In any efficient and reliable lubrication system, oil cleanliness is a core factor affecting equipment lifespan and operational efficiency. Strainers, as the front-line filtration devices in lubrication systems, play a critical role in pre-filtration. However, engineers and operators often raise the following questions: Can oil pass through strainers smoothly? What exactly is the function of a strainer? How does it differ from subsequent fine filters? This article systematically explains the role of strainers in lubrication systems, covering their working principles, pre-filtration objectives, and practical applications across different systems. 1. Can Oil Pass Through a Strainer? Answer: Yes, but with limitations. (1) Strainer Structure Allows Oil Flow A strainer is fundamentally a low-precision filter made of stainless steel mesh or perforated metal plates. It features uniform pores, typically sized between 80–500 μm (micrometers), allowing most clean oil to flow through unimpeded. (2) Contaminants Are Blocked Particles such as metal shavings, seal fragments, and carbon deposits in the oil are intercepted by the strainer, preventing them from entering the oil pump or other critical components. (3) Oil Temperature and Viscosity Affect Flow Efficiency Low temperatures or high-viscosity oil may reduce flow rates or even cause blockages. This is one reason for low oil pressure during system startup. 2. Objectives and Significance of Pre-Filtration (1) Protecting the Oil Pump Internal pump components (gears, impellers, or plungers) are highly sensitive to solid particles. Pre-filtration prevents particles from entering the pump, avoiding premature wear or seizure. (2) Reducing Load on Primary Filters By intercepting large contaminants, strainers allow primary filters (e.g., oil filter cartridges) to focus on finer impurities, extending their service life and maintaining stable system flow. (3) Lowering System Failure Rates Pre-filtration reduces risks such as pump failure, orifice blockages, and lubrication breakdown caused by foreign particles, enhancing overall system reliability. 3. Typical Applications of Pre-Filtration Devices Application System Strainer Installation Position Strainer Type Internal Combustion Engine Lubrication Oil sump → Pump inlet Coarse metal strainer Hydraulic Systems Tank outlet → Pump suction port Suction strainer or basket strainer Turbine Lubrication Systems Pump inlet Dual-chamber switchable suction strainer Transmission/Clutch Systems Oil sump → Circulation pump inlet Perforated plate + magnetic strainer 4. Design and Usage Considerations for Strainers (1) Pore Size Selection Must Align with System Precision Requirements 80–100 μm: Typical for engine oil systems. 150–300 μm: Used in hydraulic equipment. >400 μm: Suitable for low-pressure or open-loop systems. (2...
Ball valves, with their simple structure, easy operation, and excellent sealing performance, have become widely used control components in both industrial and residential sectors. Particularly in water supply systems, an increasing number of engineers and installers are choosing ball valves as the primary fluid control device. But are ball valves truly suitable for water systems? How should one properly select and install them to ensure long-term stable operation? This article provides a comprehensive overview from the perspectives of structural principles, performance characteristics, and application recommendations. 1. Advantages of Ball Valves in Water Systems (1) Quick Opening and Closing Ball valves can complete the opening and closing operation with a simple 90° rotation, making them easy to operate and highly responsive—ideal for emergency situations or water systems that require frequent switching. (2) Excellent Sealing Performance High-quality ball valves are equipped with PTFE or reinforced sealing materials, enabling zero leakage. They are particularly suitable for water supply systems in residential buildings, commercial complexes, and industrial facilities where sealing performance is critical. (3) Compact Structure and Space-Saving Compared to gate valves or globe valves, ball valves occupy less space and offer flexible installation, making them ideal for water modules with high equipment integration. (4) Strong Corrosion Resistance Ball valves made of stainless steel, brass, or plastic materials (such as UPVC) offer excellent corrosion resistance, capable of handling various water qualities (soft water, hard water, reclaimed water) and different additives. 2. Application Scenarios Analysis Ball valves are suitable for the following types of water systems: (1) Domestic Water Systems: Such as internal building water supply, point-of-use control for sanitary fixtures, and garden irrigation systems. (2) Industrial Water Systems: Such as cooling water circulation systems, boiler feedwater systems, and water supply for cleaning equipment. (3) Water Treatment Systems: Including reverse osmosis pretreatment, greywater recycling, and wastewater transfer processes. (4) Special Applications: High-pressure hot water systems or cleaning water containing chemical additives. However, caution should be exercised in the following scenarios: (1) High-Frequency Modulation Conditions Standard ball valves are not suitable for precise flow regulation. It is recommended to use V-port ball valves or control-type electric ball valves. (2) Water Containing Sand, Gravel, or High Levels of Suspended Solids A Y-strainer should be installed to prevent particle blockage or damage to the sealing surfaces. (3) High-Temperature Hot Water Systems High-temperature ball valves with metal sealing structures should be selected to prevent seal aging and deformation. 3. Key Selection Criteria To ensure stable operation o...
