Best Practices for Mixing and Agitation of Small Rate ProductsVibrance® fungicide and the upcoming Vayantis® fungicide are examples of Syngenta Seedcare products with a low application rate. These products (once registered in the case of Vayantis) can be applied through Direct Inject systems where a dedicated line is used to pump and dose the product, or they can be mixed into a slurry in a mix tank (slurry tank) prior to being applied.

Adding these fungicides into treatment slurries is probably the most common scenario in seed treatment plants. Mixing products into a slurry can be very easy and effective when one follows the best practices outlined in this document, especially with low use rate products.

The goal of mixing slurries is to have the right amount of each component and achieve a homogeneous mixture of all components in the mix tank. Adding the right amount of product in the tank is not enough and it is essential that you agitate the products until a homogeneous mixture is obtained in the entire mix tank (top to bottom).

This technical sheet focuses on how to properly mix a slurry using Mechanical Agitation, Hydraulic Agitation (transfer/recirculation pumps) and Pneumatic Agitation (Pro-Blend®) Systems.

Mechanical agitation is accomplished with an impeller such as propeller, paddle or turbine that enhances mixing and dispersion of particles.

Propeller and hydrofoil style impellers are commonly used for suspension of solids that may settle at the bottom of a tank.

It is very important to correctly position the mixer off center on your mix tank in order to achieve proper agitation. Positioning it at a 15-degree right of the center line provides better product agitation. When positioned in the center it often creates a vortex, but heavy particles are usually not brought to suspension as they are forced to deposit at the bottom by the liquid movement in the tank.

Another style of mechanical agitation uses top-mounted motors (see Cimbria, USC, and KSi examples to the right). These are typically the common types of mechanical agitation used in seed treatment plants.

The most common type of impellers used with this style of mounts are axial and radial flow impellers. These impeller styles are desirable because they use higher shear mixing than propeller style impellers. The higher shear does a better job of keeping the solid particles in the mixture suspended, and with most modern seed treatment formulations being flowable suspension formulations, these high-shear impellers perform best.

Axial flow is typically best achieved with a pitched blade turbine. These types of impellers push product down to the bottom of the tank, which then flows to the top and back down.

A radial flow impeller pushes product towards the walls of the tank. Radial impellers are typically also used with some type of baffle to increase the ability of this impeller to create top-bottom mixing of the vessel that the impeller design doesn’t allow for without a baffle.

Source: Cimbria Heid

Source: KSi and USC

1. Mechanical Agitation

BUILDING A SLURRY:

There are different possible scenarios for mixing low application rate products like Vibrance, with other seed treatment formulations, each adopted to seed treatment plants set up and company preference.

SCENARIO 1: MIXING PRODUCTS IN A SLURRY TANK (MIX TANK)

When equipped with a slurry tank (mix tank), utilize a transfer pump system to start adding the desired components of your recipe in the mix tank. Small rate products may have to be added manually due to pump restrictions and amount to be added.

The Seedcare Institute recommends use of W-A-L-E-S method that outlines proper mixing order of slurry components. This can help reduce slurry incompatibilities as well as allowing better product miscibility of different formulations.

THE W-A-L-E-S METHOD OF PRODUCT MIXING

Add 2/3 of required water volume

Start Agitation

Add Wettable Powders or Wettable Granules (uncommon in Seed Treatment)

Agitate thoroughly until fully dispersed

Add Liquid Flowables and Liquid Suspensions

e.g. Cruiser® 5FS, Avicta® Complete Corn 250, Vibrance Cinco, Vibrance, colorant, polymer, etc.

Start with the higher rate products and finish with lower rate products (e.g. Vibrance)

Add Emulsifiable Concentrates

e.g. Apron XL® LS

Add clear Solutions and others

e.g. liquid Micronutrients, etc

Finally add last 1/3 of water.

Continue to mix until all products are fully dispersed. Remember that each recipe is different and should be optimized for mixing performance.

