The difference between the normally open and normally closed solenoid valves

The solenoid valve mainly uses electric power as an energy source, and the electric current generates electromagnetic force by driving the electromagnetic coil, and then the electromagnetic force controls the valve by controlling the spring. Of course, this spring can be used both to control the closing of the valve and to control the opening of the valve. Therefore, according to this characteristic, we can make the gas circuit break when the coil is not energized. This is the normally closed type valve, and the gas circuit can be made when the coil is not energized. This is the normally open type valve.
    The working principle of the normally closed solenoid valve is: the coil is energized, the gas path is turned on, and once the coil is de-energized, the gas path is disconnected, which is equivalent to "jog". The working principle of the normally open solenoid valve is to energize the coil, the gas circuit is disconnected, and once the coil is de-energized, the gas path will be connected, which is also "jog".
    Usually chosen according to the length of continuous working hours: normally closed, normally open, or continuously energized
    1. When the solenoid valve needs to be opened for a long time, and the duration of the excess closing time should be the normally open type.
    2. If the opening time is short or the opening and closing time is not much, then the normally closed type is selected.
    3. However, some working conditions for safety protection, such as furnace and kiln flame monitoring, cannot be selected for normal opening.