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...
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
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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.
Quick Detail Type Globe Valve Designed Size 3/4 Inch Designed Pressure 1500LB Construction Y Type; Bolted Bonnet; Connection Type Socked Weld Operation Handwheel Design Code API602 Connection ANSI B16.11 Test & Inspection API598 Body Material A182 F11+STL Trim Material A276-410+STL Application Water, Oil, Gas Features · Low pressure drop. · Low torque stroking · Quick and easy repair in line. · Tight shutoff. · Stem expansion/contraction thrust unit for high temperature application (optional). · Other sizes available on request. · Live-loading of packing optional. Technical Drawing Dimension Check Witnessing Tests Packing 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.
1/2" 150LB globe valve is made according to API 602 standard. The valve body is made of ASTM A105N+STL. It has the structural characteristics of pass-through type. Its connection mode is RF. And it has hand wheel operation mode.
DN25 PN40 forged steel globe valve is made according to BS 5352 standard. The valve body is made of A182-F316+STL. It has the structural characteristics of bolt cover and straight through type. Its connection mode is EN1092-1 B. And it has hand wheel operation mode.
26" 150LB Butterfly valve is made according to API609 standard. The valve body is made of WCB. It has the structural characteristics of double eccentric, high-performance, bi-directional sealing, fireproof design and anti-corrosion turbine. Its connection mode is lug type. And it has turbine operation mode.
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.
The PN10 DN200 double offset butterfly valve collects durable body and an easy replaceable seat for control services the power, chemical, petrochemical and other fields.
6" 1500LB throttle valve is made according to ASME B16.34 standard. The valve body is made of LF2. It has the structural characteristics of angular, full flow and body cover bolted. Its connection mode is RTJ. And it has hand wheel 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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