The Monitor

Production Process Insights

Double Validation Meets Regulatory Compliance

Posted by Sentry Equipment on 3/11/15 10:00 AM


Manufacturing and quality control engineers across a variety of industries are faced with the daily challenge of maintaining regulatory compliance using questionable sample analysis results. This is especially true for pharmaceutical and other production environments where industrial waste volumes must be accurately characterized. Standard sampling practices, such as taking a repeatable sample from a good location, are just not enough for complete confidence in these environments.

To meet stringent regulatory requirements using validated methods for industrial waste effluent, field engineers must make extra effort to ensure the composite sample reflects the actual flow of the sample stream. When a sample is used as a composite for a flowing toxic waste stream, the accuracy of the volume as well as repeatability is critical.


This was the challenge for a pharmaceutical company working with a sample stream containing both liquids and solids – slurry – which is a classic application for the Sentry® ISOLOK® SAA automatic fixed volume sampler. For this customer’s particular application:

  • Double validation for each sample was required. However, the ISOLOK SAA sampler annulus and controller signaling the known volume, and indirectly determining the number and frequency of the individual samples, was insufficient to meet this requirement.
  • Direct indication of each sample completion was needed to fully validate the composite sample volume related to effluent flow.
  • The hazardous sample environment required ATEX zone 2 design (similar to NEMA Class I, Division 2).
  • The slurry sample was highly corrosive, necessitating special alloy construction.

To meet the specific application for this pharmaceutical customer, engineers developed a unique design of the ISOLOK SAA automatic fixed volume sampler. Double validation of the sample stroke called for verification of both the extend and retract functions of the sampling process so there was a direct indication of each sampler stroke. This proved to be more complicated than originally indicated. While the standard 316 stainless steel (SS) actuation cylinder had the ability to validate the retract position to assure the sampler probe was out of the line, it did not have the same ability for the extend function.

Typically, this easily could be accomplished with a standard aluminum pneumatic cylinder with external proximity switches replacing the standard 316 SS cylinder. However, aluminum reacts with iron oxide and is highly exothermic, and is not allowed in any ATEX hazardous environment that has the possibility of both rust and aluminum being present.


To overcome this barrier, the ISOLOK SAA sampler was custom designed using a 316 SS sampler actuating cylinder with embedded magnetics, along with external ATEX-approved proximity switches mounted on the cylinder. This had to be designed and built to stay within compact cylinder space tolerances. Wetted parts of the sampler used high nickel alloy C-276, a normal variation for the SAA sampler, and all other metallic components were made using 316 SS for corrosion resistance.

Slurry sampling for direct indication and double validation of sample volume now easily can be achieved with the compact 316SS actuating cylinder operating on any ISOLOK SAA sampler, regardless of materials. In addition, using the validated number of sampler strokes combined with the known sampler annulus volume allows for a statistical analysis of any degradation of the sampling process – from issues such as seal failure, line blockage or erosion of the sample annulus.

Manufacturing engineers seeking complete confidence in their sample analysis of hazardous materials for regulatory compliance know that begins with a reliable, representative sample. The ISOLOK SAA automatic fixed volume sampler provides just that, repeatedly.

Learn more about the ISOLOK SAA automatic fixed volume sampler here.

This article was originally published on our website.

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Topics: Pharmaceutical, Liquid & Slurry

Written by Sentry Equipment

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With proven sampling expertise since 1924, Sentry products and services provide business operations the critical insights to optimize process control and product quality. We deliver true representative sampling and analysis techniques to customers around the globe, empowering them to accurately monitor and measure processes for improved production efficiency, output and safety. Standing behind our commitments, we are determined to tackle any application, anywhere.