English

English

Get a Quote
Products

Hot Products

Company News

Installation of Large Diameter Ball Valves
Installation of Large Diameter Ball Valves
2026-03-09

Large diameter ball valves are commonly used in industries such as petroleum and chemical processing, power generation, long-distance pipeline transportation, and large-scale water treatment systems. If installation is not performed correctly, it may lead to sealing leakage, valve jamming, or structural stress damage. Therefore, proper installation practices are essential to ensure long-term stable operation.   1. Pre-installation Inspection   If pre-installation inspection is insufficient, operational failures are more likely to occur during service. First, inspect the valve body for transportation damage. If scratches, impact marks, or deformation are found on the valve body or sealing surfaces, installation should be stopped and the supplier should be contacted.   Next, verify valve model, pressure rating, and connection standards. If the system design pressure does not match the valve pressure class, operational safety risks may occur. For example, if a low-pressure class valve is mistakenly used in a high-pressure pipeline system, the valve body may experience plastic deformation under water hammer impact.   It is also necessary to check the condition of the ball surface and sealing rings. If there are scratches on the ball surface, sealing performance will be reduced. This is especially critical in gas transmission systems where micro-leakage is more likely.   2. Installation Direction   Large diameter ball valves usually have a flow direction marking. If the installation direction is incorrect, the following problems may occur: If the fluid flow direction matches the design direction, the operating torque will remain more stable. If the valve is installed in reverse, the stem may experience increased mechanical load, which will accelerate stem wear during long-term operation. For double-seal bidirectional ball valves, although bidirectional flow is allowed, installation according to the marked flow direction is still recommended to ensure more uniform sealing stress distribution. In high-temperature or steam systems, if the installation direction is incorrect, thermal expansion may accelerate sealing ring aging.   3. Pipeline Stress Control   Large diameter ball valves are heavy. If installed without proper support, additional bending moments may be transferred to flange connections. If pipeline systems experience axial displacement, pipeline supports should be installed for segmented fixation. If support structures are not provided, the valve body may bear long-term gravitational tensile load, eventually causing flange seal failure. It is generally recommended to install independent supports on both sides of large diameter ball valves. If the pipeline system is subject to thermal expansion and contraction, expansion compensation devices must be installed; otherwise, sealing surfaces may gradually fail.   4. Bolt Tightening Process   Flange connections of large diameter ball valves usually ...

Unite Strength, Create the Future Together --Dervos Annual Grand Event Successfully Concluded
Unite Strength, Create the Future Together --Dervos Annual Grand Event Successfully Concluded
2026-03-02

This year’s Dervos annual conference was noticeably more grand and well-organized than in previous years.   In the morning session, each department delivered its annual work summary, reviewing key projects and achievements over the past year. Teams also openly shared the challenges encountered during implementation and the practical experience gained along the way.   Through this cross-department exchange, everyone developed a clearer understanding of one another’s responsibilities and workflows, laying a stronger foundation for future collaboration and communication.     In the afternoon session, the Outstanding Employee awards were presented. Each nominee shared their work achievements and practical experience, demonstrating a strong sense of responsibility and execution across different roles. It is precisely this proactive mindset, collaborative spirit, and down-to-earth working approach of Dervos employees that drives the team steadily toward its shared goals.     Showing up on time every single day throughout the year — that’s quite an achievement. Ian has now received the Perfect Attendance Award for two consecutive years.     During the annual conference, Dervos also presented medals and exclusive commemorative gifts to employees who have completed five years of service.     Dervos values the long-term dedication and consistent commitment of its team members, and sincerely appreciates the trust and contributions they have made over the years. For many at Dervos, the company is not only a platform for professional growth, but also a stage where shared goals and collective efforts come to life. In the evening, the annual conference transitioned into the banquet segment. Performances and interactive games were seamlessly interspersed, creating a relaxed yet organized atmosphere.     Laughter and cheers echoed throughout the venue, and in the moment the camera shutter clicked, the excitement and joy were captured in a single frame.     Eric said: "Let’s dream together, DERVOS's dream. A dream where we all play a part, piece by piece, it becomes a reality." For Dervos, the annual meeting is not just about "summarizing the year," but about bringing our hearts together, strengthening our resolve in doing the same thing, and then continuing to move forward, step by step, with steady progress.            

What Is the Difference Between Plug Valves and Ball Valves?
What Is the Difference Between Plug Valves and Ball Valves?
2026-02-20

Ball valves and plug valves differ significantly in several aspects, including structure, operating principle, mode of operation, flow control capability, sealing performance, and application scenarios. These differences enable the two types of valves to perform distinct roles in their respective fields.   Structural Differences   The ball valve, a design evolved from the plug valve, utilizes a spherical element as its core component. By rotating the ball 90° around the stem axis, the valve can be opened or closed. Its structure is straightforward, consisting primarily of a spherical closure element with a through-bore housed within the valve body.   In contrast, the structure of a plug valve is more complex. It comprises multiple components such as the valve body, bonnet, plug, seat, and stem. The closure element is a cylindrical or tapered plug that controls flow by rotating 90°, aligning or misaligning the port in the plug with the flow passage in the valve body to achieve opening or shutoff.   Operating Principle   The operating principle of a ball valve relies on the rotation of the ball to control the on-off flow of fluid. When the ball is in tight contact with the valve seat, the clearance between them is completely sealed, thereby preventing fluid leakage. When the ball rotates to a position disengaged from the seat, the fluid is allowed to flow freely through the passage inside the valve body.   The operating principle of a plug valve differs in that it primarily controls the flow passage by rotating the plug element to open or close the valve. In a plug valve, the plug is connected to the stem and rotates together with it to achieve flow control. The closure element is a tapered plug with a port, and the flow passage is designed to be perpendicular to the axis of the plug. This configuration enables the plug valve to operate more efficiently and reliably during opening and closing.   The operation of a ball valve is notably simple, requiring only a 90-degree rotation to achieve opening or closing. This design allows the flow passage to be opened or shut off quickly and smoothly when the ball is rotated by 90 degrees, providing both convenience and efficiency. In addition, ball valves offer relatively low flow resistance in the fully open or fully closed position, making them particularly suitable for applications that require rapid on-off operation.   By contrast, the operation of a plug valve is comparatively more complex, as several turns are typically required to complete the opening or closing action. The valve plug is designed in a cylindrical or tapered form and regulates fluid flow through rotation. Nevertheless, plug valves demonstrate excellent performance in flow regulation, enabling precise adjustment of the flow passage diameter and accurate control of flow rate. However, due to the relatively complicated operating process, plug valves are not well suited for frequent operation...

