Thanks to all of you who are sending in great questions including these today:
Q: Do rehabilitated liquid cylinder vacuums last as long as the vacuums on new cylinders? I have some rehabilitated cylinders that have been in service 3-5 years, and have a bad vacuum. I know there are a lot of variables, mostly cylinder handling.
A: You are right. There are a lot of variables. It is actually possible for a rehab vacuum to be better than new depending on the quality of the original vessel manufacturing and first vacuum pull. Heating, time and vacuum pump strength make huge differences in performance. Generally, though, rehabs are done on older vessels so they will be less pristine after rehab than when brand new. They might also have experienced damage, corrosion and introduction of moisture into the annulus. All these factors can affect long-term performance and reinforce the importance of both manufacturing and service quality and process integrity.
Q: I also noticed that, after rehab, there are some welded patches on the cylinders. Do these patched areas cause some new leaks just because a patch cannot be as good as solid material?
A: If the welds are done properly they should not be a new source of leaks (with “properly” being the key word). Leaks are more frequently the results of damage, corrosion or bad metal integrity.
Q: Do rehabilitated liquid cylinder vacuums last as long as the vacuums on new cylinders? I have some rehabilitated cylinders that have been in service 3-5 years, and have a bad vacuum. I know there are a lot of variables, mostly cylinder handling.
A: You are right. There are a lot of variables. It is actually possible for a rehab vacuum to be better than new depending on the quality of the original vessel manufacturing and first vacuum pull. Heating, time and vacuum pump strength make huge differences in performance. Generally, though, rehabs are done on older vessels so they will be less pristine after rehab than when brand new. They might also have experienced damage, corrosion and introduction of moisture into the annulus. All these factors can affect long-term performance and reinforce the importance of both manufacturing and service quality and process integrity.
Q: I also noticed that, after rehab, there are some welded patches on the cylinders. Do these patched areas cause some new leaks just because a patch cannot be as good as solid material?
A: If the welds are done properly they should not be a new source of leaks (with “properly” being the key word). Leaks are more frequently the results of damage, corrosion or bad metal integrity.
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