Placement Interview Questions | Latest Mechanical Engineering Interview Questions

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1. Where Multi-stage pump used

Pressure washing of Aircraft, Trains, Boats and Road vehicles as well as Spray washing of industrial parts and Electronic components.


2.  What is the function of Scoop in BFP (Boiler Feed Water Pump) in Thermal Power Station?

The Function of Scoop tube is regulating the varying amount of oil level in the coupling during operation of infinite variable speed.


3.  In the Thermal Power Plant why Deaerator (D/A) placed on height?

To build a Very high pressure and the temperature for a boiler feed water pump and it discharge high pressure water to the boiler.

And to provide the required Net Positive Suction Head (NPSH) for the BFW pump and to serve as a storage tank to ensure a continuous supply of feed water during rapid changes in BFP.


4.  How to determine the capacity of Refrigeration system? How we use Condenser coils, Compressor, Capillarity?

To determine the Refrigeration system by test of C.O.P and use the Condenser coils, Compressor, Capillarity, based on the properties


5.  In orifice why the Pressure and Temperature are decreases?

Orifice is a small hole like a nozzle. When a high pressure fluid passes through the orifice, Pressure gets reduced suddenly and the velocity of the fluid gets increased. Also the heat transfer rate increases. We know that Heat transfer rate is directly proportional to the difference in temperature, Area and the Heat transfer coefficient. Heat transfer Coefficient remains constant for a fluid at a particular temperature.     

Q= KA (T1-T2)

If the heat transfer rate increases, it seems the difference in temperature gets increased. There is no way in reduction of inlet temperature of the orifice. As a result, the outlet temperature of the orifice gets reduced. Hence the pressure and temperature gets reduced when it passes through orifice.


6.  What is the difference between Bolt and Screw?

The main difference was based on the load acting on it, and the size. For smaller loads, screws are enough but in case of greater-loads, bolts are to be used. In bolt we give centrifugal force or tangential force and screw we give axial force for driving.


Oscillating Conveyor System | Vibratory Oscillating System | Vibrating Conveyor Applications

Selection of vibratory conveyor:

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The oscillating motion of the trough is achieved via specially designed inclined arms and an eccentric shaft driven by a motor through V-belts. The eccentric shaft is mounted on anti friction bearings and has V-pulleys at both ends with weights on them to counteract the unbalancing force. The rotation of the eccentric shaft provides a forward and backward motion to a connecting arm attached to the trough through a rubberized pin. The trough motion is predominantly horizontal with some vertical component, which causes it to oscillate with a pattern conductive to conveying material. A retaining spring assembly at the back of the trough absorbs shock load. All components including drive motor are mounted on a rigidly constructed base frame.

Advantages:

· Hot and abrasive materials can be handled

· Cooling, drying and de-watering operation can be done during transport

· Scalping, screening or picking can be done

· Units can be covered and made dust tight

· Simple construction and low head room

· Can be made leak proof

Disadvantages:

· Relatively short length of conveying ( about 50m Maximum)

· Limited capacity, about 350 tons per hour for length of conveying of 30 m.

· Some degradation of material takes place.

Applications:

Vibratory conveyors find wide spread application in the transportation of dusty, hot, toxic, and chemically aggressive bulk material through a closed trough or pipe in chemical, metallurgical, mining industries and manufacturing of building materials.

Vibratory conveyors are also employed for transportation of steel chips in machine shop, hot knocked out sand, wastes and small castings in foundry shop. Vibratory feeders are also in use for delivery of small machine parts like screws, rivets etc.

Sticky materials like wet clay or sand are unsuitable for vibratory conveyors. In handling finely pulverized materials, like cement etc., the performance of such conveyors are reported to be poor.

Vibratory conveyors are hardly employed for handling common bulk loads, such as sand, gravel, coal etc as the same can be done more efficiency by belt conveyors.