Innovations in batching, dosing and weighing

By Dave Harrold, co-founder of the AFAB Group

BATCHING, dosing, and weighing seem like simple, straightforward production operations. Set a target value, open a valve, measure the material, and close the valve when the measured value matches the target value. Of course, we all know nothing is ever as simple as it seems.

We asked users who spend their days working in the consumer products, food, pharmaceuticals, and wine production industries to share their batching, dosing, and weighing challenges. A few asked that we not use their names, while some others asked that we not include their company names, but rest assured that these are companies whose products you know well.

Next, armed with our newly created and somewhat unexpected list of challenges, we talked with hardware and software manufacturers to learn what products and technologies they have or are developing that can help users overcome some of these challenges. These challenges and the solutions are eye opening.

Heavy Challenges
Anyone who has dumped a bag of dry solids, say flour, into a container has experienced inconsistent product flow, product hang up, and dust-control issues associated with that transfer. Now introduce bulk storage tanks with vibrators, piping, scales, valves, mixing vessels, dust collectors, and environmental influences, like humidity, and you can begin to appreciate the challenges of making accurate, repeatable, dry solids additions at places like Washington Quality Foods, a producer of Dolly Madison and Tasty-Kake products.

Tony Murray, Washington’s director of information technologies, explained that it uses a lot of sugar, salt, dextrose, six grades of flour, and more than 300 other ingredients to produce cake, muffin, waffle, and other dry-food mixes.

“When we decided to build a new plant,” Murray says, “we faced the typical challenges of moving, measuring, and dispensing dry products, but we also wanted to resolve two additional challenges: determine which ingredient additions could be fully automated and which were best served by a software supported manual process, and improve our kosher-validation processes.” All of Washington’s products are kosher validated. This means food is prepared in accordance with Jewish dietary laws, and a rabbi verifies that appropriate ingredients, as well as strict handling and cleaning procedures are being enforced.

	FIGURE 1: MIX IT UP
	A field operator makes a manual addition to a vessel at Washington Quality Foods.

”We analyzed about two years of historical data,” Murray says, “and determined that 18 of the ingredient additions could be fully automated with the remainder being best served by software supported manual weighing and dispensing procedures.” The solution was to use Wonderware’s InTouch software to handle both automated additions, and enforce a series of interactive operator prompts for manual additions.

“Cosmetic, custom food, and pharmaceutical producers share a lot of the same challenges. These include using lots of different ingredients, making gram-sized dosages, ensuring ingredient confidentiality, maintaining personnel and material safety, minimizing waste of high-value products, and ensuring production facilities perform as efficiently as is possible,” says Yves DuFort, with Invensys/Wonderware. He adds that ingredient confidentiality and gram-sized dosages concern several industries, so it’s common to repackage ingredients into generic containers, and then develop barcodes that indicate ingredient, source, and lot. These ingredients are stored in secure, central weighing and dispensing facilities, similar to a pharmacy.

“When a specific product (recipe) is to be produced,” DuFort says, “employees in the dispensing facility pre-weigh and package the individual ingredients and produce a new or second barcode that augments the content of the original barcode with such things as the scales used, actual weight, date, dispensing personnel, etc. These are all the things that need to be part of the batch history to meet kosher and/or regulatory requirements.”

Once production begins, software prompts the operator when it’s time to make an addition, helps enforce any required personal protective measures, and uses the barcode information to validate that the correct ingredient is being added at the appropriate time. For automated ingredient additions, software helps ensure accuracy, efficiency, and repeatability by binding specific pieces of equipment such as scales to all iterations of a particular recipe, and informs operators as soon as a transfer path becomes available for cleaning.

Jim Wiesler, who works for a major pharmaceutical firm, says he has talked with his peers at other companies, and they agree that the challenges associated with both dry solids and liquid-ingredient additions are very similar to the challenges expressed by Murray and DuFort.

However, Wiesler adds, “Another really big challenge is getting the product experts, the scientists, to establish ingredient target values with a proven, acceptable over and under-target range. For example, when we begin taking a product from the laboratory to production, the scientist may tell us we need to add ‘exactly’ 1,000 liters of high-purity water—not 999 liters and not 1,001 liters. Sometimes we’re able to talk through the reasons, and eventually establish an acceptable target range. For these additions, we’re able to apply automation. For ingredient additions that the scientist insists must have a zero or near-zero target range, we apply manual methods of measuring and dispensing, and accept the allied costs and production impacts that manual intervention creates.”