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Open vs. closed hydraulic systems: what’s the difference?

Hydraulic systems can be either open or closed, each offering distinct advantages and applications. Power Team delves into the key differences between open and closed hydraulic systems, showcasing their respective designs, functionalities, and suitability for diverse engineering needs.

Hydraulic systems leverage the properties of hydraulic fluid, usually oil, to transmit power from one point to another. The fluid is pressurised by a pump, and is used to perform mechanical work, such as lifting, pushing, or rotating components within the machinery.

Open Hydraulic Systems:

  • Design: In an open hydraulic system, the fluid reservoir is open to the atmosphere. The hydraulic pump draws fluid from the reservoir, and excess fluid not consumed by actuators or motors is directed back to the reservoir, creating an open loop.
  • Functionality: The pump in an open system provides a continuous flow of hydraulic fluid, regardless of whether the actuators are in use. As the fluid circulates through the system, it returns to the reservoir, allowing for a constant fluid supply.
  • Applications: Open systems are commonly found in applications where constant fluid flow is acceptable, such as in mobile equipment like tractors and construction machinery. They are generally less complex and more straightforward in design.

Closed Hydraulic Systems:

  • Design: Closed hydraulic systems, on the other hand, operate in a closed loop. The hydraulic fluid circulates in a closed circuit, with a pump providing pressure to move the fluid through the system, and a motor or actuator converting that hydraulic energy back into mechanical work.
  • Functionality: Closed systems offer precise control over fluid flow. The pump only operates when needed, and the flow direction can be easily reversed. This makes closed systems more energy-efficient, as the pump doesn’t continually operate at full capacity.
  • Applications: Closed systems are prevalent in applications where energy efficiency and precise control are critical, such as in industrial machinery, aerospace systems, and manufacturing processes. They are well-suited for tasks requiring varying levels of force and speed.
  • Closed Hydraulic Systems:

Distinguishing Factors between an open and closed system:

  • The choice between an open and closed configuration depends on the specific needs of the application. Whether simplicity and continuous flow in open systems or precision and energy efficiency in closed systems, understanding the differences is crucial for engineers and technicians striving to optimize hydraulic performance in diverse industrial settings.
  • If you are unsure of which system you require for your specific needs and industry, contact Power Team for expert advice on all things hydraulics from uses, components and systems.