Ball valves are widely used industrial flow control components, commonly found in applications such as water treatment, oil and gas, chemical processing, HVAC systems, and the food and pharmaceutical industries. Thanks to their compact structure, quick shut-off capability, and excellent sealing performance, ball valves play a critical role in various fluid systems. However, even the most reliable ball valve can encounter failures after prolonged operation. When a ball valve fails, it can compromise the stability of the entire system and, in severe cases, lead to media leakage or even safety incidents. Therefore, understanding the root causes of ball valve failure and implementing effective preventive measures is essential for engineers and maintenance personnel. 1. Seal Failure Cause: Seal failure in ball valves is often caused by seat wear, debris accumulation, or aging of sealing materials. This issue is especially common in high-temperature, high-pressure, or corrosive media environments. Prevention Tips: To extend the service life of the seal, choose ball valves with PTFE or metal seats that are compatible with the process media. Regularly clean the seat area and establish a replacement schedule based on the operating conditions. 2. Corrosion or Scratches on the Ball Surface Cause: When a ball valve is used with media containing acids, alkalis, high salt content, or abrasive particles, improper material selection can lead to corrosion, pitting, or surface scratches. These issues reduce sealing performance and affect smooth operation. Prevention Tips: Select stainless steel ball valves (such as 304 or 316 grades) or special alloy ball valves based on the specific media characteristics. Additionally, install a strainer or filter to minimize solid particle intrusion and protect the valve internals. 3. Stem Breakage or Seizure Cause: The valve stem, which transmits torque to the ball, may experience metal fatigue and fracture under frequent operation or excessive torque. Seizure can also occur due to bearing wear or lack of lubrication. In some low-quality ball valves, insufficient structural design margin further increases the risk of stem failure. Prevention Tips: Use ball valves with blow-out proof stem designs to enhance operational safety. Ensure that operating torque stays within the valve’s rated limits, and apply lubricant regularly to reduce friction and wear, extending service life. 4. Improper Installation or Operation Cause: Human errors such as incorrect installation direction, loose flange connections, or frequent forceful operation are major contributors to early ball valve failure. In the case of electric or pneumatic ball valves, signal control errors can also lead to misoperation or valve jamming. Prevention Tips: Always follow the manufacturer’s installation guidelines, ensure proper alignment and secure flange connections. Install limit switches and torque protection devices to safeguard...
The refinery of MOL, located in Hungary, requires regular ball valve and check valve replacements to maintain optimal performance. As a trusted check and ball valve supplier of MOL, DERVOS continues to provide ball valves for their operations.
In this project, DERVOS supplied a batch of high-performance ball valves and check valves for fluid control in oil and gas applications. They required various types and specifications of ball and check to meet the operational and sealing requirements of different pipeline systems.
Trunnion Mounted Ball Valves (112 units)
· Size: DN80-DN400
· Pressure: PN16-PN63
· Features: Full flow ball valve design, DBB double block and bleed structure, PMSS seal (primary metal + secondary soft seal), anti-blowout stem, IP68 waterproof turbine operation.
Floating Ball Valves (71 units)
· Size: DN20-DN25
· Pressure: PN25-PN63
· Features: Floating ball design, handle operation, suitable for small and medium-sized pipelines.
Swing Check Valve (9 units)
· Size: DN50-DN300
· Pressure: PN25-PN63
· Features: Swing type, simple structure and low flow resistance, suitable for large flow and low-velocity conditions.
In this project, 4 units fixed ball valves were customized with 2-meter extended valve stems and turbines oriented toward the operating platform.
This design ensures operators can safely and efficiently operate and maintain the valves from a distance, fully addressing the site’s needs.
The custom solution showcases DERVOS’s flexibility in meeting customer requirements and engineering expertise.
The end user, MOL, highly recognized the quality and performance of the valves, noting the excellent painting for its durability. They praised DERVOS products as reliable, safe, and fully meeting the project’s requirements.
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In 2017, DERVOS contributed to an innovative environmental initiative led by ECOFUEL, an emerging canadian player in clean technology. This groundbreaking project aimed to produce sustainable diesel from solid waste, setting a precedent in green energy solutions. DERVOS is proud to have provided 136 sets of premium valves to support this pioneering effort.
