In scenarios such as dump truck lifting, warehouse handling, and cargo loading and unloading, single acting hydraulic power units are often used to complete one way actions like pushing and lifting. Now, let’s focus on the single acting hydraulic power unit and learn every detail about it!
What is a Single Acting Hydraulic Power Unit?
A single acting hydraulic power unit is a hydraulic power pack that provides power for a hydraulic system. It achieves one-way mechanical movement by driving a hydraulic single acting cylinder with the pressure of hydraulic oil. The return process is accomplished through external forces such as spring elasticity, load weight, or gravity.
The Key Components of the Single Acting Hydraulic Power Unit
Hydraulic Motor
The hydraulic motor can convert electrical energy into mechanical energy, providing a continuous driving force for the operation of the hydraulic pump. In fixed equipment and industrial environments, 220V or 380V AC motors are more commonly used.
In scenarios where mobile devices are used or where power supply is limited, most of the devices adopt DC motors (DC 12V/24V/48V). This type of motor usually adopts S2、S3 intermittent working system. It perfectly adapts to the low-frequency action requirements of single acting devices and reduces energy consumption while ensuring power output.
Hydraulic Pump
Hydraulic pumps can convert the mechanical energy transmitted by motors into hydraulic energy. The motor drives the pump to operate, causing the pump to draw oil from the oil tank. Then, it is pressurized and output, pushing the high-pressure hydraulic oil into the system. The flow output of the hydraulic pump determines the operating speed of the hydraulic single acting cylinder.
The most commonly used single acting hydraulic power unit is the gear pump. It has a simple structure, low cost, and strong anti pollution ability. It is suitable for construction machinery, logistics equipment operating under medium and low pressure conditions.
If your system requires high-pressure output, you can choose a hydraulic piston pump or a vane pump. However, they have higher requirements for the cleanliness of the oil.
Fuel Tank
The hydraulic fuel tank is used to store hydraulic oil. At the same time, it also undertakes the responsibilities of maintaining the quality of the oil and dissipating heat in the system. The fuel tank capacity is usually 3L to 100L, and you can choose materials such as steel, aluminum, or plastic.
Modern fuel tank designs focus on optimizing the internal structure. The flow, compression, and friction of hydraulic oil in the system will generate heat. The internal partition in the box separates the return oil area from the oil intake area, which allows the hot return oil to flow along the box walls to enhance heat dissipation.
At the same time, the fuel tank provides space for impurity precipitation and air separation to prevent air bubbles from entering the hydraulic pump and causing cavitation.
Hydraulic Valves
The single acting hydraulic power unit achieves precise control of oil flow direction, pressure, and flow rate by integrating multiple valves. These valves are usually arranged compactly in the form of valve blocks to reduce the risk of leakage.
- Pressure control valve: When the oil pressure in the system exceeds the set value, the pressure control valve will open automatically. It will release the excess oil back to the oil tank or the circuit to prevent the pressure from continuing to rise. This avoids damage to pumps, pipelines, hydraulic cylinders.
In addition, when the pump continues to supply oil and the system needs to maintain stable pressure, the pressure control valve can keep the outlet oil pressure within the preset range. The pressure will not keep increasing due to the continuous supply of oil by the pump.
- Throttle valve: It controls the speed of hydraulic cylinder action by adjusting the flow rate of hydraulic oil through the valve port, making the system action smooth and controllable.
- Directional control valve: It determines the path and direction of hydraulic oil flow, thereby controlling whether the hydraulic cylinder extends or stops.
How does a Single Acting Hydraulic Power Unit Work?
When the single acting hydraulic power unit receives the operation command, the motor starts first. It converts electrical energy into mechanical energy and drives the hydraulic pump to operate through the drive shaft.
The hydraulic pump utilizes changes in the internal sealed volume to create a local vacuum and draws filtered hydraulic oil from the oil tank. Then, the oil is pressurized through gears to provide a high-pressure oil source for the system. This completes the conversion of mechanical energy to hydraulic energy.
The pressurized hydraulic oil is guided to the single acting hydraulic cylinder through pipelines and valves. When the hydraulic cylinder receives high-pressure oil, the oil pressure pushes the piston and piston rod to extend. Then it will drive external devices to complete one-way actions such as lifting and pushing.
