Fluid Power The Oldest Form of Power Transmission
Published on : Saturday 06-03-2021
Fluid power-based machinery offers greater reliability and consistency of operations, says Darshana Thakkar.
A fluid power transmission system is the most efficient and cost-effective method of power transmission. An average industry professional knows about the Hydraulic and Pneumatic systems. Here I love to share the basics and benefits of the same for the non-engineering professionals of the industry.
Before 1700, the industry was run predominantly by human and animal power; farmers in the field and animals assisting them with the daily rigours of work. From nature wind and water is available as the source of energy. Later on, water became one of the most important power sources and thus the driving force behind the industrial revolution.
Water power industrial revolution
Water was used in conjunction with the Water Frame invention by Richard Arkwright to power the whole production cycle in large factories. Giant water wheels would sit next to the factory and drive production through the flowing water over the machine. The water would be powered downstream in a river to turn the machinery.
Water power was having many limitations like weather conditions, a factory next to a river, level of rainfall, drought in the summer, or ice in the winter. These limitations are overcome with the evolution of steam power.
Steam power industrial revolution
Boiling water was used to create a mechanical motion and was the driving force behind several inventions including the steam engine locomotive. The benefits of the steam process over the water were that it didn’t vary by season like water power. It could also be located anywhere meaning factories didn’t need to be close to a water source.
Steam engines are a great example of how industrialisation led to changes across all areas.
Richard Arkwright is the first to use Watt’s steam engine to power textile machinery. By 1775 Arkwright developed mills in which the whole process of yarn manufacture is carried on by one machine.
In 1879 with the invention of the Light Bulb by Thomas Edison, the next phase of the industrial revolution started and as such apart from fluid and mechanical power transmission, the new age of electrical power transmission started. Long-distance transmission of power became possible with the invention of electricity.
As such to run any machine or to produce any products some kind of energy is required. The following 4 types of power transmission methods were available:
1) Mechanical
2) Electrical
3) Hydraulic, and
4) Pneumatic.
The Power Transmission method is an engineering method that matches the power required by the machine and the working parts of the machine in terms of energy configuration, movement speed, and motion form.
There are several advantages and disadvantages of each power transmission method over others.
I believe this background is enough to understand more about the basics of a fluid power system.
The fluid power system is divided into two parts.
1) Hydraulic system: This method uses liquid (oil or water) as a working medium to transfer the energy and control the operation.
2) Pneumatic System: This method uses compressed gas or air as a working medium to transfer energy and control the pressure of the gas.
Advantages of fluid power
Hydraulic and pneumatic systems share many benefits for the machines in which they are installed. These include:
i. High horsepower-to-weight ratio: You could probably hold a 5-hp hydraulic motor in the palm of your hand, but a 5-hp electric motor might weigh 18 kg or more.
ii. Safety in hazardous environments: Because they are inherently spark-free and can tolerate high temperatures.
iii. Force or torque can be held constant: This is unique to fluid power transmission.
iv. High torque at low speed: Unlike electric motors, pneumatic and hydraulic motors can produce high torque while operating at low rotational speeds. Some fluid power motors can even maintain torque at zero speed without overheating.
v. Energy and cost efficient: pressurised fluids can be transmitted over long distances and through complex machine configurations with only a small loss in power.
vi. Multi-functional control: a single hydraulic pump or air compressor can provide power to many cylinders, motors, or other actuators.
vii. Simple construction: elimination of complicated mechanical trains of gears, chains, belts, cams, and linkages
viii. Quick operations: motion can be almost instantly reversed.
Hydraulic and pneumatic systems are both widely used in stationary (industrial) and off-highway (mobile) equipment. Hydraulic systems are widely used when heavy force or torque is involved, such as lifting loads weighing several tons, crushing or pressing strong materials like rock and solid metal, and digging, lifting, and moving large amounts of earth.
Although pneumatics is capable of transmitting high force and torque, it is more widely used for fast-moving, repetitive applications, such as pick-and-place operations, gripping, and repetitive gripping or stamping.
Of course, in both cases, electronic controls and sensors have been implemented into fluid power systems for the last few decades. These electronics make hydraulic and pneumatic systems faster, more precise and efficient, more reliable, and allow them to be tied into statistical process control and other factory and mobile equipment control networks.
Major components of fluid power system
Fluid power systems consist of multiple components that work together or in sequence to perform some action or work.
