Nestlé USA, part of Nestlé S.A., a world leader in infant nutrition, manufactures Nestlé Good Start Supreme DHA & ARA. The new formula contains two fatty acids, docosahexaenoic acid and arachidonic acid, also known as DHA and ARA, which are naturally found in breast milk and have been linked with improved brain and visual development in babies.
Nestlé USA’s, manufacturing plant in Eau Claire, WI uses a tall form spray dryer for the production of its infant formula. On the four outlet cyclones where the powder is recovered from the hot gas stream, Nestlé was using flap-gate airlock valves. These basic valves provided a very poor seal so vacuum was hard to maintain. The airlock was also difficult to clean and maintain. Metal on metal contact points of the flap gate was also a concern in this high purity environment.
Larry Willi, Facilities Engineer at Nestlé was given the goal to upgrade the airlocks. His objectives were to reduce downtime, improve the quality and increase productivity of the process. He brought his team together to consider the options. One option was a rotary valve, but the maintenance department had bad experiences with them. In their opinion, the rotary valve requires too much time in cleaning and maintenance.
For Nestlé this was a fast track engineering project. Most of the specifications existed it was a matter of it fitting into an area. “We knew what we wanted and had to find a company that would meet our goals and specifications” Mr. Willi said.
On one side of the valve was 3″ of vacuum on the other atmospheric pressure. This process required an airlock. Core temperature of the product is 160° F, and the room temp is 120° F, typical of most spray drying applications. The valves had a requirement, besides temperature and vacuum, to cycle 4,500 times per day to keep the process flowing, and to be designed for 1,000,000 cycles between service intervals.
Another challenge was a size requirment as neither the upstream or downstream process equipment could be moved without undergoing considerable expense. This meant the airlock had to conform to a specific space between these components.
After exhaustive research into valve and airlock solutions, Mr. Willi finally found Gemco Valve on the Internet and called in Jim Lenihan, Gemco Valve’s President to provide a solution.
Mr. Lenihan demonstrated Gemco Valve’s new K Valve to Nestlé’s engineering and process teams. The sanitary K Valve is designed to USDA and FDA guidelines eliminating threads, keyways, and crevices. The split body design means the K-valve can also be completely disassembled with simple hand tools allowing quick and easy inspection and cleaning. It is used for charging/discharging or in-line with standard quick clamps allowing fast installation and removal. The K valve is offered in sizes from 3″ to 10″ (75 to 250mm) in practically any weldable alloy, with the option of #4 satin or #7 mirror finish. Pressure and vacuum applications are engineered to order. Commonly used in the food, pharmaceutical and nutraceutical industries or anywhere where cleanability and quick change over is required.
“Most vendors tried to sell us something off the shelf but nothing suited the application. Gemco Valve was prepared to engineer their standard valve to fit our application,” remarked Mr. Willi.
After a few minutes of the engineers studying the K-valve, they said “Wow this will work.” The Nestlé engineers easily conceptualized the process during the meeting. One K-valve will be orientated in the up position, the other K-valve down with a chamber in the middle for the pressure differential. Air logic was incorporated to automate the process of cycling the K-valve Airlock. Gemco Valve and Nestlé engineers worked together using electronic drawings that reduce the engineering and drawing approval cycle time so a tight schedule could be maintained.
Meanwhile, Mr. Willi was engineering a system for cleaning and maintenance. As the K-valve Airlock weighed 300 lbs, Mr. Willi developed a track system to slide the K-valve Airlock in and out of service for each of the four cyclones. The Airlocks are cradled between two tracks approximately 8 feet in length and the cradle was mounted on wheels. This system allows maintenance to easily slide the units in and out of the process.
Gemco Valve had provided a mounting bracket that acted as a swivel point in the center of the airlock chamber to allow Nestlé maintenance personnel to rotate the Airlock 90° making it easier to perform inspection and cleaning. Also, the wheels were fitted with springs to allow for the temperature expansion and contraction of the cyclone, which enable Nestlé to maintain the required seal.
The four Gemco K-Valve Airlocks were put in service on 1 August 2004 and have been operating continuously since. “Our goal is two times a year cleaning and servicing of the K-valve Airlocks in this application. So far we are on target for the 6-month service point and this was one of the easiest startups I’ve been through” said Mr. Willi.
