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!
2" 150LB plug valve is made according to API 599 standard. The valve body is made of A216 WCB. It has the structural characteristics of four way and bolt cover. 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:
API 599Product Description
|
Type |
Plug Valve |
|
Size |
2" |
|
Pressure |
150LB |
|
Connection |
RF |
|
Operation |
Turbine Operation |
|
Body Material |
A216 WCB |
|
Design Norm |
API 599 |
|
End Flange Dimensions |
ASME B16.5 |
|
Face to Face |
Factory standards |
|
Test & Inspection Code |
API 598 |
|
Pressure-Temp |
ASME B16.34 |
|
Temperature |
≤ 120°C |
|
Applicable Medium |
Water, Oil and Gas |
Features
1. Simple structure, small size, light weight, easy maintenance;
2. The sealing performance is not limited by the installation direction, and the flow direction of the medium can be arbitrary.
3. It is suitable for frequent operation and can be opened and closed quickly and easily.
Technical Drawing
Dimension Checking
Pressure Testing
Painting
Nameplate & Packing
Inspection report
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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.
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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.
DN50 PN16 Cast Steel gate valve is made according to BS EN 1984 standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of bolt cover, exposed pole. Its connection mode is EN1092-1 B. And it has Hand Wheel operation mode.
DN100 PN16 check valve is made according to EN12516-1 standard. The valve body is made of ASTM A216 WCB+STL. It has the structural characteristics of lifting type with spring. Its connection mode is EN1092-1 B.
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.
4 Inch 150LB Cast Steel Swing Check Valve is made according to API 6D standard. The valve body is made of ASTM A351 CF8M. It has the structural characteristics of Swing Type, External Pin. Its connection mode is RF.
3/4” 800LB Floating Ball Valve is made according to ASME B16.34 standard. The valve body is made of A182 F316L. It has the structural characteristics of Full Bore, Floating Ball, Middle Welded Body, Fire-safe and Anti-static, Blow-out Proof Stem. Its connection mode is Lever OP..
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.
DN25 PN16 Forged Floating Ball Valve is made according to ISO17292 standard. The valve body is made of ASTM A105. It has the structural characteristics of Design Features: Floating Ball, Full Port, Fire-safe & Anti-static Design, Blow-out Proof Stem. Its connection mode is EN1092-1 B1. And it has hand wheel operation mode.
API 6D ball valve is designed with an extended stem for special use, like underground ball valve or low temperature application. The length of the extended stem can be customized as per client's request. Quick Detail Type Ball Valve Size 2 Inch Pressure Class 600 Construction Split Body, Side Entry, Floating Type, Firesafe Design, Antistatic System, Anti-Blowout Stem, Extended Bonnet Connection RF Flange Operation Mode Lever Body Material A105N Trim Material SS304 Ball and Stem, RPTFE Seat 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 QC Process in Dervos Casting inspection： We can find out the raw material’s problem, such as shoddy casting, unqualified wall thickness, chemical composition and so on, which ensure that you will not be cheated. Machining Inspection: -Ensure machining accuracy -Find out machining mistake as early as possible, to win more time for repairing, remaking Final Inspection: -Final inspection activities include document and QC record review, visual examination, dimension check, pressure test, painting and packing check -Save time and cost: you don’t need to come and inspect in person and all the documents could be provided as proof. Inspection report will be provided free of charge including: -EN 10204 3.1 Mill Test Certificate -Inspection Report, showing the whole inspection process
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