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 ...
This year’s Dervos annual conference was noticeably more grand and well-organized than in previous years. In the morning session, each department delivered its annual work summary, reviewing key projects and achievements over the past year. Teams also openly shared the challenges encountered during implementation and the practical experience gained along the way. Through this cross-department exchange, everyone developed a clearer understanding of one another’s responsibilities and workflows, laying a stronger foundation for future collaboration and communication. In the afternoon session, the Outstanding Employee awards were presented. Each nominee shared their work achievements and practical experience, demonstrating a strong sense of responsibility and execution across different roles. It is precisely this proactive mindset, collaborative spirit, and down-to-earth working approach of Dervos employees that drives the team steadily toward its shared goals. Showing up on time every single day throughout the year — that’s quite an achievement. Ian has now received the Perfect Attendance Award for two consecutive years. During the annual conference, Dervos also presented medals and exclusive commemorative gifts to employees who have completed five years of service. Dervos values the long-term dedication and consistent commitment of its team members, and sincerely appreciates the trust and contributions they have made over the years. For many at Dervos, the company is not only a platform for professional growth, but also a stage where shared goals and collective efforts come to life. In the evening, the annual conference transitioned into the banquet segment. Performances and interactive games were seamlessly interspersed, creating a relaxed yet organized atmosphere. Laughter and cheers echoed throughout the venue, and in the moment the camera shutter clicked, the excitement and joy were captured in a single frame. Eric said: "Let’s dream together, DERVOS's dream. A dream where we all play a part, piece by piece, it becomes a reality." For Dervos, the annual meeting is not just about "summarizing the year," but about bringing our hearts together, strengthening our resolve in doing the same thing, and then continuing to move forward, step by step, with steady progress.
Ball valves and plug valves differ significantly in several aspects, including structure, operating principle, mode of operation, flow control capability, sealing performance, and application scenarios. These differences enable the two types of valves to perform distinct roles in their respective fields. Structural Differences The ball valve, a design evolved from the plug valve, utilizes a spherical element as its core component. By rotating the ball 90° around the stem axis, the valve can be opened or closed. Its structure is straightforward, consisting primarily of a spherical closure element with a through-bore housed within the valve body. In contrast, the structure of a plug valve is more complex. It comprises multiple components such as the valve body, bonnet, plug, seat, and stem. The closure element is a cylindrical or tapered plug that controls flow by rotating 90°, aligning or misaligning the port in the plug with the flow passage in the valve body to achieve opening or shutoff. Operating Principle The operating principle of a ball valve relies on the rotation of the ball to control the on-off flow of fluid. When the ball is in tight contact with the valve seat, the clearance between them is completely sealed, thereby preventing fluid leakage. When the ball rotates to a position disengaged from the seat, the fluid is allowed to flow freely through the passage inside the valve body. The operating principle of a plug valve differs in that it primarily controls the flow passage by rotating the plug element to open or close the valve. In a plug valve, the plug is connected to the stem and rotates together with it to achieve flow control. The closure element is a tapered plug with a port, and the flow passage is designed to be perpendicular to the axis of the plug. This configuration enables the plug valve to operate more efficiently and reliably during opening and closing. The operation of a ball valve is notably simple, requiring only a 90-degree rotation to achieve opening or closing. This design allows the flow passage to be opened or shut off quickly and smoothly when the ball is rotated by 90 degrees, providing both convenience and efficiency. In addition, ball valves offer relatively low flow resistance in the fully open or fully closed position, making them particularly suitable for applications that require rapid on-off operation. By contrast, the operation of a plug valve is comparatively more complex, as several turns are typically required to complete the opening or closing action. The valve plug is designed in a cylindrical or tapered form and regulates fluid flow through rotation. Nevertheless, plug valves demonstrate excellent performance in flow regulation, enabling precise adjustment of the flow passage diameter and accurate control of flow rate. However, due to the relatively complicated operating process, plug valves are not well suited for frequent operation...
