Plug valves are quarter-turn on-off valves. They are shaped like a cone or cylinder & can be internally rotated in the body of valves for controlling applications. Plug valves contain one or even more passageways to permit ease of fluid flow. There are different types of plug valves. Among them, eccentric plug valves are the most used ones for wastewater. Read this blog to know more about eccentric plug valves(Eccentric plug valve).
What are eccentric plug valves?
These are a kind of rotary control valve which have flow-restricting plug-shaped members that obey an eccentric path when they rotate. These plugs do not have contact with the seats before a few degrees of shutoff position. The design of eccentric type plug valves usually uses a half plug which is beneficial for various applications requiring higher seating force but with less friction from an open to a closed position. The features of such valves are ideal for enhanced shut-off capabilities.
What are the applications of eccentric plug valves?
Eccentric plug valves were first used in the paper industry in the 1930s. These valves are beneficial for handling fluids with some solid content quite the same as the gate valves but the plug valves offer another benefit of quarter-turn valves like modulating services. Eccentric plug valves are specially designed for slurry control, liquid, vapour and gas in both general and any demanding applications. They offer the best control performance to users. Their capacity to tackle impure fluids efficiently makes them suitable for petrochemicals, refining, natural gas, chemical and other manufacturing applications. They are used in a broad range of flow control & isolation applications like dirty water, clean water, sludge, sewage etc.
A snippet about eccentric action:
Eccentric plug valves have a unique feature and that is their seat from the shaft is offset by offering an effective eccentric action. Usually, the mid-size eccentric plug valves may have a second offset of half-inch. When this type of valve opens in a counterclockwise direction about the shaft, its double offset allows the plug to get lifted off the seat when it rotates. This lifting action helps in avoiding wear in grainy wastewater services. The direct pressure is given on the end portion of the valves’ opposite seat. Direct pressure is assisted with the sealing functions of eccentric plug valves as they thrust the plug into the valves’ seat tightly. Eccentric plug valves also seal the pressure in a reverse pressure direction but you need to turn the plug clockwise through the seat’s centre. Due to the eccentric action, closing rotation is much greater, and the seal is tighter.
Linear Flow Characteristics of eccentric plug valves:
Eccentric plug valves have the characteristics of high linear flow control & unique design to lessen wear and elevate longevity. The shaft sealing system of plug valves helps in protecting both radial & thrust bearing assembly by avoiding grit ingress. The seat of eccentric plug valves is mostly constructed with 95 per cent of pure Nickel. It guarantees full encapsulation(Eccentric plug valve).
What are the prominent features of eccentric plug valves?
There are many features of this type of plug valve:
- The action of these valves offers a positive shut-off with very low torque and wear-resistant action.
- The non-clog design of eccentric plug valves is advantageous. When an unrestricted fluid flow area is agglomerated with a fine streamline contouring, then it allows a passage of solids to avoid clogging and offers a lesser head loss.
- The full top access cover of these types of plug valves provides accessibility for any inspection with no removal of the valves from your line.
- Usually, eccentric plug valves come with V-type packing which makes them replaceable as well as field adjustable without removal of motor actuators or worm gear.
- Eccentric action guarantees less contact as the rotation leads to lifting the plug in & out from the seat.
- Stainless steel fastening and epoxy coating externally and internally can provide a long life for these valves with less maintenance.
Some installation tips for eccentric plug valves:
Due to the eccentric plug valves’ geometry and usage in various wastewater services, some special installation is recommended. The valves must be installed with the shaft in a horizontal position. Why? It is because when the valves are opened, the plug is right at the pipe’s top portion. You must install these valves for vertical pipes, notwithstanding the fluid flow direction with the end of the seat, so that the solids settled can not get collected in the valves.
So, we hope this blog has helped you to understand more about eccentric plug valves. Strong seated eccentric plug valves are unique valves designed especially for tackling wastewater fluids and can even perform best with abrasive fluids. You can reach out to a reliable supplier of eccentric plug valves in the Middle East and GCC region.
