The wafer dual plate check valve is also a type of check valve with a rotary actuation, but it is a double disc and closes under the action of a spring. The disc is pushed open by bottom-up fluid, the valve has a simple structure, the clamp is installed between two flanges, and the small size and light weight are low.
The wafer dual plate check valve has two spring-loaded D-shaped discs placed on a ribbed shaft across the valve bore. This structure shortens the distance that the center of gravity of the disc moves. This construction also reduces the weight of the disc by 50% compared to a single-disc swing-on check valve of the same size. Thanks to the spring load, the valve reacts very quickly to backflow.
The wafer dual plate check valve’s double-lobe lightweight construction makes seat sealing and operation more efficient.
The long-arm spring action of the double butterfly check valve allows the disc to open and close without rubbing the seat, and the spring acts independently to close the disc (DN150 and above).
The hinged support sleeve of the double-flap butterfly check valve reduces friction and minimizes water hammer when aborted through a separate disc (larger bore).
Compared to conventional swing check valves, wafer dual plate check valve construction is typically stronger, lighter, smaller, more effective, and less expensive. This valve meets the standard of API 594, for most diameters, the face-to-face size of this valve is only 1/4 of the conventional valve, and the weight is 15%~20% of the conventional valve, so it is also cheaper than the swing check valve. It is also easier to install between standard gaskets and pipe flanges. Because it is easy to handle and requires only one set of flange connection bolts, it also saves components during installation, saving installation costs and daily maintenance costs.
The double-flap butterfly check valve also has special construction features that make this valve a high-performance non-impact check valve. These features include no-clean opening, independent spring construction for most bore valves, and independent disc support systems. Some of these features are not available with check valves. The wafer dual plate check valve can also be designed with lugs, double flanges and an extended body.
First, the opening and closing process
The double-disc construction features two spring-loaded discs (semi-discs) suspended from a hinged pin that is vertical in the center. When the fluid begins to flow, the disc opens with a resultant force (F) acting on the center of the sealing surface. The counteractive spring support force (FS) is applied at a position outside the center of the disc face, causing the disc root to open first. This avoids the friction on the sealing surface that occurs when the disc is opened in older conventional valves, eliminating wear and tear on components.
When the flow rate slows down, the torsion spring automatically reacts, causing the disc to close and move closer to the body seat, reducing the travel distance and time of closing. When the fluid flows backwards, the disc gradually moves closer to the body seat, and the dynamic response of the valve is greatly accelerated, reducing the effect of water hammer and achieving impact-free performance.
When closing, the action of the spring force action point causes the top of the disc to close first, preventing biting and friction at the root of the disc, so that the valve can maintain the integrity of the seal for a longer time.
2. Independent spring structure
The spring construction (DN150 and above) allows for a greater torque to be applied to each disc and the disc closes independently as the industrial flow changes. Experiments have shown that this effect has resulted in a 25% increase in valve life and a 50% reduction in water hammer.
Each section of the double disc has its own springs that provide independent closing force and are subjected to a relatively small angular offset of 140° (fig. 3) instead of the 350° of a conventional spring with two brackets.
3. Independent disc suspension structure
The independent hinge structure reduces friction by 66%, which greatly improves the valve’s reactivity. The support sleeve is inserted from the outside hinge so that the upper hinge can be independently supported by the lower sleeve during valve operation. This allows both discs to react quickly and close at the same time, achieving excellent dynamic performance.
Fourth, the connection mode with the pipeline
Wafer dual plate check valves and pipes can be connected with clamps, lugs, flanges, and clamps.
You can click on our website for more information Butterfly Valve, Flow Controlled by TWS Valve (tws-valve.com)
Post time: Oct-24-2024
