Oil-less piston compressors for compressed air and gases0 pages

Oil-less piston compressors for compressed air and gases

Oil-less compressorӔ applies to compressors running without a drop of oil inthe whole system, either in the guiding and compression part or in the crankmechanism. The lubrication of the running parts is dry without oil and is carried
out with special materials. The technology of oil-less and dry-running piston com-pressors was developed by the Swiss company Fritz Haug AG about 35 years ago.
In the beginning the compressors were primarily used for compressing air to 10to 40 bar. However based on further developments involving new materials andchanges to construction HAUG now provide an extensive assortment of air andgas compressors for oil-less and dry compression at low and high pressures.

Dipl.-Ing. Beat Frefel Fritz Haug AG, St. Gallen/Schweiz; Tel. +41 71 313 99 55E-mail: beat.frefel@haug.ch >

Oil-less compressors compressing without a drop of oil

Trunk-piston compressors havegained acceptance in the lower powerrange to 30 kW due to their simple andcompact construction next to compres-
sors with cross-heads. The compres-sion piston is directly driven by the con-necting rod in the trunk-piston compres-
sor. The cross-head with a piston rod as
well as the stuffing boxes to seal the run-ning piston rods are not necessary. Sim-ilar to electric motors, life long lubricat-
ed and sealed roller bearings are uti-lised to minimise any friction occurringin the crank mechanism. The connect-
ing rod bearings are assembled on thecrankshaft pin and exposed to the cen-trifugal force by it. Thanks to specially
developed bearings with a patented
connecting rod system, exchange inter-vals of 10,000 to 20,000 operation hours
can be achieved without maintenance
and after-lubrication. The use of high-
strength materials and the application oftight machine tolerances make it possi-ble to produce dry-running compres-
sors which are usable for continuous
operation under extreme climatic condi-
tions. Trunk-piston compressors are univer-sally usable for all operating modes be-
cause the oil-less compressor principle
means that oil lubrication films do not
need to build up and therefore they can
be started and stopped without damag-ing the mechanism. This feature is partic-ularly important in applications where the
compressors have long downtimes, for
example if the compressors are used for
stand-by or in emergency operations.

Picture 1: Oil-less piston compressor: i.e no oil in the whole compressor. Picture 2: Piston and connecting rod assembly ready to install with special roller bearings and a teflon base for piston guidance. Due to the alu-minium construction and the small piston stroke only very small mass forces arise. The compres-sors therefore run with extremely small vibra-tions. A foundation is not required. Picture 4: Due to their construction the 2-part piston rings offer consistently high quality so that the compression efficiency is maintained at a high level throughout the whole period of opera-
tion. The choice of the piston ring material and the piston ring form is determined by the com-
pression media and the mode of operation. Picture 3: The rust free cylinders surfaces are coated, honed with special machines, thermical-ly tempered and hardened. >
Off print ֓Industriepumpen + Kompressoren Է edition 4/2002 pages 188 - 191 ׷ Vulkan-Verlag, Essen size="-1">