What are the principles and characteristics of direct-acting solenoid valves?

Normally closed type is closed when the power is off. When the coil is energized, electromagnetic force is generated, which makes the moving iron core overcome the spring force and attract the static iron core to directly open the valve. The medium is a path; there are two types: normally closed and normally open. When the coil is de-energized, the electromagnetic force disappears, the moving iron core is reset under the action of the spring force, and the valve port is directly closed, and the medium is blocked. Simple structure, reliable action, and works normally under zero pressure difference and micro vacuum The normally open type is just the opposite. Such as the solenoid valve with a flow diameter of less than φ6.

Principle: When the normally closed type is energized, the electromagnetic coil generates electromagnetic force to lift the open piece from the valve seat, and the valve opens; when the power is off, the electromagnetic force disappears, and the spring presses the open piece on the valve seat, and the valve opens. (Normally open type is relatively opposite)

Features: It can work normally under vacuum, negative pressure and zero pressure, but the diameter is generally not more than 25mm.