A check valve is a critical device that prevents backflow, widely used in water treatment, oil & gas pipelines, chemical processing, and steam systems. After long-term operation, check valves may experience issues such as leakage, vibration noise, or sticking. If not addressed promptly, these problems can reduce system efficiency and even cause equipment damage or safety hazards. So, how can you tell if a check valve needs replacement? Which faults can be repaired, and which require a full replacement? This article provides a systematic guide. 1. Basic Operating Principle of Check Valves The primary function of a check valve is to automatically prevent backflow. When fluid flows in the intended direction, the valve disc is pushed open by pressure; when flow reverses, the disc closes automatically, using either its own weight or a spring, preventing backflow. Common types include: Lift Check Valve Swing Check Valve Dual Plate Wafer Check Valve Ball Check Valve Although their designs vary, the key criteria for determining whether a check valve needs replacement remain the same: sealing performance, operational smoothness, and structural integrity. 2. How to Determine if a Check Valve Needs Replacement Visible Leakage (Internal or External) If fluid continues to flow backward when the valve is closed, it indicates significant wear or deformation of the sealing surfaces, preventing an effective seal. If the leakage exceeds system tolerances and cannot be corrected by cleaning or resurfacing, the valve or its sealing components should be replaced. Sticking or Inflexible Valve Disc After long-term operation, the valve stem, guides, or disc may become stuck due to scaling, corrosion, or debris. If cleaning, descaling, or lubrication fails to restore smooth operation, replacement is recommended. Excessive Noise or Vibration Frequent opening and closing or rapid disc rebound can cause vibration or knocking sounds. This is usually due to spring failure, loose valve components, or worn guides. Persistent or frequent noise should trigger inspection of the valve’s structural integrity and consideration for replacement. Corroded or Cracked Valve Body or Cover Exposure to acidic, alkaline, or high-temperature fluids can corrode or crack the valve body, compromising structural strength and posing safety risks. Such damage cannot be repaired and requires full valve replacement. Frequent Backflow or Abnormal System Pressure Fluctuations Poor sealing or delayed valve response can cause system pressure variations, including water hammer. If repeated adjustments do not resolve the issue, it indicates aging of the internal spring or disc mechanism, necessitating timely replacement. 3. Common Fault Diagnosis and Solutions Fault: Valve fails to close completely, causing backflow Cause: Worn sealing surfaces, deformed disc, or trapped debris Solution: Remove ...
If you’ve ever hesitated between choosing a flanged or threaded globe valve, you’re not alone. Globe valves are common shut-off valves widely used in industries such as oil and gas, chemical processing, power generation, shipbuilding, and water treatment. While both connection types can control fluid flow, they differ significantly in terms of installation method, sealing performance, and suitable applications. This article will provide a systematic comparison of flanged and threaded globe valves from the perspectives of structure, performance, and application. I. Fundamental Difference in Connection Methods 1.Flanged Globe Valve A flanged globe valve connects to the pipeline through flanges, with bolts tightening the flange faces together to ensure a secure seal.This connection type offers excellent strength and reliability, making it ideal for medium to high-pressure, large-diameter, and frequently operated systems.In industrial applications, typical sizes range from DN50 to DN300, and flange dimensions generally follow international standards such as ANSI, DIN, or JIS. 2. Threaded Globe ValveA threaded globe valve typically uses either internal (NPT/BSP) or external threads to connect to the pipeline, relying on the threads themselves for sealing.This compact and lightweight structure allows for easy installation and is mainly used in small-diameter (usually ≤ DN50) and low-pressure systems, including residential pipelines.Because it does not require welding or flange gaskets, a threaded valve is more cost-effective in both installation and maintenance. II. Comparison of Sealing Performance and Maintenance Flanged Globe ValveFlanged globe valves typically use metal or flexible graphite gaskets for sealing, offering excellent resistance to high temperature, high pressure, and corrosion.During long-term operation, maintenance or valve replacement is straightforward—simply loosen the flange bolts to disassemble the valve. Threaded Globe ValveThe sealing of a threaded globe valve mainly depends on the thread engagement and sealing materials such as PTFE tape or sealing paste.However, repeated disassembly can damage the threads and increase the risk of leakage.For this reason, threaded globe valves are better suited for fixed installations, clean fluids, and low-pressure systems. III. Structural Dimensions and Installation Requirements Flanged Globe ValveFlanged globe valves are larger in size and require more installation space, but they provide superior vibration resistance and pressure tolerance.They are commonly used in industrial piping networks or pump station systems where sufficient structural support is available. Threaded Globe ValveThreaded globe valves feature a compact design, making them ideal for confined spaces or lightweight piping systems such as laboratories, compressor inlets and outlets, and domestic water supply lines.However, thr...
