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...
The high-pressure
Class 4500 gate valve is designed with PSB and SW end connection. Made of CS
A105, the 2 inch gate valve follows the inspection standard API 598 and design
standard API 602.
Dervos could offer customizing service by providing clients with valves in
different sizes, materials, standards, design pressure, structure, operation
type and connection type.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
CS A105Product Description
|
Type |
Gate Valve |
|
Size |
2" |
|
PN |
Class 4500 |
|
Construction |
Pressure Seal Bonnet, OS&Y |
|
Connection |
SW |
|
Operation |
Handwheel |
|
Body |
CS A105 |
|
Design Standared |
API 602 |
|
Face to Face Code |
ANSI B16.10 |
|
Pressure & Temp |
ANSI B16.34 |
|
Test & Inspection |
API 598 |
|
Temp. |
-29℃ ~ +425℃ |
|
Medium |
Water, Oil and Gas |
|
Origin |
China |
Material
Product Range
Our products include different kind of valves as below. Or you want to know more detail, just contact us.
Quality Inspection
Dervos strictly controls product quality. In addition to the final round of inspections, our quality inspection team also checks valve quality through casting or forging, machining, pressure testing, dimensional inspection, painting and packaging.
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 8 inch Class 2500 gate valve is designed with pressure seal bonnet, butt weld connection, and gearbox operation. The 8 inch gate valve has carbon steel WCB body and trim 5. Quick Detail Type Gate Valve Size 8'' Design Pressure ANSI 2500 Construction Pressure Seal Bonnet, Flexible Wedge, Metal to Metal Seat ConnectionType Butt Weld (SW) OperationType Gearbox Operation Body Material A217 WC6 TrimMaterial Trim 5 Design Code API 600 Face to Face Dimension ASME B16.10 End Connection ASME B16.25 Pressure & Temp ASME B16.34 Medium Water, Oil and Gas Origin China Dimension & Material NPS DN Class 2 2 1/2 3 4 6 8 10 12 14 16 18 20 24 50 65 80 100 150 200 250 300 350 400 450 500 600 L(RF) 900LB 368 419 381 457 610 737 838 965 1029 1130 1500LB 368 419 470 546 705 832 991 1130 1257 1384 2500LB 451 508 578 673 917 1022 1270 L1(BW) 900LB 216 254 305 355 508 660 787 914 991 1092 1346 1473 1600 1500LB 216 254 305 406 559 711 864 991 1067 1194 1697 2500LB 279 330 368 457 610 762 914 1041 1118 1245 L2(RTJ) 900LB 371 422 384 460 613 740 841 968 1038 1140 1500LB 371 422 473 549 711 841 1000 1146 1276 1407 2500LB 454 514 584 683 927 1038 1292 H(Opne) 900LB 554 637 680 796 1084 1372 1494 1550 1960 2210 1500LB 554 637 767 875 1094 1372 1655 1834 2150 2260 2460 2721 2940 2500LB 610 654 753 850 1254 1374 1685 1894 2226 2382 2585 W 900LB 300 350 350 400 560 460* 610* 610* 610* 760* 1500LB 300 450 450 560 305* 460* 610* 610* 760* 760* 2500LB 500 500 600 600 460* 460* 610* Weight (RF) 900LB 50 84 92 154 341 622 950 1295 1720 2380 1500LB 60 91 128 182 394 795 1370 2120 2800 3870 2500LB 121 175 195 229 720 1295 2250 Weight (BW) 900LB 39 64 82 120 266 524 760 1090 1450 2018 1500LB 46 71 85 130 292 578 974 1615 2010 2815 3315 4150 5219 2500LB 88 135 144 158 500 892 1550 1978 2580 3780 5988 *Manual gear operator is recommended No. Part WCB WC6 WC9 C5 CF8 CF8M 1 Body A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M 2 Seat A182 F6a A182 F22 A182 F22 A182 F5 A182 F304 A182 F316 3 Wedge A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M 4 Stem A182 F6a SAEHNV3 A182 F304 A182 F316 5 Stuffing Box A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M 6 Seal Ring ANSI 316L Flexible Graphite+316 7 Split Ring Steel F6 F6 F6 A182 F304 F316 8 Back Ring Steel Steel Steel Steel SS SS 9 Bolt A193 B7 A193 B7 A193 B7 A193 B7 A193 B8 A193 B8 10 Nut A194 2H A194 2H A194 2H A194 2H A194 Gr.8 A194 Gr.8 11 Yoke A216 WCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M 12 Bolt A193 B7 A193 B7 A193 B7 A193 B7 A193 B8 A193 B8 13 Nut A194 2H A194 2H A194 2H A194 2H A194 Gr.8 A194 Gr.8 14 Packing Plate ANSI 410 ANSI 410 ANSI 410 ANSI 410 ANSI 304 ANSI 316 15 Packing Flexible Graphite(Braided and Ring) or PTFE 16 Split Pin Steel Steel Steel Steel Steel Steel 17 Eyebolt A193 B7 A193 B7 A193 B7 A193 B7 A193 B8 A193 B8 18 Gland A182 F6 A182 F6 A182 F6 A182 F6 A182 F304 A182 F316 19 Gland Flange A105 A105 A105 A105 A182 F304 A182 F316 20 Nut A194 2H A194 2H A194 2H A194 2H A194 Gr.8 A194 Gr.8 21 Stud A193 B7 A193 B7 A193 B7 A193 B7 A193 B7 A193 B7 22 Stem Nut Ni-resist A439-D2 23 Gear Box Purchased 24 Protector Steel 25 Nameplate ANSI 304 26 Rivet ANSI 304
