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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...

Nozzle Check Valve
加载中...

2 Inch 150LB Nozzle Check Valve LCB

The 2inch axial nozzle check valve is the preferred solution for preventing return flow or shocks on critical process equipment. Thank for its LCB body, the valve is capable for working temperature down to -46 degree Celsius.

  • 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:

    LBC
  • Method of Operation:

    Non
Inquiry now
Product Detail

Quick Detail

Type

Check Valve

Size

2 Inch

DesignPressure

150LB

Construction

Axial Flow Type

Connection

RF

Design & Manufacture

API 6D

End to End

API 6D

End Flange Dimensions

ANSI B16.5

Test & Inspection 

API 6D

Body Material

LCB

Trim Material

SS316

Temp Range

-46℃~350℃

Media

W.O.G.

 

Our nozzle check valve, characterized by an optimized flow profile and unique dual-spring design, solves common check valve operational issues while improving on the dynamic response and pressure loss of existing nozzle check valve designs.

 

Features

-Low pressure loss

-Unique dual-spring design for fast, dynamic, non-slam response

-Reliable, maintenance-free operation

 

Technical Drawing


Witness Tests



Nameplate&Packing


Why choose Dervos as your partner?


One Stop Service

Here in Dervos, we can provide you with one stop service by our complete product list, it means, you don’t need to search for various suppliers for different types of valves, and it will surely save your time and energy. All you need to do is choose Dervos and we will provide complete solutions to you.

 

On Time Delivery

Dervos keeps a high percentage of on time delivery. Why could we achieve that? Our purchasing team follows the order very closely. Plus, our QC and sales person will also do monitoring job on each order.

 

Strict Quality Control

All the members in the QC team are very experienced and professional. For each order, they will check the raw material, manufacturing process, do the pressure testing on shell and seal, and check the valve dimension per assembly drawing. Lastly, they will inspect the painting and packaging.



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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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