國外選擇蝶閥時所考慮的因素

使用壽命 Operating Life　　

蝶閥在使用10,000次以上，仍然能夠保證關閉時“不透氣”。


　　Butterfly valves can operate for


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


壓降 Pressure Drop　　


如果壓降太大，會增加能量消耗。但是，應該知道的是，閥門并不是管道系統產生壓降的唯一因素，導致壓降的產生還有下列因素。


管道的流體截面。


管道內壁的摩擦力。


通過部件時流向的改變。


　　


蝶閥的流體特性相當于截止閥的三倍甚至更高，相當于同樣尺寸的閘閥的75%.


　　


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.


通用性 Versatility　　


蝶閥通過開啟／關閉和節流／平衡來對管道系統進行控制和調節。與閘閥或截止閥相比，蝶閥具有更好的“通用性”。由于蝶閥能夠采用各種表面處理技術和選擇彈性材料管道，所以蝶閥具有極強的化學防腐性能。


　　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　　


輕型蝶閥的安裝費用比重型鑄鐵閥門節省的多：例如，一個公稱通徑10英寸的蝶閥重55磅，而一個10英寸的鑄鐵閘閥重量就高達490磅。對于整個管道系統來說，采用蝶閥所節省下來的安裝費用就非常可觀。此外，管道系統越重，就要求管道支撐基座要堅固，因此導致整個管道系統更加昂貴。所以，考慮到閥門的重量，就能夠節約整個管道系統的成本。


　　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　　


蝶閥所占的空間大約是同等尺寸閘閥的1/6。而每增加一立方英尺的建筑物空間，就意味著成本的浪費。


　　


例如：公稱通徑10英寸的蝶閥大約是21英寸高，而公稱通徑10英寸的閘閥則高達43英寸。


　　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


氣密性關閉 Bubble Tight Shut-Off　　


閘閥和截止閥（金屬與金屬連接）的閥座不具備不透氣關閉的性能。Gate and globe (metal to metal) seats cannot provide bubble tight shut-off.


Resilient seated butterfly valves are bubble tight by design.


操作簡便 Ease of Operation　　


蝶閥從開啟到關閉只需要旋轉1/4轉（90o）。而閘閥和截止閥需要旋轉很多轉才能將閥門從開啟狀態轉變為關閉狀態。開啟或關閉簡便易行意味著不需要雇用工資太高的操作人員來操作蝶閥。


　　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　　


一個蝶閥的成本通常只有鑄鐵閘閥的40%，不但購買成本低，而且安裝成本也比較低。


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


Not only low initial cost but low installation costs also.


維護保養 Maintenance　　


由于蝶閥具有很高的六體系數和性能很好的彈性閥座，因此蝶閥具有自動清洗功能，降低了管道被拉雞雜物堵塞的可能性。


　　Properly installed butterfly valves are virtually self cleaning and


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