The Lock out, Tag out device (LoTo principle for valve technology) is used to ensure a safe maintenance and commissioning of process plants. Energy sources will be locked and visually marked to prevent the unintentional movement of the valve. These mechanical or pneumatic locks help plant operators effectively protect their workforce from hazards in production.

A GEA LoTo unit comprises a shut-off device that fixes the valve in the open or closed position and an optional lock that only authorized individuals can open. The type of fixing varies depending on the type of valve; they are available for all nominal diameters and actuator sizes and can easily be retrofitted:

• Butterfly valves can be shut off mechanically. The disk lock version uses a pin that is pushed into the valve stem and can also be used with an extension. This principle can similarly be applied to leakage butterfly valves.
• There are two ways of shutting off single-seat valves: Either the air supply can be shut off directly on the control top or actuator using the air lock principle, or the entire actuator can be locked via a disk lock which prevents the valve disks from moving. This is advisable where a higher level of safety is desired. In the event of a water hammer, the valve remains closed, ensuring an almost completely leak-proof system.
• GEA offers a bellow lock for VESTA® valves in aseptic applications with manual actuators which is suitable for large and small nominal sizes.
• GEA LoTo solutions are generally designed for single-seat valves, but the main stroke in double-seat valves can also be locked. As VARIVENT® and D-Tec® valves with lift can still be actuated, the operator should consider using further safeguards here - for example, air supply to the lifts.