Seeking answers from experts in valve technology
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Seeking a valve for the following operating conditions: medium: hydrochloric acid, saltwater, with trace cement impurities； Temperature: room temperature, Pressure: 2 kilograms, Switching frequency: 5 times per minute, Normal state ； Diameter: DN50. 1. In terms of medium and switching frequency, PTFE butterfly valves or diaphragm valves may not be the best choice ； 2. Flexible valves were used on site previously, with unsatisfactory results ； 3. If a metal hard-sealed ball valve is used, there is concern regarding corrosion by hydrochloric acid. So, what kind of valve should be used to meet the operational requirements?
This post was last edited by Valve Mingming on 2017-2-15 at 12:38. Use ceramic valves – they are wear-resistant and corrosion-resistant, but of course their price is high, and customers may not be willing to pay that much; often they settle for cheaper alternatives!
Go for cost-effectiveness; would it work to use Hastelloy?
A ceramic ball valve or a fluorinated ball valve will work; they are not expensive.
For Hastelloy, it depends on the quantity, and the price is also high. A casting factory may not be willing to produce the blank for just one unit, unless the lead time is very long and it can be cast along with other valves. It is still recommended to use ceramic ball valves, as they are resistant to wear and corrosion.
Hastelloy is not necessarily effective; it also suffers significant wear due to materials like cement
Taking into account the erosion caused by mud, Hastelloy valves are not necessarily cheaper; ceramic valves with a DN50 size should also not be too expensive
Hydrochloric acid corrosion is generally handled with Hastelloy B, but given the presence of cement impurities, it’s necessary to see whether STL alloy can withstand both corrosion and these impurities. If not, more expensive options such as Inconel alloy or ceramic valves will have to be used.
For such operating conditions, a V-type metal-sealed ball valve is recommended (to eliminate dead zones in the flow of the medium). Regarding corrosion resistance, the concentration and temperature of hydrochloric acid must be provided in order to select the appropriate material； Regarding wear resistance, the valve seat ball can be coated with cemented carbide to address this issue as well.