AIR COMPRESSORS AND THEIR PERFORMANCE

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• Q1: Define Air Compressor.
  Ans: An air compressor is a machine that increases the pressure of air by reducing its volume. It takes air from the atmosphere and compresses it for various industrial uses.
• Q2: What is a Storage Vessel?
  Ans: A storage vessel is a closed container used to store compressed air. It maintains air pressure and supplies air when required.
• Q3: State the classification of Air Compressor.
  Ans: The classification of air compressor is as follows:

  • ➔ Reciprocating Compressor
  • ➔ Rotary Compressor
  • ➔ Single Stage Compressor
  • ➔ Multi Stage Compressor
• Q4: Define Reciprocating Compressor.
  Ans: A reciprocating compressor is a compressor in which air is compressed by the back and forth movement of a piston inside a cylinder.
• Q5: Define Rotary Compressor.
  Ans: A rotary compressor is a compressor in which air is compressed by the rotating motion of blades or vanes.
• Q6: Define Single Acting Compressor.
  Ans: A single acting compressor is a compressor in which air is compressed on only one side of the piston.
• Q7: Define Double Acting Compressor.
  Ans: A double acting compressor is a compressor in which air is compressed on both sides of the piston.
• Q8: Define Single Stage Compressor.
  Ans: A single stage compressor compresses air to the required pressure in one stage or one cylinder.
• Q9: Define Multi Stage Compressor.
  Ans: A multi stage compressor compresses air in more than one stage using two or more cylinders.
• Q10: Define Air Cooled Compressor.
  Ans: An air cooled compressor is a compressor in which heat produced during compression is removed by air.
• Q11: Define Water Cooled Compressor.
  Ans: A water cooled compressor is a compressor in which heat produced during compression is removed by circulating water.
• Q12: Define Inlet Pressure.
  Ans: Inlet pressure is the pressure of air at the entry of the compressor.
• Q13: Define Discharge Pressure.
  Ans: Discharge pressure is the pressure of air at the outlet of the compressor after compression.
• Q14: What is Free Air Delivery?
  Ans: Free air delivery is the actual volume of air delivered by a compressor measured at atmospheric pressure conditions.
• Q15: Define Compressor Capacity.
  Ans: Compressor capacity is the quantity of air delivered by the compressor per minute.
• Q16: Define Compression Ratio.
  Ans: Compression ratio is the ratio of discharge pressure to inlet pressure.
  Compression Ratio = Discharge Pressure / Inlet Pressure
• Q17: Define Swept Volume.
  Ans: Swept volume is the volume displaced by the piston during one stroke inside the cylinder.
• Q18: Briefly explain the working of Reciprocating Air Compressors.
  Ans: In a reciprocating air compressor, the piston moves downward and air enters through the inlet valve. During the upward movement, the air is compressed and its pressure increases. When the pressure becomes high, the discharge valve opens and compressed air is delivered.
• Q19: Define Multistage Compression.
  Ans: Multistage compression is a process in which air is compressed in two or more stages to achieve high pressure efficiently.
• Q20: State the advantages of Multistage Compression.
  Ans: The advantages of multistage compression are:

  • ➔ Higher efficiency
  • ➔ Less power consumption
  • ➔ Reduced temperature rise
  • ➔ Better lubrication
• Q21: What is a Two Stage Compressor with Intercooler?
  Ans: A two stage compressor with intercooler compresses air in two stages. An intercooler is placed between the stages to cool the air before entering the second stage, which improves efficiency.
• Q22: Define Roots Blower.
  Ans: A Roots blower is a type of rotary compressor that uses two rotating lobes to move air from inlet to outlet.
• Q23: Define Vane Blower.
  Ans: A vane blower is a rotary compressor in which rotating vanes trap and compress air inside a chamber.
• Q24: Define Axial Flow Compressor.
  Ans: An axial flow compressor is a compressor in which air flows parallel to the axis of rotation and gets compressed by rotating and fixed blades.
• Q25: Define Centrifugal Compressor.
  Ans: A centrifugal compressor is a rotary compressor in which air is compressed by the action of centrifugal force produced by a rotating impeller.
• Q26: State the working principle of Axial Flow Compressor.
  Ans: The axial flow compressor works on the principle of dynamic compression. Air flows parallel to the shaft and gains velocity from rotating blades. The fixed blades convert this velocity into pressure.
• Q27: State the working principle of Centrifugal Compressor.
  Ans: The centrifugal compressor works on the principle of centrifugal force. Air enters at the center of the impeller and is thrown outward by rotation. The high velocity air is converted into high pressure.
• Q28: What does Back Flow of Air means in Vanes Blower?
  Ans: Back flow of air in a vane blower means the leakage of compressed air from the discharge side back to the suction side due to clearance between parts.