Hydraulic systems
Hydraulic systems are closed systems which apply the laws of physics; in this case, the law of conservation of energy. These systems store energy by compressing a liquid (oil) in a closed container and from there the oil can flow in a predetermined direction. The oil is compressed by a pump usually driven by an electric motor or, in some cases, manually.
The uniqueness of hydraulic systems is the fact that they allow large forces to be released by investing relatively small forces at the start. This enables lifting heavy weights, for example the weight of the vehicle on the jack, by manually operating the hydraulic device. The effort required to operate the jack is small, but the weight that the jack lifts at the end of the road can be enormous.
Another application of hydraulic systems is the forklift, which is one of the most common and useful devices in industry and commerce. At the beginning of the twentieth century, the pallet was invented – a new form of loading and unloading goods on trucks or inside warehouses. The use of the pallet would not have been possible had it not been for the invention of the forklift at the end of the second decade of the last century. The operation of the forklift is made possible by using hydraulic systems.
Other uses of hydraulic systems:
Once the relatively simple process by which the hydraulic system is operated was understood, various experts began to adapt it for use in a wide variety of fields, such as:
- Hydraulic steering systems: Since the basic advantage of hydraulic systems is in creating great forces at the end of the process by applying small forces at the beginning, it can be utilized for better control of vehicles, especially heavy vehicles. This is how hydraulic steering systems replaced the good old manual steering.
- Steering systems in aviation: The forces required to control the flight gays are enormous; with the help of the hydraulic systems, the pilot exerts minimal forces on the steering stick and these forces are multiplied by thousands of times and control the plane’s steering systems.
- Mechanical engineering equipment could not have entered our world without the existence of hydraulic systems operating backhoes, tractors and trucks.
A brief explanation of a hydraulic motor and its features
Industry all over the world makes extensive use of hydraulic motors as well as hydraulic pumps, which are part of what most of us know as “hydraulic equipment”. A hydraulic motor, in order to be powerful and long lasting, needs to be suitable for pressure and load in the system as well as for the required working durations.
So what exactly is a hydraulic motor, and how do you choose the right one for your needs?
A hydraulic motor is a motor whose operation is carried out by high pressure oil flow. In a piston engine, the process of compressing the oil creates a massive pressure on the engine piston. As a result, the energy is continuously transferred to the linear motion of the motor pistons and by mechanical transmission this motion is converted into rotational motion of the motor shaft. In a rotary engine the flow of oil through a turbine causes a rotational motion of the turbine and the turbine rotates on an axis; usually, the turbine mirror is connected to a mechanical transmission that increases engine torque. This basic principle relies on the properties of oil – which is not compressible – and allows for a continuous transfer of energy.
Considerations for choosing a hydraulic engine
A hydraulic motor is the part responsible for moving machinery in industry, along production lines, and it is even used for the operation of elevators which many of us use on a daily basis. Some electric gates that are opened by scrolling are run by a hydraulic motor, and there are many more applications. Vehicles also use hydraulic engines – they are responsible for the operation of the vehicle’s brake system; they are used in aircrafts, submarines and in many other industrial, public and private applications. As its name implies, the hydraulic engine is the driving force of the entire system, hence its great importance in the operation of the overall hydraulic system.
Therefore, the choice of hydraulic motor should be made carefully, taking into account the purpose of its use:
The loads applied to it, the frequency of its use, the working temperature, the pressure and oil flow in the system, etc. In aviation there is also great importance to the weight and size of the engine.
Types of hydraulic motors:
- Star engine
• Gear motor
• Piston engine
• Rotor motor
A quick note about hydraulic pumps
A hydraulic pump is used to convert the rotational motion that reaches the pump shaft to a hydraulic power supply. A common hydraulic pump belongs to the category of pumps with positive pressure. This means that this type of pump works on the principle of a cyclical change in the volume of any cell: as the volume of the cell increases, oil (or another liquid) enters it and fills it. When the volume of the cell decreases the oil is pumped out, creating the force, or pressure. A hydraulic pump is most often driven by electric motors or diesel engines.
Hydraulic pump – choose wisely
There is a wide range of hydraulic pumps, such as: gear pumps, vane pumps, piston pumps. As mentioned, a hydraulic pump will allow for compression activity in a standard and smooth manner under heavy loads. When choosing a hydraulic pump, it is necessary to consider many factors such as: required loads, frequency of use, working temperature, pressures and flow rates.