Penglai Huande Steel Valve CO., LTD.

Food And Beverage

The industry looks bright. But those who deal with it face issues about who regulates what, and they are starting to see competition from overseas.

According to FoodProcessing.com, budgets in 2010 for capital expenditures in the food and beverage processing industry were up more than 19% over what they were in 2009, when actual spending declined by about 8.7%. And research by Industrial Info Resources, released in late November, revealed an even more dramatic improvement when comparing U.S. and Canadian projects tracked in 2010. The number of projects increased 42.5% from 2009 (359 projects) to 2010 (510); investments increased a very healthy 53.8% from 2009 ($3.58 billion) to 2010 ($5.51 billion). The industry is clearly in the throes of recovery and does not appear to have suffered as much as some other manufacturing industries from the economic collapse.

food

That's good news for those who work in, and supply to, food and beverage processing plants, including those companies that provide the valves or buy the parts that keep the plants running smoothly. But there remain some challenges that must be addressed, including new safety concerns that may lead to changes in material requirements, as well as potential competition from overseas.

Valves used in the food and beverage industry can be divided into two major groups: those in direct contact with food materials and those handling utility services (steam, water, etc.). While there are regulations applying to both, those for the first group are more stringent, since they involve direct contact with food.

On the food-contacting side, things are regulated by standards from various independent organizations: 3-A Sanitary Standards, Inc. and NSF International, the Food and Drug Administration (FDA) and more. The inside of the valve, for example, must be smooth enough to avoid trapping particles of food or allowing bacteria to accumulate; this usually translates as 15 to 20 microinches arithmetical mean roughness (Ra).

Any soft material in the valve, adds Karl Lutkewitte, product manager at the Steriflow division of Jordan Valve, must meet similar roughness criteria, and must not absorb or hold the product going through the valve. There also should not be crevices where material can be trapped to later decay, nor should there be a dead volume in which there is no movement, thereby allowing the material to stagnate.

Most food-contacting valves are made of 316 stainless steel for corrosion resistance (or 316L if the valve has welded end fittings), Lutkewitte says, although other alloys are used for certain applications. In the pharmaceutical industry, which uses valves similar to those used in food transference and faces similar challenges, there also may be restrictions on the ferrite content of the 316 (including use of 316L) to help prevent rouging, which is an accumulation of iron oxide, hydroxide or carbonate on the inside of valves, tubing or vessels (resulting in colors ranging from red to black). Rouging "is viewed as a potential place where microorganisms—bacterial, virus, biofilms—can make a home," says Lutkewitte. "It's thought that if you minimize that ferrite content to no more than 3%, you minimize the probability that rouging will occur."
Another important difference between general application valves and those made for food service is that the food-related valves tend to be forged or machined out of bar stock, rather than cast. "Castings are frowned upon [in food service]," says Lutkewitte, because they are more likely to have pores, while "forgings are more dense with no hidden cavities in them."

In some areas, the requirements for food valves are less stringent than for those used in other industries, Andy Butcher, product market manager, Spirax Sarco, points out. One reason is that the pressures involved tend to be lower, and aside from the chemicals used for clean-in-place (CIP) operations, they're not subjected to some of the highly corrosive services of industries such as chemicals. "On the utility side, where we're controlling, for example, steam going to a heating vessel, they tend to be general service control valves,” Butcher says. With fairly low-pressure, low-temperature steam going through them, such valves will generally be made of cast iron or carbon steel, he continues, although some companies elect to spend the extra money and use stainless.

Still, those CIP chemicals can be a challenge, according to Wayne Labs, senior technical editor of Food Engineering magazine, who wrote an Oct. 1, 2010 article entitled: "Tech Update: Clean-in-Place Equipment." CIP chemicals are becoming stronger, that article says, and this has led some valve makers to use AL-6XN, a corrosion-resistant, iron-based, austenitic stainless alloy, in place of 316. There also are claims that AL-6XN is more resistant than 316 to certain forms of rouging.