I would like to ask what to do if the medium crystallizes; are there any other solutions when selecting valves if insulation jackets are not used?

By the way, would it be better to use a ball valve?

The common method for dealing with crystallization in the medium is to use a jacket or heat tracing.

Either use a jacket or heat tracing, but this only provides temporary relief; the reason is that there are dead corners in the ball valve’s valve core and body, where fluid can remain and easily cause the valve to get clogged. If it is a slurry medium that tends to crystallize, a plug valve is a better choice. Its advantage is that there are no dead corners in the valve body, and metal lips are present at the passage area; these lips can scrape away the crystals as the valve rotates, ensuring long-term use

I agree with what was said on floor 5; I think the same way. If there’s a chance in the future, I’ll give the plug valve a try

Only jacketed valves can be used; we have extensive applications for them in our projects

When the diameter is relatively large and it’s difficult to choose a plug valve, there is another option: angular valves with long stroke that are used as control valves. When these valves are opened, the valve stem moves backward; thus, even if there are crystals on the valve disc and seat, the further movement of the valve stem helps to maintain the Cv value, which in turn extends the interval between cleaning cycles. This applies to the FISHER SS-83 valve

5# majian1944: Using external heat tracing tubes together with thermal paste will resolve issues such as crystallization and blockages.

For 10# shirleymao, if external heating tubes and thermal paste are used to prevent crystallization, I think a jacketed ball valve is a better option – the heat effect is concentrated and uniform, resulting in less loss and a longer service life. However, these two methods are only temporary solutions. As long as it is a ball valve, there will inevitably be dead corners between the ball and the valve body, aside from the area in contact with the valve seat; this is an inherent flaw that cannot be avoided. When residual liquid accumulates in dead corners, crystallization may not occur if there is heat tracing (note that this is just a possibility, as the parameters are unknown; I don’t know either the temperature or conditions under which the medium crystallizes, so it’s possible that crystallization will still occur even with heat tracing). But what if there is no steam or the steam temperature is too low during maintenance or in case of an accident? It will still crystallize! Moreover, if the heat tracing temperature exceeds 180 degrees or even less, PTFE soft-sealed ball valves cannot be used; only metal hard-sealed ones can be employed. However, the sealing performance and corrosion resistance will decrease, while the cost will increase. The principle of a plug valve is similar to that of a ball valve; the difference is that the linearly sealing seat ring is replaced by a PTFE liner that provides 360-degree sealing, and the valve ball is transformed into a plug, resulting in an improved sealing effect. Additionally, there are metal lips at the diameter of the valve body, which help to scrape away any crystalline substances attached to the valve core as it rotates, preventing them from reaching the sealing surface. This solves the crystallization problem while avoiding increased costs for heat tracing. The maximum pressure rating can reach 600 pounds, and the upper temperature limit is 315 degrees Celsius (when using T600 bushings). It perfectly solves the problem of liquid accumulation and crystallization in the dead zones of ball valves.