which is where the coolant (glycol) circulates. Previously assembled by hand using GMAW, this automated method will mean fewer openings to seal, enable reliable repeatability, and save time. Inspection Importance Supervisor Casey Antonick is in charge of quality control and also trains new welders. “What’s inside the tank represents lots of money for customers, so contamination can’t happen,” Antonick explained. He described the in-house inspection process as vigorous. A quality control checkpoint management tool is used to ensure what’s built meets company standards. There are different criteria on a tank’s inside and outside, for instance, that must be acceptable. Several assessments take place during the construction process. “Those are mostly visual,” Antonick added. Currently, MCF is in the process of achieving ASME Boiler and Pressure Vessel certification. “We look for pit-free welds and have rigorous inspections for pinholes, pits, cracks, and inclusions, as they lead to bacterial contamination,” Frye continued. Procedures include penetrant and ultraviolet porosity tests, visual inspections, and making sure edges aren’t sharp. Mechanical stress and load limit tests take place on structural parts in the weldment stage. On cooling jackets, air and hydrostatic tests are made at different pressure capabilities for several hours. The same goes for testing shells, where tanks are filled with water and pressurized to ensure there are no leaks. Finishing Front In the beverage industry, ultrafine finishes are of the utmost importance on a tank’s interior, because that’s where beer ingredients and liquid are held before consumption. Ultrasmooth blending and deburring must occur so there are no metal shavings, which could result in bacterial contamination. “All welds need to be free of porosity to be finished to a sanitary level,” Frye added. Fitup and preparation are critical factors in GTA welds, which get ground to 150-grit or more. It’s also preferred for the outward appearances to look just as good and seamless. “Extra time is taken to apply an aesthetic finish to the outside of tanks. The polishing is all by hand,” Frye said. Providing Project Management, Sales Support Marianna Huntley is project manager. In this role, she manages all customer interactions, sets expectations, and coordinates the tanks’ production schedule, which is organized in her office on a massive board. “Projects can take three to six months. It depends on the job size,” Huntley said. She keeps open lines of communication in quoting lead times and providing status updates. Sales and Marketing Director Liz Shearer creates proposals each week to meet specific brewery needs, including long-term goals, and gets in touch with many departments for estimates. “We work with award-winning brewers. That’s a real honor,” Shearer said. Installation Impact In the United States, tanks get from the shop to their new homes by semi tractor-trailers. During the winter, accordion covers might be used as protection from salt on snowy roads, but the rest of the year there are no tarps because they can mar finishes and have iron particles that can cause rust. For installation, certified riggers and equipment operators are employed. Customers’ architects, electricians, construction contractors, steam fitters, and refrigeration technicians are also part of the process. In addition, purge GTAW is used for on-site process piping of stainless steel. This is most common between brewhouse vessels, given there’s a need to transfer liquid from one tank to another. Brewing Process Specialist Waylon McAllister assists customers with new tanks and choosing the right equipment. Locally, he goes on-site to make sure everything is set correctly and handles inaugural brews, but for big projects, he will travel. He also emphasized cleanliness. Owners need to first passivate their tanks before any brews. This chemical process will remove any debris gained during transportation and help prevent corrosion. Then, after every batch, they need to use clean-in-place methods. He further mentioned tanks should have fixed or spinning spray balls, and caustic solutions (typically sodium hydroxide) should be used to break down organic matter and liquify material off of the tanks. “Brewing is ninety-five percent 70 WELDING JOURNAL / JUNE 2016 Fig. 6 — While constructing a 9-ft-tall conical bottom for a large fermenter, which is built upside down, Jorge Gamez starts GTAW to join two formed pieces of stainless steel.
Welding Journal | June 2016
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