Control the flow

Valves that are simpler and lower in cost are one reason mid-sized dairy and beverage firms are upgrading to continuous processes (CP) and realizing productivity and economic gains from the implementation of clean-in-process (CIP) techniques. Large and small dairy and non-dairy companies also stand to gain from new valve designs and sealing materials that ensure fail-safe operation for improved hygiene and greater productivity.

“We are starting to see a level of adoption taking place in smaller processing organizations where it is apparent there is a need for continuous processing, either to maximize profitability and efficiency or to stay competitive. The mid-sized organizations are starting to take a serious look at continuous processes,” says Jim Larsen, national manager of business development, valves at Alfa Laval.

More mid-sized dairy companies are buying the technology to become more competitive in terms of capacity through continuous processing. “When a processor looks to expand capacity, the use of mix-proof valves helps it better utilize existing equipment, eliminating the procurement of capital equipment and purchasing of additional production space,” adds Larsen.

Switching to CP? You should know this

Mid-sized dairy plants evaluating a switch to continuous process (CP) should know there is a disadvantage if you do not design your process line for CIP, according to Gabe Miller, senior technical engineer at Sani-Matic, a company that specifies, designs and manufactures sanitation systems that assure process equipment is efficiently cleaned and compliant with regulatory and customer standards. “If you haven’t designed for it and want to add it, you can go back and make changes, and you may be able to clean in a continuous process but not at the most efficient level,” says Miller.

He says to keep in mind that a single CIP system may clean 20 different circuits in a typical plant. “You are trying to minimize cleaning cycle time while ensuring proper flow rate through the valves and piping. So you want to be sure there are no deadlegs in the piping circuit, and there is adequate flow through all segments of the piping circuit,” says Miller.

“During CIP, the system needs to control the process valves, so we are seeing the use of position sensors or control top valves specified more frequently in our system requests,” adds Miller. The CIP control system is integrated with the process control to sequence the timing and duration of valve operation during the cleaning cycle. Miller says it is critical that cleaning control be interlocked with the process to ensure the lines are cleaned with no potential of cross-contamination.

Sani-Matic has developed a new CIP cleaning system that relies on foaming agents rather than recirculating large volumes of cleaning agents and sanitizers. Miller says foaming is less expensive to install—with no return piping—and the cleaning time may be shorter.

The process is creating new business opportunities for Sani-Matic—cleaning vacuum lines used in robotic systems. Miller says many people may not consider the robot handling system as a food safety issue, but the vacuum lines that actuate the robotics that pick up product could possibly pull residues of product into the lines as well. Microbial- and cross-contamination could result as this automation is not commonly designed with cleaning in mind. “The vacuum lines or hoses are easy to clean, but the valves in the robotic systems are often not designed for hot, caustic cleaning. This is where our foaming technology can be more efficient and effective,” states Miller.

Price-competitive valves

SPX offers its WCB W60 and W80 series single-seat valves with a new, lower-cost maintenance-free actuator design and CU4 Control Top, in addition to its maintainable actuator option, says Christopher Sinutko, valves product and aftermarket sales specialist at SPX. The lightweight, compact valve is more economical yet offers the same functionality, seat and seal options, operating limits and body configurations as the standard WCB valves. The actuator unit is available in three sizes to meet various holding pressures for shutoff, divert and throttling applications. It comes with a five-year standard warranty and can be easily reversed in the field to go from air-to-raise to air-to-lower and vice versa.

SPX’ s basic CU4 Control-Top valve features bright LEDs that indicate valve status, manual override solenoids for easy valve actuation and an adjustment screw to throttle airflow to the actuator to prevent hammering. The unit is IP67 washdown rated and can be connected directly to a control system or linked through an AS-i Bus communication.

SPX recently partnered with Burkert, a measurement and control technology supplier, to mount the Type 8681 Control Top onto SPX’s WCB and APV valve brands, says Sinutko. The Burkert design provides advanced, state-of-the art features such as automatic programming of three feedback positions and 360° viewing of the LED status display.

PMO valves for dairy

“Dairy accounts for a large percentage of our business right now, and mix-proof PMO valves play a dominant role, because it means a dairy company can process product simultaneously as it conducts CIP,” says GEA Tuchenhagen President David Medlar. “Mix-proof valves bring continuous processing and productivity benefits into the dairy plant, eliminating the need to shut down the entire line for several hours for cleaning. Mix-proof valve technology allows the dairy processor to operate 24/7 and clean on-the-fly, increasing line flexibility and productivity,” explains Medlar.

A large percentage of major US dairy companies use mix-proof valves as part of their CP and CIP strategy, Medlar adds. The first PMO mix-proof valves—due to PMO regulations in place at the time—were bigger, heavier and costlier, which kept the second tier of mid-sized dairy plants from buying into the technology.

Following a further change in PMO, GEA Tuchenhagen introduced its 24/7 PMO 2.0 valve in 2012. The new valve is smaller, 49 percent lighter, simpler and more cost-competitive than the original 24/7 PMO valve launched in 2007. The fail-safe design eliminates any chance of cleaning fluid contaminating the product, even if the seat seals are in the valve, out or damaged. GEA reports up to a 45 percent reduction in CIP losses during cleaning with the valve, greatly reducing water and chemical costs.

The valve design generates a natural vacuum in the vent cavity during seat lift, without the use of any additional complex parts or deflector plates. Featuring no gaps or deadlegs, the open, unrestricted cavity area eases cleaning, even for more viscous products such as yogurt. All the valve seats are position detectable and monitored with GEA’s T.VIS automated control modules. “Control of a mix-proof valve is critical because you are handling product and cleaning liquids simultaneously within the valve system, so proper monitoring of the valve seat positions is required,” according to Medlar.

