H-50-4...
H-50-3...
H-50-2...
H-50-1...
Roots slide valve vacuum unit...
2SK(SK) Water Ring Pump-Large...
ZJC-1200A Roots...
Roots-water (steam) jet vacuum machine...
Roots rotary vane vacuum unit...
Roots atmospheric jet water ring pump vacuum machine...
Roots water ring (liquid ring) vacuum unit...