390 



Motion of Gaseous Bodies. 



No. iil'DOl 



52 901. 1 : 10. 



52 903. 1 : 10. 



High -Vacuum Pumps with Oil-packed Piston, Kohl's System, German Patent. 



The advantages of these Oil Vacuum Pumps are that they are very easy to work, generate 

 a high vacuum, arc rapid in their action, and can be run in a simple, convenient and clean manner 

 without any special preparation. The Oil Pumps yield in a few minutes what it takes the Sprengel 

 mercury vacuum pump 1 hour to attain. These pumps are therefore peculiarly adapted both for de- 

 monstration purposes and specially for rapid working in laboratories. 



We would remark that in all pumps for which a vacuum of 0.0014 mm mercury column is 

 guaranteed, a vacuum of 0.0008 mm can be reached. 



Every Oil Vacuum Pump is accompanied by a Test Certificate. The test is made in our simps 

 with the MacLeod Vacuum Gauge having a 500 com measuring bulb (see No. 52,746). 



If, in the case of Pumps fitted with Electric Motors, a motor is desired for a different kind 

 of current or a different voltage from that quoted, a corresponding change in price is made. When 

 ordering pumps with electric motor drive, the type of current, network voltage (and in the case 

 of alternating or three-phase current, the freqency also) should be stated on each occasion. 



Complete description sent if desired. 



8. tl. 



52.901. Vacuum Pump with Oil-packed Piston and oil non-return valve, Kohl's system, German 

 Patent, Figure, with hand lever, with 1 barrel 40 mm internal diameter, stroke 



160 mm; with Plate 180 mm diameter, without receiver 5. u. I) 



Trie pump exhausts to ' .<!> mm. Largest Receiver which can be used: No. 53011 o. :). o 



52.902. --idem, with Fly- Wheel, for Hand and Power Drive, cf. Fitr. :>L'.9d9 (i. 10. o 



.">L'. 903. Vacuum Pump with Oil-packed Piston aiul oil non-return valve, Kohl's system, German 



Patent; larger, Figure; with Hand Lever, with 1 Barrel .~>d mm internal diameter; 



Stroke Itid mm; without Plate or Receiver <>. d. 



T/ie pump exli;msl< id ' I0 th mm. 



rtL',904. - - i (1 e m, with Hand Lever, with Plate -40 mm diameter, and Barometer Gauge 



200 mm high, Figure s. 10. 



Largest Receiver that ran be used: No. .">:!. U|:J I). I.'. I 



:.L'.90.-). - - idem, with Fly-wheel, for Hand and Power Drive, \\ithoul Plate, cf. Fig. .VJ,909 7. Id. 



rii,9d<;. -- idem, with Fly-wheel and with Plate 240 mm diameter and Barometer-Gauge 



200 mm Iii-h . . . Id. d. d 



:.L'.'.id7. Vacuum Pump with Oil-packed Piston and oil non-return valve. Kohl's system. German 

 Patent. Figure, with Hand Lever, larger than preceding; with 1 P.arrel (Id mm 

 internal diameter; Stroke 190 mm; without Plate S. Id. d 



The puiiiii exhaust*- to ' ,"> 





M. 911. !U-.' 



