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Centrifugally cast components help drive decanter centrifuge success

Centrifugally cast components help drive decanter centrifuge success

You don’t become a global leader in centrifuge technology without machines constructed of the most advanced materials. That approach, among others, is what has propelled Centrisys Corporation to success as a leading U.S. manufacturer of decanter centrifuges, dewatering systems and dewatering technologies for municipal and industrial applications.

Centrisys’ machines use centrifugal force to separate solids from liquids and recover various resources for its customers around the globe. The company sources parts for these machines from U.S. suppliers, the majority of which are located within a short distance from its headquarters in Kenosha, Wis. This helps ensure quality control and a robust inventory that’s always stocked for any customer needs.

“We partner with strategically minded suppliers given the need for us to hold down capital costs and supply our customers with products that deliver low lifecycle costs,” said Centrisys Purchasing Manager Allen Horochena.

Spuncast, Inc., is one supplier that has proven to be a true strategic partner to Centrisys over the years. Spuncast, a custom supplier of high-quality centrifugal castings, manufactures the bowl shells and scroll shafts used in Centrisys centrifuges.

One-piece construction pays off

As wastewater enters one end of the centrifuge, it passes through the centrifuge bowl, which rotates at an extremely high speed. This separates the solids from the liquid, and the clarified water exits from the opposite end of the machine. A key feature that differentiates a Centrisys centrifuge is the fact that the bowl shell is centrifugally cast, as opposed to being rolled and welded plate.

In a rolled and welded bowl shell, a metal plate is roll-formed into a tube and the joint is then welded. For some applications, this is a standard practice and the end product is suitable. In the case of centrifuges, however, this method is less desirable. The reason is that the inside of the bowl normally rotates at about 3,000 Gs, subjecting it to extreme conditions. While a rolled and welded bowl shell can normally tolerate those conditions, it may run less efficiently due to less-than-optimal balance.

“Welding is never going to be 100 percent pure,” said Centrisys Director of Engineering Luis Garza. “Even if it looks like a perfect weld, it’s always better if the tube is one homogenous piece of steel.”

That one-piece construction is what centrifugal casting delivers. In this process, molten metal is funneled into a rotating die. The rotation of the die creates centrifugal force, which thrusts the metal toward the die wall. Centrifugal castings use directional solidification and pressure from the centrifugal force to create castings with a dense, pure structure – a process that also delivers consistency from part to part.

Maintaining the balance of a centrifuge under the force of its high-speed rotation is critical to keeping it running effectively and safely. Centrifugally cast parts aid in this process because they are inherently round and do not distort into an oval under stress. This is also one of the keys to Centrisys’ improved efficiency over competitive decanter centrifuges.

Right material choice ensures durability

Spuncast also worked with Centrisys through the materials selection process, leading to the right materials choice for the demanding application.

Centrisys’ scroll shafts and bowl shells use duplex stainless steel. Available in alloys of 2205 (CD3MN) and CD4MCu, duplex stainless alloys give the centrifuges unmatched durability and minimal maintenance requirements.

“Quality and cost really go together with Spuncast,” said Centrisys Purchasing Assistant Christine Smith. “Spuncast’s quality helps us keep our costs low and helps us be more competitive in the marketplace.”

Centrifuges must operate in demanding environments for long periods of time, and the right material goes a long way in maintaining lifecycle cost and longevity. Every Spuncast part that Centrisys receives comes with a material certification that documents its chemistry and mechanical properties. Additionally, duplex stainless steel is corrosion resistant, standing up to the harsh chemical environments of the liquids passing through each centrifuge.

Emphasis on quality = on-time delivery

Since Centrisys’ machines are individually assembled, quality is key. And Spuncast consistently delivers exacting parts that fit the tight specifications that Centrisys requires.

“Spuncast has a good reputation for being on time and on spec,” said Garza. “We know that we can grab the center section and just put it together without any surprises, which enhances our ability to deliver on time.”

This focus on quality has produced a strong relationship between Centrisys and Spuncast. The end result is a highly reliable and robust Centrisys decanter centrifuge that delivers superior performance.

A win-win formula

Relationships go a long way in manufacturing, and Spuncast has proven it will go to extra lengths to support Centrisys, whether it’s normal business hours, or stepping up in an emergency at any time. The fact that Spuncast is based in the U.S. and dedicated to U.S. standards of quality makes it a perfect solutions provider for any manufacturer in need of centrifugally cast components.

Smith says she is particularly appreciative of the company’s quick responsiveness.

“We have their cell phone numbers and they get back to us right away, no matter the issue or time of day. The consistency and integrity that Spuncast brings to the table in virtually every aspect of these vital components of our products results in a win-win for our company and our customers.”

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