Butterfly valves are widely used in industrial piping systems due to their compact structure, lightweight design, and quick operation. They are commonly applied in water treatment, chemical, power, oil, and gas industries. However, when dealing with industrial standards across different countries and regions, selecting a butterfly valve that meets the relevant specifications is crucial. This article provides a detailed analysis of butterfly valve design and selection requirements based on three key standards: API 609, ISO 5752, and GB/T 12238. 1. API 609 — American Petroleum Institute Standard API 609 is the American Petroleum Institute (API) standard for metal-seated butterfly valves, primarily used in the oil, gas, and chemical industries. The standard defines valve structure, materials, dimensions, and pressure ratings to ensure reliable performance under high temperature, high pressure, and corrosive media conditions. Key points include: ● Pressure Ratings: Covers Class 150 to 1500, accommodating various service conditions. ● Body and Disc Design: Metal-to-metal sealing requires precise alignment between disc and seat to prevent leakage under high temperature or high pressure. ● Testing and Inspection: Includes shell tests, seat leakage tests, and operational performance checks to ensure valve safety and reliability. For high-temperature steam or high-pressure oil and gas pipelines, selecting a butterfly valve compliant with API 609 can significantly reduce leakage risk and extend equipment lifespan. 2. ISO 5752 — International Standard Organization Standard ISO 5752 is the International Organization for Standardization (ISO) standard that specifies end dimensions and flange connection sizes for valves. It defines the face-to-face dimensions, flange sizes, and connection methods for butterfly valves, providing a consistent interface specification for industrial users worldwide. Key points include: ● Face-to-Face Dimensions: Specifies valve lengths for different nominal diameters to ensure compatibility with piping systems. ● Flange Dimensions: Ensures valves match international standard pipe fittings, such as ANSI or DIN flanges. ● Interchangeability: Butterfly valves designed according to ISO 5752 can be replaced or serviced globally without redesigning the pipeline interface. ISO 5752 is particularly suitable for multinational engineering projects, ensuring the universality of butterfly valves across different plants and systems. 3. JB/T8527 — Chinese National Standard JB/T8527 is the Chinese national standard specifying the dimensions, structure, and testing requirements for metal hard-seal butterfly valves. It is widely applied in domestic industrial projects such as water conservancy, power, and petrochemical industries, serving as an important reference for procurement and acceptance. Key ...
Check valves are often considered the most “quiet” yet essential components in a piping system. Their primary function is to prevent backflow and safeguard pumps, compressors, and the overall stability of the system. However, in real-world applications, poor sealing—commonly referred to as “leakage”—is one of the most frequent and frustrating issues encountered in check valve operation. When a check valve fails to seal properly, it can reduce system efficiency, trigger pressure fluctuations, cause water hammer, and even damage critical equipment. This article breaks down the technical causes behind check valve leakage and offers practical diagnostic and corrective measures to help you quickly identify and resolve sealing problems, even under challenging operating. 1. Why Does a Check Valve Fail to Close Properly? Common Causes Explained 1. Presence of Particles or Solid Impurities in the Medium Solid particles can become trapped between the disc and the seat, preventing full contact and causing slight or even noticeable leakage. Typical signs include: ● Significant leakage at small opening positions ● Leakage decreases after cleaning 2. Disc Wear or Seat Damage Frequent cycling, corrosive media, or high-velocity flow can wear the sealing surfaces, resulting in scratches, pits, or deformation. This issue is especially common in high-temperature steam systems. 3. Incorrect Installation Direction or Insufficient Tilt Angle Although it may sound like a basic mistake, incorrect installation still occurs on many job sites. Since check valves rely heavily on gravity and flow direction, improper installation prevents the disc from returning to its closed position smoothly. 4. Flow Velocity Too Low to Create Adequate Differential Pressure A check valve opens through fluid flow. When the flow rate is too low, the disc may flutter or fail to close completely, leading to leakage. Common scenarios include: ● Insufficient straight-pipe length ● Frequent pump start/stop ● Poorly designed low-flow systems 5. Disc Sticking or Hinge Mechanism Not Operating Smoothly In swing check valves, rust, corrosion, or lack of lubrication at the hinge pin or disc connection may cause sticking, preventing full closure. 6. Thermal Deformation of Sealing Surfaces Due to Temperature Fluctuations In high-temperature conditions such as steam service, thermal expansion and contraction can slightly deform sealing surfaces, resulting in an imperfect seal. 2. How to Quickly Determine If a Check Valve Is Not Closing Properly? 1. Abnormal Pressure Gauge Readings If the inlet pressure remains stable while the outlet pressure gradually rises, backflow caused by check-valve leakage is the most likely reason. 2. Pipe Vibration or Light Knocking Sounds This indicates that the disc is oscillating at high frequency, often due to insufficient flow velocity or a loose dis...
