In a wedge gate valve, the gate sealing surfaces are wedge-shaped, forming a specific angle relative to the gate centerline. The gate is driven downward by the valve stem to achieve closure. As the stem thrust increases, the normal force acting on the wedge-shaped sealing surfaces also increases, creating a forced sealing effect. This design significantly improves sealing performance under low-pressure conditions. During opening, the gate sealing surfaces disengage from the seat immediately, which helps reduce wear on the sealing faces and extends the service life of the valve. Applicable Standards for Wedge Gate Valves Wedge gate valves are commonly manufactured in accordance with the following standards: ● GB/T 12234-2019 – Steel gate valves with bolted bonnet for petroleum and natural gas industries ● GB/T 12232-2005 – General-purpose flanged cast iron gate valves ● API Standard 600 (2015) – Steel gate valves for petroleum and natural gas industries Types of Wedge Gate Valve Gates Wedge gate valves are typically available in three gate configurations:Solid wedge gate, Flexible wedge gate, Double wedge gate. The flexible wedge gate and double wedge gate rely on controlled deformation of the sealing surfaces to achieve improved contact with the valve seat. This design enhances sealing reliability and effectively prevents gate binding or jamming caused by temperature variations, ensuring smooth operation even under fluctuating thermal conditions. Parallel Slide Gate Valve Design and Sealing Principle In a parallel slide gate valve, the sealing surfaces at both the inlet and outlet ends of the gate are parallel to the gate centerline. For single-gate configurations, sealing is primarily achieved by the medium pushing a floating gate or floating seat into position. In double-gate configurations, sealing can be accomplished through springs or an expansion mechanism between the gates. Throughout the opening and closing process, the gate and seat sealing surfaces remain in constant contact, ensuring reliable sealing. Applicable Standards for Parallel Slide Gate Valves Common standards for parallel slide gate valves include: ● GB/T 23300-2009 – Parallel slide gate valves ● JB/T 5298-2016 – Steel parallel slide gate valves for pipelines ● API 6D – Pipeline valves for petroleum and natural gas industries Types and Features of Parallel Slide Gate Valves Parallel slide gate valves are available in single-gate and double-gate configurations. ● Gates may include flow-through holes or be solid. Gates with flow-through holes match the seat inner diameter, facilitating cleaning and drainage of the pipeline. ● Sealing can be configured at the inlet end, outlet end, or at both ends, depending on application requirements. This design ensures flexibility in sealing arrangements while maintaining reliable oper...
Damage to valve sealing surfaces is typically the result of multiple contributing factors, including material selection, operating conditions, operating practices, and maintenance. The following is a categorized summary of the most common causes: 1. Mechanical Damage ● Wear: Solid particles in the medium (such as sand or welding slag) erode the sealing surface, resulting in scratches or grooves. ● Abrasive scuffing: Frictional wear caused by relative movement of the sealing surfaces during valve opening and closing, particularly in metal-to-metal sealing pairs. ● Impact damage: Deformation of the sealing surface caused by high-velocity fluid impingement or rapid valve opening and closing, leading to impact loading. 2. Chemical Corrosion ● Media corrosion: Acidic, alkaline, or oxidizing media directly attack the sealing surface material, such as metal corrosion caused by H₂S or chloride ions. ● Electrochemical corrosion: When sealing pairs made of dissimilar metals are exposed to an electrolyte, galvanic corrosion may occur due to electrochemical cell formation. ● Erosion–corrosion: The combined effect of corrosive media and high-velocity flow accelerates material loss on the sealing surface. 3. Thermal Damage ●Thermal fatigue:Frequent temperature fluctuations cause repeated thermal expansion and contraction of the sealing surface, leading to cracking or deformation. ●High-temperature oxidation:At elevated temperatures, the sealing surface may undergo oxidation, hardening, or burn-off, as commonly observed in steam valve applications. ●Thermal shock:Sudden exposure to high- or low-temperature media can cause cracking of the sealing surface, such as during rapid condensation or cold media ingress. 4. Improper Installation and Operation ●Installation misalignment: Incorrect valve installation or excessive piping stress can result in uneven loading on the sealing surfaces. ●Over-tightening: Excessive preload applied to the valve stem or bolting may crush or deform the sealing surface, particularly in soft-seated valves or soft sealing gaskets. ●Rough operation: Rapid opening and closing or excessive operating force can cause impact damage to the sealing surfaces. 5. Material Defects ●Improper material selection: The sealing surface material lacks sufficient resistance to process media, high temperature, or wear, such as the use of carbon steel in acidic service. ●Manufacturing defects: Defects in the hardfacing or overlay layer, including porosity, slag inclusions, or improper heat treatment, reduce wear resistance and overall sealing performance. 6. Abnormal Operating Conditions ●Cavitation / flashing: Pressure fluctuations in the fluid generate vapor bubbles that collapse and impact the sealing surface, a phenomenon commonly observed in valves installed downstream of pumps. ●Scaling / deposition: Impurities in the medium accumulate on the sealing surface, impairing tight shutoff, suc...
In 2025, Dervos organized its annual team trip, a five-day journey to Chongzuo, Weizhou Island, and Nanning in Guangxi Province. The trip aimed to provide relaxation and strengthen team communication, offering a well-paced and content-rich experience that combined natural landscapes with local cultural immersion. In Chongzuo, the team focused on nature sightseeing. Bamboo rafting tours allowed close observation of the local ecology and offered opportunities to see rare species such as the white-headed leaf monkey. The group also visited Detian Waterfall, experiencing its scale and flow firsthand. The overall itinerary was designed with a relaxed pace, providing ample time for rest and team bonding. Next, the team traveled to Weizhou Island. The volcanic landforms and coastal scenery added a unique visual dimension to the journey. Beyond sightseeing, participants engaged in local agricultural activities, including dragon fruit picking and banana harvesting, gaining insight into local lifestyles. The team also visited several beaches, fully appreciating the island environment. The final stop was Nanning. Team members explored the night market, sampled local specialties, and experienced the city’s daily life, bringing the Guangxi trip to a relaxed conclusion. This annual trip allowed the Dervos team to foster more natural communication and connection outside of work, recharging energy for the months ahead. Dervos remains committed to its guiding principle: I come, I see, I conquer!
