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Methods of Inspection in Casting

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In casting process, first few castings will be inspected dimensionally and the pattern is qualified afterwards, only few random inspection will be done. Every casting must be inspected for finding out the defects in casting process. Different methods of inspection for finding out defects  in casting process are discussed below 1.      Visual Inspection 2.      Hydrostatic Pressure Test 3.      Magnetic Particle Inspection 4.      Radiographic Examination 5.      Ultrasonic inspection 6.      Dye Penetrant Inspection 7.      Coin Testing 1. Visual Inspection Common defects such as surface roughness, obvious shifts, omission of cores and surface cracks can be detected by a visual inspection of the casting. Cracks may also be detected by hitting the casting with a mallet and listening to the quality of the tone produced. 2. Hydrostatic Pressure Test §  The Hydrostatic pressure test is conducted on a casting to be used as a pressure vessel. §  In this test, first all the flange
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Governor Types – Centrifugal Governor and Inertia Governor

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Governor is a device used to maintain the speed of an engine within specified limits when the engine works in varying of different loads. Based on the source of controlling force, the governors can be classified into two types. Governor types are centrifugal governors and inertia governors. Centrifugal Governors : In centrifugal governors, multiple masses know as governor balls, are responsible to revolve about the axis of a shaft, which is driven through suitable gearing from the engine crankshaft. Each ball is acted upon by a force which acts in the radially inward direction and is provided by dead weight, a spring or a combination of two. This force is commonly called as the controlling force and it will increase as the distance of the ball from the axis of rotation increases. The inward or outward movement of the ball is transmitted by the governor mechanism to the valve which controls the amount of energy supplied to the engine.                             Inertia  Gov
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Types of Internal Combustion Engines:

Internal combustion engines can be classified into a large number of types based on several criteria. The classification of IC engines is given below: 1.      Based on the fuel used ·         Diesel Engine ·         Petrol Engine (or Gasoline Engine)   2.      Based on the type of cycle ·         Otto Cycle Engine ·         Diesel Cycle Engine ·         Dual Cycle Engine   3.      Based on the number of strokes per cycle ·         Two-stroke Engine ·         Four-stroke Engine   4.      Based on the number of cylinders ·         Single Cylinder Engine ·         Multi cylinder Engine Ø  Twin Cylinder Engine Ø  Three Cylinder Engine Ø  Four Cylinder Engine Ø  Six Cylinder Engine Ø  Eight Cylinder Engine Ø  Twelve Cylinder Engine Ø  Sixteen Cylinder Engine   5.      Based on the type of ignition ·         Spark Ignition Engine (S.I. Engine) ·         Compression Ignition Engine (C.I. Engine)   6.      Based on the lubrication system used ·         Dry sump lubricated engine ·         Wet
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Air-cooling System in Reciprocating Engine

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In an air-cooling system, the outer surface of the cylinder and cylindrical head in reciprocating engine is cooled by air flowing over them. To increase the heat transfer rate from the surface, the metallic fins are cast on the cylinder and cylinder head. These fins increases the heat transfer area and thereby heat transfer rate. Air cooling system is a very simple, reliable and maintenance-free cooling system, with no operating cost. It is very suitable for small engines of automobiles.   Applications of Air-cooling System: 1.      Air-cooling system is used in small engines, i.e., motor cycles, scooters, mopeds, airplanes and combat tanks, where speed of the vehicle gives a good velocity to the air to cool the engine. 2.      It is also used in small stationary engines used for agriculture and industries. Advantages of Air-cooling System: §  The design of the engine becomes simpler with use of  an air-cooling system. §  There is no cooling pipe radiator, fan pump and liqu
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Types of Loads

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Different types of loads  in engineering mechanics are compression, tension, torsion and bending. Compression : Compression loading is an effect in which the component reduces it size. During compression load there is reduction in volume and increase in density of a component. Tension: Tension is the act of stretching rod, bar, spring, wire, cable etc. that is being pulled from the either ends. Torsion: Torsion is the act of twisting of an rod, wire, spring etc. about an axis due to applied couple (torque). Bending: Bending is act of changing component from straight form into a curved or angular form.  
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Types of Mechanical Forces

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A force exerted on a body can cause a change in either the shape or the motion of the body. The unit of force in SI system is the  newton  (N) and CGS system is  dyne . No solid body is perfectly rigid and when forces are applied to it, changes in dimensions occur. Such changes are not always perceptible to the human eye since they are negligible. For example, the span of a bridge will sag under the weight of a vehicle and a spanner will bend slightly when tightening a nut. It is important for civil engineers and designers to appreciate the effects of forces on materials, together with their mechanical properties of materials. There are three main types of mechanical forces that can act on a body. They are:                                                                  1.      Tensile force 2.      Compressive force and 3.      Shear force   1. Tensile force Tensile force that tends to stretch a material, as shown in the figure 1 below. Figure 1: Tensile force
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Super chargers

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Super charger acts as an air compressor. It is used to increase the density and pressure of the air that is supplied to the internal combustion engine. In the engine, during the intake of the cycle it takes more oxygen and burn more fuel to accomplish the work. This is due the power increase. By using the belts, gears, shafts, chains all of these are connected to the engines crank shaft to produce super charge. We can see two types of the super chargers. To that matter after super charging, the air enters into the engine. After compression the pressure in the air is compressed and it super charges the system by 1.5 to 2 times to increase the entry of the pressure. In one type of the super charger the engine shaft is mechanically linked to the shaft. The shaft energy must turn into useful work input for the super charger. In another type of the super charger the compressor is attached to the turbine. Exhaust gas must be allowed to enter into the turbine. The turbine drives the super cha
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