What kind of butterfly valve is better to choose?
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My unit is building a caustic soda plant. The design department said to use butterfly valves, which are low-priced and light in weight. The liquid alkali storage tank is 10 meters high (concentration 30% or 50%), and the pump uses a stainless steel pump with a lift of 20 meters (clear water). The temperature can reach up to 60 degrees. Which butterfly valve is better to use? , is it hard-sealed or soft-sealed, is it a central butterfly valve/single eccentric butterfly valve/double eccentric butterfly valve/triple eccentric butterfly valve. In addition, the storage tank is DN200, others are DN150, and DN125. The price is not expensive. Please give me some advice!
In this case, you can choose DTD71F-10P, a wafer-type stainless steel butterfly valve made of 1Cr18Ni9Ti. However, for high-concentration liquid alkali of DN200 and below, if the installation space allows, it is better to use a stop valve, which is relatively safer and less likely to leak. This post was last edited by yzdjh on 2009-2-7 15:55 ]
What pipeline are you using the butterfly valve on? And what is the purpose of the pump? Although it is cheap to use a butterfly valve, can it meet the requirements of the process?
Using PTFE lining can also prevent corrosion, but the sealing performance of the butterfly valve is not very good, so be careful of leakage.
The disadvantage of butterfly valves is that the sealing is not too tight. For small-diameter valves, it is recommended to choose gate valves. Butterfly valves are more used on large-diameter pipelines.
I still advise you not to use butterfly valves. The quality of domestic butterfly valves is not good, and the switch stroke is long. There are basically no butterfly valves at the bottom of the storage tank or at the inlet and outlet of the pump. Don't waste the entire tank of material for a small amount of money! !
In terms of sealing performance, gate valves below DN200 have superior sealing performance and last a long time.； Since the direction of the arrow on the butterfly valve is the pressure-bearing direction in professional terms, if the reverse pressure is greater than the forward pressure, internal leakage will occur, which may cause an accident. In addition, the sealing surface of the butterfly valve is easily corroded, causing internal leakage. ； Therefore, it is most ideal to choose a gate valve! :loveliness:
It is not recommended to use butterfly valves. We generally use butterfly valves only on circulating water pipelines or harmless medium pipelines, and the pipe diameter is larger than DN200.
At least use double-coated ones with soft seats (ptfe). I don’t know what your domestic manufacturing level is like for triple-coated ones. There is a Jetstream in Taiwan that makes pretty good ones, and they seem to sell them in mainland China. As you can see, the leakage of triple-coated ones is very low. It looks like a class V.
For large diameters, it is recommended to choose a triple eccentric elastic metal seal butterfly valve with torque sealing, which can achieve two-way sealing and leakage up to VI. Imported products are more reliable.