Must the lower surface of the handwheel be in tight contact when the stop valve is fully closed?
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Must the handwheel reach the position shown when the stop valve is fully closed, with a tight fit? How can the valve opening degree be determined from the height of this section of thread that has been unscrewed?
Not necessarily. Without impurities, they won’t fit tightly together.
Generally, when it can no longer be turned, that means it is tightened
That’s not necessarily the case; some distances are not close at all. We usually use saw blades to mark the scales.
It’s just a pity that when designed and used in this way, the valve core and seat of the stop valve are very prone to excessive wear due to interlocking.
Which design is sad? Is it fully closed when it fits tightly? It’s designed so that everything is fully shut off to prevent accidental operations that could cause wear, right?
When the valve is fully open, is it fully open when the two surfaces indicated by the purple arrows in the diagram are in contact?
If it fits tightly, it’s an unreasonable design; space must be left.
Stop valves are used for shutting off flow, not for regulation; they are operated in either fully open or fully closed position, until they can no longer be turned.
It can be said that no precise adjustment is required. There is still some rough adjustment capability
Strictly speaking, shut-off valves of this type must not be used for regulating purposes; firstly, the regulation accuracy is poor and thus of little use, secondly, it reduces the valve’s lifespan, and most importantly, using it for regulation can lead to a failure in the back sealing of the valve stem, posing a safety risk. Feel free to point out errors and share your thoughts.