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Advantages of V-port Valves
Advantages of V-port Valves

The V-ball valves or V-port ball valves are similar to traditional ball in which there is a V-notch on a ball-shaped disc to control flow by a rotating quarter-turn motion. The “V-port" is a particular design that bring about precise flow and the ability to regulate and control flow by V balls of  different degrees. These special valves are used in a wide range of chemical applications, including the most challenging services with many advantages.   Flow Modulating The accuracy of V-ball valves provides equal percentage flow characteristics. As the ball rotates, desired flow rates can be achieved by positioning the ball anywhere between 0° and 90°.   Bubble tight shutoff V-ball valves have the ability to close tightly. Therefore, no other shutoff valves is required when using a V-ball valve on a globe valve.   Lower pressure drop V-ball valves also have a higher coefficient of flow (Cv) than the same size globe valve, which directs the flow and uses a plug to control the flow through the valve. This means that the flow rate achieved by one shut-off valve can be achieved with a smaller V-ball size.   Higher shutoff pressure. A 90°rotation of the ball allows the V-ball to close at a higher operating pressure. This therefore allows the use of lower torque actuators, resulting in cost savings and increased efficiency for the end user.

Know and Know More About Changeover Valve
Know and Know More About Changeover Valve

There are quite a few types of changeover valves, and according to different standards, there are different subdivisions. But in general, it is mainly four kinds, for motorized changeover valve, manual changeover valve, solenoid valve and electro-hydraulic changeover valve.   1. What is a changeover valve?   Changeover valve, from a professional point of view, is a kind of direction-change valve. It is mainly used to achieve the flow of hydraulic oil, cut off the machine changeover operations, pressure relieving, as well as sequential action control, so its use is very wide.   2. The working principle of reversing valve   The changeover valve uses a  driving mechanism outside the valve to rotate the drive shaft, and then activates the valve plate, etc. So that the fluid can flow into the outlet of the lower part of the valve, and can be changed from time to time to achieve the purpose of periodically changing the flow direction.   3. Changeover valve classification  (1) Motorized changeover valve, it is also known as a stroke valve.    (2) Electromagnetic changeover valve, electromagnetic changeover valve is the use of electromagnetic attraction to manipulate the spool changeover control valve.    (3) Electro-hydraulic changeover valve, electro-hydraulic changeover valve is a composite valve composed of solenoid valve and hydraulic changeover valve.    (4) Manual changeover valve, manual changeover valve is a changeover control valve with a manual lever to manipulate the spool shift direction-changing valve.  

How to extend the service life of lined valves?
How to extend the service life of lined valves?

Among the anti-corrosion materials, PTFE has incomparable excellent performance. In addition to outstanding chemical stability, it also has satisfactory anti-fouling and anti-stickiness, small dynamic and static friction coefficient, good anti-wear performance. Using it as a valve opening and closing the sealing material, the friction between the sealing surface and required operating torque will be reduced, hence product life increases. the application scope can also be extended to the food, pharmaceutical industry and so on. Fluorine lined valves, also known as anti-corrosion valves, are usually found in harsh working conditions. The media is either toxic and harmful chemicals, or pretty corrosive acids and bases or organic solvents. That means improper use and operation will elicit significant economic losses and serious consequences. Applicable media: various concentrations of acid and alkali salt and certain organic solvents. Fluorine is extolled as the world's most ideal anti-corrosion materials, has been widely used in the rotational molding of large equipment and piping lining. Correct use and maintenance of the valve can extend the service life of fluorine lined valves, then what can be done to effectively protect it? 1. Carefully read the instruction manual before use. 2. Use it within the range of pressure, temperature and media given by the nameplate or instruction. 3. To prevent fluorine lined valves from excessive piping stresses due to temperature changes, temperature changes should be minimized and U-shaped expansion joints should be added before and after the valve. 4. For some unstable and easily decomposed media (such media will expand after decomposition,  resulting in an abnormal pressure rise) and media that can cause valve damage or leakage, measures should be taken to eliminate or limit the factors that cause the decomposition of unstable media. 5. For fluorine lined valves in pipelines of toxic, flammable, explosive, highly corrosive media, it is strictly prohibited to replace the packing under pressure. Even the valves are designed with sealing part, it is not recommended to replace the packing under pressure either. 6. For pipelines with self-combustible media, measures should be taken to ensure that the ambient and working temperatures do not exceed the self-combustibility point of the media to avoid the danger from sunlight or external fires.

WCB Changeover Valve PN40 Handwheel

WCB Changeover Valve PN40 Handwheel

The changeover valve is combined by two valves that are different from nominal diameter--one is DN100, the other is DN150. A handwheel is put on the right side of the valve to help control the large WCB-made device. Designed as per DIN 3356, the valve is usually put in the oil industry.

  • Payment:

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

  • Color:

  • Shipping Port:

    Shanghai, China
  • Lead Time:

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

    ASTM A216 WCB
  • Method of Operation:

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Product Detail

General Discrption

Changeover , also called selector valve, is a three way device usually for changing the direction of the flow in pipelines. It also can be put in the situation of two safety valves and a pressurized system as a pressure relief system where the changeover valve ensures that we always have one standby valve ready for emergency. The condition also permits regular maintenance can be carried out without interrupting the work of the whole device.

The simple design from Dervos allows easy assembly, dis-assemble and easy maintenance. The valve also can handle various applications--high temperatures, cryogenic service, dangerous fluids and many others.

Design Features

Full Bore: The full-bore channel brings superior transporting performance. This valve is also designed to minimize the pressure drop and flow-resistance.

Zero Leakage: With emission-free packing and the static sealing part of the body, which is double-sealed by oval-ring and metal jacketed graphite gasket, the valve meets the demands of corresponding working conditions.

Long service life: The valve enjoys easy maintenance and long service life, which benefits from the plane sealed sealing face of the valve and the alloy welding technology.

Quick Detail


Changeover Valve

Nominal Diameter





Bolted Bonnet





Design & Manufacture

DIN 3356

End to End 


Flange End Dimension

EN 1092-1 B1

Test & Inspection 

EN 12266-1

Temperature Range


Body Material


Big Disc

ASTM A105+13Cr




Technical Drawing


Dervos Quality Checking System

In Dervos, we control quality throughout the whole manufacturing process.


Casting inspection:

We can find out the problem of raw material, such as shoddy casting, unqualified wall thickness, chemical composition and so on, which ensure that you will not be cheated.  

Machining Inspection:

On the one hand, we could ensure machining accuracy through this process. On the other hand, we could find out machining mistake as early as possible, to win more time for repairing and remaking


Final Inspection:

Final inspection activities include document and QC record review, visual examination, dimension check, pressure test, painting and packing check. You don’t need to come and inspect in person and all the documents could be provided as proof. 

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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.