Tech Update<br> Homogenizers deliver high<br> hope for lowering costs
"Total cost of ownership is a key issue," notes Jim LeClair, business unit manager, homogenizers, for APV Products/Invensys, Lake Mills, Wis. "Large players like Dean Foods are driving the homogenizer market by asking ‘What will the real cost of my equipment be over the next five years.' "
LeClair claims this burgeoning of cost-savvy equipment buyers can be seen at both the plant and corporate levels. "Today corporate engineering is dictating what plants can and can't use," says LeClair. "Larger food manufacturing organizations are noticing uptime performance of their equipment and the real expense of operation and ownership. It's a sign of the times and the mandate for lean manufacturing."
"Everyone is looking at overall cost, not just the up-front cost (of equipment)," echoes Ron Tuckner, North American division manager for Niro Soavi, Hudson, Wis. "That means attention to reliability, life of parts, longer equipment life, also production at lower cost."
Save your energyEnergy consumption has been a growing area of concern in food manufacturing. Features that reduce energy consumption have become significant selling points for homogenizers. "Everyone wants to lower energy costs," says Tuckner. "That means the ability to run (pumps) at lower pressures and with smaller motors for greater efficiency."
The homogenization process uses high pressure to reduce particle size in products such as milk, juice and sauces. This high pressure requirement for dispersion, turbulence and acceleration makes correspondingly high energy demands. Hence, manufacturers' endeavors have focused on effecting high-pressure results with low energy output.
Niro's solution has been a high-efficiency valve called the NanoValve. "The flow pattern and design of the NanoValve are different than the standard homogenization valve," explains Tuckner. Particles 0.2 to 20 microns in size within the product are forced through this special homogenizing valve, which operates effectively at low pressure. It reduces particles within a range of 0.4 to 1.0 microns in size.
The Gaulin 185 Q machine from APV/Invensys is a 185 kilowatt machine designed for high volume processing with low energy output. Its 10,000-12,000 gallon per hour capacity requires only 1100-1500 psi, substantially below the usual 2,500 psi requirement of comparable units. The system utilizes APV's Super Micro Gap valve, a set of multiple valves within a single housing. Applicable to non-abrasive dairy products, the valve contributes to high efficiency, low pressure homogenizing - which translates into lower operating costs. Automated control systems and safety devices also help control capacity and pressure.
Make it lastTetra Pak has focused on extending the uptime of its equipment to meet increasingly demanding production schedules of food processing plants.
"Our number one item in our homogenizer is the piston seal," declares Karl Kieffer, production manager homogenizers for Tetra Pak, Vernon Hills, Ill. "Historically, the seal is the number one service item, and the first thing to fail on an homogenizer. The piston seal remains in nearly constant contact with product and is exposed to pressure changes. So we put a lot of attention into lengthening the life of these products, that is, lengthening the time between service."
Tetra Pak's solution is a totally enclosed cylinder. "An enclosed bath ensures that the whole piston is surrounded by liquid," says Kieffer.
Homogenization is a relatively simple concept. Homogenizers differ principally in how they pump and disperse solids.
"An homogenizer is essentially a positive displacement," says Niro Soavi's Tuckner. "That fact hasn't changed. So essentially manufacturers are focused on reliability and efficiency of their equipment." Valves and compression heads have been primary targets of efficiency upgrades. Improved seal, packing and compression head materials contribute today to longer part life.
Demands for efficiency and longer life have put greater attention on maintenance. The result is design tailored to easier access and maintenance.
Expanding usageMore homogenizers are being used to mix and evenly disperse not just fats but a variety of solids including sugars and flavorings. Long associated with the dairy industry, homogenizers are used today in a wide variety of food processing operations including: fruit juices, concentrates, purees, ketchup, tomato products, dressings, liquid eggs, gravies, sauces, mayonnaise, yogurts, yogurt beverages, and ice cream mixes, to name a few.
"An homogenizer is essentially a piston pump that operates at thousands of psi," explains Bill Rice, product manager, pumps and dispersion equipment for Waukesha Cherry-Burrell (SPX Process Equipment), Delavan, Wis. "The pressure is distributed in a pattern that disperses fat globules. We're seeing changes in flow patterns and materials to get better dispersion."
Historically, homogenizers have been workhorses. In fact, some manufacturers tell tales of dairy industry customers who still have equipment initially built in the 1940s.
"Ten year-old machines are considered barely used machines even today," agrees APV's LeClair. "Processors are trying to get as much as they can out of a machine."
Purchasing used or rebuilt equipment is a growing trend in the food industry, he contends. "About 30 to 40 percent of homogenizer buys today are used or rebuilt, especially for higher end equipment."
The pressure is onThe Tetra Alex™ homogenizer series from Tetra Pak's processing division is a recent innovation. The Alex series is designed for high-pressure homogenization of emulsions and suspensions.
Key to the Alex line is a unique homogenization device. Product moves under high pressure into the homogenizing device. There the product is forced through a small annular gap. Pressure pushes product at high velocity. Cavitation and turbulence reduce the size of solid particles, along with liquid droplets.
"We have revamped the design," says Tetra Pak's Kieffer. "The design combines the impact ring and (valve) seat into a single piece, eliminating the higher wear item - the impact ring."
A unique mushroom valve within the high-pressure pump block offers advantages. Its wider dimension enables quick reaction and reduced wear and tear on the machine.
Tetra Alex 400 features a horizontally mounted five-piston positive displacement pump. It can be used in most dairy applications as well as with prepared foods (dressings, ketchup, liquid egg, mayonnaise, sauces and gravies) and fruit juices, concentrates, and tomato products. Other attributes include access to vital parts for service; operation at low noise levels; and the equipment's small footprint. Automation advances enable pressure control from a PLC or even monitoring of operating conditions including oil pressures, temperature, and oil levels.
Stork Food & Dairy Systems, Gainesville, Ga., has also given attention to the homogenizing valve and seat to advance its UHT processors and other equipment. (Homogenizers are not sold separately.) Its valve features pneumatic/hydraulic valve actuation and offers the option of an automatic homogenization control system. The valve and seat are wear-resistant and interchangeable.
With two noted names in the field, Gaulin and Rannie, APV has been integrating the best features of each brand over the past two years. Traditionally, Rannie equipment has been used in high-pressure operations - above 8,000 psi - while Gaulin has been used in lower pressure operations, 10,000 psi and below. "We've taken the best of both brands and put them to best advantage, using top Gaulin valves on Rannie designs and Rannie pumps on Gaulin machines," says LeClair.
APV's Rannie D-175 is used for large volume runs of such products as whipped toppings, peanut butter, and similar prepared foods. The Rannie line is also heavily used today in the processing of soy products.
Homogenization technology has progressed with subtle steps rather than giant leaps. Nevertheless, homogenizers continue to evolve, delivering better efficiency and lower cost with each incremental improvement.
For more information:
Jim LeClair, APV Products (Invensys)
Ron Tuckner, Niro Soavi
Jan Kuiper, Stork Food & Dairy Systems
Karl Kieffer, Tetra Pak Inc. Processing Division
Bill Rice, Waukesha Cherry-Burrell