The Monitor

Production Process Insights

Find the best samplers for solids and powders

Posted by Rich Gaffney on 6/7/16 10:14 AM
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Sentry automatic sampler

A number of industries routinely conduct solid and powder sampling, ranging from cement and food and beverage, to pharmaceutical, petrochemical, mining, oil and gas, and power generation. This list illustrates the wide variety of solid and powder sampling applications, and it also proves that there isn’t a one-size-fits-all sampling solution.

Common sampling challenges with solids and powders

It’s frequently said that handling dry materials is more of an art than a science. Bulk solids sampling is susceptible to conditions upstream and downstream of the area where the representative sample is drawn, chiefly due to material flow properties. Even a few degrees of moisture fluctuation, for example, can skew results.

Aeration is another hazard to flow properties. Some materials aerate well, so placing a sampler along a free-flowing stream presents no particular difficulties. However, those same materials may solidify as they settle. A sample taken after settling will return drastically different results than that drawn in the process stream.

Another challenge that is often not considered is space limitations on the process line. Samplers vary in size and footprint based on application, so installation can be tricky if sampling goals and the equipment needed to accomplish them are not carefully examined and aligned.

Frequently asked sampler questions

Our engineers and technicians regularly field a variety of questions as companies consider automated representative sampling options. Generally, inquiries revolve around how samplers will react with products, if the sample will change in size and shape, and if weights and measures of products placed in containers will be affected since the sampler is removing material.

Likewise, sampler installation is often discussed, particularly as it relates to marrying equipment into current processes and how a sampler will perform its specific functions.

The concern is understandable, since failed sampling could lead to scrapped product and unanticipated downtime – in short, a lot of wasted money and time.

Sampling solutions for bulk solids

Given the number of external factors that could impact sampling, and the variety of specific applications, there is no one standard sampler solution. However, there is one proven approach to finding the sampler that fits your needs: working with a strategic sampling partner with expertise and experience applying best practices to solid and powder sampling.

For example, instead of leading with sampler recommendations, our application engineers focus first on working with your team to gain a thorough understanding of sampling specifics like your goals, the application, your process, line conditions, space availability and intended outcomes. Once we have a clear big picture, we can confidently advise you on the equipment you need for best results.

Generally speaking, our customers’ decision-making processes lead them to one of the most popular models of Sentry® automatic samplers for solid and powder applications:

  • Sentry PR automatic point sampler: Designed to eliminate product degradation, the Sentry PR sampler takes a point sample of free-flowing material from positive or negative pressure systems. The sample is taken when a solenoid-controlled air cylinder operates a reciprocating probe into the product flow. Suitable applications include pellets, powders, flakes and granules.


  • Sentry RX automatic strip sampler: The Sentry RX sampler takes a strip sample of free-flowing materials from positive or negative, horizontal or vertical dilute phase pneumatic conveying systems, bins, gravity chutes or hoppers. The sample is taken when a solenoid-controlled air cylinder extends a sampling tube into the process line. While in line, the tube continually takes sample and simultaneously discharges it to the collection point. Suitable applications include pellets, powders, granules, grain, seed and friable materials with an angle of repose under 50 degrees.


  • Sentry B1 automatic point sampler: The Sentry B1 sampler is a low-profile sampler for free-flowing and non-free-flowing materials from gravity chutes and hoppers. It is conformant to 3-A sanitary standards for use with sanitary product sampling. The sample is taken when a gear-motor driven auger draws the product to the discharge point. Suitable applications include powders, flakes, granules, powdered milk and pharmaceutical products, or sticky/clumpy applications with an angle of repose greater than 50 degrees.

  • Sentry ISOLOK® automatic point samplers: Three versatile models for solid and powder applications include the Sentry ISOLOK SAK, SAH and SAE samplers. Each offers sanitary, fixed volume sampling per cycle in batch or composite samples. Process or flow ports are always closed, preventing leaks or product loss, and there are no tubes or passages to become clogged. With Sentry ISOLOK models, seal design isolates the operator from the process at all times, with the sample captured in the container “locked out” from external influences. The samplers can be used for composite, batch or analysis sampling of powders, pellets and grain.


These are some of our most popular and versatile models, but they represent only a few options. Several other sampler designs are available to address applications that fall outside of the typical categories.

The Sentry brand has gained the trust of our customers because of our applications-based approach to truly learning their sampling needs and exceeding their expectations in aligning equipment with need. Learn more about our solid and powder sampling solutions.

Sentry's Industrial Representative Sampling eBook

Topics: Power, Cement, Food & Beverage, Downstream, Mining, Upstream & Midstream, Solids & Powder, Pharmaceutical, Any Application, Steam & Water

Written by Rich Gaffney

With 20-plus years of experience in the sampling industry, Rich Gaffney has worked with many client companies to help them solve their sampling, monitoring and measurement needs. Currently, Gaffney holds the position of North American Sales Director and leads a team of eight sales engineers. His career has been focused on sales and application engineering, and he passionately believes that taking the time to fully understand customers’ goals is the key to successful relationships. He believes in making every customer a commitment, and communication drives his success.