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When Should a Check Valve Not Be Used?
When Should a Check Valve Not Be Used?
2025-09-26

Have you ever encountered repeated fluid shocks, frequent valve cycling, or excessive noise in your pipeline system? If a check valve is not selected properly, issues such as leakage, valve damage, or fluid hammer can occur. While check valves are effective at preventing backflow, they are not suitable for all operating conditions. The following cases require special attention:   High-frequency opening and closing conditions Check valves rely on the disc or flap to close automatically. If the medium in the pipeline flows frequently or the valve cycles too often, impact, water hammer, or vibration may occur, shortening the valve’s service life. In such cases, consider using spring-loaded or damped check valves, or even other valve types better suited to the application.   High-viscosity fluids or media with solid particles Thick fluids or those containing solids can prevent the valve disc from closing fully, increasing the risk of leakage. For slurries, mud, or liquids with a high concentration of particles, specialized valves or additional filtration equipment should be used instead.   High-pressure systems In high-pressure applications, the valve disc is subject to strong impacts and repeated collisions, which can cause wear on the sealing surfaces or structural damage. For such environments, more robust backflow prevention solutions should be considered.   Systems Sensitive to Pressure or Flow Variations When a check valve closes, it may cause pressure loss or flow fluctuations. If the system is highly sensitive to such variations, careful evaluation of the valve type and installation location is required to avoid negative impacts on overall pipeline performance.   Conclusion A check valve is an essential device for preventing backflow, but it should be used with caution in certain operating conditions such as high-frequency cycling, high-viscosity fluids, high-pressure systems, or applications sensitive to flow variations. By properly assessing the pipeline operating conditions and fluid characteristics, you can ensure the check valve performs at its best, extends service life, and reduces maintenance costs.

What Are the Types of Disc Designs in Globe Valves?
What Are the Types of Disc Designs in Globe Valves?
2025-09-18

Have you ever faced the challenge of selecting the right globe valve disc during pipeline system design or operation? When using a globe valve to control fluid flow, the disc type directly affects sealing performance, flow regulation, and suitability for specific conditions. Understanding the types of discs and their applications can help you make faster, more accurate selections and improve overall system efficiency.   Flat / Standard Disc   Features: The disc has a flat sealing surface, simple structure, and relatively low manufacturing cost. Applications: Commonly used for water, steam, air, and other low-viscosity media. Suitable for medium to low-pressure systems.   Pros & Cons: Provides basic and reliable shutoff, but sealing reliability is moderate. Under long-term high pressure or high temperature, the sealing surface may wear more quickly.   Conical / Tapered Disc   Features: The disc is conical in shape, matching the sealing surface of the valve seat with a smaller contact area. Applications: Ideal for high-pressure conditions or systems requiring precise shutoff, such as steam and oil pipelines. Pros & Cons: Offers excellent sealing performance, but requires greater operating torque for opening and closing.     Plug / Concave Disc   Features: The disc surface is slightly convex, forming point contact with the valve seat, offering high sealing precision. Applications: Suitable for gases, liquids, and some corrosive media, allowing effective flow regulation.   Pros & Cons: Manufacturing cost is higher, but sealing performance and wear resistance are superior to flat discs.   Double Disc   Features: A large disc contains a smaller inner disc. Applications: Commonly used in high-pressure, large-diameter valves. It helps balance pressure and extend valve service life. Pros & Cons: Structurally more complex and more expensive, but ideal for high-pressure, large-diameter applications.     Conclusion     Globe valve discs come in a variety of types, each with unique advantages and suitable working conditions. When selecting a disc, consider the medium type, pressure, temperature, and flow requirements. Choosing the correct disc ensures reliable system sealing, extends valve life, and reduces maintenance costs.