The DN80 PN16 cast iron gate valve has face to face dimension as per DIN3202 F4 or DIN3202 F5. This GG25 gate valve is designed with resilient seat, non rising stem, bb, RF flange, suitable for water treatment application. Quick Detail Type Gate Valve Nominal Diameter DN 80 Nominal Pressure PN 16 ConstructionType Non-rising stem, Bolted Bonnet, Resilient Seat ConnectionType Flanged OperationType Handwheel Operation Body Material Cast Iron GG25 TrimMaterial Cast Iron Wedge, SS420 Stem, EPDM Seat Design Code DIN 3352 End to End Code DIN 3202 Flange Dimesion DIN 2501 Medium Water Origin China Design Feature 1.Resilient seat for good sealing performance 2.Low flow resistance and small pressure drop 3.Non-rising stem for installation space is limited 4.No limitation for flow direction of medium 5.Epoxy painting available for internal and external part of the valve for anti corrosive function Company Brief Introduction Specializing in valve industry over 10 years, Dervos becomes the leading vendor of gate, globe, check, ball, butterfly, plug valves and strainers. We serve oil and gas user such as LUKOIL, MOL, YPF with local partners. Dervos show its advantages in: 1. Our partnerships with tens of stable suppliers allow us to provide customers with a wide range of high-quality products at a competitive price. 2. Each order is under strict quality control with inspection reports before delivery. 3. We value delivery time as much as our customers do. With the powerful purchasing system, we follow each order closely to secure on-time delivery. 4. One-stop solutions will be offered in a timely manner
The 6 inch sleeved plug valve features in non lubricated design and soft seat. The full port plug valve is made of carbon steel body and PTFE seat as per API 6D, with Class 150 flange connection. Quick Detail Type Plug Valve Size 6'' Design Pressure 150LB Construction Self-Lubricated Type, Sleeved Type, Soft Seat Connection Type RF Flange Operation Gearbox Operation Design Code API 599 Face to Face ASME B16.10 End Connection ASME B16.5 Pressure & Temp ASME B16.34 Test & Inspection API 598 Body Material A216 WCB Temperature Range -29℃~+425℃ Application Water, Oil, Gas Material & Dimension No Part Name Carbon steel to ASTM Stainless steel to ASTM WCB LCB CF8 CF8M CF3 CF3M 1 Body A216 WCB A350 LCB A351 CF8 A351 CF8M A351 CF3 A351 CF3M 2 Bonnet A216 WCB A350 LCB A351 CF8 A351 CF8M A351 CF3 A351 CF3M 3 Plug A105 A182 F304 A351 CF8 A351 CF8M A351 CF3 A351 CF3M 4 Stem A182 F6 A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 5 Seat Ring PTFE 6 Gasket PTFE or Stainless Steel and Graphite 7 Stem Seat PTFE PTFE PTFE PTFE PTFE PTFE 8 Small spring 17-17PH 9 Small ball A182 F304 or A182 F316 10 Gland A182 F6 A182 F6 A182 F304 A182 F316 A182 F304L A182 F316L 11 Gland Flange A216 WCB A350 LCB A351 CF8 A351 CF8M A351 CF3 A351 CF3M 12 Stem packing PTFE or Graphite 13 Bonnet bolt A193 B7 or A320 L7 or A320 B8 or A193 B8M 14 Bonnet nut A194 2H or A194 4 or A194 8 Class 150 DN mm 15 20 25 40 50 65 80 100 150 200 250 300 NPS in 1/2 3/4 1 1 1/2 2 2 1/2 3 4 6 8 10 12 L(RF) mm 108 117 127 165 178 191 203 229 394 457 533 610 in 4.25 4.6 5 6.5 7 7.5 8 9 15.5 18 21 24 L1(BW) mm 140 152 165 190 216 241 283 305 457 521 559 635 in 5.5 6 6.5 7.48 8.5 9.5 11.13 12 18 20.5 22 25 L2(RTJ) mm 119 129.7 139.7 178 191 203 216 241 406 470 546 622 in 4.69 5.11 5.5 6.9 7.5 8 8.5 905 16 18.5 21.5 24.5 H mm 59 63 75 92 153 165 195 213 272 342 495 580 in 2.3 2.5 2.95 3.74 6.02 6.5 7.68 8.39 10.7 13.5 19.5 22.85 D(W) mm 130 130 160 230 400 400 600 850 1100 1500 350* 350* in 5.1 5.1 6.3 9 15.74 15.74 23.62 33.46 43.3 59 13.8 13.8 Weight (Kg) RF 2.3 3 4.5 7 15 20 25 40 97 160 240 390 BW 2.0 2.5 3.8 5.8 12 17 21 36 92.8 154 227 365
DN20 800LB PN130 Forged Steel A105 SW Connection Way BB OS&Y Handwheel Operation Gate Valve Body and Bonnet A105 API600 Trim 8 Seat 410+STL Wedge 420 Stem 410 Gasket 304+Graphite Design and Manufacture API602 Face to Face ANSI B16.11 Welded end Dimensions API 602 Test and Inspection API 508. Quick Detail Type Gate Valve Size DN20 Pressure 800LB Construction BB,OS&Y Connection SW Operation Mode Handwheel Body Material A105 Cover A105 Design & Manufacture API 602 End Connection API 602 Inspection API 598 Temperature Range -29℃~+425℃ Medium Oil, Water, Gas
2" 300LB dual plate wafer check valve is made according to API 594 standard. The valve body is made of A182 F316. It has the structural characteristics of double disc. Its connection mode is RF.
