DriWater, Inc., a marketer of a jelled form of water that makes it possible to water tree seedlings and plants on a time-release basis, recently found itself in a classic good news/bad news position. The good news was that sales of its unusual product were rising. The bad news was that its gabletop carton-filling machine was woefully inaccurate.
One of every 10 cartons was rejected because it was over- or underweight. In either instance, the carton and product were discarded. Besides those expenses, the time and labor to fill new cartons added to the company's manufacturing costs.
"Our product is viscous, and full of air," explains Harold Jensen, DriWater's general manager. "And our carton forming, filling and sealing machine was equipped with a gravity filler. During filling, air bubbles would expand and contract within the product, leading to filling inaccuracies. And while it's not a terribly expensive product, too much waste or giveaway became expensive. On the other hand, if the carton's too light, well, let's just say the government takes a dim view of that."
Governmental agencies and a variety of large commercial/industrial customers use the DriWater product to foster the growth of seedling trees and shrubs in areas where water is scarce. These include deforested areas, mine reclamation, highway landscaping, desert restoration, erosion control, and vineyards.
To remedy inaccurate filling, DriWater installed a Neotron Model 1000 semi-automatic auger filler from GEI Mateer Burt (Wayne, PA). It replaced the filling portion of an older carton filling machine. As a result, it still produces 45 cartons/min, but much more accurately.
"I'd say it reduces our manufacturing costs by $300 per day," Jensen estimates. Conservatively speaking, he indicates that savings amounts to more than $54ꯠ a year. That includes material, product and labor. Payback on the machine was less than 11/2 years.
"People with the original carton filling machine recommended we change the filler portion," Jensen notes. "They make filling equipment for the milk cartons we use for our product, while Mateer Burt doesn't have the equipment for forming and sealing cartons. So we mounted the Mateer Burt filler to the machine, adjusting timing and components to make it work."
Straight-forward process
The 19.5-pt gabletop cartons are supplied by International Paper's Liquid Packaging Div. (Memphis, TN). The supplier refers to them as standard milk cartons, containing paperboard with a polyethylene coating. They're flexographically printed in four colors. The primary version, for large commercial/government users, is mostly brown in color; a green, white and red version sold in lesser quantities for retail is designed to boost shelf appeal.
In the filling process, the Pure-Pak machine pulls a carton blank from a magazine, opening and squaring it, then placing it onto a six-head rotary mandrel. As the mandrel revolves, the carton bottom is heat-sealed as flaps are folded together. The mandrel releases each carton onto a conveyor to the filling station.
The Neotron's no-container/no-fill feature uses computer control to determine if a container is in place for the fill. If the container is present, the computer triggers the auger to cycle product into the open-top carton. The filler uses the company's MicroSet computer control that is said to break down each pump revolution into 200 increments, thereby increasing filling accuracy and consistency.
After filling, carton tops are heat-sealed. Operators manually place 20 cartons into a corrugated shipping case. Palletizing and stretch wrapping are performed manually.
Jensen says the line runs "about sixty percent of the time between mid-February and late September, then only as the product is needed." The product contains nearly 98% pure water, with vegetable gum and food-grade alum mixed together into a viscous gel. A dotted line printed near the bottom of the four carton sides shows the user where to cut away the carton, which is then inserted into the ground near the plant's roots. Bacteria in the soil attacks the vegetable gum within the exposed product, releasing water that's suspended in the gel. The more area of the product that's exposed to the soil, the more water is released.
Jensen estimates that a carton inserted into the ground with just its bottom cut away will last for about 90 days; only 12 to 14 days if planted without the carton. The carton can later be removed from the ground. However, he says it is biodegradable and will break down "after about one wet season." The PE coating, he contends, is so light that it too breaks down.
Future plans
The 1-qt retail cartons are priced at $1.99, only 30¢ per unit more than the 6-oz plastic cups that DriWater has sold sporadically at retail since incorporating in 1990. "We see probably a $10 million market for these smaller cups for use with house plants," Jensen estimates. "Either when people are away from home, maybe on vacation, or for use in winter when heaters remove a lot of moisture from the air."
Sold as singles, or in a paperboard three-pack carrier, the cups are injection-molded of polypropylene by Shapes of Plastic (Seattle, WA). A foil/plastic lidstock is heat-sealed to the mouth of the cup to complete the package.
The cups are filled on a different line than the quarts. "We fill them at about thirty-two a minute," Jensen notes, "but on a piston filler, which isn't a perfect situation. We will eventually change over to a Mateer Burt filler," he states. And why not? The auger filler has already remedied a weighty problem with DriWater's quart cartons. "We've been very pleased with the entire carton filling process," says Jensen. "And the new filler has saved us a substantial amount of money."
