A 2/2-way solenoid valve is a type of valve that has two ports and two states: open and closed. These valves are commonly used to control the flow of liquids and gases in a variety of applications, including water treatment, HVAC systems, industrial automation, and medical equipment.

In a 2/2-way solenoid valve, a solenoid is used to control the position of a plunger or diaphragm inside the valve. When the solenoid is energized, the plunger or diaphragm is moved, allowing fluid to flow through the valve. When the solenoid is de-energized, the plunger or diaphragm returns to its original position, closing the valve and stopping the flow of fluid.

The "2/2" in the name refers to the number of ports and the number of states of the valve. The first "2" indicates that the valve has two ports, an inlet and an outlet, while the second "2" indicates that the valve has two states, open and closed.

For example, 

The Parker 7321 series solenoid valve is a family of two-way, normally closed solenoid valves designed for use in a variety of industrial applications. These valves are available in a range of sizes and materials to suit different fluid handling needs.

The valves in the 7321 series feature a reliable solenoid design that ensures consistent performance over time. They are available in both AC and DC voltages and have up to 20 bar operating pressure, making them suitable for use in a wide range of electrical systems.

The body of the 7321 series solenoid valve is typically made of brass, stainless steel, or other materials that are resistant to corrosion and wear. The valve seats are made of a variety of materials, including PTFE, Viton, and EPDM, to ensure compatibility with different fluids.

The Parker 7321 series solenoid valve is typically used in applications such as air compressors, water treatment systems, and other fluid handling systems. These valves are known for their reliability, durability, and ease of installation, making them a popular choice for many industrial settings.

Overall, the Parker 7321 series solenoid valve is a high-quality valve that provides reliable performance and long service life in a wide range of industrial applications.