Overview
Plug valves have the shape of cylinders or cones and can be rotated inside the valve body to control fluid flow. Typically, plug valves have one or more hollow passageways placed horizontally to allow flow through the valve when it is open. The most common type of plug valve has two ports, one open, one closed. One passageway usually leads from the inbound direction to the outbound direction, with the handle and stem located on top. Plug valves also use quarter-turn valves, which are useful if the frequent and swift operation is required. Valves can have flanged ends, hub-type valve ends, or butt-welded valve ends.
Types and uses of plug valves
Despite the variety of plug valve types, there are four general categories, each with its own benefits.
Lubricated Plug Valve
The lubricated valve uses a lubricant made up of a base oil and viscosity improver (such as amorphous or fumed silica) that is injected under pressure between the plug face and the body seat to reduce friction and seal the ports. The valve manufacturers recommend lubricants compatible with the process fluid, and they frequently need to be resealed after only a few cycles, and in some cases, after every cycle. The Plug valve is typically utilize in applications that operate infrequently since they are considered high maintenance. Fluids with mildly abrasive particles can be effectively handled using lubricated plug valves. Dirty upstream applications, gas pipeline systems with bypass valves, and blow-down valves on valve stations and kickers are examples.
Non-Lubricated Plug Valve
A tapered or cone-shaped plug valve presses a polymeric sleeve against the body cavity by acting as a wedge. Friction between the plug mechanism and the body is reduced by the sleeve. In applications where maintenance needs to be kept to a minimum, such as sulfur or hydrogen fluoride services, or where liquid may become trapped or solidify, causing the valve to jam, non-lubricated plug valves are typically used instead of lubricated ones. The chemical and temperature compatibility of the materials used to make non-lubricated plug valves restricts their use.
There are three main types of non-lubricated plug valves:
- Lift-type plug valve
- Elastomer sleeved plug valve
- Fully lined plug valve
Eccentric Plug Valve
The plug valve is designed with a half plug, which is advantageous for applications that require a high seating force with minimal friction from the open to the closed position. These torque seated valves also have improved shut-off capabilities. In addition to flow control and isolation applications, eccentric plug valves are used in sludge and slurries, clean water, sewage, and air.
Expanding Plug Valve
In one unit, this complex plug valve incorporates several components that enable it to mechanically expand and perform both double blocking and bleeding functions. A plug valve has a mechanism that rotates between open and closed positions to protect both seals from the flow path. The seals are not in contact with the valve body during rotation, and slips expand onto the seat when the valve is closed to avoid wearing or abrasion. In applications that do not require double isolation, they are frequently used to prevent product contamination.
Types :
DESIGN
- Short Pattern
- Regular Pattern
- Venturi Pattern
Based on Ports
Double Port (Two Port) Valves
Dual-port valves have two ports through which fluid can enter or leave. They have two positions, open to allow flow and closed to stop it. Double port valves have one path through which flow passes. Typically, these ports are located at the parallel ends of the valve body, so the plugs are rotated 1/4 turn to change from the open to the closed position.
Multi-Port Valves
The valve of this type is used for diverting or combining flow. The flow from one port of a 3-way plug valve can be directed to either the second or third port. It can also be designed so that all three ports can be connected together, or so that the flow can alternate between the ports.
APPLICATIONS
In hazardous liquids and gases that are corrosive, plug valves function well as tight shut-off and on valves. The Valve suppliers and the valve manufacturers of plug valves ensure that the valves are used in the following applications:
- Oil piping systems
- High-pressure & Extreme temperature flow systems
- Chemical servicing
- Corrosive substances processing
The following are some common industrial uses for plug valves:
As Plug valves don’t get clogged, they are suitable for high-pressure systems. Additionally, they can handle corrosive and dangerous materials, which require special maintenance and replacement.
High-Pressure Flow Lines
Plug valves can handle high pressure, making them ideal for high-pressure applications such as cementing, acidifying, and handling high-temperature/high-pressure materials.
Upstream Applications
Lubricated plug valves are used here because they aren’t clogged and can handle corrosive materials. Maintenance is mandatory at short intervals because of these conditions.
Flow Control/Isolation
As the plug valves offer great flow control/isolation, they can easily seal off and separate the liquids so as to prevent contamination or mixing, which is essential in a high-pressure application.
Oil & Coal Slurries
These types of valves are not getting choke easily, so they can handle abrasive materials. They are also great for controlling and isolating fluids, so they are ideal for working with oil & coal slurries.
Advantages of plug valve
Plug valves have the following advantages:
- The design is simple and there are fewer parts.
- so it can open and close quickly.
- The valve offers minimal resistance to flow.
- With multi-port designs, fewer valves are essential and the flow direction can route.
- The system is reliable and leak-free.
- It is easy to clean and easy for maintenance even without removing the body from the piping system.
Disadvantages of plug valve
Plug valves have the following limitations or drawbacks:
- Rotation of the plug requires a high amount of friction, which results in greater force needed to operate these valves.
- For larger valves, actuators are mandatory.
- Compared to ball valves that have a similar design, these plug valves are more expensive.
- The pressure drop becomes a reason because of the smaller port.
Conclusion:
It is essential for the highly demanding working environment of the various industries that rely on valves as a control and function mechanism to have a properly designed and planned plug valve. Plug Valves provide a one-stop solution for all customer specifications, which are manufactured and supplied by Aira Euro Automation which in turn is fully compliant with industry standards. Our team of experts ensures that essential mechanisms are of superior standards in order to perform under extreme conditions. We also manufacture and supply industrial valves like Ball Valves, Control Valves, etc.
