Check valves are often considered the most “quiet” yet essential components in a piping system. Their primary function is to prevent backflow and safeguard pumps, compressors, and the overall stability of the system. However, in real-world applications, poor sealing—commonly referred to as “leakage”—is one of the most frequent and frustrating issues encountered in check valve operation. When a check valve fails to seal properly, it can reduce system efficiency, trigger pressure fluctuations, cause water hammer, and even damage critical equipment. This article breaks down the technical causes behind check valve leakage and offers practical diagnostic and corrective measures to help you quickly identify and resolve sealing problems, even under challenging operating. 1. Why Does a Check Valve Fail to Close Properly? Common Causes Explained 1. Presence of Particles or Solid Impurities in the Medium Solid particles can become trapped between the disc and the seat, preventing full contact and causing slight or even noticeable leakage. Typical signs include: ● Significant leakage at small opening positions ● Leakage decreases after cleaning 2. Disc Wear or Seat Damage Frequent cycling, corrosive media, or high-velocity flow can wear the sealing surfaces, resulting in scratches, pits, or deformation. This issue is especially common in high-temperature steam systems. 3. Incorrect Installation Direction or Insufficient Tilt Angle Although it may sound like a basic mistake, incorrect installation still occurs on many job sites. Since check valves rely heavily on gravity and flow direction, improper installation prevents the disc from returning to its closed position smoothly. 4. Flow Velocity Too Low to Create Adequate Differential Pressure A check valve opens through fluid flow. When the flow rate is too low, the disc may flutter or fail to close completely, leading to leakage. Common scenarios include: ● Insufficient straight-pipe length ● Frequent pump start/stop ● Poorly designed low-flow systems 5. Disc Sticking or Hinge Mechanism Not Operating Smoothly In swing check valves, rust, corrosion, or lack of lubrication at the hinge pin or disc connection may cause sticking, preventing full closure. 6. Thermal Deformation of Sealing Surfaces Due to Temperature Fluctuations In high-temperature conditions such as steam service, thermal expansion and contraction can slightly deform sealing surfaces, resulting in an imperfect seal. 2. How to Quickly Determine If a Check Valve Is Not Closing Properly? 1. Abnormal Pressure Gauge Readings If the inlet pressure remains stable while the outlet pressure gradually rises, backflow caused by check-valve leakage is the most likely reason. 2. Pipe Vibration or Light Knocking Sounds This indicates that the disc is oscillating at high frequency, often due to insufficient flow velocity or a loose dis...
Recently, representatives from Dervos Valve visited long-term industrial valve partners in Norway, Italy, Germany, and Spain. The multi-day trip focused on understanding customers’ current project requirements and discussing future procurement plans and technical specifications in greater depth. In Norway, our team was invited to visit the customer’s equipment installation workshop and valve application site. Through direct discussions with the engineering and procurement teams, we gained a clear understanding of their concerns regarding high-pressure applications, material selection, and delivery schedules. The customer noted, “Dervos has an excellent grasp of our project needs. Your quick response and professional recommendations give us great confidence.” This feedback reflects not only trust in our product quality but also strong recognition of our service capabilities. The team then traveled to Italy for technical discussions with our local partners and visited their valve assembly and testing facilities. Our representatives introduced Dervos’s manufacturing capabilities, quality inspection processes, and ongoing product enhancements across ball valves, gate valves, butterfly valves, and check valves. The Italian customer remarked, “The solutions you presented are highly practical and will significantly improve the reliability of our projects.” Such positive feedback further strengthened the confidence in our partnership. Through this trip, Dervos gained deeper insights into the European market’s expectations regarding valve performance, quality control, and delivery reliability. We will continue to refine our products and services based on customer feedback, ensuring that every partner receives a reliable and fully tailored one-stop valve solution. Looking ahead, Dervos Valve will remain committed to our service philosophy of listening to customers, responding quickly, and delivering real value. With higher product standards and more professional technical support, we aim to strengthen and advance our cooperation with customers around the world.