Recently, representatives from Dervos Valve visited long-term industrial valve partners in Norway, Italy, Germany, and Spain. The multi-day trip focused on understanding customers’ current project requirements and discussing future procurement plans and technical specifications in greater depth. In Norway, our team was invited to visit the customer’s equipment installation workshop and valve application site. Through direct discussions with the engineering and procurement teams, we gained a clear understanding of their concerns regarding high-pressure applications, material selection, and delivery schedules. The customer noted, “Dervos has an excellent grasp of our project needs. Your quick response and professional recommendations give us great confidence.” This feedback reflects not only trust in our product quality but also strong recognition of our service capabilities. The team then traveled to Italy for technical discussions with our local partners and visited their valve assembly and testing facilities. Our representatives introduced Dervos’s manufacturing capabilities, quality inspection processes, and ongoing product enhancements across ball valves, gate valves, butterfly valves, and check valves. The Italian customer remarked, “The solutions you presented are highly practical and will significantly improve the reliability of our projects.” Such positive feedback further strengthened the confidence in our partnership. Through this trip, Dervos gained deeper insights into the European market’s expectations regarding valve performance, quality control, and delivery reliability. We will continue to refine our products and services based on customer feedback, ensuring that every partner receives a reliable and fully tailored one-stop valve solution. Looking ahead, Dervos Valve will remain committed to our service philosophy of listening to customers, responding quickly, and delivering real value. With higher product standards and more professional technical support, we aim to strengthen and advance our cooperation with customers around the world.
The knife gate is a bi-directional lug type valve designed according to MSS-SP-81 and for industrial service applications. The design of the body and seat assures non-clogging shut off on suspended solids in industries.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
ChinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
2205Method of Operation:
HandwheelQuick Detail
|
Type |
KnifeGate Valve |
|
Size |
6'' |
|
Design Pressure |
150LB |
|
Construction |
Knife Type Gate Valve |
|
Connection Type |
Lug Type， RF |
|
Operation Type |
Hand wheel |
|
Body Material |
2205 |
|
Seat Material |
EPDM |
|
Design Code |
MSS SP-81 |
|
Flange Dimensions |
ASME B16.5 |
|
Temp. Range： |
-29~.+120℃ |
|
Medium |
Water, Oil and Gas |
|
Origin |
China |
Features
All stainless steel design
Standard knife gate valves: NPS 2–24 (DN 50–600)
Bolted bonnet knife gate valves: NPS 4–24 (DN 50–600)
ASME Classes: 1690-4500
0-14ph packing standard
Locking device on standard knife gate valve
Environmentally friendly bi-directional bolted bonnet and standard body styles
Resilient and metal seats
Technical Drawing
Before Manufacturing
Nameplate&Packaging
Reports
For each order, Dervos will provide inspection reports to show you the whole inspection process and results. Plus, we will provide material report to let you know that the material we provide is as per standards.
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 6 inch stainless steel gate valve, designed as per MSS-SP-81, has the lug type connection per Class 150 and electric actuator. Quick Detail Type Knife Gate Valve Size 6'' Design Pressure ANSI 150 Construction Knife Type Gate Valve ConnectionType Lug Type OperationType Electric Actuator Body Material ASTM A351 CF8 TrimMaterial SS304 Design Code MSS SP81 Medium Water, Oil and Gas Origin China Related Knowledge What are knife gate valves used for? Knife gate valves are originally designed for paper industry. The knife gate valve is especially applicable for heavy liquids with solid particulates, like slurry liquid, that are most corrosive, erosive and abrasive. Compared to wedge gate valve, the knife gate valve has a shorter end to end dimension and lighter weight. Plus, the knife valve has a more sharpened disc to cut through slurry and viscous medium. Both wedge gate valve and knife gate valve can only be used for on-off function not for regulating the flow. Dervos Customer Service With Dervos customer service, you will not have any concern before, during and after buying valves. Pre-sales We will reply on time and also provide technical support upon your request. Order We will check the production details with factory and customers. Sales confirmation will also be sent. During production, we will also send weekly report to let you know the order status. Before shipment, delivery note will be sent to let you know the situation. 18 Month warranty Dervos is always responsible for their products. We will provide 18 months warranty to let our customers without concern.
The stainless steel knife gate valve is designed with DN800 PN6 flange end and gearbox operation. The soft seated knife gate valve has a unidirectional sealing. Quick Detail Type Gate Valve Size DN800 Design Pressure PN6 Construction Unidirectional, Soft Seated ConnectionType Flange End OperationType Gearbox Operated Body Material CF8M DiscMaterial SS316L StemMaterial SS316 SeatMaterial PTFE Design Code MSS SP81 Medium Water, Oil and Gas Origin China Dimension Checking Pressure Tesing
The DN150 PN10 unidirectional knife gate valve features a single piece, stainless steel body design provides tested performance in applications ranging from general purpose to severe media.
The lug type knife gate valve is designed per MSS-SP-81.Made by stainless steel CF8, the 4 inch gate valve has 150 LB flange connection and handwheel operation.
