When current is sent to the coil, it creates an electromagnetic field that forces the plunger downwards overcoming the spring force. Figure 3 shows an example of a 2-way solenoid valve.įigure 6: Operating principle of normally open solenoid valve: de-energized (left) & energized (right)įor a normally open solenoid valve, the valve is open when de-energized and the media can flow through it. A 2-way valve is used to open or close the orifice. Flow direction is critical to ensure proper operation, so there is typically an arrow indicating the flow direction. 2-way solenoid valveĪ 2-way solenoid valve has two ports, an inlet and an outlet. For an in-depth understanding of symbols and understanding circuit function diagrams, view our valve symbol page. An overview of 2-way and 3-way solenoid valves is below. The specific purpose of a solenoid valve is expressed by its circuit function. Solenoid valves are used to close, open, dose, distribute or mix the flow of gas or liquid in a pipe. The three most important ones are explained in this article: direct acting, indirect acting, and semi-direct acting operation. These solenoid valves use different operating principles that are optimal for the application. Solenoid valves are used in a wide range of applications, with high or low pressures and small or large flow rates. The shading ring (C) prevents vibration and humming in AC coils. If the valve is normally open, the plunger moves downward so that the seal (F) blocks the orifice and stops the flow of the media through the valve. If the valve is normally closed, the plunger is lifted so that the seal (F) opens the orifice and allows the flow of the media through the valve. This creates a magnetic attraction with the plunger, moving it and overcoming the spring (D) force. When current flows through the solenoid, the coil is energized and creates a magnetic field. In the de-energized state, a normally open valve is open and a normally closed valve is closed. At rest, it can be normally open (NO) or normally closed (NC). A solenoid has an electromagnetically inductive coil (A) around an iron core at the center called the plunger (E). Figure 2: Components of a solenoid valve coil (A) armature (B) shading ring (C) spring (D) plunger (E) seal (F) valve body (G)Ī solenoid valve consists of two main components: a solenoid and a valve body (G).

Electric solenoid valve water