Precision performance is extremely important when it comes to filling dry products for the food industry. If your application calls for filling containers with 425 grams of product, that amount needs to be in each container. Inaccurate fills can result in lost revenue from product giveaway, and loss of credibility in the eyes of your customers.
The best way to ensure your machine’s performance is through pre-installation testing. While most reputable suppliers do offer to test their machines for customers, the manner in which they do test varies wildly. The purpose of this article is to illustrate the importance of pre-installation testing, and demonstrate the manner in which specific areas being tested, such as product in-feed, product flow, cutoff, dust … and even the test laboratory itself … all play critical roles in determining the accurate performance specifications of your filler.
Rationale for Pre-Installation Testing
A common question people ask is: How accurate will their new machine be? That question can only be answered after the machine has been properly tested. It is impossible to quote accuracy without knowing all the parameters of the project. That’s because accuracy is affected by several factors, such as the product itself, the type of container that’s being filled, fill size and fill speed — all of which contribute to the overall accuracy rate. The only way to effectively quote accuracy is to test product and machine in a test laboratory.
The goal of a pre-installation test is to replicate, as close as possible, the actual environment in which the fill will be operating in your facility. Conducting tests this way provides results that give a fairly precise view of how accurate the fills will be when the equipment is operational in a facility. The best testing results are seen when conditions most closely mimic your actual environment. This eliminates variables that can affect the outcome. And one such variable is hopper pressure.
Most fillers operate in plants with a constant stream of raw material (or product) that’s constantly being fed into the hopper. The more product that’s in the hopper, the more it weighs, and that pressure can affect the accuracy of the fill. That’s why it’s important during the testing process to have an in-feed system that provides a constant supply of product, i.e., trying to best replicate how the product is going to be fed into machine in your facility.
To accomplish this, Spee-Dee installed a multiple in-feed system with horizontal in-feed screw bucket conveyors and a pneumatic conveyor to use in its test lab. The objective is to learn exactly how the product is being fed into the machine, how it flows through the hopper and into the hopper. Using an in-feed system helps supply product to the hopper at a consistent rate, and keeps product at the same height and pressure in the hopper throughout the test. By feeding a steady stream of product into the hopper, Spee-Dee is able to perform longer test runs at actual speed to gain more reliable and accurate data.
Many filler manufacturers don’t have an adequate in-feed system, much less the needed room to install one. A filler machine that’s outfitted with a bagger and in-feed system can be 12 feet high or more. Some vendors test their machines by having an employee hand-feed product into the hopper. While the weight and pressure of product in the hopper can be matched for a few seconds at the start of the test, it cannot be sustained for any meaningful length of time by having an employee scoop product into the hopper. This leads to unreliable results, as the weight and pressure of product doesn’t come close to matching your actual application throughout the duration of the test. Conducting a test for at least five minutes is crucial to obtaining real-time data on the fills and calculating accuracy rate for your specific application.
Another area that’s being tested is the product itself. Characteristics such as its density, consistency and they way it flows are all evaluated in how it interacts with the filling machine. Temperature and humidity can also alter the product and affect the fills. Some products retain moisture more than others, which can change density throughout the day in a humid environment. These are variables that admittedly are difficult to replicate in a test lab, but need to be considered in the overall testing process as they all factor into the goal of trying to achieve accurate test results.
Product Cutoff and Dust
Proper testing also asks the question: Can we stop the product after the fill? If an auger is filling 90 pouches a minute, then it needs to stop the flow 90 times each and every minute.
Just a little drip of product landing in the seal area of a pouch or package can compromise the integrity of the seal, which leads to product leaking and premature spoilage. Furthermore, dripping product looks sloppy and unprofessional, and reflects poorly on the brand. Additionally, each drip is lost revenue; a small drip may not seem like a big deal, but it does add up over time. It’s important to select a filler with the proper tooling to help eliminate product drip. That’s why pre-installation testing is the perfect time to catch any drips, and make the necessary adjustments to ensure product flow stops with each fill.,
Dust is another component examined in the testing process. Some powders, such as powdered drink mix, are extremely fine and cause dust during filling. Excessive dust may need to be captured as it can affect the sealing process.
When completed, test results including filling accuracy, speed and test parameters provide an accurate assessment of how the filling system will perform in your facility.
Every filling machine needs to be properly tested prior to installation. Testing gives assurances that the machine will meet your filling specifications. Many simply want to know how fast and accurate their machine can fill during a production run. But arriving at those results involves evaluating several factors of the entire filling process – and that can only be done in a professionally designed test laboratory. Testing strips down and removes all the guesswork and unknowns of the filler – leaving you with solid, valid data and peace-of-mind that their filler will perform as expected. That’s the value of per-installation testing.
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