Multi-path control valves type Z1B-M

The suitability of valves for operation in high pressure drop conditions depends on the design of the valve’s internal components.
The parameter determining the permissible critical pressure drops under throttled or cavitation flow conditions is the pressure recovery factor FL.
∆p = K∙FL2(p1-pv)
K=0.85 – for throttled flow
K=0.67 – for cavitation
The value of the pressure recovery factor FL may vary between 0.5…1.0 depending on the type of valve. High pressure recovery valves (butterfly valves, ball valves) have a low FL value and are not suitable for operation under throttled flow and cavitation conditions.
For these applications, the design of the valve should ensure that the maximum FL values are achieved.
These requirements are met by Z1B-M valves with labyrinth multipath flow direction of the stream in the valve throttling elements (FL=fi0.975).