General basic knowledge of butterfly valves
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I have been working in turbine units for many years, but I didn’t know much about valves. Recently I encountered some problems related to valves, and that’s when I realized I needed to start learning about them. May I ask, when selecting valves, are there flow rate restrictions for various types of valves, and does it not need to match the pipe diameter? 2 Which type of valve has the lowest resistance? What do the flow rate limits of 3 m/s and 5 m/s for 3 butterfly valves mean?
Gate valves are used to shut off fluids; when fully open, the flow path is completely unobstructed, resulting in the lowest pressure loss for the fluid flow.
When the butterfly valve is at a medium opening position, the shape of the opening formed between the valve body and the front end of the butterfly plate is symmetric with respect to the valve shaft; on one side, the front end of the butterfly plate moves in the direction of water flow, while on the other side it moves against the direction of water flow. As a result, one side forms an opening similar to a nozzle, whereas the other side forms an opening similar to a throttle orifice. The flow velocity is much higher on the nozzle side than on the throttle side, and negative pressure is generated below the valve on the throttle side, which often leads to the detachment of the rubber seals.
The butterfly valves in our tank area are breaking down rapidly; domestic ones won’t work.
The flow resistance coefficient ξ of a valve depends on the size, structure, and shape of its internal cavity, among other factors; it can be considered that each element within the valve’s cavity functions as a system that generates resistance (such as fluid turning, expanding, contracting, turning again, etc.). Therefore, the pressure loss within the valve is approximately equal to the sum of the pressure losses of all the components of the valve. Generally, gate valves present low fluid resistance when fully open; different valves serve different functions, so such comparisons are rare.
Hello everyone! Our factory is looking to purchase a batch of switch butterfly valves. Does anyone know which domestic manufacturers produce good quality butterfly valves that can be used as switches on fans? We are interested in ordinary butterfly valves with a diameter of DN250
Tiansheng Valve Group’s butterfly valves are quite well-known in China; the company has offices in Wenzhou and Qingdao, where you can inquire about them.
Studying*. Beijing’s Holi butterfly valves (standard middle-type) are of good quality – really excellent. However, if the quantity ordered is small, they don’t pay much attention to such orders.