Compressed Air Transmission and Treatment:Inducted contaminants

Inducted contaminants

Industrial stationary compressors are normally installed in separate rooms away from factory contaminants, drawing in air from the outside atmosphere as in Figure 3. The level of dust concentration is likely to be of the order of I0-50 mg/m 3• It is standard practice to fit the compressor with an intake filter, having an efficiency of the order of 99.9%, based on the dust concentration present in the ambient air (see Tables 3 and 4). The intake filter can be expected to pass all particles smaller than 5 micron as well as a proportion of the larger sizes. It will also pass atmospheric water vapour and all gases, bacteria and viruses.

Compressed Air Transmission and Treatment-0257

Compressed Air Transmission and Treatment-0258Compressed Air Transmission and Treatment-0259

Types of intake filters

Intake filters (Figure 4) commonly used are:

• Paper filters- with renewable elements used on all types of compressors. Filtering efficiency is high (over 99%) with a typical pressure drop of 2.5 to 3.5 mbar if correctly sized. They are not recommended for use with reciprocating compressors

Compressed Air Transmission and Treatment-0260

unless a pulsation chamber is incorporated between the filter and the compressor intake. They are not suitable for handling air in excess of 80°C.

• Fabric filters – stronger than paper and generally cleanable by back flow of compressed air and sometimes by washing.

• Oil bath filters- which have a higher solid retention capability than the above, with a capacity for collecting impurities equal to the mass of the oil. They are not suitable for use on piston compressors unloaded by closing the air inlet valve, unless installed with a bypass or check valve to prevent oil being blown back out of the filter with reversed air flow.

• Labyrinth type oil wetted filters- mostly used on small compressors inducting relatively clean air. They require periodic cleaning.

• Inertial filters – reverse flow or cyclonic, suitable for coarse filtering of large volumes of air. They are normally used as pre-filters in conjunction with one of the other types mentioned above.

The intake filter is normally specified by the compressor manufacturer based on the operating conditions.

Related posts:

Pumps:Positive displacement pumps
Applied Pneumatics:Circuit analysis
Compressed Air Transmission and Treatment:Activated carbon adsorption
Health and safety:Explosion protection
Health and safety:System components,Blowers ,compressors and Oil free air.
Low pressure and vacuum:Screw feeders and The simple screw feeder.
Optimizing and up-rating of existing systems:The influence of changing pipeline diameter
Conveying characteristics:The determination of conveying characteristics
ROUBLESHOOTING PNEUMA TIC CIRCUITS:GLOSSARY
Maintenance and troubleshooting:Cleanliness
Control components in a hydraulic system:Flow control valves.
Air receivers and compressor control.
Hydraulic Pumps and Pressure Regulation
Air Compressors, Air Treatment and Pressure Regulation:air treatment
SUMMARY OF INTRODUCTION TO FLUID MECHANICS

Leave a comment

Your email address will not be published. Required fields are marked *