HYDRAULICS & PNEUMATICS Presented by: Dr. Abootorabi Conditioning and Distribution of Compressed Air 1

HYDRAULICS & PNEUMATICS

Presented by: Dr. Abootorabi

Conditioning and Distribution of Compressed

Air

1

Conditioning and Storing Pneumatic System Air

Maximum pneumatic system operating efficiency is

achieved when system compressed air is:

Consistently clean

Free from moisture

At a relatively uniform temperature

2


Atmospheric air contains dirt under even the best of operating

conditions.

3


Pneumatic systems need to carefully filter the air taken

into the compressor intake to extend the service life of:

Compressor

Other system components

4


Air at construction sites is dirty.

5


Painting requires very clean air.

6


The temperature of both the intake and compressed air

is important:

Temperature changes are reflected in air pressure

and volume per the general gas law

Temperature influences the ability of air to retain

water vapor

7


Air in a pneumatic system may be cooled before,

during, or after compression:

Intake air temperature usually depends on the

location of the compressor air intake

Intercoolers and aftercoolers are used to remove

heat of compression

8


Intercoolers cool compressed air between the stages of a

multiple-stage compressor.

Aftercoolers cool the air after the air has been compressed.

Either air or water can be used as the cooling medium in

these devices.

9


Water vapor in air is referred to as humidity:

Essential to our natural environment

Can cause problems in a pneumatic system when

the temperature of the compressed air drops to the

dew point and the vapor condenses into liquid

water

10


Liquid water in a pneumatic system can:

Wash away lubricants

Increase component wear

Cause inconsistent system operation

Lower the finished quality of products directly

using the air in the manufacturing process

11


Liquid water forms in system lines and components

whenever the air temperature decreases to the dew point.

The first step in reducing the liquid water in compressed air

is to locate the atmospheric air intake of the compressor in

a protected area.

12


Condensation of the water vapor in compressed air can

occur in:

Aftercooler units

Moisture separator

System receiver

Distribution system

13


Specific air dryers can be used in pneumatic systems to

remove moisture:

Chemical desiccant

Refrigeration units

Specialized membranes

14


The receiver is the storage unit for compressed air.

Typically, the receiver is a metal, cylindrical tank with

domed ends.

In addition to air storage, the receiver:

Dampens system pressure pulsations

Removes water vapor from system air

In smaller systems, serves as the mount for the

prime mover and compressor15


Formulas are available for calculating the volume needed

for a receiver.

These formulas consider:

Cubic feet of free atmospheric air needed per minute

Desired cycle time

Atmospheric, initial receiver, and final receiver air

pressures

16

Air-Distribution System

The air distribution system delivers high-pressure,

conditioned air from the receiver to workstations with a

minimum of pressure drop.

The type of distribution system depends on the size of

the facility and the level of demand for compressed air.

17


Four general categories of air distribution systems are

used with pneumatic systems:

Centralized grid with fixed piping

Decentralized grid with fixed piping

Loop system with fixed piping

Flexible hoses for portable compressor systems

18


Centralized grid has one centralized compressor station

and one line network for a facility.

Decentralized grid has individual compressors in several

locations providing air to smaller distribution networks.

19


Centralized grid:

20


Decentralized grid:

21


Loop system has a main line that forms a continuous

loop with compressors located at one or more locations.

This design provides maximum airflow with a minimum

of pressure drop between the compressors and the

individual workstations.

22


Loop system:

23


Special attention must given to the setup of a hose air

distribution in order to minimize pressure drop:

Minimize hose length

Reduce the number of couplings

Eliminate kinks in the hose

Care must be taken to protect the hoses from abrasion

in the work environment.24


Typical hose

distribution system:

25

DeVilbiss Air Power Company


Proper sizing of pipe for a fixed air distribution system is

difficult.

Most systems operate under a variety of work conditions:

Multiple workstations

Varying actuator loads

Intermittent actuator operation26


Sizing is based on:

Rated actuator air consumption

Estimate of the time actuators are actually operating

Estimate of the percentage of maximum load

delivered during actuator operation

27


The pipe in air distribution lines should be installed with

a pitch of 1 per 10 of line:

Allows liquid water to drain to water traps

Water can be remove from traps either manually

or with automatic drain devices

28


Drop lines lead from the main air distribution line to the

workstations:

Should be attached to the top side of the distribution line

This prevents water in the distribution lines from

entering the workstation lines

29

Air-Distribution SystemProper slope and drop line installation:

30

Final Preparation of Air at the Workstation

Final preparation of air at a workstation is accomplished

by an FRL unit:

Air filter

Pressure regulator

Lubricator

31


Typical FRL unit:

32


FRL air filter removes:

Airborne dirt remaining in the atmospheric air

compressed in the system

Rust and scale from the interior of the distribution

lines

Liquid water that has condensed in the drop line

Atomized oil from the operating compressor

33


Typical air filter uses centrifugal force and porous filter

material to remove unwanted materials from system air:

Inlet passageway swirls the incoming air, creating a

centrifugal force that separates air and contaminants

Porous filter material traps other undesirable materials

34


Typical FRL air filter:

35

IMI Norgren, Inc.


FRL filters typically have a

drain.

36


The pressure regulator in an FRL unit reduces system

distribution line pressure to the level needed by

workstation tools and circuit actuators.

This unit is also necessary as air pressure in the

distribution line fluctuates due to varying air demands

and the characteristics of compressor-capacity control.

37


The lubricator in an FRL unit meters oil into pressurized

system air at the workstation.

This provides lubrication for system valves, actuators,

and air-powered tools.

38


Typical FRL lubricator:

39

IMI Norgren, Inc.


Rapidly moving system air passing through a lubricator

breaks up droplets of oil, forming a mist or fog.

This mist is transported through the workstation lines to

system components.

40

41


42


Distribution System Conductors and Fittings

Effectively moving compressed air through a distribution

system requires appropriate conductors and connectors.

Conductors can be classified as:

Rigid

Flexible

43


Pipe is the most common rigid conductor.

Hose is the most common flexible conductor.

Conductors must be properly sized and assembled for

compressed air to be transported from the compressor

to actuators with minimal pressure drop.

44


Conductors and the associated fittings must be properly sized.

45

IMI Norgren, Inc.


Various types of hose are available:

46

Atlas Copco


Hose selection, application, and maintenance are critical

to assure air distribution with a minimum loss of

pressure:

Hoses should be no larger than necessary

Use a minimum number of fittings

Layout lines to eliminate kinks and reduce the

number of bends

47

The end.

48

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HYDRAULICS & PNEUMATICS Presented by: Dr. Abootorabi Conditioning and Distribution of Compressed Air 1