Which Inspection Reports Must Be Requested from the Supplier When Purchasing Gate Valves
Which Inspection Reports Must Be Requested from the Supplier When Purchasing Gate Valves
2025-09-12

If you have ever experienced project delays due to valve quality issues, or are in the process of selecting qualified valve suppliers for an upcoming industrial project, then understanding the essential inspection reports required when purchasing gate valves becomes critically important. As a key control component in piping systems, the quality of a valve directly affects the safety and reliability of equipment operation. Therefore, when purchasing gate valves, buyers should not only focus on price and delivery time but also ensure that the supplier can provide complete inspection reports.   Mandatory Inspection Reports   ● Material Test Report (MTR) Purpose: To verify that the main components of the valve, such as the body, bonnet, and stem, meet the specified material standards (e.g., ASTM, DIN, EN). Importance: Prevents valve failure under corrosive or high-pressure conditions due to substandard materials.   ● Pressure Test Report Hydrostatic Test: Checks the valve’s strength under the specified pressure. Air Tightness Test: Ensures the valve does not leak at operating pressure. Importance: Confirms that the valve meets the required design pressure rating.   ● Dimension Inspection Report Content: Verifies whether valve structural length, flange dimensions, wall thickness, etc., comply with design and standards (ANSI, EN, GB). Importance: Ensures proper alignment with the piping system and prevents installation deviations.   ● Non-Destructive Test (NDT) Report Methods: Includes Ultrasonic Testing (UT), Radiographic Testing (RT), Magnetic Particle Testing (MT), and Penetrant Testing (PT). Importance: Verifies that castings or welds are free from internal defects, enhancing the valve’s long-term operational reliability.   ● Coating & Painting Test Report Content: Checks paint thickness, adhesion, hardness, salt spray resistance, etc. Importance: Ensures the valve has strong corrosion resistance for outdoor, marine, or chemical environments.   ● Final Inspection Report Content: Includes comprehensive records of appearance, operational performance, markings, packaging, and other inspection items. Importance: Demonstrates that the valve has undergone strict quality control before delivery.   Conclusion   When purchasing gate valves, requiring suppliers to provide complete inspection reports is not only a verification of product quality but also a guarantee of overall project safety and reliability. By reviewing these reports, customers can reduce operational risks, lower maintenance costs, and extend the service life of their equipment.   Q&A   Q1: Why is a Material Test Report (MTR) mandatory when purchasing gate valves? A1: Material determines the valve’s pressure resistance, corrosion resistance, and service life. Different operating conditions require specific materials, so an MTR is necessary to verify compliance.   Q2: Is Non-Destructive Testing (NDT) require...

150LB high performance double offset butterfly valve WAFER
加载中...

150LB high performance double offset butterfly valve WAFER

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.

  • Payment:

    30% when order confirmed, 70% before shipment
  • Product Origin:

    China
  • Color:

    Customization
  • Shipping Port:

    Shanghai, China
  • Lead Time:

    30~60 days Ex Works after order confirmation
  • Material:

    CF8M
  • Method of Operation:

    Lever
Inquiry now
Product Detail

Specification table

Type

Butterfly Valve

Size

3’’

Pressure

150LB

Structure

Double Offset; Double Eccentric, Soft Seated

Connection Type

Wafer type

Operation

Lever operation

Design Code

API 609

Pressure Standards

ASME B16.34

Test & Inspection 

API 598

Body Material

CF8M

Temperature Range

-30℃~+180℃

Application

Water, Oil, Gas


Design features

1. Rational design, compact structure, easy to install and disassemble, maintenance-friendly

2. Dual eccentric structure reduces the friction onto the seal ring and prolong the service life.

3. Leakage free. Can be used in ultra-high vacuum conditions.

4. Different seals, plates, shafts and other materials are available for a wide range of media and temperature.


Technical Drawing


Report Available

Along with each order, Dervos will provide inspection reports and material test reports free of charge after shipment. All these certificates will let you have a clear picture of inspection process and results. Plus, these reports can be used for traceability. 


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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.

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Leave a message

    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.

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