Oil free air

Purge oxygen equipment with oil-free nitrogen or oil-free air prior to repairs. 

Screw compressors are rotary positive displacement machines. Two helical rotors are rotated by a senes of timing gears as shown in Figure 10-8 so that gas trapped in the space between them is transported from the suction to the discharge piping. In low-pressure air service, non-lubri-cated screw compressors can deliver a clean, oil-free air. In hydrocarbon service most screw compressors require that liquid be injected to help provide a seal. After-coolers and separators are required to separate the seal oil and recirculate it to suction. 

Figure 12-39D. Oil-free air compressor with two impellers, Elliott Company. Plant Air Package , Plus, gear driven. (Used by permission Bui. P-51 B. Elliott Company.)...

After the air clears the baffle section, it then passes through the wire mesh screen where any remaining oil is trapped. The relatively oil-free air continues to the air reservoir for storage. The air reservoir acts as a final... 

These methods are primarily for water vapor removal. Removal of lubricating oil is secondary, although all drying systems will reduce its carry-over. It should be understood that complete elimination of lubricating oil, particularly in the vapor form, is very difficult and that when absolutely oil-free air is required, some form of non-lubricated compressor is the best guaranteed method. 

Development of Self-Lubricating. Piston-Seal Materials for High-Pressure, Oil-Free Air Compressors , Rept No PAS-75-21, Naval Ship R D Center, Annapolis (1975) 3) T. Toshiaki ... 

Remove the solvent with a gentle current of dry, oil-free air, preferably at room temperature but never over 35° C. 

During construction it is impossible to avoid contamination of the piping with airborn ferrous particles from installation of structural steel and carbon steel piping components. If the stainless steel is kept dry, this may not be a problem. If the stainless steel piping is allowed to become wet, e.g., from a hydrostatic pressure test, the system should be tested with dry, oil-free air. If water is used, then provision must be made to thoroughly clean the system immediately after the hydrostatic pressure test. 

Figure 1 is a schematic diagram of the plant-scale process. The ozonated air for the sterilization process is produced as follows Completely oil-free air is supplied by a compressor specially equipped for the project. The compressor operates intermittently and automatically, furnishing air as required. Air pressure is maintained at 71 p.s.i. (5 kg. per sq. cm.) in a supply tank which smooths out sudden changes in pressure. On leaving this tank the purified air is cooled by water coils to a temperature of 15° to 18° C. 

Vials must be thoroughly washed, dried, sterilized, and depyrogenated. They should be handled in a clean room to minimize contamination by particulate matter. Washing is normally done in automated vial washers using purified water, filtered oil-free air, and a final rinse of WFI. 

Glass bottles may contain a variety of products, liquids, solids or gases (aerosols). The mode of filling therefore depends on the item being filled. However, prior to filling a container must be clean. Years ago all containers were washed, but other than sterile products and treated glass most bottles are usually inverted and air blown. To be effective air blowing must use dry oil-free air and have proper facilities for controlled removal of blown out debris (i.e. by vacuum). 

The packaging line cannot operate in isolation. It needs essential services, e.g. clean, dry, oil-free air, electricity, gases (nitrogen, oxygen), cooling water, vacuum, removal of waste material(s), removal of finished packs. 

Johnson and Krieger (5) using C -labeled acetylene in 0.1 per cent concentration in dry, oil-free air, working at less than atmospheric pressure, contact times of about 0.1 second, and at several temperatures, studied the completeness of removal of acetylene as a function of time of operation. The use of labeled acetylene and gas-counting techniques... 

Variety Year released Oil content (% dry basis) Protein content (% in oil-free meal dry basis) Glucosinolate content ( xmoles/g oil-free air dry meal)... 

For the 1983 shutdown work, a few drops of oil were added to the motor inlet before reactor operations, and the motor run on oil free air. 

It is important that no moisture or oil passes through the compressor and on to the blasted surface. Use a white rag to determine the quality. A black light may also be used to determine oil contamination. One hundred percent oil-free air can be supplied by rotary screw, two stage lubrication-oil-free compressors. 

The tanks are filled by means of an external PVC pipe from the delivery tanker to the top of the tank. It is recommended that tankers built to withstand pressure be discharged by means of air pressure from a compressor or from an independent clean, dry, oil-free air supply. Where tankers cannot withstand pressure they should be emptied by means of a titanium centrifugal pump. A drain point should be installed on the intake pipe to allow the pipe to be emptied into a container before breaking the connection from the tanker. 

Figure 8.2 View into an Opcon Auto rotor Twin-screw compressor providing oil-free air for use In pressurised fuel cell systems (photograph courtesy of Opcon).

After the equipment, parts, and piping have been mechanically cleaned and any abrasive material removed, the assembled piping should be blown with dry, oil-free air or nitrogen to remove small particles and any solvent vapors present. If drying is not completed using the residual heat in the metal, it can be completed with dry, oil-free air or nitrogen. If it is desirable that the equipment be maintained in a dry atmosphere before installation or use, the dew point of the contained atmosphere should not be higher than -30°F (-34.4°C). 

Equipment with large internal volumes may be filled to a slight positive pressure with dry, oil-free air or nitrogen after all openings have been sealed and valves closed. Parts in suitable plastic bags may be purged with inert gas or evacuated and sealed. The potential asphyxiation hazard needs to be considered if nitrogen is used. 

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