Valve caps missing

A word of caution When the valves are exposed to a corrosive environment, it is likely that their constant movement will induce fatigue stresses, which frequently lead to the rapid deterioration of the retaining lugs and valve caps. It is not unusual to find valves missing in that part of the column where corrosive constituents are concentrated. 

Not sure exactly what he should do, he muscles the container back onto the dolly and continues on. When Steve gets to the spot where he is to leave the cylinder, he notices that the protective valve cap is missing. 

I tend to ignore a few missing valve caps, unless many of the caps are missing in a localized area or the percent of missing caps exceeds 5 to 10 percent. The caps serve very little function as the open area underneath the cap is about the same as the hole area covered by the cap. 

In the first scheme, see Fig. 1 taken from [2], after washing and after eliminating the ferrous contaminants, an aluminium detector separates the bottles from aluminium while the next detector separates the PVC bottles. Further detectors separate the colored PET and the remaining PVC. In general, more detectors for PVC are needed in order to obtain a PVC-free PET (less than 50 ppm). In the second scheme. Fig. 2, the first two detectors separate PVC and the others tiie bottles of colored and transparent PET. Because the aluminium is being progressively substituted by polymers for the cap valves, the aluminiiun detector is missing. 

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