Let's take a closer look at the difference between hydraulic and pneumatic machines.
What is a pneumatic system?
(pneumatic system)
The pneumatic system uses pressurized air to influence mechanical movement. It is based on pressure principles and is powered by compressed air or gas. The system has several components, including air tanks, standard cylinders, compressors, hoses and transition lines.
Applications: Pneumatic systems are commonly used in medical applications (dentistry), food manufacturing, construction, robotics, mining, pharmaceuticals and more. This system was primarily used for shock absorption because the compressed gas makes it less susceptible to shock damage.
What is a hydraulic system?
(hydraulic system)
The hydraulic system uses pressurized liquids to transfer mechanical energy and transform that energy into useful work. Like the pneumatic system, hydraulics also use valves for the speed and force of the actuators.
Applications: Hydraulic systems present the risk of oil leaks from valves or hoses. Therefore, the system is not used on anything that can be ingested. Common industrial applications of a hydraulic system include elevators, dams, amusement parks, hydraulic presses, turbines, aircraft flaps, wheelchairs, hydraulic lifts, and more.
Pneumatic and hydraulic systems: what’s the difference?
(pneumatic system vs hydraulic system)
The main difference between these two systems is that hydraulics use liquids, which do not compress, and pneumatics use gases, which can compress. This affects how both systems are built and how they work.
Hydraulics are generally larger and slower. However, they offer better power and accuracy. On the other hand, pneumatic systems are more compact and faster. But they offer less strength and precision.
Here are some other differences between pneumatic and hydraulic systems.
#1 Strength
For high-strength applications, hydraulics are best. This system uses an incompressible liquid medium with a high mass density. Therefore, hydraulic devices can create higher pressure levels and utilize them to transmit energy for use. Most industrial equipment requires 1,000 to 5,000 pounds per square inch (psi). But some hydraulic machines operate at 10,000 psi or more.
Pneumatic systems use gases with a low mass index. Gases can easily be compressed to several hundred psi. This is why equipment that can operate between 80 and 100 psi uses pneumatic systems. This system cannot be used to operate heavy equipment. Furthermore, compressed air may fluctuate unexpectedly, making operation unstable.
#2 Hygiene
In the field of hygiene, pneumatics wins points, as the only thing that is lost in this system is air. When gases are compressed, they are cleaned of metal particles, oil or water within the system. Many environmentally conscious companies use pneumatic systems to follow greener manufacturing practices.
Pneumatic systems are also installed in clean rooms, such as pharmaceutical laboratories and food industries. These environments cannot use hydraulic machines with leaks, as there will be a risk of contamination.
Plumbing involves the possibility of oil or water leaks through worn hoses or faulty seals. It can contaminate the industrial environment and corrode hardware. If you use hydraulic systems, you also need storage tanks and proper waste disposal.
#3 Speed
Pneumatic systems have better speed than hydraulic ones. This is because the compressed air flow rate is high. It can release energy quickly, allowing actuators to move at high speed. Air flows quickly through the tubes because it has a lower mass density. Pneumatic actuators offer better productivity because they can achieve a higher duty cycle and high cycle speeds. The rapid movement of the cylinder becomes more useful because the equipment is also available in very small sizes.
After the compressed air is exhausted, the valves and pneumatic cylinders can quickly change direction. The system does not require additional disposal. In contrast, hydraulic systems are slower because they use water or oil. Compared to air, hydraulic or mineral oils have greater resistance. Here, the viscosity of the oil slows down the system.
Although the power of hydraulic fluid can help develop better force and pressure, they are not as fast as air. This is why these systems take longer to work. In the event of a leak or emergency, hydraulic fluids must be adequately vented and redirected to their reservoir.
#4 Energy
Several factors need to be considered when comparing hydraulic and pneumatic systems in energy consumption. But both systems need electrical systems to power them. Continuous operation of the air compressor is necessary for the correct operation of pneumatic machines. Furthermore, the air supply requires constant replenishment as it cannot be recycled. Therefore, energy consumption is high.
