Eccentric Disc Pumps Create Product Recovery Cost Savings

As budgets tighten, operators of manufacturing facilities must implement new ways to meet established production quotas while spending less money. Improved operational efficiencies can critically affect the profitability of food and beverage, pharmaceutical, and cosmetic manufacturers, from the most basic production-line level through entire plant efficiencies, and even overall corporate performance. One common solution for this has been increasing the focus to more energy-efficient, “green” operations. This has led to the incorporation of more efficient light bulbs or streamlining operations to reduce the plant’s consumption of electricity, which leads to a decreased carbon footprint. The ultimate goal of these lean manufacturing operations is to realize current or higher product yields while using fewer resources, resulting in a healthier bottom line. Many green initiatives, however, are not driven by sound economic principles. Focusing on improved energy efficiency and consumption in manufacturing operations is admirable, but many manufacturers have already maximized their energy efficiencies. Because of innovative fluid-transfer methods, greater savings than those realized in energy alone can be realized in the food and beverage, pharmaceutical, and cosmetic/personal care industries. Product waste is one area of hygienic manufacturing that experiences extremely high costs. The McKinsey Quarterly Food Waste Alliance reported that, annually, more than $120 billion of product is wasted worldwide. The Natural Resources Defense Council also estimates that the U.S. loses 40 percent of its food from farm to fork to landfills. Between farm and fork are the processing plants that manufacture some of these products. These plants are the focus of this article.

The term product recovery can refer to several different hygienic manufacturing operations—such as improper dosing and product lost through leakages or spills. However, this article will focus on product recovery as it pertains to either raw ingredients or intermediate/finished products that may remain in the suction or discharge fluid-transfer lines at the conclusion of production runs or between product changeovers. Positive displacement eccentric disc pumping technology possesses the line-stripping and product-recovery capabilities necessary to help save hygienic manufacturers hundreds of thousands of dollars per manufacturing site annually. In turn, the food and beverage, pharmaceutical and cosmetic industries have the potential to save many millions annually in recovered—and still marketable and consumable—end products.

Determine High Product-Recovery Values

Three criteria are used to determine if high product-recovery values can be achieved in production processes that directly impact the manufacturing operation’s top and bottom lines:

• Ingredients used in the raw materials for intermediate or final products that are both extremely expensive and valuable
• Product changeovers (switching between products) occuring frequently, such as one or more times per day
• Appropriateness of the product-recovery technique or technology for the ingredient or product

Many critical areas exist within a hygienic-manufacturing operation in which fluid transfer is required. However, many manufacturers are wasting these expensive materials when they do not optimize their product-recovery capabilities, which can be accomplished through the use of eccentric disc pump technology.

The Challenge

Incorporating increased energy efficiency into the hygienic-manufacturing process is one way to save operating costs, but it is not necessarily the best way. Table 1 shows how much money is consumed and potentially saved per positive displacement pump if the cost for energy is $0.10 per kilowatt hour (kWh). The sum of $1,008 is the energy cost to run the pump annually. If the energy consumption was reduced by 20 percent, which is unlikely, it would represent a savings of almost $202 per pump per year. For a comparison, Table 2 shows a conservative example of how much can be saved when using positive displacement eccentric disc pump technology with a minimum product-recovery capability of 70 percent to transfer a finished product from a feed tank to a filler. When product-recovery savings of $32,160 are divided by power savings of $202, the product-recovery savings is 160 times higher per pump. The product-recovery savings accumulated in one year in this example will pay for 32 years of energy to operate the pump (not including interest). This is a huge opportunity for the manufacturer. Within today’s pumping technologies, little room exists to improve motor efficiency—especially not by 20 percent. However, product recovery can be improved. Less obvious savings exist, too. When transfer pumps cannot adequately strip suction or discharge production lines, a snowballing effect occurs on the costs that are incurred by the facility operator. Ancillary costs can include:

• More water to clean the lines
• Additional cleaning and treatment chemicals to clean the lines
• Sanitizing chemicals to sanitize the lines
• Energy to facilitate the cleaning process
• Labor costs/hours to perform longer cleaning operations
• Disposal costs of used water, chemicals and product
• Water treatment costs and associated treatment chemicals

Product waste is a severe handicap to the manufacturer’s bottom line, and product recovery is an opportunity to limit the waste and gain cost savings. Wasted materials or end products mean that the manufacturer cannot monetize usable product that is washed out of production lines and disposed. For many years, the go-to technologies for hygienic manufacturing processes in the food and beverage, pharmaceutical, and cosmetic industries have been lobe, external circumferential piston (ECP), centrifugal, hose and progressive cavity-style pumps. While these technologies perform the basic pumping task, because of their design and operating principles, lobe and ECP pumps, for example, do not possess the ability to adequately strip suction or discharge lines. This is a critical consideration for industries that may use the same pump to transfer different products in a hygienic operation. Traditional pumps also wear constantly, which increases their internal clearances with time, resulting in product slip, and reducing flow capacity and volumetric efficiency as operating pressures and fluid viscosities vary. Specifically, lobe and ECP pumps have two shafts that must be sealed, which doubles the number of areas where leaks can occur. Lobe and ECP pumps are also not self-priming and can only run dry for a short period of time, unless they have flushed double-mechanical seals. These pumps will also experience diminished performance when handling low-viscosity materials. Many manufacturers who rely on these types of pump technologies are also often forced to use them in conjunction with so-called “pigging” systems, which use a projectile to push out the residual product. While well-installed pigging systems deliver the highest recovery rates in product line runs without interruptions (with no heat exchangers, valves, filters, flow meters or other accessories needed), great care must be taken to ensure that purified compressed gas or air is used to push the pig, which can be challenging for maintaining product purity.

