Considerations For Custom Conveyors
Mon, 08/25/2008 - 6:27am
Material transfer is an integral part of any operation. When increased production demands and new product lines challenge a processing line, those in charge of optimizing production must evaluate myriad factors to determine the best method for moving chemical ingredients.
To eliminate wasted production efforts, manufacturers are moving from conventional methods into more automated processes using pneumatic conveying technology.
Pneumatic conveying systems are customized based on three principal factors:
Edward Dodge, operations manager at Helena Industries’ Cordele, GA plant agrees. The plant uses a range of process technologies to manufacture, formulate and package herbicides, fungicides and insecticides. “We had a unit that started to get a lot of business,” says Dodge, “and that is why we started looking at different transfer systems.”
Perhaps the most important aspect of choosing a pneumatic conveying system is determining the primary goal you wish to attain. These systems can increase productivity, solve safety and hygiene problems, reduce costs, increase flexibility, eliminate contamination and a host of other issues.
When increased demand turned up the notch on production at Helena, the company’s primary goal was to eradicate an ergonomic issue by removing the need for workers to dump 20 to 40 drums (that weighed up to 225 pounds each) containing powder chemicals from a raised platform.
Although the job required a single operator, Helena staffed it with two. “We haven’t had any injuries, but it was always potential. And we have tried to go through the plant and kill any potential we have with ergonomics,” stresses Dodge.
“We tried a bucket elevator, and it was terrible because it created a lot of dust in the air. And we still had some ergonomic issues with overexertion when dumping the product into the elevator.” In an attempt to yield results from the bucket elevator, several speeds and discharges were tested.
When the drawbacks for this application proved insurmountable, Dodge considered a hoist system. However, that would have required operators to do some drum handling, making the process significantly slower than the existing method.
That's when Dodge contacted VAC-U-MAX, a supplier that designs and builds custom pneumatic conveying solutions.
“They had the best understanding of what I wanted to do,” he says. “I didn’t have to spend a half hour trying to explain why I was transferring and how I was transferring it—they were well educated in that area.”
An understanding of material characteristics is essential when designing a pneumatic conveying system. Commonly, there are several product grades within the same group, and those forms may be free flowing, sluggish or non-free flowing. For instance, one grade of zinc oxide may have the consistency of talc, while another is more cohesive, thus sticking to the sides of conveying tubes.
When cohesive materials are used, solutions like high-polish finishes applied to the system interior may be appropriate to reduce the possibility of packing inside the line. Since pneumatic conveying systems pull material through the tubes vs. pushing, they are suitable for most materials and can be customized regardless of the characteristic.
“That is what we like about these units—they are flexible. If you want speed, you can build up the system; if you want to eliminate a hazard, you are able to do that and not have timing be an issue,” says Dodge.
The size of the pneumatic conveying system depends upon the desired speed at which product is transferred from one place to another, as well as the distance between two transfer points. In order for Helena to move several hundred pounds of material in 30 minutes, a VAC-U-MAX MDL105017T tube hopper was utilized to transfer claylike material up a level into a volumetric feeder. Another MDL015017T tube hopper, which pulled granular material from awkward-shaped drums weighing more than 200 pounds each into a liquid mixing tank, was also added to a separate line.
Although the time to transfer the products stayed relatively the same with the new units, the jobs went from requiring two people to a single operator. “We weren’t looking to cut any people, but we did save some money by it. We actually paid for that first piece of equipment in one year,” according to Dodge.
Vacuum systems can help improve production capacity. For high-volume products, systems can be designed to pneumatically load material directly from silos for a faster rate of speed.
Many manufacturers have additional concerns that also need to be addressed outside of the primary goal. Helena Industries, for instance, was concerned about cleanup between different runs on the line, and wanted to be sure that the equipment could be taken apart easily and put back together again without sharing contamination.
“We don’t need to send a maintenance man down to take it apart. Our operators who run the equipment can easily take it apart and clean it and reassemble it, and you don’t need a special tool,” Dodge says.
Dodge is also pleased with what he calls bonuses from the vacuum system, such as minimizing environmental dust exposure and improved housekeeping, because the drums no longer need to be inverted.
Dodge exclaims, “It was one of those rare instances when you spec something over the phone and e-mail, bring it into the plant and have it look like you thought it was going to, and install and work like they said it would. It doesn’t get any better than that.”
n ?Dodge contacted VAC-U-MAX, a custom pneumatic conveying solution supplier, when belt elevators and hoist systems failed.