Hand operated 3/2 DCV
The cross sectional views of 3/2 DCV (normally closed) based on spool design is shown below.
When the valve is not actuated, port 2 and 3 are connected and port 1 is blocked. When the valve is actuated then port 2 and 1 are connected and port 3 is blocked.
Figure shows schematic diagram of 3/2 spring operated valve. There are three ports common port, normally open port and normally closed.
When the valve is not actuated, there is flow from NO port to common port. When the valve is actuated there is flow from NC to common port.