Butterfly valves are widely used as regulating and shut-off devices in industrial piping systems, valued for their simple structure, lightweight design, and rapid open-close operation. They find applications across water treatment, chemical, metallurgical, power, oil, and gas industries. However, even high-quality butterfly valves can experience performance degradation if proper maintenance is neglected over long-term operation.This article explores the structural features, common issues, and maintenance practices to help effectively extend the service life of butterfly valves. 1. Understanding the Operational Characteristics of Butterfly Valves A butterfly valve primarily consists of a valve body, disc, stem, sealing elements, and an actuator. Its operation relies on the rotation of the disc, driven by the stem, to control fluid flow. During operation, the disc remains immersed in the fluid, subject to erosion, corrosion, and pressure shocks. Therefore, the valve’s lifespan is closely related to sealing performance, material selection, and the operating environment. 2. Common Factors Affecting Butterfly Valve Lifespan Frequent Operation and High Differential Pressure High-frequency cycling or prolonged operation under high pressure and flow velocity can cause valve seat wear and stem seal aging. Corrosive Media and Sediment Build-Up Chemical fluids or particulate-laden media can corrode the disc and clog sealing surfaces, reducing smooth operation. Improper Installation Misalignment between the valve and pipeline, or uneven bolt tightening, may lead to eccentric disc friction and damage to sealing elements. Lack of Regular Maintenance Neglecting routine cleaning and lubrication can increase operating torque, accelerate seal wear, and shorten the valve’s overall service life. 3. Maintenance Tips to Extend Butterfly Valve Lifespan 1. Proper Installation as the Foundation Ensure the valve body is aligned with the pipeline center to avoid eccentric stress. Use appropriate gaskets between the valve and flange to prevent localized stress. For actuated butterfly valves, confirm correct travel adjustment to avoid exceeding torque limits. 2. Regular Cleaning and Inspection Periodically remove deposits and debris from the disc surface to prevent seal surface damage. Check stem packing and seals; replace immediately if signs of aging are detected. For pipelines carrying particulate-laden media, flush the valve regularly to prevent clogging. 3. Lubrication and Corrosion Protection Apply grease to the stem, bearings, and drive components regularly to maintain smooth operation. For valves operating in seawater or corrosive environments, select corrosion-resistant coatings or materials such as aluminum bronze or duplex stainless steel. 4. Proper Operation and Control Avoid rapid or forced operation to prevent disc deformation from impact. If the ...
The 150LB ball valve, made of Duplex stainless steel 4A, has a special V port ball. The valve is particularly suitable for media containing fibers, tiny solid particles, slurry and so on.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
4AMethod of Operation:
Pneumatic actuatorQuick Details
|
Type |
Ball Valve |
|
Size |
1-1/2 Inch |
|
Pressure |
150LB |
|
Construction |
V port ball |
|
Connection |
Flange Connection |
|
Operation Mode |
Pneumatic Actuator |
|
Body Material |
ASTM A995 4A |
|
Ball Material |
ASTM A995 4A +Cr |
|
Design code |
API 608 |
|
Pressure & Temp |
API 608；ASME B16.34 |
|
End toEnd Code |
ISA S 75.04-1995 |
|
Inspection |
ISO 5208 |
|
Temperature Range |
-29℃~+120℃ |
|
Medium |
WOG |
General Description
A slotted ball and a V-Port ball with a small angle opening, such as a 15°ball, furnish a linear inherent flow characteristic. medium angle V-Port valves such as a 30°ball furnish a modified equal percentage inherent flow characteristic. Custom ports are also available to meet special control requirements.
Advantages
Flow control
The precision of V-Ball valves offers equal percentage flow characteristics that are generally not associated with a standard ball valve.
Bubble tight shut-off
V-ball valves have the capability of tight shut-off. Thus, additional shut-off valves are not required when using a V-ball valve over globe control valves.
Lower pressure drop
V-Ball valves also have higher flow coefficients (Cv) compared to the same size globe valve which diverts flow and uses a plug to control the flow through the valve. This means that smaller V-Ball sizes can be used to achieve the same flow rate as a larger size globe valve.
Higher shut-sff pressure
The 90°ball rotation allows the V-Ball to shut off at higher working pressures. Thus, allowing lower torque actuators to be used, resulting in cost-saving and higher efficiency for the end-user.
Technical Drawing
Witness Test
Nameplate
Product Application
Dervos valves can be widely used in varieties of industries, such as petrochemical, pipeline, oil & gas, marine, water treatment, power station industries and etc.
