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 When the valve is fully open, the gate is completely withdrawn from the flow path, allowing the fluid to pass through with minimal obstruction.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 ...
Product Origin:
ChinaColor:
CustomizationShipping Port:
Ningbo/Shanghai,ChinaLead Time:
30~55 days Ex Works After Order ConfirmationMaterial:
ASTM A105Method of Operation:
HandwheelThe bellows seal globe valve adopts the bellows seal design, which completely eliminates the shortcomings of the normal valve stem packing seal aging and easy to leak, not only improves the energy efficiency, increases the safety of the production equipment, reduces the maintenance cost and frequent maintenance. It also provides a clean and safe working environment.Its simple structure and the low price makes it almost no "competitors".
Quick Detail
|
Type |
Globe Valve |
|
Norminal Size |
1.5 Inch |
|
NorminalPressure |
150LB |
|
Construction |
Bolted Bonnet, Outside Screw & Yoke, Rising Stem, Bellow Seal |
|
ConnectionType |
RF Flange |
|
Operation |
Handwheel |
|
Design Code |
ASME B16.34, API 602 |
|
Face to Face |
ASME B16.10 |
|
Flange End |
ASME B16.5 |
|
Test & Inspection |
API 598 |
|
Body Material |
ASTM A105 |
|
ApplicableTemp |
-29℃~+425℃ |
|
Application |
Water, Oil, Gas |
Structure Feature
1. Double seal design (corrugated pipe + packing). If the bellows fails, the stem packing will also be avoided;
2. External leakage, and in line with international sealing standards;
3. No fluid loss, reduce energy loss, and improve plant equipment safety;
4. Long service life, reduce the number of maintenance, reduce operating costs;
5. Rugged bellows seal design, ensuring zero leakage of the valve stem, providing maintenance-free conditions.
Technical Drawing
Dimension
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.
If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.
The 1.5 inch 800LB bellow seal globe valve is designed with outside screw and yoke, handwheel operation, sw end. The reduced port globe valve is has forged steel A105N body. Design Feature 1.Outside screw and yoke 2.Rising stem 3.Bolted bonnet design 4.Bellow seal packing for reliable stem sealing 5.Reduced bore design 6.Handwheel Operated Quick Detail Type Globe Valve Size 1.5'' Design Pressure Class 800 Structure BB, OS&Y, Reduced Port, Bellow Seal Packing Connection Type Socket Weld Operation Handwheel Design Code API 602 End to End ASME B16.10 Connection End ASME B16.11 Pressure & Temperature ASME B16.34 Test & Inspection Standard API 598 Body Material Forged Steel ASTM A105 Trim Material Trim 8 Applicable Temperature -29℃~+425℃ Application W.O.G Origin China Related Knowledge What is a bellw seal valve? For bellow seal globe valves, the lower end bellows is welded on the valve stem to prevent the process fluid from eroding the valve stem. The other end is placed between the valve body and the valve cover to form a static seal. The double seal design ensure that if bellow seal pakcing fails, the stem packing will also function. The bellow seal globe valves are applicable for media like steam, flammable, explosive, heat transfer oil, high purity, and toxic media etc. Special Tests Besides general tests we will do (hydraulic and air test), we could also do tensile strength test, metallographic test, fugitive emission test, and NDE test (UT,RT,PT,MT) upon customers’ specific requests.
