Friday, October 11, 2013

When and Why Do I Need Cooling for Three Roll Mill Rollers?

A client who intends to use three roll mill for algae exfoliation visited our lab the other day, trying to process several kilos of algae harvested from the Norwegian sea. We seldom use our demo lab model to do large samples like that. However, they explained that only a small amount of oil can be extracted and they need a significant amount to test the results. For such a novel application, we gladly agreed.

As the milling went along, the rollers, which are made from stainless steel, got warm and raised the concerns of our client. They want the rollers to stay below 40°C to prevent the algae material being oxidized. And we had to turn on the cooling system, which can maintain the roller temperature ±2-3°C around ambient temperature.

It is very common for rollers to get warm after a prolonged period of continuous running. The roller surface temperature increases as a result of heavy friction between the rollers brought by the high shearing force necessary for successful grinding. When the surface temperature exceeds 70°C, damage to the gear system might occur. Under such circumstances, active water cooling is recommended. If, in this customer’s case, a certain temperature is required to prevent deterioration of the material, water cooling is of utmost importance as well.

The mechanism behind water cooling is not a complicated one. As you can see in the illustration above, water is first pumped into the built-in water tank on the machine, usually with a submersible type pump (so that it can be placed in a larger water container for recycling). This cooling water goes in through the pink tunnel and flows into the blind hole inside the roller. The blind hole is designed with a slight slope so that water eventually flows back into the water tank. There is a water outlet through which warm water gets out of the tank. The water recycles in and out of the larger water container, such as a bucket, and does it job keeping the desired temperature. Be sure to adjust the water flow by controlling the pump to keep the liquid level constant in the water tank. The same system can be used to heat up the rollers if hot liquid is pumped into the rollers. 

Last but not least, although we call it water tank, water is not the most desired liquid for the job. We recommend the use of at least 50/50 coolant and water. Coolant with anti-corrosion additives, such as this one, includes a corrosion inhibitor that balances the negative acidic effects that can develop over time in antifreeze and water solutions. It also stabilizes the pH level which helps reduce rust and prevents electrolysis, mineral deposits and pre-existing scale build-up from forming resulting in potential core damage for long term protection.

Wednesday, September 25, 2013

Maximize Ointment Mill Throughput

Topical formulations greatly reduce the risk of side effects caused by oral medications, offering the potential to deliver at the site of inflammation while minimizing systemic concentrations. As a result, the demand for pain creams has increased significantly. One pharmacy asked us to help optimize the output of a lab model ointment mill they bought from us, hoping to make 80kg of creams daily. 

What we thought would be a simple task of adjusting the speed or the gap sizes turned out to be a full-scale lab experiment. The ointment pre-mix was so thick that it required an unusual combination of front and back gap settings to make it work. Even so, the hourly output was still significantly lower than other types of creams due to the material property. Here, we want to introduce the scientific method our engineer utilized to maximize throughput, so that customers can make the most out of this award winning lab model ointment mill

Our engineer first observed the behavior of cream on the roller. The initial setting was 50 microns for both gaps. The cream was slow running into the feeding area and was stuck on the middle roller which meant bad transfer to the fast roller and the hence collection blade. The conclusion was that the gap between the slow and middle roller should be wider, while the gap between the middle and fast roller should be narrower. After a few rough adjustments, our engineer decided to fine-tune the gap settings with a series of experiments.   

He started from 150-micron back gap (gap between slow roller and middle roller), and 20 micron front gap (gap between middle roller and fast roller). First he needed to confirm for this particular kind ointment, higher speed lead to higher output. As it turned out in experiment 1to 3, higher speed did lead to higher speed, and the maximum speed didn’t cause the material to splash. He would use maximum speed for all the rest of the experiments.

Next step, he adjusted the front gap to 30 microns. The transfer from the middle roller to the fast roller got worse and the throughput was down. In experiment 5, he kept the front gap at 20 microns and used a narrower gap (100 microns) between the slow roller and middle roller. The throughput was down again, which meant the back gap needed to be wider. After a total of eight experiments, he settled at 250-micron back gap and 20-micron front gap. Our customer was able to reach their desired output as a result. 

To review experiment data, please go to

Anyone using an ointment mill, or a three roll mill as other industries call it, with the goal of maximizing its output, can give this optimization process a try. Contact us if you have questions on how to do it successfully. 

Wednesday, August 21, 2013

Our Lab Model Three Roll Mill Named as Finalist in the 5th Annual 2013 Golden Bridge Awards for New Products and Services!

Our Torrey Hills T65 (2.5x5) three roll mill was named as a finalist for the 2013 Golden Bridge Awards under the category of New Product and Service. Golden Bridge Awards are an annual industry and peers recognition program honoring Best Companies of all types and sizes in North America, Europe, Middle-East, Africa, Asia-Pacific, and Latin-America, Best Products, Innovations, Management and Teams, Women in Business and the Professions, and PR and Marketing Campaigns from all over the world.

We started from the vision of a compact, robust, and continuously feeding mixing device that blends viscous materials. The patent pending overall design is visually appealing. Under the hood the revolutionary mechanical driving system delivers high shear force with minimum operating noise. We crafted the rollers with 5μm concentricity and 0.5μm surface finish for precise applications. The rollers are cored for either cooling or heating to keep the temperature at the desired level. We carefully matched the electrical components and bearing systems to maximum the power, dispersing efficiency, and throughput. A VFD is used to provide variable speed control. As a result of these innovations, minimal particle size milling down to submicron level occurs. An easily accessible pull switch adds extra operator protection. This mill is positioned as a leader in mixing tool for a wide range of industries including paints, inks, thick film pastes, adhesives, coatings, ceramics, cosmetics, food, and pharmacy compounding, with comparative advantages in mixing efficiency, continuous feeding capability, and quality control.

Tuesday, August 13, 2013

Ointment Mill - A New Focus of Interest

An engineering colleague and I went to visit a pharmacy compounding customer last week. Three roll mill used in pharmacy compounding has become a hot sale since the beginning of this year. Exakt 50 used to be the standard equipment to make medicated ointment. However, more and more pharmacies are expressing their concerns about its productivity limit and turning to us for ointment mill solutions. We are excited and ready to give our best to this market. 

This particular compounding pharmacy in California is doing extremely well and seeing more ointment orders by the month. Their focus is on pain and hormone ointments. Surrounded by friendly pharmacists and technicians, we offered a two-hour long product training session, letting them learn the best gap size for their particular kinds of ointments in order to maximize output. This 2.5x5 three roll mill lab model, which potentially doubles the output of that of Exakt 50, turns out to be the perfect tool for them to fulfill their monthly orders.

Apart from the 2.5x5 model, our 6x12 model has also generated plenty of interest from pharmacy compounding market. From pain ointments to anti-aging creams, our customers found it to be a great pilot production tool for the expansion of their businesses. 

Tuesday, July 30, 2013

Welcome to Happy Three Roll Milling Blog!

After five years working with people in different industries using three roll mill to make refined products or conduct scientific research, I'm still thrilled by this traditional yet irreplaceable machine tool. Paints, inks, thick film pastes, adhesives, coatings, ceramics, cosmetics, food, and pharmacy ointments ... you name it! It never fails to do a perfect job mixing, refining or homogenizing viscous materials.