What is double offset butterfly valve?

Double offset butterfly valve is popularly known as a high-performance butterfly valve and has two offsets from the valve body’s center: The shaft axis is offset from the disc’s seat and body seal’s centerline, and. The shaft axis is eccentric to the pipeline’s/valve’s center line.

What type of valve is a butterfly valve?

A butterfly valve is a type of quarter-turn valve that controls the flow of a product in a pipeline. From pharmaceuticals to manufacturing and food processing, the valve has a variety of applications and can be used to limit solid, liquid, or gas material flow.

Is Double offset butterfly valve bidirectional?

Double offset and triple offset butterfly valves are also bidirectional but with preferred flow (pressure) direction, such as flow from the stem side.

What is single offset butterfly valve?

A single offset butterfly valve is designed to resolve the squeezing complication among the disc and seat parts. The axle center of the valve stem is deviated from the focal point of the disc, effecting the bottom and top part of the disc as it is no longer the center of the revolving axle.

What is a double eccentric butterfly valve?

Double eccentric butterfly valves are most often used in water supply applications below ground as an alternative to gate valves. When installing butterfly valves below ground a lower bury depth is required and typically, they are more cost-effective, especially in the large dimensions, compared to gate valves.

What is high performance butterfly valve?

What is a High Performance or Double Offset Butterfly Valve? High Performance Butterfly Valves use a disc offset from the seat center, hence the name Double Offset. In this configuration, the disc is eccentric, or offset, from the valve seat.

What is the difference between unidirectional and bidirectional valve?

In a unidirectional valve the medium can flow in only one direction. In a bidirectional valve, the medium can flow in both the directions.

What is valve offset?

This valve has two stems offset from the center. This creates a cam action during the application’s process. 1st offset: The axis of the shaft is behind the centerline of the sealing point of the disc to seat. 2nd offset: The axis of the shaft is eccentric to the center of the valve/pipe line.

Why use a high performance butterfly valve?

High performance butterfly valves can be used for shutoff and throttling control. They are designed to handle everything from general applications to viscous and corrosive liquids; corrosive gases and steam.

Are butterfly valves reliable?

Butterfly valves are very precise, which makes them advantageous in industrial applications. They are quite reliable and require very little maintenance.

Does flow direction matter in butterfly valve?

The butterfly valves are bi-directional but do have a preferred flow direction. It’s however strongly recommended to install the valves in the preferred flow direction, as it will extend the valve’s life span and will also lower the operating torque.

What is bidirectional butterfly valve?

Enable a bubble-tight seal with fully bidirectional, zero-leakage shutoff. According to the British Valve and Actuator Association, a butterfly valve is “a valve in which the obturator rotates about an axis at right angles to the direction of flow, and in the open position, flow passes around the obturator.”

Are butterfly valves bidirectional?

How do you service a butterfly valve?

Make sure there is no welding residue, waste, rust or other debris in the pipe before installation. Wash with water or a mild detergent if needed. Clean the surface of the flange that will come in contact with the butterfly valve to ensure it is free of rust and debris. Wash with water or a mild detergent if needed.

When should you not use a butterfly valve?

4 Reasons Not To Use Butterfly Valve When Handling Dry Material

• Not Designed for Dry Material. Butterfly valves are not designed to handle dry bulk solids.
• Disk Impedes Material Flow Stream.
• Difficulty Displacing Dry Materials.
• Soft Seals are Exposed to Material.

Can you control flow with a butterfly valve?

Unlike gate valves, butterfly valves can be used for throttling or regulating flow as well as in the full open and fully closed position. The pressure loss through a butterfly valve is small in comparison with the gate valve.

Which way do you install a butterfly valve?

API butterfly valves are bi-directional and may be installed with flow in either direction, vertically, or horizontally. If a choice of stem position exists, the valve should be installed with the stem in the horizontal position; this will minimize seat wear by distributing the stem and disc weight evenly.