Factors to Consider When Choosing Butterfly Valves

Operating Life butterfly valves can operate for more than 10,000 cycles and still provide “bubble tight” shut off.
Pressure Drop Energy costs go up with excessive pressure drop. Point to keep in mind–the valve or valves are but one factor in a piping system that contribute to pressure drop. Of equal concern are these factors:

  • Flow area of piping.
  • Friction loss against pipe walls.
  • Change of flow direction via fittings.

  butterfly valves have flow characteristics three times better than globe valves and approximately 75% of an equivalent size gate valve.

Versatility Butterfly valves can be used for on/off service and throttling/balancing. They are superior in “versatility” as compared to a gate or globe valve. Butterfly valves have a wider range of chemical resistance due to the trim options and choice of elastomeric liners.
Weight Installation dollars saved with lightweight butterfly valves as compared to heavyweight cast iron valves; i.e. a 10″ butterfly may weigh 55 pounds, whereas a 10″ iron gate may weigh 490 pounds. This can be an important savings when it is calculated over an entire system. The heavier the system, the stronger the pipe hangers, and the more expensive they become. So by considering the weight of a valve one can also reduce piping system costs.
Physical Size Butterfly valves take up approximately 1/6 the space of a gate valve. Every cubic foot of a building costs money.
I.E.: 10″ butterfly is about 21″ high
10″ iron gate is about 43″ high
Bubble Tight Shut-Off Gate and globe (metal to metal) seats cannot provide bubble tight shut-off.
Resilient seated butterfly valves are bubble tight by design.
Ease of Operation Butterfly valves offer 1/4 turn (90o) open to close. Gates and globes require multiple turns to open and close. Ease of opening or closing means that butterfly valves can employ less expensive operators.
Cost A butterfly valve is generally 40% the cost of an iron gate. Not only low initial cost but low installation costs also.
Maintenance Properly installed butterfly valves are virtually self cleaning and are less susceptible to failure due to trash material in the line.

Posted by Ningbo Valve Factory – China valve manufacturer & Supplier.

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