8" 1500LB gate valve is made according to ASME B16.34 standard. The valve body is made of WCC. It has the structural characteristics of pressure self sealing, elastic gate and structural length of 711mm. The working principle of self sealing valve is mainly to use wedge sealing surface to seal under pressure.
10'' 1500LB gate valve is made according to ASME B16.34 standard. The valve body is made of WCC. It has the structural characteristics of pressure self sealing, rising stem, elastic wedge and structural length of 864mm. Both ends of the valve stem are threaded. It has BW connection type.
The stainless steel non return valve features in non slam type disc, INCONEL X750 spring, WCB valve body. This valve owns an excellent dynamic performance and minimizes vibrations and noise.
1/2" 6000PSI needle valve is made according to ASME B16.34 standard. The valve body is made of SS316. It has the structural characteristics of straight through. Its connection mode is FNPT. And it has lever operation mode.
2" 800LB swing check valve is made according to API 602 standard. The valve body is made of ASTM A105N. It has the structural characteristics of bolted cover, swing type. Its connection mode is NPT.
4 Inch 150LB Cast Steel Swing Check Valve is made according to API 6D standard. The valve body is made of ASTM A351 CF8M. It has the structural characteristics of Swing Type, External Pin. Its connection mode is RF.
The swing type check valve, designed with PN40 RF flange, bolted cover, is made of cast steel 1.0619 and ss316 trim material. The full bore check valve can be manufactured per client's special requests. Quick Detail Type Non Return Valve ( Check Valve) Nominal Size DN 150 NominalPressure PN 40 Construction BB, Swing Type Disc, Exnternal Pin Connection Raised Face Flange Design & Manufacture DIN 3356 End to End EN 558 Connection EN 1092 Test & Inspection EN 12266 Body Material GS-C25 (1.0619) ApplicableTemp -29℃~+425℃ Media W.O.G. Material No Part Name Carbon steel to ASTM Alloy steel to ASTM Stainless steel to ASTM WCB LCB WC6 WC9 C5 CF8 CF8M CF3 CF3M 1 Body A216 WCB A350 LCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 2 Seat Ring A105 A350 LF2 A182 F11 A182 F22 A182 F5 A182 F304 A182 F316 A182 F304L A182 F316L 3 Disc nut A182 F304 A182 F304 A182 F316 A182 F304L A182 F316L 4 Disc washer A182 F304 A182 F304 A182 F316 A182 F304L A182 F316L 5 Disc A216 WCB A350 LCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 6 Hinge A216 WCB A350 LCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 7 Hinge pin A182 F304 A182 F304 A182 F316 A182 F304L A182 F316L 8 Yoke A216 WCB A350 LCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 9 Bonnet nut A194 2H A194 4 A194 7 A194 8 10 Bonnet bolt A193 B7 A193 L7 A193 B16 A193 B8 11 Gasket Stainless Steel Spiral Wound graphite or Stainless Steel Spiral Wound PTFE 12 Cover A216 WCB A350 LCB A217 WC6 A217 WC9 A217 C5 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 13 Hook screw Steel 14 Name Plate Stainless steel or Aluminum 15 Rivet Stainless steel or Aluminum Other Material ( Alloy 20, ANSI 321, Monel Hastelloy, etc)are available on request Our Service A good customer service is as valuable as product itself. In Dervos, we will offer a full range of customer service to make you feel easy when doing business with us. Providing weekly production report When production begins, you will get production report weekly, so that you can have good command of product status and report to your customer at the meantime. Offering warranty of 18 months 18 months warranty period will be offered after shipment, no concern to purchase valve from Dervos. Providing solutions within 3-days for complaints All the complaints will be solved within 3 days, in this case, you can timely reply and solve problems for your customer, to relax them even when complaints happening.
