What Is the Working Principle of a One-Way Solenoid Valve?

A single-cylinder one-way solenoid valve, a pneumatic manipulator used for transporting materials, a double-cylinder one-way solenoid valve, and two one-way solenoid valves. From the diagram below, we can see that the solenoid directional valve is a whole, and the air inlet and air outlet of each directional valve are connected, which we call a valve. When air is supplied, only one air guide tube is needed.

The coil of a solenoid directional valve has two wires: one is a red wire, connected to the positive terminal of a 24V DC power supply, and the other is a blue wire, connected to the negative terminal of the DC power supply. The red indicator light inside the one-way solenoid valve has polarity; if the wires are connected in reverse, the indicator light of the one-way solenoid valve will not light up, but it can still make the one-way solenoid valve operate. In a real control circuit, the one-way solenoid valve can be controlled by various relays, and it can also be controlled by the output terminals of a PLC. When I taught students to install the seven sets of one-way solenoid valves used in the material sorting organization, their coils were controlled by a programmable logic controller (PLC).

One-way solenoid valves can be divided into single one-way solenoid valves and double one-way solenoid valves. The high-temperature normally open solenoid valve is used to control the movement of a cylinder in a single direction, enabling the cylinder's extension and retraction; a double one-way solenoid valve can control the air intake and exhaust of the cylinder, thereby achieving the cylinder's extension and retraction. On the sorting organization production line, the one-way solenoid valves used by the pneumatic manipulator are double, while the one-way solenoid valves used to sort materials on the material conveyor belt are single.

The difference between a single one-way solenoid valve and a double one-way solenoid valve is that the original position of the single one-way solenoid valve is arbitrary, and it can control 2 positions at will. The original position of the single one-way solenoid valve is fixed, and it can only control one direction.

Working principle of the one-way solenoid valve:

Let's use the clamping and releasing of a pneumatic gripper to explain the working process of a one-way solenoid valve. Taking the control of a single piston-type normally open solenoid valve as an example: when the drive coil of the one-way solenoid valve is energized, its internal normally open contact closes, allowing the 24V voltage to energize the control valve; at this time, the valve changes from closed to open, and the high-pressure air from the air source enters the pneumatic gripper through the air pipe, making the gripper clamp; when the one-way solenoid valve is de-energized, the internal one-way solenoid valve automatically retracts under the action of the spring, and the gripper automatically opens. In this way, the one-way solenoid valve uses the energizing and de-energizing of the internal magnet coil to open and close the pneumatic pipe, so it has two pneumatic pipelines: one is the air inlet path and the other is the air outlet path, as shown in the figure.

When the gripper is controlled by a double one-way solenoid valve, the clamping of the gripper uses one one-way solenoid valve, and the releasing of the gripper uses another one-way solenoid valve; at this time, they need 2 sets of four air pipes to complete the air intake and exhaust. When controlling a double one-way solenoid valve, the two one-way solenoid valves must not be energized at the same time.

The products supplied by one-way solenoid valves are very widely used in hydraulic control and pneumatic control. For example, a large number of one-way solenoid valves are used in automated assembly lines and hydraulic control circuits; they can not only control the inflow and outflow of gas but also control the inflow and outflow of liquid. When gas is used as the transmission medium, a compressor source is needed to supply high-pressure gas, such as an air compressor.