Table of Contents

What is Direction Control Valve | Types Of DCV in Fluid System

What are Directional Control Valves ?

As the name suggests, the function of a directional control valve (DCV) is to control the direction of flow in a hydraulic circuit. ;
In other words, directional control valves (DCFs) regulate the direction in which the I fluidflows in a hydraulic circuit. ;
In addition to controlling direction of actuator motion, the directional valves are also used to select alternate control circuits, and (zr) to perform logic control functions.
These valves are not intended to change the rate of flow of fluid; but they are either completely open or completely closed. They can be actuated to switch the fluid flow direction by various actuating means such as electrical, mechanical or fluid pressure signals. This results in corresponding connection or disruption of flow between various port openings.

Classification of Directional Control Valves

The directional control valves can be classified in many different ways.

1. The directional control valves are basically classified, according to the construction into three groups, as

1. Poppet (or seat) valves,
2. Sliding spool valves, and
3. Rotary spool valves.

2. Based on the number of ports’ present, the directional control valves may be classified as

(1) Two way valves,
(2) Three way valves, and
(3) Four way valves. .

3. Based on the mode of actuation, the directional control valves can be classified as :

(1) Manually operated directional valves,
(2) Mechanically operated directional valves,
(3) Solenoid operated directional valves, and
(4) Pilot operated directional valves. .

4. However, for our study we can classify the directional control valves into three :
1. Check valves,
2. Position valves, and
3. Shuttle valves.

Specification

Diectional Control Valves are generally specified using the number of ports and the number of switching positions. It can be represented in general form as np/ns, where np is the number of ports connected to the direction control valve and ns the number of switching positions.

In addition, the method of actuation and the return method can also be specified. A hypothetical valve could be specified as 4-way, 3-position direction control valve or 4/3 DCV since there are four ports and three switching positions for the valve. In this example, one port is called the pressure port which is connected to the pump; one port is the tank port and is connected to the tank (or reservoir); and the two remaining ports are called working ports and are connected to the actuator. Apart from characteristics of valve the fluid suitable for valve, working temperature and viscosity also thought upon before selecting a particular type of valve.