The difference between globe valve and butterfly valve
Globe valve and butterfly valve are two common valves used to control the flow in the pipeline. The disc of the globe valve moves in a straight line along the centerline of the seat to open and close the valve. The stem axis of the globe valve is perpendicular to the sealing surface of the valve seat, and the opening or closing travel of the stem is relatively short, making this valve very suitable for cutting off or adjusting and throttling as the flow.
Butterfly valve’s plate-shaped disc rotates around its own axis in the body to cut and throttle the flow. The butterfly valve is characterized by its simple structure, small volume, lightweight, the composition of only a few parts, and rapid opening and closing by rotation of only 90°, fast control of fluid media, which can be used for media with suspended solid particles or powdery media. Here we’ll discuss the difference between them, if interested, please read on.
- Different structure. The globe valve is composed of the seat, disc, stem, bonnet, handwheel, packing gland, and etc. Once opening, there is no contact between the valve seat and the sealing surface of the disc. The butterfly valve is mainly composed of valve body, stem, butterfly plate and sealing ring. The valve body is the cylindrical, short axial length, it’s open and close is usually less than 90°, when in fully open, it offers a small flow resistance. Butterfly valve and butterfly rod do not have self-locking ability. For the consideration of butterfly plate, a worm gear reducer should be installed on the valve stem. Which can make butterfly plate have self-locking ability to stop butterfly plate in any position and improve the operational performance of valve.
- It works differently. The globe valve raises the stem when it opens or closes, meaning that the handwheel rotates and lifts along with the stem. For butterfly valve, disc-shaped butterfly plate in the body around its own axis rotation, so as to achieve the purpose of opening and closing or adjustment. The butterfly plate is driven by the valve stem. If it rotates more than 90°, it can be opened and closed once. The flow of medium can be controlled by changing the deflection Angle of the butterfly plate. When opened in the range of about 15°~70°, and sensitive flow control, so in the field of large-diameter adjustment, butterfly valve applications are very common.
- Different functions. Globe valve can be used for cutting off and flow regulation. A butterfly valve is suitable for flow regulation, generally in throttling, adjustment control and mud medium, short structure length, fast opening and closing speed (1/4 Cr). The pressure loss of the butterfly valve in the pipe is relatively large, about three times that of gate valve. Therefore, when selecting a butterfly valve, the influence of pressure loss of the pipeline system should be fully considered, and the strength of the butterfly plate bearing pipeline medium pressure should also be considered when closing. In addition, consideration must be given to the operating temperature limitations of the resilient seat material at high temperatures.
- The industrial butterfly valve is usually a large diameter valve used for high-temperature medium smoke duct and gas pipeline. The small valve structure length and overall height, fast opening and closing speed, making it has a good fluid control. When the butterfly valve is required to control the flow of use, the most important thing is to choose the right specifications and types of butterfly valve, so that it can be appropriate, effective work.
In general, a globe valve is mainly used for the open/close and flow regulation of small diameter pipe (branch pipe) or pipe end, the butterfly valve is used for open and close and flow regulation of branch pipe. Arrange by switch difficulty: stop valve > butterfly valve; Arranged by resistance: globe valve > butterfly valve; by sealing performance: globe valve > butterfly valve and gate valve; By price: globe valve > butterfly valve (except special butterfly valve).
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