DN125*DN80 PN25 ball valve is made according to ISO 17292 standard. The valve body is made of ASTM A105. It has the structural characteristics of fixed ball and insulation jacket. Its connection mode is EN1092-1 B. And it has gear operation mode.
API 6D ball valve is designed with an extended stem for special use, like underground ball valve or low temperature application. The length of the extended stem can be customized as per client's request. Quick Detail Type Ball Valve Size 2 Inch Pressure Class 600 Construction Split Body, Side Entry, Floating Type, Firesafe Design, Antistatic System, Anti-Blowout Stem, Extended Bonnet Connection RF Flange Operation Mode Lever Body Material A105N Trim Material SS304 Ball and Stem, RPTFE Seat 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 QC Process in Dervos Casting inspection： We can find out the raw material’s problem, such as shoddy casting, unqualified wall thickness, chemical composition and so on, which ensure that you will not be cheated. Machining Inspection: -Ensure machining accuracy -Find out machining mistake as early as possible, to win more time for repairing, remaking Final Inspection: -Final inspection activities include document and QC record review, visual examination, dimension check, pressure test, painting and packing check -Save time and cost: you don’t need to come and inspect in person and all the documents could be provided as proof. Inspection report will be provided free of charge including: -EN 10204 3.1 Mill Test Certificate -Inspection Report, showing the whole inspection process
DN450 PN16 ductile iron 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 valve, and structural length of 330mm. Its connection mode is RF. And it has hand wheel operation mode.
4" 600LB ball valve is made according to API 6D standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of split type, fixed ball, full bore, fireproof, anti-static, anti-flying valve stem. Its connection mode is RF.
4" 600LB check valve is made according to API 6D standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of swing type, external pin. Its connection mode is RF.
DN800 PN25 double eccentric butterfly valve is made according to EN593 standard. The valve body is made of ASTM A216 WCB + Internal Epoxy Coating. It has the structural characteristics of double eccentricity, unidirectional and structural length of 200mm. Its connection mode is double flange RF EN1092-1.
The 1.5 inch 800LB bellow seal globe valve is designed with outside screw and yoke, handwheel operation, sw end. The reduced port globe valve is has forged steel A105N body. Design Feature 1.Outside screw and yoke 2.Rising stem 3.Bolted bonnet design 4.Bellow seal packing for reliable stem sealing 5.Reduced bore design 6.Handwheel Operated Quick Detail Type Globe Valve Size 1.5'' Design Pressure Class 800 Structure BB, OS&Y, Reduced Port, Bellow Seal Packing Connection Type Socket Weld Operation Handwheel Design Code API 602 End to End ASME B16.10 Connection End ASME B16.11 Pressure & Temperature ASME B16.34 Test & Inspection Standard API 598 Body Material Forged Steel ASTM A105 Trim Material Trim 8 Applicable Temperature -29℃~+425℃ Application W.O.G Origin China Related Knowledge What is a bellw seal valve? For bellow seal globe valves, the lower end bellows is welded on the valve stem to prevent the process fluid from eroding the valve stem. The other end is placed between the valve body and the valve cover to form a static seal. The double seal design ensure that if bellow seal pakcing fails, the stem packing will also function. The bellow seal globe valves are applicable for media like steam, flammable, explosive, heat transfer oil, high purity, and toxic media etc. Special Tests Besides general tests we will do (hydraulic and air test), we could also do tensile strength test, metallographic test, fugitive emission test, and NDE test (UT,RT,PT,MT) upon customers’ specific requests.
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