The steam cut-off valve has a short lifespan
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The company has several reaction kettles, and the steam shut-off valves used to control heating – namely pneumatic O-ring ball valves – have suffered severe internal leakage after two years of use; however, the same type of shut-off valves used in the material pipelines, purchased from the same batch, have not experienced any internal leakage. The globe valves before and after the steam valve also need to be replaced frequently. Generally, the reaction vessel has two internal coils: one for steam (to raise the temperature) and one for circulating water (to lower the temperature). The steam cut-off valve is installed at the inlet of the steam coil. To enhance the cooling effect, a short circuit is created between the two coils; the steam cut-off valve is closed first, after which circulating water is introduced into the steam coil to achieve cooling. I have analyzed that when the circulating water enters the steam coil, it comes into contact with residual steam and vaporizes violently, generating a large number of bubbles that wash against the steam cut-off valve at the front end of the steam coil, damaging its sealing surface and causing severe internal leakage in the valve. I’ve heard that many companies do the same thing; I wonder if there are similar problems as well? How was it solved?
In any case, one thing: the substance entering the valve should contain as little water as possible; it’s best if it’s superheated steam.
This post was last edited by jizhenlin on 2016-11-25 at 17:47. We have also encountered similar problems with our dissolution tanks (which use steam pressure and elevated temperatures for dissolution). The valves supplied by Taiwan’s JinDian, whether they are metal-sealed or soft-sealed ball valves, start to leak after being in use for a while. After analyzing the reason, we found that our dissolution tanks are used intermittently, and the steam is turned off periodically as well. When the steam valves are not in use for an extended period, steam from the dissolution tank flows through the coils into the pipes and back behind the valves. There, the steam condenses into water, and when the steam valves are turned back on again, a water hammer effect occurs, which severely damages the valve seals. Later, check valves were installed behind all the steam pipeline valves to prevent steam from flowing back and condensing into water after the valves were turned off. After this modification, the valve seal problems were completely resolved. For reference
Indeed, intermittent use of steam valves can lead to internal leakage in those valves; installing a check valve on the control valve can prevent such phenomena. Now, all our reboilers that require steam for heating are equipped with check valves.