Rotary batch blender mixes biological products that boost farm crops

SASKATOON, SK, CANADA — Agriculture has never been more challenging and fertility efficiency tools, such as inoculants, more important. Modern farmers rely on technology and production practices to significantly increase the yield of their food crops. Biological products like inoculants are a vital part of that strategy.

Novozymes Biologicals is an industry leader in developing and manufacturing inoculants, which are a uniform mixture of live soil fungi and bacteria that enhance a plant's ability to use soil nutrients, helping farmers attain abundant crops. The company's investments in research and development have led to the introduction of the first pre-sterilized self-sticking peat-based inoculant in the Canadian marketplace. The researchers' efforts have also pioneered the use of phosphate inoculants and introduced TagTeam®, the first multi-action inoculant. "Because the TagTeam inoculant combines two microorganisms, though," said Greg Holloway, manufacturing manager, "we needed a blending system that would ensure equal and thorough distribution of both organisms onto every particle of the carrier so we could then produce a granular formulation."

Finding such equipment was a challenge. "We set ourselves apart in the inoculant industry," continued Holloway, "by delivering the highest quality product, so we don't cut corners anywhere. In 2001, I tested a number of continuous and horizontal blenders, as well as a few rotary blenders, but none met our quality requirements until we encountered a Munson rotary batch blender at a nearby plant. In the tests we conducted, that blender gave the best results for our multi-action product."

When Holloway and his team returned to their company after the tests, they placed an order for a 300 cu ft (84 cu m) capacity 700-TCS300-MS rotary batch blender from Munson Machinery, Utica, NY.

Achieving uniform distribution of bulk solids and liquid additions

To ensure the Munson blender could meet Novozymes Biologicals' quality standards, Holloway tested the blender's coating and mixing capability by using the blender's spray nozzle to dispense a colored die onto white material. "We then put samples under a microscope to establish the percentage of coating coverage and found that the coverage was very good. The minute variations we did find were due to the hardness and size of the seeds, which made it more difficult to see the coatings rather than to insufficient coating.

"We also did separation tests for particle sizes," Holloway continued. "I think the mixing flight configuration inside the blender is the key to the homogenous results we receive." In addition, continuous rotation throughout the entire blending cycle assures that all materials remain in motion, preventing segregation.

Blending and coating of solids in stages

The raw material carrier arrives in mini bulk bags and is stored on the Saskatchewan site until blending time where the bags are then transferred and emptied into a hopper. From that hopper, the carrier material is conveyed to a weigh hopper positioned on one side of the blender. On the opposite side of the blender is another hopper that measures the needed amount of microorganisms.

The blender's rotating drum is supported by two large trunnion rings that ride on heavy-duty alloy roller assemblies. Standard configuration is for a stationary inlet at one end and a stationary outlet with a discharge gate at the opposite end of the blender. In this application the blender has access doors at each side to ease sampling and cleaning.

Portions of the batch constantly contact the sides of the drum cone, being gently folded back towards the horizontal axis, effecting a diagonal as well as a vertical tumbling motion. Then lifters inside the drum continuously cut out portions of the batch and fold them back into the main body of the batch. These mixing actions ensure 100 percent uniformity of each supplement.

The spray attachment, which is mounted near the top of the blender, sprays material that is constantly tumbling and cascading, resulting in uniform distribution of liquid additions. The mixed material does not come in contact with the spray nozzle, preventing clogging.

After blending, the internal flights and baffles elevate the batch toward the discharge gate of the stationary outlet, discharging virtually 100 percent of the batch into a two-tank staging hopper that feeds the bagging line for final bagging before distribution to farmers.

"Each batch is sampled to ensure the microorganisms remain alive and homogeneously coat the carrier," said Holloway. "We take samples going in, pull samples during the blending cycle, and take samples from the finished product to ensure the highest quality of product is available to our customers."

Blender increases batch production

Holloway also uses a small-scale blender, a Munson MX5 rotary mixer, for scale up work. "The small blender allows us to efficiently and quickly test a variety of production parameters." Both blenders contribute to Novozymes Biologicals' high production rate.

The 300 cu ft (84 cu m) capacity rotary batch blender homogeneously mixes and coats two microorganisms on a carrier.

The mixer discharges virtually 100 percent of the batch before the blended inoculant is fed to the bagging line.

TagTeam® multi-action inoculant helps plants make better use of soil nutrients. The synergy of two microorganisms results in higher crop yields than those produced by other inoculant products.

Novozymes Biologicals samples each batch to ensure the microorganisms homogeneously coat the carrier.