The global industrial valve market is undergoing a quiet yet significant transformation. Growth is no longer driven mainly by new construction projects — instead, it’s increasingly fueled by the replacement and modernization of aging equipment and infrastructure. From petrochemical plants to municipal water systems and natural gas pipelines, valve upgrades have become a key priority across industries. Aging Equipment Drives Rising Valve Replacement Demand In many industrial facilities, valves—though seemingly durable—gradually suffer from seal wear, sluggish operation, and leakage after years of service. For plants operating over a decade, valve degradation has become a major factor affecting safety and efficiency. With stronger focus on maintenance, process safety, and energy efficiency, end users in oil & gas, power, and water treatment sectors are accelerating valve replacement and upgrade projects. This trend aligns with a global shift toward predictive maintenance and sustainable operations, increasing demand for ball valves, gate valves, and control valves. Market research from Mordor Intelligence and others shows a shorter valve replacement cycle due to rising maintenance costs and downtime risks. Stricter environmental and safety standards are also pushing faster modernization worldwide. In the U.S., for example, the water sector—with pipelines averaging over 40 years old—is investing in large-scale valve renewal programs to reduce leakage and unplanned shutdowns. Similar initiatives are emerging across Europe and Asia. Infrastructure Investment Fuels Market Expansion Beyond replacements, ongoing infrastructure investment continues to drive valve demand globally. Asia’s rapid industrial growth and the Middle East’s refining and petrochemical expansion have led to increased valve procurement. According to GMI Insights, the global industrial valve market reached USD 75.9 billion in 2024 and is projected to hit USD 142.6 billion by 2034 (CAGR: 6.6%). Precedence Research forecasts even higher potential—up to 12.5% CAGR. This growth is backed by large-scale upgrades in urban water networks, wastewater treatment plants, natural gas pipelines, and energy transition projects such as hydrogen and carbon capture systems, all requiring next-generation high-performance valves. Valve Replacement Becomes a Smart Technology Upgrade Modern valves are evolving beyond mechanical parts. With smart manufacturing and the Industrial Internet of Things (IIoT), today’s valves feature sensors, smart actuators, and remote monitoring. Engineers can now track performance in real time and conduct predictive maintenance, reducing unexpected downtime. Advanced materials like corrosion-resistant alloys, cryogenic steels, and special polymers are extending service life and reliability—especially in harsh environments. For indu...
Payment:
30% T/T When Order, 70% T/T Before ShipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai ChinaLead Time:
35~60 days Ex Works After Order ConfirmationMaterial:
Carbon SteelMethod of Operation:
Gear Operated
Quick Detail
|
Type |
Butterfly Valve |
|
Nominal Size |
6 Inch |
|
Nominal Pressure |
Class 150 |
|
Structure |
Double Offset, Double Eccentric, Soft Seat |
|
Connection Type |
Lug Type |
|
Operation |
Gear Operated |
|
Design Code |
API 609 |
|
Face to Face |
ASME B16.10 |
|
End Connection |
ASME 16.5 |
|
Test & Inspection |
API 598 |
|
Body Material |
Cast Steel WCB |
|
Trim Material |
CF8M Disc, 17-4PH Stem, RPTFE Seat |
|
Application |
Water, Oil, Gas |
Dervos Inspection Report
