Putting a spin on irrigation filtration
By Lalkesh B Singh, E.I. DuPont India Pvt. Ltd.
The hydrocyclone, an established irrigation filtration technology, has been successfully redeveloped by India's leading irrigation company to take advantage of DuPont™ Zytel® Nylon Resins to replace primary metal components, including the main body. The new design offers multiple benefits thanks to its adoption of engineering plastics, including greater service life, enhanced robustness and lighter overall weight.
Automat Irrigation Pvt. Ltd., a part of Automat Industries Pvt. Ltd., which was formed in 1972, has adopted a philosophy to offer quality, top-of-the-line irrigation products for customers both in India and across the globe, where it exports to more than 85 countries. The company designs and manufactures a wide range of irrigation products, including sprinklers, foggers, leak-prevention devices, air-relief valves, screen and disc filters, hydrocyclone filters, PVC ball valves, head units, venturies, and a wide range of accessories.
Automat Irrigation has been a DuPont customer for a number of years, using a variety of polymers for its products as it steadily migrated over from all-metal construction. However, it was the redesign of the hydrocyclone filter that has most capably demonstrated the value of looking at alternative materials for components and parts traditionally manufactured from metals.
According to Vijay Warke, Vice President—Operations at Automat Irrigation: "We are the largest manufacturer of metal (brass) sprinklers in India. For the last five years we have been converting many of our products and components to plastic, including the manufacturing of sprinkler components from DuPont™ Delrin®, thanks to its stiffness, creep and impact resistance and its ability to cater for the design requirements necessary for reliable drip tubing connections. The redesign of the hydrocyclone was a natural progression of this work and typically—for components where strength is a major requirement—we discussed our needs with DuPont."
Hydrocyclone filters use centrifugal force to separate particulates from liquids—in this instance from irrigation water—in order to protect pumps, valves and other irrigation systems from damage and abrasion caused by suspended solids. In operation, water enters tangentially at the top of the inverted-cone-shaped vessel and immediately starts to spin around the inside circumference. As it heads toward the bottom, enough centrifugal force is generated to move heavier particulates outward where they spiral down and can be removed via the outlet at the bottom of the vessel. The remaining particulate-free water then migrates to the center axis of the vessel and moves up toward the outlet at the top, where it is extracted and passed onto subsequent equipment used in drip/micro irrigation.
"We designed the new hydrocyclone ourselves," Warke continues, "but once the mold had been made and we tried the design, we quickly realized that we were not getting the required performance in terms of strength. It was at this stage that we contacted DuPont, who, following a number of visits over a six-month period, was able to suggest modifications for both the material grade and their subsequent processing. We took the suggested grades on trial and one of them turned out to be very successful. DuPont also helped us undertake life testing, which was important for the worldwide warranties we intended to offer."
The ultimate aim of the redesign exercise was to improve the life of the cyclone units and reduce their overall life costs. The main issue faced by the units fabricated from metal is corrosion, which can eventually cause complete failure. Plastics could certainly address the corrosion issue, but there was always a concern regarding their strength, especially when you consider some of the forces and pressures involved. As it turns out, the DuPont™ Zytel® nylon resin used in the new hydrocyclone design offered the required performance level, such as dimensional stability, outstanding combination of stiffness and toughness, tolerance for moist and hard-water environment, coupled to very good flow characteristics, which make it suitable for filling the 2.5 kg part and providing it with a good surface finish.
The use of plastics has also reduced the overall weight of the unit, leading to reduced operator installation effort and reduced transportation costs for export sales. All in all, this is a fantastic example of where plastic has surpassed metal in many different criteria and has produced multiple additional benefits for both the OEM and the end customer.
Automat Irrigation Pvt. Ltd.
Plot No. 4-5, Sector-3A, IIE
Sidcul, Bhel, Haridwar (U.K.),