Offset Butterfly Valves: Uses and Conventions


Offset butterfly valves are able to assist businesses in regulating the flow of process media through their system of pipelines. This type of control is necessary during operational procedures. The amount of process media flowing through a system often needs to be varied according to applications, progress, and in response to other unknown factors that may crop up during the course of operation. Sometimes, flow may need to be halted completely, either for an adjustment, a system repair, or for another type of emergency that may occur. Implementing offset butterfly valves into a pipeline can give businesses the power they need over the media involved in their production processes.

Offset butterfly valves are able to control media flow through the movement of a round disc, which is able to completely block the pipeline when it is in the closed position. The round disc is sized to the pipeline, so that it can reliably shut off and completely seal the passageway when directed. Offset butterfly valves rotate on an axis, so that the disc is always present within the pipeline. When the valve is moved to the open position, the disc is rotated to a position where it is parallel to the pipeline. While the media flowing through at that point will experience a drop in volume pressure due to the presence of the disc, flow will still be permitted on either side of the disc. It takes a quarter of a turn for an offset butterfly valve to move from a completely shut to a completely open position. This allows for quick shutoff to occur, which may be a necessary feature for businesses that require a fast response that will stop flow.

Offset butterfly valves are often implemented in situations where the factory conditions contain a great deal of pressure. Sometimes, offset butterfly valves are also referred to as triply-eccentric valves. They are specially designed with a metal seat, which is able to withstand more pressure than a seat that is composed of rubber or another less durable material. Due to the need for the metal disc to intersect with the metal seat when sealing off the pipeline, offset butterfly valves are designed so that contact between these two metal objects is not achieved until the objects are ready to be in the completely shut position. This design is intended to avoid any scratches or other harm that might arise from two metal objects coming in frequent contact with each other.

Offset butterfly valves are especially beneficial in situations where shutoff is required in more than one direction, or in situations when extrusion might occur. Systems that deal with heavy or dirty oil generally opt for the implementation of an offset butterfly valve. Additionally, systems working with gas and other types of chemicals are typically better served by the more reliable and bi-directional seals that can be created by an offset butterfly valve. Other butterfly valves tend to be lighter weight and less durable, and might not be appropriate for these more industrial conditions.