Difference Between Lugged and Wafer Butterfly valves

Butterfly valves play a very important role in controlling the flow of fluids in pipelines. Among the various types of butterfly valves, lug butterfly valves and wafer butterfly valve are widely used due to their high efficiency and ease of installation. Below is a detailed comparison of the two, highlighting the key differences between the two:

INSTALLATION MECHANISM: Lugged butterfly valves are characterised by protruding lugs around the periphery of the flange. 

These lugs are threaded and tapped for mounting bolts to secure the valve directly to the pipeline from both sides.

• Installation Flexibility: One of the main advantages of lug butterfly valves is the ability to disconnect from one side of the pipeline and not affect the other side. This ability is often referred to as "dead-end service" and makes maintenance and replacement easier and more efficient.

• METHOD OF OPERATION: These valves can be operated manually, hydraulically, pneumatically, or by other braking methods, and are versatile enough to meet a wide range of applications and operational needs.

• Configuration Versatility: Lug Butterfly Valves are available in a variety of configurations, depending on the number of lugs, for different sizes and specifications of pipelines.

Advantages and disadvantages of lug butterfly valve

Advantages：

Easy to install and remove:

Due to its unique lug design, the Lugged Butterfly Valve can be bolted directly to both sides of the pipe, eliminating the need for additional support structures. 

It can be repaired or replaced without complete disassembly of the pipe, which saves the user a great deal of time and cost.

Space saving:

Compared with other types of valves such as ball valves, the Lugged Butterfly Valve is small in size, light in weight and occupies less space, 

which is suitable for installation environments with limited space.

Cost Effective:

Butterfly valves with lugs are generally more economical than other valve types. Their simple design and low manufacturing costs make them a cost-effective choice for many industries.

Adaptable to many applications:

Suitable for a wide range of application scenarios, especially in the chemical, oil, gas, food and water treatment industries. Due to its robust construction, 

it is also suitable for high pressure and high temperature working conditions.

Low operating force:

Butterfly valves usually require low force to operate, especially when pneumatic or electric actuators are used, enabling easy remote control.

Disadvantages

Poor sealing (compared to full bore valves):

Although the Lugged Butterfly Valve seals well enough, it usually does not seal as well as a full bore valve, such as a ball valve, at high pressures or where complete sealing is required. 

For some severe sealing requirements, other types of valves may need to be considered.

Limitations on fluid type:

In some special fluids (such as high viscosity fluids or fluids containing particles), the sealing effectiveness of butterfly valves may be affected and wear or leakage may occur.

Operating Pressure Limitations:

While the Lugged Butterfly Valve is suitable for general low and medium pressure piping systems, 

it has limited adaptability under very high pressure conditions and may not provide the same reliability as a high pressure valve.

Susceptible to mechanical wear:

Due to the way the butterfly disk rotates inside the valve, it may be subject to impact or friction in the flow of liquid, 

leading to some wear, especially in the case of frequent opening and closing.

Less adaptable than full passage valves:

For applications requiring full-flow access (e.g., when piping requires high-flow circulation), 

the Lugged Butterfly Valve may not be designed to provide as much flow as some full-bore valves, and therefore its performance may be limited in high-flow situations.

• Mounting Mechanism: The Butterfly Butterfly Valve design features a clamping mechanism between the pipe flanges. Long bolts run through the entire assembly and hold the valve in place by pressing the flanges together.

• SERVICE AND MAINTENANCE: Unlike lug type butterfly valves, the Button Clamp Butterfly Valve does not allow for easy disconnection on one side. To service the valve, fluid flow must be completely stopped and the piping disconnected at the flange.

• Space and Weight: Wafer-type butterfly valves are generally more compact and lighter than lug-type butterfly valves, which is an advantage in applications where space and weight are critical factors.

  
  

Advantages and disadvantages of Wafer Butterfly Valve

Advantages

Compact and lightweight:

Counterclamp butterfly valves are small in size, light in weight, and take up little space, making them ideal for space-constrained installations. Compared with other types of valves, 

it saves more installation space, especially for those systems with high space requirements.

Easy installation:

The installation of this butterfly valve is very simple, it only needs to be clamped between two pipe flanges by bolts, without an additional support structure. 

This design reduces the time and labor required for installation and lowers installation costs.

Cost Effective:

The Wafer Butterfly Valve is typically low in manufacturing cost, simple in construction, and low in material consumption, making it a very cost-effective option for many industrial applications.

Adaptable to a wide range of applications:

It is suitable for use in many fluid control systems, especially in low to medium pressure environments, and is widely used in piping in oil, gas, water treatment, chemical and other industries. 

The Wafer Butterfly Valve is an ideal choice for applications where high pressure and high flow rates are not required.

Easy Operation:

Butterfly valves usually require less force to operate, especially when operated by pneumatic or electric actuators, enabling fast and precise flow control. Ideal for applications requiring frequent opening and closing.

Efficient fluid control:

Because of its simple design and low resistance to flow as the fluid passes through it, the butterfly valve performs well in many applications where energy savings and high fluid control efficiency are required.

Disadvantages

Do not seal as well as other types of valves:

The Wafer Butterfly Valve may not provide the same sealing effectiveness as a ball valve or other high sealing performance valves in certain high pressure and tight sealing required applications. 

Although it is typically suitable for low to medium pressure systems, sealing performance may be limited in high pressure systems.

Withstand pressure limitations:

The Wafer Butterfly Valve is typically designed for lower pressures than other more robust valves. For high pressure systems, a more robust valve, such as a double or triple eccentric butterfly valve, may be required to meet the demand.

Wear-prone seals:

Due to the way the butterfly disc rotates and the friction of the fluid, the seals of the Wafer Butterfly Valve are prone to wear in frequent opening and closing and high flow rate environments and may require more frequent maintenance and replacement.

Less suitable than full bore valves:

If a piping system requires high flow rates and full flow capacity, the Wafer Butterfly Valve design may restrict flow, especially in high flow or large piping applications, and may not perform as well as a full bore ball valve.

Not for use with highly viscous fluids or particulate matter:

When handling highly viscous fluids, slurries, or media containing particulate matter, the Wafer Butterfly Valve may face problems with poor sealing and wear. Other types of valves, such as ball or diaphragm valves, need to be considered.

The main difference between the two types of butterfly valves is installation and maintenance. A tab butterfly valve offers greater disconnect and maintenance flexibility without affecting the entire system, 

while a butt-lug butterfly valve is more compact but requires complete disconnection of the pipework to carry out maintenance. Choosing between the two depends largely on your specific operational needs and the nature of your pipework.