国外选择蝶阀时考虑的因素

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　　使用寿命Operating Life　　 蝶阀在使用10,000次以上，仍然能够保证关闭时“不透气”。
) V3 I5 r* [$ r7 X4 K　　Butterfly valves can operate for
% r/ U) O: O% l% \) |  Z　　more than 10,000 cycles and still provide "bubble tight" shut off.
　　压降Pressure Drop　　
　　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唯一因素，导致压降的产生还有下列因素。
1 h# l0 h% N' _& r* b; K5 N, V7 _　　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。
　　
( s4 l) _2 K7 V6 U( k- g5 r　　蝶阀的流体特性相当于截止阀的三倍甚至更高，相当于同样尺寸的闸阀的75%.
1 R  e2 E3 A/ w( T　　
: x% ^* j: p( P; |8 e3 _6 l' C　　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:
, W5 w( F6 D8 l6 A# r; v4 l0 W　　Flow area of piping.
. Y" F# B. Y' m2 m) q( J　　Friction loss against pipe walls.
: v: @+ Y7 k4 I  c$ r# D6 h) R　　Change of flow direction via fittings.
* u9 ]4 `; }" |　　Butterfly valves have flow characteristics
/ Z7 w( }, I6 n　　three times better than globe valves and
: x# Z% J) n  ?! w  {3 V' q　　approximately 75% of an equivalent size gate valve.
6 e. B& j. D* k; O　　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，蝶阀具有更好的“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，所以蝶阀具有极强的化学防腐性能。
* V3 x8 h' G- @- @* p5 @　　Butterfly valves can be used for on/off service and throttling/balancing.
" {7 x1 n6 q+ w# _9 s　　They are superior in“versatility”as compared to a gate or globe valve.
  X, X( m6 i! X  p/ Y) a+ T* }　　Butterfly valves have a wider range of chemical resistance due
- U! W  _! R, ~$ t3 B2 J　　to the trim options and choice of elastomeric liners.
( I* z: F5 p9 Q8 `+ _* Y, x" u5 m　　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高达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。
* ?6 z; y$ J1 W- a& l) e6 M- u　　Installation dollars saved with lightweight
& @# A# g2 M, t" i0 |3 `5 }, C　　butterfly valves as compared to heavyweight cast iron valves;
　　i.e. a 10" butterfly may weigh 55 pounds,
- Q  c4 }) }) {9 w5 F; Z( i- t$ Z0 x　　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,
) f  A8 h" ]6 v) J- c% n　　and the more expensive they become.
) [' F& H' d$ p　　So by considering the weight of a valve one can also reduce piping system costs.
  _+ h* `5 K' b　　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。
# f) T6 P" m9 ~  x. m, N. z　　
　　例如：公称通径10英寸的蝶阀大约是21英寸高，而公称通径10英寸的闸阀则高达43英寸。
) j# L( @/ w- v6 I7 w　　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
　　气密性关闭Bubble Tight Shut-Off　　
+ P( B' \0 H( u/ m/ P　　闸阀和截止阀(金属与金属连接)的阀座不具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　　
* z3 n" W+ A7 @4 D0 J  y# f　　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高的操作人员来操作蝶阀。
　　Butterfly valves offer 1/4 turn (90o) open to close.
; L! q4 m8 i" L! @, y, ?7 k　　Gates and globes require multiple turns to open and close.
6 F& s) [- `) Z; R6 O! |6 V# K5 P　　Ease of opening or closing means that butterfly valves can
# D" \3 L8 l7 \8 s6 Z$ |　　employ less expensive operators.
3 n9 J7 y% j3 w/ j% y3 z+ A　　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。
. j4 G4 i% ~7 u, g5 c$ G2 w　　A butterfly valve is generally 40% the cost of an iron gate.
  `1 h# j! F2 P) S! Q6 Z　　Not only low initial cost but low installation costs also.
　　维护保养Maintenance　　
　　由于蝶阀具有很高的六体系数和性能很好的弹性阀座，因此蝶阀具有自动清洗功能，降低了管道被拉鸡杂物堵塞的可能性。
4 q: ]! q- Y9 L) b　　Properly installed butterfly valves are virtually self cleaning and
6 D& N" v; Z* ^! Q6 h　　are less susceptible to failure due to trash material in the line.
/ R; _, H# Q2 N& |$ g. F6 G文章关键词： 蝶阀