For years, I have seen air blow check valves used on sanitary process lines, across many applications. They provide a very useful and sometimes necessary service: allowing a gas purge of process lines.
However, they are also one of the most unsanitary devices allowed on a sanitary process line. There is no 3-A guideline or standard for them. If you don’t believe me, go find an air blow check valve with a 3-A logo stamped on the side. Or better yet, look in the 3-A standards. These standards address the quality of the air and the filtration of the air prior to the check valve, yet the check valve itself has no standard.
How do you clean your air blow check valve? Do you take it out of place and hand-clean it during every cleaning? There is no practical way to clean it in place. When was the last time someone even looked inside all of your air blow valves? If it hasn’t been done in a while, you’ll be frightened by what you find.
Maybe it’s just one of those things we live with—out of sight, out of mind. But the fact remains: we spend thousands of dollars to get our process systems properly clean. Then we blow clean air through a valve (whose internals would probably qualify for a biology experiment) directly onto our product contact surfaces. Don’t believe me? Go swab test your existing air blow valves, particularly the internal springs and valve seat.
So am I saying we have a catastrophic infestation of bacteria-filled air blow check valves throughout the entire food processing industry, and we must ban them all immediately?
No. Obviously it’s not that bad. Nowhere close, I hope.
We don’t need to stop using air blow valves; they are very useful. And they’ll probably be used more with people trying to conserve water and decrease waste. What we do need to do is be conscious of how they are being cleaned and inspected. We need to be aware that they can be a sanitation concern. They could also be contributing to other issues, like decreased shelf life and other quality concerns. We need to be sure they are part of our cleaning process and are inspected regularly.
Maybe someday there will be a device that does the same job as well and is able to be cleaned in place. Until then, we will have to live in harmony with our dirty little “sanitary” air blow check valves.
