English

English

Get a Quote
Products

Hot Products

Company News

Business Team Visits Europe for In-Depth Customer Engagement
Business Team Visits Europe for In-Depth Customer Engagement
2025-11-20

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.

Maintenance Tips to Extend the Service Life of Butterfly Valves
Maintenance Tips to Extend the Service Life of Butterfly Valves
2025-11-14

Butterfly valves are widely used as regulating and shut-off devices in industrial piping systems, valued for their simple structure, lightweight design, and rapid open-close operation. They find applications across water treatment, chemical, metallurgical, power, oil, and gas industries.   However, even high-quality butterfly valves can experience performance degradation if proper maintenance is neglected over long-term operation.This article explores the structural features, common issues, and maintenance practices to help effectively extend the service life of butterfly valves.   1. Understanding the Operational Characteristics of Butterfly Valves   A butterfly valve primarily consists of a valve body, disc, stem, sealing elements, and an actuator. Its operation relies on the rotation of the disc, driven by the stem, to control fluid flow.   During operation, the disc remains immersed in the fluid, subject to erosion, corrosion, and pressure shocks. Therefore, the valve’s lifespan is closely related to sealing performance, material selection, and the operating environment.   2. Common Factors Affecting Butterfly Valve Lifespan   Frequent Operation and High Differential Pressure High-frequency cycling or prolonged operation under high pressure and flow velocity can cause valve seat wear and stem seal aging.   Corrosive Media and Sediment Build-Up Chemical fluids or particulate-laden media can corrode the disc and clog sealing surfaces, reducing smooth operation.   Improper Installation Misalignment between the valve and pipeline, or uneven bolt tightening, may lead to eccentric disc friction and damage to sealing elements.   Lack of Regular Maintenance Neglecting routine cleaning and lubrication can increase operating torque, accelerate seal wear, and shorten the valve’s overall service life.   3. Maintenance Tips to Extend Butterfly Valve Lifespan   1. Proper Installation as the Foundation Ensure the valve body is aligned with the pipeline center to avoid eccentric stress. Use appropriate gaskets between the valve and flange to prevent localized stress. For actuated butterfly valves, confirm correct travel adjustment to avoid exceeding torque limits.   2. Regular Cleaning and Inspection Periodically remove deposits and debris from the disc surface to prevent seal surface damage. Check stem packing and seals; replace immediately if signs of aging are detected. For pipelines carrying particulate-laden media, flush the valve regularly to prevent clogging.   3. Lubrication and Corrosion Protection Apply grease to the stem, bearings, and drive components regularly to maintain smooth operation. For valves operating in seawater or corrosive environments, select corrosion-resistant coatings or materials such as aluminum bronze or duplex stainless steel.   4. Proper Operation and Control  Avoid rapid or forced operation to prevent disc deformation from impact. If the ...

Check Valve Maintenance: When to Replace and How to Fix Common Issues
Check Valve Maintenance: When to Replace and How to Fix Common Issues
2025-11-06

A check valve is a critical device that prevents backflow, widely used in water treatment, oil & gas pipelines, chemical processing, and steam systems.   After long-term operation, check valves may experience issues such as leakage, vibration noise, or sticking. If not addressed promptly, these problems can reduce system efficiency and even cause equipment damage or safety hazards.   So, how can you tell if a check valve needs replacement? Which faults can be repaired, and which require a full replacement? This article provides a systematic guide.   1. Basic Operating Principle of Check Valves   The primary function of a check valve is to automatically prevent backflow. When fluid flows in the intended direction, the valve disc is pushed open by pressure; when flow reverses, the disc closes automatically, using either its own weight or a spring, preventing backflow.   Common types include: Lift Check Valve Swing Check Valve Dual Plate Wafer Check Valve Ball Check Valve    Although their designs vary, the key criteria for determining whether a check valve needs replacement remain the same: sealing performance, operational smoothness, and structural integrity.   2. How to Determine if a Check Valve Needs Replacement   Visible Leakage (Internal or External) If fluid continues to flow backward when the valve is closed, it indicates significant wear or deformation of the sealing surfaces, preventing an effective seal. If the leakage exceeds system tolerances and cannot be corrected by cleaning or resurfacing, the valve or its sealing components should be replaced.   Sticking or Inflexible Valve Disc After long-term operation, the valve stem, guides, or disc may become stuck due to scaling, corrosion, or debris. If cleaning, descaling, or lubrication fails to restore smooth operation, replacement is recommended.   Excessive Noise or Vibration Frequent opening and closing or rapid disc rebound can cause vibration or knocking sounds. This is usually due to spring failure, loose valve components, or worn guides. Persistent or frequent noise should trigger inspection of the valve’s structural integrity and consideration for replacement.   Corroded or Cracked Valve Body or Cover Exposure to acidic, alkaline, or high-temperature fluids can corrode or crack the valve body, compromising structural strength and posing safety risks. Such damage cannot be repaired and requires full valve replacement.   Frequent Backflow or Abnormal System Pressure Fluctuations Poor sealing or delayed valve response can cause system pressure variations, including water hammer. If repeated adjustments do not resolve the issue, it indicates aging of the internal spring or disc mechanism, necessitating timely replacement.   3. Common Fault Diagnosis and Solutions   Fault: Valve fails to close completely, causing backflow Cause: Worn sealing surfaces, deformed disc, or trapped debris Solution: Remove ...

