Common problems in the operation of sanitary valves

1. Why does the desalted water medium use a sanitary-grade valve with a rubber-lined butterfly valve and a fluorine-lined barrier valve with a short service life?
    Demineralized media contain low concentrations of acids or bases which are highly corrosive to rubber. The corrosion of the sanitary valve rubber is characterized by shrinkage, aging and low strength. The butterfly valve and the barrier valve with rubber lining have poor application effect, and the essence is that the rubber is not resistant to corrosion. The backing rubber spacer valve is improved to a fluorine-resistant barrier valve with good corrosion resistance, but the diaphragm of the fluorine-lined barrier valve can be broken by being folded up and down to form a mechanical damage, and the life of the valve is shortened. The best way to do this today is to dispose of the special ball valve with water, which can be used for 5 to 8 years.

Why can't double seal valves in sanitary valves be used as shut-off valves?
    The advantage of the double seat valve spool is the force equalization configuration, which allows a large differential pressure, and its outstanding drawback is that the two sealing surfaces cannot be in good contact at the same time, resulting in a large leakage. If it is used artificially and compulsibly for cutting off the site, it is obviously not effective, even if it has made many improvements (such as double-sealed sleeve valves), it is not advisable.

    2. What is the poor anti-blocking performance of the straight stroke regulating valve, and the anti-blocking performance of the angular stroke valve in the sanitary valve?
    The straight-stroke valve spool is vertically throttled, and the medium flows in and out. The flow passage in the valve chamber must turn and turn, making the flow path of the valve quite complicated (the shape is inverted "S" type). Thus, there are many dead zones that provide space for the precipitation of the medium, and over time, infarction. The direction of the angular stroke valve throttling is the degree direction. The degree of the medium flows in, the degree flows out, and the unclean medium is easily taken away. At the same time, the flow path is simple, and the space for the medium to precipitate is also small, so the anti-blocking performance of the angular stroke valve is good.
    3. Why is the valve stem of the straight stroke regulating valve in the sanitary valve relatively thin?
    It touches on a simple mechanical principle: large sliding friction and low rolling friction. The valve stem of the straight stroke valve moves up and down, and the packing is slightly pressed tightly, which will tightly seal the valve stem and produce a large backlash. For this reason, the valve stem is designed to be very small, and the filler is also commonly used with a small friction coefficient of PTFE filler to reduce the backlash, but the problem is that the valve stem is thin, the bend is easy, and the filler life is short. The best way to deal with this problem is to use the travel valve stem, that is, the angular stroke type regulating valve. Its valve stem is 2 to 3 times thicker than the straight stroke valve stem, and the graphite packing with long life is selected. Well, the filler has a long service life, and the friction torque is small and the backlash is small.

    4. Why is the cut-off pressure difference of the angular stroke type valve in the sanitary grade valve larger?
    The cut-off pressure difference of the angular stroke type valve is large because the resultant force of the medium on the valve core or the valve plate generates a very small torque to the rotating shaft, and therefore, it can accept a large pressure difference.

    5. Why is the application of the rubber-lined butterfly valve and the lining of the fluorine-blocking valve in the sanitary-grade valve to have a short service life?
    Demineralized media contain low concentrations of acids or bases which are highly corrosive to rubber. The corrosion of rubber is characterized by shrinkage, aging, and low strength. The butterfly valve and the barrier valve with rubber lining have poor application effects, and the essence is that the rubber is not resistant to corrosion. The backing rubber spacer valve is improved to a fluorine-resistant barrier valve with good corrosion resistance, but the diaphragm of the fluorine-lined barrier valve can be broken by being folded up and down to form a mechanical damage, and the life of the valve is shortened. The best way to do this today is to dispose of the special ball valve with water, which can be used for 5 to 8 years.

    6. Why should the shut-off valve in the sanitary valve be as hard as possible?

    Shut-off valve request to leak as low as possible