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The 12 inch 600LB trunnion mounted ball valve has gearbox, RTJ flange, fire safe design per API 607. The 3 piece ball valve is designed per API 6D. Design Feature & Benefit 1.Small flow resistance means less pressure drop 2.Simple valve structure and light weight 3.Diversified sealing material available, from metal material TCC, satellite, stainless steel to soft material PTFE, Teflon, Nylon, Peek and etc 4.Good performance of both metallic sealing and soft sealing 5.Convenient and swift operation of the valve 6.Easy to maintain due to renewable seat ring 7.When fully opened or closed, the valve sealing face is isolated from medium corrosion. 8.Wide range of application in terms of size and pressure rating Quick Detail Type Ball Valve Size 12" Pressure Class 600 Construction Trunnion Mounted Ball, Three-Piece Type, Side Entry Connection RF Flange Operation Gear Operated Body Material ASTM A105 Design & Manufacture API 6D Pressure & Temp ASME B16.34 Face to Face ASME B16.10 End Connection ASME B16.5 Test & Inspection Code API 598 Fire Safe API 607 Temperature Range -29℃~+200℃ Medium Water, Oil and Gas Origin China Material Specification No Part Name Carbon steel to ASTM Stainless Steel to ASTM WCB LCB CF8 CF8M CF3 CF3M 1 Underplate WCB LCB CF8 CF8M CF3 CF3M 2 Underplate Bolt A193 B7 A320 L7 A193 B8 3 Trunnion A182 F6 A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 4 Body A216 WCB A352 LCB A351 CF8 A351 CF8M A351 CF3 A351 CF3M 5 Bonnet Nut A194 2H A194 4 A194 8 6 Bonnet Bolt A193 B7 A320 L7 A193 B8 7 Cap A216 WCB A352 LCB A351 CF8 A351 CF8M A351 CF3 A351 CF3M 8 Gasket SS Spiral Wound/graphite or SS Spiral Wound/PTFE 9 Shaft Sleeve SS/graphite 10 Seat Ring RPTFE or POM 11 Ball A105/Ep.Cr or F6 A182 F6 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 12 Seat A105/Ep.Cr or F6 A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 13 Spring 17-17PH(inconel for NACE)Ni-cr Alloy 14 O-Ring Viton 15 Stem A182 F6 A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 16 Sealing Cover A182 F6 A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 17 O-Ring Viton 18 Gear Actuator The material is according to ASTM standard Related Knowledge What is difference between floating and trunnion ball valve? The ball part of floating ball valve is movable. Under the pressure of medium, the ball has a certain displacement and presses on the sealing surface of outlet end to ensure its tight sealing. The floating structure is suitable for ball valve with small size and low & medium pressure rating. The ball part of trunnion mounted ball valve is fixed. Under the medium pressure, the floating seat will move towards the ball to ensure the sealing. The trunnion mounted ball valve is often with larger size and higher pressure.
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.
Trunnion mounted ball valve DN300 PN63 full bore Double Block and Bleed PMSS seal(metal seal+soft seal）blowout proof stem gearbox operation with LF2 body, LF2+ENP ball/seat and 410 stem. Quick Detail Type Ball Valve Size DN300 Design Pressure PN63 Construction DBB,Trunnion mounted ball valve ConnectionType Flange OperationType Gearbox Operated Body Material LF2 Ball Material LF2+ENP Stem Material 410 Seat Material LF2 +ENP Design Code API 6D Face to Face Dimension API 6D End Connection ASME B16.5 Pressure & Temp ASME B16.34 Medium Water, Oil and Gas Origin China
API 6D ball valve is designed with trunnion mounted ball and full bore structure. The flanged ball valve has 300LB design pressure and 8 inch nominal size with gearbox operation mode, conforming to NACE MR0175 requirement. Quick Detail Type Ball Valve Size 8” Pressure 300LB Construction Two-Piece Body, Full Bore, Trunnion Ball Connection RF Flange Operation Mode Gearbox Body Material A216 WCB Trim Material Ball/Stem F6a, Seat RPTFE 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 Dervos Packing Painting Test & Report Pressure Testing & Dimension Checking
The API 6D ball valve is designed with trunnion mounted ball and full bore structure. The flanged ball valve has 600LB design pressure and 10 inch nominal size with gearbox operation mode, conforming to NACE MR0175 requirement.
The 4 inch 150LB ball valve is a 3-piece one with reduced port, A105 body, F6A stem, ball and seat. The The valve is made as per API6D and is tested under API 598.
China Carbon Steel Ball Valve Provider Offers 3 Piece Position Type Ball Valve, ASTM A105N, Class 800, 1 Inch, Free Floating Ball, API 608, BS 5351.
DN150 PN16 Ball Valve is made according to ISO 17292 standard. The fire resistance test meets the requirements of API 607 standard. The valve body is made of ASTM A105. Its operation mode is turbine operation. The trunnion mounted ball valve with a structural length of 400mm has the structural characteristics of full bore.
8" 2500LB ball valve is made according to API 6D standard. The valve body is made of F51. It has the structural characteristics of trunnion mounted ball, full bore. It also has the design of anti-fire, anti-static and anti-flying valve stem. In addition, it also meets NACE MR0175 requirements.
2" 1500LB ball valve is made according to API 6D standard. It also complies with the design standard of NACE MR0175. The valve body is made of ASTM-A105. It has the structural characteristics of full flow and trunnion mounted ball. It has RTJ connection mode and gearbox operation mode.
2" CL150 V-ball valve is made according to API 608 standard. The valve body is made of ASTM A995 4A. It has the structural characteristics of V type. It has RF connection mode, and its operation mode is polished rod torque.
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