The Monitor

Production Process Insights

Safe Chemical Container Sampling with Low-Emission Thief Sampler

Posted by John Schadt on 8/10/16 1:23 PM

Chemical containers waiting for sampling

Chemical companies often need to use hydrogen peroxide and solvent for synthesis and purification processes. To verify quality and integrity of these chemicals, they need to sample and analyze them. These samples can be obtained directly from intermediate bulk container (IBC) loading or unloading stations. IBC are stackable, reusable industrial containers that can safely and efficiently store and transport liquids and solid granules, including chemicals, food ingredients, solvents or pharmaceuticals.

Because many chemical substances and their fumes can be toxic, minimizing operator exposure during sampling is important making a portable manual low-emission (low-e) sampler the preferred method. Low-e samplers are safe, simple to use, and yield representative samples for accurate analysis, keeping liquids and gases contained.

A need for minimal exposure, small sample volume and durability

One chemical customer needed a sampler for its peroxide and solvent. However, in this application, the sample point pressure was only 1.5 psi to 10.9 psi – too low for a standard portable manual low-e sampler – with no sample return point available.

Requiring a minimal two ounce sample size created another restraint for this application.  Finding a manual pump to transfer the sample to the portable sampler also proved difficult, as the volume dispensed by most commercially available pumps was much greater than the required sample volume.

With no sample return point available, there was no practical way to purge the sample from the transfer lines. Construction materials for these pumps, specifically the seals were also not compatible with the customer’s process, which included peroxide requiring more durability.

Specialized low-emission thief sampler solution

The customer application allowed for extracting samples directly from the IBC at the unloading station through an access point in the top. As the IBC are stored in a warehouse, sample analysis needs to verify contents before placing the container into service.

To best meet customer needs, the lower body of the Sentry® MVS manual low-e sampler was adapted to create what is known as a thief sampler. This Sentry MVS thief sampler solution was more sophisticated than typical thief samplers. A stainless dip tube was attached to the sample inlet port, and a cylinder added to the vent port. The cylinder was sized to prevent over-filling of the sample bottle. This innovative body design still allowed usage of the standard low-e needle sets and bottle shrouds or adapters.

After the bottle is filled the liquid remaining in the dip tube is purged back into the IBC by pushing the cylinder plunger back in. The safety of the operators and the environment is of utmost importance in chemical applications – and this special low-e sampler adaptation ensures that, while illustrating how our engineers are ready to consider any application, anywhere.

Learn more about our chemical & petrochemical sampling solutions.

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Topics: Hydrocarbon Processing

Written by John Schadt

As a Sr. Product Specialist, John Schadt draws on his more than 30 years of Sentry experience as a Drafting Supervisor, Engineering Applications Assistant and Product Specialist. Schadt has been involved in several Sentry patents and has been instrumental in product design, improvements and applying Sentry’s products to meet various customer application needs. He continues to apply his tremendous dedication, great ideas and in-depth knowledge of Sentry products to every project and customer.

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