Basic types
Solenoid valves are opened and closed via a solenoid that is activated by an electrical signal. In most industrial applications, solenoid valves are of the following five types.

(1) Two-way solenoid valves
This type of solenoid valve normally has one inlet and one outlet, and is used to permit and shut off fluid flow. The two types of operations for this type are “normally closed” and “normally open”.

(2) Three-way solenoid valves
These valves normally have three pipe connections and two orifices. When one orifice is open, the other is closed and vice versa. They are commonly used to alternately apply pressure to an exhaust pressure from a valve actuator or a single-acting cylinder. These valves can be normally closed, normally open, or universal.

(3) Four-way solenoid valves
These valves have four or five pipe connections, commonly called ports. One is a pressure inlet port, and two others are cylinder ports providing pressure to the double-acting cylinder or actuator, and one or two outlets exhaust pressure from the cylinders. They have three types of construction; single solenoid, dual solenoid, or single air operator.

(4) Direct-mount solenoid valves
These are two-way, three-way, and four-way solenoid valves that are designed for gang mounting into different quantities of valves. Any combination of normally closed, normally open, or universal valves may be grouped together. These series are standard solenoid valves whose pipe connections and mounting configurations have been replaced by a mounting configuration that allows each valve to be mounted directly to an actuator without the use of hard piping or tubing.

(5) Manifold valves
A manifold of solenoid valves consists of a matrix of solenoid valves mounted in modules on a skid with adjustable legs along one direction. The number of valves depends on the elements to be connected and on the functions of each of these elements. A plurality of solenoid valves is arranged and placed on the installation face of the manifold, and a board formed with an electric circuit for feeding these solenoid valves. Each solenoid valve includes a valve portion containing a valve member and a solenoid operating portion for driving the valve member. The board is mounted on the first side face of the manifold under the solenoid operating portion. The board can be attached and detached while leaving the solenoid valves mounted on the manifold, feeding connectors and indicating lights being provided in positions on the board corresponding to the respective solenoid valves. Each feeding connector is disposed in such a position that it is connected to a receiving terminal of the solenoid valve in a plug-in manner when mounting the solenoid valve on the manifold. Each indicating light is disposed in such a position that it can be visually recognized from above the solenoid valve while leaving the solenoid valve mounted on the manifold.

This manifold allows the centralizing of the functions of one or various tanks in a modular way, enhancing the efficiency of the system and the degree of control over the process. The solenoid valve manifold is an automated alternative to flexible hoses and flow divert panels with changeover bends. As many valves as the number of functions the element has to perform are connected to the tank or working line. No manual operation is required. The operation is automated, preventing any risk of accidents.