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!
Product Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai ChinaLead Time:
30~55 days Ex Works After Order ConfirmationMaterial:
Cast Steel Globe ValveMethod of Operation:
HandwheelDervos 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;
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.
The 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.
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.
3/4” 150LB Forged Steel Floating Ball Valve is made according to API608 standard. The valve body is made of A182 F304. It has the structural characteristics of Full Bore, Floating Ball, Fire-safe and Anti-static, Blow-out Proof Stem. Its connection mode is NPT. And it has hand wheel operation mode. Product Parameters Type Forged Steel Floating Ball Valve Size 3/4” Pressure 150LB Connection NPT Operation H.W. Body Material A182 F304 Design Norm API 608 Face to Face MFG Screwed End ASME B1.20.1 Test & Inspection Code API 598 Temperature -29 ~ 120°C Applicable Medium Water, Oil and Gas Features 1.High-temperature F304 stainless steel body ensures superior corrosion resistance and durable performance. 2.API 608 certified design guarantees reliable shut-off and long-term service in demanding industrial application. Technical Drawing Dimension Checking Pressure Testing Nameplate & Packing Inspection Report
The refinery of MOL, located in Hungary, requires regular ball valve and check valve replacements to maintain optimal performance. As a trusted check and ball valve supplier of MOL, DERVOS continues to provide ball valves for their operations. In this project, DERVOS supplied a batch of high-performance ball valves and check valves for fluid control in oil and gas applications. They required various types and specifications of ball and check to meet the operational and sealing requirements of different pipeline systems.
3" 1500LB axial flow check valve is made according to API 6D standard. The valve body is made of A995 4A. It has the structural characteristics of axial flow type, and structural length of 473mm. Its connection mode is RTJ.
DN50 PN40 check valve is made according to API 594 standard. The valve body is made of A105. It has the structural characteristics of dual plate and wafer type. Its connection mode is wafer.
10” 300LB Cast Steel Gate Valve is made according to API600 standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of Bolted Bonnet, Flexible Wedge and structural length of 457mm. Its connection mode is RF. And it has hand wheel operation mode. Product Parameters Type Cast Steel Gate Valve Size 10” Pressure 300LB Connection RF Operation Hand Wheel Body Material ASTM A216 WCB Design Norm API 600 Face to Face ASME B16.10 Screwed End ASME B16.5 Test & Inspection Code API 598 Temperature -29 ~ 425°C Applicable Medium Water, Oil and Gas Features 1.Manufactured from WCB cast steel, providing high strength and long service life for 300LB pressure class applications. 2.API 600 compliant gate valve with RF flange ensures reliable shutoff and secure installation in industrial piping systems. Technical Drawing Cast Steel Gate Valve Dimension Checking Pressure Testing Painting Nameplate & Packing Inspection Report
DN25 PN16 Forged Steel Floating Ball Valve is made according to ISO17292 standard. The valve body is made of ASTM-A105. It has the structural characteristics of Split Body, Floating Ball, Full Bore, Fire-safe, Anti-static, Blow-out Proof Stem. Its connection mode is RF . And it has hand wheel operation mode.
China 1 Inch Gate, Valve Manufacturer Dervos Provides 1 Inch Gate Valve, A105, API 600, Class 600, Flanged, Handwheel Operation.
8" 150LB butterfly valve is made according to API 609 standard. The valve body is made of WCB. It has the structural characteristics of double eccentric, high performance and zero leakage. Its connection mode is lug. And it has turbine operation mode.
24” 150LB Dual Plate Wafer Type Check Valve is made according to API 594 standard. The valve body is made of A216 WCB+SS316. It has the structural characteristics of Dual-plate wafer type, wafer body design. Its connection mode is Double flange, ASME B16.5.
Copyright © 2015-2026 DERVOS VALVE CO.,LTD.All Rights Reserved Blog / Sitemap / XML / Privacy Policy