Axial Flow Check Valve
加载中...

RTJ Connection, 3" 1500LB Axial Flow Check Valve, API6D, Body A995 4A

3" 1500LB axial flow check valve is made according to API 6D standard. The valve body is made of A995 4A. It has the structural characteristics of axial flow type, and structural length of 473mm. Its connection mode is RTJ.

  • 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:

    A995 4A
Inquiry now
Product Detail

Product Description

Type

Axial Flow Check Valve

Size

3"

Pressure

1500LB

Connection

RTJ

Body Material

A995 4A

Design Norm

API 6D

Face to Face Dimensions

APl 6D

End Flange Dimensions

ANSl B16.5

Test & Inspection Code

API 598

Temperature

-29 ~ 325°C

Applicable Medium

Water, Oil and Gas

Features

1. Compact structure, small footprint, suitable for installation in places with limited space;

2. Through design and material selection, good sealing performance can be achieved to prevent medium backflow.

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
Nozzle Check Valve
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.

6 300LB Axial Flow Check Valve, Wafer Type, Body SS2205
6" 300LB Axial Flow Check Valve, Wafer Type, Body SS2205, API594

6" 300LB Axial Flow Check valve is made according to API594 standard. The valve body is made of SS2205. It has the structural characteristics of Silent type. Its connection mode is Wafer Type.

Axial Flow Check Valve
2”CL150 Axial Flow Check Valve RF API6D

2”CL150 Axial Flow Check Valve is made according to API 6D standard. The valve body is made of ASTM A352 LCB+316SS. It has the structural characteristics of axial flow. Its connection mode is RF.

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.

Butterfly Valve
API 14" 150LB High Performance Double Eccentric Butterfly Valve WCB

14" 150LB butterfly valve is made according to API 609 standard. The valve body is made of WCB. It has the structural characteristics of double eccentric and high performance. Its connection mode is lug type. And it has turbine with locking device operation mode.

6 Inch Dual Check Valve
Wafer Check Valve AL Bronze C95800 Dual Disc 6 Inch

The dual disc wafer check valve is designed as per API 594 and tested per API 598. The bronze non return valve is applicable for sea water. Quick Detail Type Check Valve Size 6'' DesignPressure Class 150 Construction Dual Plate Type, With Retainer Connection Wafer Type Design & Manufacture API 594 End to End ASME B16.10 Connection ASME B16.5 Pressure & Temp ASME B16.34 Test & Inspection API 598 Body Material Aluminum Bronze C95800 Trim Material Aluminum Bronze C95800 Media W.O.G. Dervos Inspection after Valve Assembly Valve quality is one of perspectives we care about most. In Dervos, quality control starts from raw material, machining, assembly to pre-shipment inspection. After assembly, the quality checking team will do visual checking, dimension checking, hydraulic testing and air testing. Every order must pass the test per inspection standards. Otherwise our quality checking team will not release the shipment. Inspection Reports Documents can be used to prove how we control valve quality. Along with every order, Dervos will provide clients with an inspection report & a 3.1 mill test report for free. In Dervos inspection report, you will see the actual results of dimension checking and pressure testing along with painting and packing picture. All these info are shown through data and clear pictures.   In 3.1 mill test report, we will show you the chemical composition, mechanical property and heat number for valve body, bonnet, stem, disc and so on.  

Knife Gate Valve
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.

Cast Steel Gate Valve
DN200 PN10 Cast Steel Gate Valve Body WCB EN1092-1 B

DN200 PN10 Cast Steel Gate Valve is made according to EN1984 standard. The valve body is made of A216 WCB+STL. It has the structural characteristics of Bonnet , Flexible Wedge. Its connection mode is EN1092-1 / B. And it has hand wheel operation mode.

Line Blind Valve
DN50 CL150 High Temperature Cam-Slide Line Blind Valve Stainless Steel

Line blind valve is a kind of gate valve that cuts off gas medium manually, electrically or pneumatically or hydraulically. It is generally divided into electric blind valve, hydraulic blind valve, closed plug valve and electric open blind valve.

Double Eccentric Butterfly Valve
API609, 4" 150LBS Double Eccentric Butterfly Valve, Body WCB, Lug Connection

4" 150LBS double eccentric butterfly valve is made according to API 609 standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of double eccentric. Its connection mode is lug. And it has lever with lock operation mode.

Gate Valve
1" 300LB Forged Steel Gate Valve LF2 API602

1" 300LB gate valve is made according to API 602 and ASME B16.34 standard. The valve body is made of A350-LF2. It has the structural characteristics of bolt cover, exposed rod, OS&Y, reduced diameter. Its connection mode is RF integral flange. And it has polished rod operation mode.

Swing Check Valve
Body WCB, 4" 600LB Swing Check Valve, RF Connection, API6D

4" 600LB swing check valve is made according to API 6D standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of bolt cover, swing type and external pin. Its connection mode is RF.

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