Like everyone knows, an actuator is a machine component that converts energy into motion. The actuators play a significant role in moving and controlling a mechanism or system. In general, we can categorize actuators into three: hydraulic actuators, pneumatic actuators, and electric actuators. This categorization depends on what kind of energy is converted to mechanical motion. In the hydraulic actuator, pressurized hydraulic fluids are used; in pneumatic actuator, compressed gases are used; and in the electric actuator, electrical energy is converted to motion. Comb drive, hydraulic cylinder, screw jack, stepper motor, electric motor, etc… are common examples of actuators. In this article, we can differentiate between the hydraulic actuator and pneumatic actuator, that are mostly used in different industries.
The hydraulic actuator is a popular category that has applications in heavy-duty operations and is suitable for construction, marine, offshore, transportation, and military industry. In hydraulic actuators, any incompressible hydraulic fluid(normally any oil that exhibits fluid properties) is used and they are pressurized to the maximum so that, it effectively converts hydraulic energy into mechanical force. This actuator can exert a large force and the output will be in terms of linear, rotatory, or oscillatory motion.
If considering the drawbacks of a hydraulic actuator, the primary concern is leakage. Leakage of hydraulic fluid can make the workspace dirty and will result in workspace accidents. Other concerns are high initial investments and maintenance requirements.
The pneumatic actuators utilize compressed gases to convert energy into motion. The basic working of both hydraulic and pneumatic actuators are similar. In pneumatic actuators, the piston moves with the pressure of compressed gases, and this piston movement converts the pneumatic energy to corresponding rotary or linear motion, which depends on the attached mechanism to the piston. Simplicity, durability, ease of installation, and safety are the key benefits of pneumatic actuators. Some common applications of the pneumatic actuator are grippers, tie-rod cylinders, pneumatic artificial muscles, vacuum generators, etc…
Pneumatic actuators have some limitations. Among them, the limited strength and work capacity is the first point to be considered. Also, pneumatic actuators have a shorter life cycle compared to other actuators.
DIFFERENCE BETWEEN PNEUMATIC AND HYDRAULIC ACTUATORS.
The basic operations involved in both hydraulic and pneumatic actuators are similar and in some instances, both can be used. If considering the difference between two types, the important one is the medium used. As discussed earlier, in hydraulic pressurized hydraulic fluid is used and in pneumatic actuator, compressed gases are used for conversion into mechanical motion. Other significant differences are listed below.
- Pneumatic actuators are comparatively less efficient than hydraulic
- Hydraulic actuators can produce force 25 times greater than pneumatic
- For operations that require lower pressure and speed, pneumatic actuators are preferred.
- Pneumatic actuators can easily meet mechanical safety requirements.
- Hydraulic actuators are suitable for high force applications whereas, pneumatic actuators can be used for extreme temperature applications.
- Horsepower-to-weight ratio is greater for hydraulic motors
- Hydraulic actuators have the ability to keep constant force and torque.
- Hydraulic actuators provide precise linear motion compared with pneumatic
- Pneumatic actuators are cost-effective and require minimum maintenance.
- For repeated operations, pneumatic actuators are mostly preferred
- Pneumatic actuators provide high-speed motion compared with hydraulic actuators.
- Pneumatic actuators are preferred for hazardous environments.
Also Read : Hydraulic Cylinder