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 double offset high performance butterfly valve, with lever operation and lug body, is designed per API 609. The CF8M body and PTFE seat butterfly valve is more durable in serving the application. Quick Detail Type Butterfly Valve Size 3'' Design Pressure 150LB Construction Double Eccnetric, Soft Seat Connection Type Lug Operation Wrench Operated Design Code API 609 Face to Face ASMEB16.10 End Connection ASMEB16.5 Test & Inspection API 598 Body Material Stainless Steel CF8M Temperature Range -29℃~+150℃ Application Water, Oil, Gas Dimension Class 150 DN mm 40 50 65 80 100 125 150 200 250 300 350 400 NPS in 1 1/2 2 2 1/2 3 4 5 6 8 10 12 14 16 L mm 127 127 127 127 152 203.2 203.2 203.2 203.2 in 5 5 5 5 6 8 8 8 8 L1 mm 38.1 46 50.8 48 54 63.5 57 63.5 71.5 81 92 101.5 in 1.5 1.81 2 1.88 2.13 2.5 2.25 2.5 2.81 3.19 3.62 4 H mm 185 190 220 229 239 252 284 307 337 392 435 481 in 7328 7.48 8.7 9 9.4 9.9 11.2 12 13.3 15.4 17.1 19 D(W) mm 160 160 160 160 160 160 160 200 200 250 250 300 in 6.3 6.3 6.3 6.3 6.3 6.3 6.3 7.9 7.9 9.8 9.8 11.8 Weight (Kg) mm 12.5 13.5 17 38 72 105 148 182 230 in 8 9 10 10 11 14.5 34.2 66 98 134 168 200 Related Knowledge What is a high performance butterfly valve? A high performance butterfly valve is often designed with double offset and PTFE seat, to handle everything from general applications to viscous and corrosive liquids; corrosive gases and steam. Compared to concentric resilient seat butterfly valve, the disc of the high performance butterfly valve is arranged and positioned off the center of the pipe bore, which could reduce wear and tear to the valve during operation and increase sealing performance. In conlusion, high performance butterfly valve is applicable for higher pressure and temperature applications. Meanwhile, it has longer cycle life and better sealing ability.
The 3 inch 150LB butterfly valve has a double-offset disc design that allows the disc to move off the seat reducing running torque and seat wear. The Wafer type valve can be driven by a gearbox and handwheel or by electric, pneumatic or hydraulic actuator.
12" 300LB butterfly valve is made according to API 609 standard. The valve body is made of WCB. It has the structural characteristics of high performance and double eccentric. Its operation is turbine operation and packing is graphite.
DN900 150LB Triple Offset Metal Seated Butterfly Valve is made according to API609 standard. The valve body is made of C95500. It has the structural characteristics of Triple offset, bidirectional equal pressure zero leakage. Its connection mode is FF double flange. And it has Turbine operation mode.
6" 150LB basket strainer is made according to ASME B16.34 standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of basket style, bolted cover, with exhaust and drain plugs. Its connection mode is RF.
The 6 Inch PSB globe valve has 1500LB design pressure, butt weld end, and gearbox. The full bore globe valve is made of carbon steel WCB body and trim 5 material. Quick Detail Type Globe Valve Size 6'' Design Pressure Class 1500 Construction Pressure Seal Bonnet, Plug Type Disc, Rising Stem Connection Type Butt Weld Operation Type Bevel Gearbox Opearted Design Code BS 1873 End to End ASME B16.10 Connection End ASME B16.25 Pressure & Temperature ASME B16.34 Test & Inspection Standard API 598 Body Material Cast Steel WCB Trim Material Trim NO. 5 Temperature Range -29℃~+425℃ Application WOG Origin China Material & Dimension NPS DN Class 2 2 1/2 3 4 6 8 50 65 80 100 150 200 L(RF) L1(BW) 900LB 368 419 381 457 610 737 1500LB 368 419 470 546 705 832 2500LB 451 508 578 673 917 1022 L2(RTJ) 900LB 371 422 384 460 613 740 1500LB 371 422 473 549 711 841 2500LB 454 514 584 683 927 1038 H(Opne) 900LB 550 605 678 798 930 1230 1500LB 550 605 866 956 1260 1263 2500LB 560 720 755 1230 1791 2086 W 900LB 350 350 400 450 458 610* 1500LB 400 400 450 560 610* 610* 2500LB 400 450 560 310* 610* 760 Weight (RF) 900LB 78 108 102 142 400 960 1500LB 85 110 135 230 660 1590 2500LB 140 168 247 620 1500 3200 Weight (BW) 900LB 66 91 87 128 355 868 1500LB 77 101 122 209 595 1440 2500LB 100 118 180 438 1148 2594 *Manual gear operator is recommended 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 Seat Ring A105 A182 F11 A182 F22 A182 F5 A182 F304 A182 F316 A182 F304L A182 F316L 3 Disc A105 A182 F11 A182 F22 A182 F5 A182 F304 A182 F316 A182 F304L A182 F316L 4 Stem A182 F6 A182 F304 A182 F304 A182 F316 A182 F304L A182 F316L 5 Disc nut A182 F6 A182 F304 A182 F304 A182 F316 A182 F304L A182 F316L 6 Cap SS Spiral Wound graphite or SS Spiral Wound PTFE 7 Body Seal Flexible Graphite+316 8 Adjustment Gasket