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Why are more and more piston actuators used in pneumatic valves

Update:23-06-2020
Summary:

1. Why does the desalination medium use rubber-lined bu […]

1. Why does the desalination medium use rubber-lined butterfly valve and fluorine-lined diaphragm valve have a short service life?

 

Demineralized water contains low concentrations of acids or alkalis, which are highly corrosive to rubber. The corrosion of rubber is manifested as swelling, aging, low strength, and the use effect of rubber-lined butterfly valves and diaphragm valves is poor. The essence is that the rubber is not resistant to corrosion. The rubber-lined diaphragm valve is improved to a fluorine-lined diaphragm valve with good corrosion resistance, but the diaphragm of the fluorine-lined diaphragm valve cannot be folded up and down and is broken, causing mechanical damage and shortening the life of the valve. Now the best way is to use water treatment special ball valve, it can be used for 5 to 8 years.

 

2. Why should a hard seal be used for the shut-off valve?

 

The cut-off valve requires the lower the leakage, the better. The leakage of the soft-seal valve is the lowest. The cut-off effect is of course good, but it is not wear-resistant and has poor reliability. Judging from the double standards of small leakage and reliable sealing, cutting off soft seals is not as good as cutting off hard seals. For example, full-function ultra-light regulating valve, sealed and piled with wear-resistant alloy protection, high reliability, leakage rate of 10-7, has been able to meet the requirements of the cut-off valve.

 

3. Why didn't the sleeve valve replace the single and double seat valve?

 

Sleeve valves, which came out in the 1960s, were widely used at home and abroad in the 1970s. In the petrochemical installations introduced in the 1980s, a large proportion of sleeve valves accounted for. At that time, many people believed that sleeve valves could replace single and double seat valves. And become the second generation product. Until now, this is not the case. Single-seat valves, double-seat valves, and sleeve valves have all been used equally. This is because the sleeve valve only improves the throttle form, stability and maintenance is better than the single seat valve, but its weight, anti-blocking and leakage indicators are consistent with single and double seat valves. How can it replace single and double seat valves? What? Therefore, they can only be used together.

 

4. Why is selection more important than calculation?

 

Comparing calculation and model selection, model selection is much more important and complicated. Because the calculation is just a simple formula calculation, it does not lie in the accuracy of the formula, but in the accuracy of the given process parameters.

 

5. Why are more and more piston actuators used in pneumatic valves?

 

For pneumatic valves, the piston actuator can make full use of the air source pressure, making the size of the actuator smaller and more thrust than the membrane type, and the O-ring in the piston is also more reliable than the membrane, so its use will become more and more many

 

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