Steam Engine , the world's first engines ever invented . This one machine is the genesis of a family tree of modern technology : Airplanes , Power Plants , 
Cars and even Refrigerators they all are their invention to this innovation  , a couple hundred years age engineers developed the technology to extract energy from FIRE  and use that energy with WATER and STEAM to move this huge machine: : Airplanes , Power Plants , Cars  and many more  . 
The THOMAS NEWCOMEN Steam Engine  
  
Steam engine is a machine that converts the heat energy of steam into Mechanical energy , steam passes into cylinder due to which a piston move  back and forth ,with this piston movement that the engine can do Mechanical Work 

Main Parts of steam engine : steam chest , slide valve , piston assembly , cylinder ,  Flywheel , Stevenson's Link 
Inputs : Water , Steam , High Temperature , High Pressure , Less Volume , 

Steam Engine Works :  

         water is boiled in boiler sealed tank in high pressure .The steamed  builds up and trapped ,and  the only way Steam to escape is by travelling through a slide valve ,a cylinder move piston down and slide valve up and then exhaust  where piston is up in initial stage  at  as the high pressure steam follows this path as slide valve is up then steam follows down valve this path it hits the piston up to move which in turns moves the piston rod , the movement of the piston rod transfer to the flywheel causing it to rotates the wheels of the tractor or whatever Farm machinery may be attached 
but how this steam makes to push metal , this  is only with the help of High temperature , less volume which helps to generate high pressure , pressure = Force/AREA  , Now we still have high pressure on bottom side of piston , but piston has reached the end of stoke so it can't move any further , so ,the slide valve moves down and  path is open for the steam vent through exhaust  into open air ,When the slide valve moves over it also blocks the steam from applying pressure to the piston from up at the same time it open a path for the boiler allowing it to push on the down side of the piston now the piston is pushed in the down side and once it reaches the end of its stroke , or movement  ,the slide valve shifts up over thus completing one full cycle 
            Because steam is pushing on the piston in one direction and then the other , up and down is venting through the exhaust , it is called double acting cylinder 
and cycle repeats , cycle used to analyze this process is called the Rankine cycle.

         Slide valve is driven by two eccentrics down there on the crankshaft
one eccentric and rod drives the engine in a forward direction and other one drives the engine in a reverse direction

         STEVENSON'S LINK the two rods are link together  with the piece of metal ,allows a smooth transition in a forward to reverse it also has the benefit of being able to adjust the stroke of the valve and thereby improve the efficiency of the engine 
the movement of Stevenson's link is achieved by pushing on handle due to that valve transferring from up to down

Edu ​​​​​​​POTY 2021 ​​​​​​​POTY 2021-Project ​​​​​​​