Vapour Absorption Refrigeration

 Even though confusing by its name an Absorption Refrigerator is one which uses a heat source to drive its cooling unit.. sounds crazy enh?,.. a refigerator tht uses heat to cool things .. well thts the way it works...

  One of the most commonly use Absorption Refrigeration system is the one usein Ammonia , water and Hydrogen mixture.......   at normal atmospheric pressure ammonia is a gas  which liquidifies at a temp of -33°C... in this system ammonia is pressurized to its liquid form an is mixed with water and a very small amount of Hydrogen... Ammonia acts as REFRIGERANT and Hydrogen being light in weight act as TRANSPORTING agent which takes up the vapour .

The mixture will be present in the bottom most chamber. the external heat source liberates ammonia from the solution and an hydrogen takes this vapours of ammonia up to the condenser , where ammonia condenses into liquid form( Condeser is the FINNED part tht we ususally get to see behind the refrigerators) . This liquid  ammonia now enters the evaporating chamber ( in form of Pipes lining the area to be cooled). there the heat from the freezer is absorbed by the ammonia to evaporate in to gaseous form, thus cooling our required area. this vapour along with the hydrogen enters the bottom tank again, where it is mixed with water again to form strong solution and the Cycle goes on .

  This kind of refrigeration systems are usually used where electricity is not continuously available. A a solar heat absorbing device can be coupled to this system as a heat source, which would be very efficient . ONE such system was made by me and my friends for our final semester projects ( B.TechMechanical).

Escalator

  Escalator is a device , a moving staircase used to transport normally people from one floor of building to another. Most us would have definitly used a elevator at some point of time ...Might be at airport, metro station or at a shopping mall... Though it reduces our effort to get up there , have u ever wondered how doe sit work..... Escalators are nothin much but an advanced for of a conveyor belt....

 

                                                                                                                                     

Taking a look at the parts and working of an elevator:

1. Landing platforms
2. Truss 
3. Tracks
4. Steps
5. Handrails

        The Landing Platforms house the the gear systems, motor drive , idler sprocket(  free rotating gear acting as support) ,the curved section of the track etc.. It has pltes that merges with the floor , that helps the passengers to stand before stepping foot on the steps.. in the recent models , these plates have sensors which automatically switched ON & OFF the escalator according to the presence of a user . this system usually works on weight sensing switches which operates with weight of the passenger standing on these plates ..

     The Truss is the frame work provided at the sides of the escaltor which bridges between the upper nd the lower landing gears. It imparts strength to the whole sturcture, usully made of steel. it will have aluminum sheet covering on the outer sides.

   The track system is usually built between  the truss to guide the step chain.It continuously pulls the steps from the bottom platform and back to the top in an endless loop.

   Step are usually made by the process of die casting of aluminium or steel.They are joined end to end using hinges which allow them to form a loop , like a chain.. the track systems are attached to step chain as well.. the rotating power drive motor moves the track system which in turn moves the the step chain....

   

The Handrail is also a vital part of the escalator system which provides suppport to the passengers. this is also a loop of flexible strong fibre like material which moves wid the  same speed as that of the escaltor 

  Even though many claim patents on various escalators designs being used today , Nathan Ames is considered to be the inventor of this wonderful machine.....

                                                                                    

                                           COURTESY: WIKIPEDIA

Where it all started....

Today , the engineering world is very vast . And it might take years for one to explore , understand and accept the things that he might discover out there. As this is Mechanical Engineering Blog, I thought the first post should be on where it all started. What would have been the first MACHINE that Mankind discovered.?.... well no one knoes the exact answers but we have evidences n theories n hypothesis n lots more.... Before answering that we must understand " what is or can be called a machine?"...

Any thin that reduces human effort is machine.. i would say an automobile , a boiler or even a ceiling fan would a complex example.... looking simpler examples , we can say that spoon is machine... two pieces of stone if rubbed together can produce a spark, is a machine.... list goes on ...

In this blog , being a mechanical engineer, I will try to bring in front of u what ever mechanical i can find..... discoveries..... inventions... facts.. theories... troubles and also their shootings.... I would humbly request my readers to come forward n post ur comments n suggesions... for am just trying to discover a new hobby .....

So together , lets blog.... LETS MECHBLOG......