F6 F6 F316 9 Stem packing Flexible Graphite+316 10 Gland Nut A194 2H A194 8 11 Gland Eyebolt A193 B7 A193 B8 12 Pin Carbon steel or Stainless Steel 13 Cap Nut Carbon steel or Stainless Steel 14 Gland A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 15 Gland Flange A216 WCB A351 CF8 16 Yoke A216 WCB A351 CF8 17 Stem Nut A439 D2 or B148-952A 18 Screw Carbon steel 19 Handwheel Ductile Iron or carbon steel 20 Name Plate Stainless steel or Aluminum 21 Washer Carbon steel 22 Nut Carbon steel or Stainless Steel Related Knowledge Why do we use pressure seal bonnet? Pressure sealed bonnet are often used for valves with high design pressure. The higher the internal pressure gets, the greater the sealing force beween body and bonnet become. For bolted bonnet valves, the body and bonnet are joined by studs and nuts with a gasket between the flange faces to facilitate sealing. However,as system pressure increases,the potential for leakage through the body and bonnet increases. But for pressure sealed valve, “bonnet take-up bolts” to pull the bonnet up and seal against the pressure seal gasket. That is why when pressure increase, the performance of pressure seal gasket between body and bonnet becomes better.
DN400 PN10 check valve is made according to DIN standard. The valve body is made of WCB. It has the structural characteristics of swing type and structural length of 310mm. It has the connection mode of RF. This valve has a built-in damper, which is mainly used for shock absorption and energy dissipation.
The 1 inch swing check valve has the construction of bolted bonnet and RF flange end. The forged steel swing check valve is designed with reduced bore as per API 602. Dervos could also do customizing service as per clients’ requests on sizes, design ratings, materials, and standards and so on.
DN25 PN100 Forged Steel A105 NPT Connection Way 2 Pieces Construction Full Pore Lever Operation Floating Ball Fire Safety Body and Bonnet A105 Ball a182 F304 Seat Ring PTFE Stem A182 F304 Stem O Ring Viton Packing Graphite Gland Stainless Steel Design and Manufacture ASME B16.34 Face to Face Design Manufacture Standard Manufacture Standard Screw and Dimension ANSI B1.20.1 Inspection and Test API598 Fire Safety Design API 607 Quick Detail Type Ball Valve Size DN25 Pressure PN100 Construction 2 Pieces Connection NPT Operation Mode Lever Body Material A105 Cover A105 Design & Manufacture ASME B16.34 End to End ASME B16.10 End Connection ANSI B1.20.1 Inspection API 598 Temperature Range -29℃~+538℃ Medium Oil, Water, Gas
DN50 PN25 Forged Steel Gate Valve is made according to BS5352 standard. The valve body is made of A105N. It has the structural characteristics of Bonnet、Solid Wedge. Its connection mode is BW. And it has hand wheel operation mode.
DN800 PN10 gate valve is made according to DIN standard. The valve body is made of GGG50. It has the structural characteristics of F4 drinking water soft gate. Its connection mode is RF, and it has gear operation.
Quick Detail Type Globe Valve DN DN50 PN PN250 Construction Tee Pattern; Bolt Bonnet; Connection Type NPT Operation Type Handwheel Design Code API602 Screw End ASME/ANSI B1.20.1 Test & Inspection API598 Body Material A105+STL Trim Material A276-420 Medium Water, Oil and Gas Origin China Features -- Globe valves have both good throttling and shutoff capabilities -- Easy to maintain and resurface the seats -- Can be used as a stop-check valve if the disc is not attached to the stem Technical Drawing Dimension Check Witnessing Tests Dervos Packaging Good packing means good first impression. Just imagine how do you feel differently when seeing two boxes below? And you will know the reason why in Dervos we value packaging so much. In Dervos, we make sure- Every valve is clean and dry. -Clean the valve before packing -Add anti-rust oil -Add flange cover No damage to valves in delivery. -Fix the valve with iron wire -Separate the valve with soft material -Layer the valve with plywood -Strong box and clear shipping mark
Copyright © 2015-2025 DERVOS VALVE CO.,LTD.All Rights Reserved Blog / Sitemap / XML / Privacy Policy
