MECHANICAL ENGINEERING

(1) Shaper is used for small job  whileplaner  work with large size of work piece. (2) Tool is the moving part in shaper machine while  Work piece is the moving part in planer. (3) Work piece remain stationary on this machine in shaper while t ool remains stationary in planer. (4)shaper is light duty machine while planner is heavy duty. (5)Shaper  uses single point cutting tool while planner uses multipoint cutting tool. (6)Shaper uses quick return mechanism while planner is driven by gear or hydraulic arrangement. (7)shaper has poor accuracy while planer has high accuracy.

Brake fluid is a type of hydraulic fluid used in hydraulic brake and hydraulic clutch applications in automobiles, motorcycles, light trucks, and some bicycles. It is used to transfer force into pressure, and to amplify braking force. It works because liquids are not appreciably compressible.                            CHARACTERISTICS OF BRAKE FLUID (1)Low Compressibility: Brake liquids must maintain low level of compressibility when temperatures and pressure changes. (2)HIgh boiling point:Boiling point should be high so that it doesn't boil during it's operation (3)Low freezing point:For dependable, predictable stopping mechanism operation, brake liquid must keep up a consistent thickness under an extensive variety of temperatures, including compelling chilly. (4)Anti corosion:Additives are added to make it corosion resistant.               TYPES OF BRAKE FLUID COMMONLY AVAILABLE 1)DOT 3 2)DOT 4 3)DOT 5 DOT 3 and DOT 4 are glycol based

NEED OF SUSPENSION IN TRACTOR Tractors other heavy commercial vehicles do not have suspension because of the following reasons: (1)While moving tractor is supposed to maintain a constant height for ploughing and digging.If there is a suspension system then it will oscillate in the direction of suspension.Thus it will be unable to maintain a constant depth. (2)Due to Suspension offroad stability is less. (3)While ploughing  there will be load trying to make the tractor stop as its inserted in the ground. This may cause the body of the tractor to tilt backwards   Note:   As the speed of the tractor is less and the tyres big(which absorbs more shocks),the need of suspension is felt less. 

Working fluid of refrigrator is refrigrant.Refrigerant is a compound typically found in either a fluid or gaseous state. It readily absorbs heat from the environment and can provide refrigeration or air conditioning when combined with other components such as compressors and evaporators.                        Refrigration process consists of four process as follows: 1)Compression:process 1-2 is compression.It is adiabatic process.compression is either dry compression or wet cimpression depending on wether saturated vapour or wet vapour being compressed.Dry compression is preferred. 2)Cooling:2-3 is cooling process.After compression temperature increases.So cooloing is needed.It is isobaric process. 3)Expansion:3-4 is expansion process.It is isentropic process.It is irreversible.Throttling cause sudden pressur drop.Due to pressure drop boiling point of refrigrant decreases and it starts evaporating,heat required comes from refrigrant.So its temperature drops.

PELTON TURBINE :The pelton wheel turbine is impulse turbine,which is of tangential flow type. In this turbine energy at the inlet of turbine is in the form of kinetic energy.This is used for low flow rate and high head.Pressure through out remains atmospheric. The main parts of pelton turbine are: 1)Nozzle or flow controlling:It controls the rate of flow as per requirement of variable power. 2)Runner or bucket:It is of shape double hemispherical seperated by splitter which devides water without shock. 3)Casing:Casing has not hydraulic function.It only prevent water from splashing. 4)Braking jet:To stop the runner in smallest possible time.                                                       Fig:Pelton wheel turbine runner FRANCIS TURBINE :Francis turbine is reaction turbine.In this type of turbine at inlet is in the form of both kinetic as well as pressure energy.The runner is completely enclosed that is it is air tight.As the water flows a part of pres

                                   PISTON It is a cylindrical component which reciprocates inside engine cylinder.It is movable wall.It transmits power produce to crankshaft through connecting rod.It provide seal for the gasses. Material : For piston desired properties are: a)Uniform expansion at high temperature b)Low weight so aluminium alloy is best choice                                                                       PISTON RING            On piston there are gooves which hold piston rings.This include compression ring or gas ring,wiper ring and oil ring.There prime function is to seal the gas and circulate lubricating oil. compression ring or gas ring :it is located closest to piston hesd.It’s function is to seal the gasses during high pressure.When  the gas is burnt huge pressure is generated.Which can leak to casing. Wiper ring: It is piston ring with tapered face.It is used to further seal the combustion gass.It wipes out cylinder wall to remove exc