1. Prepared by: Patel Nirav (130120119160)
Managed By Platinum Foundation
GANDHINAGAR INSTITUTE OF TECHNOLOGY
AICTE Approved | Affiliated With Gujarat Technological University
Control Engineering
( )
Mechanical Engineering
Prepared by: Patel Nirav ( )

2. Pneumatic control system
Topic:-
Pneumatic control system
Content:-
what are pneumatic ?
Advantage & Disadvantage of Compressed air pneumatic Systems
Working of pneumatic Control System
Air Compressors
Different types of Compressor
Efficiency of Compressor
Application
conclusion.

3. What are pneumatics ???
Mechanisms which use air pressure to apply mechanical force and displacement.
Commonly used in industry.
Pneumatic power users need not worry about hazardous leakage as the fuel is commonly just air, although other compressed gases such as carbon dioxide may be used.

4. Advantage Simple Easy to control Explosive proof
Easily transportable in vessels & pipes
Low cost of maintenance.
No return lines are required
Clean system, it has a self cleaning property.

5. Drawbacks High forces can not be transmitted
Cylinders can be subject to damage
Repair impossible
Provides a non-uniform speed
Inaccurate in operation
Creates a noise pollution
Expensive

6. How it works ??? Typically, pressure is applied to one port
while the other is
vented to atmosphere
So P is regulated
gauge pressure
(60 psi max)
⅛” NPTF Air Port (Retraction)
Seals
Piston
Rod
Cylinder
⅛” NPTF Air Port (Extension)

7. The pneumatic cylinder has following general characteristic.
Diameter = 2.5 to 320 mm
Stroke length = 1 to 2000 mm
Available forces = 2 to 45,000 N at 6 bar
Piston speed = 0.1 to 1.5 m/s
Stroke
Length

8. In pneumatic control system many topics are there such as air compressor, pneumatic filter, air pressure regulator, (FRL)filter, regulator, & lubricator unit, pressure control valve, direction control valve, 2 way valve, 3 way valve, shuttle valve, pilot valve, etc. But here we study about air compressor in briefly.

9. What is air compressor ??? Manufacture company
An air compressor is a device that takes in air at atmospheric pressure and delivers it at a higher pressure by reducing its volume.
Compressor :- a mechanical device that compresses gases.
Manufacture company
DeWalt
California Air Tools
Makita
Senco
Porter-Cable

10. Types of air compressor :
Type of
compressor
Positive
displacement
Reciprocating
Rotary
Dynamic
Centrifugal
Axial

11. In the positive-displacement type, a given quantity of air or gas is trapped in a compression chamber and the volume it occupies is mechanically reduced, causing a corresponding rise in pressure prior to discharge. At constant speed, the air flow remains essentially constant with variations in discharge pressure. Dynamic compressors impart velocity energy to continuously flowing air or gas by means of impellers rotating at very high speeds. The velocity energy is changed into pressure energy both by the impellers and the discharge volutes or diffusers. In the centrifugal-type dynamic compressors, the shape of the impeller blades determines the relationship between air flow and the pressure (or head) generate

12. Reciprocating air compressor
During the downward motion of the piston, the pressure inside the cylinder falls below the atmospheric pressure and the inlet valve is opened due to pressure.
The air is taken into the cylinder until the piston reaches bottom dead positions.
As the piston starts moving upward, the inlet valve is closed and the pressure is increasing continuously until the pressure inside cylinder is above the pressure of delivery side which to the receiver.
Then delivery valve open and air transfer to receiver.

13. PV diagrame:
Referring to the diagram, the theoretical air compressor PV diagram can be understood

14. Rotary air compressor
In this compressor, the suction and delivery valve replaced by port and a piston replaced by helical screw.
It consists of two helical screws which are mesh with each other.
An electrical motor drives a male rotor and female are driven by male rotor.

15. Centrifugal air compressor
It consists of rotating impeller, diffuser, casing, driven shaft, impeller eye etc.
The impeller run at speed 20,000 to 30,000 r.p.m.
The diffuser is important part of compressor which surrounding the impeller and provides diverging passage for air flow thus increasing the pressure air.

16. Axial Flow compressor
It consists of a casing fitted with several rows of fixed blades and rotor attached with several rows of moving blades.
The fixed and moving blades are placed on alternate rows the function of the fixed blades is to receive the high velocity air from the moving blades.
Speed may be vary from 10,000 to 30,000 RPM. Pressure ratio of 10:1 can be achieved.

17. Reciprocating compressor efficiencies
Mechanical efficiency
ῃ= I.P/B.P
(2) Isothermal efficiency
ῃiso = p1 V1 loge (p2/P1)
[ (n/n-1) p1V1 (p2/p1)n-1/n -1}]
Volumetric efficiency
ῃ = 1- C [(p2/p1)1/n -1)]

18. Pneumatic Application in industry
Pneumatic actuators are extensively used by the Chemical Process Industry due to their intrinsic safety and their ability to fail safe.
2-position
pneumatic
actuator
driving a
4-way
ball valve
pneumatically
driven flow
control valves
(butterfly type

19. Pneumatic Application:
Pneumatic cutter

20. Pneumatic Application:
Pneumatics is used in carrying out machining & working operation.
For ex:
Drilling
Turning
Milling
Sawing
Finishing
Forming
Quality control

21. Conclusions
Air compressor is a supply of air which generates air that is stored in a tank.
we have seen the actual operation of an Air compressor and its theoretical PV diagram.