Five Typical Applications of Hydraulics

The use of fluid power is widespread in many stationary and mobile applications. Many of the operators, technicians, and engineers are not well-versed of the operational, maintenance, and safety aspects of fluid power. Therefore, a systematic training is essential for them to handle fluid power systems. Fluidsys training Centre, Bangalore is well equipped to provide basic as well as advanced level courses in the field of pneumatics and hydraulics. The training centre is also happy to provide information on fluid power in a simple and interesting manner. Hope this will benefit especially the new entrants in the field of fluid power.

Hydraulic Application

Courtesy: Bosch Rexroth Corporation, USA

The expansion of hydraulic applications has evolved over a period, beginning with the development of the hydraulic press by Joseph Bramah in 1795. Hydraulic systems were developed in the twentieth century to control ships and aircraft systems. Military vehicles and other applications such as radar positioners, missile launchers, etc preferred hydraulics. Because of their early success, the list grew to include industrial, construction, agriculture, forestry, mining, and marine equipment. CNC lathes, turning centres, machine tools, presses, and injection moulding machines also make use of the muscle power of hydraulics. The modern hydraulic technology can be used to make the brakes in cars work, help airplanes to climb and turn, and steer and stabilize giant ocean liners. Hydraulic applications have sprung up in a wide variety of areas in the last few decades. Today we can see many examples of hydraulic technology in use all around us. Some of the typical hydraulic applications are highlighted below:

1. Hydraulic Press

Press

Courtesy: Bosch Rexroth Corporation, USA

The primary function of a hydraulic press is to convey force and/or motion to its tool and die section for forming or blanking workpieces. The press uses a hydraulic pump and a large-volume cylinder for the power transmission and work operations. It is controlled by fast-acting valves for superior performance. It also incorporates interlocking and barrier guards for safeguarding the equipment and personnel. Modern presses are capable of configuring work parameters such as the travel distance and the amount of force.

2. Hydraulic Work Holding Systems

Hydraulic work-holding systems are used to perform the positioning and clamping functions of work-pieces. They are suitable for applications ranging from the simplest fixture to more complex robot-assisted machining centers. Linear cylinders, clamping cylinders, and support cylinders are employed in hydraulic workholding systems for the positioning and precise support of workpieces. Hydraulic clamping is less time-consuming than mechanical clamping. The use of hydraulic workholding system reduces the cycle time thereby increasing the manufacturing capacity and reducing the costs. It is preferable in high-volume applications, or when critical tolerances need to be held. However, it is costlier than a comparable mechanical clamping system. 

3. Plastic Injection Moulding Machine

A plastic injection moulding machine has an injection section and a mould section. The injection section consists of a barrel, a screw, a heater, a nozzle, and hydraulic actuators for plasticizing solid raw plastic and injecting. The mould section performs the clamping and moulding operations. The machine operates on a four-step cycle: (1) plasticizing solid raw plastic, (2) closing mould and clamping, (3) injecting the plastic, and (4) opening the mould.

Plastic Injection Moulding Machine

Courtesy: Bosch Rexroth Corporation, USA

A screw rotating inside the barrel shears and heats the granular raw plastic and softens it to the plastic (gently flowing) state. This operation is, usually, done with a low-speed high-torque (LSHT) hydraulic motor. The clamping arrangement for the mould has moving and fixed platens. These platens hold the mould tool together under pressure. The gently flowing plastic is then injected into the mould under pressure. Hydraulic cylinders are used for clamping the mould and injection of the plastic material into the mould.

4. Hydraulic Excavator

It is a piece of heavy construction equipment operating similar to a combined human arm and hand. It is used to dig and move large objects. It consists of three parts: (1) a set of working elements, (2) an upper structure, and (3) a lower structure.

Excavator1

The working part consists of a boom, an arm, and a bucket, which are powered by hydraulic cylinders. The boom provides the up and down movements of the arm. The powerful arm with the bucket attachment is designed for digging, lifting, and loading soil. The bucket with hardened side cutters and teeth are used to dig or break hard soil and rocks.

The hydraulic system in the excavator typically consists of three pumps that are driven by its engine. The third pump supplies fluid to its pilot control circuits at low pressures ranging up to 50 bar [700 psi]. Joysticks are provided to control the bucket and boom assembly movement and the upper structure rotation. A boom suspension circuit for the wheeled excavator can be incorporated to smooth out the bounce of the loaded bucket during its transport through rugged terrains. Many of the control solutions for the excavator can easily be achieved through the use of cartridge valves and manifolds.

The use of hydraulic technology for the operation of an excavator provides faster cycle times, reduced noise, ease of operation, high overall efficiency, and greater accuracy and precision. The power rating typically ranges from 10-3300 kW [13-4500 hp]. It is specified by its maximum digging reach and digging depth, minimum swing radius, etc.

5. Drill Rigs

A rig is a machine used to drill wells and it provides a means for discovering hidden energy reserves. It consists of a drilling system, a feed system, and a propulsion system. The rig is mounted on an undercarriage. The drilling system makes holes for oil or mineral exploration. The feed unit moves the drill unit up and down. A propulsion system runs the undercarriage. The required movements of drill unit, feed unit, and propulsion system are hydraulically actuated and controlled.

Rig


Reference: Industrial Hydraulic Systems-Theory and Practice, Joji Parambath, Universal Publishers, Boca Raton, U S A, 2016.

[ http://www.universal-publishers.com/book.php?method=ISBN&book=1627340580 ]


Authored by JOJI Parambath, Founder/Director, Fluidsys Training Centre, Bangalore, email: info@fluidsys.in, web++: https://fluidsys.org


 

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