Make sure to adjust the application rate of the slurry to account for all the products added to the mix tank.

Also, when adding micronutrients and other classes of seed treatment products it is important to run a compatibility test (Jar Test) prior to mixing a large batch.

W

A

L

E

S

Extracts from FMP courses and Handbook of Industrial Mixing

Source: Bayer Seed Growth

Wall baffles, which are longitudinal metal or plastic strips attached to the inside walls of the mix tank enhance the flow of liquid in the tank and result in a mixture becoming homogenous more quickly than in a system without them.

SCENARIO 2: MIXING A PRODUCT INTO ANOTHER PRODUCT TOTE (PACKAGE)

When utilizing Avicta Complete Corn 250 for example, there is enough head space in a 265-gallon tote to add low application rate products, like Vibrance, in it. For use on corn, for every 265 gallon of Avicta Complete Corn 250, you need an equivalent of 3.38 gallons of Vibrance for example.

RECOMMENDATIONS:

f Utilize mechanical agitation (pitched blade axial turbines work well, or a folding variant of these that allow a larger turbine to be inserted through the 6" buttress treated top hole)

f Have agitation turned on while adding Vibrance into the larger tote (265-gallon tote)

f Pour Vibrance slowly into the tote while agitation is occurring; Ensure gentle initial mixing to avoid product splash

f Agitate the mixture thoroughly for 30-60 minutes at low rpm speed to allow the products to evenly mix in the tank. If applicable, change position of the propeller in the tank to be 15 degree off the center to optimize mixing in the corners when utilizing a propeller or hydrofoil style impeller

f Remember: Over-agitating does not always mean better agitation. For seed treatment products running propellers at high speeds for prolonged times can result in over sheared formulation causing it to break down

f It is a good practice to recirculate the slurry prior to application at the beginning of every treating day to guarantee all particles are in suspension. Usually 5-10 minutes is enough for most mixtures depending on pump size

f Make sure to adjust the new application rate to account for all the products in the tote combined

This is amongst the most common types of agitation/recirculation systems in seed treatment plants where a pump (centrifugal or peristaltic) is utilized to move liquid through a close loop creating liquid agitation/turbulence.

All major seed treatment manufacturers (e.g. Cimbria Heid, Gustafson, USC, KSi, etc) have re-circulation and transfer kits available with specific couplers to allow for easy transfer, agitation and recirculation.

2. Hydraulic Agitation (Recirculation/Transfer pumps)

Source: KSi Re-recirculation and transfer kit Source: Bayer Seed Growth

SOTERA SEED TREATMENT PUMP 400B SERIES

Electric Driven Mix Pump

The Mix Pumps are a simple way of agitating and extracting product from chemical manufacturers 15 gal. and 30 gal. containers. Pumps are shipped preassembled and ready to use out of the box. Powered by 120V.

Source: www.farmchem.com

3-TANK TURNOVER RULE

In order to properly agitate your product or slurry we use the 3-tank turnover rule in which the equivalent of 3 times the volume contained in your tank/tote needs to move through the pump. In order to calculate how long it would take to move that amount of liquid you can use the formula below:

AGITATION/RECIRCULATION STEP BY STEP

When utilizing hydraulic agitation is important to follow a couple of ground rules to achieve optimum mixing performance:

f Lines/hoses need to be cleaned/purged prior to utilizing the system to avoid product contamination and incompatibility issues

f Pump size selection is important for determining for how long your system needs to run to achieve proper slurry mixture

f It’s important to follow the W-A-L-E-S method for order of addition

f Add higher volume products first in your mix tank or tote followed by the lower volume products. This will help products to blend in thoroughly

f Use the 3-tank turnover rule to agitate/recirculate your product and your slurry

Tank Turnover Time (minutes)

=

Tank Volume (gallons)

Flow rate of fluid (gallons per minute)

RECIRCULATION OF YOUR SLURRY

Recirculation is a common technique recommended before applying seed treatment products. Once your mixture/slurry is prepared always remember to recirculate over time or before each day/shift use. This will guarantee that all solids will be in suspension and evenly distributed.