When the work operation is completed, the motor stops running, the hydraulic pump stops supplying oil, and the valve group switches to the pressure relief state. The high-pressure oil inside the hydraulic cylinder flows back to the oil tank through the return pipeline. The external force pushes the piston back to its original position.
Types of Single Acting Hydraulic Power Units
AC Type
The AC single acting hydraulic power unit operates on the AC power supplied by the industrial grid. It is the mainstream choice in fixed equipment scenarios. The power output of the AC type device is stable. It can withstand medium to high intensity loads for a long time and is suitable for working conditions that require continuous or high-frequency unidirectional action.
When working, the AC motor is connected to the power grid for power supply, without the need for additional energy storage equipment. The AC motor has a long service life and low maintenance cost.
It can also be powered by the power grid without being limited by battery life. It is especially suitable for scenarios with a stable power supply, such as factory workshops and fixed work areas in warehouses.
However, the AC type single acting hydraulic power unit relies on a fixed power supply interface and cannot operate in an environment without an electrical grid. When it is started, it will cause a certain impact on the grid voltage. You need to equip a suitable power supply protection device.
DC Type
The DC single acting hydraulic power unit is driven by a direct current power supply. It is widely used in mobile devices, such as vehicle tailboards, mobile lifting platforms, and field operation equipment.
The DC type single acting hydraulic power unit can be directly connected to the battery installed on the equipment or the on-board power supply. The DC motor has a fast startup response and can quickly complete the pressure increase and power output of the hydraulic pump. And the starting current is relatively gentle, with less loss to the energy storage power source.
In addition, the DC type device has a more compact overall structure, with a smaller volume and lighter weight. It is convenient for integration into mobile devices with limited space.
However, compared to the AC type, the continuous output capacity and power-bearing capacity of the DC single acting hydraulic power unit are limited.
The Advantages of the Single Acting Hydraulic Power Unit
Simple Structure and Easy Maintenance
The single acting hydraulic power device only needs to achieve one-way hydraulic drive, so the number of its core components is reduced. And there is no complex bidirectional oil circuit design, making the overall structure simpler and compact.
The manufacturing process of components such as hydraulic single-acting cylinders and valve groups is mature, and the number of fault points is relatively small. For daily maintenance, you only need to focus on basic aspects such as the cleanliness of the oil and the condition of the seals.
Economic Energy Conservation
The structure of the single-acting hydraulic power unit is simple, which can help you reduce the initial procurement cost. The return action of the single acting hydraulic power unit relies on external forces such as springs and gravity.
It only consumes energy during the one-way working process. This design can significantly reduce energy consumption in daily use. In the long run, this energy-saving feature means that you can reduce your operating costs.
Safe and Reliable
When the system loses power or there is a failure in pressure relief, the hydraulic single acting cylinder will automatically return to its initial position under the action of external force. This avoids dangerous situations such as load retention and equipment jamming and reduces the risks of work safety significantly.
Meanwhile, the simplified oil circuit design has reduced the risk of oil leakage. This can reduce the probability of equipment failure caused by leakage and also avoid environmental pollution.
Quick Response and High Operational Efficiency
The hydraulic circuit of the single acting hydraulic power unit is simple and the oil flow path is short. After the motor is started, it can quickly drive the hydraulic pump to complete the pressure increase and power output.
Meanwhile, the return journey does not require hydraulic drive, which shortens the duration of each working cycle. This improves the overall efficiency of the work.
The Application of Single Acting Hydraulic Power Units
Self Dumping Trailer, Dump Truck
The single acting hydraulic power unit is an ideal component for the hydraulic lifting and dumping system of this type of vehicle. It can perfectly meet the frequent unloading operation requirements of these vehicles.
During operation, the single acting hydraulic power unit can quickly provide stable oil pressure that makes the tipping bucket to be lifted smoothly and completes the unloading task. After unloading, there is no need for additional hydraulic power, and the tipping bucket can automatically fall back and reset by its own gravity.
Lifting Platform, Scissor Type Elevator, Tail Plate
For devices that only require lifting and lowering functions, single acting hydraulic power units can be perfectly adapted. It can provide a continuous and stable lifting force for the equipment and keep a smooth and safe operation process. The descent or reset action does not require hydraulic pressure and can be accomplished by the load’s own gravity.
