Open Center Hydraulic vs Closed Center Hydraulic [Key Differences]
Open center hydraulic systems are suitable for applications that require frequent and rapid movements, while closed center hydraulic systems are preferred when precise control and slower movements are needed.
In this article, we will do a detailed comparison between Open Center Hydraulic and Closed Center Hydraulic.
Open Center Hydraulic System
A hydraulic system with an open center is one in which, when the control valve is in the neutral position, fluid flows continuously through the system. This means that the hydraulic pump continues to pump hydraulic fluid even when the equipment is not in use.
How does an open center hydraulic system work?
An open center hydraulic system has three essential parts: a pump, a valve, and an actuator. The pump draws hydraulic fluid from a reservoir and pressure-feeds it to the valve.
The valve directs the flow of fluid to the actuator, which transforms the hydraulic pressure into mechanical force.
The system normally has an open valve, allowing hydraulic fluid to flow freely through the system. When a control is turned on, the valve sends hydraulic fluid to the appropriate actuator to move a part of the machinery or equipment.
In general, low-pressure operations like lifting and moving loads use open center hydraulic systems such as: Log splitters, Dump trucks, Snow plows, Construction equipment such as backhoes and loaders.
Closed Center Hydraulic System
A closed center hydraulic system is a type of hydraulic system in which the fluid is not flowing through the system when the control valve is in neutral.
Instead, the control valve’s neutral position causes the hydraulic pump to stop pumping, preventing heat buildup and minimizing wear on the hydraulic parts.
How does a closed center hydraulic system work?
A closed-center hydraulic system uses a hydraulic fluid loop to power machinery or equipment. It has several key components, including a pump, a valve, an actuator, and a pressure relief valve.
The valve is typically closed at rest and opens when a control is turned on, allowing hydraulic fluid to flow to the actuator. The actuator converts the hydraulic pressure into mechanical force. When the control is released, the valve returns to its closed position.
Application:
Closed center hydraulic systems are used in applications where the flow is intermittent and the pressure continuous.
These systems can be found in various types of machinery and equipment such as excavators, bulldozers, cranes, forklifts, agricultural machinery like tractors and harvesters, mining equipment like loaders and drills, road construction equipment like asphalt pavers and rollers, and industrial machinery like presses and injection molding machines.
Differences between an Open Center Hydraulic System and a Closed Center Hydraulic System
1. Components
The components of open center hydraulic and closed center hydraulic systems are similar. Both systems consist of a reservoir, a pump, a control valve, hydraulic lines, and actuators.
Closed center hydraulic systems require additional components, such as a pressure-compensated flow control valve, an accumulator, and a pressure relief valve, to ensure the system’s efficiency.
2. Fluid Flow
The manner in which hydraulic fluid flows through the system is the primary distinction between open-center and closed-center hydraulic systems. Even when there is no need for power, hydraulic fluid is constantly flowing through an open center system.
In a closed center hydraulic system, power is only delivered when necessary because the hydraulic fluid does not flow until the control valve is opened.
3. Cost
Hydraulic system costs vary depending on a number of variables, including the system’s size, complexity, and intended use.
A typical open center hydraulic system can cost anywhere between $1,500 and $5,000. In contrast, the cost of a closed center hydraulic system ranges from $4,000 to $12,000.
4. Energy Efficiency
Since power is only supplied when necessary, closed center hydraulic systems typically use less energy than open center hydraulic systems.
In an open center hydraulic system, hydraulic fluid is constantly flowing, which can result in energy waste.
5. Control
Open center hydraulic systems provide better control than closed center hydraulic systems because they allow for a finer degree of control. This is due to the system’s constant flow of hydraulic fluid, which enables the actuator to be controlled more precisely.
6. Noise
Closed center hydraulic systems are generally quieter than open center hydraulic systems because there is less hydraulic fluid flowing through the system. This may be a crucial consideration in applications where noise is an issue.
7. Response Time
Generally speaking, closed center hydraulic systems respond more quickly than open center hydraulic systems. This is because a closed center system’s constant pressure means that it is constantly prepared to react to changes in the input signal.
On the other hand, in an open center system, the system must first reach a certain level of pressure before it can react to changes in the input signal. As a result, compared to closed center systems, open center systems react more slowly.
8. Safety
Closed center hydraulic systems are generally considered to be safer than open center systems. This is because a closed center system’s constant pressure means that it is always prepared to respond to changes in the input signal.
Contrarily, in an open center system, the pressure doesn’t exist until the valve is opened. This means that if there is a leak in the system, the pressure could drop to zero and cause the machinery to move unexpectedly.
Additionally, a closed center system’s pump is always operating against a load; as a result, if the load is removed, the pump will turn off on its own, protecting the equipment.
However, in an open center system, even if the load is removed, the pump will still run, potentially damaging the equipment.
Closed Center Hydraulic Vs Open Center Hydraulic [Comparison Summary]
| Open Center Hydraulic | Closed Center hydraulic | |
| Application | They are typically designed for low-pressure applications such as lifting and moving loads. | They are designed for high-pressure applications, such as heavy machinery and equipment. |
| Cost | Less expensive | More expensive |
| Design | They have simpler designs. | Their design is more complex. |
| Structure | They have a simpler structure compared to closed center hydraulic systems. | They require additional components, such as a pressure relief valve and a load-sensing valve, to regulate the pressure and flow of the fluid. |
| Control | More precise | Less precise |
Conclusion:
In conclusion, open center and closed center hydraulic systems have their own advantages and disadvantages, and the choice between the two depends on the specific application.
The choice between open-center hydraulic and closed-center hydraulic systems depends on the specific application.
Open center hydraulic systems are generally better suited for applications where precise control is required, such as agricultural equipment or construction machinery.
Closed center hydraulic systems are better suited for applications where energy efficiency is a concern, such as mobile equipment.
Understanding the differences between the two systems can help you make an informed decision and choose the one that best meets your needs.
