外选择蝶阀时所考虑的因素

蝶阀在使用10,000次以上，仍然能够保证关闭时“不透气”。

　　butterfly valves can operate for

more than 10,000 cycles and still provide "bubble tight" shut off.

压降 pressure dr-op　　

如果压降太大，会增加能量消耗。但是，应该知道的是，阀门并不是管道系统产生压降的*因素，导致压降的产生还有下列因素。

管道的流体截面。

管道内壁的摩擦力。

通过部件时流向的改变。

蝶阀的流体特性相当于截止阀的三倍甚至更，相当于同样尺寸的闸阀的75%.

energy costs go up with excessive pressure dr-op. point to keep in mind–the valve or valves are but one factor in a piping system

that contribute to pressure dr-op. 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

approximay 75% of an equivalent size gate valve.

通用性 versatility　　

蝶阀通过开启／关闭和节流／平衡来对管道系统进行控制和调节。与闸阀或截止阀相比，蝶阀有更的“通用性”。由于蝶阀能够采用各种表面处理技术和选择弹性材料管道，所以蝶阀有*的化学防腐性能。

　　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.

重量 weight　　

轻型蝶阀的安装费用比重型铸铁阀门节省的多：例如，一个公称通径10英寸的蝶阀重 55磅，而一个10英寸的铸铁闸阀重量就达490磅。对于整个管道系统来说，采用蝶阀所节省下来的安装费用就非常可观。此外，管道系统越重，就要求管道支撑基座要坚固，因此导致整个管道系统更加昂贵。所以，考虑到阀门的重量，就能够节约整个管道系统的成本。

　　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.

尺寸大小 physical size　　

蝶阀所占的空间大约是同等尺寸闸阀的1/6。而每增加一立方英尺的建筑物空间，就意味着成本的浪费。

例如：公称通径10英寸的蝶阀大约是21英寸，而公称通径10英寸的闸阀则达43英寸。

　　butterfly valves take up approximay 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

气密性关闭 bubble tight shut-off　　

闸阀和截止阀（金属与金属连接）的阀座不备不透气关闭的性能。gate and globe （metal to metal） seats cannot provide bubble tight shut-off.

resilient seated butterfly valves are bubble tight by design.

操作简便 ease of operation　　

蝶阀从开启到关闭只需要旋转1/4转（90o）。而闸阀和截止阀需要旋转很多转才能将阀门从开启状态转变为关闭状态。开启或关闭简便易行意味着不需要雇用工资太的操作人员来操作蝶阀。

　　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.

成本 cost　　

一个蝶阀的成本通常只有铸铁闸阀的40%，不但购买成本低，而且安装成本也比较低。

　　a butterfly valve is generally 40% the cost of an iron gate.

not only low initial cost but low installation costs also.

维护保养 maintenance　　

由于蝶阀有很的六体系数和性能很的弹性阀座，因此蝶阀有自动清洗功能，降低了管道被拉鸡杂物堵塞的可能性。

　　properly installed butterfly valves are virtually self cleaning and

are less susceptible to failure due to trash material in the line.