Carton, Board & Paper pumps enter the picture at the end of this process.
Specifically, pumps are used to transfer the finished glue into the corrugating machine, from which it will be spread over the layers of corrugated medium that will be pressed together to form the completed corrugated cardboard sheet and, eventually, the cardboard shipping or storage box. The challenge is cornstarch glue can be difficult to pump because of its adhesive nature, along with its high viscosity. In addition to being sticky and thick, any liquid cornstarch glue that remains within the pump’s internals when it is not operating will harden. In this case, this hardened glue can cause premature wear that will adversely affect the ability of the pump’s mechanical seals/faces and bushings to operate properly. Even worse, when seals and bushings fail, the pump will be prone to leaks, which not only results in lost product – the cost of which can’t be recouped – but also affects operator safety and requires costly cleanup procedures. If a pump’s seals or bushing fail, the choice for the facility operator then comes down to whether the seals should simply be replaced or if the pump should be scrapped and exchanged for a new model. Replacing seals can be easy if spare inventory is on hand, but a pump that has additional performance-dampening damage might require extensive labor and repair costs to get it back to its expected level of performance. In this case, the best option may be to purchase a new pump, though that can lead to longer periods of downtime, which compromises the manufacturer’s ability to meet strict production schedules. In both instances, there may also be a lack of skilled labor readily available to perform repairs or installation, which lengthens downtime.
Therefore, it is imperative that the corrugating- plant operator identify and deploy a pumping technology that has been designed to confront and overcome the various challenges that are ever- present in the handling of cornstarch glue.
THE SOLUTION
Two of the best pumping technologies for adhesives are AODD and internal gear. Specifically, two PSG product brands offer AODD and internal gear pumps that can be used in cornstarch-glue applications.
First, Wilden, whose founder, Jim Wilden, invented the AODD-pumping principle more than 65 years ago, offers clamped and bolted AODD pumps. Wilden clamped metal AODD pumps feature Jim Wilden’s original design, which allows them to be easily installed and serviced with only a single tool. The Wilden bolted metal AODD pump features an enhanced flow-path design that can produce flow rates up to 34% higher than competitive models while offering maximum product containment.
For both the clamped and bolted models, Wilden recommends a ductile-iron wetted path when handling cornstarch glue, though aluminum and stainless-steel models are also available. Operationally, all Wilden clamped and bolted pumps are portable, self-priming, dry run capable and feature no mechanical seals, which reduces the chance that leaks will occur, resulting in superior product containment. They are also easy to operate, install and maintain.
In the realm of internal gear pumps, PSG offers the G Series internal gear pump from Blackmer. The G Series pumps are designed to deliver the durability, flexibility and efficiency needed when handling challenging liquids, such as cornstarch glue. Best designed for cornstarch-glue-handling applications are jacketed cast-iron G Series versions with ANSI flanges, bronze or carbon graphite bushings, with either carbon graphite packing or a Buna-N mechanical seal.
Standard features of the G Series pump include
the ability to create and maintain turbulence-free laminar flow; a triple-lip seal that, in instances of the stuffing box becoming compromised, prevents product leakage; direct replacement- part interchangeability with a wide range of competitive pump models; and a universally designed seal chamber with an oversized heavy- duty bearing housing that can accommodate different sealing technologies.
G Series pumps are standard in many “starch kitchens.” This is because the stuffing-box area on internal gear pumps allow the starch to settle out by displacing the liquid needed to lubricate the seal. The triple-lip seal also provides “dry run” capabilities that help prevent early failure of the seal. Another design alternative is the “behind the rotor” design that positions the seal in fresher product, thus enhancing seal life.
CONCLUSION
A corrugated box without cornstarch glue is just a pile of cardboard sheets, making the adhesive an indispensable piece of the corrugated-box manufacturing puzzle. However, the glue’s sticky properties, along with its high viscosity, make transferring it a challenge, which requires a specific type of pumping technology. PSG offers that technology in the form of Wilden AODD pumps and Blackmer internal gear pumps. Both technologies deliver the design and operational attributes that make them ideal for use with cornstarch glue in corrugated-box manufacturing.
42
July/August 2023
www.convertermag.com
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