How do I choose a butterfly valve?
Factors to Consider When Choosing Butterfly Valves
- Wafer lug or grooved end connections.
- Press-to-connect ends selection.
- Broad range of sizes.
- Lug or wafer types.
- Ductile iron, cast iron, CPVC materials.
- Lead-free* selection.
- Fire protection selection.
- High performance selection.
What is the purpose of a butterfly valve?
Butterfly valves are used where space is limited. 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.
How does a butterfly valve work?
Butterfly valves are among the family of quarter-turn valves and work very similar to ball valves. The “butterfly” is a disk connected to a rod. It closes when the rod rotates the disc by a quarter turn to a position perpendicular to the flow direction (right image in Figure 1).
What is the flow characteristic of a butterfly valve?
Butterfly valves inherently have a linear characteristic and in most applications have a useable controllable range between 25 percent and 50 percent of valve travel. They generally have a very high gain at low travel, which means that for a very small change in input signal there is a very large change in output.
What is the difference between ball valve and butterfly valve?
Butterfly valves do not seal as completely as ball valves and are rarely used to control gas flows. Ball valves provide a reliable seal. In high pressure applications, the ball valve will provide superior cut-off characteristics as well as having no trouble turning or needing a pressure-balancing scheme.
What is butterfly valve not suitable for?
Butterfly valves do have limitations that make them unsuitable for flow control in some applications. These include a limited pressure drop capability compared to globe ball valves with greater potential for cavitation or flashing.
Where we can use butterfly valve?
Butterfly valves are used for applications that require handling large volume capacities. It can be used for flow control and regulation and on/off service. Recent developments have permitted this type of valve to throttle more accurately and perform well in high-temperature and high-pressure applications.
What are the 3 most common control valve flow characteristics?
There are three most common control valve characteristics viz Linear, Equal % and Quick-Opening.
Are butterfly valves good for control?
Butterfly valves are a great (and less expensive) alternative to globe and other control valves in applications where 1-2% accuracy is acceptable. If pressures and temperatures are not extreme, this type of valve should work just fine.
How and why butterfly valves are used?
A Butterfly valve is a quarter-turn rotational motion valve, that is used to stop, regulate, and start flow . A butterfly valve has a disc which is mounted on a rotating shaft. When the butterfly valve is fully closed, the disk completely blocks the line.
What is a double offset butterfly valve?
Double Offset butterfly valves are also known as high performance butterfly valves. The ‘Double Offset’ refers to the position of the shaft within the valve, and therefore the opening and closing action of the disc. The shaft slightly moved back from the centreline of the valve, and also out of the centreline…
What is a split-body butterfly valve?
The Sterisplit is a split butterfly valve or high-regulation valve intended to move powders safely in sterile or potentially dangerous applications. Split butterfly valves consist of two parts; the active half and the passive half. Generally, the active half will be mated to the receiving vessel or process machine, with the passive half commonly mounted to the discharging drum or similar.
Why is a butterfly valve?
A butterfly valve is a quarter-turn valve used to regulate flow . A metal disc in the body of the valve is positioned perpendicular to the flow in the closed position, and rotated one quarter of a turn to be parallel to the flow in the fully opened position.