Holding Patterns
by Lynn Petrak
Tanks and tubing systems are designed for volume, sanitation and durability needs.
At a first glance inside a dairy plant, it may not seem like tanks and tubing systems have changed all that much in recent times.
Vessels are still vessels and they are still used at several points in a processing facility, from holding liquids after receiving to mixing and blending during processing to storing pasteurized milk and powdered products.
Tanks remain versatile, in that they are used for the full range of dairy products, including milk, cheese, yogurt, ice cream, whey and powdered products, and can be used for the agitation of liquids and powders in small batches as well as for large-scale product storage in the form of silos. In some facilities, tanks truly haven’t changed at all, since they are the same ones that have been on the floor for 20 to 30 years.
Tubing, too, is still used for the straightforward function of moving liquid or air from one point to another. Although piping for processing and other purposes often has a shorter life span than tanks, such systems have traditionally been built to last.
An up-close look at newly installed processing, mixing and storage tanks and tubing systems in dairy settings, though, shows that there have been definite changes in tank and tube design in recent years, driven by regulations, safety precautions, volume adjustments and product diversification, among other factors.
For one thing, composition isn’t the same as it used to be. “Materials have changed and we’re using different specialized materials. Some [processors] have gone to better grades of stainless,” says Paul Hume, national sales manager for processing systems and equipment at Paul Mueller Co., Springfield, Mo., which supplies dairy customers with single-wall tanks, horizontal tanks, processing and pasteurization tanks, silo storage tanks and smaller, portable Porta-Tanks, among other offerings.
While many tanks are constructed with Type 304 or Type 316 stainless steel, Hume says, some dairy operators have upgraded to materials like Type 2205 stainless and AL 6XN alloy.
Meanwhile, although most tubing and accompanying fittings are stainless construction, the use of silicone as a material has emerged over the past few years. CPS Limited in the United Kingdom, for example, now offers high-strength silicone tubing designed especially for dairy applications. In the United States, the AdvantaPure division of New Age Industries, Southampton, Pa., supplies colored silicone tubing for fluid and air transfer in several industries, including dairy.
Another notable trend in tank and tube design lately has been processors’ need for systems that can accommodate their burgeoning production capability. According to John Fearn, director of sales for New Lisbon, Wis.-based vessel manufacturer Walker Stainless Equipment, volume is a key driver when it comes to new tank orders from dairies. “A lot of people, especially with consolidation, are getting through more with less, and they are increasing capacity,” he observes.
Likewise, supplier CPS Scherping (part of Charlotte, N.C.-based Carlisle Group of Companies, along with Walker Stainless) is fielding more inquiries from larger dairies about its range of tanks, including balance, flavor mix and cheesemaking tanks. “Most often, we hear from a plant that is doing an upgrade and they need bigger tanks and bigger equipment, because sometimes they don’t have the right size,” says Dan Dickhausen, engineering manager for Winsted, Minn.-based CPS Scherping. “We make the range of tanks for small ones up to 6,000 to 7,000 gallons.”
Hume agrees vessel sizes are getting larger as a result of higher volumes. “We are building tanks larger for increased capacity,” he says. In fact, he notes, one cheese company with whom Mueller works recently invested in larger tanks to accommodate the 15 million pounds of milk that now pass through its facility every day.
Volume has an impact on tubing as well. To meet higher flow requirements, tubes come in a greater variety of sizes and are constructed to withstand greater throughputs.
In addition to installing larger tanks and wider and longer tubing, many dairies that are boosting volumes are also using more pieces of equipment, especially manufacturers that are expanding their operations and product lines to stay competitive. “The business is somewhat cyclical, but I’d say we are selling more equipment than we’ve previously done,” says Hume, citing major plant expansions by leading ice cream manufacturers that have broadened their product lines and grown into firms with a true national and global reach.
Controlling Forces
Tanks and tubing may have straightforward functions for respectively containing and moving through products at various points in the system, but they also reflect today’s tightly controlled operations.
Indeed, because volume and flow — and the loss thereof — translate into the bottom line, precision is as important with the use of tanks and piping as it is in other steps in the production process. To that end, there has been an advent in high-tech, computer-based controls that are used to run and monitor tanks and flow. “Systems are becoming more automated and we do offer instrumentation,” Hume says, adding that dairy processors have embraced technology that helps improve efficiency and accuracy while keeping a lid on labor costs.
Just as operators work to ensure accuracy, they want to do what they can to make the finished items as safe as possible. As with other equipment used in dairy facilities, tanks and tubing are a focus of safety efforts.
That’s why modern tanks and tubes are constructed with stainless steel that is easily washed down and come with options for clean-in-place (CIP) features. “Cleanability is a must for longer shelf life,” Hume says.
Dickhausen, too, says CIP systems continue to become more mainstream in dairy applications. “It’s been pretty steady, and it’s gone along with process piping as well,” he says of CPS Scherping’s requests from dairies.
Fearn, for his part, reports that sanitation is among the top priorities of those who purchase new tanks. “Pretty much everybody is using CIP, though there are some people who want to manually clean their kettles,” he says.
The combination of sanitizers and frequent washdowns can take a toll on any piece of equipment, including tanks, which is why proper care and maintenance are key to the life span of vessels and accompanying piping,. “We have vessels in the field that are 40 years old and we have other people who will ruin a vessel in a year,” Fearn explains.
New and Improved
Although changes to tank and piping designs are more on the subtle than the dramatic side, suppliers do update their equipment for optimum performance.
Fearn, for his part, reports that R&D work is done on an ongoing basis at Walker Stainless. “I can’t say it is anything ultra revolutionary, but we are perfecting existing techniques to improve production efficiencies,” he says. “We are doing a bit of design tweaking and more layouts of the manufacturing process for ergonomics.”
Also indicative of today’s need-driven manufacturing climate, in addition to choosing from a spectrum of processing, mixing and storage tank models and tubing options, dairies can also install custom equipment and materials that fit their particular needs. Walker Stainless, among others, offers custom-built sanitary and industrial models, such as aseptic storage tanks, blend tanks and single-shell tanks.  
Lynn Petrak is a freelance journalist based in the Chicago area.