Sanitary Sampling Valve
Contaminated sample is one of the most common problems in Pharmaceutical and Biotech industries which has been found in both water system and production. In order to avoid or minimize contamination risk, apart from right technique or procedure, is to make a correct valve selection as well as fully understand right installation.
Regarding engineering component, there are questions and concerns of which sampling valve’s features, functions or designs is right for certain usage and application.
Moreover, lots of valve makers, many brands has defined their own product as “sanitary sampling valve” and that could have led to misconception to end-user in Pharmaceutical and Biotech industries just because of how it’s named, how it’s called. Because sometimes those so called “sanitary sampling valve” is not really suitable for all application or usage, then contamination issue has been incurred.
What is important in sanitary sampling valve?
The most important of sampling is that it must be only sample, not any other foreign objects. Poor sampling valve or wrong installation can let foreign matters being formed and come out with sample. It would be 3 main contamination causes.
Incorrect valve selection
- Incorrect valve selection
- Use food-grade valves do not have any surface finish treatment
As microbes are very small and can be trapped into unsmooth surface and that creates contamination risk
- Lack of understanding to use “Y-shaped” sampling valves
This type of valves require operator to sterile outlet before take sampling but most of the times, they have never been sterile before using so that in red circle area are full of germs and that cause contamination.
- Unaware of dead-leg issue
Some valve for some using is impossible to avoid dead-leg issue, no matter what installation techniques. Too much dead space in red highlight is dead area and contamination issue begins
- Incorrect installation
Valve selection itself is not only a problem, but also wrong installation too that can cause contamination regardless to valve quality or valve design. A photo below indicates too much dead-leg in red circle that creates microbe accumulated. (photo also shows wrong valve selection according to 1(b) in blue circle)
- Poor valve design
Assuming that we all make right selection and fully understand how to install, the last factor that can be contamination cause is valve design. However, as there are lots of valve makers and lots of designs in the market, it may be not possible to describe and explain everything here, so that it will be only one comparison example hereunder,
From above picture, we are hardly tell the differences between left valve and right valve by looking from outside, however, considering in details, we can find that;
- Left valve has long flat area, so that when water or liquid goes from right inlet to bottom outlet, it may remain water or liquid droplet stay on that area as shown by red dot.
- Left valve uses O-Ring to seal inlet and mechanical part as shown in blue circles, O-Ring will be forced to move back and forward every time user operates this type of valve, therefore, after a while, O-Ring will be worn and torn and the microbes can be trapped into damage area of O-Ring or part of O-Ring itself could contaminate sampling water or liquid.
Unlike the valve on the right, internal design is short and curved without O-Ring, but using encapsulated seal that smoothly move back and forward when valve is open or closed, so that contamination risk is minimized.
Lastly, outlet length of left-valve is very long which can cause stagnant water inside outlet after valve is already closed. The remaining stagnant could contaminate the next sample.
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