The new T.VIS A-8 valve is a self-calibrating module that replaces discrete proximity switches. Once the valve is installed in the pipework, pressing buttons atop the control module sends the unit through a series of automated functions, defining all its conditions and getting the valve set up, ready for control, fully protected and monitored in 30 seconds.

GEA Tuchenhagen recently purchased Aseptomag, a Switzerland-based manufacturer of single-seat and mix-proof aseptic valves. Medlar says the cost-competitive Vesta series of compact, hermetically sealed, PTFE bellows, single-seat aseptic valves from GEA will fall under the Aseptomag brand going forward.

Earlier this year, SPX introduced the W75CP2 valve, the second generation of its W75 series of PMO-compliant, double-seat mix-proof valves for dairy and CIP operations. The new, more compact model takes advantage of the revision to the Pasteurization Milk Ordinance (PMO). It also meets the latest 3-A Sanitary Standard 85-02 which allows the atmospheric vent to be smaller than the largest pipeline diameter, as long as no impingement of cleaning liquid on the opposite seat gasket occurs during seat lift, and the pressure in the critical seat area of the valve vent cavity remains atmospheric at all times, says Sinutko.

The new valve uses an actuator that is up to 50 percent smaller than previous designs, and reduces air consumption by up to 70 percent. The W75CP2 model is up to 36 percent lighter in weight for easier handling and maintenance. However, the port-to-port centerline dimensions are the same as the first design iteration to allow customers to easily add onto existing W75 series valve manifolds, states Sinutko. Model extensions for tank outlet and tank outlet curd are also available.

Thinking tank

This year, Alfa Laval launched the Unique PMO Plus-CP tank valve with onboard cleaning devices that enable cleaning the valve and tank outlet without flooding the tank to clean the port, reducing water usage and cleaning time. The continuous process tank valve is designed for vertical and horizontal tank outlet applications and allows cleaning of the vessel separate from the supply or discharge pipelines, a move said to maximize the utilization of vessels and asset uptime.

The tank valve is designed for gentle handling and the passing of particles such as curd or fruit up to 1.75 in. in diameter. The design also enables high-speed discharging of vessels under gravity while maintaining mix-proof conditions right up to the tank wall.

GEA’s new 24/7 PMO-type MT tank valve is completely drainable in the horizontal and upside-down positions for floor space savings. The unit can be mounted directly to the vessel, simplifying pipework. The lower pressure drop of the system, compared to standard PMO valves, is ideal for large particulate and viscous products, such as up to 1.75-in. size cheese curd, without product shearing. The valve’s close-coupled CIP return line minimizes product deadleg that can be associated with a block-and-bleed system.

New seat material for mix-proof valves

Alfa Laval’s Unique mix-proof valve utilizes elastomeric seals for the upper primary seal, lower primary seal and lower plug shaft seal to create the double block-and-bleed function. Having fewer sealing points increases the hygiene of the valve by reducing the probability of leaks. The valve also has fewer maintenance points and fewer maintenance turns, according to Larsen.

Since a pressure gradient from the product side of a particular seal to the atmosphere always exists, the valve never gets transition from the atmosphere into the product zone. The valve can be cleaned through a seat lift under gravity alone, so it does not have to operate with a pump or pressurized CIP system, explains Larsen.

SPX added a PEEK engineering elastomeric material as a seat option for its Waukesha Cherry-Burrell (WCB) W71 shutoff and tank outlet series as well as its W73 divert series of mix-proof valves. PEEK seats are designed for critical applications where typical elastomers will not suffice, says Sinutko. The two seat ring inserts located on the upper and lower stems create a seal between the stems and body to separate fluids when the valve is in the closed position and shut off the atmospheric vent cavity when the valve is open. The non-porous, chemically inert PEEK material provides high corrosion resistance, unaffected product taste and non-sticking seats in a long-lasting compression seal design that withstands temperatures up to 280°F.

Other developments

SPX’s first line of electro-pneumatic positioners that sit atop the WCB brand W68 series valves deliver the accurate, stable control of flow or pressure. The positioners, supplied by Burkert, require a 4-20 mA electrical signal that connects directly to the unit for “plug & play” installation and instantaneous analog feedback of the valve position. No external I/P convertor is necessary. The auto-tune calibration also provides an easy setup.

The electro-pneumatic positioner features fewer moving parts and springs compared to competing designs and is a contactless, wear-free position measuring system, says Sinutko. It eliminates continuous leaking or hissing of compressed air, greatly reducing air and energy costs in a plant. Designed for use in many throttling applications including fillers, backpressure, separators, utilities, reverse osmosis and membrane filtration, the positioner can be controlled through direct wire, AS-i Bus or DeviceNet communications.

Alfa Laval offers the Unique 7000 vacuum breaker valve to eliminate vacuum on the downstream side of any pasteurization system. During CIP, a pneumatic actuator is used to move the ball-type check valve off the upper seat, allowing cleaning of the seat and internal vacuum breaker surfaces.

When the pipelines are pressurized during process conditions or CIP, an internal ball is forced upward against the valve’s seat, closing the vent port. When pipeline pressure drops, the ball is drawn down, allowing air to enter the vent, preventing unwanted vacuum in the process system. The FDA- and 3A-compliant breaker valve can be fitted with an IndiTop or ThinkTop position indication unit that verifies valve function performance during operations, says Larsen.