| Compressed Air |
| A.
Air |
| 1. |
Ordinary
air refers to gas without color, odor or flavor.
It is a mixture of many gases and the ingredients
and contents shall be as follows:
| Ingredients |
Percentage
of dimension |
Percentage
of ingredient |
| Nitrogen |
78.08% |
75.50% |
| Oxygen |
20.94% |
23.14% |
| Argon |
0.94% |
1.3% |
| CO2 |
0.03% |
0.05% |
| Others (steam, helium, neon,...etc.) |
0.01% |
0.01% |
|
| 2. |
Gas is a kind
of material comprising numerous micro molecules,
which keep moving in the space. |
| 3. |
The energy
of gas is generated by the movements of molecules.
The higher the temperature is, the faster movements
of molecules will be. |
| 4. |
As the temperature
increase, the moisture increases, and vice-versa. |
| 5. |
Due to the
earth gravitational force 99% of air is concentrated
at the atmospheric layer 32Km above ground. |
| 6. |
An increase
of CO and CO2 will affect the air quality
and ease temperature to rise, thus aiding the
green house effect. |
|
| B. Compression
|
| 1. |
 Air elements contained in
a cylinder will move within the inner walls. Once
dimension of air is compressed and becomes smaller,
it will cause accelerated movement of air elements.
Increased impact will generate pressure. |
| 2. |
In the course
of air compression, the compression of air element
and friction within will increase the pressure
and temperature. On the contrary, when air expands
it will lower down the pressure and temperature. |
| 3. |
The lowered temperature
and pressure resulting from air compression will
cause coagulation and sedimentation of water and
impurities; whereas the main sediment will be
water, dust/particle, waste oil, rust and acids.
|
| 4. |
SO2
in the compressed air will become H2SO3,
which will cause corrosion, and will damage vital
parts of the air compressor.
|
|
| C. Compressed
Air System |
Clean
air is most essential to functions of a compressed
air system. Clean air is a better source of power
for safe, effective and reliable operation of
compressed air system. However, such pollutant
matter as oily mud, dirt, rust, acids and water
will cause damage to compressed air system and
would result in the following severe consequences:
|
| 1.
|
Locking
of pneumatic controlled instruments. |
| 2. |
Decreasing the
efficiency of pneumatic tools. |
| 3. |
Wearing at air-tight
seal ring and will corrode parts of the compressor. |
| 4. |
Increasing maintenance
cost. |
| 5. |
Lowering
product quality, adverse impact upon operation
of machinery equipment or event to the extent
of shut-down of the entire plant.
|
Typical
Compressed Air System
 |
| 1.
Compressor |
| 2.
Aftercooler |
| 3.
Separators |
|
4. Wet Receiver |
| 5.
3 Valve By-pass |
| 6.
Compressed Air Dryer |
| 7.
Coalescing Filter |
| 8.
Clean/Dry Receiver |
| 9.
Particulate Filter |
| |
|
|
| |
To
assure smooth operation of an air compressor and
pneumatic tools, the following requirements should
be strictly observed in operation of compressed
air system:
|
| 1. |
Selecting
the optimal environment. |
| 2. |
Selecting
the outstanding facilities. |
| 3. |
Correct
layout and installation of the air compressor. |
| 4.
|
Conduct
a scheduled maintenance. |
| 5. |
Filtering
and discharge of water and impurities. |
|
| D. Discharge
of Water and Dirty Scale and Automatic Drain Valve |
| To keep cleanliness
in compressed air system and upgrade quality in the compressed
air, you may be required to install filter devices such
as a separator, filter, or dryer. However the majority
of such filter devices should be installed to the auto
drain valve to remove water and impurities, which will
not only prolong the life span of filter device but also
upgrade efficiency. Therefore, the effective auto drain
valve plays a key role in the operation of compressed
air system. Automatic drain valve comprises a big variety,
such as float ball type, solenoid type, reversed cylinder,
sensor type and differential pressure type. However, ordinary
drain valve may have such defects as incomplete drainage,
congestion by dirt particles, excessive consumption of
gas, use of power that will make the system vulnerable
to malfunctions. |
|