The major components of any fluid power system include:
a. A pumping device: A hydraulic pump or air compressor to provide fluid power to the system.
b. Fluid conductors: Tubing, hoses, fittings, manifolds, and other components that distribute pressurised fluid throughout the system.
c. Valves: Devices that control fluid flow, pressure, starting, stopping, and direction.
d. Actuators: Cylinders, motors, rotary actuators, grippers, vacuum cups, and other components that perform the end function of the fluid power system.
e. Support components: Filters, heat exchangers, manifolds, hydraulic reservoirs, pneumatic mufflers, and other components that enable the fluid power system to operate more effectively.
Electronic sensors and switches are incorporated into fluid power systems to provide electronic controls to monitor the operation of components. Diagnostic instruments are also used for measuring pressure, temperature, and flow in assessing the condition of the system and for troubleshooting.
Hydraulic applications
Off-highway equipment is probably the most common application of hydraulics. Whether it is construction, mining, agriculture, waste reduction or utility equipment, hydraulics provide the power and control to tackle the task. Hydraulics is also used in heavy industrial equipment in factories, marine and offshore equipment for lifting, bending, pressing, cutting, forming and moving heavy workpieces. Examples: agriculture machinery; construction machinery; entertainment parks; marine & offshore; waste & recycling; energy; machine tools; metal forming; military & aerospace; mining; and utility equipment.
Pneumatic applications
Factory automation is the largest sector for pneumatics technology, which is widely used for manipulating products in manufacturing, processing, and packaging operations. Pneumatics is also widely used in medical and food processing equipment and chemical plants and refineries to actuate large valves. It’s used on mobile equipment for transmitting power where hydraulics or electromechanical drives are less practical or not as convenient pneumatics is typically a pick-and-place technology, to perform the repetitive operation thousands of times per day.
Vacuum is used for lifting and moving workpieces and products. Combining multiple vacuum cups into a single assembly allows lifting large and heavy objects. Major sectors include: food & beverages – ensures reliability and helps to move hard to handle foods; entertainment & amusement parks; factory automation; material handling; medical equipment; off- and on-highway vehicle systems; packaging industries, etc.
How can MSME industries leverage the benefits of fluid power technology?
Machinery manufacturers
In our country, a large number of MSME industries are involved in the manufacturing of machinery from basic to fully automatic. With increasing global competition in terms of technology, machine cost, operating cost size, and delivery period of the machines, MSME entrepreneurs need to enhance the business performance with the adoption of the latest trends in the industry.
1. By replacing the electrical motor with a hydraulic system and/or mechanical transmission with the hydraulic or pneumatic system the overall cost can be reduced.
2. Assembly is simpler and has fewer moving mechanical parts which helps to reduce manufacturing time and reduce labour cost as well.
3. The size of the machine becomes compact as such requires less space during manufacturing, in a warehouse and also requires less space at the customer site.
4. By eliminating moving parts like gears, belt drives, chain blocks, etc., the operating cost and breakdown cost for a customer site is reduced.
5. The reduced maintenance cost of the overall system for the customer helps to become competitive in the market.
For machinery buyers
With my vast experience in the machine manufacturing industry, I recommend machinery buyers to choose machines with a fluid power operating system instead of electro-mechanical power. It may be possible that the initial cost of hydraulic or pneumatic system base machinery is higher. But be assured that in the long run in terms of operating and maintenance costs, it will be cheaper than the electro-mechanical counterpart. Not only this, reliability and consistency of operations are also higher in fluid power-based machinery.
Darshana Thakkar is MSME Transformation Specialist and Founder, Transformation – The Strategy Hub. An Electrical Engineer followed by MBA – Operations with rich industry experience, Darshana is an expert in transformation, cost reduction, and utilisation of resources. She has invested 25 years in transforming Micro and Small Enterprises. Her rich experience in resolving pain areas and real-life problems of SMEs helps organisations achieve quick results. Her expertise in managing business operations with limited resources helps clients transform their business practices from person driven to system driven with existing resources.
Darshana has helped many organisations to increase profitability and achieve sustainable growth. She is passionate to support the start-up ecosystem of our country. She is associated with CED, Government of Gujarat as a Business Function Expert in the Entrepreneurship Development program, as faculty for industrial subjects in the Second Generation Program (SGP), and as a start-up mentor and member of the start-up selection committee in the CED incubation centre.
