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 When the valve is fully open, the gate is completely withdrawn from the flow path, allowing the fluid to pass through with minimal obstruction.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 ...
10’’ 300LB gate valve is made according to API 600 standard. The valve body is made of ASTM A217 C5 + STL. It has the structural characteristics of rising stem and bolt cover. The gate valve connected by flange has the operation mode of hand wheel.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
ASTM A217 C5 + STLMethod of Operation:
Handwheel OperationProduct Description
|
Type |
Gate Valve |
|
Size |
10’’ |
|
Pressure |
300LB |
|
Connection |
RF |
|
Operation |
Handwheel Operation |
|
Body Material |
ASTM A217 C5 + STL |
|
Design Norm |
API 600 |
|
Face to face dimension |
ASME B16.10 |
|
Flange dimension |
ASME B16.5 |
|
Test & Inspection Code |
API 598 |
|
Temperature |
-29 ~ 650°C |
|
Applicable Medium |
W.O.G.etc |
Features
1. Reasonable design, reliable sealing, smooth channel and small flow resistance coefficient;
2. High temperature and high pressure resistance, many optional materials, wide application range.
Technical Drawing
Dimension Checking
Witnessing Tests
Nameplate & Packing
Inspection report
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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.
6" 150LB gate valve is made according to API 600 standard. The valve body is made of ASTM A217 WC6. It has the structural characteristics of bolt cover, elastic gate, rising stem, OS&Y, full bore, body valve seat. Its connection mode is RF (125~250AARH）. And it has hand wheel operation mode.
2" 600LB Alloy Steel Gate Valve is made according to API 600 standard. The valve body is made of ASTM A217 WC6. It has the structural characteristics of Body cover bolt. Its connection mode is BW SCH 80. And it has Non lifting handwheel operation mode.
3" 300LB Alloy Steel Globe Valve is made according to API623 standard. The valve body is made of A217 WC6. It has the structural characteristics of through way type and structural length of 317.5mm. Its connection mode is RF. And it has hand wheel operation mode.
3/4”800LB C95500 Gate Valve is made according to API602 standard. The valve body is made of C95500. Its connection mode is SW. And it has Hand Wheel operation mode. Product Parameters Type Gate Valve Size 3/4” Pressure 800LB Connection SW Operation Hand wheel Body Material C95500 Design Norm API 602 End Dimension ASME/ANSI B1.20.1 Materials conform ASME/ANSI Test & Inspection Code API598 Applicable Medium Water, Oil and Gas Features 1.Manufactured from C95500 nickel aluminum bronze, delivering excellent corrosion resistance and strength in seawater and marine environments. 2.API 602 compliant gate valve with SW ends ensures compact installation and reliable shutoff in 800LB pressure applications. Technical Drawing Dimension Checking Pressure Testing Inspection Report
The Class 300 flanged ball valve has cast steel WCB body, stainless steel ball, stem, seat ring along with Devlon seat insert. We also supply more types of trunnion mounted ball valve, accept customized. Design Feature 1.Firesafe design as per API 607 2.With sealant injection for self lubricating 3.With antistatic design 4.With anti-blowout stem 5.With vent and drain port 6.Full bore design 7.Three-piece type and trunnion ball 8.Gear operated for easy operation Quick Detail Type Ball Valve Size 24" Pressure ANSI 300 Construction Trunnion Type Ball, 3-Piece Body, Side Entry, Full Bore Connection Flange Connection Operation Gearbox Operation Body Material ASTM A216 WCB Design Code API 6D Pressure & Temp Code ASME B16.34 Face to Face ASME B16.10 End Connection ASME B16.5 Test & Inspection Code API 598, API 6D Fire Safe API 607 Temperature Range -29℃~+200℃ Medium WOG Origin China Dimension CLASS 300 DN mm 50 65 80 100 150 200 250 300 350 400 450 500 600 700 NPS in 2 2.5 3 4 6 8 10 12 14 16 18 20 24 28 L (RF) mm 216 241 283 305 403 502 568 648 762 838 914 991 1143 1346 in 8.5 9.5 11.13 12 15.88 19.75 22.38 25.5 30 33 36 39 45 53 L1 (BW) mm 216 241 283 305 457 521 559 635 762 838 914 991 1143 1346 in 8.5 9.5 11.13 12 18 20.5 22 25 30 33 36 39 45 53 L2 (RTJ) mm 232 257 298 321 419 518 584 664 778 854 930 1010 1165 1372 in 9.13 10.13 11.75 12.63 16.5 20.38 23 26.13 30.63 33.63 36.63 39.75 45.89 54 H mm 153 165 195 213 272 342 495 580 625 720 790 840 1050 1150 in 6.02 6.5 7.68 8.39 10.7 13.5 19.5 22.85 24.6 28.35 31 33.1 41.34 45.3 Do(W) mm 400 400 600 850 1100 1500 *350 *350 *600 *600 *800 *800 *800 *800 in 15.74 15.74 23.62 33.46 43.3 59 13.8 13.8 23.6 23.6 31.5 31.5 31.5 31.5 RF(Kg) 18 27 47 80 118 200 365 530 740 1030 1320 1540 2600 3900 BW(Kg) 14 2 38 65 105 185 342 503 713 1000 1285 1498 2540 3825 *Worm Gear or Electric Actuator Operated Dervos Quality Checking System In Dervos, we control quality throughout the whole manufacturing process. Casting inspection: Though casting inspection, we can find out the problem of raw material, such as shoddy casting, unqualified wall thickness, chemical composition and so on, which ensure that you will not be cheated. Machining Inspection: On the one hand, we could ensure machining accuracy through this process. On the other hand, we can find out machining mistake as early as possible, to win more time for repairing and remaking Final Inspection: Final inspection activities include document and QC record review, visual examination, dimension check, pressure test, painting and packing check. You don’t need to come and inspect in person and all the documents could be provided as proof.