Furthermore, the system loses energy due to the heat produced during the compression process. But you can make your pneumatic system much more energy efficient through several measures. Instead, the same hydraulic fluid power can be used repeatedly after initial start-up. With a good filtration system, you can make your plumbing energy efficient.
But you still need electricity to run the pump. Unfortunately, most of the energy consumed by pumps is wasted. This happens because hydraulic fluids must be in constant circulation to maintain system pressure.
#5 Security
Among pneumatic and hydraulic systems, pneumatics are safer. This is because compressed air leaks are not dangerous. But the gases used in portable equipment can be dangerous.
#6 Complexity
Hydraulic systems are more complex because they are larger. These systems have fewer moving parts and can be easily controlled using levers or buttons. Plumbing is also complex engineering that requires valves, hoses, and a pump. These systems must be connected to an external power source and store the liquid medium.
Various hydraulic applications in a factory can be controlled through a centralized power unit. Newer hydraulic systems have better power, speed and pressure systems. In contrast, pneumatics is simple. Components are made from cheaper and less complex materials because the system can operate at lower pressure.
Furthermore, it is not necessary to take any precautions as the fluid is neither combustible nor corrosive. Lately, pneumatic machines have been used in a variety of pneumatic equipment.
#7 Maintenance
The fluid medium in pneumatics is air, so the system is easier to maintain. But the system requires regular preventative maintenance and inspection to function effectively. Common maintenance on the pneumatic system includes checking the seals for air leaks. It is important to regularly clean and replace the filter-regulator-lubricator units.
On the other hand, the hydraulic system is more likely to suffer from corrosion. These systems need regular monitoring to know how much fluid has affected the pipe. Water like hydraulic oil can cause oxidation, while others can cause corrosion.
Therefore, regular maintenance and checks of critical components such as valves and hoses are necessary to keep the system running.
When to use hydraulic and pneumatic systems
Hydraulic systems are best for heavy lifting equipment and higher force applications. In comparison, pneumatic devices are great for mechanical and light engineering applications.
Difference Between Hydraulic and Pneumatic Actuator
Hydraulic actuators use fluid and can produce great force to handle higher pressures. These systems can produce 25 times more force than a pneumatic cylinder. Because hydraulic or mineral oil is a relatively incompressible liquid medium, actuators can maintain torque without the continuous application of fluid pressure from the power source.
But leaky hydraulic actuators can cause contamination. It can also damage internal and external work parts. These systems can be quite noisy, even with noise reduction equipment. On the other hand, pneumatic actuators require less energy. They are more consistent and reliable. As they use compressed air, pneumatic motors are not necessary.
But these actuators can float and lose pressure because the air can be compressed. Furthermore, the pneumatic actuator and air compressor must be placed close to each other so that the system can operate continuously. At extremely low or high temperatures, pneumatics can be more reliable than hydraulics.
Cost of pneumatic and hydraulic systems
The cost of electricity required to operate a pneumatic and hydraulic system can also act as an important differentiating factor. Pneumatic systems seem cheaper because they are more electrically efficient. But these require regular maintenance, which can affect productivity and efficiency.
Hydraulic systems have a higher initial cost. Equipment durability plays an important role when purchasing a plumbing system. You can make a system more durable with regular preventive maintenance. You can control the cost of your plumbing simply by using a central power supply, which can run multiple pieces of equipment. A central power source can reduce costs and increase machine performance.
Conclusion
Hydraulics and pneumatics work on the same principles, but have unique applications, features and characteristics. As pneumatic systems use pressurized air, there is no risk of oil leaks. But these systems do not have better resistance, as the compressed air can fluctuate unexpectedly.
On the other hand, hydraulics use oil or water as fluid, which can be dangerous in the event of a leak. These systems cannot be installed in industries that produce edible items. Both systems have some advantages and disadvantages. Therefore, caution must be exercised to maintain safety.
