PMO approves electronic low-emission flip-flop function for GEA double-seat valves used in dairy processing

Dairies in the USA can now save up to 90 percent on CIP media, thanks to the special LEFF® (Low Emission Flip Flop) water-economizing function from GEA. GEA has been granted approval under the US Pasteurized Milk Ordinance (PMO) for this control function for double-seat valves. Double-seat valves from the 24/7 PMO 2.0 Valve® range are deployed in non-aseptic dairy processes where milk is drawn off, stored, distributed and filled. 

Shear forces optimally exploited

Sealing zones on the valves can be cleaned separately by LEFF® with their sealing function entirely retained. This means that they can work around the clock, regardless of process run-times and product pressures, without interrupting production for CIP. “The principle is based on a flip-flop movement of the valve disks,” explains Bernd Porath, product manager for hygienic valve technology at GEA. “At the moment when the disk lifts from the seat and opens up a cleaning gap, the cleaning medium flows in. That’s when shear forces are at their greatest, and they clean most effectively. We leverage this principle, and the closing and opening of the valve disks, in a very specific manner.”

Microchip in the valve head saves 90 percent of cleaning media

LEFF® is integrated as standard in the T.VIS A-15 control head of the 24/7 PMO 2.0 Valve®. Path-controlled electronics, for which GEA already holds a patent, pulse-controls the moment and degree of opening of the valve disk with absolute precision. Bernd Porath again: “The microprocessor responsible for the control function is located directly in the valve head, and not in the PLC as is customary. This means we can shorten the data paths and speed up the flip-flop movement by valuable milliseconds.” Thanks to the path measuring system, GEA is able to improve the economizing effect even further in comparison with elaborate and expensive PLC programming. The faster a valve disk opens and closes, the less cleaning medium runs through, with optimal cleaning performance. “Our customers want their production to be optimized when it comes to operating costs, while remaining constant and consistent. They are saving up to 90 percent on CIP media, including expensive cleaning agents as well as water and wastewater.”

Cleaning in continuous operation

Flip-flop control in GEA valve heads saves 90 percent of cleaning media
CIP losses in the course of time: The LEFF® function can simply be switched on at the T.VIS A-15 control head. The activation for double disks requires an external proximity initiator. (Graphic: GEA)

While low emission flip-flop has already become standard in Europe for a number of major milk-processing operations, to date, the function had not been approved in the control head of the double-seat valve in the USA. In order to totally exclude the risk of contamination, the US PMO regulation had not permitted the product and the cleaning fluids to run through a valve at the same time. As a result, cleaning cycles have incurred considerable, cost intensive downtimes for producers. 

GEA engineers have now rearranged double-seat valves for milk processing in line with the PMO specifications, and eliminated the risk with a special underpressure in the leakage space suctioning up any cleaning medium that may have overflowed, thus pressure cannot build up on the valve disk. This means that if a line and its sealing points are being cleaned, the other line can still continue to conduct product. Now dairies will no longer have to interrupt operations to carry out CIP cleaning, because the offset cleaning of the GEA 24/7 PMO 2.0 Valve® double-seat valves prevents any mixing of CIP and product, with total reliability. 

Approval under PMO for dairy applications in the USA

GEA is the first manufacturer of double-seat valves able to meet the strict requirements of the PMO. “This is a breakthrough in the US where water shortage is a critical issue, especially in California. We are particularly pleased that we are now able to help our customers in the USA with LEFF® by lowering water consumption and alleviating other cost pressures in their operations,” is how Bastian Tolle, head of product group management Flow Components at GEA, sums up the situation.

Good news for existing customers in the United States: LEFF® is already integrated in the T.VIS A-15 control head of the GEA 24/7 PMO 2.0 Valve®, and only needs to be switched on to be used in existing applications. There is no need for any additional system technology or programming.

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