How to determine valve packing size
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Knowing the valve size and pressure, how can one determine the size of the valve stem packing? Are there any standards? It cannot be disassembled to inspect while in operation
Measure the outer diameter of the packing gland and the outer diameter of the valve stem
I want to know if there are any standards and specifications for valve stems, gland rings, etc., during the design and manufacturing of valves
The valve packing was replaced before, and even for valves of the same pressure rating and size, there are still differences among products manufactured by different manufacturers
Different manufacturers use different sizes; there is currently no unified **standard**
It’s not necessarily the case either; while it is possible to measure the outer diameter of the packing using the outer diameter of the gland, measuring the inner diameter by using the outer diameter of the valve stem may not be accurate. The upper part of some valve stems is slightly smaller by a few millimeters. For valves with multiple degrees of rotation, it is possible to measure the outer diameter of the valve stem, but this method may not be accurate for valves with limited degrees of rotation, such as ball valves
The filler is not manufactured in accordance with any standards; different valve manufacturers produce it in varying ways. It’s necessary to measure it actually, and it’s best to purchase it while bringing a sample along
It’s more or less the same! The right thing to do is to ask your valve suppliers! If you want the filler size, then measure the valve stem size! It generally doesn’t vary much. If that doesn’t work, buy some rope and cut it to use on your own!
Annotations should be visible on the valve drawings; additionally, based on experience, the diameter of the valve stem can be measured to estimate the gap between the stuffing box and the valve stem, and a packing with a thickness slightly greater than this gap can be selected
The outer diameter of the filler can indeed be used to measure the outer diameter of the gland, but using the inner diameter to measure the outer diameter of the valve stem is not necessarily accurate; the top part of some valve stems is slightly a few millimeters smaller
The right thing to do is to ask your valve suppliers!