what benefit does a control valve with no 'shut-off' provide?

In the rare case that the selected control valve has insufficient Cv for the application, customers may opt for a trim design with significantly larger open area (such as our ‘B1’ trim geometry). This will provide an increase in flow capacity, however when fully ‘closed’, the valve will not provide shut-off capability. This is typically acceptable to customers who also have an isolation valve (upstream or downstream), or do not require shut-off at the control valve.