The Breakthrough

With the amount of potential savings achieved with adequate product recovery, eccentric disc pump technology sets a new standard in product-recovery capabilities in hygienic manufacturing operations. Eccentric disc pumps are the only hygienic pumps with this capability. The key to the eccentric disc pump’s heightened product-recovery capabilities is that it operates with a disc that moves on an eccentric plane within a circular channel, which gives the pump the ability to provide non-pulsing, low-slip operation with high volumetric consistency. Many liken this method of operation to a scroll-compressor effect. This design also means that flow rates vary minimally with changes in viscosity, temperature, system back-pressure and component wear. Most important for product-recovery considerations, eccentric disc pumps are efficient enough to pump air when no fluid is present. This creates a vacuum effect on the pump’s suction side and a compressor effect on the discharge side. Once the product runs out in the feed tank, the eccentric disc technology continues to pump air in a constant, non-abrupt, non-pulsating manner so that the surface tension on any remaining fluid is not broken. This produces a plug effect, which pushes out the product “plug” as a whole. Because the eccentric disc pump transitions to the purging process by using the air that is already in the feed tank, no problems with maintaining product purity should occur. If a problem does occur, then the air/gas that blankets the product in the tank should be further purified to start. This method of product recovery is a much safer and cleaner alternative to pigging or a simple air/gas-blowing process. It is also much more difficult and costly to ensure the proper quality of required air/gas that is sourced from compressors or high-pressure bottles. Despite these drawbacks, some processors have adopted a hybrid recovery processes for high-value products using both eccentric disc pumps and pigging. The eccentric disc pump is used to automatically recover most of the product from the line into the packaging equipment and maximize product recovery on sections of the line that pigging cannot serve. The pig is then used for a secondary recovery process to recover final product that adheres to the tubing wall in “piggable” sections of the line, such as prior to a clean-in-place operation. The advantage of using eccentric disc pump technology for product-recovery operations is that the typical amount of product recovered is more than 95 percent on the suction side of the pump and typically 60 percent to 80 percent or more on the discharge side. Examples in which eccentric disc pumps are incorporated in hygienic product-manufacturing operations that have resulted in documented six-figure savings per pump line include:

• A multinational, high-end cosmetic manufacturer recovered enough silicone-based product to immediately pay back the cost of the pump within a few short days.
• Two global yogurt companies with long transfer lines recorded 70 percent to 80 percent and higher product recovery rates, which resulted in the quick deployment of an additional pump in the process.
• An oral-care company upgraded from centrifugal pumps to quickly achieve product recovery targets with its low-viscosity products.
• A pharmaceutical company filled many oral medicines with frequent product changeovers.
• A large baked-goods company more effectively recovered the filling used in pastries, which also prevented injection nozzles blockages.

When used in hygienic-manufacturing operations, the eccentric disc pump serves first as the normal process pump, with the product-recovery capability as an added benefit. For other pump styles, product-recovery hardware, such as pigging systems, is a considerable cost and adds unnecessary complexity to the pumping operation. Specific additional advantages of eccentric disc pumps in product-recovery applications when compared to other product recovery methods include:

• Eccentric disc pumps can recover product from tank bottoms, inlet and outlet lines.
• Eccentric disc pumps can recover product from small-diameter lines where pigging is not possible.
• Eccentric disc pumps can recover product through ordinary valves, heat exchangers, magnetic traps, flow meters and other accessories found in the transfer line.
• Product recovery with eccentric disc pumps is seamless because no line interruptions will occur between normal production and the product-recovery phase.
• For the majority of the product-recovery process, air mixing is not a concern because most of the product recovered by an eccentric disc pump comes in the form of a product plug with no air mixed in. A simple flow switch can be used to shut down the pump before the air purge reaches the product’s destination.

Conclusion

Operating cost reductions in a manufacturing facility will continue to be a front-of-mind concern for plant managers. Initially, cutting energy costs was a popular way to attack the problem. However, the overall value of that approach to the manufacturer’s bottom line may have been maximized. Operators of food and beverage, pharmaceutical, and cosmetic manufacturing facilities that rely on hygienic systems should develop ways to optimize energy costs. They should also determine how much cost savings can be realized in targeted product recovery. Per-pump product recovery cost savings can be as much as 32 times greater than the yearly cost of the energy needed to run the pump. In a large production operation, this recovery can result in savings of millions of dollars per year. The pump is critical in optimizing product recovery that is used to transfer raw materials or finished products through the suction and discharge lines. While lobe and ECP pumps have been popular choices, they feature several operational inefficiencies that mean optimized product recovery will not be realized. Eccentric disc pump technology is a solution, that, by nature of its operation, offers the line-clearing and stripping capabilities that offer advantages when compared with other pump technologies.