Thompson is passionate about helping others. We help others by making dryer systems work like they are supposed to. A well-designed and well-built Thompson dryer system gives our customers and their communities the best opportunity to be profitable and successful. We believe in the American Dream, that hard work and ingenuity lead to success. We know it because we have seen it in the success of our customers, our team members, and the companies we work with.


We make the world and our customers cleaner, safer, and more prosperous.

We exist to help you and your plant. Your plant is only successful if your equipment is running like it should. Our rotary dryers can be a key piece of that, we design them to last for years with as few shut downs as possible. One of our dryers ran for at least 16 years without a trunnion or bearing failure, another drum has been rolling for over 40 years, without a weld on it since installation. Our systems run cleaner and longer than our competition’s. That means a better return on your investment, less downtime, and even cleaner air around your plant.


Thompson uses our generations of experience to design and service industrial equipment that gives our customers the best opportunity to be profitable and successful.

When Walter “Ted” Thompson started to tinker with his equipment in the 1940s, he did so with the intention of finding a way to improve efficiencies and profitability. He knew that his path to success lay in his equipment. If it did not operate as it was supposed to, his ability to thrive would be hampered. Early on, other plants saw the achievements Thompson had and would ask for assistance with their equipment. That demand helped shift Thompson from plant operator to full time system designer and maintenance. Now into the fourth generation of Thompson, that desire to continuously enhance and improve has led to over 65 years of experience with dozens of patents pertaining to all aspects of industrial dryer equipment.

As a business, we know that the goal of your business is the same as ours: to make money by increasing net profits while simultaneously increasing cash flow and the return on investment. If your equipment is not as efficient as it can be or does not last as long as it should, you cannot be as successful or profitable as you could be. We want our customers to experience the highest level of success possible, therefore, every piece of equipment produced or service rendered by Thompson has one goal in mind: to give you, our customer, the best opportunity to succeed.


“We want to raise the bar for the standards our customers expect when purchasing industrial equipment.”

We are not satisfied with just doing a good job, we want to do a great job that will “raise the standards our customers expect when purchasing industrial equipment.”

We firmly believe that our systems give the company and its owners the best opportunity of being profitable and successful. We believe our equipment matters to the men and women that use it, the plant’s business partners, and their communities. Because of this we challenge ourselves to do a better job each time and the best way to do that is raise the expectations of the market place. We want to make sure our equipment works the way we told you it will; the way you expect it to.


  • Deliver Excellence: We believe our customers deserve excellence from our equipment, service and overall experience.
  • Continuous Improvement: We constantly evaluate our processes to improve them and we encourage our team members to grow professionally and personally so we can serve you better.
  • We Do Work That Matters: We know the work we do matters to the men and women that use it, our customers’ business partners, and their communities.
  • The Golden Rule: As you wish that others would do to you, do so to them.
  • Integrity: We believe that our word should be good and that our actions must be consistent with our words.
  • Responsibility: We believe in personal accountability and asking “What can I do to help?”
  • Teach Why: Our team member are experts; they understand not just how and what, but the why behind our decisions and designs.
  • Have Fun: Passionate team members, remarkable products, amazing service, and an enjoyable work environment create a fun atmosphere which leads to success.


Like most companies, Thompson has the universal goal of making money, but this is not enough to ensure we deliver on our Mission. To do this, we apply the following conditions: (1) provide a secure and satisfying environment for team members and (2) provide satisfaction to the market. Not only do we care about meeting our goal and conditions now, but we are also concerned about meeting them in the future. This ensures we are serving our customers and team members.

Fulfilling these two conditions has given us our generations of experience and our customers the best opportunity to be profitable and successful. By providing a secure and satisfying environment we have great team members who believe in our Mission, our Vision, and our Values. Our amazing team provides satisfaction to the market by meeting our customers’ needs and delivering solutions.
Our Heritage

Thompson began in 1945 as an alfalfa dehydrating plant. After our first operating season we found the process equipment available to us lacking, so we began to design and build our own harvesting, processing and drying equipment.