This transfer/recirculation kit can be found on www.FarmChem.com and is great for daily work on product extraction and recirculation prior to treating seeds. It is, however, not well suited for totes above 30 gallons due to a flow rate that is not high enough to provide excellent agitation in 110- and 265-gallon totes. For those totes, a larger, air-operated diaphragm pump is recommended.

Advantages

f Options with and without Recirculation

f Totalizer Meter displays total number of ounces or gallons used

f Tote Mixer powered by 120V

3. Pneumatic Agitation/Recirculation (Pro-Blend)

Pneumatic systems make use of pressurized air to move the liquid in a certain container like a tote or keg. Although it is not the most common technologies used for agitation it can be adapted for this purpose.

Syngenta Seedcare Institute has tested and validated the Pro-Blend technology from Micromatic™. It utilizes timed pulses of pressurized air that quickly and completely mix the contents of a container in a closed system dry-break design. This device maximizes slurry mixing efficiency while minimizing worker exposure.

HOW PRO-BLEND TECHNOLOGY WORKS

The Pro-Blend Closed Mixing System technology utilizes pulses of air to agitate mixtures.

1. Powerful pulses of air are ejected through the down tube and forced along the bottom of the container

2. Large flat bubbles form immediately and rise to the surface

3. Bubbles will continue to rise, bringing settled and/or heavier product to the surface

4. As each bubble breaks the surface, it pushes liquid across the top and down the sides to the bottom of the container, circulating the contents and providing a homogeneous mixture

ONE PULSE PER SECOND RULE:

It is recommended to adjust your Pro-Blend device to a 1 pulse per second frequency to form large size bubbles and hence maximize agitation. Increasing the frequency of pulses will create smaller bubbles that won’t move the liquid efficiently and could also cause air to be incorporated into the product/formulation. Operating pressure of the Pro-Blend is also not to exceed 40 psi on smaller totes, or as stated on the side of the Pro-Blend equipment.

PRO-BLEND CLOSED MIXING SYSTEM

OPERATION TIME:

The operation time for optimum agitation depends on the product container size and combination of products being mixed. Excellent mixing is usually achieved after 20-40 minutes of blending for large totes. See reference values below:

f 15-gallon keg (10-15 minutes)

f 110-gallon tote (15-20 minutes)

f 265-gallon tote (25-40 minutes)

OTHER REQUIREMENTS FOR USE OF PRO-BLEND:

f Micromatic fittings & Dip-tube (down tube)

f All Syngenta 15 gallon kegs come with down tube and Micromatic fittings

f For larger totes use down tube with mix plate

f Source of pressured air should not exceed 125 psi

Branded Case Pro-Blend Mixer

Dispense Coupler

Plastic Container Valve

Stainless Steel Container Valve

Down Tube with Mix Plate / Foot

Syngenta customers have a special discounted rate when purchasing Pro-Blend in North America. For more information and User Manual please access the following link:https://www.micromatic.com/syngenta

4. Final Considerations

All photos are the property of Syngenta or are used with permission.

Syngenta hereby disclaims any liability for Third Party websites referenced herein.

©2020 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your local extension service to ensure registration status. Vayantis is not currently registered for sale or use in the U.S. and is not being offered for sale. Avicta Complete Corn 250 is a Restricted Use Pesticide. The trademarks or service marks displayed or otherwise used herein are the property of a Syngenta Group Company or their respective owners.

GS 6184_2_1 SLC 12803A 08-2020

When preparing any mixture or blend of seed treatment products consider performing a stability/compatibility test (Jar test). This will help prevent incompatibility issues happening on large scale and issues that may arise during application such as:

f Product viscosity changes

f Inability to recirculate/agitate products

f Hoses and filter clogging

f Atomizer/spinning disk clogging

f Poor seed coverage

f Excessive product build-up throughout the system

f Active ingredient degradation