Question

1) What is the difference of dynamic compressor (blowers) and normal compressor? Name 2 types of pump from each category

2 )Sketch and explain two types of blowers;

Subject ( Application of Pneumatic and Hydraulics)

Answer 1

1)

Positive Displacement Compressor( Normal compressor):

1. Compresses fixed packets of fluid.
2. The velocity of fluid need not be high.
3. Gives constant flow rate against variable output pressure.
4. The fluid is directly imparted pressure energy.

Dynamic Compressor:

1. Compresses the fluid in continuous manner.
2. The velocity of fluid must be high.
3. Gives variable flow rate against variable output pressure.
4. The fluid is provided kinetic energy which is converted into pressure energy.

✓ Name 2 types of pump from dynamic compressor are i) Centrifugal pump and ii) Axial compressor.

✓ Name 2 types of pumpfpump normal compressor are i) Plunger pump and ii) Piston pump.

2.

1. Positive Displacement / Rotary Lobe Blowers:

A positive displacement blower has a function that’s straightforward yet effective. Air or gas enters through an expanding section on one side and exits through a decreasing section on the other side. To put it simply, positive displacement blowers trap and then release the air.

Positive displacement blowers maintain a constant speed and flow regardless of changes in pressure. You can use these blowers to move both air and neutral gases.

If the discharge valve is closed, positive displacement blowers will continue to flow and could burst the line. That’s why safety valves are crucial for this blower.

One type of positive displacement blower is the Rotary lobe blowers which consist of two rotors spinning in opposite directions. The blower sucks in air, and the lobes spin the air around before pushing it out.

One of the best aspects of rotary lobe blowers is they produce a high volume of air, which is crucial for vacuum systems. However, this air has low pressure (about 15 psi), so a rotary lobe blower is not the best choice for applications that require high pressure.

Another benefit to rotary lobe blowers is that they take little maintenance and work with most blower systems. But they do let some air escape, so they are not the most energy-efficient blower option. They are incredibly loud but can be quieted with silencers.

2. Heli​​​cal Screw Blowers:

Each helical screw blower has a main rotor with two lobes. This rotor fits into the flute of a second rotor. The two rotors turn in a helical pattern that is carefully timed so they do not contact each other.

Helical screw blowers typically produce air at higher pressures than rotary lobe blowers do. They also perform more quietly than rotary lobe blowers.

These intricate blowers are energy-efficient options as well. The sealed design of helical screw blowers leads to a smooth air flow and limited air leakage. Helical screw blowers are used to move both air and gas, depending on the application.