1" 800LB gate valve is made according to API 602 standard. The valve body is made of A182-F5. It has the structural characteristics of rigid gate, welded bonnet and extended valve body 100mm. Its connection mode is BW*NPT. And it has hand wheel operation mode.
DN300 PN16 Cast Steel Trunnion Mounted Ball Valve is made according to ISO17292 standard. The valve body is made of A351 CF8M. It has the structural characteristics of Two-Piece, Trunnion Mounted Ball, Full Bore, Fire-safe and Anti-static, Blow-out Proof Stem, Copper-Free Construction, Leakage Rate to EN12266 Rate A (Zero Leakage). Its connection mode is RF. And it has Pneumatically operation mode.
3/4" 150LB gate valve is made according to API 602 standard. The valve body is made of ASTM A182 F316L. It has the structural characteristics of bolt cover, rising stem and rigid wedge. Its connection mode is RF integral flange. And it has hand wheel operation mode.
Quick Detail Type Globe Valve Nominal Size NPS 2 NominalPressure Class 300 Construction BB, Rising Stem, Integral Seat Connection Type Flange Operation Type Handwheel Design Code BS1873 Face to Face ASME B16.10 Flange End ASME B16.5 Test & Inspection API 598 Body Material WCB+STL Trim Material F316+STL Temperature Range -29℃~425℃ Medium Water, Oil and Gas Origin China Design Feature 1. Straight pattern body structure 2. OS&Y, Rising Stem 3. Bolted Bonnet 4. Available with bevel gear operation 5. Plug type disc 6. Little abrasion on sealing face during valve operation 7. Smaller installation space required Technical Drawing Dimension Check Witnessing Tests Packing 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. Certificates Dervos could provide reports upon clients’requests, such as ISO 9001, PED CE, EAC, API 607, API 6D, API 6A and etc.
DN50 PN40 Y Type Strainer is made according to BS EN 12516 standard. The valve body is made of EN 10213 1.0619. It has the structural characteristics of Y-shaped, mesh size: 0.25 mm, without drain plug. Its connection mode is RF.
The dual disc wafer check valve is designed as per API 594 and tested per API 598. The bronze non return valve is applicable for sea water. Quick Detail Type Check Valve Size 6'' DesignPressure Class 150 Construction Dual Plate Type, With Retainer Connection Wafer Type Design & Manufacture API 594 End to End ASME B16.10 Connection ASME B16.5 Pressure & Temp ASME B16.34 Test & Inspection API 598 Body Material Aluminum Bronze C95800 Trim Material Aluminum Bronze C95800 Media W.O.G. Dervos Inspection after Valve Assembly Valve quality is one of perspectives we care about most. In Dervos, quality control starts from raw material, machining, assembly to pre-shipment inspection. After assembly, the quality checking team will do visual checking, dimension checking, hydraulic testing and air testing. Every order must pass the test per inspection standards. Otherwise our quality checking team will not release the shipment. Inspection Reports Documents can be used to prove how we control valve quality. Along with every order, Dervos will provide clients with an inspection report & a 3.1 mill test report for free. In Dervos inspection report, you will see the actual results of dimension checking and pressure testing along with painting and packing picture. All these info are shown through data and clear pictures. In 3.1 mill test report, we will show you the chemical composition, mechanical property and heat number for valve body, bonnet, stem, disc and so on.
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