2" 150LB knife gate valve is made according to MFS standard. The valve body is made of ASTM A351 CF8. It has the structural characteristics of bilateral sealing and with flow deflector. Its connection mode is lug. And it has hand wheel operation mode.
1/2" 300LB gate valve is made according to API602 & ASME B16.34 standard. The valve body is made of A105N. It has the structural characteristics of BB, OS&Y, rigid wedge, NACE MR0175, corrosion allowance 3mm and leakage level ISO5208A. Its connection mode is RF overall. And it has hand wheel operation mode.
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.
2" 600LB inverted pressure balanced lubricated plug valve is made according to API 6D standard. The valve body is made of A216 WCB. It has the structural characteristics of inverted pressure balance type, oil sealed. Its connection mode is RF. And it has Lever operation mode.
Dervos bellow seal globe valve is designed as per EN13709 with face to face dimesnsion per EN558. The special designed bellow seal make sure zero leakage from stem. Quick Detail Type Globe Valve Norminal Size DN 65 NorminalPressure PN 40 Construction Bolted Bonnet, Rising Stem, Bellow Sealed ConnectionType RF Flange Operation Handwheel Design Code EN13709 Face to Face EN 558 Connection EN1092 Test & Inspection EN12266 Body Material Carbon Steel 1.0619 Bellow Material SS304, SS316, SS316L and etc ApplicableTemp -29℃~+420℃ Application Water, Oil, Gas Structure Feature 1. Standard design of double-wall bellow seal 2. Heat-dissipating bonnet design; 3. With lubricant storage device; 4, With design of circlip to fix stem nut; 5. Reasonable product structure, reliable sealing performance and good appearance; 6. The sealing surface is welded with Co-based hard alloy, which has good wear resistance, corrosion resistance, anti-friction performance and long service life; 7. Stem has nitriding treatment with good corrosion resistance and anti-friction performance; 8. With position indicator for stem movement;
Quick Detail Type Globe Valve Size DN15 DesignPressure PN160 Construction Tee Pattern Connection Socket Welded Design & Manufacture BS5352 Socket Weld ANSI B16.11 Test & Inspection EN12266 Body Material A182 F5+STL Trim Material A276 410; STL Media WOG Description --Tee Pattern is the most common type of globe valve with a z shaped diaphragm. --The seat is oriented horizontally allowing the stem and disk to travel perpendicular to the horizontal line. This alsocontribute to low flow coefficient and higher pressure drop. Features --Good shutoff capability --Moderate to good throttling capability --Shorter stroke (compared to a gate valve) --Available in tee,WYE, and angle patterns, each offering unique capabilities --Easy to machine or resurface the seats --With disc not attached to the stem, valve can be used as a stop-check valve Technical Drawing Dimension Check Witnessing Tests Nameplate & Packing FAQ 1.Can the ordersalways be delivered on time? Our purchasingteam follows up very closely with each order tomake sure on-time delivery for most of orders. In 2018,more than 90% orders were delivered on time, and we are dedicated to doing better. 2.What’s the normal delivery lead time? For normal material, usually the delivery time is about 35~40 days, and for forged material, the delivery canevenbe shortened to 20~25 days. We believe the short lead time can make our offer more competitive and help you secure more orders. Do you have different price levels for us? With our numerous suppliers, different price levels are available with us, so we are able to help you win more customer from different markets requesting for high, medium and low prices. About Dervos Xiamen Dervos Valves Industry Co.,Ltd (stock code 861601), founded in June 2008, is a one-stop industrial valves supplier integrated of R&D, manufacture, resource integration, and trade service. For 12 years, Dervos has been committed to finding solutions for industrial needs and providing professional service for both general and specialized valves.
8”300LB Cast Steel Y Type Strainer is made according to ASME B16.34 standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of Y Type. Its connection mode is RF.
The cast steel lift non return check valve is designed with piston type disc, bolted bonnet, and PN16 RF flange. The spring loaded check valve conforms to DIN 3356. Quick Detail Type Check Valve ( Non-return Valve) Nominal Diameter DN 150 NominalPressure PN 16 Construction Lift Type / Piston Type, Bolted Bonnet Connection Flanged Connection Design & Manufacture DIN 3356 End to End EN 558 Connection EN 1092 Test & Inspection EN 12266 Body Material Carbon Steel GS C25 Media W.O.G. Product Range Body material: CS, SS, Alloy Steel, CI, Bronze, Brass Size Range: 2”~12” (DN50~DN300) End Type: Butt Weld, Socket Weld, Flanged, Screwed Pressure Range: 150lbs~2500lbs (PN16~PN420) Temperature Range: -46℃~ +425℃ Related Knowledge What is a piston check valve? Usually, we have swing type check valve and lift type check valve. A piston check valve and ball check valve both belong to lift type check valve. In a lot of cases, a piston check valve use spring to retain the disc in closed position. The structure of a piston check valve is very similar to the globe valve just without manual operation. Due to its piston type disc and superior leak tight characteristic, the piston check valves are suitable for small size and high pressure conditions.
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