Soon other companies in the industry were seeing our success and began approaching us to build their equipment. In 1947 Thompson sold our first drying system. Over the next 36 years, we performed all aspects of production at our three alfalfa plants from planting to pelletizing, even marketing and sales. At the same time we continued to build equipment both for our own plants and for sale. This combination gave us a comprehensive knowledge of operating a production facility and a unique opportunity to experiment with our dryers, innovate our methods, and modernize our equipment. In the early 1980s we stopped our alfalfa production choosing to focus on developing new dryer technology resulting in dozens of patents issued worldwide. Some of our innovations include:

  • First company to successfully install exhaust gas recycle (EGR) on a dryer system
  • Developed low inlet temperature drying to lower emissions and protect product quality
  • Integrated Thermal Oxidizer (ITO) as part of the drying system
  • Design of drum structure that allows for long life without excessive repairs
  • Developed technology to improve cyclone efficiency
  • USDA Approved heat-based Phytosanitation process
  • Developed continuous torrefaction process

Today this tradition continues as we research and develop new drying technologies. Our commitment to excellence and innovation has solidified our reputation as the unsurpassed industry leader in quality and reliability.

Design Philosophy

“Equipment should work like it is supposed to.”

Our Founder, Walter “Ted” Thompson, said those words nearly 70 years ago and we still live by those words today. In our view equipment must not only meet or exceed the expectations of capacity and end product quality; it must also be durable, efficient, and safe. Thompson designs industrial grade equipment. To us this means our equipment must have an expected useful life with little or no repair of at least 10 years at 8400-hours-per-year operation.

Thompson believes in caring for the environment and being good stewards of our natural resources. We design our dryers to dry “gently” which will naturally reduce emissions.


At Thompson, we take pride in being among the safest drying systems in the world. We have diligently researched many fires in drying systems from many different industries and incorporated what we have learned in our designs to prevent these kinds of problems from taking place. We design most of our systems without refractory to minimize residual heat in the system in the case of an upset condition. We have also developed modulating EGR, which uses low oxygen, high water-vapor content drying – which makes fires very unlikely.

Thompson uses modulating EGR during upset conditions to help reduce the possibility of a fire by keeping the oxygen content low in the drying gases. If possible, we use steam to pressurize the system to keep the atmospheric air out. This process has been patented by Thompson and is a major consideration for safe dryer system operation in any upset condition.

Should a problem occur and a fire does occur in a Thompson system, we provide ways to shut down the system safely. We use modulating EGR to minimize oxygen content low, as well as “Steam Purge” and regulated air venting to clear the system of combustible material.

In addition to incorporating innovative safety features into our designs, Thompson can also work with you to make your current drying system safer. For example, we have taken other manufacturers’ dryer systems which were prone to fires and/or explosions and modified them to where they run for years – with many different upset conditions – without incident.


As a result of early experimentation, Thompson learned about air quality control and emissions. Historically, drying systems in the alfalfa industry emitted anywhere from 5-20% of the dry weight mass they were processing. Thompson pioneered low emission drying systems, circa 1969, with a system that passed the stringent Bay Area Air Pollution Control District Process Weight Standard without any secondary cleanup equipment. We learned how to transfer the thermal energy to the material being dried without causing thermal damage. Thompson has never failed an initial air pollution test, and we have never failed an air pollution test when our equipment was in good condition and operated properly. Thompson Dryer Systems have passed the required EPA tests for ethanol plants including the EPA Method 25A test on an approximate 10-MGPY ethanol plant without a thermal oxidizer. This is made possible by using our innovative Exhaust Gas Recycling and Rotary Material Handling techniques.

Shortly after employing EGR on our own dryers, Thompson discovered that the proper introduction of EGR around the burner flame reduces NOx emissions on high NOx generation burners used in drying systems. The reduction was substantial; drying systems with NOx emissions of over 90 parts per million saw decreases down to 8 parts per million.

Knowing that volatile organic compounds (VOCs) would eventually become a problem, Thompson pioneered Low Temperature Drying for rotary drying systems. With EGR, the water vapor content increased significantly which also increased the specific heat of the drying gases. This allows the thermal energy to be transferred to the product at a lower temperature. This allows for a superior quality product. With the increased efficiency and the high specific heat drying gases, we were able to dry product approximately 100-400 deg F lower temperatures; which decreased VOC generation.