Knife Gate Valve
加载中...

2" 150LB Knife Gate Valve CF8 Lug Handwheel

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.

  • 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:

    ASTM A351 CF8
  • Method of Operation:

    Hand Wheel
Inquiry now
Product Detail

Product Description

Type

Knife Gate Valve

Size

2"

Pressure

150LB

Connection

Lug

Operation

Hand Wheel

Body Material

ASTM A351 CF8

Design Norm

MFS

Flange Connection

AS2129 TABLE E

Face to Face

EN558

Test & Inspection Code

MSS SP-81

Applicable Medium

Water, Oil and Gas

Features

1. Simple structure, easy to manufacture and maintain;

2. Simple structure, low fluid resistance, good sealing performance, and fast opening and closing.

Technical Drawing

Dimension Checking

Pressure Testing

Nameplate & Packing

Inspection report

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.

Related Products
Electric Actuated Gate Valve
Stainless Steel Knife Gate Valve Lug Electric 6 Inch

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.

Unidirectional Knife Gate Valve
Flanged Knife Gate Valve DN800 PN6 CF8M Gearbox

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

MSS SP-81 Manual Lug Type Knife Gate Valve Bi-directional
MSS SP-81 Manual Lug Type Knife Gate Valve Bi-directional

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.

Knife Gate Valve
DN150 PN10 Unidirectional Knife Gate Valve Wafer RF Cast Iron

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.

Gate Valve
Knife Gate Valve CF8 4 Inch 150LB Lug Type Handwheel

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.

DN200 PN25 Y Type Strainer, RF Connection, Body 1.0619, BS EN 13709
DN200 PN25 Y Type Strainer, RF Connection, Body 1.0619, BS EN 13709

DN200 PN25 Y Type Strainer is made according to BS EN 13709 standard. The valve body is made of EN 10213 1.0619. It has the structural characteristics of Y-shaped, mesh size: 1.6 mm, without drain plug. Its connection mode is RF.

Forged Steel Gate Valve
API602, Body A105N, 1'' 800LB Forged Steel Gate Valve, SW Connection

1" 800LB forged steel gate valve is made according to API602 standard. The valve body is made of ASTM A105N. It has the structural characteristics of rigid wedge. Its connection mode is SW. And it has polish rod with single acting pneumatic head operation mode and its maximum on/off time is 5 seconds.

Cast Steel Gate Valve
DN80 PN25 Cast Steel Gate Valve Body 1.0619 H.W. DIN3352

DN80 PN25 Cast Steel Gate Valve is made according to DIN3352 standard. The valve body is made of 1.0619+STL. It has the structural characteristics of Bonnet, Straight-through Type. Its connection mode is EN1092-1 B. And it has hand wheel operation mode.

Pressure Balance Plug Valve With Lever
Inverted Pressure Balanced Lubricated WCB 2 Inch Plug Valve

Inverted Pressure Balanced Lubricated Plug Valve is 2 inch and WCB body with metal seated. Apply to temperature lower than 80℃. Quick Detail  Type Plug Valve Size 2” DesignPressure 150LB Construction Lubricated Type Plug Valve Connection Type Flange Connection Operation Lever/Wrench Design Code API6D Face to Face ASME B16.10 End Connection ASME B16.5 Pressure & Temp ASME B16.34 Test & Inspection  API6D Body Material A216 WCB Temperature Range <80℃ Application WOG

20 Inch API600 NRS Gate Valve Solid Wedge FF BB Class150 Gearbox
20 Inch API600 NRS Gate Valve Solid Wedge FF BB Class150 Gearbox

This butch of gate valves are ranged from 3 inches to 32 inches. With non-rising gate valves and solid wedge, which are not regularly found in such big sized valves, these gate valves are quite special and reliable.

Body WCB, 8 150LB Cast Steel Globe Valve, RF Connection, Handwheel
Body WCB, 8" 150LB Cast Steel Globe Valve, RF Connection, Handwheel

8" 150LB cast steel globe valve is made according to BS 1873 standard. The valve body is made of ASTM A216 WCB+STL. It has the structural characteristics of straight through, rising stem, plug valve disc. Its connection mode is RF. And it has hand wheel operation mode.

Gate Valve
API Cast Steel NPS 8 Class150 Gate Valve OSY Handwheel

Dervos is a proud industrial API 600 cast steel gate valve manufacturer in China. Our stainless steel gate valves, carbon steel gate valves, and alloy steel gate valves are available in all trim configurations.

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.

Home

Products

about

contact