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Why is the service life of purification water
medium short when using rubber lined butterfly valve and fluorine lined
diaphragm valve?
The medium of purification water contains low
concentrations of acid or base, which are pretty eroding to rubber. The
corrosion of rubber is exemplified by growth, aging and low strength. The poor result
of using rubber lined butterfly valve and diaphragm valve is essentially caused
by the narrowness of corrosion of rubber. Rear rubber-lined diaphragm valve is
improved to be the fluorine lined diaphragm valve that has a decent tolerance
of erosion. But the lining of diaphragm of fluorine lined diaphragm valve can't
withstand the up-and-down folding and is broken, resulting in mechanical damage
and shorter service life of the valve. Now the best way is to use water
treatment special ball valves, which can be used for 5 to 8 years. See more: valves design services.
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Why should shut-off valves try to use hard
sealing?
Sanitary shut-off valves require the leakage to be as
low as possible. The leakage of soft sealing valve is the lowest, so the
shut-off effect is certainly good. But it's not wear-resistant, not reliable.
Judging from the double standard of small leakage and reliable sealing, soft
sealing shut-off is not as good as hard sealing shut-off. Take full-featured
ultra-light regulating valve for example, it's sealed and piled with
wear-resistant alloy for protection, highly reliable, has a leakage rate of 10
to 7, all of which already have met the requirements of shut-off valves.
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Why can't sleeve valves replace single-seat and
double-seat valves?
Sleeve valves, which first appeared in the '60s, were
widely used in the '70s worldwide. Sleeve valves account for a large percentage
in petrochemical equipment imported during the '80s. At that time, many people
thought cover valves could replace single-seat and double-seat valves to become
the second-generation products. Until now, that is not the situation.
Single-seat valves, double-seat valves and sleeve valves are equally used.
That's because sleeve valves only improve the way of throttle, have better
stability and maintenance than single-seat valves. But its weight,
anti-blocking and leakage indicator are the same as those of single-seat and
double-seat valves.
·
Why is selection more important than
computation?
Compare computation with selection, selection is more
important and more complicated. Computation is only a simple formula. It's not
the formula itself, but rather the accuracy of given parameters that matters.
Selection involves a lot of things, being a bit careless will lead to improper
selection, which not only results in the waste of manpower, material, and
money, but the effects of use are not good, causing a number of problems in
use, such as reliability, service life and quality, etc.
·
Why is piston actuator increasingly used in
pneumatic valves?
For pneumatic valves, the piston actuator can make
full use of air pressure to make the size of the actuator smaller than that of
the film type. The thrust is bigger. The O-ring in the piston is also more
reliable than that of the film. All in all, it's increasingly used.