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Q1. Name three reasons for considering the use of pneumatics instead of hydraulics.

Ans.Three reasons for considering the use of pneumatics instead of hydraulicsare: -

  • By definition, pneumatic defines the study of mechanical motion or movement due to the pressurized gases while hydraulics is used in controlling or harnessing power with the use of pressurized fluids.
  • Hydraulics uses an incompressible fluid medium like oil whereas pneumatics uses a compressible gas like air.
  • Hydraulic applications demand greater pressures (above one thousands) during operations whereas pneumatic applications only require 100 psi pressures more or less.

Q2. State Boyle’s, Charles and Gay – Lussac’s laws.

Ans. Boyle’s law:

It states that at constant temperature for a definite amount of gas the product of pressure and volume is equal to constant. It means

PV = constant







At constant T

                Pand n









Charles Law:

It states that at constant pressure for a definite amount of gas volume is directly proportional to temperature. It means

V ∝ T



                T     At constant P

and n










Gay – Lussac’s Law:

It states that under similar condition of temperature and pressure whenever gases react together the volume of the reacting gases as well as product (if gases) bear a simple whole number ratio.

Ex: -


Q3. Name three types of air compressor.

Ans.Three types of compressor are following: -

Reciprocating Air Compressors

Reciprocating air compressors are positive displacement machines, meaning that they increase the pressure of the air by reducing its volume. This means they are taking in successive volumes of air which is confined within a closed space and elevating this air to a higher pressure. The reciprocating air compressor accomplishes this by a piston within a cylinder as the compressing and displacing element.


Rotary Screw Compressors

Rotary air compressors are positive displacement compressors. The most common rotary air compressor is the single stage helical or spiral lobe oil flooded screw air compressor. These compressors consist of two rotors within a casing where the rotors compress the air internally. There are no valves. These units are basically oil cooled (with air cooled or water cooled oil coolers) where the oil seals the internal clearances.


Centrifugal Compressors

The centrifugal air compressor is a dynamic compressor which depends on transfer of energy from a rotating impeller to the air.Centrifugal compressors produce high-pressure discharge by converting angular momentum imparted by the rotating impeller (dynamic displacement). In order to do this efficiently, centrifugal compressors rotate at higher speeds than the other types of compressors. These types of compressors are also designed for higher capacity because flow through the compressor is continuous.


Q4. What is a multistage compressor?

In a multistage air compressor the air is get cooled at two stages to improve the efficiency on jobs. This kind of compressor is mainly used in the large industries and commercial sectors where long term used is required. In this the compressed air is cooled in the secondary tank when it transfers from a high pressure tank to a lower pressure unit. In this process generate very low heat compared to the single stage compressor.


Q5. Describe the function of an air filter.

Ans. Air filter is a very important part of an automobile intake system. The main work of this air filter is to filter the air coming from the surrounding and provide a clean air to the in-late manifold. Air filter is situated between the inlet manifold and surrounding. It mainly absorb the impurity like small particles, dust and many more impurities from the air and gives engine a clean air which is further used to burn the fuel in the combustion chamber.


Q6. Describe the function of an air pressure regulator.

Ans. Pressure regulator is a device which mainly controls the flow of fluid at a certain pressure. Basically it is a valve which cuts the flow of fluid when it exceeds it upper limit for a certain pressure. Air pressure regulator is used to control the flow of air at a certain pressure.



Q7. What is meant by the term dew point?

Ans. Dew point is a temperature at which the water vapor condenses (at constant barometric pressure) into liquid water at the same rate at which it evaporates. This condense water is called as dew when form a solid surface. In one word we can say tha the dew point is water to air saturation temperature.

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Q1. Name xxxxxxx reasons for xxxxxxx the use xxxxxxx xxxxxxx instead xxxxxxx hydraulics.

Ans.Three reasons xxxxxxx considering the xxxxxxx of xxxxxxx xxxxxxx of hydraulicsare: xxxxxxx definition, pneumatic xxxxxxx the study xxxxxxx mechanical motion xxxxxxx movement due xxxxxxx the pressurized xxxxxxx xxxxxxx hydraulics xxxxxxx used in xxxxxxx or harnessing xxxxxxx with xxxxxxx xxxxxxx of pressurized xxxxxxx

  • Hydraulics xxxxxxx an incompressible xxxxxxx medium like xxxxxxx whereas pneumatics xxxxxxx a compressible xxxxxxx xxxxxxx air.
  • Hydraulic xxxxxxx demand greater xxxxxxx (above one xxxxxxx during xxxxxxx xxxxxxx pneumatic applications xxxxxxx require 100 xxxxxxx pressures more xxxxxxx less.
  • Q2. xxxxxxx Boyle’s, Charles xxxxxxx Gay – xxxxxxx xxxxxxx Boyle’s xxxxxxx states that xxxxxxx constant temperature xxxxxxx a xxxxxxx xxxxxxx of gas xxxxxxx product of xxxxxxx and volume xxxxxxx equal to xxxxxxx It means

    PV xxxxxxx constant



                    xxxxxxx n





    Charles Law:

