The Difference Between A Lug And Wafer Butterfly Valve
Butterfly valves are a type of quarter-turn valve used to control the flow of fluids (liquids or gases) through a pipeline. They operate by using a metal disc or vane mounted on a rod in the center of the pipe. When the valve is closed, the disc is perpendicular to the flow, blocking it, and when the valve is fully open, the disc is parallel to the flow, allowing for unrestricted flow. There are two main types of butterfly valves: lug butterfly valves and wafer butterfly valves. Here's a comparison between the two:
Design and Installation:
Lug Butterfly Valve: Lug-style butterfly valves have threaded inserts, known as "lugs," on both sides of the valve body. These lugs allow the valve to be installed between two flanges using bolts. The valve can be installed in a system using just two sets of bolts and nuts, without the need for additional hardware.
Wafer Butterfly Valve: Wafer-style butterfly valves do not have lugs. Instead, they have a wafer-like body with holes that align with the pipeline flanges. The valve is placed between the flanges, and bolts pass through the valve body and flanges to hold the entire assembly together. A separate set of bolts and nuts is required for installation.
Installation Application:
Lug Butterfly Valve: Lug-style valves are used in applications where the pipeline requires the valve to be installed and removed without disturbing the entire pipeline. This is because lug valves can be easily installed or removed from the system using the threaded lugs.
Wafer Butterfly Valve: Wafer-style valves are generally used in applications with limited space. They are more compact and lighter in weight compared to lug valves, making them suitable for installations where space is a constraint.
Pressure Rating:
Lug Butterfly Valve: Lug-style valves have a higher pressure rating compared to wafer-style valves. The lugs provide additional support and allow the valve to handle higher pressures.
Wafer Butterfly Valve: Wafer-style valves have a lower pressure rating compared to lug-style valves. They are typically suitable for applications with lower pressure requirements.
Face-to-Face Dimensions:
Lug Butterfly Valve: Lug-style valves have a specific face-to-face dimension, which means they have a defined length from one end to the other. This dimension is essential for proper installation in the pipeline.
Wafer Butterfly Valve: Wafer-style valves have a shorter face-to-face dimension compared to lug-style valves. This compact design makes them a preferred choice in tight spaces.
In summary, the main difference between a lug butterfly valve and a wafer butterfly valve lies in their design, installation method, pressure rating, and face-to-face dimensions. The choice between the two types depends on the specific requirements of the application, available space, and pressure conditions.