The gate valve, made according to API 600, is made of CF8, one kind of cast steel. The 4 inch valve is equipped a handwheel, outside yoke, bolted bonnet and extended bonnet. All the accessories are traceable.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
CF8Method of Operation:
Handwheel
Quick Details
|
Type |
Gate Valve |
|
Size |
4 Inch |
|
Design Pressure |
600LB |
|
Construction |
B.B; OS&Y; Extended Bonnet |
|
Connection Type |
Bolt Welded |
|
Operation Type |
Handwheel |
|
Body Material |
CF8 |
|
Disc Material |
CF8+STL |
|
Design Code |
API 600 |
|
Flange Ends |
ASME B16.25 |
|
Face to Face |
ASME B16.10 |
|
Inspection and Test |
API 598 |
|
Temperature |
-196~539℃ |
|
Medium |
Water, Oil and Gas |
|
Origin |
China |
Features
-Full Bore Design
-Superior flow rates & small friction loss
-Low torque value for closing and opening the valve
-Flexible wedge for better seating and easy operation
-Smooth finish and superior sealing for seat face
-Every valve is manufactured with specific number on body for traceability
Technical Drawing
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.
Made of stainless steel, the cryogenic gate valve has extended bonnet, reduced bore, non-rising handwheel, socket weld connection, complying with API 602. Quick Detail Type Gate Valve Size 1'' Design Pressure ANSI 1500 Construction Extended Stem, Bolted Bonnet, Solid Wedge ConnectionType Socket Weld (SW) OperationType Handwheel Operation Body Material A182 F316L TrimMaterial SS316L Design Code ASME B16.34 Face to Face ASME B16.10 End Connection ASME B16.11 Medium Water, Oil and Gas Origin China Available Modifications for Dervos Valves -Design Pressure -Nominal Diameter -Body Material & Trim Material -Material & Type for Packing and Gasket -Valve Operation Type -Modifications of End Connection -Available Extended Stem or Bonnet -Available By-Pass Valve -Customized Coatings & Packaging Related Knowledge Why do we use extended stem for cryogenic valves? The cryogenic valves are mainly used in low temperature liquid media, like liquefied natural gas and petroleum products. The reasons why we use extended stem for cryogenic valves are as below: 1.To maintain the temperature of stem packing in a proper level, since the very low temperature will influnce the sealing function of stem pakcing. 2.To prevent the heat outside from entering the valve and cause energy loss to the application 3.The long stem structure facilitates the quick replacement of the valve's main part through the valve cover. 4.To prevent the parts (like handwheel) over stem from freezing
16" x 12" 600LB trunnion mounted ball valve is made according to API6D standard. The valve body is made of A105. It has the structural characteristics of split type, side mounted, fixed ball, reduced diameter. Its connection mode is RF. And it has pneumatic operation mode.