Light Handling Equipment, Material Loading and Unloading System
In scenarios such as warehouse management, logistics transportation, and cargo loading and unloading, many devices typically only require a single direction of force output. At this point, a simple single acting hydraulic power unit is sufficient to meet your operational requirements fully.
It can provide sufficient hydraulic force to keep the efficient advancement of material processing. The advantages of simple structure and compact size allow the equipment to operate flexibly in a limited space. At the same time, it reduces the difficulty and cost of daily maintenance. When palletized loads are placed into warehouse racks, rackable plastic pallets can provide a reusable load base when their rack capacity matches the support layout and cargo weight.
Small Portable Devices and Mobile Machinery
Small trailers, portable lifting devices usually have strict requirements for device volume and weight. The single acting hydraulic power unit is a good solution.
The structure is simple and compact, with few components, making it easy to install in small spaces. And the maintenance process is simple. You can use it in outdoor work, emergency rescue, and other scenarios without a fixed power source.
Single Acting Hydraulic Power Unit VS Double Acting Hydraulic Power Unit: A Simple Comparison
Working Principle
- The single acting hydraulic power unit provides one-way hydraulic drive. It only has one working oil port. It uses hydraulic oil pressure to push a single acting hydraulic cylinder to complete one-way actions such as extension and lifting.
The return journey relies entirely on external forces, such as the weight of the load, spring force, or mechanical structure tension. It does not require additional hydraulic power.
- The double acting hydraulic power unit has two independent oil circuits. There is an oil port at each end of the double acting hydraulic cylinder. By switching the directional control valve, pressure oil can enter both sides of the piston alternately. The extension and retraction of the piston rod are both driven by hydraulic oil.
Structure
- The structure of a single acting device is relatively simple. It only requires one oil port, with fewer components, pipelines, and valves.
- In order to achieve bidirectional switching and precise control of the oil circuit, the double acting hydraulic power unit requires more complex valve groups and oil circuits.
Maintenance
- The single acting hydraulic power unit has a simple structure and fewer potential failure points. The maintenance is usually more intuitive and convenient.
- The double acting device requires relatively higher professional maintenance due to its more components.
Application
- Single acting hydraulic power devices are suitable for equipment that does not require complex actions and has limited space. For example, you can use it for lifting dump trucks, lifting truck tailboards, hydraulic jacks, scissor lifts, and so on.
- The double acting device is suitable for working conditions that require precise control of bidirectional speed and position. For example, you can use it for the pushing and pulling of the excavator bucket, the extension and retraction of the hydraulic mechanical arm, and the grasping and releasing actions of the industrial robotic arms.
FAQ
What are the Precautions when Installing a Single Acting Hydraulic Power Unit?
First of all, you need to ensure that the size and installation orientation of the device match the space you have reserved. Then, before installing valves and other components, you must clean the oil tank, hydraulic hoses, and fittings. And check the sealing ring to ensure that it is intact and lubricated correctly before installation.
Finally, all pipeline connections must be secure, and hoses must meet the minimum working pressure requirements of the system.
What should be Noted when Using Single Acting Hydraulic Power Units in High or Low Temperatures?
In high-temperature environments, it is necessary to strengthen the heat dissipation of the fuel tank. You can increase the heat dissipation area of the fuel tank and equip it with a cooler. Meanwhile, you need to choose high-temperature resistant hydraulic oil.
Low temperature environments require the use of oil with good low-temperature fluidity. Before starting the device, you can preheat the oil by running the motor for a short period of time to avoid forced loading.
What could be the Possible Reason for the Llow Action Speed of a Single Acting Hydraulic Power Unit?
The slowdown in the operation speed of the single-acting hydraulic power unit is usually related to insufficient system flow. Common reasons include hydraulic pump wear, seal failure, pipeline or joint leakage, and clogged oil tank filters.
When troubleshooting, you can first check the oil condition, filter cleanliness, and pipeline sealing. Then check the output pressure of the hydraulic pump, and finally check whether the valve components are working properly.
Final Thoughts
Target Hydraulics is a professional manufacturer of hydraulic equipment with over 10 years of experience. We are committed to providing you with high quality single acting hydraulic power units that are economical, energy-saving, safe, and stable.
In addition to the standardized equipment that meets the routine operational power requirements, we can also provide customized solutions based on your working conditions, installation space, and load requirements. Feel free to contact us at anytime!
