BASIC HYDRAULICS (LECTURE NOTES SERIES FOR DR. REDDY Labs BADDI) Er. Anoop Aggarwal (Associate Professor, Deptt. Of Mechanical Engineering) CHITKARA UNIVERSITY Er. GAUTAM MALIK
Fluid Power Machine
Hydraulic Systems Fluid power systems that use oil or another liquid.
How does a fluid power system work? Fluid power systems work by force being applied to a fluid (gas or liquid), then the energy of the fluid, under pressure, transfers its energy to a mechanically device to perform work.
Pressure The amount of force distributed over a unit of area, usually expressed in pounds per square inch. Pressure = Force (F) Area (A)
PASCAL LAW When a force is applied to a confined fluid, the increase in pressure is transmitted equally to all parts of the fluid.
Pascal s Principle Force All have equal pressure
Transmitting Pressure in a Fluid When force is applied to a confined fluid, the change in pressure is transmitted equally to all parts of the fluid.
Pascal Law 9
A closed hydraulic system such as the one diagrammed here provides a mechanical advantage similar to that of a simple lever. In a closed fluid system a small force exerted on a small cylinder could balance a large force on a large cylinder. For example, 1 pound of force applied to a 1 square inch cylinder can balance 100 pounds of force on a 100 square inch cylinder. This is how we can move a 100 pound we ight using only 1 pound of force. The distance the 100 pounds will travel is inversely proportional to the distance the applied force travels. That means if we move a 1 square inch cylinder a distance of one inch, we only move the 100 square inch cylinder 1/100th of an inch
4N 3. What is the total force of the right Piston? F=Pa= 2000N/m2 x 20m2 = 40,000N 20m2.002m2 1. What is the pressure of the left piston?p= F/a = 4/.002 = 2000Pa 2. What is the pressure of the right Piston? 2000Pa
Hydraulic Brake The hydraulic brake system of a car multiplies the force exerted on the brake pedal.
Hydraulic System Er. GAUTAM MALIK
Components Hydraulic pump or air compressor, which converts mechanical power to fluid power. Cylinder or motor, which converts fluid power to linear or rotary mechanical power. Valves, which control the direction, pressure and rate of flow. Filters, regulators and lubricators, which condition the fluid. Manifolds, hose, tube, fittings, couplings, etc., which conduct the fluid between components. Sealing devices, which help contain the fluid. Accumulators and reservoirs, which store the fluid. Instruments such as pressure switches, gauges, flow meters, sensors and transducers, which are used to help monitor the performance of a fluid power system.
Fluid power applications Mobile: Here fluid power is used to transport, excavate and lift materials as well as control or power mobile equipment. End use industries include construction, agriculture, marine and the military. Applications include backhoes, graders, tractors, truck brakes and suspensions, spreaders and highway maintenance vehicles. Industrial: Here fluid power is used to provide power transmission and motion control for the machines of industry. End use industries range from plastics working to paper production. Applications include metalworking equipment, controllers, automated manipulators, material handling and assembly equipment. Aerospace: Fluid power is used for both commercial and military aircraft, spacecraft and related support equipment. Applications include landing gear, brakes, flight controls, motor controls and cargo loading equipment.
Applications
Applications
Applications
Pump types
External gear pump Hydraulic and Pneumatic Systems 21
Pump types Off-centered internal gear pump Hydraulic and Pneumatic Systems 22
Pump types Centered internal gear pump / gerotor pump Hydraulic and Pneumatic Systems 23
Pump types Screw pump Hydraulic and Pneumatic Systems 24
Pump types Vane pump Hydraulic and Pneumatic Systems 25
Pump types Axial piston pump with tilting block Hydraulic and Pneumatic Systems 26
Pump types Axial piston pump with tilting cam plate Hydraulic and Pneumatic Systems 27
Radial piston pump Hydraulic and Pneumatic Systems 28
Functions of Fluid Primary function is to create force and motion as flow is converted to pressure near the point of use. Second by occupying the space between metal surfaces, the fluid forms a seal, which provides a pressure barrier and helps exclude contaminants. A third function often misunderstood is lubrication of metal surfaces. The fourth and final function provided by hydraulic fluid is cooling of system components.
Types of Hydraulic Oil There are many types of hydraulic fluids, of which the most common would be mineral oil, polyaphaolefin and organophosphate ester. Others are based on glycol esters and ethers, vegetable oil,castor oil, or silicone. Certain hydraulic fluids are produced from crude oil and others are manufactured by many companies.
Cylinders
Single Acting & Double Acting Cylinder
Telescopic Cylinder
Hydraulic Gear Motor
Basic Hydraulic Circuit
Pressure Sequence Circuit
Regeneration circuit Regenerative Circuit. Regenerative circuits are used when it is desirable to rapidly advance an actuator into position to reduce cycle time. When configured as a regenerative system, cylinders can be advanced more rapidly than in normal operation with the pump flow rate alone. In order to accomplish regeneration, the fluid leaving the rod end of the cylinder is routed back to the cap side of the cylinder to combine with the pump flow rate from the pump Er. GAUTAM MALIK
Types of Maintenance Maintenance may be classified into four categories: (some authors prefer three categories- scheduled and preventive maintenances are merged) 1. 2. 3. 4. Corrective or Breakdown maintenance Scheduled maintenance Preventive maintenance Predictive (Condition-based) maintenance
Purpose Attempt to maximize performance of production equipment efficiently and regularly Prevent breakdown or failures Minimize production loss from failures Increase reliability of the operating systems
Safety