Fluid power is a much more convenient and cost effective technology
Published on : Wednesday 03-03-2021
Shashank Gune, CEO, Techtonic Engineering.
Traditionally fluid power played an important role in automation. Has electrical actuation now taken over?
Fluid power systems started becoming a major driving force in the industry in the early 20th century. Rapid growth occurred post World War II, when the need was felt to increase the productive efficiency of various industrial processes. Further technological advancements took place in the last 3 decades which continue even today. The integration of electronics has spearheaded much of this growth into components and systems, moving from analog to digital electronics to network and wireless communication. These advancements in fluid power technology have made it more energy efficient, compact, sleek, user friendly and cost effective.
Many people were expecting electrical drives to take over completely from fluid power. However, this has not happened in practice, thanks to these technological advancements. In fact, the global market trends predict a decent growth at 5.3% CAGR for pneumatic actuators and 3.6% CAGR for hydraulic actuators over the next 3 years.
What are the advantages fluid power still offers vis-à-vis electromechanical drives?
There are a vast number of applications where pneumatics and hydraulics are preferred over electric drives. Hydraulic technology is particularly used in heavy duty applications, where brute force is required whilst pneumatic technology is chosen for lightweight, high-speed and comparatively low-cost applications. Generally speaking fluid power can offer better force-to-weight ratio than electrical drives.
Fluid power technology comes handy for applications where the motion duty cycle is not 100% because the accumulator in a fluid power system stores energy when the system is not moving. On the other hand, electric motors are employed in applications with continuous motion, such as conveyors.
In robotic pick & place applications, gripping is one of the most common functions. Pneumatics is often the preferred choice here for the reasons of cost and weight. Pneumatic hardware weighs less than servomotors thereby reducing the payload of the robot.
Another typical advantage of fluid power in robotic applications with many axes is that a single pump can provide power for multiple actuators. Thus, the pump can be mounted in the base location keeping the weight on the robotic arms as low as possible.
With fluid power, pressure can be held constant without applying significantly more energy. Driving an electric motor to apply constant torque could cause overheating.
Unlike electrical drives, pneumatics can tolerate rapid duty cycles without overheating and overloads simply cause pneumatic actuators to stall rather than burn out.
Fluid power is also a much more convenient and cost effective technology in applications requiring both pressure and position control. For example, press rolls in steel rolling, where heavy rollers are positioned above the work in process and then a controlled amount of pressure is applied on them.
There are also applications where particularly strong gripping forces are required. For example, in the foundry industry, for picking up hot billets. In these types of applications hydraulics is often the only technology that can be deployed.
Pneumatic technology offers benefits in clean environments such as food, pharma and electronics sectors.
In almost all industrial sectors, today’s fluid power components offer specific benefits to ensure efficient operation and lower cost of ownership.
Large vehicles and the automotive industry have accounted for much interest in hydraulics. Will the upsurge of electrical vehicles sound a death knell for hydraulics?
Mobile applications of fluid power are widespread. Nearly every self-propelled wheeled vehicle has either hydraulically-operated or pneumatically-operated brakes. Earthmoving equipment such as bulldozers, backhoes and others use powerful hydraulic systems for digging and also for propulsion.
Mobile equipment used in the construction, mining and agriculture industries represents the largest sector of fluid power technology. Hydraulics has been used in virtually all heavy equipment for roughly 75 odd years, attributable to the tremendous forces and torques the technology can generate while also offering simple, versatile control.
More recently, the incorporation of electronic sensors and controls adds a degree of automation to the equipment that boosts machine productivity and efficiency, while reducing the skill level and experience required to operate machines safely.
Over the past few years, there have been advances in technology that improve hydraulic performance and efficiency by controlling hydraulic pump output electronically, rather than with pressure-based control. Functions such as load sensing, power limiting, and flow sharing can now be monitored and controlled to match the output of the pump to the ever-changing load demand of the machine. This reduces fuel consumption and emissions of the device while also improving productivity and performance.
