... r/min),high efficiency,small volume,light weight,and compact structure.2.2Air cooling structure,pressure rise ... ensures reliable running with low noise under the high pressure condition.2.4Precision harden-teeth-surface helical timing ... with filter,outler silencer,pully,belts,belts cover,pressure release valve, check valve,flexible joint,pressu- ... to ask me. oxygen making use high pressure roots blowers