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Water Dispersible Granules (WDG) & Dry Flowable (DF) Formulation Products : Properties; Pros & Cons; Proper Use (Measuring). What is a DF / WDG?.
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Water Dispersible Granules (WDG) & Dry Flowable (DF) Formulation Products:Properties;Pros & Cons;Proper Use (Measuring)
What is a DF / WDG? • Water-Dispersible Granule (WDG) and Dry Flowable (DF) formulations are made by compressing (“aggregating”) a Wettable Powder (WP) into “dust-free” particles.
Review: Dry Formulations • Dust (D) • Granule (G) • Pellet (P / PS) • Wettable Powder (WP) • Dry Flowable (DF) = Water-Dispersible Granule (WG / WDG) Applied Dry
DF / WDG Characteristics Like WPs (and all other commonly-used dry-formulation products): density depends on the properties of the active ingredient and the carriers (inert ingredients)!
DF / WDG -- Disadvantages • Like WPs • form a suspension (not a solution) in a spray tank…so… • require significant agitation • may be abrasive to pumps, tips, etc. • may clog strainers/screens • hard to mix (however, many products are low-rate…)
DF / WDG -- Advantages • Like WPs: • easy to transport and store • less likely to be phytotoxic or harm treated surfaces than some other sprayable formulations (ex. ECs) because they don’t contain any oils or solvents
DF / WDG -- Advantages • An added benefit over WPs • reduced handler exposure risk: • larger, less “dusty” particles • reduced handling: • easier to take out of packaging • no weighing (if premeasured container is used) • …BUT…
While DF / WDGs have advantages, there is a “catch”: • To avoid weighing, mixer-loaders MUST use a product-specific measuring device • dedicated to a specific “batch” of product (may change from year to year) • w/ premeasured lines based on weight (density)
Description:Units of Measurement • Dry dry ounce, pound… milligram, gram, kilogram… • Liquid fluid ounce, cup, pint, quart, gallon... milliliter, Liter…
Dry Ounce Measure of Weight 1/16 of a Pound
Fluid Ounce Measure of Volume (Space Occupied) 1 fluid ounce = 2 tablespoons = ~ 30 cc’s (= 29.6 cm3) = ~ 30 mL (= 29.6 mL) = 1/128 of a US Gallon = 1/16 of a US Pint
Dry Ounce • Note the placement of the 1 dry-ounce (weight measure) mark:
Problems: • End users do not always: • understand the properties of WDGs/DFs • know why using the right measuring container is critical • remember that fluid and dry ounces are NOT the same
Problems: • Dealers/suppliers do not always give end users: • the right measuring device for the product • measuring containers with accurate labels and marks • measuring instructions = an explanation re: why using the right “tube” is critical
Problems: • Manufacturers do not always: • give dealers/suppliers information about DF/WDG products, and how to measure them properly • Package products with enough measuring devices • Identify which device “goes with” what “batch” of product
Measuring WDG/DF Products • Measure WDG/DF products ONLY with the device made for and sold with product. • Discard dedicated WDG/DF measuring containers when product is used up!
Take-Home Messages • Fluid and dry ounces are NOT interchangeable equivalents. • Different substances vary in density • Be sure you know what you’re measuring—and use the right method and device!!
Acknowledgements • Pat Hipkins at Virginia Tech University was the primary author of this slide set.