Considering various developments in the field of hydraulic technology and the nature of demanding application, for the off-highway vehicle segment, hydraulics can never be completely replaced on mobile machinery at least in the next 10 years for sure. This is because there is simply no efficient, compact and reliable way for electric linear actuators to match hydraulic cylinders. Electronic controls and integration will continue to happen in the mobile hydraulic segment which will improve efficiency and performance.
What are the new trends that hold promise for hydraulics and pneumatics in the digital era? How relevant is fluid power in process industries today?
There have been rapid advancements in fluid power technology over the past two decades on account of many factors, viz., Safety Standards & Compliance, Manufacturing Efficiency, Operational Efficiency and the Concept of Industry 4.0 and Industrial Internet of Things (IIoT).
As a result, manufacturers of fluid power equipment have worked on all of these factors to make their equipment in tune with these requirements, using advancements in the material technology and manufacturing – metal cutting technology, including 3D printing, and integration with electronics to make them smart and sleek. The technology trends which drove the developments in fluid power segment include smaller valve/pump sizes for the same or better flow capacities, with embedded controllers, lower electrical power and higher electrical efficiency.
The fusion of the physical world of production with the virtual world of information technology into Industry 4.0 is becoming increasingly important. The specific requirements placed on automation technology are decentralised intelligence and autonomous behaviour, open communication standards and rapid networkability for exchange of data in real time.
To address the needs of IIoT and Industry 4.0, hydraulic manufacturers of repute have systematically expanded their portfolio of electro-hydraulic components and modules with digital interfaces and sensor intelligence. The products have a decentralised intelligence and exchange data via multi-Ethernet interfaces with other devices like controls. Standardised, integrated digital electronics offers a wide range of functionality driven by software applications.
Hydraulic components are adapting more and more to electronics for intelligent motion as well as to sensors for gathering operating data values online. Analysis of this data is the key concept for condition monitoring, predictive maintenance, and machine-to-machine communication. Thus in fluid power equipment, Sensor Technology and Ethernet Connectivity is definitely leading the way for implementation of ‘Smart Manufacturing’ and ‘Industry 4.0’.
Are hydraulic and pneumatic devices compatible and in step with digital technologies and integrate with IIoT seamlessly?
With the emergence of the Industrial Internet of Things (IIoT) and Industry 4.0 started the extensive use of sensors throughout automation systems, including pneumatic and hydraulic components. Sensors have become smaller, more lightweight, and easier to use in various fluid power components, allowing measurement of temperatures, pressures, flow rates, cycle times, valve response rates and so on. Even the simplest devices can provide crucial information at some point.
Traditionally, pneumatic solenoid operated valves were powered by simple contactors in an output card. Today, more of them are on the network and have built in diagnostic sensing to monitor temperature, voltage, current and even cycle counts. Development of pneumatic valve terminals incorporating serial communication paved the way for integration of sensor technology into the valve islands. This has made the pneumatic systems more efficient and adaptive.
A smart pneumatics monitor module, from one of the reputed pneumatic manufacturers provides users with reliable information on the state of wear of pneumatic actuators, valves and other devices, as well as the energy efficiency of pneumatic systems, which helps in ‘Predictive Maintenance’.
With modern day sensors which are compatible with Bluetooth, machines can send update messages via text or contact specific service people when systems fail.
A hydraulic manufacturer has developed a smart phone app which is able to wirelessly configure the hydraulic valves in an installation using Bluetooth connectivity.
With all these developments and newer applications of fluid power in almost all the industry segments, we can safely say that fluid power systems are here to stay at least for a decade, if not more.
Shashank Gune is an industry veteran in pneumatics, with more than 25 years of rich experience in the fluid power domain. He has held key positions in fluid power multinational companies like Parker Hannifin, Schrader Duncan and Nucon Industries. He has been conducting training programmes for the industry on Pneumatics. He started his own venture, Techtonic Engineering, to offer techno-commercially optimised fluid-power solutions.
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