Saturday, April 30, 2016

Mechanical Engineering job questions Answer (Part: 1)

What is Boiler mountings and accessories> Write down three names of mountings and accessories. (Asuganj Power Station limited )
Mountings: These are the fittings which are mounted on the boiler for its proper and safe functioning. Boiler mountings are:-
1) Water level Indicator 2) Pressure Gauge 3) Blow-off-cock 4) Fusible plug 5) safety valve

Accessories: These are the devices which are used as integral parts of a boiler and help in running efficiently. Boiler accessories are:-
1) Feed pump 2) Economizer 3) Super heater

         What is parallel flow heat exchanger and counter current flow heat exchanger? (Asuganj Power station limited, Bangladesh Bank-2012 )
Parallel flow Heat Exchanger: Parallel flow heat exchangers, the fluid flow in the same direction. The temperature difference is maximum at inlet and rate of flow of heat and the rate of decrease of temperature are maximum here.
Counter-Current flow heat exchanger: In counter current flow heat exchanger the fluids flow in the opposite directions. The heat transfer takes place between the fluids at the moment when each is in its coldest state or when each is in its hottest state. The average temperature between two fluids is greater than in parallel flow heat exchanger.

         What is ton of refrigeration? (Asuganj Power Station Limited)
Ton of Refrigeration:  A ton of refrigeration is defined as the amount of refrigeration effect produced by the uniform melting of one ton (1000 Kg) of ice from and at 00C in 24 hours.

         Write down the Bernoulli’s Equation. (Asuganj Power station Company Limited)
Bernoulli’s Equation stats that for a perfect in-compressible liquid flowing in a continuous steam the total energy of particle remains the same while the particle moves from one point to another.
Mathematically, +  + Z1  =+  + Z2    

         What is the difference between shaper and Planer?
The fundamental difference between a shaper and planer is that in a Planer, the tool remains stationary and the work reciprocates whereas in a shaper, the work remains stationary and the tool reciprocates.

         What is absolute pressure? (DHAKA WASA )
Absolute Pressure = Atmospheric Pressure + Gauge Pressure

Friday, April 29, 2016

some definations

Baffle: A device to prevent direct fluid flow or impingement on a surface.
Hydraulic Pump: A device which converts mechanical force and motion into hydraulic fluid power by means of producing flow.
Hydraulic motor: A device which converts hydraulic fluid power into mechanical force and motion by transfer of flow under pressure. It usually provides rotary mechanical motion.