Two-way solenoid valves are divided into double solenoid valves and single solenoid valves. The easiest way to tell the difference is to look at the number of coils.
Single solenoid valves have only one solenoid coil; double solenoid valves have two solenoid coils.
Single electric control solenoid valve: that is, there is only one solenoid coil. Based on practical application considerations, if the valve reversal time is not long, it is recommended to choose a single control solenoid valve, just like a single-acting cylinder, with spring return, and when the coil is charged, it is Excitation), push-off (spring return) working mode when power is lost. Generally, single control is used in 2-position 3-way solenoid valves, and the coil voltage level generally adopts DC24V, AC220V, etc. The two-position three-way solenoid valve is divided into two types: normally closed type and normally open type. The normally closed type means that the air path is open when the coil is not energized, and the normally open type means that the air path is open when the coil is not energized. The operating principle of the normally closed two-position three-way solenoid valve: energize the coil and connect the air path. Once the coil is deenergized, the air path will be disconnected, which is equivalent to "jogging". The operating principle of the normally open two-position three-way single solenoid valve: energize the coil and the air circuit is disconnected. Once the coil is deenergized, the air circuit will be connected, which is also a "jogging".
Double electric control solenoid valve: It has two solenoid coils, just like a double-acting cylinder, without spring return. The two coils can only have one excitation, working in a push-and-pull manner. Generally, dual control is used in a two-position five-way solenoid valve. The operating principle of a two-position five-way double electric control solenoid valve is: energizing the forward action coil, the forward action air path is connected (there is air in the forward action air outlet), even if the forward action is energized After the coil is powered off, the forward action air circuit is still connected and will remain open until the reverse action coil is powered on. When the reaction coil is energized, the reaction air circuit is connected (there is air in the reaction outlet). Even after the reaction coil is powered off, the reaction gas circuit is still connected, and it will remain connected until the forward action coil is energized. . This is equivalent to "self-locking". Based on the characteristics of the two-position five-way double electric control solenoid valve, when designing the electromechanical control circuit or programming the PLC, the solenoid valve coil can be operated for 1 to 2 seconds, which can protect the solenoid valve coil from being easily damaged.