW) mm 140 152 165 190 216 241 283 305 457 521 559 635 in 5.5 6 6.5 7.48 8.5 9.5 11.13 12 18 20.5 22 25 L2(RTJ) mm 119 129.7 139.7 178 191 203 216 241 406 470 546 622 in 4.69 5.11 5.5 6.9 7.5 8 8.5 905 16 18.5 21.5 24.5 H mm 59 63 75 92 153 165 195 213 272 342 495 580 in 2.3 2.5 2.95 3.74 6.02 6.5 7.68 8.39 10.7 13.5 19.5 22.85 D(W) mm 130 130 160 230 400 400 600 850 1100 1500 350* 350* in 5.1 5.1 6.3 9 15.74 15.74 23.62 33.46 43.3 59 13.8 13.8 Weight (Kg) RF 2.3 3 4.5 7 15 20 25 40 97 160 240 390 BW 2.0 2.5 3.8 5.8 12 17 21 36 92.8 154 227 365
The PTFE sleeved plug valve is made of CF3 body and plug as per API 6D. The valve owns the feature of reduced port and good sealing performance. We call this type of valve as non lubricated plug valve or self lubricated plug valve. Quick Detail Type Plug Valve Size 2'' DesignPressure 300LB Construction Sleeved Type, Non Lubricated Type, Soft Seat ConnectionType Flange Operation Lever Operation Design Code API 599, API 6D Face to Face ASME B16.10 End Connection ASME B16.5 Pressure & Temp ASME B16.34 Test & Inspection API 598 Body Material CF3 Temperature Range -29℃~+120℃ Application Water, Oil, Gas Dimension Checking Hydrostatic Testing
This 1/2 Inch plug valve is made of A216 WCB, according to API598.With little required maintenance and trouble-free operation, a high integrity bubble-tight seal is provided both in-line and to atmosphere.
Non-Lubricated, Sleeved Plug Valves incorporate state-of-the-artPPL seat design. With little required maintenance and trouble-free operation, the 3 inch 150 LB valve will ensure a high integrity bubble-tight seal.
DN250 PN25 plug valve is made according to API599 standard. The valve body is made of A216 WCB. It has the structural characteristics of soft sealing plug valve. Its connection mode is RF. And it has turbine operation mode.
DN50 PN40 plug valve is made according to API 599 standard. The valve body is made of A216 WCB. It has the structural characteristics of ferrule type, reduced diameter. Its connection mode is RF. And it has lever operation mode.
10" 300LB gate valve is made according to API 600 standard. The valve body is made of ASTM A217 C5. It has the structural characteristics of bolt cover, elastic gate, rising stem, OS&Y, full bore and body valve seat. Its connection mode is RF (125~250AARH). And it has bevel gear operation mode.
The 12 inch 150 LB triple eccentric butterfly valve is designed per API 609 with flange end and gearbox operation. The valve is made of stainless steel CF8 with metal seat design. Quick Detail Type Butterfly valve Size 12 Inch Pressure 150LB Construction Triple Offset/Eccentric, Metal Seat Connection Type Flange Operation Gearbox Design Code API 609 Face to Face ANSI B16.10 End Connection ANSI B16.5 Test & Inspection API 598 Body Material CF8 Applicable Temp -196℃~+800℃ Application Water, Oil, Gas Materials Dimension
3" 150LB Swing Check Valve is made according to API6D standard. The valve body is made of WCB. It has the structural characteristics of Bolted Bonnet, Swing Type, Suitable for Horizontal and Vertical Installation. Its connection mode is RF. Product Parameters Type Swing Check Valve Size 3” Pressure 150LB Connection RF Body Material WCB Design Norm API 6D Face to face ASME B16.10 Flange dimension ASME B16.5 Test & Inspection Code API 598 Temperature -29 ~ 425°C Applicable Medium Water, Oil and Gas etc Features 1.Swing design allows unobstructed flow and prevents backflow in pipelines. 2.WCB body meets API6D standards, ensuring reliable performance under high pressure. Technical Drawing Dimension Checking Pressure Testing Painting Nameplate & Packing Inspection Report