We also developed center fill flighting that allowed the drying gases velocity to be increased through the dryer drum. The increased volume of gases going through the drum at the same evaporation rate allowed more EGR which lowers the inlet temperature. Ultimately, we were able to decrease the inlet temperatures as ranging 900-1200 deg F. This combination of technologies has allowed our drying systems to function well within EPA standards, and in some cases, running without a thermal oxidizer.

The proper use of modulating EGR is a powerful tool to use in a drying process. Thompson has developed an Integrated Thermal Oxidizer (ITO) for our drying systems. The ITO uses a split modulating EGR flow to the dryer systems’ vertical combustion chamber. The top part of the modulating EGR split flow directs the vent gases (which would normally go to atmosphere) to the burner system. At that point, the vent gases are raised to the required oxidation temperatures and retained for specific time periods.


Efficiency is very important to dryer performance. Thompson has learned that an efficient drying system is safer and environmentally friendly. The efficiency of a drying system is completely dependent on its proper use of thermal energy and material handling.

1976, Thompson wrote a whitepaper titled “Proper Thermal Energy Application” that describes the drying process. The paper shows that Exhaust Gas Recycle (EGR), also known as Flue Gas Recycle, along with Rotary Material Handling (RMH) are paramount to proper drying. Over the years, proper applications of EGR and RMH have changed rotary dryer systems for the better. Today, most rotary drying systems use some form of EGR.

A rotary drying system requires a specific ratio of mass-of-gas to mass-of-material for stable pneumatic conveying. Historically this was always done with excess air flow. The drying and combustion gasses typically represent about one-third of the gasses going through the dryer. The excess air for stable pneumatic conveying is roughly two-thirds of the gasses going through the dryer. The excess air must be heated from ambient temperatures to the drying system exit temperatures before being rejected. This process requires 20-40% more energy for drying than a system with EGR. EGR incorporates some of the outlet gasses and recycles them back through the inlet of the dryer to make up stable pneumatic conveying. The EGR gasses are recycled at the same temperature and composition as the exit gases. When the drying system is at steady-state the gasses are primarily water vapor and products of combustion.

Another area where Thompson has made dryers more efficient is that EGR allows the product to be dried at a lower temperature. This decreases the thermal damage done to the product. When a particle incurs thermal damage, some of the mass of the particle is driven off as volatile organic compounds (VOCs) – commonly seen as smoke. Thompson discovered that avoiding this thermal damage by using EGR can produce as much as 9% more product mass than a dryer without EGR.

RMH involves the internal flighting system which is made up of both shell and center drum flighting. Thompson designs special flighting packages for different materials. We have flighting packages like the “tyne” flighting for the Oriented Strand Board (OSB) industry that can handle wood strips 0.035″ thick x 3″ wide x 24″ long at the rate of 50-60 tons per hour. We also have “T-Flighting” designs for smaller particles and tray type designs for high-velocity drying. Subsequently, we have more than 6 different major types of flighting packages used in various configurations; allowing our dryer systems to handle a wide variety of materials and sizes.


Thompson’s process control philosophy is centered on the axiom that “slow and steady wins the race.” Process changes are deliberately limited in how quickly they occur. The various control loops in the system are influenced by each other and by doing this, Thompson ensures that the system as a whole has adequate time to adjust as the change is made. Rapid changes in one part of the process would require other parts to change rapidly, which can affect product quality, efficiency, as well as the stability of the system. Slow changes eliminate these issues while providing a reliable and safe system.


Thompson has a firm commitment to research and development. In 1955 we began working on the first heavy industrial dryer drum design. In 1965 we set up two alfalfa dehydrating plants, each with two identical drying systems. We would always keep one dryer as a control standard while we experimented on the other. If our experiments were successful, these improvements would be applied to all of our drying systems. After that, the next round of experimentation would begin. Our research and development has led to our heavy industrial design dryer system and many other innovations resulting in over 50 patents issued worldwide. Some of the technologies pioneered by Thompson

  • Exhaust Gas Recycle
  • Rotary Material Handling
  • Steam Purge
  • “BallBuster” Flighting
  • Ingetrated Thermal Oxidizer
  • Radial Arm Tension Supports (RATS)
  • Biomass Fueled Burners