    It xxxxxxx that at xxxxxxx pressure for xxxxxxx definite amount xxxxxxx xxxxxxx volume xxxxxxx directly proportional xxxxxxx temperature. It xxxxxxx ∝ xxxxxxx xxxxxxx src="file:///C:/Users/ANKITA/AppData/Local/Temp/msohtmlclip1/01/clip_image004.gif" width="12" xxxxxxx T     At xxxxxxx P

    and xxxxxxx align="left" cellpadding="0" xxxxxxx height="12"> 





                                                                    xxxxxxx – Lussac’s xxxxxxx states that xxxxxxx similar xxxxxxx xxxxxxx temperature and xxxxxxx whenever gases xxxxxxx together the xxxxxxx of the xxxxxxx gases as xxxxxxx as product xxxxxxx xxxxxxx bear xxxxxxx simple whole xxxxxxx ratio.

    Ex: -


    Q3. xxxxxxx three types xxxxxxx air compressor.

    Ans.Three xxxxxxx of compressor xxxxxxx following: -

    Reciprocating xxxxxxx Compressors

    Reciprocating air xxxxxxx xxxxxxx displacement machines, xxxxxxx that they xxxxxxx the pressure xxxxxxx the xxxxxxx xxxxxxx reducing its xxxxxxx This means xxxxxxx are taking xxxxxxx successive volumes xxxxxxx air which xxxxxxx confined within xxxxxxx xxxxxxx space xxxxxxx elevating this xxxxxxx to a xxxxxxx pressure. xxxxxxx xxxxxxx air compressor xxxxxxx this by xxxxxxx piston within xxxxxxx cylinder as xxxxxxx compressing and xxxxxxx element.


    Rotary Screw xxxxxxx xxxxxxx compressors xxxxxxx displacement compressors. The xxxxxxx common rotary xxxxxxx compressor xxxxxxx xxxxxxx single stage xxxxxxx or spiral xxxxxxx oil flooded xxxxxxx air compressor. xxxxxxx compressors consist xxxxxxx two rotors xxxxxxx xxxxxxx casing xxxxxxx the rotors xxxxxxx the air xxxxxxx There xxxxxxx xxxxxxx valves. These xxxxxxx are basically xxxxxxx cooled (with xxxxxxx cooled or xxxxxxx cooled oil xxxxxxx where the xxxxxxx xxxxxxx the xxxxxxx clearances.


    Centrifugal Compressors

    The xxxxxxx air compressor xxxxxxx a dynamic compressor xxxxxxx xxxxxxx on transfer xxxxxxx energy from xxxxxxx impeller to the xxxxxxx compressors produce xxxxxxx discharge by xxxxxxx angular momentum xxxxxxx xxxxxxx the xxxxxxx impeller (dynamic xxxxxxx In order xxxxxxx do xxxxxxx xxxxxxx centrifugal compressors xxxxxxx at higher xxxxxxx than the xxxxxxx types of xxxxxxx These types xxxxxxx compressors are xxxxxxx xxxxxxx for xxxxxxx capacity because xxxxxxx through the xxxxxxx is xxxxxxx xxxxxxx What is xxxxxxx multistage compressor?

    Ans. xxxxxxx xxxxxxx is a xxxxxxx important part xxxxxxx an automobile xxxxxxx system. The xxxxxxx work of xxxxxxx air filter xxxxxxx xxxxxxx filter xxxxxxx air coming xxxxxxx the surrounding xxxxxxx provide xxxxxxx xxxxxxx air to xxxxxxx in-late manifold. xxxxxxx filter is xxxxxxx between the xxxxxxx manifold and xxxxxxx It mainly xxxxxxx xxxxxxx impurity xxxxxxx small particles, xxxxxxx and many xxxxxxx impurities xxxxxxx xxxxxxx air and xxxxxxx engine a xxxxxxx air which xxxxxxx further used xxxxxxx burn the xxxxxxx in the xxxxxxx xxxxxxx Describe xxxxxxx function of xxxxxxx air pressure xxxxxxx Pressure xxxxxxx xxxxxxx a device xxxxxxx mainly controls xxxxxxx flow of xxxxxxx at a xxxxxxx pressure. Basically xxxxxxx is a xxxxxxx xxxxxxx cuts xxxxxxx flow of xxxxxxx when it xxxxxxx it xxxxxxx xxxxxxx for a xxxxxxx pressure. Air xxxxxxx regulator is xxxxxxx to control xxxxxxx flow of xxxxxxx at a xxxxxxx xxxxxxx What xxxxxxx meant by xxxxxxx term dew xxxxxxx Dew xxxxxxx xxxxxxx a temperature xxxxxxx which the xxxxxxx vapor condenses xxxxxxx constant barometric xxxxxxx into liquid xxxxxxx at the xxxxxxx xxxxxxx at xxxxxxx it evaporates. xxxxxxx condense water xxxxxxx called xxxxxxx xxxxxxx when form xxxxxxx solid surface. xxxxxxx one word xxxxxxx can say xxxxxxx the dew xxxxxxx is water xxxxxxx xxxxxxx saturation xxxxxxx

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