The 8 inch Class 2500 gate valve is designed with pressure seal bonnet, butt weld connection, and gearbox operation. The 8 inch gate valve has carbon steel WCB body and trim 5. Quick Detail Type Gate Valve Size 8'' Design Pressure ANSI 2500 Construction Pressure Seal Bonnet, Flexible Wedge, Metal to Metal Seat ConnectionType Butt Weld (SW) OperationType Gearbox Operation Body Material A217 WC6 TrimMaterial Trim 5 Design Code API 600 Face to Face Dimension ASME B16.10 End Connection ASME B16.25 Pressure & Temp ASME B16.34 Medium Water, Oil and Gas Origin China Dimension & Material NPS DN Class 2 2 1/2 3 4 6 8 10 12 14 16 18 20 24 50 65 80 100 150 200 250 300 350 400 450 500 600 L(RF) 900LB 368 419 381 457 610 737 838 965 1029 1130 1500LB 368 419 470 546 705 832 991 1130 1257 1384 2500LB 451 508 578 673 917 1022 1270 L1(BW) 900LB 216 254 305 355 508 660 787 914 991 1092 1346 1473 1600 1500LB 216 254 305 406 559 711 864 991 1067 1194 1697 2500LB 279 330 368 457 610 762 914 1041 1118 1245 L2(RTJ) 900LB 371 422 384 460 613 740 841 968 1038 1140 1500LB 371 422 473 549 711 841 1000 1146 1276 1407 2500LB 454 514 584 683 927 1038 1292 H(Opne) 900LB 554 637 680 796 1084 1372 1494 1550 1960 2210 1500LB 554 637 767 875 1094 1372 1655 1834 2150 2260 2460 2721 2940 2500LB 610 654 753 850 1254 1374 1685 1894 2226 2382 2585 W 900LB 300 350 350 400 560 460* 610* 610* 610* 760* 1500LB 300 450 450 560 305* 460* 610* 610* 760* 760* 2500LB 500 500 600 600 460* 460* 610* Weight (RF) 900LB 50 84 92 154 341 622 950 1295 1720 2380 1500LB 60 91 128 182 394 795 1370 2120 2800 3870 2500LB 121 175 195 229 720 1295 2250 Weight (BW) 900LB 39 64 82 120 266 524 760 1090 1450 2018 1500LB 46 71 85 130 292 578 974 1615 2010 2815 3315 4150 5219 2500LB 88 135 144 158 500 892 1550 1978 2580 3780 5988 *Manual gear operator is recommended No. Part WCB WC6 WC9 C5 CF8 CF8M 1 Body A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M 2 Seat A182 F6a A182 F22 A182 F22 A182 F5 A182 F304 A182 F316 3 Wedge A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M 4 Stem A182 F6a SAEHNV3 A182 F304 A182 F316 5 Stuffing Box A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M 6 Seal Ring ANSI 316L Flexible Graphite+316 7 Split Ring Steel F6 F6 F6 A182 F304 F316 8 Back Ring Steel Steel Steel Steel SS SS 9 Bolt A193 B7 A193 B7 A193 B7 A193 B7 A193 B8 A193 B8 10 Nut A194 2H A194 2H A194 2H A194 2H A194 Gr.8 A194 Gr.8 11 Yoke A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M 12 Bolt A193 B7 A193 B7 A193 B7 A193 B7 A193 B8 A193 B8 13 Nut A194 2H A194 2H A194 2H A194 2H A194 Gr.8 A194 Gr.8 14 Packing Plate ANSI 410 ANSI 410 ANSI 410 ANSI 410 ANSI 304 ANSI 316 15 Packing Flexible Graphite(Braided and Ring) or PTFE 16 Split Pin Steel Steel Steel Steel Steel Steel 17 Eyebolt A193 B7 A193 B7 A193 B7 A193 B7 A193 B8 A193 B8 18 Gland A182 F6 A182 F6 A182 F6 A182 F6 A182 F304 A182 F316 19 Gland Flange A105 A105 A105 A105 A182 F304 A182 F316 20 Nut A194 2H A194 2H A194 2H A194 2H A194 Gr.8 A194 Gr.8 21 Stud A193 B7 A193 B7 A193 B7 A193 B7 A193 B7 A193 B7 22 Stem Nut Ni-resist A439-D2 23 Gear Box Purchased 24 Protector Steel 25 Nameplate ANSI 304 26 Rivet ANSI 304
3/4" 800LB globe valve is made according to API 602 standard. The valve body is made of A105N+ STL. It has the structural characteristics of plug, disc swivel plug, body seat and OS&Y. Its connection mode is SW+FNPT. And it has hand wheel operation mode.
Made of A182-F316L, 1/2’’ 150LB ball valve is made according to API 608 standard. It has the structural characteristics of floating ball and two-piece ball valve.Its connection mode is RF and there is a handle operation mode.
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