Hydraulic Symbols Library

Effectively communicating complex hydraulic system design is crucial for the success of any project. Standardised hydraulic symbols, defined by ISO 1219-1:2012, form the backbone of clear communication in hydraulic engineering. These symbols act as a universal language, enabling engineers to represent hydraulic components, flow paths, and their connectivity.

Let’s learn more about the most common symbols, how they work, and their importance in creating accurate hydraulic schematics.

Understanding Hydraulic Symbols

Hydraulic symbols are graphical representations used in hydraulic schematics to denote various components, such as valves, pumps, motors, and cylinders. Each symbol conveys critical information about fluid flow, pressure, and the function of components within a hydraulic circuit.

These symbols follow international standards set by ISO 1219-1, ensuring consistency across industries worldwide. Learning to read hydraulic schematics is a valuable skill for engineers, technicians, and anyone involved in designing or maintaining hydraulic systems.

Key Components and Their Symbols

Valves

Valves control the flow and pressure of hydraulic fluid within a system. Different types of valves include:

• Directional Control Valves: Represented by rectangles with arrows indicating the direction of flow.
• Check Valves: Shown as triangles with a line, allowing fluid to flow in one direction while blocking the other.
• Flow Control Valves: Represented by a line and arrow, these regulate the fluid flow rate.
• Pressure Valves: These ensure the system doesn’t exceed safe pressure levels, typically depicted with spring-loaded symbols.

Pumps and Motors

• Hydraulic Pumps: Shown as circles with arrows pointing outward, pumps pressurise hydraulic fluid to power the system.
• Hydraulic Motors: Similar to pumps, but with inward arrows, representing fluid-driven motion.
• Pumps and Motors together ensure efficient conversion of energy within a hydraulic system.

Cylinders

• Hydraulic Cylinders convert fluid pressure into linear motion.
• Cylinder Symbols use rectangles with internal arrows to show the direction of the force applied.

Reservoir and Accumulator

• Hydraulic Fluid Reservoir or Tank: Often represented as a rectangle or oval, indicating where fluid is stored.
• Accumulators: Shown with a circle, these store pressurised fluid to maintain system stability.

Hydraulic Circuit Basics

A hydraulic circuit includes interconnected components like valves, cylinders, and pumps to perform specific functions. Understanding the schematic symbols used in these circuits helps engineers identify potential issues and optimise performance.

Directional Control in Circuits

The directional control valve plays a pivotal role, directing the flow of hydraulic fluid through various paths in the system.

• Arrows in the symbol represent the flow path.
• Pilot lines, often shown as dashed lines, indicate control signals.

Fluid Flow and Pressure Management

Fluid flows through the system under pressure generated by the pump. Key elements like filters, coolers, and heat exchangers ensure the fluid remains clean and maintains the correct operating temperature.

Common Hydraulic Symbols and Their Representations

• Arrow: Indicates the direction of flow.
• Triangle: Represents fluid flow or pressure direction.
• Rectangle: Often denotes valves, showing different flow positions.
• Circle: Used for pumps, motors, and accumulators.

These symbols, combined in hydraulic schematics, represent various components and their roles in a system. Common symbols like lines and shapes connect components, forming a complete system overview.

Reading Hydraulic Schematics

Understanding the symbols and their arrangement is crucial to reading hydraulic schematics. Start by identifying the primary components, such as the pump, valves, and actuators. Then, follow the flow path shown by arrows to see how hydraulic fluid moves through the circuit.

Why Standardised Symbols Matter

Using standardised symbols ensures clear communication between engineers and technicians. This consistency minimises errors and simplifies troubleshooting when working on systems with complex fluid power demands.

At Hydrastore, we’ve compiled a library of hydraulic symbols for various products in our catalogue. These files are compatible with leading design software like HydraSym by Paro Software, making it easy to create accurate schematics.

Practical Applications

Hydraulic symbols are widely used in:

• Designing and troubleshooting hydraulic systems.
• Training technicians and engineers.
• Creating documentation for complex systems.

Need Help With Hydraulic Symbols?

Our team at Hydrastore is ready to help. Contact us today at 01427 874445 or email sales@hydrastore.co.uk to discuss your project requirements.

Hydraulic symbols are more than drawings—they represent the lifeline of a hydraulic system. Every detail contributes to efficient system operation, from fluid pressure to directional control.