Block-and-Bleed Solutions – GEMÜ Multi-port Valves

In the pharmaceutical, food, and biotechnology industries, GEMÜ multi-port valves are essential for integrating diverse process requirements and functions within compact spaces. GEMÜ’s block-and-bleed solutions significantly enhance process reliability and safety during maintenance and calibration, as well as prevent cross-contamination by reducing dead-legs. Depending on the application, various configurations are available for shutting off (block) and draining or venting (bleed), with each differing in construction. This eliminates the need for complex piping systems. With minimal welds, not only are leak paths reduced, but weight and installation time are also significantly decreased.

The different design versions of the block-and-bleed functions can be categorized into the following groups:

1.       Simple block-and-bleed valves

In the simplest form, block-and-bleed valves have two valve seats and are used to safely remove in-line measurement devices for maintenance or calibration. An additional valve provides necessary pressure compensation and is positioned separately in the piping.

2.       Double block-and-bleed valves

Double block-and-bleed valves with three integrated seats are used for critical processes, ensuring reliable separation of media. This setup creates a redundant barrier between incompatible media. This method of double shut-off is also described as a measure to avoid cross contamination of product streams and potential risks to personnel working downstream.

3.       'Sterile cross' valves (steam barrier)

Compared to double block-and-bleed valves, multi-port valve blocks used as a “sterile cross” have an additional valve seat and connection, totalling four seats and connections. This design creates a permanent moisture barrier between the closed seats, preventing media contamination.

4.       Complex block-and-bleed valves

Multi-port valves can be customized to meet specific process requirements, with the design and number of connections and valve seats varying based on the media to be combined. For example, “crossover cleaning” uses two double block-and-bleed functions to prevent product contamination during CIP cleaning. This can be achieved with three separate multi-port valves or a complex multi-port valve block.

For more in depth information on the block-and-bleed function groups, please see on below page 10:

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