Hydraulic valves are the brain of the system. They control the
direction, pressure, and flow rate of the fluid, ensuring the machine operates as
desired. In this guide, we examine in detail the valve types used in industrial
applications, their working principles, and selection criteria.
Basic Knowledge
Hydraulic valves are divided into three main
categories:
Directional Control Valves, Pressure Control
Valves,
and
Flow Control Valves. Each category offers solutions for different
system needs.
1. Directional Control Valves
Directional control valves determine where the hydraulic fluid goes in the system.
Basic functions such as the forward-backward movement of the cylinder and the direction
of rotation of the motor are provided by these valves.
1.1. Valve Definitions
Valves are defined in the format number of ports/number of positions.
For example,
4/3 valve: Means 4 ports (P, T, A, B) and 3 positions.
| Valve Type |
Positions |
Typical Application |
| 2/2 Valve
|
Open/Closed
|
Simple ON/OFF
control |
| 3/2 Valve
|
3 ports, 2
positions |
Single acting
cylinders |
| 4/2 Valve
|
4 ports, 2
positions |
Double acting
cylinder, continuous |
| 4/3 Valve |
4 ports, 3 positions |
Double acting cylinder, center position |
1.2. Actuation Types
- Solenoid
(Electric): Ideal for automation systems, fast response
- Manual
(Lever/Pedal): Applications requiring operator control
- Pilot
Operated: For high flow systems
- Proportional:
Precision position and speed control
"The valve is the brain of the system. Providing precise control with proportional
and servo valves is the cornerstone of modern hydraulics."
— BRS PROSES Engineering Team
2. Pressure Control Valves
Pressure control valves limit, regulate, or redirect pressure in the system.
They are critically important for safety and performance.
2.1. Main Pressure Valves
- Relief Valve: Limits maximum system
pressure, discharges to tank line in case of overpressure
- Pressure Reducing Valve: Provides lower
pressure
in a specific line
- Sequence Valve: Activates the secondary circuit
when a certain pressure is reached
- Counterbalance
Valve:
Provides control in cylinders pulled by the load
Critical Warning
A hydraulic system without a relief valve
must never be operated. Excessive pressure can lead to hose bursts,
seal damage, and serious injuries.
3. Flow Control Valves
Flow control valves adjust the speed of the fluid (flow rate). They are used for
cylinder
speed and motor speed control.
3.1. Flow Control Types
- Throttle Valve:
Simple flow restriction, pressure dependent
- Flow Control
Valve: Pressure-independent constant flow
- Flow Divider:
Distributes flow equally or proportionately
4. Advanced Valve Technologies
4.1. Proportional Valves
Proportional valves adjust position or pressure proportionally with an electrical
signal.
They work integrated with PLC control to provide precise automation.
4.2. Servo Valves
Servo valves are designed for applications requiring the highest precision.
They offer ±0.1mm position accuracy and ms level
response
times.
5. BRS PROSES Valve Solutions
As BRS PROSES, we offer comprehensive valve solutions for your
industrial
hydraulic systems:
- Standard and custom valve block
manufacturing
- Proportional and servo valve
integration
- Valve revision for existing
systems
- Technical consulting and
training
- Original spare parts supply