The 16 inch triple offset butterfly valve is designed with metal seat, stainless steel CF8M body, disc and stem. The fully lugged butterfly valve with gearbox has Class 150 design pressure as per API 609. Design Feature 1. Small volume, light weight, simple structure 2. Multi-layer metal seated/fully metal seated 3. Firesafe design 4. Anti-blowout stem 5. Small torque value for operating easily 6. Reliable sealing and could meet zero leakage requirement 7. With function of regulating flow 8. Triple eccentric design for minimized wear of sealing face Quick Detail Type Butterfly Valve Size 16'' Pressure ANS 150 Structure Triple Eccentric, Triple Offset, Metal Seated Connection Type Lug Type Operation Gearbox Operated Design Code API 609 Face to Face ASME B16.10 End Connection ASME B16.5 Test & Inspection API 598 Body Material A351 CF8M Temperature Range -29℃~+425℃ Application Water, Oil, Gas Material No Part Name Carbon steel to ASTM Alloy steel to ASTM Stainless steel to ASTM WCB WC6 WC9 C5 CF8 CF8M CF3 CF3M 1 Body A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 2 Below Axle Bush PTFE or Stainless Steel and Graphite Spiral Wound 3 Stem A182 F6 A182 F304 A182 F304 A182 F304 A182 F304 A182 F316 A182 F304L A182 F316L 4 Seat Ring F6 Stellite 6 Stellite 6 Stellite 6 A182 F304 A182 F316 A182 F304L A182 F316L 5 Butterfly Plate A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 6 Lock Ring A105 A182 F22 A182 F22 A182 F22 A182 F304 A182 F316 A182 F304L A182 F316L 7 Pin Carbon Steel or Alloy Steel 8 Screw Carbon Steel or Alloy Steel 9 Top Axle Bush PTFE or Stainless Steel and Graphite Spiral Wound 10 Packing Graphite+SS304 11 Bolt A193 B7 A193 B7 A193 B7 A193 B7 A193 B8 A193 B8 A193 B8 A193 B8 12 Nut A194 2H A194 2H A194 2H A194 2H A194 Gr.8 A194 Gr.8 A194 Gr.8 A194 Gr.8 13 Bolt A193 B7 A193 B7 A193 B7 A193 B7 A193 B8 A193 B8 A193 B8 A193 B8 14 Nut A194 2H A194 2H A194 2H A194 2H A194 Gr.8 A194 Gr.8 A194 Gr.8 A194 Gr.8 15 Yoke A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 16 Gland A182 F6 A182 F304 A182 F304 A182 F304 A182 F304 A182 F316 A182 F304L A182 F316L
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.
The cast steel lift non return check valve is designed with piston type disc, bolted bonnet, and PN16 RF flange. The spring loaded check valve conforms to DIN 3356. Quick Detail Type Check Valve ( Non-return Valve) Nominal Diameter DN 150 NominalPressure PN 16 Construction Lift Type / Piston Type, Bolted Bonnet Connection Flanged Connection Design & Manufacture DIN 3356 End to End EN 558 Connection EN 1092 Test & Inspection EN 12266 Body Material Carbon Steel GS C25 Media W.O.G. Product Range Body material: CS, SS, Alloy Steel, CI, Bronze, Brass Size Range: 2”~12” (DN50~DN300) End Type: Butt Weld, Socket Weld, Flanged, Screwed Pressure Range: 150lbs~2500lbs (PN16~PN420) Temperature Range: -46℃~ +425℃ Related Knowledge What is a piston check valve? Usually, we have swing type check valve and lift type check valve. A piston check valve and ball check valve both belong to lift type check valve. In a lot of cases, a piston check valve use spring to retain the disc in closed position. The structure of a piston check valve is very similar to the globe valve just without manual operation. Due to its piston type disc and superior leak tight characteristic, the piston check valves are suitable for small size and high pressure conditions.
DN100 PN40 Stainless Steel Gate Valve is made according to EN 1984 standard. The valve body is made of X6CrNiMoTi17-12-2. EN 1.4571 (AISI 316Ti) is widely used in medium- to high-temperature applications where resistance to intergranular corrosion and moderate chloride corrosion is required, especially in welded systems without post-weld heat treatment. Its connection mode is EN558. And it has Hand Wheel operation mode. Product Parameters Type Stainless Steel Gate Valve Size DN100 Pressure PN40 Connection EN 558 Operation Hand Wheel Body Material X6CrNiMoTi17-12-2 Design Norm EN 1984 Face to Face dimension EN 1092 End connection EN 558 Test & Inspection Code EN 12266-1,2 Temperature -29 ~ 425°C Applicable Medium Water, Oil and Gas Features 1.Made from EN 1.4571 stainless steel, offering excellent corrosion resistance and high-temperature stability for PN40 pressure applications. 2.Gate valve design compliant with EN 1984 ensures reliable shutoff and long service life in industrial piping systems. Technical Drawing Dimension Checking Pressure Testing Spectrum Nameplate & Packing
China Wafer Type Butterfly Valve Provider DVS Supplies Cast Steel Wafer Butterfly Valve, 2 Inch, Class 300, Lever Operation, for Air, Water, Steam and Gases.
