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!
These symptoms typically indicate a mismatch in fluid conditions, valve selection, or system configuration. If left unaddressed over prolonged operation, they can accelerate valve wear and pose safety risks. Based on field experience, this article outlines the common causes of valve vibration and noise and provides practical guidance for troubleshooting. 1. Basic Manifestations of Valve Vibration and Noise Valve vibration usually appears as noticeable oscillations of the valve body, stem, or connected piping. Noise may present as humming, whistling, or banging sounds. These phenomena often occur simultaneously and are primarily related to the following factors: ● Abnormal flow velocity or pressure differential ● Unstable internal forces within the valve ● Mismatch between actual operating conditions and valve design 2. Common Causes Analysis 1. Excessive Flow Velocity or Pressure Differential When the fluid passes through the throttling section of a valve at high speed, strong turbulence and pressure fluctuations are likely to occur, causing periodic impact on internal components. This issue is particularly pronounced when using standard globe valves or ball valves under regulating conditions. Typical manifestations include: ● Noise increases as the valve opening decreases ● Vibration intensifies under high-pressure-drop conditions 2. Improper Valve Selection Incorrect valve selection is a common root cause of vibration, such as: ● Using on/off valves for prolonged throttling ● Oversized valve operating at small openings for extended periods ● Insufficient pressure rating or structural rigidity of the valve These conditions can cause unstable movement of the valve plug or ball, resulting in vibration and noise. 3. Loose or Worn Internal Components After long-term operation, the following issues are commonly observed: ● Wear of valve plugs or discs ● Increased clearance between the stem and guiding parts ● Loosened fasteners Non-design clearances amplify fluid impact, leading to persistent noise. If vibration is accompanied by metallic knocking sounds, the condition of internal components should be checked as a priority. 4. Cavitation or Flashing In liquid service, cavitation or flashing occurs when local pressure drops below the saturation vapor pressure. Bubble collapse in high-pressure regions impacts internal components, often accompanied by noise and vibration. Typical signs include: ● Sand- or gravel-like scraping sounds ● Rapid wear of internal components ● Significant pressure fluctuations 5. Insufficient Piping Support or System Resonance Some vibrations are not directly caused by the valve. When upstream or downstream piping lacks adequate support, or when the piping structure resonates near the fluid pulsation frequency, system resonance may occur, amplifying existing vibrations...
2”900LB Pressure Seal Bonnet Gate Valve is made according to ASME B16.34 standard. The valve body is made of A182-F91. It has the structural characteristics of PSB, OS&Y,Solid Wedge . Its connection mode is BW sch 80 ASME B16.25. And it has Handwheel operation mode.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
chinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
A182-F91Method of Operation:
A182-F91
|
Type |
Gate Valve |
|
Size |
2” |
|
Pressure |
900LB |
|
Connection |
BW sch 80 ASME B16.25 |
|
Body Material |
A182-F91 |
|
Design Norm |
ASME B16.34,API602 |
|
BW end size |
ASME/B16.25 |
|
Test & Inspection Code |
API 598 |
|
Temperature |
-29 ~ 649°C |
|
Applicable Medium |
Water, Oil and Gas |
1.Manufactured from F91 alloy steel, offering exceptional high-temperature strength and reliability for 900LB pressure class applications.
2.Pressure seal bonnet gate valve with BW ends and ASME B16.34 compliance ensures secure sealing and long-lasting performance in critical service conditions.
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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.
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.
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 6 inch 150 LB single disc wafer check valve, designed per API 594, has one disc and wafer connection. It will have the best performance under -29 to 350 Celsius degree.
24" 150LB wafer check valve is made according to API 594 standard. The valve body is made of A216 WCB+316. It has the structural characteristics of dual plate and wafer type. Its connection mode is RF.
The 2-piece floating ball valve, made in accordance with API 6A, has a design of reduced bore, fire safe design, anti blowout stem. With the RPTFE seat and PTFE O ring, the 4 inch WCB valve is certificate to serve you.
3" 1500LB strainer is made according to ASME B16.34 standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of plug with DN20 blind flange. Its connection mode is RTJ.
2 1/2" 600LB Forged Steel Gate Valve is made according to API 602 standard. The valve body is made of A105. It has the structural characteristics of Bolted Bonnet, Rising Stem, Solid Wedge, Renewable Seat, Full Bore. Its connection mode is BW. And it has hand wheel operation mode.
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.
1/2" PN160 forged steel globe valve is made according to API 602 standard. The valve body is made of ASTM A105N+STL. It has the structural characteristics of plug cover and plug valve disc. Its connection mode is FNPT. And it has handwheel operation mode.
1" 800LB forged steel globe valve is made according to API 602 standard. The valve body is made of A105N. It has the structural characteristics of bolt cover. Its connection mode is SW. And it has hand wheel operation mode.
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