# Mechanical Interview Questions 8

Mechanical Interview Questions 8 contains question about...

71. Where Multi-stage pump used?

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

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

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

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

76 What is a radial-flow turbine?

77 What are four types of turbine seals?

78. What are two types of clearance in a turbine?

79. What is the function of a thrust bearing?

80 What are some conditions that may prevent a turbine from developing full power?

71. 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.

72. 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.

73. 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.

74. 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

75. 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.

76 What is a radial-flow turbine?

In a radial-flow turbine, steam flows outward from the shaft to the casing. The unit is usually a reaction unit, having both fixed and moving blades.

77 What are four types of turbine seals?

o Carbon rings fitted in segments around the shaft and held together by garter or retainer springs.

o Labyrinth mated with shaft serration’s or shaft seal strips.

o Water seals where a shaft runner acts as a pump to create a ring of water around the shaft. Use only treated water to avoid shaft pitting.

o Stuffing box using woven or soft packing rings that are compressed with a gland to prevent leakage along the shaft.

78. What are two types of clearance in a turbine?

o Radial – clearance at the tips of the rotor and casing.

o Axial – the fore-and-aft clearance, at the sides of the rotor and the casing.

79. What is the function of a thrust bearing?

Thrust bearings keep the rotor in its correct axial position.

80 What are some conditions that may prevent a turbine from developing full power?

o The initial steam pressure and temperature are not up to design conditions.

o The exhaust pressure is too high.

o The governor is set too low.

o The steam strainer is clogged.

o Turbine nozzles are clogged with deposits.

o Internal wear on nozzles and blades.