11/2" 800LB globe valve is made according to API602 standard. The valve body is made of A105+STL. It has the structural characteristics of welded bonnet. Its connection mode is SW. And it has hand wheel operation mode.
The Class 300 flanged ball valve has cast steel WCB body, stainless steel ball, stem, seat ring along with Devlon seat insert. We also supply more types of trunnion mounted ball valve, accept customized. Design Feature 1.Firesafe design as per API 607 2.With sealant injection for self lubricating 3.With antistatic design 4.With anti-blowout stem 5.With vent and drain port 6.Full bore design 7.Three-piece type and trunnion ball 8.Gear operated for easy operation Quick Detail Type Ball Valve Size 24" Pressure ANSI 300 Construction Trunnion Type Ball, 3-Piece Body, Side Entry, Full Bore Connection Flange Connection Operation Gearbox Operation Body Material ASTM A216 WCB Design Code API 6D Pressure & Temp Code ASME B16.34 Face to Face ASME B16.10 End Connection ASME B16.5 Test & Inspection Code API 598, API 6D Fire Safe API 607 Temperature Range -29℃~+200℃ Medium WOG Origin China Dimension CLASS 300 DN mm 50 65 80 100 150 200 250 300 350 400 450 500 600 700 NPS in 2 2.5 3 4 6 8 10 12 14 16 18 20 24 28 L (RF) mm 216 241 283 305 403 502 568 648 762 838 914 991 1143 1346 in 8.5 9.5 11.13 12 15.88 19.75 22.38 25.5 30 33 36 39 45 53 L1 (BW) mm 216 241 283 305 457 521 559 635 762 838 914 991 1143 1346 in 8.5 9.5 11.13 12 18 20.5 22 25 30 33 36 39 45 53 L2 (RTJ) mm 232 257 298 321 419 518 584 664 778 854 930 1010 1165 1372 in 9.13 10.13 11.75 12.63 16.5 20.38 23 26.13 30.63 33.63 36.63 39.75 45.89 54 H mm 153 165 195 213 272 342 495 580 625 720 790 840 1050 1150 in 6.02 6.5 7.68 8.39 10.7 13.5 19.5 22.85 24.6 28.35 31 33.1 41.34 45.3 Do(W) mm 400 400 600 850 1100 1500 *350 *350 *600 *600 *800 *800 *800 *800 in 15.74 15.74 23.62 33.46 43.3 59 13.8 13.8 23.6 23.6 31.5 31.5 31.5 31.5 RF(Kg) 18 27 47 80 118 200 365 530 740 1030 1320 1540 2600 3900 BW(Kg) 14 2 38 65 105 185 342 503 713 1000 1285 1498 2540 3825 *Worm Gear or Electric Actuator Operated Dervos Quality Checking System In Dervos, we control quality throughout the whole manufacturing process. Casting inspection: Though casting inspection, we can find out the problem of raw material, such as shoddy casting, unqualified wall thickness, chemical composition and so on, which ensure that you will not be cheated. Machining Inspection: On the one hand, we could ensure machining accuracy through this process. On the other hand, we can find out machining mistake as early as possible, to win more time for repairing and remaking Final Inspection: Final inspection activities include document and QC record review, visual examination, dimension check, pressure test, painting and packing check. You don’t need to come and inspect in person and all the documents could be provided as proof.
12" 150LB dual plate wafer check valve is made according to API594 standard. The valve body is made of WCB. It has the structural characteristics of double disc and structural length of 181mm. Its connection mode is wafer.
3/4" PN16 floating ball valve is made according to ASME B16.34 standard. The valve body is made of A105. It has the structural characteristics of floating ball, full bore, anti-fire and anti-static. Its connection mode is M NPT. And it has lever operation mode.
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