Compressed Gas Sampling- Particle Velocity

A big question we get about air sampling compressed air is how to perform it appropriately. First, it is crucial to ensure that the gasses used in your manufacturing processes are not contaminating your product. Two factors you need to control when monitoring compressed gasses, velocity, and volume.  Ensuring these you managed these two factors, you will acquire the desired result from sampling.

First, let’s explain particle velocity, monitoring for viable and non-viable particles; the particle velocity can impact your sample in different ways. The non-viable particle counters use an electrical response to calculate particle size; this is a function of flow and area to get a controlled velocity. If particles flow much faster through the sensor, they will read a much smaller particle size than the particle. The quicker speed will cause the undesired result of having larger particles in your compressed gas, and you are unaware. For the viable particle counter,  the impact velocity of your particle to your media is your primary concern. Higher speeds may kill your organism upon impact to your agar plate, hence not having the desired recovery from your monitoring.

The problems generated from velocity cause the worst-case scenario, not finding the contamination in the source and finding it later in your product testing. This contamination will cause two undesired situations: the waste of your product and the cost of the investigation to determine where the contamination is occurring in your process. These problems come with a price that labs can significantly avoid.

Compressed Gas Sampling- Sample Volume

Now let’s talk about volume; when rushing the compressed gas through your Viable or Non-Viable particle counter, you have no flow control. No control of flow impacts your sample volume; both standards for monitoring require a specific sample volume so you can determine you’re allowable of particles per volume. Though not so critical, as it is oversampling, the real issue is your sample media for your Viable Sampling. Blasting your media with a compressed gas will cause the media to dry up, therefore not being viable for growth; this will cause an issue.

To get to what’s important, how is this fixed? It is simple; you use a diffuser! The CI-302 diffuser is designed for operation at different pressure levels according to your flow rate; we can ensure you get the right one using tables that have it all pre-defined. This way, the sample is taken from the compressed gas and not the compressed gas shot into your sampler. With the diffuser, your air sampler will extract the required gas, and the rest will be shot out through waste gates, guaranteeing your velocity and sample size control. If any investigation happens, further along, you will have the guarantee that your air sampling process is under control!-