Dervos bellow seal globe valve is designed as per EN13709 with face to face dimesnsion per EN558. The special designed bellow seal make sure zero leakage from stem. Quick Detail Type Globe Valve Norminal Size DN 65 NorminalPressure PN 40 Construction Bolted Bonnet, Rising Stem, Bellow Sealed ConnectionType RF Flange Operation Handwheel Design Code EN13709 Face to Face EN 558 Connection EN1092 Test & Inspection EN12266 Body Material Carbon Steel 1.0619 Bellow Material SS304, SS316, SS316L and etc ApplicableTemp -29℃~+420℃ Application Water, Oil, Gas Structure Feature 1. Standard design of double-wall bellow seal 2. Heat-dissipating bonnet design; 3. With lubricant storage device; 4, With design of circlip to fix stem nut; 5. Reasonable product structure, reliable sealing performance and good appearance; 6. The sealing surface is welded with Co-based hard alloy, which has good wear resistance, corrosion resistance, anti-friction performance and long service life; 7. Stem has nitriding treatment with good corrosion resistance and anti-friction performance; 8. With position indicator for stem movement;
DN200 PN16 Bellow Seal Globe valve is made according to BS EN 13709 standard. The valve body is made of EN 10213 1.4408. It has the structural characteristics of body cover bolt, rising pole bracket, angle type, corrugated pipe seal and structural length of 255mm. Its connection mode is RF. And it has hand wheel operation mode.
1" 300LB Forged Steel Bellows Globe Valve is made according to API602 standard. The valve body is made of A350-LF2+316. It has the structural characteristics of Welded Bonnet, Rising Stem (OS&Y), Bellows Type. Its connection mode is RF. And it has Handle Wheel operation mode. Product Parameters Type Forged Steel Bellows Globe Valve Size 1” Pressure 300LB Connection RF Operation Hand wheel Body Material A350-LF2+316 Design Norm API602, ASME/B16. 34 Face to Face ASME/B16.10 Flange dimension conform ASME B16.5 Test & Inspection Code API598 Temperature -46 ~ 345°C Applicable Medium Water, Oil and Gas Features 1. LF2 forged steel body offers excellent low-temperature toughness and structural reliability for 300LB service. 2.Bellows-sealed globe valve design compliant with API 602 eliminates stem leakage and ensures safe, precise flow control. Technical Drawing Dimension Checking Pressure Testing Nameplate & Packing
1/2" PN100 needle valve is made according to ASME B16.34 standard. The valve body is made of A105. It has the structural characteristics of straight-through. Its connection mode is Male/Female NPT. And it has lever operation mode.
1/2" 800LB ball valve is made according to ASME B16.34 standard. The valve body is made of A105N. It has the structural characteristics of floating ball, full bore, anti-fire, anti-static. Its connection mode is NPT. And it has lever operation mode.
3” 600LB Dual Plate Wafer Type Check Valve is made according to API594 standard. The valve body is made of N08825. It has the structural characteristics of Dual-plate, wafer type, suitable for both horizontal and vertical installation. Its connection mode is RTJ.
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
DN80 PN160 Forged Floating Ball Valve is made according to EN 12266 standard. The valve body is made of ASTM A105N. Its connection mode is LG. And it has Hand Wheel operation mode. Product Parameters Type Forged Floating Ball Valve Size DN80 Pressure PN160 Connection LG Operation Hand Wheel Body Material ASTM A105N Design Norm ISO 14313 Face to Face MFR’S End connection LG Test & Inspection Code EN 12266 Temperature -29 ~ 120°C Applicable Medium Water, Oil and Gas Features 1.Forged A105N carbon steel body ensures excellent mechanical strength and reliable performance in PN160 high-pressure applications. 2.Floating ball valve design tested to EN 12266 leakage grade LG provides tight shutoff and dependable sealing integrity. Technical Drawing Dimension Checking Pressure Testing
6" 150LB y type strainer is made according to ASME B16.34 standard. The valve body is made of ASTM A351 CF8. It has the structural characteristics of Y-shaped, body cover bolted connection. Its connection mode is RF.
Globe valve with a non-return design, preventing reverse flow when in the open position, also suitable for isolation duty. Manually operated, supplied with a handwheel.
DN40 PN40 floating ball valve is made according to EN 13709 standard. The valve body is made of A182 F316L. It has the structural characteristics of floating ball. Its connection mode is RF. And it has lever operation mode.
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