BY FUNCTION
Isolation / Shut-off Valves
What the valve is asked to do in the line — isolation, non-return, regulation, protection or diversion.
Choosing Isolation / Shut-off Valves
Isolation duty requires a defined closed boundary and an acceptable full-open pressure loss. Gate, ball, globe and butterfly designs offer different passage, seating and maintenance arrangements. Begin with the isolation purpose, fluid and closing differential before choosing a family.
What to include in the RFQ
- Define the maintenance boundary and the permitted seat leakage under the specified test.
- State maximum closing differential, operating frequency and manual or remote operation.
- Identify material, connection, access and any trapped-fluid pressure concern.
Selection scenario
For pump maintenance, identify which upstream and downstream boundaries must be isolated and how pressure is verified before work. Use that system description to compare valve assemblies.
Common selection mismatch
A non-return device or a regulating position does not by itself establish the required maintenance-isolation arrangement.