DN600 PN63 Cast Steel Gate Valve is made according to EN1984 standard. The valve body is made of A216 WCB+STL. It has the structural characteristics of Bolted Bonnet, Flexible Wedge, Rising Stem with Yoke. Its connection mode is EN1092-1 B1.
The 20 inch metal seated ball valve is designed for high temperature application or application with solid particulate. The valve has welded body, RF flange connection, bare stem for actuators, belonging to trunnion mounted type. Quick Detail Type Ball Valve Size 20" Pressure ANSI 600 Construction Trunnion Type, One-Piece Body, Fully Welded, Metal to Metal Seat Connection Flanged Operation Bare Stem Body Material Forged Steel ASTM A105 Design Standard API 6D Pressure & Temp ASME B16.34 Face to Face Dimension ASME B16.10 End Connection ASME B16.5 Inspection API 598 Temperature Range -29℃~+200℃ Media Oil, Water, Gas Dimension CLASS 600 DN mm 50 65 80 100 150 200 250 300 350 400 450 500 NPS in 2 2.5 3 4 6 8 10 12 14 16 18 20 L (RF) mm 292 330 356 432 559 660 787 838 889 991 1092 1194 in 11.5 13 14 17 22 26 31 33 35 39 43 47 L1 (BW) mm 292 330 358 432 22 660 787 838 889 991 1092 1194 in 11.5 13 14 17 559 26 31 33 35 39 43 47 L2 (RTJ) mm 295 333 359 435 562 664 791 841 892 994 1095 1200 in 11.63 13.13 14.13 17.13 22.13 26.13 31.13 33.13 35 39.5 43.1 47.3 H mm 153 165 195 213 272 342 495 580 630 725 800 850 in 6.02 6.5 7.68 8.39 10.7 13.5 19.5 22.85 24.8 28.5 31.5 33.5 Do(W) mm 600 850 1250 1300 1500 *350 *350 *600 *600 *800 *800 *800 in 23.62 33.46 49.25 51.22 59 13.8 13.8 23.6 23.6 31.5 31.5 31.5 RF(Kg) 38 56 66 122 217 350 660 820 830 1160 1420 1650 BW(Kg) 31 51 58 117 200 327 605 790 800 1030 1305 1505 *Worm Gear or Electric actuator operated Related Knowledge When to use metal seated ball valve? The seat of a metal seated ball valve is often stellite, stainless steel, or tungsten carbide instead of soft seat material like ptfe, peek, nylon, teflon, and devlon. These metal to metal seat ball valves are especially applicable for: -Media with high temperature -Media with solid particulate for high abrasion -Media with severe condition, like high erosion and corrosion -Media with high viscosity like heavy oil Our Main Product Range Dervos main products include ball valves, butterfly valves, check valves, gate valves, globe valves, and plug valves in different materials, sizes, standards and types as per clients’ requests.
DN25 PN100 ball valve is made according to ISO 17292 standard. The valve body is made of ASTM A105. It has the structural characteristics of floating ball, full bore, anti-fire, anti-static, and anti-flying valve stem. Its connection mode is EN1092-1 D. And it has lever operation mode.
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.
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