There is not a single method of power transmission that is the best choice for all applications, and some applications can even incorporate a combination of systems.
Fluid power is a term used to describe hydraulic and pneumatic systems, as both of these technologies use a fluid to transmit power by simply moving it from one location to another, in this case the movement of liquid or gas. Mainly, the fluid used is oil, as a liquid, and compressed air, as a gas.
Power transmission, relating to electrical methods of power, relays the power used to control a motor which in turn allows for the speed and torque to be regulated.
Comparison of electrical, hydraulic and pneumatic systems can be compared to aspects such as an energy source, energy storage, energy cost, distribution system, linear actuators, rotary actuators and controllable force.
Throughout this article we are firstly going to consider the features of the systems themselves, then look at how the internal linear actuators work.
An actuator is simply a component of a machine that moves or controls loads and mechanisms. The actuator is operated by energy, either pressurised fluid, air or electricity, typically sourced by utilising a pneumatic, hydraulic or electric pump. The energy is then converted into a motion or force to achieve movement or control.
To understand the differences between pneumatic, hydraulic and electric actuators, we need to look at the mechanics of how each system derives its force.
Pneumatic linear actuators consist of a piston inside a hollow cylinder. Pressure from an external pneumatic pump moves the piston inside the cylinder, and as pressure increases the cylinder moves along the axis of the piston, creating a linear force. The piston returns to its original position by either a spring back force or fluid being supplied to the other side of the piston.
Hydraulic linear actuators operate similarly to pneumatic actuators, but an incompressible liquid supplied from a pump moves the cylinder, rather than pressurised air.
An electric linear actuator converts electrical energy into speed and torque. A mechanically connected electric motor turns a lead screw, and as the screw rotates, the nut is driven along the threads, moving in the direction the screw rotates.
Now that the functions behind the difference between the three types of actuator are clear, along with each of their beneficial features, you can match your requirement to HTL Group’s range of pumps.
For instance, when working in a hazardous environment, pneumatic and hydraulic systems should be considered over electrical. However, for an accurate level of torque, electrical systems are quicker and more user friendly.
The same trade-offs apply directly to choosing between hydraulic, electric and pneumatic torque wrenches, since each is built around one of these three actuator types. HTL Group’s hydraulic vs electric torque wrench guide covers that comparison specifically.
With a wide range of pumps available:
HTL Group can supply equipment to suit your hire and sale requirements.
Pneumatic actuators are generally the safest choice for hazardous or flammable environments, since they avoid hazardous materials and create no magnetic interference. Electric actuators are not suited to hazardous environments in the same way.
Electric actuators offer the highest precision control of the three types, making them well suited to applications where accurate, repeatable torque matters more than raw force.
Yes, some applications combine more than one system where it suits the job, for example using an electric motor to drive a hydraulic pump. The right combination depends on the specific application’s environment, force and control requirements.
Hydraulic, electric and pneumatic torque wrenches are each built around the actuator type of the same name, so the trade-offs described here, force, precision, hazardous area suitability and maintenance, apply directly. HTL Group’s torque wrench guide and hydraulic vs electric torque wrench guide cover this in more product-specific detail.
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For further information or to get an instant quote of HTL Group’s range of pneumatic, hydraulic and electric pumps, call +44 (0)1670 700 000 or email info@htlgroup.com.
