Most coffee growers in Vietnam’s Central Highlands know the “Đặng Tám sprinkler,” a home-grown irrigation nozzle with features that rival imported models. Its inventor, Đặng Tám—a farmer who left school after only the fifth grade—has surprised even professionals with his ingenuity.
Diagnosing the Weakness of Imported Sprinklers
Tám proudly shows the highest “diploma” he owns: a primary-school certificate from 1971, carefully laminated and kept for nearly forty years. “Back then,” he recalls, “class Nhất was like today’s fifth grade. War and poverty meant I had to stop schooling and take up farm work.”
Originally from Duy Xuyên in Quảng Nam Province, his family was relocated to the Central Highlands in the early 1960s and finally settled in Ea Phê commune, Krông Păk District (Đắk Lắk), where he still lives.
When large state coffee farms began expanding after 1975, farmers relied on imported rotating sprinklers—mainly from the former Soviet Union and Czechoslovakia. These metal devices needed high-powered pumps and often jammed: sometimes the head stopped turning, leaving some areas drenched and others dry. Tám, who grew coffee himself, knew these flaws firsthand.
In 1994 he started tinkering with broken sprinklers—first his own, then neighbors’. “Every irrigation season people brought me hundreds of faulty nozzles,” he said. Over time he pinpointed why they failed and began imagining a better design.
From Farmer to Inventor
It took nearly eight years of trial and error—and a few hundred million đồng from his coffee earnings—to build the machines, molds and parts for a completely new sprinkler.
Key innovations set his design apart:
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Two balanced jets, covering both near and far ranges, whereas imported models had only one.
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Plastic construction in durable PE, resistant to impact and deformation.
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Adjustable spray settings to suit any pump size.
These changes boosted irrigation capacity by 15–20 % and saved about 10 liters of diesel per hectare each watering. A pump that once handled eight imported heads could now run twelve of Tám’s. Yet his sprinklers sold for roughly one-third the price—about 225,000 đồng for the two-jet model.
Recognition and Growth
His invention quickly earned national accolades:
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2003 – Commendation from the Ministry of Science and Technology at the Vietnam Tech-Expo.
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2004 – Industrial design patent from the National Office of Intellectual Property.
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2006 – First prize in the Vietnam Farmers’ Technical Innovation Contest.
Tám was also recognized as an “Outstanding Farmer-Entrepreneur” in Đắk Lắk for 2002–2007.
Today he produces around 3,000 sprinklers a year for coffee plantations, vegetable farms and flower gardens across the Central Highlands, the Southeast and even northern provinces. Despite offers of more than a billion đồng to buy his patent outright, he refuses to sell.
Travelers along National Highway 26 from Buôn Ma Thuột to Nha Trang can see a striking cement monument of his sprinkler—a symbol of both his product and his decade-long journey of invention. Now Tám is researching improvements for deep-well pumps to better serve the region’s coffee growers.
As local farmer Lương Nha notes: “Tám’s sprinkler works even with small electric or diesel pumps—lightweight, durable and spraying far.”
Nguyễn Kim Hùng adds: “Its plastic parts are easy to replace; if something breaks, you just swap that piece—very economical.”
Agricultural scientist Dr. Hoàng Đức Liên sums it up: “Like many Vietnamese farmers’ inventions, the Đặng Tám sprinkler arose directly from practical need and quickly proved its value in the field.”