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:
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.
10" 150LB check valve is made according to BS1868 standard. The valve body is made of ASTM UNS N08031. It has the structural characteristics of bolt cover and swing type. Its connection mode is FF.
DN25 PN64 forged steel globe valve is made according to BS 5352 standard. The valve body is made of F321. It has the structural characteristics of Bolted Bonnet, Straight-through Type, Extended Stem 100 mm, with Low-leakage Packing. Its connection mode is EN1092-1 B1. And it has hand wheel operation mode. Product Parameters Type forged steel globe valve Size DN25 Pressure PN64 Connection EN1092-1 B1 Operation Hand Wheel Body Material A182 F321+STL Design Norm BS 5352 Face to Face EN 558 Flange dimension EN 1092 Test & Inspection Code EN 12266 Temperature -50 ~ 150°C Applicable Medium Water, Oil and Gas Features 1.Forged from F321 stainless steel, providing excellent high-temperature resistance and corrosion durability for PN64 pressure applications. 2.Globe valve design with hand wheel operation ensures precise flow control and reliable shutoff. Technical Drawing Forged Steel Globe Valve Dimension Checking Pressure Testing Spectrum
8" 2500LB DBB Trunnion Mounted Ball valve is made according to API 6D standard. The valve body is made of A182 F51. It has the structural characteristics of DBB Fixed Ball Valve, Full Bore, Fireproof/Electrostatic/Anti-Exposed Stem Design, Compliant with NACE MR0175. Its connection mode is RTJ. And it has Turbine operation mode with locking device.
Bolt bonnet Gate valve follow EN1984 design standard, raised face flanged connection, outside screw and yoke, handwheel operation, GP240GP body/bonnet/wedge material, F6a stem, metal seal/seated. Quick Detail Type Gate Valve Size DN200 DesignPressure PN40 Construction Bolt Bonnet Gate Valve Connection Type Raised Face Flange Connection Operation Handwheel Design Code EN 1984 Face to Face DIN 3202 End Connection EN 1092-1 Test & Inspection EN 12266-1 Body Material GP240GH Temperature Range -29~425℃ Application WOG
DN80 PN25 Cast Steel gate valve is made according to BS EN 1984 standard. The valve body is made of EN 10213 1.0619. It has the structural characteristics of insulation jacket with DN15 small flange. Its connection mode is EN1092-1 B. And it has Hand Wheel operation mode.
6"X4" 90LB ball valve is made according to ASME B16.34 standard. The valve body is made of A105. It has the structural characteristics of reduced diameter, fixed ball, DIB-1, fireproof, anti-static, 3-piece. Its connection mode is RTJ. And it has worm wheel operation mode.
The basket type strainer has 150LB design pressure and 1 1/2 inch size. The flanged strainer is made of LCC body and stainless steel screen. Quick Detail Type Strainer Size 1.5'' DesignPressure 150LB Construction Bolted Bonnet, Basket Type ConnectionType Flanged Design Code ASME B16.34 Face to Face ASME B16.10 End Connection ASME B16.5 Pressure & Temp ASME B16.34 Test & Inspection API 598 Body Material ASTM A352 LCC ScreenMaterial SS304 TemperatureRange -46℃~+345℃ Application Water, Oil, Gas Company Profile Founded in Xiamen in 2008, DERVOS VALVES INDUSTRY CO., LTD has accumulated rich experience in supplying and exporting industrial valves, from general types of gate valve, globe valve, check valve, ball valve, butterfly valve, plug valve, strainer to special valves like needle valve, control valve, relief valve, safety valve and steam trap. Dervos people are committed to provide our customers with best possible service and valve products at a competitive price. With over 500 valve suppliers, the rich resources we own enable us to find the most suitable products in a very short time for our customers. Purchasing System Dervos purchasing system plays an important role in order follow up and supplier management. What does our purchasing team do? -Confirm production plan with the factory -Follow up the order according to the production plan very closely -Take every measure to initiate all related resources to solve the delay crisis -Seek new suppliers and put them into our supplier pool by evaluating them on quality, equipment, certificates, price level, technical supports etc -Do annual evaluation on current suppliers and eliminate those unqualified ones. All these actions will make sure that clients’ order will be delivered on time and we can find most suitable products among qualified suppliers in an efficient way.
3/4” 150LB Y Type Strainer is made according to ASME B16.34 standard. The valve body is made of F53. It has the structural characteristics of BB. Its connection mode is NPT.
4" 150LB gate valve is made according to API 603 standard. The valve body is made of ASTM A351 CF8M+STL. It has the structural characteristics of bolt cover, elastic wedge and rising stem. Its test and inspection conform to API 598, and its operation mode is handwheel operation.
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