Blower for circulating larger gas volumes, in particular for high-power laser systems

Claim 1

A blower for circulating large gas volumes, in particular for high-power laser systems of the gas transportation type, comprising: gas transportation means having a first and a second gas duct for receiving and guiding said gas under circulation, said gas ducts being interconnected by a connection duct; a radial compressor being rotatable about a vertical axis and having an upper compressor element extending into said connection duct to blow said gas from said first to said second gas duct and having further a flat lower surface, said surface being provided with spiral grooves; a pressure-tight housing block arranged below said gas transportation means and having a flat upper surface opposite said flat lower surface and being surrounded by an atmosphere; a vertical bore extending from said flat upper surface; a vertical drive shaft rigidly connected with said radial compressor and said flat lower surface to rotate therewith, said shaft being received in said bore; a first high-pressure gas chamber being formed between said flat lower surface and said flat upper surface under the action of said spiral grooves when said compressor is rotated, thus serving as an axial spiral flute bearing, said high-pressure gas chamber communicating with said second gas duct; a first axial sealing member arranged in said bore adjacent said flat upper surface to axially seal said shaft in said bore; a second axial sealing member arranged in said bore at a distance below said first axial sealing member to further axially seal said shaft in said bore, thus defining a lock chamber between said first and second axial sealing members and, further, defining a drive chamber below said second axial sealing member, said second axial sealing member comprising an axial upper sliding ring resting elastically on a lower thrust ring, and being connected about one circumference with one end of a bellows whose other end rests against one circumference of said housing, said thrust ring being seated on said shaft and comprising a lubricating-oil channel, connected to an axial lubricating oil supply duct in said drive shaft and having an upper bore connecting said channel with an opening in a sliding surface between said sliding ring and said thrust ring; radial bearing means arranged in said bore at a distance below said second axial sealing member, a lower bore in said thrust ring connecting said channel to an opening in a lower surface thereof directed towards said radial bearing means; a first fluid line connected to said lock chamber; a second fluid line connected to said drive chamber; a vacuum pump being connected to said first line to establish a pressure in said lock chamber that is below a pressure prevailing in said first high-pressure gas chamber; and a lubricating-oil pump being connected to said second fluid line.