Solenoid Valves: SAQ Solutions

Listed below are the solutions to the SAQs on Solenoid Valves:

1. An electrically controlled valve that uses a solenoid to control whether a valve is open or closed to fluid flow through it.
   See the video for specifics. These circuit elements are very useful in controlling both gas and liquid flow through medical devices!
2. True.
   A normally open solenoid valve lets fluid through it in a rest position, but seals the valve when energized. A normally closed solenoid valve does the opposite. They can thus be used in different situations depending on whether you want to periodically allow or stop flow.
3. D. Vacuum
   See the video for solenoid valve anatomy. The plunger is used to close the valve, while the coil produces a magnetic field inside the valve and the spring controls valve movement. There is no vacuum in a solenoid valve.
4. Electromagnetic; spring
   The electromagnetic force is produced by the current through the coil. The spring force (see the above question) controls plunger position.