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.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
A216 WCBMethod of Operation:
Turbine OperationProduct Description
|
Type |
Plug Valve |
|
Size |
DN250 |
|
Pressure |
PN25 |
|
Connection |
RF |
|
Operation |
Turbine Operation |
|
Body Material |
A216 WCB |
|
Design Norm |
API 599 |
|
End Flange Dimensions |
EN1092-1 |
|
Face to Face |
EN558-1 |
|
Pressure Test |
API 598 |
|
Pressure-Temp |
ASME B16.34 |
|
Temperature |
≤ 120°C |
|
Applicable Medium |
Water, Oil and Gas |
Features
1. Low resistance, easy and fast opening and closing;
2. Simple structure, convenient operation, and low fluid resistance.
Technical Drawing
Dimension Checking
Pressure Testing
Painting
Nameplate & Packing
Inspection report
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 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.
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.
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.
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.
The top entry full port ball valve with drain, vent and sealant injection is designed as per API 6D. The high pressure ball valve has Class 900 raised face flange and gearbox. Quick Detail Type Ball Valve Size 16" Pressure ANSI 900 Construction 1 Piece Body, Top Entry, Bolted Bonnet Connection Flanged End Operation Mode Gearbox Body Material A216 WCB Design & Manufacture API 6D Pressure & Temp Code ASME B16.34 End to End ASME B16.10 End Connection ASME B16.5 Inspection API 6D, API 598 Temperature Range -29℃~+200℃ Medium Oil, Water, Gas Related Knowledge What is a top entry ball valve and its advantage? A top entry ball valve is the valve which we assemble from the top side. It has a one single piece body. The less thread connection on the valve body means less weight and leakage paths. Plus, we could have access to the ball part without removing it from the pipeline. The top entry ball valves are often used in the pipeline with less maintenance for internal parts. Inspection Reports For each order, Dervos will provide inspection reports to show you the whole inspection process and results. Plus, we will provide material report to let you know that the material we provide is as per standards.
The 3 way plug valve is made of WCB body and stainless steel trim as per API 599. The plug valve that could connect any two ports together is applicable for natural gas service, water, oil and so on. Quick Detail Type Plug Valve Size 4'' DesignPressure 150LB Construction Three Way Type Plug Valve ConnectionType Flange Connection Operation Lever/Wrench 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 TemperatureRange -29℃~+425℃ Application WOG Related Knowledge What are types of plug valves? Lubricated Plug Valve The plug gets lubricated by injecting sealant through injection fitting. The lubricant make sure the smooth movement and prevent the corrosion of plug. Usually, the seat of lubricated plug valve is metal, thus they can withstand higher temperature, available in larger size and higher pressure. Non-Lubricated Plug Valve A non-metallic sleeve or liner is installed in the body cavity of the plug valve. This sleeve reduce the fricion beween plug and body. Meanwhile it prevents the corrosion of plug. Due to non-metallice sleeve, the non-lubricated plug valve cannot be used in high temperature condition. Multiway Plug Valve The multiway plug valve is used for diverting flow in transfer lines. The multiway plug valves we often see are 3 way plug valve or 4 way plug valve. Dervos Packaging Based on sufficient experience, we have developed complete packing specifications and procedures to ensure clear and safe transportation so that you can receive good and sound products. And this is also an important factor that we earn good reputation from our customers.
DN15 PN40 steam trap valve is made according to GB/T22654-2008° standard. The valve body is made of A105. It has the structural characteristics of bimetal type and BK47-Y model. Its connection mode is RF.
DN40 PN40 Lift Check valve is made according to BS EN 13709 standard. The valve body is made of EN 10213 1.0619. It has the structural characteristics of Lift type with spring. Its connection mode is EN1092-1 B1.
DN25 800LB Forged Steel Floating Ball Valve is made according to ASME B16.34 standard. The valve body is made of F316L. The valve is equipped with B8M/8M bolts and nuts, prohibits the use of Viton, zinc, copper, and their alloys, features an O-ring-free design with a gland, and uses PTFE gaskets and packing for reliable sealing. Its connection mode is BW Sch 40.The valve is operated by Handle with Locking Device, SS Material.
3" 150LB Cast Stainless Steel Check Valve is made according to BS1868 standard. The valve body is made of CF3M+STL6. It has the structural characteristics of Ball Check, Swing Type. Its connection mode is RF ,S-10S, 125:250AARH. Product Parameters Type Cast Steel Check Valve Size 3” Pressure 150LB Connection RF Body Material CF3M+STL6 Design Norm BS1868 Face to Face ASME B16.10 Flange ASME B16.5 Test & Inspection Code API 598 Temperature -29 ~ 300°C Applicable Medium Water, Oil and Gas Features 1.Made from CF3M cast stainless steel, providing excellent corrosion resistance and durability for 150LB pressure systems. 2.Floating ball design with RF flange, compliant with BS1868, ensures reliable sealing and smooth operation. Technical Drawing Cast Steel Swing Check Valve Dimension Checking Pressure Testing Nameplate & Packing Inspection Report
Copyright © 2015-2026 DERVOS VALVE CO.,LTD.All Rights Reserved Blog / Sitemap / XML / Privacy Policy
